The Endocrine System By: Karl, Manny, Alondra, and Joseph.

The Endocrine SystemThe Endocrine SystemBy: Karl, Manny, Alondra, and JosephBy: Karl, Manny, Alondra, and Joseph

The Endocrine SystemThe Endocrine System

The endocrine system includes all of the glands of the body The endocrine system includes all of the glands of the body and the hormones produced by those glands. The glands and the hormones produced by those glands. The glands are controlled directly by stimulation from the nervous are controlled directly by stimulation from the nervous system as well as by chemical receptors in the blood and system as well as by chemical receptors in the blood and hormones produced by other glands. By regulating the hormones produced by other glands. By regulating the functions of organs in the body, these glands help to functions of organs in the body, these glands help to maintain the body’s homeostasis. Cellular metabolism, maintain the body’s homeostasis. Cellular metabolism, reproduction, sexual development, sugar and mineral reproduction, sexual development, sugar and mineral homeostasis, heart rate, and digestion are among the homeostasis, heart rate, and digestion are among the many processes regulated by the actions of hormones.many processes regulated by the actions of hormones.

Hypothalamus and Hypothalamus and Pituitary GlandPituitary Gland

The hypothalamus regulates the internal environment.The hypothalamus regulates the internal environment.Example: through the autonomic system it helps control heartbeat, body Example: through the autonomic system it helps control heartbeat, body

temperature, and water balance.temperature, and water balance.Control the glandular secretions of the pituitary gland (hypophysis). Control the glandular secretions of the pituitary gland (hypophysis). A small pituitary glad is about 1cm in diameter and is connected to the A small pituitary glad is about 1cm in diameter and is connected to the

hypothalamus by a stalk like structure. hypothalamus by a stalk like structure. The pituitary consist of the: The pituitary consist of the: posterior pituitary portionposterior pituitary portion

(neurohypophysis) and the (neurohypophysis) and the anterior pituitary portion anterior pituitary portion (adrenohypophysis) (adrenohypophysis)

Posterior PituitaryPosterior Pituitary

NeurosecretoryNeurosecretory cells (neurons in hypothalamus) produce the cells (neurons in hypothalamus) produce the antidiuretic hormoneantidiuretic hormone (ADH) and (ADH) and oxytocin.oxytocin.

These hormones pass through the axons into the posterior pituitary These hormones pass through the axons into the posterior pituitary where they are stored in axon endings. where they are stored in axon endings.

The The hypothalamic hormonehypothalamic hormone, , antidiuretic hormoneantidiuretic hormone, and , and oxytocinoxytocin are produced in the hypothalamus but are released into the are produced in the hypothalamus but are released into the bloodstream from the posterior pituitary. bloodstream from the posterior pituitary.

Antidiuretic hormone Antidiuretic hormone and Oxytocinand Oxytocin

ADH ADH (antidiuretic hormone also known called vasopressin) also (antidiuretic hormone also known called vasopressin) also called vasopressin is released from the posterior pituitarycalled vasopressin is released from the posterior pituitary

Upon reaching the kidneys, ADH causes more water to be Upon reaching the kidneys, ADH causes more water to be reabsorbed into kidney capillaries.reabsorbed into kidney capillaries.

as the blood become dilute once again ADH is no longer released as the blood become dilute once again ADH is no longer released an additional effect of ADH is to raise blood pressure by an additional effect of ADH is to raise blood pressure by

vasoconstruction of blood vessels through out the bodyvasoconstruction of blood vessels through out the bodyinability to produce ADH causes inability to produce ADH causes diadetes insipidusdiadetes insipidus (watery (watery

urine) in which a person produces copious amounts of urine with a urine) in which a person produces copious amounts of urine with a resultant loss of ions from the bloodresultant loss of ions from the blood

oxytocinoxytocin which is the other hormone made in the hypothalamus which is the other hormone made in the hypothalamus cause uterine contraction during childbirth and milk letdown when a cause uterine contraction during childbirth and milk letdown when a baby is nursing baby is nursing

Anterior PituitaryAnterior Pituitary

TThe portal system of two capillary networks or beds connected by a he portal system of two capillary networks or beds connected by a vein lies between the hypothalamus and the anterior pituitaryvein lies between the hypothalamus and the anterior pituitary

TThe hypothalamus controls the anterior pituitary by providinghe hypothalamus controls the anterior pituitary by providing hypothalamic-releasing hormones hypothalamic-releasing hormones and and hypothalamic-hypothalamic-inhibiting hormones inhibiting hormones

Hormones that affect Hormones that affect other glandsother glands

Three hormones produced by the anterior pituitary have an effect on Three hormones produced by the anterior pituitary have an effect on other glands other glands

Thyroid-stimulating hormone (TSH) Thyroid-stimulating hormone (TSH) stimulates the thyroid to stimulates the thyroid to produce the thyroid horomones produce the thyroid horomones

Adrenocorticotropic hormone (ACTH) Adrenocorticotropic hormone (ACTH) stimulates the adrenal stimulates the adrenal cortex to produce its hormonescortex to produce its hormones

Gonadotropic Hormones Gonadotropic Hormones stimulates the gonads, the testes in stimulates the gonads, the testes in the males, and the ovaries in females to produce gametes and sex the males, and the ovaries in females to produce gametes and sex hormoneshormones

The hypothalamus the anterior pituitary and other glands controlled The hypothalamus the anterior pituitary and other glands controlled by anterior pituitary are all involved in self-regulating negative by anterior pituitary are all involved in self-regulating negative feedback mechnism that maintain stable condition feedback mechnism that maintain stable condition

Effects of other Effects of other hormoneshormones

Other hormones produced by the anterior Pituitary do not affect Other hormones produced by the anterior Pituitary do not affect other endocrine glands other endocrine glands

Prolactin (PRL) Prolactin (PRL) is produced at the beginning of the 5is produced at the beginning of the 5thth month of a month of a pregnancy pregnancy

It causes the mammary glands in the breast to develop milkIt causes the mammary glands in the breast to develop milkGrowth Hormones (GH) – Growth Hormones (GH) – somatotropic hormone stimulates somatotropic hormone stimulates

protein synthesis with in cartilage bone and muscleprotein synthesis with in cartilage bone and muscle

Effects of growth Effects of growth hormoneshormones

If to little GH is produced during childhood they have pituitary If to little GH is produced during childhood they have pituitary dwarfism which are characterized by perfect proportions but small dwarfism which are characterized by perfect proportions but small staturestature

If to much GH is secreted then the person ca become a giant, which If to much GH is secreted then the person ca become a giant, which usually have poor health become secondary effect on blood sugar usually have poor health become secondary effect on blood sugar levellevel

Thyroid and parathyroid Thyroid and parathyroid glandsglands

Thyroid Gland is a large gland located in the where it is attached Thyroid Gland is a large gland located in the where it is attached trachea just below the larynx trachea just below the larynx

Is Composed f a large number of follicles each a small spherical Is Composed f a large number of follicles each a small spherical structure made of thyroid cells filed with triiodothyronine which structure made of thyroid cells filed with triiodothyronine which contains three iodine atomcontains three iodine atom

Thyroxine which four iodine atoms Thyroxine which four iodine atoms

Effects of thyroid Effects of thyroid hormoneshormones

The thyroid gland actively acquires iodine to produce triiodothyronine and The thyroid gland actively acquires iodine to produce triiodothyronine and thyroxine.thyroxine.

If iodine is lacking in a diet the Thyroid glands are unable to produce thyroid If iodine is lacking in a diet the Thyroid glands are unable to produce thyroid hormoneshormones

Constant stimulation by the anterior pituitary results in the thyroid enlarging, Constant stimulation by the anterior pituitary results in the thyroid enlarging, resulting in a simple, or endemic, goiter.resulting in a simple, or endemic, goiter.

Thyroid hormones do not have single target organs; instead they stimulate all cells Thyroid hormones do not have single target organs; instead they stimulate all cells of the body to metabolize at a faster rate of the body to metabolize at a faster rate

Congenital hypothyroidismCongenital hypothyroidism: undesecretion of thyroid hormone : undesecretion of thyroid hormone Hypothyroidism stocky and short in extreme cases since infancy or childhood.Hypothyroidism stocky and short in extreme cases since infancy or childhood.For adults with this condition its called mixedema, which is characterized by For adults with this condition its called mixedema, which is characterized by

lethargy, weight gain, loss of hair, slower pulse rate, lowered body temperature, and lethargy, weight gain, loss of hair, slower pulse rate, lowered body temperature, and thickness and puffiness of the skin.thickness and puffiness of the skin.

Hyperthyroidism: Hyperthyroidism: oversecretion of thyroid hormone oversecretion of thyroid hormone The thyroid gland is overactive and a exophthalimic goiter forms.The thyroid gland is overactive and a exophthalimic goiter forms.Hyperthyroidism can also be caused by a thyroid tumor which is determined as a Hyperthyroidism can also be caused by a thyroid tumor which is determined as a

lump.lump.Treatment is surgery with administration of radioactive iodine.Treatment is surgery with administration of radioactive iodine.

CalcitoninCalcitonin

Calcitonin:Calcitonin: a hormone secreted by the thyroid gland when the a hormone secreted by the thyroid gland when the blood calcium level rises blood calcium level rises

Primary effect is to bring the deposit of calcium in the bones Primary effect is to bring the deposit of calcium in the bones (osteoclasts)(osteoclasts)

Low calcium level stimulates the release of parathyroid hormones Low calcium level stimulates the release of parathyroid hormones by the parathyroid glands by the parathyroid glands

Calcitonin can be used therapeutically in adults to reduce the effects Calcitonin can be used therapeutically in adults to reduce the effects of osteoporosis.of osteoporosis.

Parathyroid glandsParathyroid glands

Parathyroid Glands: Parathyroid Glands: causes the blood phosphate level to derease causes the blood phosphate level to derease and the ionic blood calcium level to increaseand the ionic blood calcium level to increase

The antagonistic actions of calcitonin from the thyroid gland and The antagonistic actions of calcitonin from the thyroid gland and parathyroid glands maintain the blood calcium level within normal parathyroid glands maintain the blood calcium level within normal limits limits

When insufficient parathyroid hormone production leads to a When insufficient parathyroid hormone production leads to a dramatic drop in blood calcium level, hypocalcmic tenani makes the dramatic drop in blood calcium level, hypocalcmic tenani makes the body shake from continuous muscle contraction.body shake from continuous muscle contraction.

The effect is brought by increased excitability of the nerves, which The effect is brought by increased excitability of the nerves, which initiates nerve impulses spontaneously and without rest (severe cases initiates nerve impulses spontaneously and without rest (severe cases can be fatal)can be fatal)

Adrenal GlandsAdrenal Glands

The The adrenal glands are a pair of roughly triangular glands found immediately are a pair of roughly triangular glands found immediately superior to the kidneys. The adrenal glands are each made of 2 distinct layers, each superior to the kidneys. The adrenal glands are each made of 2 distinct layers, each with their own unique functions: the outer adrenal cortex and inner adrenal medulla.with their own unique functions: the outer adrenal cortex and inner adrenal medulla.

•• Adrenal cortexAdrenal cortex: The adrenal cortex produces many cortical hormones in 3 : The adrenal cortex produces many cortical hormones in 3 classes: glucocorticoids, mineralocorticoids, and androgens. classes: glucocorticoids, mineralocorticoids, and androgens.

1.1. Glucocorticoids have many diverse functions, including the breakdown of Glucocorticoids have many diverse functions, including the breakdown of proteins and lipids to produce glucose. Glucocorticoids also function to reduce proteins and lipids to produce glucose. Glucocorticoids also function to reduce inflammation and immune response.inflammation and immune response.

2.2. Mineralocorticoids, as their name suggests, are a group of hormones that help Mineralocorticoids, as their name suggests, are a group of hormones that help to regulate the concentration of mineral ions in the body.to regulate the concentration of mineral ions in the body.

3.3. Androgens, such as testosterone, are produced at low levels in the adrenal Androgens, such as testosterone, are produced at low levels in the adrenal cortex to regulate the growth and activity of cells that are receptive to male cortex to regulate the growth and activity of cells that are receptive to male hormones. In adult males, the amount of androgens produced by the testes is many hormones. In adult males, the amount of androgens produced by the testes is many times greater than the amount produced by the adrenal cortex, leading to the times greater than the amount produced by the adrenal cortex, leading to the appearance of male secondary sex characteristics.appearance of male secondary sex characteristics.

Adrenal MedullaAdrenal Medulla

The adrenal medulla produces the hormones epinephrine The adrenal medulla produces the hormones epinephrine and norepinephrine under stimulation by the sympathetic and norepinephrine under stimulation by the sympathetic division of the autonomic nervous system. Both of these division of the autonomic nervous system. Both of these hormones help to increase the flow of blood to the brain hormones help to increase the flow of blood to the brain and muscles to improve the “fight-or-flight” response to and muscles to improve the “fight-or-flight” response to stress. These hormones also work to increase heart rate, stress. These hormones also work to increase heart rate, breathing rate, and blood pressure while decreasing the breathing rate, and blood pressure while decreasing the flow of blood to and function of organs that are not involved flow of blood to and function of organs that are not involved in responding to emergencies.in responding to emergencies.

PancreasPancreas

The The pancreas is a large gland located in the abdominal cavity just is a large gland located in the abdominal cavity just inferior and posterior to the inferior and posterior to the stomach. The pancreas is considered to . The pancreas is considered to be a heterocrine gland as it contains both endocrine and exocrine be a heterocrine gland as it contains both endocrine and exocrine tissue. The endocrine cells of the pancreas make up just about 1% of tissue. The endocrine cells of the pancreas make up just about 1% of the total mass of the pancreas and are found in small groups the total mass of the pancreas and are found in small groups throughout the pancreas called islets of Langerhans. Within these throughout the pancreas called islets of Langerhans. Within these islets are 2 types of cells—alpha and beta cells. The alpha cells islets are 2 types of cells—alpha and beta cells. The alpha cells produce the hormone glucagon, which is responsible for raising produce the hormone glucagon, which is responsible for raising blood glucose levels. Glucagon triggers muscle and liver cells to blood glucose levels. Glucagon triggers muscle and liver cells to break down the polysaccharide glycogen to release glucose into the break down the polysaccharide glycogen to release glucose into the bloodstream. The beta cells produce the hormone insulin, which is bloodstream. The beta cells produce the hormone insulin, which is responsible for lowering blood glucose levels after a meal. Insulin responsible for lowering blood glucose levels after a meal. Insulin triggers the absorption of glucose from the blood into cells, where it triggers the absorption of glucose from the blood into cells, where it is added to glycogen molecules for storage.is added to glycogen molecules for storage.

Adipose Tissue Adipose Tissue

Adipose tissue produces the hormone leptin that is involved in Adipose tissue produces the hormone leptin that is involved in the management of appetite and energy usage by the body. the management of appetite and energy usage by the body. Leptin is produced at levels relative to the amount of adipose Leptin is produced at levels relative to the amount of adipose tissue in the body, allowing the brain to monitor the body’s tissue in the body, allowing the brain to monitor the body’s energy storage condition. When the body contains a sufficient energy storage condition. When the body contains a sufficient level of adipose for energy storage, the level of leptin in the level of adipose for energy storage, the level of leptin in the blood tells the brain that the body is not starving and may work blood tells the brain that the body is not starving and may work normally. If the level of adipose or leptin decreases below a normally. If the level of adipose or leptin decreases below a certain threshold, the body enters starvation mode and certain threshold, the body enters starvation mode and attempts to conserve energy through increased hunger and attempts to conserve energy through increased hunger and food intake and decreased energy usage. Adipose tissue also food intake and decreased energy usage. Adipose tissue also produces very low levels of estrogens in both men and women. produces very low levels of estrogens in both men and women. In obese people the large volume of adipose tissue may lead to In obese people the large volume of adipose tissue may lead to abnormal estrogen levels.abnormal estrogen levels.

Other thyroid glandsOther thyroid glands

The body has many other endocrine glands, such as the testes The body has many other endocrine glands, such as the testes in males and ovaries in females. The thymus and pineal in males and ovaries in females. The thymus and pineal glands produce hormones. Some tissues within organs glands produce hormones. Some tissues within organs produce hormones and/ or growth factors. Individual body produce hormones and/ or growth factors. Individual body cells produce local messenger chemicals called prostaglandin.cells produce local messenger chemicals called prostaglandin.

Testes and OvariesTestes and Ovaries

The testes are located in the scrotum, and the ovaries are The testes are located in the scrotum, and the ovaries are located in the pelvic cavity. The testes produce androgens (i.e. located in the pelvic cavity. The testes produce androgens (i.e. testosterone), which are the male sex hormones. The ovaries testosterone), which are the male sex hormones. The ovaries produce estrogens and progesterone, the female sex produce estrogens and progesterone, the female sex hormones. The hypothalamus and pituitary gland control the hormones. The hypothalamus and pituitary gland control the hormonal secretions of these organs. (See page 208)hormonal secretions of these organs. (See page 208)

Cont.Cont.AndrogensAndrogens

Puberty is the moment in life when sexual maturation occurs. The greatly increased Puberty is the moment in life when sexual maturation occurs. The greatly increased testosterone secretion during this time stimulates the growth of the penis and the testes. testosterone secretion during this time stimulates the growth of the penis and the testes. Testosterone also brings about and maintains the male secondary sex characteristics that Testosterone also brings about and maintains the male secondary sex characteristics that develop during puberty, including the growth of a beard, axillary hair, and pubic hair. It develop during puberty, including the growth of a beard, axillary hair, and pubic hair. It prompts the larynx and vocal cords to enlarge, causing the voice to change. It’s partially prompts the larynx and vocal cords to enlarge, causing the voice to change. It’s partially responsible for the muscular strength of males. This is why some athletes take large responsible for the muscular strength of males. This is why some athletes take large amounts of anabolic steroids. (See page 220). Testosterone also stimulates oil and sweat amounts of anabolic steroids. (See page 220). Testosterone also stimulates oil and sweat glands in the skin; therefore it’s largely responsible for acne and body odor. Another side glands in the skin; therefore it’s largely responsible for acne and body odor. Another side effect of testosterone is baldness. Genes for baldness are probably inherited by both effect of testosterone is baldness. Genes for baldness are probably inherited by both sexes, but baldness is seen more in males due to the presence of testosterone. sexes, but baldness is seen more in males due to the presence of testosterone.

Estrogen and ProgesteroneEstrogen and Progesterone

The female sex hormones have many effects on the body. In particular, estrogens The female sex hormones have many effects on the body. In particular, estrogens secreted during puberty stimulate the growth of the uterus and the vagina. Estrogen is secreted during puberty stimulate the growth of the uterus and the vagina. Estrogen is necessary for ovum maturation and it’s largely responsible for the secondary sex necessary for ovum maturation and it’s largely responsible for the secondary sex characteristics in females, including female body hair and fat distribution. The pelvic characteristics in females, including female body hair and fat distribution. The pelvic girdle is wider in females than it is in males, resulting in a larger pelvic cavity. Both girdle is wider in females than it is in males, resulting in a larger pelvic cavity. Both estrogen and progesterone are needed for breast development and for regulation of the estrogen and progesterone are needed for breast development and for regulation of the uterine cycle, which includes monthly uterine cycle, which includes monthly

Thymus GlandThymus Gland

The lobular thymus gland, which lies just beneath the The lobular thymus gland, which lies just beneath the sternum, reaches its largest size and is most active during sternum, reaches its largest size and is most active during childhood. (See figure 10.1). When lymphocytes pass childhood. (See figure 10.1). When lymphocytes pass complete development in the thymus, they’re transformed complete development in the thymus, they’re transformed into thymus-derived lymphocytes, or T-lymphocytes. The into thymus-derived lymphocytes, or T-lymphocytes. The lobules of the thymus gland are lined by epithelial cells that lobules of the thymus gland are lined by epithelial cells that secrete hormones called thymosins. This hormone aids in secrete hormones called thymosins. This hormone aids in the differentiation of lymphocytes packed inside the the differentiation of lymphocytes packed inside the lobules. lobules.

Pineal glandPineal gland

The pineal gland, which is located in the brain, produces the hormone The pineal gland, which is located in the brain, produces the hormone melatonin, primarily at night. (See figure 10.1). Melatonin is involved in melatonin, primarily at night. (See figure 10.1). Melatonin is involved in our daily sleep-wake cycle; normally we grow sleepy at night when our daily sleep-wake cycle; normally we grow sleepy at night when melatonin levels increase and awake once daylight returns and melatonin melatonin levels increase and awake once daylight returns and melatonin levels decrease. (See figure 10.15). Daily 24-hour cycles such are this are levels decrease. (See figure 10.15). Daily 24-hour cycles such are this are called circadian rhythms. Circadian rhythms are controlled by an internal called circadian rhythms. Circadian rhythms are controlled by an internal timing mechanism called a biological clock. Based on animal research, it timing mechanism called a biological clock. Based on animal research, it appears that melatonin also regulates sexual development. It’s also been appears that melatonin also regulates sexual development. It’s also been noted that children whose pineal gland has been destroyed due to a brain noted that children whose pineal gland has been destroyed due to a brain tumor experience early puberty.tumor experience early puberty.

Hormones from Other TissuesHormones from Other Tissues

We previously mentioned that the heart produces atrial natriuretic We previously mentioned that the heart produces atrial natriuretic hormone (see page 214). The kidney also influences the cardiovascular hormone (see page 214). The kidney also influences the cardiovascular system function by producing the hormone erythropoietin (EPO), which system function by producing the hormone erythropoietin (EPO), which stimulates red blood cell reproduction by the bone marrow. stimulates red blood cell reproduction by the bone marrow.

LeptinLeptin

Leptin is a protein hormone produced by adipose tissue. Leptin is a protein hormone produced by adipose tissue. Leptin acts on the hypothalamus, where its signals satiety- Leptin acts on the hypothalamus, where its signals satiety- that the individual has had enough to eat. Oddly, the blood that the individual has had enough to eat. Oddly, the blood of obese individuals may be rich in leptin. It may be of obese individuals may be rich in leptin. It may be possible that the leptin that they produce is ineffective possible that the leptin that they produce is ineffective because of a genetic mutation, or else their hypothalamic because of a genetic mutation, or else their hypothalamic cells lack a suitable number of receptors for leptin.cells lack a suitable number of receptors for leptin.

Growth factorsGrowth factors

Many different types of organs and cells produce peptide growth factors, which Many different types of organs and cells produce peptide growth factors, which stimulate cell division and mitosis. Some, like lymphokines are released into the stimulate cell division and mitosis. Some, like lymphokines are released into the blood; others diffuse into nearby cells. These growth factors include:blood; others diffuse into nearby cells. These growth factors include:

Granulate and macrophage colony-stimulating factor (GM-CSF) is secreted by Granulate and macrophage colony-stimulating factor (GM-CSF) is secreted by many different tissues. GM-CSF causes bone marrow stem cells to form either many different tissues. GM-CSF causes bone marrow stem cells to form either granulocyte or macrophage cells (both are forms of white blood cells), depending granulocyte or macrophage cells (both are forms of white blood cells), depending on whether the concentration is high.on whether the concentration is high.

Platelet –derived growth factor is released from platelets and from many other cell Platelet –derived growth factor is released from platelets and from many other cell types. It helps in wound healing and causes an increase in the number of types. It helps in wound healing and causes an increase in the number of fibroblasts, smooth muscle cells, and certain cells of the nervous system.fibroblasts, smooth muscle cells, and certain cells of the nervous system.

Epidermal growth factor and nerve growth factor stimulate the cells indicated by Epidermal growth factor and nerve growth factor stimulate the cells indicated by their names, as well as many others. These growth factors are also important in their names, as well as many others. These growth factors are also important in wound healing. wound healing.

Tumor angiogenesis factor stimulates the formation of capillary networks and is Tumor angiogenesis factor stimulates the formation of capillary networks and is released by tumor cells. One treatment for cancer is to halt the activity of this released by tumor cells. One treatment for cancer is to halt the activity of this growth factor.growth factor.

ProstaglandinsProstaglandinsProstaglandins are potent chemical signals produced within cells by Prostaglandins are potent chemical signals produced within cells by arachidonate, a fatty acid. Prostaglandins aren’t distributed in the arachidonate, a fatty acid. Prostaglandins aren’t distributed in the blood. Instead, they work close to where they’re produced. In the blood. Instead, they work close to where they’re produced. In the uterus, prostaglandins cause muscles to contract and are involved uterus, prostaglandins cause muscles to contract and are involved with the pain and discomfort of menstruation. They also mediate the with the pain and discomfort of menstruation. They also mediate the effects of pyrogens, chemicals that are believed to reset the effects of pyrogens, chemicals that are believed to reset the temperature regulatory center in the brain. For example, aspirin temperature regulatory center in the brain. For example, aspirin reduces body temperature and controls pain because of its effect on reduces body temperature and controls pain because of its effect on prostaglandins. Some prostaglandins can reduce gastric and have prostaglandins. Some prostaglandins can reduce gastric and have been used to treat ulcers. Others lower blood pressure and have been used to treat ulcers. Others lower blood pressure and have been used to treat hypertension. And others still inhibit platelet been used to treat hypertension. And others still inhibit platelet aggregation and have been used to prevent thrombosis (the aggregation and have been used to prevent thrombosis (the formation of stationary clots in blood vessels). However, different formation of stationary clots in blood vessels). However, different prostaglandins have contrary effects, and it’s very difficult to prostaglandins have contrary effects, and it’s very difficult to standardize their use. standardize their use.

Effects of AgingEffects of Aging

TThyroid disorders and diabetes are the most significant endocrine hyroid disorders and diabetes are the most significant endocrine problems affecting health and function as we age. Both hypo- and problems affecting health and function as we age. Both hypo- and hyperthyroidism are seen in the elderly. Graves’ disease is an hyperthyroidism are seen in the elderly. Graves’ disease is an autoimmune disease that targets the thyroid, resulting in symptoms of autoimmune disease that targets the thyroid, resulting in symptoms of cardiovascular disease, increased body temperature and fatigue. A cardiovascular disease, increased body temperature and fatigue. A person may also experience weight loss of as much a 20 pounds, person may also experience weight loss of as much a 20 pounds, depression and mental confusion. Hypothyroidism (myxedema) may fail depression and mental confusion. Hypothyroidism (myxedema) may fail to be diagnosed because they symptoms may simply be attributed to to be diagnosed because they symptoms may simply be attributed to the process of aging (hair loss, mental deterioration, and skin changes). the process of aging (hair loss, mental deterioration, and skin changes). The true incidence of IDDM (insulin-dependent, commonly referred to The true incidence of IDDM (insulin-dependent, commonly referred to as Type-1 diabetes) diabetes among the elderly is unknown. Its as Type-1 diabetes) diabetes among the elderly is unknown. Its symptoms can be confused with those of other medical conditions that symptoms can be confused with those of other medical conditions that are present.. As in all adults, NIDDM (non-insulin-dependent, mellitus are present.. As in all adults, NIDDM (non-insulin-dependent, mellitus type-2 diabetes) diabetes is associated with being overweight and type-2 diabetes) diabetes is associated with being overweight and often can be controlled by proper diet. often can be controlled by proper diet.

Medical focusMedical focusSide Effects of Anabolic SteroidsSide Effects of Anabolic Steroids

The story amazed major league baseball across the world; baseball sluggers - homerun hitters who had set new records The story amazed major league baseball across the world; baseball sluggers - homerun hitters who had set new records for baseball – were implicated in a scandal involving abuse of anabolic steroids. In testimony before the U.S. House of for baseball – were implicated in a scandal involving abuse of anabolic steroids. In testimony before the U.S. House of Representatives in March 2005, Mark McGwire of the St. Louis Cardinals, denied using steroids during his baseball career, Representatives in March 2005, Mark McGwire of the St. Louis Cardinals, denied using steroids during his baseball career, and stood by his hitting records. However, other players, most notably, Jose Canseco and Jason Giambi, admitted using and stood by his hitting records. However, other players, most notably, Jose Canseco and Jason Giambi, admitted using PED’s (performance-enhancing drugs). During the hearings, Congressional officials announced a ten-game suspension for PED’s (performance-enhancing drugs). During the hearings, Congressional officials announced a ten-game suspension for players who texted positive for steroids. Many legislators questioned whether the records created by those who tested players who texted positive for steroids. Many legislators questioned whether the records created by those who tested positive should be allowed to stand. The most tremendous concern to the general public, is the increased use of steroids positive should be allowed to stand. The most tremendous concern to the general public, is the increased use of steroids by teens wanting to bulk up quickly, probably wanting to be just like the athletes they admire. Anabolic steroids are by teens wanting to bulk up quickly, probably wanting to be just like the athletes they admire. Anabolic steroids are synthetic forms of testosterone. Taking doses 10 to 100 times the amount prescribed by doctors for illnesses promotes synthetic forms of testosterone. Taking doses 10 to 100 times the amount prescribed by doctors for illnesses promotes larger muscles when the person also exercises. Trainers were probably the first to acquire steroids for weight lifters, body larger muscles when the person also exercises. Trainers were probably the first to acquire steroids for weight lifters, body builders, and other athletes, like professional baseball players. However, being on steroids can have adverse effects. Men builders, and other athletes, like professional baseball players. However, being on steroids can have adverse effects. Men experience decreased sperm counts and decreased sexual desire due to reduction of the size of the testis. Some develop experience decreased sperm counts and decreased sexual desire due to reduction of the size of the testis. Some develop an enlarged prostate, or grow breasts. On the other hand, women can develop male sexual characteristics, such as hair an enlarged prostate, or grow breasts. On the other hand, women can develop male sexual characteristics, such as hair on their chests and faces, balding, and most experience and abnormal enlargement of the clitoris. Some stop ovulation on their chests and faces, balding, and most experience and abnormal enlargement of the clitoris. Some stop ovulation and/or menstruating, sometimes permanently. Researchers predict that two or three months of high-dosage use of and/or menstruating, sometimes permanently. Researchers predict that two or three months of high-dosage use of steroids as a teen can cause death by 30 or 40. Steroids have been linked to heart disease in both sexes and implicated steroids as a teen can cause death by 30 or 40. Steroids have been linked to heart disease in both sexes and implicated in the deaths of young athletes from liver cancer and kidney problems. Steroids cause the body to retain fluid, which in the deaths of young athletes from liver cancer and kidney problems. Steroids cause the body to retain fluid, which results in increased blood pressure. Users normally try to get rid of “steroid bloat” by taking large doses of diuretics (A results in increased blood pressure. Users normally try to get rid of “steroid bloat” by taking large doses of diuretics (A diuretic is any substance that promotes the production of urine. All diuretics increase the excretion of water from bodies, diuretic is any substance that promotes the production of urine. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way). A young California weight lifter had a fatal heart attack after using although each class does so in a distinct way). A young California weight lifter had a fatal heart attack after using steroids, and the post-mortem report showed a lack of electrolytes, salts that help regulate the heart. And lastly, steroid steroids, and the post-mortem report showed a lack of electrolytes, salts that help regulate the heart. And lastly, steroid abuse has psychological effects, like depression, hostility, aggression, and eating disorders. Unfortunately, these drugs abuse has psychological effects, like depression, hostility, aggression, and eating disorders. Unfortunately, these drugs cause the user to feel invincible. One particular abuser had his friend record him as he drove his car at 40 miles an hour cause the user to feel invincible. One particular abuser had his friend record him as he drove his car at 40 miles an hour into a tree. (Look at fig 10B). The FDA (Federal Food and Drug Administration now bans most steroids, and steroid use has into a tree. (Look at fig 10B). The FDA (Federal Food and Drug Administration now bans most steroids, and steroid use has been banned by the National Collegiate Athletic Association (NCAA), the National Football League (NFL), and the been banned by the National Collegiate Athletic Association (NCAA), the National Football League (NFL), and the International Olympic Committee (IOC).International Olympic Committee (IOC).

Homeostasis Homeostasis

The endocrine system works alongside of the nervous The endocrine system works alongside of the nervous system to form the control systems of the body. The system to form the control systems of the body. The nervous system provides a very fast and narrowly targeted nervous system provides a very fast and narrowly targeted system to turn on specific glands and muscles throughout system to turn on specific glands and muscles throughout the body. The endocrine system, on the other hand, is the body. The endocrine system, on the other hand, is much slower acting, but has very widespread, long lasting, much slower acting, but has very widespread, long lasting, and powerful effects. Hormones are distributed by glands and powerful effects. Hormones are distributed by glands through the bloodstream to the entire body, affecting any through the bloodstream to the entire body, affecting any cell with a receptor for a particular hormone. Most cell with a receptor for a particular hormone. Most hormones affect cells in several organs or throughout the hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful entire body, leading to many diverse and powerful responses.responses.

Hormonal regulationHormonal regulation

The levels of hormones in the body can be regulated by several factors. The levels of hormones in the body can be regulated by several factors. The nervous system can control hormone levels through the action of The nervous system can control hormone levels through the action of the hypothalamus and its releasing and inhibiting hormones. For the hypothalamus and its releasing and inhibiting hormones. For example, TRH produced by the hypothalamus stimulates the anterior example, TRH produced by the hypothalamus stimulates the anterior pituitary to produce TSH. Tropic hormones provide another level of pituitary to produce TSH. Tropic hormones provide another level of control for the release of hormones. For example, TSH is a tropic control for the release of hormones. For example, TSH is a tropic hormone that stimulates the thyroid gland to produce T3 and T4. hormone that stimulates the thyroid gland to produce T3 and T4. Nutrition can also control the levels of hormones in the body. For Nutrition can also control the levels of hormones in the body. For example, the thyroid hormones T3 and T4 require 3 or 4 iodine atoms, example, the thyroid hormones T3 and T4 require 3 or 4 iodine atoms, respectively, to be produced. In people lacking iodine in their diet, they respectively, to be produced. In people lacking iodine in their diet, they will fail to produce sufficient levels of thyroid hormones to maintain a will fail to produce sufficient levels of thyroid hormones to maintain a healthy metabolic rate. Finally, the number of receptors present in cells healthy metabolic rate. Finally, the number of receptors present in cells can be varied by cells in response to hormones. Cells that are exposed can be varied by cells in response to hormones. Cells that are exposed to high levels of hormones for extended periods of time can begin to to high levels of hormones for extended periods of time can begin to reduce the number of receptors that they produce, leading to reduced reduce the number of receptors that they produce, leading to reduced hormonal control of the cell. hormonal control of the cell.