Physiology Chapter 7

Front 1

hormones act on their target cells in 3 ways

Back 1

controlling the rates of enzymatic reactions
-controlling the transport of ions/molecules across cell membranes
-controlling gene expression and synthesis of proteins

Front 2

goiter

Back 2

enlarged thyroid gland where dietary iodine is needed

Front 3

classic hormones and techniques

Back 3

1) remove suspected gland
2) either place the gland back in or administer an extract
3) implant the gland in a normal animal
4) purify extracts of the gland to isolate the active substance

Front 4

classic hormones include

Back 4

hormones of
pancreas
thyroid
adrenal glands
pituitary
gonads

Front 5

hormones are secreted by

Back 5

classic endocrine glands
isolated endocrine cells (hormones of the diffuse endocrine system)
-neurons (neurohormones)
-cells of the immune system (cytokines)

Front 6

secretion

Back 6

movement of a substance from the intracellular compartment to the extracellular comp. or external environment

Front 7

ectohormone

Back 7

signal molecules secreted into the external environment

Front 8

pheromones

Back 8

specialized ectohormones that act on other organisms of the same species to elicit a physiological response
-sex pheromones or sea anemones secrete alarm pheromones

Front 9

hormones exert their effect at very ____ concentrations

Back 9

low concentrations

Front 10

why are cytokines not considered hormones?

Back 10

peptide cytokines are synthesized and released on demand
-classic peptide hormones are made in advance and stored in the parent endocrine cell

Front 11

hormones act by?

Back 11

binding to target cell receptors and initiating biochemical responses known as cellular mechanism of action of the hormone

Front 12

the variable responsiveness of a cell to a hormone depends primarly on

Back 12

cell's receptor
signal transduction pathways

Front 13

insulin and blood glucose concentration

Back 13

blood glucose conc. increases after a meal and insulin is needed for glucose to leave blood and enter cells
-too much insulin will result in too low of bgc
-thus we need to limit insulin secretion

Front 14

hormone's half-life

Back 14

rate of hormone breakdown
-hormones in bloodstream are degraded into inactive metabolites by enzymes found primarily in the liver and kidneys

Front 15

hormones are divided into 3 different main chemical classes

Back 15

peptide/protein hormones
steroid hormones
amine hormones

Front 16

peptide/protein hormones

Back 16

composed of linked amino acids

Front 17

steroid hormones

Back 17

derived from cholesterol

Front 18

amine hormones

Back 18

derived from one of two amino acids: tryptophan or tyrosine

Front 19

most hormones are what kind?

Back 19

peptides or proteins

Front 20

peptide hormones
synthesis and storage

Back 20

made in advance
stored in secretory vesicles

Front 21

Pep
release from parent cell

Back 21

exocytosis

Front 22

pep
transport in blood

Back 22

dissolved in plasma

Front 23

pep
half-life

Back 23

short

Front 24

pep
location of receptor

Back 24

cell membrane

Front 25

pep
response to receptor-ligand binding

Back 25

activation of 2nd messenger systems; may activate genes

Front 26

pep
general target response

Back 26

modification of existing proteins and induction of new protein synthesis

Front 27

pep
examples

Back 27

insulin
parathyroid hormone

Front 28

steroid hormones
synthesis and storage

Back 28

synthesized on demand from precursors

Front 29

steroid
release from parent cell

Back 29

simple diffusion

Front 30

steroid
transport in blood

Back 30

bound to carrier proteins

Front 31

steroid
half-life

Back 31

long

Front 32

steroid
location of receptor

Back 32

cytoplasm or nucleus; some have membrane receptors also

Front 33

steroid
response to receptor-ligand binding

Back 33

activation of genes for transcription and translation

Front 34

steroid
general target response

Back 34

induction of new protein synthesis

Front 35

steroid
examples

Back 35

estrogen, androgens, cortisol

Front 36

amines
catecholamines
syn and storage

Back 36

made in advance; stored in secretory vesicles

Front 37

cate
release from parent cell

Back 37

exocytosis

Front 38

cate
transport in blood

Back 38

dissolved in plasma

Front 39

cate
half-life

Back 39

short

Front 40

cate
location of receptor

Back 40

cell membrane

Front 41

cate
response to receptor-ligand binding

Back 41

activation of second messenger systems

Front 42

cate
general target response

Back 42

modification of existing proteins

Front 43

cate
examples

Back 43

epinephrine
norepinephrine

Front 44

amines
thyroid hormones
syn and storage

Back 44

made in advance, precursor stored in secretory vesicles

Front 45

thyroid
release from parent cell

Back 45

simple diffusion

Front 46

thyroid
transport in blood

Back 46

bound to carrier proteins

Front 47

thyroid
half-life

Back 47

long

Front 48

thyroid
location of receptor

Back 48

nucleus

Front 49

thyroid
response to receptor-ligand binding

Back 49

activation of genes for transcription and translation

Front 50

thyroid
general target response

Back 50

induction of new protein synthesis

Front 51

thyroid
examples

Back 51

thyroxine

Front 52

peptide hormones
initial

Back 52

comes off ribosome
a large inactive protein known as a preprohormone which contains one or more copies of a peptide hormone, a signal sequence that directs the protein into the lumen and other peptide sequences

Front 53

peptide hormone
moves thru ER and Golgi then

Back 53

signal sequence is removed, creating a smaller but still inactive prohormone which is packed with proteolytic enzymes that chop the prohormone into active hormone (this is called post-translational modification)

Front 54

co-secretion

Back 54

peptide fragments are created from prohormone are released together into the ecf

Front 55

why do peptide hormones dissolve so easily?

Back 55

because they are water soluble

Front 56

peptide hormones are usually unable to enter the target cell, why?

Back 56

they are lipophobic

Front 57

where are steroids made?

Back 57

adrenal cortex; the outer portion of the adrenal glands

Front 58

steroids are lipo___ and have __ amounts of SER

Back 58

philic and a lot of SER

Front 59

why are steroid hormone molecules bound to protein carrier molecules?

Back 59

because they are not very soluble in plasma and other bodily fluids

Front 60

steroid hormones bound to protein carriers does what to half-life and entry to target cells

Back 60

extends half-life but blocks entry to target cells

Front 61

carrier proteins are lipo___ and ___ through the membrane

Back 61

phobic and cannot diffuse

Front 62

the peptide chain of insulin's prohormone does that

Back 62

folds back on itself with the help of disulfide bonds (S-S) and cleaves into insulin and C-peptide

Front 63

peptide hormones ___ target cells and

Back 63

cannot enter their target cells and must combine with membrane receptors that initiate signal transduction processes.

Front 64

genomic effect

Back 64

when any hormone alters gene activity on the target cell

Front 65

steroid hormones

Back 65

adrenal cortex: aldosterone and cortisol
ovary: estradiol

Front 66

steroid hormone receptors are typically in the ...

Back 66

cytoplasm or nucleus

Front 67

the receptor-hormone complex binds to DNA

Back 67

and activates or represses one or more genes

Front 68

the amine hormone melatonin is derived

Back 68

from tryptophan

Front 69

all the other amine hormones- catecholamines (1) and thyroid (2)hormones- are derived from

Back 69

tyrosine

Front 70

catecholamines are

Back 70

(epinephrine, norepinephrine, and dopamine) are neurohormones that bind to cell membrane receptors the way peptide hormones do

Front 71

thyroid hormones

Back 71

behave more like steroid hormones, with intracellular receptors that activate genes

Front 72

hormones can be classified by their

Back 72

reflex pathways

Front 73

a resultant decrease in blood glucose concentration acts as a

Back 73

negative feedback signal and turns off the reflex, ending release of insulin

Front 74

in the simplest endocrine reflexes

Back 74

endocrine cell acts as both sensor (receptor) and integrating center
examples: parathyroid hormone (PTH), insulin, and glucagon

Front 75

parathyroid endocrine cells

Back 75

clustered into 4 small glands and they monitor plasma ca2+ concentration with aid of G protein-coupled calcium receptors
-when plasma ca2+ concentration falls below a certain level and fewer receptors are bound to calcium, inhibition ceases and parathyroid cells secrete PTH.

Front 76

the increase in plasma calcium is a ___ that

Back 76

a negative feedback signal that turns off the reflex, ending the release of parathyroid hormone

Front 77

neurohormones are secreted into the blood by

Back 77

neurons

Front 78

what are the 3 major groups of neurohormones?

Back 78

catecholamines made by modified neurons in the adrenal medulla
-hypothalamic secreted from the posterior pituitary
-hypothalamic nh that control hormone release from the anterior pituitary

Front 79

the pituitary gland

Back 79

two fused glands
-anterior gland
-posterior gland

Front 80

anterior pituitary

Back 80

true endocrine gland of epithelial origin
hormones are adenohypophyseal secretions

Front 81

posterior pituitary

Back 81

extension of neural tissue of the brain
-secretes neurohormones made in the hypothalamus

Front 82

infundibulum

Back 82

the stalk that connects the pituitary to the brain

Front 83

posterior pituitary does what for which?

Back 83

is the storage and release site for 2 nh: oxytocin and vasopressin
-these are hypothalamic neurohormones

Front 84

vasopressin

Back 84

antidiuretic hormone
-regulates water balance in the body
-has 9 amino acids

Front 85

oxytocin

Back 85

controls the ejection of milk during breast-feeding and contractions of uterus

Front 86

synthesis, storage, and release of pp h

Back 86

hormone is made and packaged in cell body of neuron
-vesicles are transported down the cell
-vesicles containing hormone are stored in pp
-hormones are released into blood

Front 87

anterior pituitary

Back 87

major endocrine gland that secretes six physiologically significant hormones and is controlled by hypo nh

Front 88

the 6 hormones are

Back 88

prolactin
thyrotropin
adrenocorticotropin
growth hormone
follicle-stimulating hormone
luteinizing hormone

Front 89

trophic hormone

Back 89

controls the secretion of another hormone

Front 90

anterior pituitary is a complex reflex

Back 90

3 integrating centers
-hypothalamus
-anterior pituitary
-endocrine target of the pituitary hormone
instead of the response acting as the negative feedback signal, the hormones themselves are the signals

Front 91

long-loop negative feedback

Back 91

cortisol secreted from the adrenal cortex feeds back to suppress secretion of the trophic hormones

Front 92

short-loop negative feedback

Back 92

pituitary hormones feed back to decrease hormone secretion by the hypothalamus

Front 93

which hormones have an advantage?

Back 93

those that are secreted into a portal system over the general circulation because with a ps, a much smaller amount of hormone can be secreted to elicit a given level of response.

Front 94

endocrine release their hormones into

Back 94

the second set of capillaries for distribution to the rest of the body

Front 95

what do portal vessels do?

Back 95

carry trophic hormones directly to the ap

Front 96

anterior pituitary hormone controls

Back 96

growth, metabolism, and reproduction
-often called the master gland of the body

Front 97

prolactin controls

Back 97

milk production in females
-in both sexes, appears to play a role in regulation of the immune system

Front 98

growth hormone

Back 98

also called somatotropin
-affects metabolism of many tissues in addition to stimulating hormone production by the liver

Front 99

prolactin and growth hormone are the only 2 anterior pituitary hormones whose secretion is

Back 99

controlled by both releasing hormones and inhibiting hormones

Front 100

gonadotropins

Back 100

follicle-stimulating hormone
luteinizing hormone

Front 101

thyroid-stimulating hormone

Back 101

controls hormone synthesis and secretion in the thyroid gland

Front 102

ACTH

Back 102

acts on certain cells of the adrenal cortex to control synthesis and release of steroid hormone cortisol

Front 103

3 types of hormone interaction

Back 103

synergism
permissiveness
antagonism

Front 104

synergism

Back 104

glucagon from the pancreas is the hormone primarily responsible for elevating blood glucose levels
but so does cortisol and epinephrine
-effet of interacting hormones is more than additive

Front 105

permissive hormone

Back 105

allows another hormone to exert its full effect
-1 hormone cannot fully exert its effects unless a second hormone is present

Front 106

what two hormones work best for normal development of reproductive system?

Back 106

reproductive hormones with adequate thyroid hormone

Front 107

antagonistic hormones have

Back 107

opposing effects
-glucagon and growth hormone raise blood glucose conc. while insulin lowers it

Front 108

3 basic patterns of endocrine pathology

Back 108

hormone excess
hormone deficiency
abnormal responsiveness of target tissues to a hormone

Front 109

hypersecretion exaggerates a hormone's effects

Back 109

caused by benign tumors and cancerous tumors of the endocrine glands

Front 110

secondary hypersecretion due to hypothalamic problem

Back 110

hypothalamus
increased CRH
increased ACTH
increased cortisol
negative feedback fails
symptoms of excess
very rare

Front 111

secondary hypersecretion due to pituitary problem

Back 111

anterior pituitary
decrease in CRH
increase in ACTH
increase in cortisol
negative feedback blocks CRH
most common 2/3 of cases

Front 112

primary hypersecretion due to problem with adrenal cortex

Back 112

adrenal cortex
decrease in CRH
decrease in ACTH
increase in cortisol
negative feedback on both CRH and ACTH

Front 113

diabetes is what

Back 113

an endocrine disorder characterized by the presence of glucose in the urine

Front 114

what is the most important function of the kidney?

Back 114

the homeostatic regulation of water and ion content of the blood
-also called salt and water balance or fluid and electrolyte balance
-waste removal is important

Front 115

kidney function can be divided into 6 areas

Back 115

regulation of ecf volume and bp
-regulation of osmolarity
-maintenance of ion balance
-homeostatic regulation of pH
-excretion of wastes
-production of hormones

Front 116

regulation of ecf volume and blood pressure

Back 116

when ecf volume decreases, bp also decreases which is not good thing for maintaining adequate blood flow to the brain

Front 117

regulation of osmolarity

Back 117

body integrates kidney function with behavioral drives to maintain blood osmolarity at a value close to 290 mOsM

Front 118

maintenance of ion balance

Back 118

sodium is the major ion involved in the regulation of ecf volume and osmolarity
K+ and calcium are also closely regulated

Front 119

homeostatic regulation of pH

Back 119

kidneys play a huge role in correcting pH disturbances but not as fast as the lungs
-if ecf becomes too acidic, kidneys remove H+ and conserve bicarbonate ions

Front 120

excretion of wastes

Back 120

a metabolite of hemoglobin called urobilinogen gives urine its characteristic yellow color

Front 121

production of hormones

Back 121

kidney cells synthesize erythropoietin which regulates rbc synthesis
-release renin, an enzyme that regulates the production of hormones involved in sodium balance and bp homeostasis
-renal enzymes help convert vitamin d into a hormone that regulates calcium balance

Front 122

do the kidneys have a reserve capacity?

Back 122

kidneys have a huge rc
you must lose nearly 3/4 of your kidney before homeostasis begins to be affected