biology test 3: the endocrine system
Estrogen exerts negative feedback on the pituitary early in the ovarian cycle. However, during days __-__ estrogen is a positive feedback signal, and causes a surge of LH and FSH. The LH surge causes the follicle to release its egg and to develop the corpus luteum. The corpus luteum functions as an endocrine gland and secretes estrogen and progesterone. These sex steroids exert negative feedback on the pituitary, inhibiting GnRH and new follicle maturation. Without fertilization, the corpus luteum degenerates, steroids decrease, and GnRH, FSH, and LH rise for the next cycle.
12-14
Sex determination Until the ____ week of a human embryo's development, either sex may develop. In mammals, the Y chromosome causes the gonads to start producing androgens and in the seven-week-old human embryo the male reproductive system develops. If androgens are not released, the female reproductive system develops. In _____, the opposite rules apply: male features are produced unless estrogens are present to trigger female development.
7th birds
Under non-stress conditions cortisol and other glucocorticoid release is controlled by ____ from the anterior pituitary which, in turn is controlled by adrenocorticotropin-releasing hormone from the hypothalamus. Turning off the cortisol stress response is also critical to avoid the consequences of long-term stress. Cortisol has a negative feedback effect on the _______ that decreases the release of adrenocorticotropin-releasing hormone. Higher areas of the brain also control ACTH-RH (stress, daily circadian cycle)
ACTH hypothalamus
______ disease is caused by the parasite Trypanosoma cruzi, transmitted by "kissing bugs", Rhodnius prolixus and related (reduvid) bugs. Common in South and Central America. Some occurance in southern U.S.A. decapitation was done 1 hour and 1 week after a blood meal 1 hour- 1 week- if the one hour and one week are joined by a glass tube conclusion: a blood meal stimulates production of some substance in the insect's head and then diffuses slowly through the body, triggering a molt
Chagas does not molt molts into an adult they both molt into an adult
Endocrine Pancreas Insulin and glucagon are produced in the pancreas in cell clusters called ______ __ ______. Several cell types have been identified in the islets: _____ (_) cells produce and secrete insulin. _____ (_) cells produce and secrete glucagon (antagonist of insulin). _____ (_) cells produce somatostatin. The remainder of the pancreas acts as an exocrine gland with digestive functions.
Islet of Langerhans beta (b) alpha (a) delta (d)
The gonads (testes and ovaries) produce steroid hormones synthesized from cholesterol. _____ are male steroids, the dominant one being _____. _____ and _____ are female steroids, the dominant estrogen being _____. Sex steroids determine whether a fetus develops into a male or female. After birth, sex steroids control maturation of sex organs and secondary sex characteristics such as breasts and facial hair.
adrogens testosterone estrogens and progesterone estradiol
Epinephrine and norepinephrine are ____ hormones. They bind to 3 types of receptors in target cells: α-adrenergic, b-adrenergic and γ. There are multiple forms of each of these. The ____ and ______ of receptors on a target cell have major effects on the response of the cell to epi and norepi.These can vary with time and physiological state. Norepi- acts mostly on the _ type and epi- with _, so drugs called beta blockers, which inactivate only b-adrenergic receptors, can be used to reduce fight-or-flight (stress) responses to ______. The beta blockers leave the alpha sites open to norepinephrine and its regulatory functions.
amine types and numbers a, b epi
Synthetic androgens (______ steroids) can exaggerate body strength and muscle development. Negative side effects in females include more masculine body features, such as shrinking the uterus and causing an irregular menstrual cycle. In males, the negative side effects include shrinking of the testes, enlarged breasts, and sterility. Continued use of anabolic steroids may increase risk of heart disease, some cancers, kidney damage, and personality disorders.
anabolic
testes: secrete: (1)
androgens
Posterior Pituitary The posterior pituitary releases two hormones: _______ hormone (vasopressin) and ______. They are made by neurons in the hypothalamus (and therefore are ______), and are packaged in vesicles. The vesicles are transported down the axons of the neurons that made them and are stored in the posterior pituitary.
antidiuretic oxytocin neurohormones
Water Soluble Hormones The receptors for water-soluble proteins are large glycoproteins on the cell surface with three domains: A _____ domain projecting outside the plasma membrane A ______ domain that anchors the receptor in the membrane A ______ domain that extends into the cytoplasm of the cell The cytoplasmic domain initiates the target cell's response by activating ____ _____ or ____ _____ (signal transduction cascades).
binding transmembrane cytoplasmic protein kinases or protein phosphates
After fertilization, in the oviduct: The zygote undergoes cell division and becomes a ______. The blastocyst moves down the oviduct and attaches to the lining of the uterus, the endometrium. Implantation occurs when the blastocyst burrows into the endometrium.
blastocyst
Two hormones work together in insects to regulate molting: _____ hormone and _____ (molting hormone). Cells in the brain produce brain hormone which is stored in a pair of structures attached to the brain called the ____ ______. After appropriate stimulation (e.g., a blood meal for Rhodnius), the c.c. release ____ hormone (also known as prothoracicotropic hormone, ____), which diffuses to an endocrine gland in the thorax called the _____ gland. The prothoracic gland releases _____ which stimulates molting.
brain hormone and ecdysone corpora cardiaca brain PTTH prothoracic ecdysone
Control of Blood (Ca++) Calcium levels in the blood must be regulated within a narrow range. Small changes in blood calcium levels have serious effects. Three hormones control (Ca++): ______, _______ ______ and _____ _. Most calcium in the body is in the bones (__%). About _% is in the cells, and only __% is in the extracellular fluids. Blood calcium levels are regulated by these processes: - ______ and _______ of bone ( a calcium phosphate mineral) -_______ of calcium by the kidneys -_______ of calcium from the digestive tract
calcitonin, parathyroid hormone, and vitamin D 99, 1 0.1 deposition and absorption excretion absorption
Adrenal cortex cells use _______ to produce three classes of steroid hormones called corticosteroids: ________ influence (raise) blood glucose concentrations and other aspects of fuel molecule metabolism. ________ influence extracellular ionic (especially Na+ and K+) balance. ___ ______ stimulate sexual development and reproductive activity. Under normal conditions these are secreted in only minimal amounts by the adrenal cortex. Since the adrenalcorticosteroids are obviously steroid hormones they act by stimulating transcription of certain genes. The main mineralocorticoid, ______, stimulates the kidney to conserve (reabsorb) ______ and excrete _____. It's release is stimulated by _____- __. Recall that the kidneys release renin (a proteolitic enzyme) into the blood. Renin cleaves a peptide, angiotensin-I, from circulating angiotensinogen. Angiotensin converting enzyme (ACE) (released into the blood by endothelial cells) converts angio-I to angiotensin-II. Renin release is stimulated by lo blood Na+ and /or lo blood pressure.
cholesterol glucocorticoids mineralcorticoids sex steroids aldosterone sodium potassium angiotensin-II
Vitamin D is not a true vitamin. It is made in skin cells (from _____, stimulated by _____ _____), circulates in the blood, and acts on distant target cells; therefore it is a hormone. Vitamin D itself is not very active, but in the _____ it receives an -OH group and in the _____ another -OH to become (1, 25) Dihydroxyvitamin D (1,25 dihydroxycholcalciferol), the active form. ___ stimulates the final step in the kidneys. The active form binds to _______ receptors and forms transcription factors. In the digestive tract the transcription factors act to increase synthesis of calcium pumps, calcium channels, and calcium-binding proteins, promoting uptake of calcium. In the kidneys, vitamin D acts with PTH to _____ calcium loss in urine. In bone vitamin D acts like PTH to stimulate bone turnover and the liberation of calcium The overall action of vitamin D is to raise blood calcium levels. Vitamin D also acts in a negative feedback loop to inhibit transcription of the ____ ____ in the parathyroid glands
cholesterol, ultraviolet light liver kidneys PTH cytoplasmic decrease PTH gene
Hormones and Their Actions Chemical messages, such as hormones, produce and coordinate anatomical, physiological, developmental and behavioral changes. Hormones are secreted by endocrine cells (often in endocrine glands). In the case of _______ hormones, the hormones diffuse into the extracellular fluid, and are distributed by the circulatory system. Hormones work more slowly than nerve impulses and therefore are less useful for controlling very rapid actions. Among many other things, hormones coordinate longer-term developmental processes such as reproductive cycles.
circulating
The distance over which the signal operates distinguishes hormone groups; some act close to the release site, others at distant body locations. most are _____ hormones some are local hormones ______ hormones act on the secreting cell itself. ______ hormones act on cells near the site of release.
circulating autocrine paracrine
Antidiuretic Hormone, Vasopressin The major function of antidiuretic hormone (ADH) is to increase water ______ by the kidney. If there is a high level of ADH secretion, the kidneys resorb water, ______ urine output. ADH stimulates increased ______ in the collecting ducts. If there is a low level of ADH secretion, the kidneys release water in dilute, high volume urine. ADH release by the posterior pituitary _____ if blood pressure falls or blood becomes too salty. ADH also causes peripheral blood vessel ______ to help elevate blood pressure and consequently is also called vasopressin.
conservation decreasing aquaporins increases constriction
The main glucocorticoid, ______, helps to control blood levels of glucose and other energy sources, and to mediate the body's response to stress. Cortisol has numerous, complex effects: - ____ blood (glucose) by (a) stimulating gluconeogenesis by the liver and (b) inhibiting peripheral use of glucose (saves glucose for neural tissue). - mobilizes fatty acids from adipose tissue into the blood. - increases blood (amino acid), from muscle etc., for uptake and use in gluconeogenesis by liver. The stress (fight-or-flight) response ensures that muscles have adequate glucose for immediate response (due to epinephrine), but then cortisol spares glucose for the brain and switches other tissue to ___ (and amino acid) metabolism. Remember the time lag in cortisol effects, especially compared to epi-. Cortisol also blocks the immune system reactions, which temporarily are less critical. Cortisol can therefore be used to reduce inflammation and allergic reactions.
cortisol raises fat
The numbers and types of hormone receptors on a cell can vary with time, season, development, drugs, physiological state, etc. resulting in up- or down-regulation. The abundance of hormone receptors can also be under negative feedback control. Continuous high levels of a hormone can ____ the number of its receptors. For example, high levels of insulin in type II diabetes mellitus result in a loss of insulin receptors.
decrease
Shell Formation in Bird Eggs A chicken egg shell contains ~2gm of Ca++ (as CaCO3), and is laid down in ~16hrs. Therefore Ca++ is deposited at a rate of ~125mg/hr. Total circulating blood Ca++ is ~25mg. Therefore every 12 minutes for 16 hrs an amount of Ca++ equal to the total circulating Ca++ is laid down in the shell by the shell gland. Source of Ca++? ______ and ______ ____ (only found in "laying" females, formation stimulated by estrogens and androgens). How? Remember, abnormal blood (Ca++) is quickly lethal. Mobilization of medullary bone is under the exquisite control of PTH.
diet and medullary bone
A _____-_____ _____ shows the threshold dose of a hormone needed to get a response and the dose that produces the maximum response. The dose that stimulates half the maximum response indicates the _____ of the target cell, tissue, organ, or animal to the hormone.
dose-response sesitivity
Hormonal communication arose _____ in evolution All multicellular animals have chemical communication between cells, even sponges. Plants also have hormones, mainly to control _____ and _______.
early growth development
_______ refers to cells or glands that do not have ducts leading to the outside of the body; they secrete their products directly into the extracellular fluid. (______ glands have ducts that release their secretions into the gut, etc.) Some endocrine cells are single cells within a tissue. Digestive hormones, for example, are secreted by isolated endocrine cells in the wall of the stomach and small intestine. Some endocrine cells aggregate into secretory organs called ______ ______. In vertebrates, several major endocrine glands make up the endocrine system.
endocrine exocrine endocrine glands
The uterine cycle parallels the ovarian cycle and consists of the buildup and breakdown of the _____. The endometrium remains prepared for a blastocyst until about _ days after ovulation. Menstruation is the sloughing off of the endometrium through the vagina. Most other mammals do not menstruate; the uterine lining is reabsorbed. _____ is a state of sexual receptivity around the time of ovulation.
endometrium 9 estrus
The adrenal medulla produces epinephrine (adrenaline) and norepinephrine (noradrenaline), mostly ____ in mammals. Release of these is increased in response to stress, initiating fight-or-flight reactions that affect: (1) the _______ system (i.e., increased heart rate and stroke volume and elevated blood pressure) and respiration (increased breathing rates) to enhance gas exchange and nutrient delivery. (2) increased glucose and fatty acid availability for ______.
epi cardiovascular metabolism
adrenal medulla: secretes: (2)
epi norepi
ovaries: secrete: (2)
estrogens progesterone
Some Effects of Diabetes Mellitus ______ urine production. High glucose levels in the blood result in such high (glucose) in the kidney tubules that significant amounts of glucose are not reabsorbed, resulting in an increased osmotic pressure in the tubules that in turn inhibits water reabsorption and causes excessive urine volume. The term "diabetes" refers to this high urine output which in untreated individuals results in ________. Diabetes insipidus is caused by hypo-secretion of _______ _____. Cells not taking up glucose use fat and protein for fuel, resulting in the body's wasting away and tissue and organ damage. - "Starvation in the midst of plenty"
excessive dehydration antidiuretic hormone
Thyrotropin-releasing hormone (TRH) was the _____ releasing hormone extracted from the hypothalamus. It causes anterior pituitary cells to release _______, which in turn stimulates the ______ gland. Gonadotropin-releasing hormone (GnRH) causes the anterior pituitary to release tropic hormones that control gonad activity (______ _______ hormone and _____ hormone). Now many more hypothalamic neurohormones are known. Can stimulate or inhibit release
first thyrotropin thyroid follicle stimulating and lutenizing
An ovarian cycle is about 28 days long in the human female. The functional unit of the ovary is called the _____ that consists of a ______ ______ and its surrounding ______ ______. After ____ weeks of follicular growth, ovulation occurs: the follicle ruptures and the egg is released. In the second half of the cycle, ovarian cells (corpus luteum) develop endocrine functions that stop if the egg is not fertilized. The corpus luteum functions as an endocrine gland and produces estrogen and progesterone for about ___ weeks. It degenerates unless a blastocyst implants in the endometrium.
follicle primary oocyte, ovarian cells two two
stomach lining: secretes: (1)
gastrin
Lipid-Soluble Hormones The receptors for lipid-soluble hormones are generally inside cells, either in the cytoplasm or in the nucleus. The action of lipid-soluble hormones is mediated by intracellular hormone receptors that usually alter ____ ______. Therefore, they are usually ____ acting than water soluble hormones, but their effects last _____. signal-> cytoplasm-> receptor+chaperone protein-> lose chaperone protein-> go to nucleus as transcription factor
gene expression slower longer
adrenal cortex: secretes: (3)
glucorticoids meralcorticoids sex steroids (minimally)
A ______ is an enlarged thyroid gland associated with either very low (_______) or very high (_______) levels of thyroxine. A thyroid follicle is a layer of epithelial cells surrounding a volume of glycoprotein called _______. Thyroglobulin contains iodinated tyrosines and is digested by the epithelial cells to make _____. If there is inadequate _____ present when thyroglobulin is made, the released molecules will be neither T3 nor T4 and will not bind to appropriate receptors (including those in the hypothalamus and anterior pituitary). Goiter occurs when thyroglobulin production is above normal and the follicles are enlarged. _______ goiter results when there is insufficient functional thyroxine to turn off TSH production. The most common cause is a deficiency of dietary iodine, once fairly common in the interior regions of the continents where access to seafood was restricted. With high TSH levels, the thyroid gland continues to produce nonfunctional thyroxine and becomes very large. The symptoms of this condition are ___ metabolic rate, ____ intolerance, and _____ and ______ sluggishness. Hyperthyroid goiter results when the negative feedback mechanism fails even though blood levels of thyroxine are high. A common cause is an ________ _______ in which an antibody to the ____ ______ is produced. This antibody binds the TSH receptor, causing the thyroid cells to release excess thyroxine. The thyroid remains maximally active and grows larger, causing symptoms associated with ___ metabolic rates.
goiter hypothyroidism, hyperthyroidism thyroglobulin thyroxine iodine hypothyroid low cold, physical and mental autoimmune disease TSH receptor high
Paracrine hormones They are released in tiny amounts, or are inactivated rapidly by enzymes, or are taken up efficiently by local cells. They don't generally get into the circulatory system. example of a paracrine hormone: _____ _____ Growth factors also act as ______ hormones: Some of the hormone influences the cell that secreted it, preventing the cell from secreting too much hormone. Neurons may technically be considered ______ cells because they use chemicals called neurotransmitters to send messages to another cell.
growth factors autocrine paracrine
_____ ______ (__) acts on many tissues to promote growth. GH stimulates cells to take-up ____ _____. GH also stimulates the liver to produce chemical messages (insulin-like growth factors) that stimulate ____ and ______ growth. ______ is the result of overproduction of GH in children. Underproduction of GH causes ______ ______. GH can now be produced by genetically engineered bacteria.
growth hormone (GH) amino acids bone and cartilage gigantism pituitary dwarfism
Hormone responses may also vary in their time course. The length of time for the concentration of a hormone to drop to one-half of the maximum is called its ___-____. *Half-life is partially determined by rate of _______ and _______ processes, along with rate of ______. Most hormones are broken down in the ____, removed from the blood by the ____, and excreted in the _____. The ability of the hormone to leave the blood affects its half-life. If the hormone is bound to _____ ______, it will have a longer half-life.
half-life degradation and elimination production liver kidney, urine carrier proteins
Additional hormones control pregnancy. After fertilization and implantation, cells covering the blastocyst secrete ___ ______ ______ (___), similar to __. This is the hormone detected by pregnancy tests. Effects of hCG: Corpus luteum continues to produce estrogen and progesterone. Endometrium is maintained and menstruation does not occur. After 2-3 months of pregnancy the placenta itself is the main source of estrogens and progesterone. (These prevent gonadotropin release from pituitary, thereby preventing another ovarian cycle. Mechanism of the "pill")
human chorionic gonadotropin (hCG) LH
Menstruation marks the beginning of both the ovarian and uterine cycles. A few days before menstruation: Pituitary _____ FSH and LH. Follicles in ovary grow and increase estrogen production. One follicle matures completely.
increases
After a meal, blood glucose levels rise and stimulate the b cells to release _____. Insulin (indirectly) stimulates cells to metabolize glucose and/or to convert it to glycogen and fat. When blood glucose levels fall, the pancreas decreases the release of insulin, and cells switch to using glycogen and fat for energy. If blood glucose falls too low, the a cells release glucagon which stimulates the liver to convert glycogen back to glucose (______).
insulin glycogenolysis
pancreas: secretes: (3)
insulin glucagon somatostatin
Many of the actions of growth hormone are antagonistic to those of _____ and similar to those of _____.
insulin, glucagon
The type of molt is determined by _____ hormone Wigglesworth also demonstrated that another hormone is responsible for determining whether an insect molts into an adult. By removing only the front part of the head, it was shown that the rear of the brain, containing the ____ _____, releases a substance _____ a molt to the adult stage. The substance is called juvenile hormone. If it is present, Rhodnius molts to another juvenile instar. Normally, during the ____ instar, the corpora allata stop making this hormone and the insect molts to the adult stage.
juvenile corpora allata preventing fifth
Hormonal control is only slightly more complex in insects having complete metamorphosis (larva to pupa to adult). An example is the silkworm moth. The egg hatches into a larva that has a high amount of _______ hormone in its body. As long as the level of juvenile hormone stays high, larvae molt into _____; when the juvenile hormone level wanes, _____ are formed. No juvenile hormone is found in the pupae, so they molt into ____.
juvenile larvae pupae adults
other organs, besides the endocrine glands, contain cells that produce and secrete hormones adipose tissue-> _____ heart->_______ _______ ________ kidney->_______, _______ stomach-> _______ intestine-> ______, _______ skin-> __________
leptin atrial natriuretic peptide Erythropoeitin, renin gastin secretin, colecystekinin vitamin D
Control of Sex Steroid Production Sex steroid production increases rapidly at puberty, or sexual maturation, in humans. Control of sex steroids (both male and female) is under control of the anterior pituitary tropic hormones called _____ _____ (__) and ______-_______ _______ (FSH). These gonadotropins are controlled by the ________ ________ ________ ________ (____). Before puberty, the hypothalamus produces low levels of GnRH. Puberty starts when the hypothalamus becomes less sensitive to _____ ______ by the sex steroids. GnRH release increases, stimulating gonadotropin production and, hence, sex steroid production. In females, increased LH and FSH at puberty induce the ovaries to begin female sex hormone production to initiate sexually mature body traits such as breast, vagina and uterus development, increase subcutaneous fat, initiation of the menstrual cycle, etc. In males, increased LH stimulates cells in the testes to make androgens which induce changes associated with adolescence such as facial hair, deeping voice, growth of penis and testes. Androgens also stimulate bone and muscle growth. Eventually close the epiphyseal plates, causing cessation of long bone growth.
luteinizing hormone (LH) and follicle-stimulating hormone (FSH) hypothalamic gonadotropin-releasing hormone (GnRH) negative feedback
The adrenal glands are made up of the adrenal ___ and the adrenal ____. The medulla produces ______ and ________. The medulla develops from the ______ system (sympathetic) and remains under its control. The cortex is under ____ control, mainly by __________ (especially for glucocorticosteroids) from the anterior pituitary.
medulla cortex epinephrine and norepinephrine nervous hormonal adrenocorticotropin (ACTH)
pinneal: secretes: (1)
melatonin
Thyroxine has many roles in regulating _______. It stimulates the transcription (______ receptors) of many genes in nearly all cells in the body. These include genes for enzymes of energy pathways, transport proteins, and structural proteins. It ______ metabolic rates in most cells and tissues (important in thermoregulation). It raises blood ______ and promotes the use of ______ over _____ for fuel. It promotes ______ ______ uptake and protein synthesis and so is critical for growth and development. Insufficient thyroxine after the __ month of human fetal life results in inadequate formation of the _____ _____ around the axons of neurons resulting in irreversible neural damage and retardation, ______.
metabolism cytoplasmic elevates glucose carbohydrates over fats amino acid 4th myelin sheath cretinism
Hormonal Control of Molting and Development in Insects Because insects have rigid exoskeletons, they have episodic growth patterns and must ____ periodically. The growth stage between each molt is called an ____. Experiments by British physiologist _____ showed how molting is triggered by a hormone from the brain.
molt instar Wigglesworth
The anterior pituitary cells and hypothalamus are under _______ feedback control by the hormones of the glands that they stimulate. causes short and long negative feedback loops For example, cortisol is produced by the adrenal gland in response to adrenocorticotropin. ACTH returns in the blood to the pituitary and/or hypothalamus, and inhibits further release of adrenocorticotropin. Cortisol also exerts negative feedback control on the hypothalamus, inhibiting release of adrenocorticotropin-releasing hormone, and on the pituitary. However, higher brain input to the hypothalamus also controls circulating anterior pituitary hormone levels.
negative
Insulin is required for glucose uptake by most cells, but not ____ cells. Insulin binds to receptors on the cell membrane and this stimulates glucose uptake. This glucose is then used as an energy source, stored as glycogen or converted to fat. Without insulin or the receptors, glucose accumulates to very high levels in the blood, and is lost in urine. Insulin also (1) inhibits _____ (lipid breakdown) in adipose tissue, and (2) stimulates _____ ____ uptake by cells. Diabetes mellitus is a disease caused by a lack of ____ (Type I) or a lack of _____ on target cells (Type II).
nerve lipase amino acid insulin receptors
The hypothalamus controls the anterior pituitary The anterior pituitary is controlled by ________ from the hypothalamus. The hypothalamus obtains data about body conditions and the external environment through both neuronal and hormonal signals. The hypothalamus and the anterior pituitary are connected by _____ _____ _____. Secretions from hypothalamic nerves are transported by these blood vessels to the anterior pituitary.
neurohormones portal blood vessels
The female reproductive cycle consists of two linked cycles: The _____ cycle that produces eggs and hormones. The _____ cycle that prepares the endometrium for a blastocyst. If a blastocyst does not arrive, the thickened endometrium sloughs off.
ovarian uterine
posterior pituitary: secretes: (2)
oxytocin antidiuretic hormone (ADH) (vasopressin)
parathryoids: secretes: (1)
parathyroid hormone
Anterior Pituitary The anterior pituitary releases four tropic hormones, which control (stimulate) activities of other endocrine glands. They are ______ and protein hormones; each is produced by a different type of pituitary cell. The four tropic hormones are: thyrotropin, adrenocorticotropin, and the two gonadotropins luteinizing hormone and follicle-stimulating hormone. Other peptide and protein anterior pituitary hormones influence tissues that are not endocrine glands. These include: growth hormone, prolactin, melanocyte-stimulating hormone, and the endogenous opiodes endorphins and enkephalins.
peptide
Other Digestive Track Hormones _____ __ - released by cells in small and large intestine. Also a brain neurohormone and neurotransmitter. - inhibits appetite (activity similar to leptin) _____ - Produced by cells in stomach and pancreas - stimulates appetite - also released by hypothalmus to stimulate GH release. Think about these as regards energy budget [energy (food) coming into body vs. energy lost], for example in: weight loss, exercise, sex differences, pregnancy.
peptide YY ghrelin
Hormones can be classified into three main groups based on structure: _____ or ______. They are water soluble and transported by vesicles out of the cell that made them, and their receptors are on the _____ of the cell membrane of the target cells (they can't get into the cells). _____ hormones are lipid-soluble and can diffuse out of the cell that made them but in the blood they must be bound to ____ _____. Because they can diffuse through the cell membrane their receptors are usually in the cytoplasm of the target cells. ____ hormones are derivatives of the amino acid _____. Most are water-soluble, but some are lipid-soluble.
peptides or proteins outside steroid carrier proteins amine, tyrosine
Bone minerals consist of both calcium and ______. When PTH stimulates the release of calcium from bone, phosphate is also released. Normal levels of calcium and phosphate in the blood are close to the concentration that could cause them to precipitate as _____ _____ ____. Calcium phosphate salts are involved in the formation of ____ _____ and hardening of artery walls. PTH acts on the kidneys to ______ the elimination of phosphate to reduce the possibility of calcium phosphate salt precipitation.
phosphate calcium phosphate salts kidney stones increase
Melatonin hormone is produced by the _____ gland, located between the cerebral hemispheres of the brain. Melatonin release occurs in the dark, marking the length of night. Exposure to light inhibits melatonin release. Melatonin is involved in biological rhythms, including ___________, the use of day length to track seasonal change and initiate appropriate physiological changes. In many animals, increasing day length signals the onset of reproductive behavior. Humans are not photoperiodic ?, but melatonin may be involved in daily rhythms (circadian) of the body (light/dark cycles).
pineal photoperiodicity
The ______ gland of vertebrates is a link between the nervous system and many endocrine glands and plays a crucial role in the endocrine system. The pituitary gland sits in a depression at the bottom of the skull and is attached to the hypothalamus. The pituitary is made of two parts: anterior and posterior. These are actually two separate organs. The posterior pituitary (_______) is an extension of the hypothalamus and therefore is neural tissue. The anterior pituitary (________) forms from an inpocketing of the roof of the mouth (_____ ____).
pituitary neurohypophysis adrenohypophysis Rathke's pouch
The four parathyroid glands are embedded in the _______ surface of the thyroid gland. Blood calcium decrease triggers release of _______ ______ (___), which causes an _______ in blood Ca++ by: 1. Causing the osteoclasts to dissolve bone and release calcium. 2. Promoting calcium reabsorbtion by the kidney to prevent loss in the urine. 3. Promoting vitamin D activation, which stimulates the gut to absorb calcium from food. Parathyroid hormone and calcitonin act ______ to regulate blood calcium levels.
posterior parathyroid hormone (PTH) increase antagonistically
Prolactin stimulates the _____ and, too a lesser extent, ______ of milk in female mammals. It is also important in pregnancy and, in males, has a role in controlling the ______ functions of the testes. However, in lower vertebrates it's functions are much different. ______ and _____ are the body's natural opiates. In the brain, these molecules also act as _______. Both as hormones and neurotransmitters they reduce pain in pain pathways.
production secretion endocrine endorphins and enkephalins neurotransmitters
many cell types: secrete: (1)
prostaglandins
Responses to Hormones Depend on their _____ and ____ _____ The same hormone can cause different responses in different types of cells. An example is epinephrine. The nervous system reacts to an emergency very quickly and stimulates adrenal cells to secrete epinephrine. The result is the fight-or-flight response. In the heart, it stimulates _____ (increases HR) and _______ (increases stroke volume) heartbeat to increase cardiac output. CO = HR x SV Blood vessels in some areas (gut, skin, etc.) ______ to send more blood to skeletal muscles. In the liver, glycogen is broken down to glucose to provide quick energy. In fat tissue, fats are mobilized as another energy source.
receptors target cells faster stronger constrict
Hypothalamus secretes:
releasing and release inhibiting hormones oxytocin, antidiuretic hormone
mice experiment: 2 strains of mice that become obese db/db and ob/ob the wild type is Ob; Db wild type conjoined with db/db- mice becomes skinny wild type conjoined with ob/ob- mice stays fat conclusion: ob/ob mice have a _____ _____ ______ problem db/db mice have a ______ problem Ob encodes for _____ Db encodes for the ______
satiety factor producing receptor leptin receptor
lining of small intestine: secretes: (3)
secretin cholecystokinin enterogastrone
Oxytocin A major function of oxytocin is to stimulate uterine _____ muscle contraction for the birth process. (_____) It also stimulates _____ _____ (stimulates smooth muscle for ejection of milk) in the mother's breasts. Suckling by the baby, or even the sight or sound of the baby, can cause the mother to secrete oxytocin and release milk.
smooth pitocin milk flow
In the pancreas, _______ has paracrine functions of inhibiting release of both insulin and glucagon. Outside of the pancreas, it _____ gut activities to extend the time of nutrient absorption. It also acts as a hypothalamic neurohormone inhibitor for the release of __ and _______ by the pituitary.
somatostatin slows GH and thyrotropin
Growth Hormone ______ long bone growth (cartilage), increasing thickness of the epiphyseal plate. _______ eventually closes the epiphyseal plate, stopping long bone growth.
stimulates testosterone
Cells receiving the hormonal message are called _____ cells and must have ______ ______. The binding of the receptor activates a response.
target appropriate receptors
thymus: secretes: (1)
thymosins
Calcitonin, released by the ______ gland, acts to _____ calcium levels in the blood. Bone is constantly remodeled by absorption of old bone and production of new bone. ______ break down bone and release calcium to the blood. ______ secrete the protein matrix and use circulating calcium to build new bone. As the bone is laid down the osteoblasts are surrounded and develop into _______. Calcitonin ______ osteoclast activity and ______ the osteoblasts to take up calcium from the blood for bone growth.
thyroid, lower osteoclasts osteoblasts osteocytes decreases, stimulates
anterior pituitary: secretes: 4 tropic hormones 4 other hormones
thyrotropin adrenocorticotropin (ACTH) luteinizing hormone (LH) follicle stimulating hormone (FSH) growth hormone (GH) prolactin melanocyte- stimulating hormone endorphins and enkephalins
Control of Thyroxine ______ (_____-______ _______) from the anterior pituitary activates thyroid gland cells to produce thyroxine. ______-______ _______ (___) from the hypothalamus activates TSH-producing cells in the anterior pituitary. In a negative feedback loop, thyroxine inhibits the response of _______ cells to ___. Therefore, less TSH is released when thyroxine levels are high, and more is released when levels are low. Thyroxin also feeds back to reduce ___ from the ________.
thyrotropin (thyroid stimulating hormone, TSH) Thyrotropin- releasing hormone (TRH) pituitary cells to TRH TRH from the hypothalamus
thyroid: secretes: (2)
thyroxine calcitonin
The thyroid gland, located near the ______, is another example of an endocrine gland that is controlled by negative feedback. The thyroid gland produces the hormone _______ in specialized structures called follicles. Two active forms of thyroxine, __ and __, are made from tyrosine. T3 (triiodothyronine) has three iodine atoms. T4 has four iodine atoms. More __ is produced, but it can be converted to __ by an enzyme in the blood. __ is the more active form of the hormone.
trachea thyroxine T3 and T4 T4, T3 T3
