The document summarizes the endocrinal response to stress. It discusses how stress activates the hypothalamic-pituitary-adrenal axis through corticotropin-releasing factor (CRF) and arginine vasopressin (AVP). CRF plays a central role in regulating the stress response and release of adrenocorticotropic hormone (ACTH) from the pituitary gland which then stimulates glucocorticoid release from the adrenal cortex. Glucocorticoids provide feedback inhibition of the HPA axis to terminate the stress response.
This is a presentation made on stress and related problems related to physiological aspects of it. It also explains General Adaption Syndrome i.e our bodies response to stressor hormone like Oxytocin and cortisol in basic 3 stages, also some of the sympathetic and parasympathetic functions. It gives you general idea about the "Stress curve" .
Hormones affect almost every system in the body and can be classified by their structure and function. The document discusses steroid and peptide hormones and how hormones maintain homeostasis and control reproductive functions. It also examines the hierarchical control of hormones and how stress hormones like cortisol are involved in the fight or flight response during times of stress. Sex hormones contribute to differences in brain structure and cognitive abilities between males and females.
Circadian rhythms refer to biological cycles that occur over approximately 24 hours. The suprachiasmatic nucleus (SCN) in the hypothalamus acts as the master pacemaker regulating circadian rhythms. Lesions to the SCN abolish circadian rhythms, while transplanted SCN tissue can impart rhythms to recipient animals. The SCN receives light input from retinal ganglion cells that contain melanopsin photoreceptors sensitive to blue light wavelengths.
The document discusses the physiology of stress in humans. It explains that stress is the body's response to any difficult event or stressor, whether physical, psychological, or social. The body's stress response evolved in our ancestors to help them fight or flee from threats. When stressed, the sympathetic nervous system is activated, causing changes like increased heart rate, blood pressure, and blood sugar that provide energy for fighting or fleeing. While this response was useful for surviving threats in the past, modern stressors are often chronic and the stress response can be harmful if constantly activated. Prolonged stress can negatively impact the immune system over time.
This document discusses chemical messengers and hormones, including:
1. Chemical messengers can be categorized as local messengers, neurotransmitters, neuropeptides, hormones, and pheromones. Hormones differ in that they are secreted by endocrine glands and circulate through the bloodstream to target distant cells.
2. Hormones control biochemical reactions in target cells by increasing substance transport, stimulating enzyme/protein synthesis, or activating/suppressing enzymes. The major classes of hormones are proteins, amines, steroids, and eicosanoids.
3. Hormone secretion is regulated by feedback control systems, which can be either positive or negative. Negative feedback systems help maintain
EPSP is an excitatory postsynaptic potential that occurs when a neurotransmitter like glutamate binds to receptors on the postsynaptic neuron, making its membrane permeable to sodium ions and depolarizing the neuron. IPSP is an inhibitory postsynaptic potential that occurs when GABA binds to receptors, making the membrane permeable to chloride ions and hyperpolarizing the neuron. EPSPs can summate and cause the neuron to generate an action potential, while IPSPs make action potential generation less likely. Together, the balance of EPSPs and IPSPs control whether a neuron will fire an action potential.
This document discusses cardiovascular regulation through humoral, neuronal, and local control systems. It provides details on various vasodilators and vasoconstrictors that regulate blood flow and pressure through humoral mechanisms. Key neuronal control centers in the medulla are described, including the vasomotor center, nucleus ambiguus, and nucleus tractus solitarius. The roles of the sympathetic and parasympathetic nervous systems in regulating heart rate and blood vessel tone are also outlined.
This is a presentation made on stress and related problems related to physiological aspects of it. It also explains General Adaption Syndrome i.e our bodies response to stressor hormone like Oxytocin and cortisol in basic 3 stages, also some of the sympathetic and parasympathetic functions. It gives you general idea about the "Stress curve" .
Hormones affect almost every system in the body and can be classified by their structure and function. The document discusses steroid and peptide hormones and how hormones maintain homeostasis and control reproductive functions. It also examines the hierarchical control of hormones and how stress hormones like cortisol are involved in the fight or flight response during times of stress. Sex hormones contribute to differences in brain structure and cognitive abilities between males and females.
Circadian rhythms refer to biological cycles that occur over approximately 24 hours. The suprachiasmatic nucleus (SCN) in the hypothalamus acts as the master pacemaker regulating circadian rhythms. Lesions to the SCN abolish circadian rhythms, while transplanted SCN tissue can impart rhythms to recipient animals. The SCN receives light input from retinal ganglion cells that contain melanopsin photoreceptors sensitive to blue light wavelengths.
The document discusses the physiology of stress in humans. It explains that stress is the body's response to any difficult event or stressor, whether physical, psychological, or social. The body's stress response evolved in our ancestors to help them fight or flee from threats. When stressed, the sympathetic nervous system is activated, causing changes like increased heart rate, blood pressure, and blood sugar that provide energy for fighting or fleeing. While this response was useful for surviving threats in the past, modern stressors are often chronic and the stress response can be harmful if constantly activated. Prolonged stress can negatively impact the immune system over time.
This document discusses chemical messengers and hormones, including:
1. Chemical messengers can be categorized as local messengers, neurotransmitters, neuropeptides, hormones, and pheromones. Hormones differ in that they are secreted by endocrine glands and circulate through the bloodstream to target distant cells.
2. Hormones control biochemical reactions in target cells by increasing substance transport, stimulating enzyme/protein synthesis, or activating/suppressing enzymes. The major classes of hormones are proteins, amines, steroids, and eicosanoids.
3. Hormone secretion is regulated by feedback control systems, which can be either positive or negative. Negative feedback systems help maintain
EPSP is an excitatory postsynaptic potential that occurs when a neurotransmitter like glutamate binds to receptors on the postsynaptic neuron, making its membrane permeable to sodium ions and depolarizing the neuron. IPSP is an inhibitory postsynaptic potential that occurs when GABA binds to receptors, making the membrane permeable to chloride ions and hyperpolarizing the neuron. EPSPs can summate and cause the neuron to generate an action potential, while IPSPs make action potential generation less likely. Together, the balance of EPSPs and IPSPs control whether a neuron will fire an action potential.
This document discusses cardiovascular regulation through humoral, neuronal, and local control systems. It provides details on various vasodilators and vasoconstrictors that regulate blood flow and pressure through humoral mechanisms. Key neuronal control centers in the medulla are described, including the vasomotor center, nucleus ambiguus, and nucleus tractus solitarius. The roles of the sympathetic and parasympathetic nervous systems in regulating heart rate and blood vessel tone are also outlined.
The hypothalamus is a small brain structure located below the thalamus that regulates many homeostatic functions including body temperature, hunger and thirst, circadian rhythms, hormone secretion, and the autonomic nervous system. It contains several nuclei that control these functions. The hypothalamus receives input from the limbic system and senses changes in the body to regulate the autonomic nervous system and pituitary gland to maintain homeostasis. Disorders of the hypothalamus can disrupt functions like sleep, emotions, temperature regulation, and hormone secretion.
Physiology of Neuromodulation and neuromodulators. Difference between neuromodulation and synapse. Recent advances in neuromodulation, clinical application of neuromodulation.
This document provides an overview of the hypothalamus presented by Dr. Nilesh Kate. It begins with objectives and definitions of the hypothalamus. It then covers the physiological anatomy including external features, subdivisions, nuclei and connections. Major sections discuss the functions of the hypothalamus in areas like autonomic function, sleep/wake cycles, food intake regulation, endocrine function, temperature regulation and more. The final section covers applied aspects like lesions of the hypothalamus and associated clinical conditions such as diabetes insipidus and narcolepsy.
The reticular formation is a network of neurons located in the brainstem that performs several important functions. It receives sensory information from the spinal cord and senses arousal levels. The reticular formation contains nuclei that are involved in motor control, sleep-wake cycles, autonomic functions, and modulating pain. It has ascending and descending pathways that connect to the thalamus and cerebral cortex and help regulate states of consciousness like sleep and wakefulness.
This document discusses neurotrophic factors, which are growth factors that influence neuron proliferation, differentiation, survival, and death. The neurotrophic factor hypothesis proposes that neurons require specific neurotrophic factors for survival, and neurons without adequate access to these factors die by apoptosis. The major neurotrophins discussed are NGF, BDNF, NT-3, and NT-4, which bind to specific receptors on neurons. Neurotrophins are involved in cell survival, proliferation, differentiation, learning and memory, and synaptic plasticity. Reduced levels of BDNF in mice lead to abnormal behavior and early death. BDNF levels are also reduced in neurodegenerative diseases. New strategies for delivering neurotrophins in a
This document provides an overview of physiology of sleep and sleep disorders. It discusses brain waves during different sleep stages, the cycles of non-REM and REM sleep, theories of what causes sleep, the effects of sleep on physiological functions, comparative aspects of sleep across species, and consequences of sleep deprivation. Key topics covered include the different sleep stages, roles of neurotransmitters like serotonin in regulating sleep, and restoration of brain and body during sleep.
Advanced nutrition for the brain series: stress, the HPA-axis and neuroinflammation. Targeted nutritional interventions for successful treatment of mental health conditions.
Inflammation is a major contributing factor to chronic modern illness and is driven, in part, by chronic stress and HPA-axis over stimulation. Mental health conditions, in particular clinical depression, are increasingly linked with neuroinflammation. As such, anti-inflammatory interventions are known to result in significant clinical benefits.
During this webinar Dr Bailey will discuss the biological mechanisms linking stress, chronic inflammation and mood disorders, together with a review of the current evidence for a targeted, anti-inflammatory nutrition approach to treatment. Nina will also clarify why some of the recent trials have failed to report benefits and how to optimise your anti-inflammatory interventions to treat clients with anxiety, depression, schizophrenia and PTSD.
This document discusses various neurotrophic factors and cytokines. It describes neurotrophins like nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin 3 and 4/5 that promote nerve growth, survival and neuronal plasticity through Trk and p75 receptors. Other growth factors discussed are leukemia inhibitory factor, insulin-like growth factor, fibroblast growth factor, transforming growth factor and platelet-derived growth factor. Cytokines are small protein molecules that regulate the immune response through local and systemic effects.
This document summarizes oxytocin and vasopressin (antidiuretic hormone or ADH). It describes that oxytocin is secreted by the hypothalamus and posterior pituitary and acts on mammary glands to cause milk ejection and on the uterus to facilitate birth and transport of sperm. ADH is also secreted by the hypothalamus and pituitary and has two main actions - retaining water in the kidneys by increasing water reabsorption and vasoconstriction. Conditions of inappropriate hypersecretion and hyposecretion of each hormone are also summarized.
Posture is maintained through a combination of muscle tone and reflexes. The muscles that maintain posture contain a high proportion of slow-twitch fibers to allow for sustained contraction. Postural reflexes integrate inputs from proprioceptors, the vestibular system and visual system to make continuous corrections to muscle activity and maintain balance. The spinal cord, brainstem and cerebellum are involved in regulating these reflexes. Upright human posture relies on minimal muscle activity but reflex adjustments of antigravity muscles in response to sway to oppose the effects of gravity.
What is the fight or flight response finalGodschild24
A quick powerpoint explaining what the fight or flight response is. There is also a simple diagram showing the after-effects of the fight or flight response.
Neurobiology of sleep_disorders_lattova(5280ab0cb6099)Hena Jawaid
This document provides an overview of neurobiology of sleep and sleep disorders. It defines normal sleep, describes the circadian rhythm and two-process model that regulate sleep-wake cycles. It outlines the reticular activating system and flip-flop switch that control transitions between wake and sleep states. Non-REM and REM sleep are characterized based on EEG patterns. Polysomnography and other tools for measuring sleep are discussed. Common sleep disorders like insomnia are introduced.
This document summarizes key aspects of sleep and sleep disorders. It describes the sleep-wake cycle including non-REM (NREM) sleep which makes up 75-80% of sleep and is characterized by slow wave sleep, and REM sleep which makes up 20-25% and features rapid eye movements. It discusses EEG wave patterns in different sleep stages and underlying brain regions and chemicals involved in sleep regulation. Common sleep disorders like sleep apnea, insomnia and parasomnias are outlined. Physiological changes in breathing, heart rate and brain activity during sleep are also summarized.
Neuropeptides are small protein-like molecules that neurons use to communicate with each other. They influence various brain and bodily functions. Some peptides act as both hormones and neuropeptides. Neuropeptide Y (NPY) is involved in processes like feeding, learning, and social behavior. It has therapeutic potential for treating obesity and anxiety/depression. Calcitonin gene-related peptide (CGRP) is a vasodilator that may be linked to migraines. Substance P is associated with pain and inflammation. Cholecystokinin is a gut-brain hormone involved in processes like feeding and anxiety. Many neuropeptides act through G-protein coupled receptors and have potential pharmacological applications.
The document discusses the adrenal medulla and the hormones epinephrine and norepinephrine. It notes that the adrenal medulla is part of the autonomic nervous system and secretes the hormones to prepare the body for fight or flight responses. It also summarizes key functions of epinephrine and norepinephrine such as increasing heart rate, blood pressure, and metabolism. Feedback mechanisms and antagonistic hormones work to regulate levels of epinephrine and maintain homeostasis.
The pituitary gland, also known as the hypophysis, is a small gland located at the base of the brain that regulates several important bodily functions. It has two lobes - the anterior pituitary and posterior pituitary. The anterior pituitary secretes hormones that control other endocrine glands and regulates various bodily processes. These hormones include TSH, FSH, LH, ACTH, GH, and prolactin. The posterior pituitary stores and releases oxytocin and vasopressin (ADH) which are produced in the hypothalamus and help regulate fluid balance and labor. The pituitary gland acts as a master gland that controls other endocrine glands and relays signals from the hypothalamus to help maintain
This document discusses learning and memory processes in the brain. It describes how learning occurs through reflexive and associative mechanisms, including habituation, sensitization, classical and operant conditioning. It also outlines the different types of memory including implicit, explicit, short-term and long-term memory. Key areas involved in memory encoding, storage and retrieval are the hippocampus and prefrontal cortex. Conditions like Alzheimer's disease are discussed as they impact higher cognitive functions mediated by these brain regions.
The document summarizes the endocrine response to stress and injury. It discusses three main points:
1. The stress response involves three stages - alarm reaction, resistance, and exhaustion - mediated by the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. Hormones like cortisol and adrenaline are released to mobilize energy stores.
2. Injury triggers a neuroendocrine response through afferent neuronal signaling to the hypothalamus. Hormones released include ACTH, cortisol, antidiuretic hormone, and catecholamines which work to restore circulating volume and provide energy substrates.
3. Journals discuss the role of the neuro
This document discusses polyamines, which are biologically important molecules that possess multiple amino groups. The key polyamines are putrescine, spermine, and spermidine. Spermine and spermidine were originally detected in human semen. Polyamines are synthesized from ornithine and S-adenosyl methionine precursors. Ornithine decarboxylase regulates polyamine synthesis. Polyamines are basic molecules that associate with nucleic acids and are essential for processes like cell growth, proliferation, and membrane stability. Levels of excreted polyamines are elevated in many cancer types, so polyamines can be diagnostic markers for cell proliferation and destruction.
The hypothalamus is a small brain structure located below the thalamus that regulates many homeostatic functions including body temperature, hunger and thirst, circadian rhythms, hormone secretion, and the autonomic nervous system. It contains several nuclei that control these functions. The hypothalamus receives input from the limbic system and senses changes in the body to regulate the autonomic nervous system and pituitary gland to maintain homeostasis. Disorders of the hypothalamus can disrupt functions like sleep, emotions, temperature regulation, and hormone secretion.
Physiology of Neuromodulation and neuromodulators. Difference between neuromodulation and synapse. Recent advances in neuromodulation, clinical application of neuromodulation.
This document provides an overview of the hypothalamus presented by Dr. Nilesh Kate. It begins with objectives and definitions of the hypothalamus. It then covers the physiological anatomy including external features, subdivisions, nuclei and connections. Major sections discuss the functions of the hypothalamus in areas like autonomic function, sleep/wake cycles, food intake regulation, endocrine function, temperature regulation and more. The final section covers applied aspects like lesions of the hypothalamus and associated clinical conditions such as diabetes insipidus and narcolepsy.
The reticular formation is a network of neurons located in the brainstem that performs several important functions. It receives sensory information from the spinal cord and senses arousal levels. The reticular formation contains nuclei that are involved in motor control, sleep-wake cycles, autonomic functions, and modulating pain. It has ascending and descending pathways that connect to the thalamus and cerebral cortex and help regulate states of consciousness like sleep and wakefulness.
This document discusses neurotrophic factors, which are growth factors that influence neuron proliferation, differentiation, survival, and death. The neurotrophic factor hypothesis proposes that neurons require specific neurotrophic factors for survival, and neurons without adequate access to these factors die by apoptosis. The major neurotrophins discussed are NGF, BDNF, NT-3, and NT-4, which bind to specific receptors on neurons. Neurotrophins are involved in cell survival, proliferation, differentiation, learning and memory, and synaptic plasticity. Reduced levels of BDNF in mice lead to abnormal behavior and early death. BDNF levels are also reduced in neurodegenerative diseases. New strategies for delivering neurotrophins in a
This document provides an overview of physiology of sleep and sleep disorders. It discusses brain waves during different sleep stages, the cycles of non-REM and REM sleep, theories of what causes sleep, the effects of sleep on physiological functions, comparative aspects of sleep across species, and consequences of sleep deprivation. Key topics covered include the different sleep stages, roles of neurotransmitters like serotonin in regulating sleep, and restoration of brain and body during sleep.
Advanced nutrition for the brain series: stress, the HPA-axis and neuroinflammation. Targeted nutritional interventions for successful treatment of mental health conditions.
Inflammation is a major contributing factor to chronic modern illness and is driven, in part, by chronic stress and HPA-axis over stimulation. Mental health conditions, in particular clinical depression, are increasingly linked with neuroinflammation. As such, anti-inflammatory interventions are known to result in significant clinical benefits.
During this webinar Dr Bailey will discuss the biological mechanisms linking stress, chronic inflammation and mood disorders, together with a review of the current evidence for a targeted, anti-inflammatory nutrition approach to treatment. Nina will also clarify why some of the recent trials have failed to report benefits and how to optimise your anti-inflammatory interventions to treat clients with anxiety, depression, schizophrenia and PTSD.
This document discusses various neurotrophic factors and cytokines. It describes neurotrophins like nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin 3 and 4/5 that promote nerve growth, survival and neuronal plasticity through Trk and p75 receptors. Other growth factors discussed are leukemia inhibitory factor, insulin-like growth factor, fibroblast growth factor, transforming growth factor and platelet-derived growth factor. Cytokines are small protein molecules that regulate the immune response through local and systemic effects.
This document summarizes oxytocin and vasopressin (antidiuretic hormone or ADH). It describes that oxytocin is secreted by the hypothalamus and posterior pituitary and acts on mammary glands to cause milk ejection and on the uterus to facilitate birth and transport of sperm. ADH is also secreted by the hypothalamus and pituitary and has two main actions - retaining water in the kidneys by increasing water reabsorption and vasoconstriction. Conditions of inappropriate hypersecretion and hyposecretion of each hormone are also summarized.
Posture is maintained through a combination of muscle tone and reflexes. The muscles that maintain posture contain a high proportion of slow-twitch fibers to allow for sustained contraction. Postural reflexes integrate inputs from proprioceptors, the vestibular system and visual system to make continuous corrections to muscle activity and maintain balance. The spinal cord, brainstem and cerebellum are involved in regulating these reflexes. Upright human posture relies on minimal muscle activity but reflex adjustments of antigravity muscles in response to sway to oppose the effects of gravity.
What is the fight or flight response finalGodschild24
A quick powerpoint explaining what the fight or flight response is. There is also a simple diagram showing the after-effects of the fight or flight response.
Neurobiology of sleep_disorders_lattova(5280ab0cb6099)Hena Jawaid
This document provides an overview of neurobiology of sleep and sleep disorders. It defines normal sleep, describes the circadian rhythm and two-process model that regulate sleep-wake cycles. It outlines the reticular activating system and flip-flop switch that control transitions between wake and sleep states. Non-REM and REM sleep are characterized based on EEG patterns. Polysomnography and other tools for measuring sleep are discussed. Common sleep disorders like insomnia are introduced.
This document summarizes key aspects of sleep and sleep disorders. It describes the sleep-wake cycle including non-REM (NREM) sleep which makes up 75-80% of sleep and is characterized by slow wave sleep, and REM sleep which makes up 20-25% and features rapid eye movements. It discusses EEG wave patterns in different sleep stages and underlying brain regions and chemicals involved in sleep regulation. Common sleep disorders like sleep apnea, insomnia and parasomnias are outlined. Physiological changes in breathing, heart rate and brain activity during sleep are also summarized.
Neuropeptides are small protein-like molecules that neurons use to communicate with each other. They influence various brain and bodily functions. Some peptides act as both hormones and neuropeptides. Neuropeptide Y (NPY) is involved in processes like feeding, learning, and social behavior. It has therapeutic potential for treating obesity and anxiety/depression. Calcitonin gene-related peptide (CGRP) is a vasodilator that may be linked to migraines. Substance P is associated with pain and inflammation. Cholecystokinin is a gut-brain hormone involved in processes like feeding and anxiety. Many neuropeptides act through G-protein coupled receptors and have potential pharmacological applications.
The document discusses the adrenal medulla and the hormones epinephrine and norepinephrine. It notes that the adrenal medulla is part of the autonomic nervous system and secretes the hormones to prepare the body for fight or flight responses. It also summarizes key functions of epinephrine and norepinephrine such as increasing heart rate, blood pressure, and metabolism. Feedback mechanisms and antagonistic hormones work to regulate levels of epinephrine and maintain homeostasis.
The pituitary gland, also known as the hypophysis, is a small gland located at the base of the brain that regulates several important bodily functions. It has two lobes - the anterior pituitary and posterior pituitary. The anterior pituitary secretes hormones that control other endocrine glands and regulates various bodily processes. These hormones include TSH, FSH, LH, ACTH, GH, and prolactin. The posterior pituitary stores and releases oxytocin and vasopressin (ADH) which are produced in the hypothalamus and help regulate fluid balance and labor. The pituitary gland acts as a master gland that controls other endocrine glands and relays signals from the hypothalamus to help maintain
This document discusses learning and memory processes in the brain. It describes how learning occurs through reflexive and associative mechanisms, including habituation, sensitization, classical and operant conditioning. It also outlines the different types of memory including implicit, explicit, short-term and long-term memory. Key areas involved in memory encoding, storage and retrieval are the hippocampus and prefrontal cortex. Conditions like Alzheimer's disease are discussed as they impact higher cognitive functions mediated by these brain regions.
The document summarizes the endocrine response to stress and injury. It discusses three main points:
1. The stress response involves three stages - alarm reaction, resistance, and exhaustion - mediated by the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. Hormones like cortisol and adrenaline are released to mobilize energy stores.
2. Injury triggers a neuroendocrine response through afferent neuronal signaling to the hypothalamus. Hormones released include ACTH, cortisol, antidiuretic hormone, and catecholamines which work to restore circulating volume and provide energy substrates.
3. Journals discuss the role of the neuro
This document discusses polyamines, which are biologically important molecules that possess multiple amino groups. The key polyamines are putrescine, spermine, and spermidine. Spermine and spermidine were originally detected in human semen. Polyamines are synthesized from ornithine and S-adenosyl methionine precursors. Ornithine decarboxylase regulates polyamine synthesis. Polyamines are basic molecules that associate with nucleic acids and are essential for processes like cell growth, proliferation, and membrane stability. Levels of excreted polyamines are elevated in many cancer types, so polyamines can be diagnostic markers for cell proliferation and destruction.
This document discusses polyamine synthesis and metabolism. It notes that ornithine and S-adenosylmethionine are precursors for polyamine synthesis. Ornithine decarboxylase converts ornithine to putrescine, and putrescine is then converted to spermidine and spermine with involvement of S-adenosylmethionine and decarboxylated S-adenosylmethionine. Polyamine oxidase can break down polyamines by oxidizing spermine to spermidine and putrescine, which are then excreted. Polyamines are involved in nucleic acid and protein synthesis.
ROLE OF JASMONIC ACID IN PLANT DEVELOPMENT &DEFENCE MECHANISMBHU,Varanasi, INDIA
jasmonic acid is a plant immune hormone whicch are imortant for plant defence mechanism and development..its have important role in root growth inhibition,tuber formation,trichome formation ,senescence,flower developmentand increasing arbasculer mycorrhizal activity in root plants,recently it has been reported in various development in rice crop like spikelet development etc.....in defence its play a crucial role against insect and pathogen resistance.Recent insights into the JAs mediated plant defense cascade and better knowledge of key regulation of plant growth and development processes will help us to design future crops with increased biotic stress resistance and better adaptability under changing climate
Auxins and gibberellins would enhance stem elongation and fruit growth.
- Auxins promote cell elongation and division, resulting in stem elongation.
- Gibberellins also promote stem elongation by overcoming the inhibitory effect of other hormones.
- Ethylene and cytokinins generally do not directly promote stem or fruit growth. Cytokinins promote cell division but not elongation. Ethylene inhibits stem elongation.
- Abscisic acid and phytochrome are not directly involved in promoting stem or fruit growth. Abscisic acid inhibits growth and phytochrome regulates photoperiodism.
Therefore, the correct answer is A - Auxins and gibberellins.
The document summarizes plant stress responses to both abiotic and biotic stresses. It discusses how plants detect stress signals and trigger responses across multiple levels, from gene expression changes to production of protective proteins and metabolites. Stress responses aim to acclimate the plant and prevent damage through avoidance, tolerance and adaptation mechanisms. Key responses include production of heat shock proteins under heat stress, osmolytes for drought and salt tolerance, and pathogenesis-related proteins and phytoalexins as antimicrobial defenses against pathogens.
This document discusses the hypothalamic-pituitary-adrenal (HPA) axis and its role in the stress response. It covers how the HPA axis is activated through neuronal signaling pathways in response to stress. It also discusses potential disturbances to the HPA axis from factors like traumatic brain injury, prenatal stress, genetics and neurodegenerative diseases. Finally, it outlines treatments for dysregulation of the HPA axis, including lifestyle interventions, nutritional supplements, and antidepressant medications that aim to help the body better manage stress responses.
The document discusses the relationship between stress, the hypothalamic-pituitary-adrenal (HPA) axis, and immune function. It summarizes that psychological stressors activate the HPA axis and increase glucocorticoid release from the adrenal glands. Prolonged high glucocorticoid levels can damage the hippocampus and impair HPA regulation, sensitizing the stress response. Early life stress may also program the HPA axis and increase risk of mental illnesses. The document reviews evidence that stress and glucocorticoids influence immune function and that CRH antagonists show promise in treating depression and stress-related disorders by regulating abnormal HPA activity.
The document discusses the hypothalamic-pituitary-adrenal (HPA) axis and its role in the central stress response system. The HPA axis activates in response to stressors and involves the hypothalamus releasing corticotropin-releasing factor (CRF) which stimulates the pituitary gland to release adrenocorticotropic hormone (ACTH). ACTH then signals the adrenal cortex to secrete cortisol, helping the body adapt. If stress continues long-term, the HPA axis can become dysregulated, impairing the body's defenses and health. The General Adaptation Syndrome model also describes the three stages - alarm, resistance, and exhaustion - that the body progresses
The document discusses stress, its types (eustress and distress), stages (alarm, resistance, exhaustion), physiology involving the sympathetic-adreno-medullary axis and hypothalamus-pituitary-adrenal axis. It then covers stress-related disorders like depression and diabetes, their symptoms, diagnosis, relation to stress, and management using yoga and naturopathy. It also discusses lifestyle-related disorders like obesity and their prevention and management with yoga and naturopathy case studies provided as examples.
Serotonin is a monoamine neurotransmitter synthesized from tryptophan. It is found extensively in the gastrointestinal tract and in serotonergic neurons in the central nervous system. Serotonin receptors include 5-HT1-7 and are involved in various physiological functions like mood, appetite, sleep, and pain perception. Imbalances in the serotonergic system are associated with disorders like depression, anxiety, schizophrenia, and impulse control disorders. Drugs that affect the serotonergic system include SSRIs, SNRIs, triptans, 5-HT3 antagonists, buspirone, and MAOIs.
This document provides an overview of measuring autonomic nervous system regulation through various physiological tools. It begins with background on the autonomic nervous system and its role in the stress response. Tools that can measure aspects of the autonomic nervous system like cardiac, skin conductance, respiratory, and vascular activity are identified. A decision tree is provided to help choose the best tools depending on setting, purpose, ease of use, and validity. The goal is to use these tools to measure changes in autonomic nervous system activation from techniques like mind-body skills and monitor ability to return to homeostasis after stress.
Molecular mechanisms that control circadian rhythms - Mohammed Elreishi Mohammed Elreishi
Circadian rhythms are driven by an internal
biological clock that anticipates day/night cycles to
optimize the physiology and behavior of organisms.
The 2017 Nobel Prize in Physiology or Medicine is
awarded to Jeffrey C. Hall, Michael Rosbash and
Michael W. Young for their Discoveries of Molecular Mechanisms Controlling the Circadian Rhythm.
NEURO ENDOCRINOLOGY CONTENT BY VELVEENA.Mvelveenamaran
The document discusses neuroendocrinology, which is the interaction between the nervous system and endocrine system. It describes how the hypothalamus controls the pituitary gland, which is referred to as the "master gland" as it controls other endocrine glands. The pituitary gland has two lobes - the anterior lobe secretes hormones that control other glands, while the posterior lobe stores and releases hormones produced by the hypothalamus. Key hormones discussed include growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, gonadotrophins, oxytocin, vasopressin, and thyroid hormones. The document concludes by noting the relevance of neuroendocrinology to understanding brain disorders
The document discusses the chemical control of brain and behavior through the neuroendocrine system. It describes how hormones secreted by the hypothalamus and pituitary gland regulate other glands and body processes through feedback loops. Key topics covered include the types of hormones, hormone actions, locations and functions of the hypothalamus, pituitary and other endocrine glands, and their roles in homeostasis and stress response.
This document discusses circadian rhythm dysregulation in bipolar disorder. It summarizes that circadian rhythms control physiological and behavioral cycles over 24 hours, and disturbances in these rhythms can contribute to psychiatric disorders like bipolar disorder. Evidence from animal and clinical studies supports a link between circadian abnormalities and bipolar disorder. Specifically, patients with bipolar disorder may experience a shortening of the circadian period length which can lead to a desynchronization of internal rhythms with the external light-dark cycle. This misalignment has been correlated with the switching between manic and depressive mood states in bipolar disorder.
This document provides an introduction to the endocrine system. It describes the endocrine system as consisting of glands that secrete hormones directly into the bloodstream to regulate distant target organs and tissues. Some key points mentioned include:
- Hormones are chemical messengers that influence cellular activity, especially related to growth and metabolism.
- Homeostasis is maintained by both the autonomic nervous system and endocrine system, with hormones providing slower, more precise adjustments.
- Major endocrine glands include the pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, thymus, ovaries and testes.
Adrenocorticotropic hormone (ACTH) is a linear peptide with α-melanocyte stimulating hormone (α-MSH) and corticosteroid-like mid-leaf peptides derived from pro-opiomellin precursor.
This document discusses stress-induced immune dysfunction. It explains that stress can suppress immune function through pathways like the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. Brief acute stress may enhance some immune parameters while chronic stress adversely affects immunity. Stress hormones released during stress responses can directly or indirectly impact immune cells and their cytokine production, resulting in quantitative and qualitative immune changes linked to health risks.
Steroids in oral and maxillofacial surgeryshivani gaba
Corticosteroids are hormones produced in the adrenal cortex that regulate processes throughout the body like metabolism, immune function, and stress response. They work through binding to glucocorticoid receptors that activate or repress gene expression. While essential for life, corticosteroids also have many therapeutic uses due to their ability to reduce inflammation and suppress the immune system. This document discusses the history, physiology, mechanisms of action, pharmacokinetics, therapeutic uses, and management of patients taking corticosteroids.
Define acute and chronic health and medicine homework help.docx4934bk
Acute stress is a short-term response to perceived threats like accidents or presentations, while chronic stress is long-term response to ongoing issues like financial problems. The amygdala detects stress and sends danger signals to the hypothalamus via the brainstem, activating the HPA axis and releasing stress hormones. Hormones like cortisol prepare the body for prolonged stress responses. Strategies to counter stress include relaxation, exercise, sleep, and maintaining social support systems.
STRESS IN THE FAMILY CHARACTERISTICS , CATEGORY, CONSEQUENCE AND NEED FOR STR...hemurathore1
A little stress every now and then is not something to be concerned about. Ongoing, chronic stress, however, can cause or exacerbate many serious health problems, including.
Mental health problems, such as depression, anxiety, and personality disorders
Cardiovascular disease, including heart disease, high blood pressure, abnormal heart rhythms, heart attacks, and stroke
Obesity and other eating disorders
Menstrual problems
Ongoing chronic stress, however can cause or exacerbate many serious health problems, including: Mental health problems such as anxiety, depression and personality disorders.
Cardiovascular diseases, including heart disease, high blood pressure, abnormal heart rhythms, heart attacks, and stroke.
PSYC 380Research Paper Grading RubricStudentCriteriaPoi.docxpotmanandrea
PSYC 380
Research Paper Grading Rubric
Student:
Criteria
Points Possible
Points
Earned
Instructor’s Comments
Content/Development
All key elements of the assignment are covered in a substantive way.
125
Content is comprehensive, accurate, and/or persuasive.
Major points are stated clearly and are supported by professional literature or logic.
Meaningful use of source material and analytical reasoning to elaborate upon the topic or theme.
Research is adequate and timely for the topic.
The context and purpose of the writing are clear.
Organization
The introduction provides sufficient background on the topic and previews major points.
25
Ideas flow in a logical sequence.
The structure of the paper is clear and easy to follow.
The paper’s organization emphasizes the central theme or purpose.
Paragraph transitions are present, logical, and direct the flow of thought throughout the paper.
The conclusion logically derives from the paper’s ideas.
The conclusion reviews the major points for the appropriate audience.
Format
The paper includes a title page, an abstract, 8–10 full pages of content, and a references page
50
The references page contains at least 5 scholarly sources.
The paper follows current APA format guidelines.
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25
Spelling is correct.
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Sentences are complete, clear, and concise.
25
Sentences are well constructed with consistently strong and varied structure.
Sentence transitions are present and direct the flow of thought.
Words used are precise and unambiguous.
Total
250
INTRODUCTION
Stress is a complex condition with emotional, cognitive, and
biological factors. Excessive stress causes long- and short-term
disability in the various human systems, and activates the defense
system of the central nervous system. The stress responses differ
depending on the type of stress and the individual’s physiological
responses. These latter responses consist of neuro-endocrine and
behavioral responses, and include the changes in the activity and
immune function of the hypothalamo-pituitary-adrenal (HPA) axis.
Sleep is an important component of human homeostasis.
Sleep disorders are closely associated with significant medical,
psychological and social disturbances. Chronic sleep restriction is
an increasing problem in many countries. Since the body’s stress
systems play a critical role in adapting to a continuously changing
and challenging environment, it is an important question whether
these systems are affected by sleep loss. The human body mobilizes
defensive processes in an adaptive effort to maintain homeostasis.
If these defenses fail, insomnia may occur. Short-term insomnia is
caused by a change in routine ...
This document discusses stress and its effects on the body. It describes the body's immediate and long-term responses to stress, including increased heart rate and sweating in the short term and high blood pressure in the long term. It also discusses the types of stress including psychological, chronic, and acute stress and their symptoms. Chronic stress can negatively impact health over time if left untreated. The document outlines how the hypothalamic-pituitary-adrenal axis responds to regulate stress hormones like cortisol and how acute stress causes a short-term physical adaptation through hormone release and redirection of resources.
The pituitary gland, also known as the hypophysis, is located at the base of the brain and is divided into the anterior and posterior pituitary. The posterior pituitary stores and releases two hormones, antidiuretic hormone and oxytocin, which are produced in the hypothalamus. The anterior pituitary produces six hormones that are regulated by hypothalamic releasing and inhibiting hormones: growth hormone, adrenocorticotropic hormone, thyroid stimulating hormone, prolactin, follicle stimulating hormone, and luteinizing hormone. These hormones control important metabolic and reproductive functions throughout the body.
How to Fix the Import Error in the Odoo 17Celine George
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Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
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it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
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You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
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Walmart Business+ and Spark Good for Nonprofits.pdf
Endocrinal response to stress
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3. ENDOCRINAL RESPONSE TO STRESS By D. AMIRA AHMED Ghiaty Endocrinology and Geriatric Unit Zagazig Faculty Of Medicine
4. Human respond to stress by activating a wide array of behavioral and physiological responses that are collectively referred to as the stress response. Corticotropin-releasing factor (CRF) plays a central role in the stress response by regulating the hypothalamic-pituitary-adrenal (HPA) axis.
5. The stress response is subserved by: a complex neuroendocrine, cellular and molecular infrastructure, which is located in both the central nervous system and the periphery.
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10. Concomitantly, physicaladaptation occurs principally to promote an adaptive redirection of energy. Thus, oxygen and nutrients are shunted to the central nervous system (CNS) and the stressed body site(s), where they are needed the most……………Increases in cardiovascular tone, respiratory rate, and intermediate metabolism (gluconeogenesis, lipolysis) all work in concert to promote availability of vital substrates, while energy consuming functions such as digestion, reproduction, growth, and immunity are temporally suspended.
11. In parallel to the adaptive response, restrainingforces are also activated during stress in order to prevent a potential excessive response of the components of the stress system. The ability of the individual to timely and accurately develop the restraining forces that prevent such an overresponse is equally essential for a successful general adaptive response.
12. If the counteracting forces of the body fail to control the elements of the stress response in a precise manner, the prolongation of the initial adaptive responses may turn maladaptive and contribute to the development of disease.
13. Components of the stress system
14. The central components of the stress system: are located in the hypothalamus and the brainstem and include the parvocellularcorticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) neurons of the paraventricular nuclei (PVN) of the hypothalamus, and the CRH neurons of the paragigantocellular and parabranchial nuclei of the medulla, as well as the locus ceruleus (LC) and other catecholaminergic cell groups of the medulla and pons (central sympathetic system) .
15. The peripheral components of this complex system. The peripheral limps of the hypothalamic-pituitary-adrenal (HPA) axis, together with the efferent sympathetic/adrenomedullary system .
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17. The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress.
19. CRF Regulates basal and stress-induced release of pituitary ACTH Detected in cerebral cortex, hypothalamus, anterior pituitary, adrenal glands, testis, ovary, gut, heart, and lungs Three homologus neuropeptides – Urcortin I, Urcortin II, and Urcortin III CRF gene expression can be altered (catecholamines, serotonin, cytokines, glucocorticoids)
21. CRH-R2 receptors are expressed mainly in the peripheral vasculature, the skeletal muscles, the gastrointestinal tract and the heart, but also exhibit a widespread distribution in subcortical structures of the brain, such as the lateral septum, amygdala, hypothalamus and brain stem.
22. CRF-continued CRF R1 Corticotrophs of the anterior pituitary Mediates actions of the HPA axis and anxiety-related behavior CRF R2 Brain and periphery Regulation of feeding behavior and cardiovascular function
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24. Hypothalamic-Pituitary-Adrenal axis This axis is a vital component of both the central and the peripheral limb of the stress system. At the level of the hypothalamic-pituitary unit, CRH is released into the hypophyseal portal system and acts as the principal regulator of the anterior pituitary ACTH secretion . The binding of CRH on the CRH-R1 receptors of the corticotrophs is permissive for the secretion of ACTH, while AVP acts as a potent synergistic factor of CRH with little ACTH secretagogue activity by itself.
25. In nonstressful situations, both CRH and AVP are secreted in the portal system in a circadian and highly concordant pulsatile fashion. The amplitude of the CRH and AVP pulses increases in the early morning hours, resulting eventually in increases of both the amplitude and frequency of ACTH and cortisolsecretory bursts in the general circulation. The circadian release of CRH/AVP/ACTH/cortisol in their characteristic pulsatile manner appears to be controlled by one or more pace makers, whose exact location in the brain is not known in humans. These diurnal variations are perturbed by changes in lighting, feeding schedules, and physical activity, and are disrupted when a stressor is imposed.
26. During acute stress, the amplitude and synchronization of the CRH and AVP pulsations increases, with additional recruitment of PVN CRH and AVP secretion. Especially in conditions of strong hypovolemic stress, such as created by marked hypotension or hemorrhage, additional AVP of magnocellular neuron origin is secreted into both the hypophysealportalsystem, via collateral neuraxon terminals, and into the systemic circulation. In addition, depending on the stressor, angiotensinII, as well as various cytokines and lipidmediatorsofinflammation are secreted and act on hypothalamic, pituitary and/or adrenal components of the HPA axis, mostly to potentiate its activity.
27. The adrenalcortexis the principal target organ of the pituitary-derived circulating ACTH. The latter is the key regulator of glucocorticoid and adrenal androgen secretion by the zonaefasciculata and reticularis, respectively, while it also participates in the control of aldosterone secretion by the zonaglomerulosa. Moreover, there is evidence suggesting that the regulation of cortisol secretion is further influenced by other hormones and/or cytokines, originating from the adrenal medulla or coming from the systemic circulation, and/or by neuronal signals via the autonomic innervation of the adrenal cortex
28. Glucocorticoids play a key regulatory role in the basal control of HPA axis activity and in the termination of the stress response, by acting at extrahypothalamic regulatory centers, the hypothalamus and the pituitary gland. The inhibitory glucocorticoid feedback on the ACTH secretory response acts to limit the duration of the total tissue exposure to ………glucocorticoids, thus minimizing the………… catabolic…………… lipogenic, antireproductive, …………..and immunosuppressive effects of these hormones.
30. Actions of glucocorticoids Two receptors Mineralocorticoid receptors Hippocampus and sensory and motor nuclei outside the hypothalamus Regulation of basal expression of ACTH, CRF and AVP Glucocorticoid receptors Hypothamic PVN, brainstem catecholaminergic cell groups, amygdala, hippocampus, pituitary Termination of the HPA axis response to stress
31. Actions of glucocorticoids Fetal organ maturation (esp. lungs) Metabolism (stimulates gluconeogenesis) Immune system (anti-inflammatory, immunosuppression) Maintain vascular tone
32. Arginine vasopressin (AVP) Arginine vasopressin (AVP) is a nonapeptide produced by parvocellular neurons of the PVN and by the magnocellular neurons of the neurohypophysis. While the AVP from the posterior pituitary is secreted into the circulation and modulates fluid and electrolyte homeostasis, AVP of PVN origin is secreted into the hypophyseal portal system, like CRH, and holds a key role in the response to stressors, being the second most important modulator of pituitary ACTH secretion. Whereas CRH appears to directly stimulate the ACTH secretion, AVP and other factors, such as angiotensin II, have primarily synergistic or additive effects.
33. The synergistic effect of AVP on the pituitary ACTH secretion offers an alternate pathway to influence the subsequent HPA axis activation at the hypothalamic level, since the secretion of CRH and AVP is further regulated by a variety of different neuropeptides, such as catecholamines which stimulate CRH secretion and ghrelin, a novel GH secretagogue factor, which appears to stimulate predominantly AVP secretion.
35. PVN CRH and AVP neurons also send projections to and activate pro-opiomelanocortin (POMC)-containing neurons in the arcuate nucleus of the hypothalamus. In turn, these POMC-containing neurons project reciprocally to the PVN CRH and AVP neurons, innervate LC/NE-sympathetic neurons of the central stress system in the brainstem and terminate on pain control neurons of the hind brain and spinal cord.
36. Thus, activation of the stress system, via CRH and catecholamines, stimulates the hypothalamic β-endorphin and other POMC-peptides secretion, which reciprocally inhibit the activity of the stress system, produce the "stress- induced" analgesia and may influence the emotional tone
37. Sympathetic/adrenomedullary and parasympathetic systems The autonomic nervous system provides a rapidly responsive mechanism to control a wide range of functions. Cardiovascular, respiratory, gastrointestinal, renal, endocrine, and other systems are regulated by either the sympathetic nervous system or the parasympathetic system or both. The modulation of the autonomic nervous system activity is generally achieved through a dual reaction, since the parasympathetic system can equally assist or antagonize most of the sympathetic functions by withdrawing or by increasing its activity, respectively.
38. Sympathetic innervation of peripheral organs is derived from the efferent preganglionic fibers whose cell bodies lie in the intermediolateral column of the spinal cord. These nerves synapse in the bilateral chain of sympathetic ganglia with postganglionic sympathetic neurons, which innervate widely the smooth muscle of the vasculature, the skeletal muscles, heart, kidney, gut, adipose tissue, and many other organs. The preganglionic neurons are primarily cholinergic, whereas the postganglionic neurons release mostly noradrenaline. The sympathetic system activity has an additional humoral contribution that comes from the circulating epinephrine and, to a lesser extent, norepinephrine released by the adrenal medulla, which can be considered as a modified sympathetic ganglion.
39. It must be noted that the regulatory actions of the autonomic nervous system activity involve a broader spectrum of neurotransmitters that complement the actions of acetylcholine and norepinephrine. Both the sympathetic and the parasympathetic system contain several subpopulations of target-selective and neurochemically coded neurons that express a variety of neuropeptides and, in some cases, adenosine triphosphate (ATP), nitric oxide, or lipid mediators of inflammation.
40. Interestingly, CRH, NPY, somatostatin, and galanin are colocalized in noradrenergic vasoconstrictive neurons, whereas vasoactive intestinal polypeptide (VIP) and, to a lesser extent, substance P (SP) and calcitonin gene-related peptide (CGRP) are colocalized in cholinergic neurons. Additionally, the signal transmission in sympathetic ganglia is further modulated by neuropeptides released from preganglionic fibers and short interneurons (e.g. enkephalin, neurotensin), as well as by primary afferent (e.g. substance P, VIP) nerve collaterals. Thus, the particular combination of neurotransmitters in sympathetic neurons is strongly influenced by central and local factors, which may trigger or suppress specific genes.
41. Mediators of Homeostasis and Stress Stress mediators, which include the classic neuroendocrine hormones of the stress system, but also several other neurotransmitters, cytokines and growth factors, regulate both basal and threatened homeostasis and might mediate the pathogenesis of dyshomeostasis-related diseases. Pivotal to our understanding of these mediators and their effects on the human organism in health and disease has been the above-mentioned concept of hypothalamic hypophysiotropic factors.
42. Central and Peripheral Effectors The principal, greatly interconnected CNS effectors of the stress system, include the hypothalamic hormones arginine vasopressin (AVP), corticotropin-releasing hormone (CRH), the pro-opiomelanocortin-derived peptides α-melanocyte-stimulating hormone and β-endorphin, and norepinephrine produced in the A1/A2 centers of the brainstem's locus ceruleus and in the central, autonomic nervous system.
43. other ascending aminergic pathways, such as the serotonergic pathways that originate from the midbrain (nuclei raphe) and the posterior hypothalamic histaminergic systems, accompany the locus ceruleus-derived norepinephrine central stress response through secretion of 5-hydroxytryptamine and histamine, respectively.
44. The principal peripheral effectors are glucocorticoids, which are regulated by the hypothalamic–pituitary–adrenal axis, and the catecholaminesnorepinephrine and epinephrine, which are regulated by the systemic and adrenomedullary sympathetic nervous systems. Interestingly, postganglionic sympathetic nerve fibers also secrete CRH, among other substances, whereas both catecholamines
45. stimulate interleukin (IL-) 6 release by immune cells and other peripheral cells via β-adrenergic receptors.Thetargets of all these stress mediators include the executive and/or cognitive, the fear/anger and reward systems, the wake–sleep centers of the brain, the growth, reproductive and thyroid-hormone axes, as well as the gastrointestinal, cardiorespiratory, metabolic, and immune systems.
46. Arousal and Sleep Activation of the stress system stimulates arousal and suppresses sleep;conversely, loss of sleep is associated with inhibition of the stress system. Interestingly, sleep loss is also associated with elevated level of circulating IL-6 in spite of the reduced stimulatory effect of catecholamines on IL-6 secretion; this change possibly results from the concurrently decreased cortisol-mediated inhibition
48. It is well-established that the activation of the LC/NE-noradrenergic and PVN CRH systems by stressors elevates the body core temperature.
49. Intracerebroventricular administration of both norepinephrine and CRH can cause temperature elevation, possibly through prostanoid-mediated actions on the septal and hypothalamic temperature-regulating center. CRH has also been shown to partly mediate the pyrogenic effects of the three major inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin 1 (IL-1), and interleukin-6 (IL-6), when stimulated by lipopolysaccharide, a potent exogenous pyrogen
50. Appetite-satiety centers - Appetite Regulation Stress is implicated in the regulation of appetite by influencing the central appetite-satiety centers in the hypothalamus. Acutely, CRH causes anorexia, whereas NPY, which is orexiogenic, stimulates CRH secretion, via Y1 receptors, probably to counter-regulate its own actions. Interestingly, at the same time, NPY inhibits the LC/NE-sympathetic system and activates the parasympathetic system, actions that decrease thermogenesis and help with digestion and storage of nutrients .
51. On the other hand leptin, the adipose tissue-derived satiety-stimulating hormone, inhibits the secretion of hypothalamic NPY, while it stimulates arcuate nucleus POMC neurons that secrete α-MSH, a potent anorexiogen and thermogenic peptide, which exerts its effects through specific melanocortin receptors type 4 (MC4)
52. Growth, Reproduction and Thyroid Function The growth, reproductive and thyroid-hormone axes are inhibited at several levels by stress mediators, whereas estradiol and thyroid hormones stimulate the stress system
53. Reproductive axis The reproductive axis is inhibited at all levels by various components of the HPA axis. CRH suppresses the gonadotropin hormone-releasing hormone (GnRH) neuron both directly and indirectly, via enhancing β-endorphin secretion by the arcuate POMC neurons. In addition glucocorticoids, exert inhibitory effects at the level of the GnRH neuron, the pituitary gonadotroph and the gonads themselves and additionally render target tissues of sex steroids resistant to these hormones.
54. Thus, steroidogenesis is directly inhibited at both ovaries and testes, with concomitant inhibition of the pulsatile secretion of the gonadotropin-releasing hormone from the hypothalamus. The latter effect is exerted both directly and by activating hypothalamic neural circuits that contain CRH and POMC, as well as by peripheral elevations of glucocorticoids. It is of note that, cytokines also suppress reproductive function at several levels
55. The interaction between CRH and the gonadal axis appears to be bidirectional. The presence of estrogen response elements in the promoter area of the CRH gene and direct stimulatory estrogen effects on CRH gene expression have been shown. This finding implicates the CRH gene and, therefore, the HPA axis as a potentially important target of ovarian steroids and a potential mediator of gender-related differences in the stress response/HPA axis activity.
56. On the other hand, the activated estrogen receptor interacts with and, on occasion, potentiates the c-jun/c-fosheterodimer, which mediates several cytokine effects. In addition, estrogen appears to stimulate adhesion molecules and their receptors in immune and immune accessory cells, thus offering a possible explanation as to why autoimmune diseases afflict frequently females than males
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58. Growth axis The growth axis is also inhibited at many levels during stress . Prolonged activation of the HPA axis leads to suppression of growth hormone secretion and inhibition of somatomedin C (SmC) and other growth factor effects on their target tissues by glucocorticoids , presumably via inhibition of the c-jun/c-fosheterodimer.
59. However, acute transient elevations of growth hormone concentrations in plasma may occur at the onset of the stress response in man, as well as after acute administration of glucocorticoids, presumably through GRE-stimulated growth hormone expression . In addition to the direct effects of glucocorticoids, which are pivotal in the suppression of growth observed in prolonged stress, increases in somatostatin secretion caused by CRH
60. , with resultant inhibition of growth hormone secretion, have also been implicated as a potential mechanism of stress-related suppression of growth hormone secretion . The redirection of nutrients and vital substrates to the brain and other areas where they are needed most during stress is the apparent teleology for the adverse effects of chronic stress on growth.
61. Thyroid axis A corollary phenomenon to growth axis suppression is the stress-related inhibition of thyroid axis function (Figure 5). Activation of the HPA axis is associated with decreased production of thyroid stimulating hormone (TSH) and inhibition of conversion of the relatively inactive thyroxine to the more biologically active triiodothyronine in peripheral tissues (the "euthyroid sick" syndrome) .
62. Although the exact mechanism(s) for these phenomena is not known, both phenomena maybe caused by the increased levels of glucocorticoids and theoretically serve a desired energy conservation during stress. Inhibition of TSH secretion by CRH-induced increases in somatostatin might also participate in the central component of thyroid axis suppression during stress. In the case of inflammatory stress, inhibition of TSH secretion and enhancement of somatostatin production may be in part through the action of cytokines on the hypothalamus and/or the pituitary
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64. Metabolism During acute stress, the heart rate and arterial blood pressure are increased, while gluconeogenesis, glycogenolysis, lipolysis and hepatic glucose secretion are stimulated, owing to elevated levels of catecholamines and cortisol
65. Stress system - Metabolism Glucocorticoids, the hormonal end-product of the HPA axis, exert primarily catabolic effects as part of a generalized effort to utilize every available energy resource against the challenge posed by intrinsic or extrinsic stressors. Thus, glucocorticoids increase hepatic gluconeogenesis and plasma glucose concentration, induce lipolysis (although they favor abdominal and dorsocervical fat accumulation) and cause protein degradation at multiple tissues (e.g. muscle, bone, skin) to provide amino acids that would be used as an additional substrate for oxidative pathways.
66. In addition to their direct catabolic actions, glucocorticoids also antagonize the beneficial anabolic actions of GH, insulin and sex steroids on their target tissues . This shift of the metabolism toward a catabolic state by the activated HPA axis normally reverses upon retraction of the enforced stressor. Chronic activation of HPA axis, however, would be damaging as it is expected to increase visceral adiposity, decrease lean body (muscle and bone) mass, suppress osteoblastic activity and cause insulin resistance (Figure 6
67. Interestingly, the phenotype of Cushing’s syndrome, characterized by abdominal and trunk fat accumulation and decreased lean body mass, in combination with manifestations of the metabolic syndrome (visceral adiposity, insulin resistance, dyslipidemia, hypercoagulability, hypercytokinemia, hypertension), is present in a variety of pathophysiologic conditions, collectively described as pseudo-Cushing’s states. This phenotype could be are presumably attributed to HPA-induced mild hypercortisolism or to peripheral tissue hypersensitivity to glucocorticoids .
68. This shift of the metabolism toward a catabolic state by the activated HPA axis normally reverses upon retraction of the enforced stressor. Chronic activation of HPA axis, however, would be damaging as it is expected to increase visceral adiposity, decrease lean body (muscle and bone) mass, suppress osteoblastic activity and cause insulin resistance (Figure 6). Interestingly, the phenotype of Cushing’s syndrome, characterized by abdominal and trunk fat accumulation and decreased lean body mass
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70. Gastrointestinal Function During stress, the gastrointestinal system is inhibited at the level of the stomach via the vagus nerve, while being stimulated at the level of the large bowel via the sacral parasympathetic system, which is activated by brainstem-derived norepinephrine
71. During acute stress, PVN CRH, independently of the associated stimulation of the HPA axis, induces both inhibition of gastric emptying and stimulation of colonic motor function by alterations in the autonomic nervous system activity . It is considered that inhibition of the vagus nerve activity at the dorsal vagal complex results in selective inhibition of gastric motility, while stimulation of the sacral parasympathetic system activity, possibly through CRH projections of the Barrington nucleus (which is part of the locus ceruleus complex) results in selective stimulation of colonic motility
72. . It is believed that, inhibition of gastric emptying involves the central medullary CRH-R2 receptors and possibly the peripheral CRH-R2 receptors at the gastrointestinal track, while the CRH-R1 subtype appears to mediate the colonic motor responses. Thus, CRH may be implicated in the gastric stasis that is associated with the stress of surgery or with high levels of central interleukin-1 as well as in the stress-induced colonic hypermotility of the irritable bowel syndrome.
73. Interestingly, the colonic contraction in patients with irritable bowel syndrome may activate the LC/sympathetic neurons, thus, forming a vicious cycle, which may help explain the chronicity of the condition. In addition to altering the motility pattern, stressors exert profound influences in several other aspects of the gastrointestinal function, as it has been found that the stress-induced activation of central and peripheral CRH receptors causes dysfunction of the intestinal barrier, increases gastrointestinal permeability and may enhance relapses of inflammatory bowel disease
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75. The Immune System Stress has complex effects on the immune system and influences both innate and acquired immunity. Glucocorticoids and catecholamines influence trafficking and/or function of leukocytes and accessory immune cells and suppress the secretion of proinflammatory cytokines (tumor necrosis factor [TNF], IL-1, IL-6, IL-8 and IL-12), whereas both hormone families induce a systemic switch from a TH1 response (that is, cellular immunity) to a TH2 response (humoral immunity).
76. Conversely, proinflammatory cytokines stimulate the stress system, also at multiple levels, in both the CNS and peripheral nervous system, including the hypothalamus, central noradrenergic system, pituitary and adrenal glands, which increases glucocorticoid levels and consequently suppresses the inflammatory reaction. These actions form another important negative-feedback loop that protects the organism from overshoot of the inflammatory response.
77. Peripheral secretion of 'authentic' CRH (originally described as 'immune' CRH because of its inflammatory actions) by postganglionic sympathetic neurons and norepinephrine-activated release of IL-6 by peripheral immune cells and other cells, respectively, lead to degranulation of mast cells (that is, the release of inflammatory and vasoactive molecules from their secretory vesicles) in several tissues and activates the sickness syndrome
78. The former action represents an important component of the neurogenic inflammatory response, whereas the sickness syndrome results from innate processes of the organism that are triggered and sustained by a systemic, inflammatory reaction. The syndrome includes somnolence, fatigue, nausea and depressive mood; these symptoms occur concurrently with activation of the acute-phase reaction by the liver and stimulation of the sensory-afferent nervous system, which manifests as hyperalgesia and fatigue.
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80. The hypothalamic-pituitary-adrenal (HPA) axis is the major endocrine stress axis of the human organism. Cortisol, the final hormone of this axis, affects metabolic, cardiovascular and central nervous systems both acutely and chronically.