This document provides an overview of bone tissue and the skeletal system. It discusses the key functions of bone, the major tissues of the skeletal system including bone, cartilage, periosteum and endosteum. It describes the structure of long bones and the histology of compact and spongy bone. Bone formation occurs through two processes, intramembranous and endochondral ossification. Bone growth and remodeling requires balanced activity of osteoblasts and osteoclasts and is regulated by minerals, vitamins and hormones like PTH, calcitonin, growth hormone and sex hormones. Calcium homeostasis in the body is maintained through hormonal control of calcium levels in the blood and bone.
This document is an interactive presentation about cyberbullying. It defines cyberbullying, provides examples of forms it can take like texts, messages and social media. It asks the reader questions to self-reflect if they have engaged in cyberbullying and what to do if they find out a friend is bullying. It stresses telling a trusted adult if being bullied and having online etiquette to prevent harming others online. The presentation includes a quiz to test understanding of proper responses and stresses consequences of cyberbullying. It provides resources to learn more about preventing and addressing cyberbullying issues.
The document lists various common health problems and their symptoms in both English and Thai. It includes conditions such as allergies, coughs, dizziness, fever, insomnia, rashes, runny noses, sunburn, headaches, stomachaches, earaches, toothaches, cuts, cramps, bruises, sore throats, broken bones, colds, stuffy noses, and blisters. It also provides examples of how to describe something being sore, bad, or aching by combining those words with body parts or areas.
This document provides an overview of bone tissue and the skeletal system. It discusses the key functions of bone, the major tissues of the skeletal system including bone, cartilage, periosteum and endosteum. It describes the structure of long bones and the histology of compact and spongy bone. Bone formation occurs through two processes, intramembranous and endochondral ossification. Bone growth and remodeling requires balanced activity of osteoblasts and osteoclasts and is regulated by minerals, vitamins and hormones like PTH, calcitonin, growth hormone and sex hormones. Calcium homeostasis in the body is maintained through hormonal control of calcium levels in the blood and bone.
This document is an interactive presentation about cyberbullying. It defines cyberbullying, provides examples of forms it can take like texts, messages and social media. It asks the reader questions to self-reflect if they have engaged in cyberbullying and what to do if they find out a friend is bullying. It stresses telling a trusted adult if being bullied and having online etiquette to prevent harming others online. The presentation includes a quiz to test understanding of proper responses and stresses consequences of cyberbullying. It provides resources to learn more about preventing and addressing cyberbullying issues.
The document lists various common health problems and their symptoms in both English and Thai. It includes conditions such as allergies, coughs, dizziness, fever, insomnia, rashes, runny noses, sunburn, headaches, stomachaches, earaches, toothaches, cuts, cramps, bruises, sore throats, broken bones, colds, stuffy noses, and blisters. It also provides examples of how to describe something being sore, bad, or aching by combining those words with body parts or areas.
This document discusses promoting health in older adults. It begins by defining aging and categorizing the aging population. It then outlines different care settings for elders, including acute care facilities, long-term care facilities, hospice, rehabilitation, and community settings. It also discusses common biologic theories of aging and physiological changes associated with aging, including changes to the integumentary, neurological, musculoskeletal, sensory, pulmonary, cardiovascular, gastrointestinal, urinary, immunological, and endocrine systems. Finally, it covers psychosocial theories of aging and developmental tasks of aging.
The document provides instructions for students to create and perform a drama piece based on the story of cyberbullying. It involves multiple steps: 1) Creating freeze frames showing scenarios of cyberbullying; 2) Devising and performing a scene showing the consequences of cyberbullying decisions; 3) Rehearsing and performing a scripted scene between a cyberbully and her victim; 4) Creating and performing a flashback scene showing why the cyberbullying began. The document provides assessment criteria for performance skills and directs students to plan and film their work to present the completed drama piece assessing their exploration of the impacts of cyberbullying.
8 million women and 2 million men in the US are diagnosed with osteoporosis. The document discusses the history of defining and diagnosing osteoporosis and osteopenia, and how drug companies worked to expand the definition of osteopenia to increase the market for osteoporosis drugs like Fosamax. Long term use of Fosamax has been linked to spontaneous bone fractures through impaired bone healing. Lifestyle factors like exercise, diet, and vitamin D can help promote strong bones.
The document discusses health promotion and the roles of pharmacists. It defines health promotion as enabling people to control and improve their health through skills and environmental changes. Pharmacists are well-positioned to conduct health promotion activities due to their accessibility and knowledge. The document outlines various health promotion strategies pharmacists can implement, such as providing educational materials, hosting displays, and taking opportunities during medicine sales to discuss health topics.
The parathyroid glands are four small glands located behind the thyroid gland, with one at each end of the upper and lower poles of the thyroid. The glands consist of two main cell types: chief cells and oxyphil cells. Chief cells are small polygonal cells that synthesize and secrete parathyroid hormone, which regulates blood calcium levels. Oxyphil cells are larger than chief cells and less numerous.
House dust mites are a major cause of asthma, allergic rhinitis, and atopic dermatitis. The two most common house dust mite species worldwide are Dermatophagoides pteronyssinus and Dermatophagoides farinae. House dust mites thrive in warm, humid environments and their allergens are found in dust in homes and can become airborne, easily being inhaled and triggering allergic reactions in sensitized individuals. Diagnosis of house dust mite allergy involves tests to detect house dust mite-specific IgE antibodies such as enzyme immunoassays. Preventive measures focus on reducing indoor humidity and house dust mite allergen levels through methods such as mattress
The document discusses the history and causes of allergies. It notes that allergy rates have tripled over the last 20 years. Potential causes discussed include the hygiene hypothesis (decreased exposure to bacteria), vaccinations, toxic food proteins from GMOs and preservatives, and genetics. Specific food additives and preservatives like sodium benzoate, sodium nitrate, and MSG are highlighted as potentially increasing health risks such as cancer and neurological diseases. The impacts of a lack of gut bacteria diversity from excessive antibiotic use and a lack of exposure to microorganisms are also discussed in relation to the hygiene hypothesis.
Cyberbullying involves intentionally and repeatedly harming others online through technologies like cell phones and social media. It can make victims feel sad, angry, or afraid. Common forms of cyberbullying include mean posts, messages, photos, or videos that are shared and spread widely. While some kids can handle cyberbullying, it has led some teens to depression and even suicide. Laws are being passed to help prevent cyberbullying and punish those who engage in it.
The document discusses wound classification and the normal process of wound healing. It defines wounds and classifies them into four categories (clean, clean-contaminated, contaminated, dirty/infected) based on the CDC's adaptation of the American College of Surgeons' wound classification schema. It then describes the four phases of normal acute wound healing: hemostasis, inflammation, proliferation, and remodeling. Hemostasis involves platelet aggregation and fibrin clot formation to stop bleeding. Inflammation brings neutrophils and macrophages to remove debris. Proliferation involves new tissue formation. Remodeling shapes the new tissue.
Health education aims to promote, maintain, and restore health. It involves educating individuals and groups on behaviors that improve health. Effective health education requires strong communication skills. Using audiovisual aids can make health education messages more clear, organized, and impactful as they allow concepts to be demonstrated and reinforced in a memorable way. Audiovisual aids also help match different learning styles and convey messages with less effort.
this is presentation talks about basic & updated advanced wounds care,,,,,,,2nd presentation in my internship..i hope you will get benefit from it ......Dr/ Wadie Madi
The document discusses cyber bullying and provides advice on preventing and responding to it. It defines cyber bullying as using technology like mobile phones or the internet to deliberately upset someone. It emphasizes the importance of having a shared understanding of cyber bullying across the school community and reviewing policies. Key steps to preventing cyber bullying include educating students on safe technology use, providing reporting methods, and using technology to promote self-esteem and relationships. Responding involves supporting the target, investigating, working with the bully, and potentially involving service providers or police.
The presentation is for the use of Physiotherapy students. It covers a brief introduction, classification, clinical features and general principles of management.
The document discusses various anxiety disorders and their treatment. It describes several anxiety disorders in detail, including generalized anxiety disorder, panic disorder, post-traumatic stress disorder, specific phobias, social anxiety disorder, and obsessive-compulsive disorder. It examines biological, psychological, and behavioral factors that may contribute to the development and maintenance of anxiety disorders. Finally, it reviews both biological and psychological treatment approaches for anxiety disorders, finding that cognitive-behavioral therapy can be as effective as medication in many cases.
Is Internet Addiction Real? - Facts & StatsMaps of World
Find In-depth Review And Infographic About Internet Addiction. Learn more about Internet Addiction Disorder, stats by age group, symptoms, Internet Addiction survey, Facebook Addiction, Gaming Addiction, Gambling and Porn Addiction and Rehabilitation.
The document discusses the various effects that drug abuse and addiction can have on the human body and brain. It notes that drugs enter the body through injection, inhalation, or ingestion, which impacts how quickly they take effect. Some of the potential health effects of drug abuse include weakened immune systems, cardiovascular issues, liver damage, seizures, and permanent brain damage. Drug use can also lead to behavioral issues like paranoia, aggression, and impaired judgment. Pregnant women who use drugs risk having babies with birth defects, developmental and learning problems. Long term, drugs have been shown to alter brain chemistry and interfere with decision making, which can lead to compulsive drug craving and dependency.
This document discusses bone fractures, including general and specific classifications of fractures. It describes symptoms of fractures and methods for diagnosis using x-rays and other imaging techniques. The main treatments of fractures are discussed as external fixation using casts or internal fixation using surgical methods like plates, screws, nails or rods. Finally, the natural healing process of fractures is summarized in four steps.
This document discusses promoting health in older adults. It begins by defining aging and categorizing the aging population. It then outlines different care settings for elders, including acute care facilities, long-term care facilities, hospice, rehabilitation, and community settings. It also discusses common biologic theories of aging and physiological changes associated with aging, including changes to the integumentary, neurological, musculoskeletal, sensory, pulmonary, cardiovascular, gastrointestinal, urinary, immunological, and endocrine systems. Finally, it covers psychosocial theories of aging and developmental tasks of aging.
The document provides instructions for students to create and perform a drama piece based on the story of cyberbullying. It involves multiple steps: 1) Creating freeze frames showing scenarios of cyberbullying; 2) Devising and performing a scene showing the consequences of cyberbullying decisions; 3) Rehearsing and performing a scripted scene between a cyberbully and her victim; 4) Creating and performing a flashback scene showing why the cyberbullying began. The document provides assessment criteria for performance skills and directs students to plan and film their work to present the completed drama piece assessing their exploration of the impacts of cyberbullying.
8 million women and 2 million men in the US are diagnosed with osteoporosis. The document discusses the history of defining and diagnosing osteoporosis and osteopenia, and how drug companies worked to expand the definition of osteopenia to increase the market for osteoporosis drugs like Fosamax. Long term use of Fosamax has been linked to spontaneous bone fractures through impaired bone healing. Lifestyle factors like exercise, diet, and vitamin D can help promote strong bones.
The document discusses health promotion and the roles of pharmacists. It defines health promotion as enabling people to control and improve their health through skills and environmental changes. Pharmacists are well-positioned to conduct health promotion activities due to their accessibility and knowledge. The document outlines various health promotion strategies pharmacists can implement, such as providing educational materials, hosting displays, and taking opportunities during medicine sales to discuss health topics.
The parathyroid glands are four small glands located behind the thyroid gland, with one at each end of the upper and lower poles of the thyroid. The glands consist of two main cell types: chief cells and oxyphil cells. Chief cells are small polygonal cells that synthesize and secrete parathyroid hormone, which regulates blood calcium levels. Oxyphil cells are larger than chief cells and less numerous.
House dust mites are a major cause of asthma, allergic rhinitis, and atopic dermatitis. The two most common house dust mite species worldwide are Dermatophagoides pteronyssinus and Dermatophagoides farinae. House dust mites thrive in warm, humid environments and their allergens are found in dust in homes and can become airborne, easily being inhaled and triggering allergic reactions in sensitized individuals. Diagnosis of house dust mite allergy involves tests to detect house dust mite-specific IgE antibodies such as enzyme immunoassays. Preventive measures focus on reducing indoor humidity and house dust mite allergen levels through methods such as mattress
The document discusses the history and causes of allergies. It notes that allergy rates have tripled over the last 20 years. Potential causes discussed include the hygiene hypothesis (decreased exposure to bacteria), vaccinations, toxic food proteins from GMOs and preservatives, and genetics. Specific food additives and preservatives like sodium benzoate, sodium nitrate, and MSG are highlighted as potentially increasing health risks such as cancer and neurological diseases. The impacts of a lack of gut bacteria diversity from excessive antibiotic use and a lack of exposure to microorganisms are also discussed in relation to the hygiene hypothesis.
Cyberbullying involves intentionally and repeatedly harming others online through technologies like cell phones and social media. It can make victims feel sad, angry, or afraid. Common forms of cyberbullying include mean posts, messages, photos, or videos that are shared and spread widely. While some kids can handle cyberbullying, it has led some teens to depression and even suicide. Laws are being passed to help prevent cyberbullying and punish those who engage in it.
The document discusses wound classification and the normal process of wound healing. It defines wounds and classifies them into four categories (clean, clean-contaminated, contaminated, dirty/infected) based on the CDC's adaptation of the American College of Surgeons' wound classification schema. It then describes the four phases of normal acute wound healing: hemostasis, inflammation, proliferation, and remodeling. Hemostasis involves platelet aggregation and fibrin clot formation to stop bleeding. Inflammation brings neutrophils and macrophages to remove debris. Proliferation involves new tissue formation. Remodeling shapes the new tissue.
Health education aims to promote, maintain, and restore health. It involves educating individuals and groups on behaviors that improve health. Effective health education requires strong communication skills. Using audiovisual aids can make health education messages more clear, organized, and impactful as they allow concepts to be demonstrated and reinforced in a memorable way. Audiovisual aids also help match different learning styles and convey messages with less effort.
this is presentation talks about basic & updated advanced wounds care,,,,,,,2nd presentation in my internship..i hope you will get benefit from it ......Dr/ Wadie Madi
The document discusses cyber bullying and provides advice on preventing and responding to it. It defines cyber bullying as using technology like mobile phones or the internet to deliberately upset someone. It emphasizes the importance of having a shared understanding of cyber bullying across the school community and reviewing policies. Key steps to preventing cyber bullying include educating students on safe technology use, providing reporting methods, and using technology to promote self-esteem and relationships. Responding involves supporting the target, investigating, working with the bully, and potentially involving service providers or police.
The presentation is for the use of Physiotherapy students. It covers a brief introduction, classification, clinical features and general principles of management.
The document discusses various anxiety disorders and their treatment. It describes several anxiety disorders in detail, including generalized anxiety disorder, panic disorder, post-traumatic stress disorder, specific phobias, social anxiety disorder, and obsessive-compulsive disorder. It examines biological, psychological, and behavioral factors that may contribute to the development and maintenance of anxiety disorders. Finally, it reviews both biological and psychological treatment approaches for anxiety disorders, finding that cognitive-behavioral therapy can be as effective as medication in many cases.
Is Internet Addiction Real? - Facts & StatsMaps of World
Find In-depth Review And Infographic About Internet Addiction. Learn more about Internet Addiction Disorder, stats by age group, symptoms, Internet Addiction survey, Facebook Addiction, Gaming Addiction, Gambling and Porn Addiction and Rehabilitation.
The document discusses the various effects that drug abuse and addiction can have on the human body and brain. It notes that drugs enter the body through injection, inhalation, or ingestion, which impacts how quickly they take effect. Some of the potential health effects of drug abuse include weakened immune systems, cardiovascular issues, liver damage, seizures, and permanent brain damage. Drug use can also lead to behavioral issues like paranoia, aggression, and impaired judgment. Pregnant women who use drugs risk having babies with birth defects, developmental and learning problems. Long term, drugs have been shown to alter brain chemistry and interfere with decision making, which can lead to compulsive drug craving and dependency.
This document discusses bone fractures, including general and specific classifications of fractures. It describes symptoms of fractures and methods for diagnosis using x-rays and other imaging techniques. The main treatments of fractures are discussed as external fixation using casts or internal fixation using surgical methods like plates, screws, nails or rods. Finally, the natural healing process of fractures is summarized in four steps.
The document summarizes the structure and function of the nervous system in three main divisions:
1) The central nervous system (CNS) consists of the brain and spinal cord. The peripheral nervous system (PNS) consists of the nerve network outside the CNS.
2) Neuroglia are supportive cells in the nervous system that form myelin sheaths and blood-brain barriers. The most numerous neuroglial cell is the astrocyte.
3) Neurons handle communication in the nervous system and are classified as sensory, motor, or interneurons. Impulse conduction in neurons involves changes in membrane potential and the firing of action potentials.
This document provides information on the nervous system and common neurological diseases and disorders. It begins with an overview of the key structures of the nervous system, including neurons, dendrites, axons, and myelin sheath. It then describes the central nervous system, including the brain and spinal cord, and peripheral nervous system. Several common neurological conditions are then discussed in more detail, including stroke, transient ischemic attack, encephalitis, meningitis, brain abscess, poliomyelitis, Guillain-Barré syndrome, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, dementia, Huntington's disease, cerebral concussion/contusion, and spinal cord injury. For each condition, the
The document provides an overview of the digestive system and common digestive disorders. It describes the anatomy and functions of the digestive tract organs, the processes of digestion and absorption, and neural and hormonal controls. Common manifestations of digestive disorders discussed include anorexia, nausea, vomiting, diarrhea, blood in stool, gas, and constipation. Dehydration and electrolyte imbalances are noted as potential complications.
The document discusses endocrine system disorders and diabetes mellitus. It covers the location and functions of endocrine glands, classification of hormones, control of the endocrine system through feedback loops, sources and effects of major hormones, and disorders that can result from excess or deficits of hormones. Specific attention is given to diabetes mellitus, including the different types, manifestations, diagnostic tests, treatment principles, and acute and chronic complications if blood glucose levels are not well-controlled.
The document summarizes the anatomy and physiology of the eye and visual system. It describes the main parts of the eye including the cornea, iris, lens, retina, and optic nerve. It explains how light enters the eye and is focused on the retina to initiate visual signals through the optic nerve. The document also discusses common eye disorders like myopia, hyperopia, glaucoma, and conjunctivitis as well as infections, injuries, and defects that can affect vision.
This document provides an overview of the nervous system, including its main components and functions. It describes the central nervous system including the brain and spinal cord, as well as the peripheral nervous system. It then discusses the various parts of the brain in detail, including protective structures like the meninges and cerebrospinal fluid. It also outlines the cranial nerves, spinal cord, spinal nerves, reflexes, and basic neuron structure and function.
The document discusses the respiratory system, including its purpose of transporting oxygen and removing carbon dioxide. It describes the anatomy of the upper and lower respiratory tract. Key points include that the upper tract has resident flora while the lower tract is sterile. It also discusses ventilation, gas exchange, control of breathing, diagnostic tests for respiratory disorders, and general manifestations of respiratory disease such as coughing, sputum, and breathing patterns.
This document provides an overview of blood and circulatory system disorders. It begins with a review of the circulatory system and its components. It then discusses blood vessels including arteries, veins, and capillaries. Next, it covers the components and functions of blood, including plasma, red blood cells, white blood cells, and platelets. The document proceeds to describe various blood disorders such as anemias, hemolytic anemia, sickle cell anemia, and aplastic anemia. It provides details on diagnostic tests and blood therapies for treating various blood-related conditions.
The document is a chapter from a medical terminology textbook about male reproductive medicine. It includes learning objectives about the male genitourinary system, as well as sections on anatomy and physiology, spermatogenesis, sexual maturity, and ejaculation. Figures and diagrams are provided to illustrate the structures of the male reproductive system.
The document discusses urology and the urinary system. It covers the anatomy and physiology of the urinary system, including the structures of the kidneys, ureters, bladder, and urethra. It describes the process of urine production in the nephrons of the kidneys and the transportation of urine through the urinary system to be excreted from the body. It also lists learning objectives about the urinary system, diseases, diagnostic tests, and medical terminology.
This document provides an overview of chapter 10 from the third edition of the textbook Medical Language by Susan M. Turley. The chapter covers neurology and includes learning objectives, multimedia resources, and detailed descriptions of the anatomy and physiology of the central nervous system including the brain, cerebrum, lobes, ventricles, brainstem, cerebellum, and spinal cord.
The document discusses the muscular system and orthopedics. It covers the anatomy and physiology of muscles, including the three types of muscles (skeletal, cardiac, smooth), origins and insertions, and related structures like tendons. It describes the specialty of orthopedics and different types of muscle movement like flexion, extension, abduction, and rotation. It includes diagrams of muscle anatomy and movements. It also provides learning objectives and multimedia resources for further study.
This document provides an overview of the musculoskeletal system, including bones, muscles, joints, and common disorders. It begins by describing bone tissue and classifying bone shapes. It then discusses skeletal muscle structure and function. Various joint types and structures are outlined. Common musculoskeletal disorders like fractures, dislocations, muscle tears, and bone diseases such as osteoporosis are then summarized. Diagnostic tests and treatment approaches for musculoskeletal conditions are also briefly reviewed.
The document discusses various skin disorders and lesions. It begins by reviewing the normal anatomy and layers of the skin, including the epidermis, dermis, and hypodermis. It then describes common inflammatory disorders like contact dermatitis, urticaria, atopic dermatitis, and psoriasis. The document also covers various skin infections caused by bacteria, viruses, and other microbes like impetigo, cellulitis, herpes simplex, and leprosy. Diagnostic tests and general treatment measures for skin conditions are also mentioned.
This document provides an overview of the chapter on dermatology from the third edition of the textbook Medical Language. It begins with learning objectives for the chapter, which cover topics like the anatomy of the integumentary system, allergic reactions, common dermatological diseases and procedures, and medical terminology related to the skin. The bulk of the document then describes in detail the anatomy and physiology of the integumentary system, including the layers of the skin, hair follicles, sebaceous and sweat glands, and nails. It also discusses the process of allergic reactions and lists some general dermatological diseases. Diagrams and links to multimedia are provided throughout for additional reference.
This document discusses neoplasms and cancer. It begins by defining key terms like differentiation, mitosis, mutation, and apoptosis. It then describes the characteristics of benign and malignant tumors, noting that malignant tumors lack control of cell growth and can spread to other sites. The document outlines various diagnostic tests for cancer and explains how cancer spreads through invasion and metastasis. It discusses factors that can increase cancer risk and lists some treatment options like surgery, chemotherapy, and radiation therapy.
The document summarizes key aspects of the immune system. It describes the components of the immune system including lymphoid structures, immune cells, and tissues responsible for immune cell development. It also discusses the nonspecific and specific immune responses, antibodies, immunity types, hypersensitivity reactions, and immunodeficiencies.
This document summarizes key concepts about ratios, proportions, and percents from Chapter 3 of a textbook on math and dosage calculations for healthcare professionals. It defines important terms like ratio, proportion, and percent. It provides rules and examples for converting between ratios, proportions, percents, fractions and decimals. It also explains how to use proportions to solve for unknown quantities, including setting up equations and checking solutions. The overall purpose is to explain essential skills for understanding relationships between quantities and solving dosage calculation problems.
The document discusses inflammation and healing. It describes the three lines of defense in the body against pathogens: mechanical barriers, inflammation, and specific immune responses. Inflammation is defined as a protective response to infection or injury and involves redness, swelling, heat, pain, and loss of function. The stages of acute inflammation and factors that influence the inflammatory response like chemical mediators are examined. Treatment options for inflammation including medications are also reviewed.
This document describes the cardiovascular system and its anatomy. It discusses the structures of the heart including the chambers, valves, layers and muscles. It describes the major blood vessels including arteries, capillaries and veins. It explains the dual circulation of blood through the systemic and pulmonary circuits. Learning objectives cover identifying cardiovascular structures, describing diseases and procedures, and building medical terminology related to cardiology.
The endocrine system consists of the glands shown here as well as clusters of hormone-secreting cells in various organs, including the brain, heart, and small intestine.
The glands secrete chemicals (called hormones) that influence almost every cell and organ in the body.
Endocrine glands are ductless glands: they secrete their hormones directly into the bloodstream.
The cells of many different organs are exposed to a particular hormone; however, only cells having receptors for that hormone (called target cells) will respond.
The actions of the endocrine and nervous systems complement one another to ensure that the body maintains homeostasis.
Hormones can be classified as steroid or nonsteroid: steroid hormones are synthesized from cholesterol; nonsteroid (protein-based) hormones are synthesized from amino acids.
Once a hormone reaches target cell, it binds with a receptor to trigger changes within the cell.
Steroid hormones pass easily through a cell’s membrane; once inside the cell, they bind to receptors in the nucleus.
Protein-based hormones can’t penetrate the cell wall; they bind to receptors on the cell surface. The binding activates a second messenger system: a cascade of processes that results in the production of a second messenger. The second messenger activates specific enzymes. The enzymes influence cellular reactions, producing the cell’s response to the hormone.
The pituitary gland influences more body processes than any other endocrine gland.
The pea-sized pituitary gland sits underneath the hypothalamus. It lies in the sella turcica, a cavity within the sphenoid bone.
A stalk called the infundibulum connects the hypothalamus and pituitary.
The pituitary gland is two distinct glands: the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary).
The anterior pituitary is the larger of the two pituitary glands. It consists of glandular tissue and secretes a number of important hormones under the direction of the hypothalamus.
Neurons within the hypothalamus synthesize releasing hormones (which stimulate the anterior pituitary to secrete its hormones) as well as inhibiting hormones (which suppress hormone secretion by the anterior pituitary).
Neurons of the hypothalamus release their hormones into a system of blood vessels called the hypophyseal portal system. The blood travels straight to the anterior pituitary, where the hormones from the hypothalamus act on target cells in the anterior pituitary, causing them to release certain hormones into the general circulation.
Each hormone acts on the anterior pituitary to release, or suppress, a particular hormone. (For example, thyrotropin-releasing hormone stimulates the anterior pituitary to release thyrotropin [also called thyroid-stimulating hormone]; in turn, this hormone stimulates the thyroid to secrete thyroid hormone [TH].)
Thyroid-stimulating hormone stimulates the thyroid gland to secrete thyroid hormone.
Prolactin stimulates milk production in the mammary glands in females. In males, it may make the testes more sensitive to luteinizing hormone.
Adrenocorticotropic hormone stimulates the adrenal cortex to secrete corticosteroids.
Follicle-stimulating hormone, a gonadotropin, stimulates the production of eggs in the ovaries of females and sperm in the testes of males.
Luteinizing hormone, a gonadotropin, stimulates ovulation and estrogen and progesterone synthesis in females and the secretion of testosterone by the testes in males.
Growth hormone, or somatotropin, acts on the entire body to promote protein synthesis, lipid and carbohydrate metabolism, and bone and skeletal muscle growth.
The posterior pituitary is made of neural tissue (in contrast with the anterior pituitary, which is made of glandular tissue). Instead of synthesizing hormones, the posterior pituitary stores the hormones antidiuretic hormone (ADH) and oxytocin (OT), which are synthesized by the hypothalamus.
Oxytocin stimulates contraction of the uterus during childbirth and triggers the release of milk from the breasts during lactation.
ADH (or vasopressin) acts on the kidneys to reduce urine volume and prevent dehydration.
Nerve fibers that form the posterior pituitary originate in the hypothalamus.
The hypothalamic neurons synthesize hormones, which they send down to the posterior pituitary to be stored until stimulated by the nervous system to release them.
Secretion of pituitary hormones occurs in phases or pulses.
Hormone secretion is controlled by the central nervous system and by the target organs through negative feedback.
Example: Cold stimulates hypothalamus to release thyrotropin-releasing hormone (TRH). TRH stimulates anterior pituitary to release TSH. TSH stimulates thyroid to release thyroid hormones. Thyroid hormones stimulate metabolism to increase warmth and inhibit the release of TSH by the pituitary.
The pineal gland is located on the roof of the brain’s third ventricle.
The pineal gland produces melatonin, a hormone that rises at night (when sunlight is absent) and falls during the day. High melatonin levels trigger sleepiness, making it a key factor in the sleep/wake cycle.
The pineal gland may also regulate the timing of puberty.
The thymus lies in the mediastinum just beneath the sternum.
In children, the thymus gland is large. It begins to shrink in puberty; by old age, it consists of mostly fat and fibrous tissue.
The thymus secretes thymosin and thymopoietin, which have a role in the development of the immune system. Because it secretes hormones, the thymus is a member of the endocrine system; the actions of the hormones make the thymus part of the immune system.
The thyroid is the largest endocrine gland; it consists of two large lobes connected by a narrow band of tissue called the isthmus.
The thyroid gland resides in the neck; it wraps around the anterior and lateral portions of the trachea.
Thyroid tissue is made of tiny sacs called thyroid follicles. Each follicle is filled with a thick fluid called thyroid colloid. The cells lining the sacs secrete the two main thyroid hormones: T3 (triiodothyronine) and T4 (thyroxine). (Unlike other glands, the thyroid gland can store the hormones for later use.)
Cells between the thyroid follicles (parafollicular cells) secrete the hormone calcitonin in response to increasing blood calcium levels; calcitonin triggers the deposition of calcium in bone and, thus, promotes bone formation.
Parathyroid glands lie on the posterior surface of the thyroid; they secrete parathyroid hormone (PTH) in response to low blood levels of calcium.
Most people have four parathyroid glands, but the number of glands, and their locations, can vary.
PTH is the main hormone used to maintain normal blood levels of calcium. (Normal nerve and muscle function, blood clotting, cell membrane permeability, and the function of certain enzymes all depend on adequate levels of calcium.)
PTH inhibits new bone formation and stimulates the breakdown of old bone, causing calcium (and phosphate) to move out of bone and into the blood. PTH encourages the kidneys to reabsorb calcium. PTH also prompts the kidneys to activate vitamin D, which is important for intestinal absorption of calcium.
Calcitonin (secreted by the thyroid) has antagonistic effects on parathyroid hormone (PTH). The interaction of these two hormones helps the body achieve calcium homeostasis.
Each adrenal gland is two distinct glands. The inner portion (adrenal medulla) consists of modified neurons and functions as part of the sympathetic nervous system. The outer portion (adrenal cortex) is glandular tissue and secretes steroid hormones (corticosteroids).
The adrenal medulla contains modified neurons (chromaffin cells) that act as part of the sympathetic nervous system. These cells secrete the catecholamines epinephrine and norepinephrine in response to stimulation.
Catecholamines prepare the body for physical activity by increasing heart rate and blood pressure, stimulating circulation to the muscles, and dilating the bronchioles; they also boost glucose levels (a source of fuel) by breaking down glycogen into glucose (glycogenolysis) and converting fatty acids and amino acids into glucose (gluconeogenesis).
The adrenal cortex consists of three layers of glandular tissue:
Zona glomerulosa (the outermost layer) secretes mineralocorticoids.
Zona fasciculata (the middle layer) secretes glucocorticoids.
Zona reticularis (the innermost layer) secretes sex steroids.
Aldosterone acts on the kidneys to promote Na+ retention and K+ excretion; in turn, it also causes water retention.
Cortisol (the principal glucocorticoid) helps the body adapt to stress and repair damaged tissues by stimulating the breakdown of fat and protein, converting fat and protein to glucose, and the release of fatty acids and glucose into the blood. Cortisol has an anti-inflammatory effect, suppresses the immune system if secreted over a long term, and is essential for maintaining a normal blood pressure.
Sex steroids include a weak form of androgen (that is converted to the more potent androgen testosterone) and small amounts of estrogen.
The pancreas contains both endocrine and exocrine tissues: the majority of the pancreas acts as an exocrine gland, but a small percentage serves an important endocrine function.
Exocrine cells (acini) secrete digestive enzymes into ducts that drain into the small intestine.
Interspersed with the exocrine cells are clusters of endocrine cells called pancreatic islets or the islets of Langerhans. The pancreatic islets contain alpha cells, beta cells, and delta cells.
Alpha cells secrete the hormone glucagon between meals, when blood glucose levels decline. Glucagon stimulates liver cells to convert glycogen into glucose and to convert fatty acids and amino acids into glucose (gluconeogenesis). The resulting glucose is released into the bloodstream, causing blood glucose levels to increase.
Beta cells secrete the hormone insulin. After eating, the levels of glucose and amino acids in the blood increase. Insulin stimulates cells to absorb these nutrients, causing blood glucose levels to decline.
Delta cells secrete somatostatin, a hormone that works within the pancreas to regulate the other endocrine cells. (It inhibits the release of glucagon, insulin, and growth hormone.)
Sex hormones stimulate the production of eggs (in females) and sperm (in males).
Estrogen helps promote the development of female characteristics (such as breast development) and contributes to the development of the reproductive system.
After ovulation, the corpus luteum (the tissue left behind after a rupture of a follicle during ovulation) secretes progesterone. Progesterone, in combination with estrogen, helps maintain the uterine lining during pregnancy.
Testosterone triggers the development of male sexual characteristics; it also sustains sperm production.