1) Penile erection requires the coordinated interaction of the psychological, endocrine, neurologic, and vascular systems. Sexual stimulation leads to nitric oxide production which activates guanylate cyclase and cGMP, relaxing smooth muscles and causing vasocongestion and erection.
2) Erections can be genital, central-stimulated, or central-originated. The internal structure of the penis includes three corpora cavernosa and a spongiosum. Blood flow into the penis helps maintain erection by blocking venous outflow.
3) Relaxation of cavernous smooth muscle is key to erection. Nitric oxide and cGMP cause smooth muscle relaxation by opening potassium channels,
Anatomy of penis & physiology of erectionDeepesh Kalra
The penis has three cylindrical structures that create erections. During sexual stimulation, neurotransmitters are released that cause smooth muscle relaxation and dilation of arteries. This increases blood flow into the penis, compressing veins to trap blood and cause rigidity. Erection requires relaxation of sinusoidal spaces in the corpora cavernosa, dilation of arteries, and compression of veins. Both the autonomic and somatic nervous systems innervate the penis and play roles in sensations and rigid erections through pelvic plexus pathways and spinal cord regions. Various neurotransmitters and hormones systemically and locally influence flaccidity and erection.
This document summarizes the physiology of the urinary bladder and micturition reflex. It begins with the anatomical components of the bladder, including the body, trigone, internal sphincter, and external sphincter. It then describes the nerve supply to the bladder, including sympathetic, parasympathetic, and somatic nerves. The micturition reflex is a spinal reflex facilitated by higher brain centers that is initiated when urine fills the bladder and stretches its receptors, causing inhibition of the external urethral sphincter and allowing urination. Precise control of micturition involves a balance between inhibitory centers in the midbrain and cortex and facilitatory centers in the pons. Applied aspects discuss conditions like
1) The micturition reflex involves the filling and emptying of the bladder through neural pathways.
2) When the bladder fills with urine, stretch receptors in the bladder wall send signals through the pelvic nerve to the spinal cord. This causes the bladder to contract via parasympathetic fibers.
3) Contraction increases pressure in the bladder until a sustained pressure is reached, causing the urge to urinate. Voluntary control is exercised by the external urethral sphincter through inhibitory signals from the brain.
This document discusses the micturition reflex and various abnormalities that can occur with it. It begins by describing the normal process of micturition and transport of urine from the kidneys to the bladder. It then discusses how the bladder regulates filling and emptying through the micturition reflex. It describes two potential issues - vesicoureteral reflux which is backward flow of urine from the bladder into the ureters, and the ureterorenal reflex which is constriction of the renal arterioles in response to pain in the ureters. The document concludes by outlining several abnormalities that can occur with the micturition reflex, including atonic, automatic, dener
The vagus nerve is the 10th cranial nerve that has both motor and sensory components. It arises from the medulla and has an extensive distribution through the head, neck, thorax, and abdomen. It provides both parasympathetic output and visceral sensation. Some key functions include innervating the pharynx, larynx, heart, lungs, esophagus and stomach. Lesions can cause hoarseness of voice, dysphagia, or loss of gag reflex depending on the location along the nerve.
The document discusses the micturition reflex, which is the reflex by which the urinary bladder empties when full. It describes the physiological anatomy of the bladder, its innervation by sympathetic and parasympathetic nerves, and the normal pathway of the reflex from bladder filling to emptying. It also discusses some abnormalities in micturition that can occur due to deafferentation, denervation, or lesions disrupting control by higher brain centers.
The document summarizes the process of micturition (urination). It describes how urine is transported from the kidneys to the urinary bladder via ureters. As the bladder fills, stretch receptors send signals to the brain and spinal cord. When the bladder reaches capacity, the micturition reflex is triggered to relax the internal urethral sphincter and contract the detrusor muscle in the bladder wall to empty urine from the bladder through the urethra. Both voluntary and involuntary neural pathways in the brain, brainstem and spinal cord coordinate the filling and emptying of the bladder.
Anatomy of penis & physiology of erectionDeepesh Kalra
The penis has three cylindrical structures that create erections. During sexual stimulation, neurotransmitters are released that cause smooth muscle relaxation and dilation of arteries. This increases blood flow into the penis, compressing veins to trap blood and cause rigidity. Erection requires relaxation of sinusoidal spaces in the corpora cavernosa, dilation of arteries, and compression of veins. Both the autonomic and somatic nervous systems innervate the penis and play roles in sensations and rigid erections through pelvic plexus pathways and spinal cord regions. Various neurotransmitters and hormones systemically and locally influence flaccidity and erection.
This document summarizes the physiology of the urinary bladder and micturition reflex. It begins with the anatomical components of the bladder, including the body, trigone, internal sphincter, and external sphincter. It then describes the nerve supply to the bladder, including sympathetic, parasympathetic, and somatic nerves. The micturition reflex is a spinal reflex facilitated by higher brain centers that is initiated when urine fills the bladder and stretches its receptors, causing inhibition of the external urethral sphincter and allowing urination. Precise control of micturition involves a balance between inhibitory centers in the midbrain and cortex and facilitatory centers in the pons. Applied aspects discuss conditions like
1) The micturition reflex involves the filling and emptying of the bladder through neural pathways.
2) When the bladder fills with urine, stretch receptors in the bladder wall send signals through the pelvic nerve to the spinal cord. This causes the bladder to contract via parasympathetic fibers.
3) Contraction increases pressure in the bladder until a sustained pressure is reached, causing the urge to urinate. Voluntary control is exercised by the external urethral sphincter through inhibitory signals from the brain.
This document discusses the micturition reflex and various abnormalities that can occur with it. It begins by describing the normal process of micturition and transport of urine from the kidneys to the bladder. It then discusses how the bladder regulates filling and emptying through the micturition reflex. It describes two potential issues - vesicoureteral reflux which is backward flow of urine from the bladder into the ureters, and the ureterorenal reflex which is constriction of the renal arterioles in response to pain in the ureters. The document concludes by outlining several abnormalities that can occur with the micturition reflex, including atonic, automatic, dener
The vagus nerve is the 10th cranial nerve that has both motor and sensory components. It arises from the medulla and has an extensive distribution through the head, neck, thorax, and abdomen. It provides both parasympathetic output and visceral sensation. Some key functions include innervating the pharynx, larynx, heart, lungs, esophagus and stomach. Lesions can cause hoarseness of voice, dysphagia, or loss of gag reflex depending on the location along the nerve.
The document discusses the micturition reflex, which is the reflex by which the urinary bladder empties when full. It describes the physiological anatomy of the bladder, its innervation by sympathetic and parasympathetic nerves, and the normal pathway of the reflex from bladder filling to emptying. It also discusses some abnormalities in micturition that can occur due to deafferentation, denervation, or lesions disrupting control by higher brain centers.
The document summarizes the process of micturition (urination). It describes how urine is transported from the kidneys to the urinary bladder via ureters. As the bladder fills, stretch receptors send signals to the brain and spinal cord. When the bladder reaches capacity, the micturition reflex is triggered to relax the internal urethral sphincter and contract the detrusor muscle in the bladder wall to empty urine from the bladder through the urethra. Both voluntary and involuntary neural pathways in the brain, brainstem and spinal cord coordinate the filling and emptying of the bladder.
The process of voiding urine, known as micturition, involves the urinary bladder filling with urine and then emptying through contraction of the detrusor muscle and relaxation of the internal and external urethral sphincters. This is mediated by a micturition reflex initiated by stretch receptors in the bladder wall and regulated by spinal and brain centers. Voluntary control of micturition is achieved through inhibition or facilitation of the reflex by higher brain centers.
The document summarizes the anatomy and physiology of the urinary system and micturition process. It describes how urine is transported from the kidneys to the bladder through the ureters. It explains that the bladder stores urine through a balance of parasympathetic and sympathetic signals until reaching capacity, at which point a spinal micturition reflex is triggered to initiate voiding through coordinated detrusor contraction and urethral sphincter relaxation under control of the pontine micturition center. Higher brain centers can facilitate or inhibit micturition.
This document provides an overview of the nerve supply of the head and neck region. It begins with an introduction to the nervous system, including the central and peripheral nervous systems. It then discusses the 12 cranial nerves in detail, including their origin, course, structures supplied, and clinical correlations. For each cranial nerve, it provides summaries of key branches and their functions. The document also briefly discusses the spinal nerves and covers topics such as neurons, neuroglial cells, and the development of the nervous system. Overall, the document concisely summarizes the anatomy and clinical relevance of the major nerves involved in innervating the head and neck.
The urinary bladder is a hollow muscular organ that acts as a reservoir to store urine. During the filling phase, stretch receptors in the bladder wall signal the micturition reflex as the bladder fills past 250-400 ml. This initiates urination by contracting the detrusor muscle to void the bladder while relaxing the internal urethral sphincter. Higher brain centers can facilitate or inhibit the micturition reflex. Normal urination requires coordination between the micturition reflex and relaxation of the external urethral sphincter. Disorders of micturition can be non-neurogenic due to anatomical issues or neurogenic due to lesions affecting the central or peripheral nervous system that disrupt
The document summarizes the process of micturition, or urination. Micturition involves two main steps - the filling of the urinary bladder until tension reaches a threshold level, and then the emptying of the bladder through the micturition reflex or conscious decision. During emptying, the detrusor muscle in the bladder contracts while internal and external urethral sphincters relax, allowing urine to exit the body. The micturition reflex is controlled by the spinal cord, brain stem and cerebral cortex, and can be inhibited or initiated by higher brain centers.
The document discusses the parotid gland and facial nerve. It begins with an introduction to the parotid gland, noting that it is the largest serous salivary gland located in the cheek, deep to the ramus of the mandible. It then covers the anatomy of the parotid gland in detail, including its capsule, surfaces, borders, relations, contents, duct, nerve supply, lymphatic drainage and functions. The document then discusses the anatomy and branches of the facial nerve, including its nuclei, course through the skull base, branches within the parotid gland and associated ganglia. Clinical considerations related to the parotid gland and facial nerve palsy are also mentioned.
The document summarizes the physiology of micturition (urination). It discusses the anatomy of the ureters and bladder, as well as their innervation. It describes the mechanisms of bladder filling and emptying, including the micturition reflex. It also covers central control of micturition and applied aspects like spinal cord injuries. Recent advances discussed include the sensory role of non-neuronal cells in the bladder and potential new treatments.
The Endocrine System in the Head and NeckHadi Munib
The document discusses several endocrine glands in the head and neck region, including the pituitary gland, pineal gland, thyroid gland, and parathyroid glands. It provides details on the location, blood supply, nerve supply, and functions of each gland. It also describes the root of the neck and key muscles and vascular structures in that area, such as the scalene muscles, subclavian artery, and subclavian vein.
The document discusses the anatomy of the neck region. It describes the bones, muscles, fascia, vessels and nerves of the neck. Key points include:
- The neck is bounded by the mandible above and the clavicles below. It contains important structures like the larynx, trachea and esophagus.
- Major muscles include the sternocleidomastoid which divides the neck into anterior and posterior triangles.
- The deep cervical fascia supports neck structures and forms layers like the pretracheal and prevertebral fascia.
- Key blood vessels are the common carotid artery and its branches, the external and internal carotid arteries. The carotid sinus is a pressure receptor.
The vagus nerve is:
- The longest and most widely distributed of the cranial nerves.
- A mixed nerve that is mostly motor and innervates structures in the head, neck, thorax, and abdomen.
- Involved in motor function of the pharynx and larynx, and parasympathetic function like regulating heart rate and smooth muscle of organs.
- Assessed clinically by having a patient say "ah" and observing for symmetry of soft palate movement.
VAGUS NERVE AND ITS DESORDERS AND TREATMENTanand kumar
The vagus nerve is the longest cranial nerve. It interfaces with parasympathetic control of the heart, lungs, and digestive tract. It emerges from four nuclei in the medulla and travels through the neck and thorax to innervate organs. It controls functions like heart rate and gastrointestinal peristalsis. Symptoms of vagus nerve issues can include pain, organ dysfunction, fainting, difficulty swallowing, and changes in heart rhythm or vocal tone.
The document describes the anatomy of the brain and cranial nerves. It discusses the major structures of the brain including the cerebral cortex with its lobes, brain stem with midbrain, pons and medulla, and cerebellum. It then describes the 12 pairs of cranial nerves, identifying their origin, distribution and function. The cranial nerves include olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, spinal accessory, and hypoglossal nerves. Assessment techniques for cranial nerve function are also briefly outlined.
The document provides an overview of the arteries of the face. It notes that the face is supplied by branches of the external carotid artery including the facial artery, transverse facial artery, and maxillary artery. It also discusses the internal carotid artery and its terminal branch, the ophthalmic artery, which gives off the zygomaticofacial and dorsal nasal arteries that supply parts of the face. The anastomoses between the branches of the external and internal carotid arteries are mentioned as well.
The document discusses the anatomical structure and physiological function of the urinary bladder. It contains the following key points:
1. The urinary bladder is composed of the body, which contains the detrusor muscle responsible for emptying during urination, and the internal and external sphincters that prevent emptying.
2. During filling, the bladder adapts to increasing volume via relaxation, allowing large volumes with minimal pressure rise due to the law of Laplace.
3. Micturition is initiated by a reflex arc when filling reaches 300-400ml. Afferent signals travel to sacral micturition centers which excite detrusor contraction and inhibit sphincters, causing empty
The vagus nerve connects organs in the neck and below to the brainstem. It has both sensory and motor functions and helps control the heart rate, digestion, and other involuntary processes. Stimulation of the vagus nerve has been shown to reduce seizures, experimental pain, and inflammation, and may help treat conditions like epilepsy, obesity, and heart disease. Damage to the vagus nerve or its connections in the brainstem can impact swallowing, heart rate variability, and level of consciousness.
Anxiety and Physiological Symptoms of Panic Attacks final presentation avargas11
This document summarizes research on anxiety and panic attacks. It discusses neurological and genetic causes of panic attacks and factors that influence predisposition. Physiological symptoms are described for both spontaneous and induced panic attacks. The role of neuropeptides and neurotransmitters in regulating anxiety levels is also summarized. Finally, the document outlines areas for future research on directly studying symptomology and variables related to different levels of anxiety expression.
This document provides an overview of male reproductive physiology. It describes the major organs of the male reproductive system including the testes, ductular system, and penis. Key topics covered include spermatogenesis, the hormonal regulation of reproduction, and semen analysis. Common abnormalities such as cryptorchidism, hypogonadism, and Klinefelter syndrome are also discussed. The document uses diagrams and illustrations to enhance the explanations of anatomical structures and physiological processes involved in male reproduction.
Emotional Quotient (EQ) refers to one's ability to understand and manage emotions. It is comprised of self-awareness, social awareness, self-management, and relationship management. Traditionally, IQ was seen as the sole determinant of success, but it is now recognized that EQ plays an important role as well. Flexitime allows employees to choose their start and end times as long as they work a set number of hours during a core period each week. It can boost employee morale and productivity but may increase costs and cause communication issues.
The document discusses emotional intelligence (EQ) and its components. It explains that EQ involves self-awareness of one's own emotions and the emotions of others, self-management of emotions, and social skills. The five main components of EQ are identified as emotional self-awareness, managing emotions, using emotions to maximize thinking, developing empathy, and social skills. Further models and research on EQ are presented, including Goleman's competency model and studies on childhood development and EQ.
The process of voiding urine, known as micturition, involves the urinary bladder filling with urine and then emptying through contraction of the detrusor muscle and relaxation of the internal and external urethral sphincters. This is mediated by a micturition reflex initiated by stretch receptors in the bladder wall and regulated by spinal and brain centers. Voluntary control of micturition is achieved through inhibition or facilitation of the reflex by higher brain centers.
The document summarizes the anatomy and physiology of the urinary system and micturition process. It describes how urine is transported from the kidneys to the bladder through the ureters. It explains that the bladder stores urine through a balance of parasympathetic and sympathetic signals until reaching capacity, at which point a spinal micturition reflex is triggered to initiate voiding through coordinated detrusor contraction and urethral sphincter relaxation under control of the pontine micturition center. Higher brain centers can facilitate or inhibit micturition.
This document provides an overview of the nerve supply of the head and neck region. It begins with an introduction to the nervous system, including the central and peripheral nervous systems. It then discusses the 12 cranial nerves in detail, including their origin, course, structures supplied, and clinical correlations. For each cranial nerve, it provides summaries of key branches and their functions. The document also briefly discusses the spinal nerves and covers topics such as neurons, neuroglial cells, and the development of the nervous system. Overall, the document concisely summarizes the anatomy and clinical relevance of the major nerves involved in innervating the head and neck.
The urinary bladder is a hollow muscular organ that acts as a reservoir to store urine. During the filling phase, stretch receptors in the bladder wall signal the micturition reflex as the bladder fills past 250-400 ml. This initiates urination by contracting the detrusor muscle to void the bladder while relaxing the internal urethral sphincter. Higher brain centers can facilitate or inhibit the micturition reflex. Normal urination requires coordination between the micturition reflex and relaxation of the external urethral sphincter. Disorders of micturition can be non-neurogenic due to anatomical issues or neurogenic due to lesions affecting the central or peripheral nervous system that disrupt
The document summarizes the process of micturition, or urination. Micturition involves two main steps - the filling of the urinary bladder until tension reaches a threshold level, and then the emptying of the bladder through the micturition reflex or conscious decision. During emptying, the detrusor muscle in the bladder contracts while internal and external urethral sphincters relax, allowing urine to exit the body. The micturition reflex is controlled by the spinal cord, brain stem and cerebral cortex, and can be inhibited or initiated by higher brain centers.
The document discusses the parotid gland and facial nerve. It begins with an introduction to the parotid gland, noting that it is the largest serous salivary gland located in the cheek, deep to the ramus of the mandible. It then covers the anatomy of the parotid gland in detail, including its capsule, surfaces, borders, relations, contents, duct, nerve supply, lymphatic drainage and functions. The document then discusses the anatomy and branches of the facial nerve, including its nuclei, course through the skull base, branches within the parotid gland and associated ganglia. Clinical considerations related to the parotid gland and facial nerve palsy are also mentioned.
The document summarizes the physiology of micturition (urination). It discusses the anatomy of the ureters and bladder, as well as their innervation. It describes the mechanisms of bladder filling and emptying, including the micturition reflex. It also covers central control of micturition and applied aspects like spinal cord injuries. Recent advances discussed include the sensory role of non-neuronal cells in the bladder and potential new treatments.
The Endocrine System in the Head and NeckHadi Munib
The document discusses several endocrine glands in the head and neck region, including the pituitary gland, pineal gland, thyroid gland, and parathyroid glands. It provides details on the location, blood supply, nerve supply, and functions of each gland. It also describes the root of the neck and key muscles and vascular structures in that area, such as the scalene muscles, subclavian artery, and subclavian vein.
The document discusses the anatomy of the neck region. It describes the bones, muscles, fascia, vessels and nerves of the neck. Key points include:
- The neck is bounded by the mandible above and the clavicles below. It contains important structures like the larynx, trachea and esophagus.
- Major muscles include the sternocleidomastoid which divides the neck into anterior and posterior triangles.
- The deep cervical fascia supports neck structures and forms layers like the pretracheal and prevertebral fascia.
- Key blood vessels are the common carotid artery and its branches, the external and internal carotid arteries. The carotid sinus is a pressure receptor.
The vagus nerve is:
- The longest and most widely distributed of the cranial nerves.
- A mixed nerve that is mostly motor and innervates structures in the head, neck, thorax, and abdomen.
- Involved in motor function of the pharynx and larynx, and parasympathetic function like regulating heart rate and smooth muscle of organs.
- Assessed clinically by having a patient say "ah" and observing for symmetry of soft palate movement.
VAGUS NERVE AND ITS DESORDERS AND TREATMENTanand kumar
The vagus nerve is the longest cranial nerve. It interfaces with parasympathetic control of the heart, lungs, and digestive tract. It emerges from four nuclei in the medulla and travels through the neck and thorax to innervate organs. It controls functions like heart rate and gastrointestinal peristalsis. Symptoms of vagus nerve issues can include pain, organ dysfunction, fainting, difficulty swallowing, and changes in heart rhythm or vocal tone.
The document describes the anatomy of the brain and cranial nerves. It discusses the major structures of the brain including the cerebral cortex with its lobes, brain stem with midbrain, pons and medulla, and cerebellum. It then describes the 12 pairs of cranial nerves, identifying their origin, distribution and function. The cranial nerves include olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, spinal accessory, and hypoglossal nerves. Assessment techniques for cranial nerve function are also briefly outlined.
The document provides an overview of the arteries of the face. It notes that the face is supplied by branches of the external carotid artery including the facial artery, transverse facial artery, and maxillary artery. It also discusses the internal carotid artery and its terminal branch, the ophthalmic artery, which gives off the zygomaticofacial and dorsal nasal arteries that supply parts of the face. The anastomoses between the branches of the external and internal carotid arteries are mentioned as well.
The document discusses the anatomical structure and physiological function of the urinary bladder. It contains the following key points:
1. The urinary bladder is composed of the body, which contains the detrusor muscle responsible for emptying during urination, and the internal and external sphincters that prevent emptying.
2. During filling, the bladder adapts to increasing volume via relaxation, allowing large volumes with minimal pressure rise due to the law of Laplace.
3. Micturition is initiated by a reflex arc when filling reaches 300-400ml. Afferent signals travel to sacral micturition centers which excite detrusor contraction and inhibit sphincters, causing empty
The vagus nerve connects organs in the neck and below to the brainstem. It has both sensory and motor functions and helps control the heart rate, digestion, and other involuntary processes. Stimulation of the vagus nerve has been shown to reduce seizures, experimental pain, and inflammation, and may help treat conditions like epilepsy, obesity, and heart disease. Damage to the vagus nerve or its connections in the brainstem can impact swallowing, heart rate variability, and level of consciousness.
Anxiety and Physiological Symptoms of Panic Attacks final presentation avargas11
This document summarizes research on anxiety and panic attacks. It discusses neurological and genetic causes of panic attacks and factors that influence predisposition. Physiological symptoms are described for both spontaneous and induced panic attacks. The role of neuropeptides and neurotransmitters in regulating anxiety levels is also summarized. Finally, the document outlines areas for future research on directly studying symptomology and variables related to different levels of anxiety expression.
This document provides an overview of male reproductive physiology. It describes the major organs of the male reproductive system including the testes, ductular system, and penis. Key topics covered include spermatogenesis, the hormonal regulation of reproduction, and semen analysis. Common abnormalities such as cryptorchidism, hypogonadism, and Klinefelter syndrome are also discussed. The document uses diagrams and illustrations to enhance the explanations of anatomical structures and physiological processes involved in male reproduction.
Emotional Quotient (EQ) refers to one's ability to understand and manage emotions. It is comprised of self-awareness, social awareness, self-management, and relationship management. Traditionally, IQ was seen as the sole determinant of success, but it is now recognized that EQ plays an important role as well. Flexitime allows employees to choose their start and end times as long as they work a set number of hours during a core period each week. It can boost employee morale and productivity but may increase costs and cause communication issues.
The document discusses emotional intelligence (EQ) and its components. It explains that EQ involves self-awareness of one's own emotions and the emotions of others, self-management of emotions, and social skills. The five main components of EQ are identified as emotional self-awareness, managing emotions, using emotions to maximize thinking, developing empathy, and social skills. Further models and research on EQ are presented, including Goleman's competency model and studies on childhood development and EQ.
Test anxiety is a physiological condition causing extreme stress, anxiety, and discomfort before or during a test. It can be caused by poor study habits, lack of preparation, fear of failure, past poor test performances, worrying excessively prior to tests, and unrealistic expectations. Symptoms include physical issues like sweating and rapid heartbeat, emotional problems like crying or frustration, and cognitive difficulties like negative thinking and lack of concentration. To reduce test anxiety, one should lower stress, eat well, exercise, sleep enough, and be well prepared for exams.
The nervous system controls and coordinates the activities of the body. It has both voluntary and involuntary functions. The autonomic nervous system regulates involuntary functions like heart rate and digestion. It has two divisions - the sympathetic and parasympathetic systems which generally have opposing effects on organs. The sympathetic system prepares the body for fight or flight while the parasympathetic maintains normal functions. Dysfunctions of the autonomic nervous system can cause issues like high blood pressure, digestive problems, and more.
The nervous system controls and coordinates the activities of the body. It has both voluntary and involuntary functions. The autonomic nervous system regulates involuntary functions like heart rate and digestion. It has two divisions - the sympathetic and parasympathetic systems which generally have opposing effects on organs. The sympathetic system prepares the body for fight or flight while the parasympathetic maintains normal functions. Dysfunctions of the autonomic nervous system can cause issues like high blood pressure, digestive problems, and more.
Physiology of penile erection, pathophysiology evaluation & management of edPriyatham Kasaraneni
The document discusses the physiology of penile erection and the pathophysiology and management of erectile dysfunction. It covers the historical understanding of erection from ancient times through modern discoveries. Key points include that erection is caused by arterial inflow exceeding venous outflow due to relaxation of penile smooth muscle and compression of veins. Nitric oxide and phosphodiesterases play important roles. Erection involves reflex, psychogenic and nocturnal types triggered by various neural pathways and neurotransmitters like nitric oxide and endothelin.
Medical Information and treatment on Erectile Dysfunction and men's sexual health. A list of some of the available treatment solutions available to men who are suffering from blood flow issues and erectile dysfunction
The autonomic nervous system is divided into the parasympathetic and sympathetic divisions. The parasympathetic division activates rest and digest functions like increasing gastric secretions and the sympathetic division prepares the body for fight or flight through responses like increased heart rate. Both divisions use two neurons - a preganglionic neuron which terminates at a ganglion and a postganglionic neuron which innervates the target organ. The parasympathetic division originates in the brainstem and sacral spinal cord and the sympathetic division originates in the thoracic and lumbar spinal cord. Acetylcholine and norepinephrine act as the main neurotransmitters between neurons.
Erectile dysfunction is caused by problems with blood flow to the penis, nerve signals in the body, hormone levels, or psychological issues. During arousal, signals from the brain cause blood vessels in the penis to widen and let in more blood, making the penis hard. The veins are then compressed to maintain the erection. Common causes of erectile dysfunction include diseases like diabetes or damage to the nerves, blood vessels, muscles, or tissues of the penis. A doctor can diagnose erectile dysfunction through a medical history, physical exam, and tests. Treatments may include oral medications, counseling, injections, devices, or surgery.
This document discusses the anatomy, physiology, and pathophysiology of erectile dysfunction. It begins with the anatomy of the penis and details the structures involved in erection, including arteries, veins, nerves, and erectile tissue. It then discusses the physiology of the erectile process and factors involved in both attaining and maintaining an erection. It outlines various etiologies of erectile dysfunction including neurogenic, vasculogenic, hormonal abnormalities, medications, lifestyle factors, and aging.
This document summarizes the male sexual response cycle and the physiology underlying it. It describes the four phases of excitement, plateau, orgasm, and resolution. It discusses the nervous control and stimulation mechanisms involved in each phase. Specifically, it outlines the roles of the parasympathetic and sympathetic nervous systems in initiating erection and ejaculation respectively. It also briefly discusses disorders that can affect ejaculation such as premature ejaculation and retrograde ejaculation.
The document discusses the autonomic nervous system (ANS), which controls internal organs and glands. It describes the ANS as having two divisions - the sympathetic and parasympathetic systems. The sympathetic system activates the body's fight or flight response through secretion of epinephrine and norepinephrine from the adrenal medulla. The parasympathetic system acts to slow functions down and return the body to homeostasis. The document provides details on the pathways, targets, and functions of both divisions of the ANS.
The autonomic nervous system controls involuntary body functions and is divided into the sympathetic and parasympathetic nervous systems. The sympathetic system prepares the body for fight or flight through effects like increased heart rate and dilation of blood vessels. The parasympathetic system helps to rest and digest through effects like decreased heart rate and constriction of bronchioles. Both systems work in opposition to maintain homeostasis. Preganglionic neurons originate in the CNS and synapse with postganglionic neurons in autonomic ganglia which connect to effector organs. Acetylcholine and norepinephrine are important neurotransmitters that allow the autonomic nervous system to regulate vital involuntary functions.
The autonomic nervous system regulates the body's internal environment and physical exchanges with the external environment, along with the endocrine system, to maintain homeostasis. It has two divisions - the sympathetic and parasympathetic systems. The central ANS is diffuse in the brain and spinal cord and controls the peripheral ANS neurons and organs. The peripheral ANS includes neurons that release neurotransmitters like acetylcholine and norepinephrine at targets like smooth muscle, cardiac muscle and glands to produce effects like increasing heart rate and relaxing bronchial muscles during the fight or flight response.
The document provides an overview of the sympathetic and parasympathetic nervous systems. It discusses the structural organization and functions of each system. The sympathetic system is activated during fight or flight responses and increases heart rate, blood pressure, respiration and mobilizes energy stores. It is organized with cell bodies in the spinal cord that project to ganglia. The parasympathetic system counteracts the sympathetic responses and is organized with cell bodies in the brainstem and sacral cord that project to target organs. Both systems use acetylcholine as a neurotransmitter but target different receptor types to produce their effects.
The document summarizes key aspects of the autonomic nervous system, with a focus on the sympathetic and parasympathetic divisions. It describes:
- The autonomic nervous system regulates involuntary body functions and contains the sympathetic and parasympathetic nervous systems.
- The sympathetic nervous system activates the body's fight or flight response through neurons in the spinal cord, increasing heart rate, blood pressure, and diverting blood flow away from the digestive system.
- The parasympathetic nervous system calms the body and activates the rest and digest response through cranial and sacral nerves, lowering heart rate and stimulating digestion.
The urinary bladder consists of a body that collects urine and a neck that connects to the urethra. The smooth muscle of the bladder is called the detrusor muscle. The trigone area on the posterior bladder wall contains the openings of the ureters and bladder neck. Innervation involves parasympathetic fibers that cause bladder contraction and sympathetic fibers that stimulate blood vessels. During filling, stretch receptors trigger micturition reflexes in the spinal cord, and higher brain centers facilitate or inhibit emptying. Spinal cord injuries can cause various types of neurogenic bladder depending on the level and completeness of the lesion.
The document provides an overview of the physiology of the autonomic nervous system (ANS). It discusses the history and definitions of the ANS, as well as the anatomy and functions of the sympathetic and parasympathetic nervous systems. Specifically, it describes how the sympathetic nervous system is involved in the "fight or flight" response while the parasympathetic nervous system governs "rest and digest" functions. It also summarizes the autonomic innervation of the heart.
Perception involves awareness of sensory stimuli through mental processes like memory and interpretation. Coordination requires perception of necessary movements and completion of actions via muscles working together. The central nervous system, peripheral nervous system, autonomic nervous system, and neuroendocrine system control coordination and perception. [Neurons, neuroglia, neurotransmitters, and nerves are the basic structures involved. The brain and spinal cord make up the central nervous system. The peripheral nervous system includes cranial and spinal nerves. The autonomic nervous system regulates involuntary functions and has sympathetic and parasympathetic divisions.]
3. An Erection Requires a Coordinated
Interaction of Multiple Organ Systems
Psychological
Endocrine
Neurologic
Vascular
4. Physiology of penile erection
Sexual stimulation Nitrix oxide synthesized in nerve
and vascular tissue of penis
Nitrix oxide activates
GTP cGMP guanylate cyclase
cGMP relaxes smooth muscles of Vasocongestion of
corpus cavernosum/penile arterioles penile tissues
17
5. Three types of erections
1. Genital stimulated (contact or reflexogenic)
- induced by tactile stimulation of the genital area.
- can be preserved in upper spinal cord lesions.
- usually short in duration and poorly controlled .
2.central-stimulated (noncontact or psychogenic)
- more complex,
- resulting from memory, fantasy, visual, or auditory stimuli.
3. central-originated (nocturnal)
- can occur spontaneously without stimulation or during
sleep
- most sleep erections occur during REM sleep.
- occurs due to differential activation of cholinergic neurons
at RAS while deactivation of adrenergic and serotonergic neurons
during REM sleep.
.
6. Internal structure of the penis: top view
(internal, in
(between glans and the body) pelvic cavity)
Male Sexual Anatomy (cont.)
(engorge with blood
(head of the (expands during arousal)
penis; lots of to form
nerve endings) the glans)
Fig 5.1a Interior structure of the penis: (a) view from above.
7. cross-section of the penis
Tube within tube pattern.
Three corpora
Thick bilayered T.albuginia with
elastic fibers which can expand
and strech.
Incomplete outer longitudinal
layer b/w 5-7 0’clock.
Spongiosa lacking outer long.
Layer of T. albuginea.
Intracavernosal pillars and
incomplete incavernosal septum.
suspended to lower ischiopubic
ramii through fundiform and
suspensory ligaments.
9. Hemodynamics of Erection
In the flaccid state, the arteries, arterioles, and sinusoids are contracted.
The intersinusoidal and subtunical venous plexuses are wide open, with free
flow through the emissary veins. The pO2 is venous(35 mm Hg).
In the erect state, the muscles of the sinusoidal wall and the arterioles relax,
allowing maximal flow to the compliant sinusoidal spaces.
Most of the venules are compressed b/w expanding sinusoids. Larger
venules of sub tunicial plexus are sandwiched b/w the distended sinusoids
and the t.albuginea that effectively reduces the venous capacity to a
minimum. The pO2 here is arterial(> 90 mm Hg) and ICP >100mmHg.
10. How blood inflow helps maintain
erection
Inside the penis: like a tube within a tube
When the inner tube fills with blood and expands,
it fills the space between the tubes and blocks the
outflow of blood, helping to maintain erection.
11. Phases of the Erection Process
(o) Flaccid phase
Minimal arterial and venous flow; blood gas values equal
those of venous blood.
(1) Latent (filling) phase
Increased flow in the internal pudendal artery during both
systolic and diastolic phases. Decreased pressure in the
internal pudendal artery; unchanged intracavernous
pressure. Some elongation of the penis.
(2) Tumescent phase
Rising intracavernous pressure until full erection is achieved.
arterial flow rate decreases as the pressure rises.
When intracavernous pressure rises above diastolic pressure,
flow occurs only in the systolic phases.
12. Phases of the Erection Process
(3) Full erection phase
Intracavernous pressure rises to as much as 80–90% of the systolic pressure.
Pressure in the artery increases but remains slightly below systemic pressure.
Arterial flow is much less than in the initial filling phase but is still higher than
flaccid phase.
The venous channels are mostly compressed.
Blood gas values approach those of arterial blood.
(4) Skeletal or rigid erection phase
As a result of contraction of the ischiocavernous muscle,
the intracavernous pressure rises well above the systolic pressure, resulting in
rigid erection.
almost no blood flows through the cavernous artery.
(5) Initial detumescent phase
After ejaculation or cessation of erotic stimuli, sympathetic discharge resumes,
contraction of the smooth muscles around the sinusoids and arterioles.
(5) Slow detumescent phase – slow opening of venous channels.
(6) Fast detumescent phase
Expelulsion of a large portion of blood from the sinusoidal and diminition of the
arterial flow to flaccid leve. The penis returnsto its flaccid length and girth
14. Neurophysiology of Erection
Peripheral and spinal
At glans penis, high density free nerve endings and
receptors.
Dorsal nerve of penis carries somatosensory fibers.
Sympathetic innervation from T10-T12 segments.
causes detumescence.
Parasympathetic supply through cavernous nerve from
pelvic plexus carrying S2-4segments.induces erection.
Pudendal nerve from Onuf’s nucleus(S2-4) is
somatomotor, supplying muscles.
Contraction of the ischiocavernosus muscles produces
the rigid-erection phase. Rhythmic contraction of the
bulbocavernosus muscle helps in ejaculation.
15. Neurophysiology of Erection contd .
Supraspinal centers
Medial Pre Optic Area (MPOA) and paraventricular nucleus
(PVN) of the hypothalamus and hippocampus are important
integration centers for sexual function and penile erection
( Sachs and Meisel, 1988 ; Marson et al, 1993 )
Medial preoptic area (MPOA) recognizes a sexual partner
and integrate hormonal and sensory cues.
Efferent pathways from the MPOA passes through the
medial forebrain bundle and the midbrain tegmental region.
Pathologic processes in these regions, such as PD or CVA,
are often associated with ED.
Paraventricular nucleus (PVN) facilitates penile erection
through oxytocin neurons to spinal sympathetic efferents –
Psychogenic erection that persist even in lumbar and
sacral cord injuries.
16. Spinal Reflexes Involved in Stimulation of Penile
Dorsal Nerve
Stimulation Spinal Center Efferent Effect
Noxious, abrupt Sacral motor Pudendal nerve Bulbocavernous
stimulation neurons (motor) reflex
Low-intensity Sacral 1. Pelvic nerves 1.Closure of
continuous (e.g., parasympathetic bladder neck and
vibratory, manual) neurons and Bladder inhibition
interneurons 2. Cavernous 2. Penile erection
nerve
High-intensity Sacral motor and Pudendal, pelvic, Ejaculation
continuous parasympathetic and cavernous
Thoracolumbar nerves
sympathetic
neurons
18. Neurotransmitters
Peripheral Neurotransmitters
Adrenergic neurotransmission, and endothelium-
derived contracting factors such as angiotensin II,
PGF2α, and endothelins maintain the flaccid state.
NO released from nonadrenergic, noncholinergic
neurotransmission and from the endothelium is the
principal neurotransmitter mediating penile erection.
NO increases the production of cGMP, which in turn
relaxes the cavernous smooth muscle.
Detumescence after erection may be a result of
cessation of NO release, the breakdown of cyclic
guanosine monophosphate (cGMP) by
phosphodiesterases, or sympathetic discharge during
ejaculation.
19. Neurotransmitters
Central Neurotransmitters
Dopaminergic and adrenergic receptors promote sexual
function. (Apomorphine / Yohimbine)
Serotonin inhibit sexual drive. (SRI /Buspirone)
Low levels of DA stimulation causes erection (D1) while higher
levels or prolonged stimulation produces seminal emission
( D2 ).Act through Oxytocin release from PVA.
Prolactin suppress sexual function through inhibition of
dopaminergic activity in the MPOA and decreased testosterone.
has a direct contractile effect on the cavernous smooth muscle.
GABA, NO, Opioids and melanocortins are other modulators.
21. Physiology of
Smooth Muscle Relaxation
▪ Relaxation of the cavernous smooth muscle is the key to penile erection.
▪ Low cytosolic calcium favors smooth muscle relaxation.
▪ Nitric oxide released by nNOS contained in the terminals of the
cavernous nerve initiates the erection process, and nitric oxide released
from eNOS in the endothelium helps maintain erection.
▪ Upon entering the smooth muscle cells, NO stimulates the production of
cGMP.
PGE1and PGE2 activate adenyl cyclase to produce cAMP.
▪ Cyclic GMP and AMP activate protein kinases A & G , which in turn
opens potassium channels and closes calcium channels and
sequestration of intracellular Ca by EPR.
The resultant fall in intracellular calcium leads to smooth muscle
relaxation.
▪ The smooth muscle regains its tone when cGMP and cAMP are
degraded by phosphodiesterase and it leads to detumesence.
PDE5 is the principle phosphodiesterase that is inhibited by Sildenafil.
Papaverine is a nonspecific phosphodiesterase inhibitor.
22.
23. Ejaculation
Ejaculation: the process by which semen is expelled
through the penis outside the body.
Ejaculation is a separate process from orgasm, and
the two may not always occur simultaneously.
It is possible for men to experience multiple orgasms w/o
ejaculation.
2 phases (see next slides for details):
1) Emission phase: semen collects in the urethral bulb
This stage is usually sensed by the man as the
“point of no return”
2) Expulsion phase: semen is expelled
24. Emission phase of ejaculation (phase 1)
Contractions in the prostate, seminal vesicles, and vas
deferens force secretions into urethral bulb.
Both the internal and external urethral sphincters close,
trapping semen in the urethral bulb
(like a balloon)
25. Expulsion phase of ejaculation (phase 2)
Collected semen is expelled out of the body by rhythmic
contractions of muscles surrounding the urethral bulb and also
on the urethra.
External urethral sphincter relaxes to allow semen out; internal
urethral sphincter stays contracted to prevent the escape of
urine.
27. Definitions
Erectile dysfunction is defined as the
“Inability to achieve or maintain an erection
sufficient for satisfactory sexual performance.”
-The National Institutes of Health (NIH) Consensus Development
Conference on Impotence(December 7-9, 1992)
28. ED vs Impotence
“ED is the more precise term, especially
given the fact that sexual desire and the
ability to have an orgasm and ejaculate may
well be intact despite the inability to achieve
or maintain an erection.”
- American Urological Association Education and Research
30. Incidence and prevalance
Incidence of 25 to 30 per 1000 man-years
-Moreira et al, 2003 ; Schouten et al, 2005
Age dependent
2%men at age <40 years
25% men age 65
75% men >75 years
-Kinsey et al ,1948
Not a necessary occurrence of the aging process
Rising trend of prevalance of ED
-international studies reported between 1993 and 2003
31. Massachusetts Male Aging Study (MMAS)
Prevalence rates of ED between the ages of 40 and
70 years, the probability of complete ED increased
from 5.1% to 15%, moderate dysfunction increased
from 17% to 34%, and mild dysfunction remained
constant at about 17%.
Crude incidence rate of impotence in white men in
the United States was 25.9 cases per 1000 man-
years.
ED was higher for men with diabetes mellitus (50.7
cases), treated heart disease (58.3 cases), and
treated hypertension (42.5 cases) per 1000 man-
years.
32. Risk Factors
Diabetes 27% - 59%
Chronic renal failure 40%
Hepatic failure 25% - 70%
Multiple Sclerosis 71%
Severe depression 90%
Other (vascular disease, low HDL, high
cholesterol)
-Benet et al. Urol Clinic North Am. 1995; 151:54-61
33. Other risk factors
General health status
Concurrence of other genitourinary disease
Psychiatric or psychologic disorders
Other chronic diseases
Sociodemographic conditions.
Smokingng and medications
Hormonal factors
Endothelial dysfunction - common etiologic pathway
37. Psychogenic ED
Sexual behavior and penile erection are controlled
by the hypothalamus, the limbic system, and the
cerebral cortex.
Direct inhibition of the spinal erection center by the
brain as an exaggeration of the normal suprasacral
inhibition ( Steers, 1990 )
Excessive sympathetic outflow or elevated
peripheral catecholamine levels, which may
increase penile smooth muscle tone to prevent its
necessary relaxation (Kim and Oh,1992)
38. Classification of ED
International society of Impotence Research
Psychogenic ED
1. Generalized type
A. Generalized unresponsiveness
a. Primary lack of sexual arousability
b. Aging-related decline in sexual arousability
B. Generalized inhibition
a. Chronic disorder of sexual intimacy
2. Situational type
A. Partner related
a. Lack of arousability in specific relationship
b. Lack of arousability due to sexual object preference
c. High central inhibition due to partner conflict or threat
B. Performance related
a. Associated with other sexual dysfunction/s (rapid ejaculation)
b. Situational performance anxiety (eg, fear of failure)
C. Psychological distress or adjustment related
a. Associated with negative mood state (eg, depression)
b. major life stress (eg, death of partner)
39. Differentiating Psychogenic
from Organic ED
Psychogenic ED:
Younger patient (<40)
Preservation of morning erections and
nocturnal erections
Achieve erection with masturbation
May be partner-specific
Often sudden onset
41. Differentiating Psychogenic from
Organic ED
Organic ED:
Gradual deterioration
Decrease in morning erections and nocturnal
erections
No erections with masturbation
No loss of libido
Presence of co-morbid conditions
42. Classification of ED
International society of Impotence Research
Organic ED
1. Neurogenic
2. Hormonal
3. Arterial
4. Cavernosal (venogenic)
5. Drug induced
43. Neurogenic
10% to 19% of ED is neurogenic ( Abicht 1991 ;
Aboseif et al, 1997 ).
Pathologic processes in the region of higher center,
such as Parkinson's disease, stroke, encephalitis, or
temporal lobe epilepsy ,tumors, dementias,
Alzheimer's disease, and trauma .
Spinal cord injuries: 5% - 80%
Reflexogenic erection is preserved in 95% of patients
with complete upper cord lesions but in only about
25% of those with complete lower cord lesions.
( Eardley and Kirby, 1991 ).
disorders at the spinal level e.g., spina bifida, disk
herniation, syringomyelia, tumor, transverse myelitis,
and multiple sclerosis
Injury to cavernosal nerve and pelvic plexus in pelvic
surgery ( Iatrogenic ED)
44. Iatrogenic impotence resulting from
various pelvic surgical procedures
radical prostatectomy - 43% to 100%
Nerve sparing radical prostatectomy
-30% to 50%
perineal prostatectomy for benign disease
- 29%
abdominal perineal resection
-15% to 100%
external sphincterotomy at the 3 and 9
o'clock positions -2% to 49%
45. Hormonal
Hypogonadism is a not-infrequent finding in the impotent
population.
Testosterone enhances sexual interest, increases the
frequency of sexual acts, and increases the frequency of
nocturnal erections but has little or no effect on fantasy-
induced or visually stimulated erections.
However, exogenous testosterone therapy in impotent men
with borderline-low testosterone levels reportedly has little
effect ( Graham and Regan, 1992 ).
Hyperprolactinemia,results in both reproductive and sexual
dysfunction and is associated with low circulating levels of
testosterone, which appear to be secondary to inhibition of
gonadotropin-releasing hormone secretion by the elevated
prolactin levels.
In hypothyroidism, low testosterone secretion,increased
circulating estrogen and elevated prolactin levels contribute
to ED.
46. Arteriogenic
Atherosclerotic or traumatic arterial occlusive disease
of the hypogastric-cavernous-helicine arterial tree can
decrease the perfusion pressure and arterial flow to
the sinusoidal spaces,
This increases the time to maximal erection and
decreases the rigidity of the erect penis.
An atherosclerotic process may decrease expansibility
of cavernous smooth muscles by decreasing NOS
activity.
Common risk factors associated with arterial
insufficiency include hypertension, hyperlipidemia,
cigarette smoking, diabetes mellitus, blunt perineal or
pelvic trauma, and pelvic irradiation.
As, ED and cardiovascular disease share the same
risk factors, ED may present as a manifestation of
generalized or focal arterial disease (Sullivan et
al,1999).
47. Cavernous (Venogenic)
Failure of adequate venous occlusion is one of the
most common causes of vasculogenic impotence
( Rajfer et al, 1988 ).
Veno-occlusive dysfunction : degenerative tunical
changes, fibroelastic structural alterations (increased
deposition of collagen and decreased elastic fiber) ,
insufficient trabecular smooth muscle relaxation, and
venous shunts.
Degenerative changes as old age, and diabetes or
traumatic injury to the tunica albuginea (penile
fracture) can impair the compression of the subtunical
and emissary veins.
In Peyronie's disease, the inelastic tunica albuginea
may prevent the emissary veins from closing. ( Metz et
al, 1983 ).
48. Diabetes and ED
The prevalence of ED is three times higher in diabetic men
(28% versus 9.6%) ( Feldman et al, 1994 ), occurs at an
earlier age, and increases with disease duration.
Associated with a decreased desire and orgasmic
dysfunction as well .
ED occurs due to dysfunction of one or a combination of :
psychologic function, CNS function, androgen secretion,
peripheral nerve activity, endothelial cell function, and
smooth muscle contractility ( Dunsmuir and Holmes, 1996 ).
A higher odds ratio is seen with insulin-dependent diabetes
mellitus; diabetes present for over 10 years; fair or poor
control based on glycosylated hemoglobin; management by
means other than diet; a history of diabetes-related arterial,
renal, or retinal disease and neuropathy; and concurrent
cigarette smoking.
49. Drug induced ED
Most common cause of ED in men >50 years.
Antihypertensives
- thiazides
- β- Blockers
- α1 blockers
- α2 agonist
- ACE inhibitor and AT II antagonists
Antipsychotics
Antidepressants.
-Tricyclics
- Monoamine oxidase inhibitors
- Selective serotonin reuptake inhibitors (SSRIs)
Anxiolytics
Antiandrogens
Digitalis
Opioids
Protase inhibitors
Tobbaco and alcohol
H2 receptor antagonist