Chapter 41: Animal Hormones Flashcards
(139 cards)
1
Q
Endocrinology
A
study of hormones and their actions
2
Q
Hormone
A
intercellular chemical messenger that travels within body tissue
3
Q
What do hormones travel between?
A
endocrine cells and target cells
4
Q
Endocrine cell function
A
produces and/or stores hormones
5
Q
Target cell
A
contains receptor molecules that bind to hormone molecules–>activates cellular mechanisms–>hormone = “message” and the target cell responds by either activating or inhibiting enzyme-catalyzed reactions–>results in activation of gene expression or protein synthesis
6
Q
What does the receptor-hormone activate?
A
secondary messenger systems (hormone = first messenger)
7
Q
Circulating hormones
A
transported by the blood and bind to receptors on distant cells
8
Q
Paracrine hormones
A
bind to receptors on nearby cells
9
Q
Autocrine systems
A
hormones bind on cells that secrete them
10
Q
Cells with no receptors
A
don’t respond to hormones
11
Q
What do neurons secrete?
A
chemical neurotransmitters that bind to receptors on other cells
12
Q
Local hormones
A
chemical message released into ECF, localized effects (paracrine, autocrine)
13
Q
Histamine
A
hormone released by mast cells, diffuses into damaged tissue to dilate local blood vessels as part of inflammation response
14
Q
Circulating hormone
A
a chemical message released into circulatory system with goal of reaching more distant cells
15
Q
How many actions can a single hormone have?
A
many
16
Q
Glands
A
organs composed of clusters of secretory cells
17
Q
Exocrine glands
A
release secretions to outside of the body through ducts (salivary, sweat)
18
Q
Endocrine glands
A
“ductless” glands that store and release hormones into ECF from which it may enter the body’s circulatory systems
19
Q
What kind of environment does homeostasis maintain?
A
stable internal environment (within cells and systems)
20
Q
What mediates homeostasis?
A
nervous and endocrine systems
21
Q
what kind of regulation does homeostasis involve?
A
feedback regulation
22
Q
what is the goal of homeostasis?
A
to prevent harmful fluctuations
23
Q
how many endocrine glands?
A
9
24
Q
What kinds of cells secrete hormones?
A
nerve cells, digestive tract cells, mast cells in tissue
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Histamine
hormone released by mast cells, diffuses into damaged tissue to dilate local blood vessels as part of the inflammation response
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```
Hypothalamus
HORMONE = Release and Release-inhibiting
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. peptides
2. anterior pituitary
3. control secretion of hormones of anterior pituitary
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Hypothalamus
HORMONE = Oxytocin, antidiuretic
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptides
2. Anterior pituitary
3. Stored and released by posterior pituitary
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Anterior pituitary: Tropic hormones
HORMONE=Thyrotropin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Glycoprotein
2. Thyroid gland
3. Stimulates synthesis and secretion of thyroxine
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Anterior pituitary
HORMONE=Adrenocorticotropin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Polypeptide
2. Adrenal cortex
3. Stimulates release of hormones from adrenal cortex
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Anterior pituitary
HORMONE=Luteinizing
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Glycoprotein
2. Gonads
3. Stimulates secretion of sex hormones from ovaries and testes
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```
Anterior Pituitary
HORMONE=Follicle-stimulating
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Glycoprotein
2. Gonads
3. Stimulates growth and maturation of eggs in females; stimulates sperm production in males
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Anterior Pituitary
HORMONE=Growth
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Protein
2. Bones, liver, muscles
3. stimulates protein synthesis and growth
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Anterior pituitary
HORMONE=Prolactin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Protein
2. Mammary glands
3. Stimulates milk production
34
Hormone= melanocyte-stimulating
1. chemical nature
2. target(s)
3. Important properties or actions
1. Peptide
2. Melanocytes
3. controls skin pigmentation
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Hormone=endorphins and enkephalins
1. chemical nature
2. target(s)
3. Important properties or actions
1. Peptides
2. Spinal cord neurons
3. decrease painful sensations
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Posterior Pituitary
HORMONE=Oxytocin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Uterus, breasts
3. induces birth by stimulating labor contractions; causes milk flow
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Posterior Pituitary
HORMONE=Antidiuretic
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Kidneys
3. Stimulates water reabsorption and raises blood pressure
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```
Thyroid
HORMONE=Thyroxine
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Iodinated amino acid derivative
2. Many tissues
3. stimulates and maintains metabolism necessary for normal development and growth
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Thyroid
HORMONE=Calcitonin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Bones
3. Stimulates bone formation; lowers blood calcium
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```
Parathyroids Thymus
HORMONE=Parathormone
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Protein
2. Bones
3. Stimulates bone formation; lowers blood calcium
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```
Parathyroids Thymus
HORMONE=Thymosins
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptides
2. Immune system
3. Activate immune responses of T cells in the lymphatic system
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```
Pancreas
HORMONE=Insulin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. protein
2. muscles, liver, fat, other tissues
3. stimulates uptake and metabolism of glucose; increases conversion of glucose to glycogen and fat
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```
Pancreas
HORMONE=Glucagon
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Protein
2. Liver
3. Stimulates breakdown of glycogen and raises blood sugar
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Pancreas
HORMONE=Somatostatin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Digestive tract; other cells of the pancreas
3. Inhibits insulin and glucagon release; decreases secretion, motility, and absorption in the digestive tract
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Adrenal medulla
HORMONE=Epinephrine, norepinephrine
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. modified amino acids
2. heart, blood vessels, liver, fat cells
3. Stimulate fight-or-flight reactions; increase heart rate, redistribute blood to muscles, raise blood sugar
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Adrenal cortex
HORMONE=Glucocorticoids (Cortisol)
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Steriods
2. Muscles, immune system, other tissues
3. Mediate response to stress; reduce metabolism of glucose; increase metabolism of proteins and fats; reduce inflammation and immune responses
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Adrenal cortex
HORMONE=mineralocorticoids
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Steriods
2. Kidneys
3. Stimulate excretion of potassium ions and reabsorption of sodium ions
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Stomach Lining
HORMONE=Gastrin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Stomach
3. Promotes digestion of food by stimulating release of digestive juices; stimulates stomach movements that mix food and digestive juices
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Lining of small intestine secretes:
HORMONE=secretin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Pancreas
3. Stimulate secretion of bicarbonate solution by ducts of pancreas
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Lining of small intestine
HORMONE=Cholecystokinin
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Peptide
2. Pancreas, liver, gallbladder
3. Stimulates secretion of digestive enzymes by pancreas and other digestive juices from liver; stimulates contractions of gallbladder and ducts
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Lining of small intestine
HORMONE=Enterogastrone
1. chemical nature
2. target(s)
3. Important properties or actions
```
1. Polypeptide
2. Stomach
3. Inhibits digestive activities in the stomach
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What feedback loops control hormone secretion?
negative feedback usually
- level of hormone in blood can exert feedback on glands responsible for its production
- internal conditions can exert feedback regulation on glands responsible for hormone production. hormone regulates particular internal condition and helps maintain homeostasis
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Releasing Factors from Hypothalamus (4)?
1. TRF
2. GnRF
3. CRF
4. GRF
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TRF
Thyrotropin-releasing factor
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GnRF
Gonadotropin-releasing factor
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CRF
Corticotropin-releasing factor
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GRF
Growth Hormone-releasing factor
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Why is hypothalamus master gland?
receives info about body/external-->sends tropic releasing hormones/release-inhibiting hormones (neurohormones) -->anterior pituitary via portal blood vessels -->neurons produce hormones
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neurohormones
tropic releasing hormones and release-inhibiting hormones
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What are the two things that the thyroid gland secretes?
1. Thyroxine
| 2. Triiodothyronine (T3)
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Thyroxine
increases metabolic rate and heart rate; promotes growth
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Calcitonin
decreases blood Ca2+
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How is the thyroid regulated?
by temp and day length
| feedback regulation by thyroxine concentration
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Goiter
if immune responds to thyrotropin receptor, thyroid will overproduce thyroxine, thyroid gland enlarges (low TSH)
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What happens if low on iodine?
thyroid gland enlarges (high TSH)
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Hypothyroidism (under)
Hashimoto, autoimmune destruction of follicles, low iodine diet, tired, cold intolerance, weight gain
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Hyperthyroidism (over)
Graves' disease, autoimmune attacking TSH receptor agonistic effect, nervousness, irritability, heart racing, weight loss, sleeplessness
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What does the medulla produce?
epinephrine and norepinephrine
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What does the cortex produce?
cortisol, mineralcorticoids, sex steriods
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Adrenal cortex
outer layer of adrenal gland
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What does the adrenal cortex produce?
produces steroid hormones from cholesterol
72
Adrenal medulla
core of the adrenal gland
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What does the adrenal medulla produce?
epinephrine and norepinephrine for use by the sympathetic nervous system in autonomic "fight or flight" responses
74
Epinephrine
released by adrenal medulla in response to fight-or-flight
75
Sex steroids
stimulate sexual development and reproductive activity (testosterone and estrogen) - secreted by testes and ovaries
76
steroid hormones
glucocorticoids, mineralcorticoids, sex hormones are produced by same biosynthetic pathway beginning with cholesterol
77
Glucocorticoids
influence blood glucose concentration and body metabolism
78
Cortisol
helps body respond to short-term stresses by increasing glucose supply for the brain and by suppressing the immune system
79
Mineral corticoids
influence ionic balance of extracellular fluids
80
Aldosterone
regulates salt concentration in the blood
81
Pancreas
below stomach, islets of langerhans cells produce insulin and glucagon
82
insulin
controls (lowers) blood glucose levels by stimulating cells to use glucose as fuel (glycolysis and cell respiration) and convert glucose into fat and glycogen
83
Glucagon
controls (raises) blood glucose levels by stimulating liver cells to break down glycogen into glucose
84
Somatostatin
released from pancreas in response to rapid rises in blood glucose and AA levels
85
What is the function of somatostatin?
extends nutrient absorption in gut and by cells themselves
86
Somatostatin - what effect on insulin and glucagon?
inhibits their release and slows digestive activity
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What gland produces calcitonin?
thyroid
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What produces parathyroid (PTH) hormone?
Parathyroid
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What controls the regulation of calcium levels in blood?
calcitonin, parathyroid hromone, vitamin D
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thyroid gland consists of:
two lobes on the side of the trachea
91
Parathyroid gland
our small structures embedded on the surface of the thyroid gland
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Thyroid produces two hormones
1. thyroxine
| 2. calcitonin
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Thyroxine (refer to slide 44)
elevates metabolic rate and carbohydrate use, part of the feedback loop
94
Calcitonin
excreted by thyroid and helps regulate (lower) blood calcium levels by decreasing activity of osteoclasts and increasing activity of osteoblasts
95
Parathormone
excreted by parathyroid and helps regulate (raise) blood calcium levels by increasing activity of the osteoclasts and increasing calcium uptake by the digestive system and kidneys
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Calcium distribution
99% in bones
1% in cells
0.1% extracellular fluids
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PTH helps regulate blood calcium by:
- deposition and absorption of bone
- excretion of calcium by the kidneys
- absorption of calcium from the digestive tract
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What organ does the hypothalamus regulate?
pituitary gland
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Median eminence
secrete releasing hormones from axon terminals in this
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portal system
hormones get released into this system of blood vessels to flood the anterior pituitary-->release tropic hormones that act on endocrine glands
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Hypothalamus have terminals in posterior pituitary where they release what 2 hormones?
1. Anti-diuretic hormone (ADH)
| 2. Oxytocin
102
Anti-diuretic hormone (ADH)`
acts on kidney to reabsorb water & inhabit formation of urine, thus increase blood pressure. it also constricts peripheral blood vessels (so it is also called vasopressin)
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Oxytocin
stimulates contraction of the uterus during childbirth and triggers milk letdown reflex during nursing. "love hormone"
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What are the hormones of the posterior pituitary?
neurohormones
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Where are neurohormones stored?
in nerve endings
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What hormones are secreted by the posterior pituitary?
oxytocin and vasopresin
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Growth hormone pathway
liver-->somatomedins
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Prolactin function
milk production, endocrine function of testes
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Endorphins and enkephalins are also called
natural opiates
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Anterior pituitary gland produces and secretes 4 tropic hormones, as well as direct hormones:
1. growth hormone
2. prolactin
3. melanocyte-stimulating hormone
4. endorphines/enkephalins
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Anterior Pituitary gland originates where?
originates as out pocketing of anterior end of embryonic digestive tract (mouth)
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What are the 2 hormones of the pituitary gland?
1. tropic hormones
| 2. direct hormones
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Tropic hormones
control activities of other endocrine glands
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Direct hormones
control activities directly
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What are the four Tropic hormones
1. Thyrotropin
2. Adrenocorticotropin (ACTH)
3. Luteinizing hormone (LH)
4. Follicle-Stimulating Hormone (FSH)
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Thyrotropin
stimulates thyroxin release by the thyroid glands
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Adrenocorticotropin (ACTH)
stimulates release of cortisol by the adrenal cortex
118
Luteinizing hormone (LH)
stimulates sex hormone secretion by the gonads
119
Follicle-stimulating hormone (FSH)
stimulates gamete maturation or production in ovaries and testes
120
What are the 4 direct hormones?
1. Growth hormone
2. Prolactin
3. Melanocyte-stimulating hormone (MSH)
4. Endorphins and enkephanlins
121
Growth hormone
stimulates cells to take up AAs for protein synthesis; promotes body growth by stimulating liver cells to produce somatomedins that stimulate bone and cartilage growth
122
Prolactin
helps in pregnancy and stimulates production and secretion of milk in females; helps control endocrine function of testes in males
123
Melanocyte-stimulating hormone
controls skin pigmentation
124
Endorphins/Enkephalins
help to control pain
125
How are adrenocorticotropin, MSH, endorphins and enkephalins produced?
cleavage (proteolysis) of large, parent polypeptide called propio-melanocortin
126
Water soluble hormones
don't cross membrane
| bind to integral membrane glycoprotein receptors, with catalytic activity on cytoplasm portion (ADH, insulin)
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What are 2 types of Water Soluble Hormones?
1. tyrosine and tryptophan (epinephrine/norepinephrine, thyroxine, melatonin)
2. peptide hormones (oxytocin, growth hormones, insulin)
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What do receptors activate?
protein kinases which phosphorylate other enzymes that become activated or inactivated
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What are the lipid soluble hormones?
steroid hormones
130
What are the steroid hormones?
ketones or alcohols: estradiol, testosterone, aldosterone, cortisol, cholesterol
131
What are the 3 regulations of hormone receptors?
1. normal signal
2. Agonists
3. Antagonists
132
Normal signal
target cell has a signal - cell is happy with that one signal
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Agonists
lead to increased signal and down-regulation
| -bind to the same receptor as neurotransmitter, elicit an effect that mimics that of the neurotransmitter
134
Antagonists
lead to decreased signal and up-regulation
- bind with receptor
- block neurotransmitter's response
135
What happens with endocrine cells?
secrete chemicals that can stimulate or inhibit cellular actions
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How do the chemicals from endocrine system induce their effects?
induce effects locally and systematically
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What kinds of effects of hormones can there be?
species, time, cell and receptor specific
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What hormones does the anterior pituitary produce?
FSH, LH, Thyrotropin, ACTH
139
What hormones does the Posterior Pituitary produce?
oxytocin (to uterus/breasts) and vasopressin (to kidney)
