Endocrine physiology and Anterior Pituitary Flashcards Preview

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Flashcards in Endocrine physiology and Anterior Pituitary Deck (63):
1

what major processes are under control of hormones

reproduction
growth and development
maintenance of homeostasis
regulation of metabolism

2

hormones make it to pretty much every cell in the body, why are only specific ones activated by specific hormones

because those specific cells have receptors specific to certain hormones. those are called TARGET CELLS

3

what do hormones actually do to target cells

they increase or decrease the rate of synthesis of enzymes or structural proteins, and/or they turn enzyme or membrane channels on or off.

4

What are the three classes of hormones

amino acid derivatives
peptide hormones
lipid derivatives

5

how do hormones travel in the blood

some freely, some bound to special carrier proteins

6

thyroid hormones and catecholectamines are derivatives of what

the amino acid tyrosine

7

Melatonin and seratonin are derivatives of what

the amino acid tryptophan

8

What are the two types of peptide hormones

glycoproteins and short polypeptides and small proteins

9

What is unique about the synthesis of peptide hormones

they are synthesized and pro-hormones. meaning they have no function or role until they are converted into active forms of the peptide hormone

10

what is the structure of glycoproteins

proteins of 200 or more amino acids that have a carb side chain

11

which hormones are the three glycoproteins

TSH
FSH
LH

12

which hormones are short chain peptides

ADH
OXT

13

which hormones are small proteins

GH
PRL

14

what type of hormones are all of the hormones secreted by the hypothalamus, heart, thymus, digestive tract, pancreas, and posterior lobe of the pituitary gland

peptide hormones (small proteins/short polypeptides)

15

What are the two types of lipid derived hormones

eiconasoids and steroid hormones

16

what is the molecule from which eiconasoids are derived,

they are derived from arachadonic acid

17

what are the main eiconasoids

leukotrienes
prostaglandins
thromboxanes
prostacyclins

18

What are steroid hormones derived from

cholesterol

19

which steroid hormones are secreted from where

androgens/estrogens/progestins are secreted by the gonads
corticosteroids are secreted by the adrenal cortex
calcitrol is secreted by the kidney

20

why do steroid hormones and thyroid hormones remain in circulation longer than other hormones

because they are bound to specific transport proteins

21

how long do free hormones remain in circulation, and why

less than an hour. because they are either used up, or broken down by the liver, and kidneys, or enzymes in the plasma and interstitial fluids

22

which types of proteins aren't lipid soluble, and why does that matter

catecholamines and peptide hormones, it matters because they can't cross plasma membranes of cells meaning they bind extracellular receptors

23

which type of receptor do lipid soluble hormones bind

intracellular proteins (because they can cross the plasma membrane)

24

What are first messengers, and what do they do

they are often hormones, and they lead to second messengers

25

what are important second messengers

cAMP
cGMP
Calcium ions

26

what is amplification (hormones)

the binding of a small number of hormones to membrane receptors leading to thousands of secondary messengers and magnification of the hormones effect on the target cell

27

What is down regulation with hormones

an increase in concentration of hormones leads to a decrease in number of hormone receptors (cells are less sensitive when hormones are high)

28

what is up regulation with hormones

the lower the concentration of hormones the higher the number of receptors. (cells are more sensitive when hormones are low)

29

what is the importance of G-proteins in the endocrine system

they are the link between first messengers (hormones) and second messengers

30

what is the enzyme that is activated when a hormone binds its receptor and then increases cAMP in the cell

adenylate cyclase

31

what does increased cAMP do in the cells

increase the metabolic activity (activates enzymes and opens channels)

32

what does an activated G protein cause

1. opening of calcium ion channels in the membrane
2. release of calcium from intracellular stores
3. activate phospholipase C (PLC)
4. triggers receptor cascade

33

what is the receptor cascade triggered by an activated G protein

1. DAG (diacylglycerol) and IP3 (inositol triphosphate) are produced
2. DAG and IP3 activate calcium ion channels through protein kinase C (PKC)
3. activation of calmodulin by calcium ions

34

how do steroid and thyroid hormones affect cells

they alter the rate of DNA transcription in the nucleus

35

what are the functional counterparts of neural reflexes

endocrine reflexes

36

what are most endocrine reflexes controlled by

negative feedback

37

what are the three ways that endocrine reflexes can be triggered

1. humoral stimuli (changes in composition of the extracellular fluid)
2. harmonial stimuli (arrival or removal of specific hormone)
3. neural stimuli (arrival of neurotransmitters at neuroglandular junctions)

38

what are the four types of hormone interactions

antagonistic (work against each other)
synergistic (enhance each others effects)
permissive (one hormone is required for the other to work)
integrative (hormone action differs with differing target tissues)

39

how are hormone levels in the blood usually maintained

negative feedback (when hormone levels are low, it causes more to be secreted, when there is enough, the hormone stops being secreted)

40

what is the hypophysis

the pituitary gland

41

where is the pituitary gland found

in the sella turcica

42

what holds the pituitary gland in the sella turcica

the sellar diaphragm

43

what connects the pituitary gland to the hypothalamus

the infundibulum

44

how do the pituitary hormones act on target cells

via membrane receptors and cAMP as secondary messengers

45

what is the adenophysis

the anterior pituitary

46

what are the three regions of the anterior pituitary

pars distalis (main body)
pars tuberalis (top part)
Pars intermedia (part between ant. and post. pit)

47

What are the anterior pituitary hormones

GH
TSH
ACTH
PRL
LH
FSH

48

what are the posterior pituitary hormones

ADH
Oxytocin

49

what is the hypophyseal portal system

the fenestrated capillary system that allows hypothalamic hormones to reach the anterior pituitary gland, and which gets hormones from the posterior pituitary gland

50

what is the median eminence

the swelling near the infundibulum where the hypothalamus releases its hormones into the interstitial fluids

51

what are portal systems

blook vessels that link two capillary networks

52

what are the two types of hormones released by the hypothalamus to the hypophyseal portal system

releasing hormones and inhibiting hormones

53

what is the function of FSH, what are problems with incorrect FSH levels

regulation of maturation of follicular cells, and production of estrogen in women.
regulation of maturation of spermatocytes in men
problems with FSH levels can lead to irregular menstrual cycles, infertility and impotence

54

what is the function of LH, and what are the problems with incorrect LH levels

regulation of ovulation and production of progesterone in women
regulation of production of testosterone
problems with LH levels can cause irregular menstrual cycles, amenorrhea, and impotence

55

What is the function of ACTH, and what are the problems with low ACTH levels

stimulation of the adrenal cortex to produce and secrete corticosteroids. when we don't have ACTH we become stressed out

56

what is cushing's syndrome

when the body is exposed to cortisol for long periods of time. leads to fat gain, muscle loss, anxiety

57

What is the function of TSH, and what are problems associated with incorrect TSH levels

it regulates the release of thyroid hormones from the thyroid. it can cause loss of the optic nerve

58

What is the function of PRL, and what are the problems associated with incorrect PRL levels

it females it regulates mammary gland growth, and breast milk production.
in males it influences interstitial cell's sensitivity
wrong levels can lead to too low or too high breastmilk production, and can lead to fertility problems

59

What is the function of GH (somatotropin)

it stimulates growth and cell division, and stimulates the liver to secrete somatomedin

60

What affects GH levels

stress, sleep, exercise, blood glucose levels

61

what are the problems associated with GH levels

deficiency = dwarfism
too much whole life = gigantism
to much later in life = acromegaly

62

What usually causes acromegaly

tumor of the pituitary gland or tumor of the pancreas, lung, or adrenal gland

63

what causes gigantism

tumor in somatotropes in young kids or teenagers