Objective 1 - how the endocrine maintains homeostasis
The Hypothalamus- Pituitary Connection
•hypothalamus is a part of the brain connected to the pituitary gland; it monitors the state of the body’s internal environment and regulates pituitary gland activity.
•hypothalamus and pituitary directly linked by both neurons and blood vessels.
•these two structures act as a bridge between the nervous system and the endocrine system.
•together they control many physiological processes: metabolic rate, kidney function, appetite, mental alertness, reproduction, and growth and development.
•they secrete hormones that influence the activity of other hormone-producing glands.
The Endocrine System (Ch.13 pages 422-446)
•releases chemical substances (hormones) to be circulated in the blood.
•helps maintain homeostasis by causing or preventing change in specific tissues /organs of the body.
•the nervous and endocrine systems work together; the endocrine system, utilizing chemical messengers, works more slowly, but is more enduring (lasts longer), while the nervous system is fast (but quickly is over), using an electro-chemical messaging system. As well, the endocrine system reaches out through the blood, whereas the nervous system uses neurons to send the message.
•some regulatory functions include control of heart rate, blood pressure, immune response to infection, reproduction...
Objective 2 - hormones and target organs
Hormones
•chemical substances that circulate through the blood and exert some measure of control over various tissues/organs of the body.
•do not seek out organs; organs await the arrival of the hormone.
•http://www.youtube.com/watch?v=FTftmC_eDTs – target cells
Target cells
•cells that react to a particular hormone
•contain specific receptors that fit the hormone in lock and key fashion.
Objective 3 - Steroid and Non-steroid Hormones
Types of hormones
•1. steroid hormones
–manufactured from cholesterol - Cortisol & Progesterone
–fat soluble steroid hormones can easily pass through the
cell membrane of a target cell.
–hormone then attaches to a protein receptor in the cytoplasm -> hormone receptor complex.
–complex enters nucleus, where it binds with and activates a gene on the cell’s DNA.
–Once ‘turned on’ the gene produces enzyme that causes chemical reactions within the cell. (see Fig. 13.5, p. 425)
2. non-steroid hormones (called first messenger)
•composed of either proteins, peptides or amino acids; i.e. not fat soluble, so do not enter cells to exert effect.
•they bind to receptors in the surface of target cells. (lock and key)
•Once attached, it triggers a chain of chemical reactions within the cell
•Ex. With adrenaline, it causes an enzyme to convert ATP to cyclic AMP, (cAMP = second messenger), which activates an enzyme cascade causing glycogen in liver cells to convert to glucose so it can be used for energy.
Objectives 4 & 5 - Glands, Hormones, and Their Effects
Hypothalamus•Found in the brain, above the pituitary gland, and in front of the pineal
•Secretes “releasing factors” which stimulates other glands (mainly the pituitary) to release hormones
•Produces oxytocin and ADH which are stored and released by the posterior pituitary.
Pituitary Gland
•Considered the ‘master gland’
•Has hormones that regulates the release of other hormones in glands throughout the body.
•Composed of two glands – anterior and posterior.
•Their functions aren’t similar because they are derived from different parts of the body (anterior comes from cells in the roof of the mouth prenatally and the posterior is composed of neural tissue)
Posterior Pituitary
•Located at the back of the pituitary gland, below the hypothalamus
•Releases oxytocin – an increase causes uterine contractions during childbirth and causes the release of milk from the mammary glands
•Releases ADH (anti-diuretic hormone) – regulates the sodium in the bloodstream. ADH increases if you have high sodium, or if you lost blood, causing you to retain water.
Anterior Pituitary
•Located at the front of the pituitary gland, below the hypothalamus.
•It produces six hormones, four of which are tropic hormones.
•Prolactin – an increase stimulates the development of mammary gland tissue and milk production. (a breast-feeding baby will cause a greater release of prolactin)
•TSH (Thyroid stimulating hormone) – an increase in TSH causes more thyroxine to be released from the thyroid. When thyroxine levels are at homeostasis, the hypothalamus will stop requesting the release of TSH.
•HGH (Human growth hormone, or somatotropin) – regulates growth and development. Causes things like increased cell division and protein synthesis.
•ACTH (adrenocorticotropic hormone/corticotropin) – mostly controls cortisol levels in the adrenal cortex and has some control over aldosterone (also controlled by blood pressure)
Gonadotropins
•FSH (follicle stimulating hormone) – stimulates the testes to produce sperm and follicles of the ovaries to produce estrogen.
•LH (luteinizing hormone) stimulates testes to produce testosterone and corpus luteum to produce progesterone.
Pineal Gland
•Located in the brain, in the ear area, behind the hypothalamus.
•Melatonin levels rise at night as it becomes dark and are low during the day when it is bright out.
Thyroid
•Found in the neck – shaped like a butterfly
•Secretes thyroxine – which targets most cells of the body
•An increase in thyroxine increases basal metabolic rate (metabolism) and oxygen consumption.
•Also secretes calcitonin. When calcium levels are high in the blood, calcitonin increases, causing calcium to be stored by the body.
•The thyroid gland is stimulated by TSH (thyroid stimulating hormone)
Parathyroid
•Found embedded in the thyroid (four small glands in each corner of the ‘butterfly wings’)
•Releases PTH – parathyroid hormone (aka parathormone).
•PTH works the opposite of calcitonin. When calcium levels in the blood are too low, PTH increases causing bone tissue to release calcium into the blood.
Thymus
•Located in the chest, below the collarbone, between the lobes of the lungs.
•Produces thymosin – stimulates the production and maturing of lymphocytes into T cells.
•This gland normally disappears after puberty (the spleen and lymph glands produce lymphocytes then)
Kidney
•Located in the middle back, behind the pancreas
•Releases erythropoetin – which in involved in the production of red blood cells
•Also releases angiotensin – regulates blood pressure by constricting arterioles and stimulating the release of aldosterone from adrenal cortex
Adrenal
•Located on top of each kidney
•Has two parts, and outer cortex and inner medulla
•Cortex – releases cortisol, which increases glucose synthesis and aldosterone, which regulates the amounts of water and mineral salts in the blood, which regulates blood pressure (both steroid hormones)
•Also releases small amounts of testosterone and estrogen
•Medulla – adrenaline and noradrenaline
•Both are non-steroid hormones
•‘stress’ hormone
•The control of both hormones is regulated directly by the hypothalamus via the sympathetic nervous system (also act as neurotransmitters, but there effects are shorter lived)
•85:15 ratio of adrenaline to noradrenaline
•Increase heart rate, blood pressure, vasodilation, break down glycogen into glucose.
Pancreas
•Sandwiched between the stomach and kidneys
•Releases non-steroid hormones insulin and glucagon
•These hormones work together to regulate the body’s metabolism of sugar
•High levels of sugar stimulate insulin
•Low levels of sugar stimulate glucagon
Testes
•Found outside the body below the waist in males
•Steroid hormone testosterone
•Responsible for the development of secondary sex characteristics (enlargement of genitals and larnyx, promotes muscle growth and body hair
Ovaries
•Found inside the body (connected to the uterus) below the waist in females
•Responsible for puberty in females: enlargement of breasts, preparing the uterus for pregnancy during the menstrual cycle, pubic hair, widening of the pelvis
The Hypothalamus- Pituitary Connection
•hypothalamus is a part of the brain connected to the pituitary gland; it monitors the state of the body’s internal environment and regulates pituitary gland activity.
•hypothalamus and pituitary directly linked by both neurons and blood vessels.
•these two structures act as a bridge between the nervous system and the endocrine system.
•together they control many physiological processes: metabolic rate, kidney function, appetite, mental alertness, reproduction, and growth and development.
•they secrete hormones that influence the activity of other hormone-producing glands.
The Endocrine System (Ch.13 pages 422-446)
•releases chemical substances (hormones) to be circulated in the blood.
•helps maintain homeostasis by causing or preventing change in specific tissues /organs of the body.
•the nervous and endocrine systems work together; the endocrine system, utilizing chemical messengers, works more slowly, but is more enduring (lasts longer), while the nervous system is fast (but quickly is over), using an electro-chemical messaging system. As well, the endocrine system reaches out through the blood, whereas the nervous system uses neurons to send the message.
•some regulatory functions include control of heart rate, blood pressure, immune response to infection, reproduction...
Objective 2 - hormones and target organs
Hormones
•chemical substances that circulate through the blood and exert some measure of control over various tissues/organs of the body.
•do not seek out organs; organs await the arrival of the hormone.
•http://www.youtube.com/watch?v=FTftmC_eDTs – target cells
Target cells
•cells that react to a particular hormone
•contain specific receptors that fit the hormone in lock and key fashion.
Objective 3 - Steroid and Non-steroid Hormones
Types of hormones
•1. steroid hormones
–manufactured from cholesterol - Cortisol & Progesterone
–fat soluble steroid hormones can easily pass through the
cell membrane of a target cell.
–hormone then attaches to a protein receptor in the cytoplasm -> hormone receptor complex.
–complex enters nucleus, where it binds with and activates a gene on the cell’s DNA.
–Once ‘turned on’ the gene produces enzyme that causes chemical reactions within the cell. (see Fig. 13.5, p. 425)
2. non-steroid hormones (called first messenger)
•composed of either proteins, peptides or amino acids; i.e. not fat soluble, so do not enter cells to exert effect.
•they bind to receptors in the surface of target cells. (lock and key)
•Once attached, it triggers a chain of chemical reactions within the cell
•Ex. With adrenaline, it causes an enzyme to convert ATP to cyclic AMP, (cAMP = second messenger), which activates an enzyme cascade causing glycogen in liver cells to convert to glucose so it can be used for energy.
Objectives 4 & 5 - Glands, Hormones, and Their Effects
Hypothalamus•Found in the brain, above the pituitary gland, and in front of the pineal
•Secretes “releasing factors” which stimulates other glands (mainly the pituitary) to release hormones
•Produces oxytocin and ADH which are stored and released by the posterior pituitary.
Pituitary Gland
•Considered the ‘master gland’
•Has hormones that regulates the release of other hormones in glands throughout the body.
•Composed of two glands – anterior and posterior.
•Their functions aren’t similar because they are derived from different parts of the body (anterior comes from cells in the roof of the mouth prenatally and the posterior is composed of neural tissue)
Posterior Pituitary
•Located at the back of the pituitary gland, below the hypothalamus
•Releases oxytocin – an increase causes uterine contractions during childbirth and causes the release of milk from the mammary glands
•Releases ADH (anti-diuretic hormone) – regulates the sodium in the bloodstream. ADH increases if you have high sodium, or if you lost blood, causing you to retain water.
Anterior Pituitary
•Located at the front of the pituitary gland, below the hypothalamus.
•It produces six hormones, four of which are tropic hormones.
•Prolactin – an increase stimulates the development of mammary gland tissue and milk production. (a breast-feeding baby will cause a greater release of prolactin)
•TSH (Thyroid stimulating hormone) – an increase in TSH causes more thyroxine to be released from the thyroid. When thyroxine levels are at homeostasis, the hypothalamus will stop requesting the release of TSH.
•HGH (Human growth hormone, or somatotropin) – regulates growth and development. Causes things like increased cell division and protein synthesis.
•ACTH (adrenocorticotropic hormone/corticotropin) – mostly controls cortisol levels in the adrenal cortex and has some control over aldosterone (also controlled by blood pressure)
Gonadotropins
•FSH (follicle stimulating hormone) – stimulates the testes to produce sperm and follicles of the ovaries to produce estrogen.
•LH (luteinizing hormone) stimulates testes to produce testosterone and corpus luteum to produce progesterone.
Pineal Gland
•Located in the brain, in the ear area, behind the hypothalamus.
•Melatonin levels rise at night as it becomes dark and are low during the day when it is bright out.
Thyroid
•Found in the neck – shaped like a butterfly
•Secretes thyroxine – which targets most cells of the body
•An increase in thyroxine increases basal metabolic rate (metabolism) and oxygen consumption.
•Also secretes calcitonin. When calcium levels are high in the blood, calcitonin increases, causing calcium to be stored by the body.
•The thyroid gland is stimulated by TSH (thyroid stimulating hormone)
Parathyroid
•Found embedded in the thyroid (four small glands in each corner of the ‘butterfly wings’)
•Releases PTH – parathyroid hormone (aka parathormone).
•PTH works the opposite of calcitonin. When calcium levels in the blood are too low, PTH increases causing bone tissue to release calcium into the blood.
Thymus
•Located in the chest, below the collarbone, between the lobes of the lungs.
•Produces thymosin – stimulates the production and maturing of lymphocytes into T cells.
•This gland normally disappears after puberty (the spleen and lymph glands produce lymphocytes then)
Kidney
•Located in the middle back, behind the pancreas
•Releases erythropoetin – which in involved in the production of red blood cells
•Also releases angiotensin – regulates blood pressure by constricting arterioles and stimulating the release of aldosterone from adrenal cortex
Adrenal
•Located on top of each kidney
•Has two parts, and outer cortex and inner medulla
•Cortex – releases cortisol, which increases glucose synthesis and aldosterone, which regulates the amounts of water and mineral salts in the blood, which regulates blood pressure (both steroid hormones)
•Also releases small amounts of testosterone and estrogen
•Medulla – adrenaline and noradrenaline
•Both are non-steroid hormones
•‘stress’ hormone
•The control of both hormones is regulated directly by the hypothalamus via the sympathetic nervous system (also act as neurotransmitters, but there effects are shorter lived)
•85:15 ratio of adrenaline to noradrenaline
•Increase heart rate, blood pressure, vasodilation, break down glycogen into glucose.
Pancreas
•Sandwiched between the stomach and kidneys
•Releases non-steroid hormones insulin and glucagon
•These hormones work together to regulate the body’s metabolism of sugar
•High levels of sugar stimulate insulin
•Low levels of sugar stimulate glucagon
Testes
•Found outside the body below the waist in males
•Steroid hormone testosterone
•Responsible for the development of secondary sex characteristics (enlargement of genitals and larnyx, promotes muscle growth and body hair
Ovaries
•Found inside the body (connected to the uterus) below the waist in females
•Responsible for puberty in females: enlargement of breasts, preparing the uterus for pregnancy during the menstrual cycle, pubic hair, widening of the pelvis
Objective #6
A. Negative Feedback Loop
•Homeostatic mechanism that detects and fixes deviations from homeostasis.
•Uses sensory receptors, an integrator, and an effector
•Ex. TSH and thyroxine
•When thyroxine is low, hypothalamus uses releasing factors to trigger the anterior pituitary to secretes TSH ( thyroid stimulating hormone)
•TSH travels in the blood stream, connects to receptors on the thyroid, and triggers the release of thyroxine (increases metabolic rate, and oxygen consumption in target cells of heart, skeletal muscle, liver, and kidney; not many target cells in brain, spleen, and reproductive organs so not as much effect)
•Thyroxine increases to a point where it signals the hypothalamus to prevent the pituitary gland from producing TSH
•TSH secretion is inhibited, thereby reducing thyroid gland stimulation, etc....
•called negative feedback because it is a cycle in which the last step in a sequence inhibits the first step in the sequence.
6B. Positive Feedback Loop
•Oxytocin functions during and after childbirth
•Towards the end of pregnancy, baby’s head pushes against the cervix (‘drops down’)
•When the amniotic sac breaks, increased pressure is on the lower end of the uterus (cervix)
•Pressure receptors send impulses to the hypothalamus
•Hypothalamus triggers the posterior pituitary to release oxytocin
•Oxytocin causes the uterine walls to contract, increasing the pressure against the cervix
•This positive feedback process continues until the baby is born
Oxytocin - After Birth
•Suckling also triggers the release of oxytocin
•Therefore, oxytocin levels increase during breastfeeding, causing muscle contractions in the mammary ducts
•These contractions cause milk expulsion
Objective 7 - Regulation of Blood Glucose
•The body wants glucose maintained within a narrow range
•Insulin and glucagon are used to regulate blood sugar
•Insulin is secreted by the beta cells of the pancreas when blood sugar is high (i.e., after a meal)
•Insulin causes glucose to be absorbed by the liver (as glycogen), muscle cells, or adipose (fat tissue).
•As glucose is removed from circulation, blood sugar levels decreases to ‘normal’ (75-110mg/100mL)
•Glucagon is secreted by the alpha cells of the pancreas
•If blood glucose is low, (i.e., just before a meal), glucagon levels increase to make the liver release the glucose it has stored as glycogen.
Objective 8 - Disorders of the Endocrine System
Refer to the prezi links below, to supplement your notes on this topic.
http://prezi.com/e1p_1fkwjq0e/disorders-of-the-endocrine-system/?utm_campaign=share&utm_medium=copy
http://prezi.com/ska_xqzmahh0/untitled-prezi/?utm_campaign=share&utm_medium=copy
Objective 9 - Discovery of Insulin - p. 439
MacLeod supplied the lab, dogs and assistant Charles Best
What Banting Did...
Now let's try humans...
Objective 10 - Technologies (see file below)
A. Negative Feedback Loop
•Homeostatic mechanism that detects and fixes deviations from homeostasis.
•Uses sensory receptors, an integrator, and an effector
•Ex. TSH and thyroxine
•When thyroxine is low, hypothalamus uses releasing factors to trigger the anterior pituitary to secretes TSH ( thyroid stimulating hormone)
•TSH travels in the blood stream, connects to receptors on the thyroid, and triggers the release of thyroxine (increases metabolic rate, and oxygen consumption in target cells of heart, skeletal muscle, liver, and kidney; not many target cells in brain, spleen, and reproductive organs so not as much effect)
•Thyroxine increases to a point where it signals the hypothalamus to prevent the pituitary gland from producing TSH
•TSH secretion is inhibited, thereby reducing thyroid gland stimulation, etc....
•called negative feedback because it is a cycle in which the last step in a sequence inhibits the first step in the sequence.
6B. Positive Feedback Loop
•Oxytocin functions during and after childbirth
•Towards the end of pregnancy, baby’s head pushes against the cervix (‘drops down’)
•When the amniotic sac breaks, increased pressure is on the lower end of the uterus (cervix)
•Pressure receptors send impulses to the hypothalamus
•Hypothalamus triggers the posterior pituitary to release oxytocin
•Oxytocin causes the uterine walls to contract, increasing the pressure against the cervix
•This positive feedback process continues until the baby is born
Oxytocin - After Birth
•Suckling also triggers the release of oxytocin
•Therefore, oxytocin levels increase during breastfeeding, causing muscle contractions in the mammary ducts
•These contractions cause milk expulsion
Objective 7 - Regulation of Blood Glucose
•The body wants glucose maintained within a narrow range
•Insulin and glucagon are used to regulate blood sugar
•Insulin is secreted by the beta cells of the pancreas when blood sugar is high (i.e., after a meal)
•Insulin causes glucose to be absorbed by the liver (as glycogen), muscle cells, or adipose (fat tissue).
•As glucose is removed from circulation, blood sugar levels decreases to ‘normal’ (75-110mg/100mL)
•Glucagon is secreted by the alpha cells of the pancreas
•If blood glucose is low, (i.e., just before a meal), glucagon levels increase to make the liver release the glucose it has stored as glycogen.
Objective 8 - Disorders of the Endocrine System
Refer to the prezi links below, to supplement your notes on this topic.
http://prezi.com/e1p_1fkwjq0e/disorders-of-the-endocrine-system/?utm_campaign=share&utm_medium=copy
http://prezi.com/ska_xqzmahh0/untitled-prezi/?utm_campaign=share&utm_medium=copy
Objective 9 - Discovery of Insulin - p. 439
- Frederick Banting and Charles Best - Canadian
- Banting found a link between the pancreas and diabetes after reading a journal
- Dogs with pancreas' removed developed diabetic symptoms
- healthy pancreas had the islets of Langerhans
- if main duct of pancreas is blocked, islets still persist
- if islets remain healthy, no diabetes
- islets held teh key that allowed glucose to enter body's cells
MacLeod supplied the lab, dogs and assistant Charles Best
What Banting Did...
- blocked pancreatic duct
- chemically extracted the islet secretions
- injected into a dog that had it's pancreas removed (diabetes)
- hypothesis - extract will normalize the diabetic dog
- July 30, 1921 - hypothesis proven correct
- reaffirmed several times
Now let's try humans...
- first try with humans was unsuccessful
- 90% alcohol concentration used was too strong
- purer extract from islets was used, resulting in positive results
- Insulin was named after Latin word for "island"
- Banting and MacLeod - won the Nobel Prize for medicine
- shared the prize with Best and Collip
Objective 10 - Technologies (see file below)
technologies_that_prolong_and_terminate_life.docx | |
File Size: | 11 kb |
File Type: | docx |