Endocrine physiology and Anterior Pituitary Flashcards Preview

dmd 5248 > Endocrine physiology and Anterior Pituitary > Flashcards

Flashcards in Endocrine physiology and Anterior Pituitary Deck (63)
Loading flashcards...
1
Q

what major processes are under control of hormones

A

reproduction
growth and development
maintenance of homeostasis
regulation of metabolism

2
Q

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

A

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

3
Q

what do hormones actually do to target cells

A

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
Q

What are the three classes of hormones

A

amino acid derivatives
peptide hormones
lipid derivatives

5
Q

how do hormones travel in the blood

A

some freely, some bound to special carrier proteins

6
Q

thyroid hormones and catecholectamines are derivatives of what

A

the amino acid tyrosine

7
Q

Melatonin and seratonin are derivatives of what

A

the amino acid tryptophan

8
Q

What are the two types of peptide hormones

A

glycoproteins and short polypeptides and small proteins

9
Q

What is unique about the synthesis of peptide hormones

A

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
Q

what is the structure of glycoproteins

A

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

11
Q

which hormones are the three glycoproteins

A

TSH
FSH
LH

12
Q

which hormones are short chain peptides

A

ADH

OXT

13
Q

which hormones are small proteins

A

GH

PRL

14
Q

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

A

peptide hormones (small proteins/short polypeptides)

15
Q

What are the two types of lipid derived hormones

A

eiconasoids and steroid hormones

16
Q

what is the molecule from which eiconasoids are derived,

A

they are derived from arachadonic acid

17
Q

what are the main eiconasoids

A

leukotrienes
prostaglandins
thromboxanes
prostacyclins

18
Q

What are steroid hormones derived from

A

cholesterol

19
Q

which steroid hormones are secreted from where

A

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

20
Q

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

A

because they are bound to specific transport proteins

21
Q

how long do free hormones remain in circulation, and why

A

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
Q

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

A

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

23
Q

which type of receptor do lipid soluble hormones bind

A

intracellular proteins (because they can cross the plasma membrane)

24
Q

What are first messengers, and what do they do

A

they are often hormones, and they lead to second messengers

25
Q

what are important second messengers

A

cAMP
cGMP
Calcium ions

26
Q

what is amplification (hormones)

A

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
Q

What is down regulation with hormones

A

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

28
Q

what is up regulation with hormones

A

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

29
Q

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

A

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

30
Q

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

A

adenylate cyclase

31
Q

what does increased cAMP do in the cells

A

increase the metabolic activity (activates enzymes and opens channels)

32
Q

what does an activated G protein cause

A
  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
Q

what is the receptor cascade triggered by an activated G protein

A
  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
Q

how do steroid and thyroid hormones affect cells

A

they alter the rate of DNA transcription in the nucleus

35
Q

what are the functional counterparts of neural reflexes

A

endocrine reflexes

36
Q

what are most endocrine reflexes controlled by

A

negative feedback

37
Q

what are the three ways that endocrine reflexes can be triggered

A
  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
Q

what are the four types of hormone interactions

A

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
Q

how are hormone levels in the blood usually maintained

A

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

40
Q

what is the hypophysis

A

the pituitary gland

41
Q

where is the pituitary gland found

A

in the sella turcica

42
Q

what holds the pituitary gland in the sella turcica

A

the sellar diaphragm

43
Q

what connects the pituitary gland to the hypothalamus

A

the infundibulum

44
Q

how do the pituitary hormones act on target cells

A

via membrane receptors and cAMP as secondary messengers

45
Q

what is the adenophysis

A

the anterior pituitary

46
Q

what are the three regions of the anterior pituitary

A
pars distalis (main body)
pars tuberalis (top part)
Pars intermedia (part between ant. and post. pit)
47
Q

What are the anterior pituitary hormones

A
GH
TSH
ACTH
PRL
LH
FSH
48
Q

what are the posterior pituitary hormones

A

ADH

Oxytocin

49
Q

what is the hypophyseal portal system

A

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

50
Q

what is the median eminence

A

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

51
Q

what are portal systems

A

blook vessels that link two capillary networks

52
Q

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

A

releasing hormones and inhibiting hormones

53
Q

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

A

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
Q

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

A

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
Q

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

A

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

56
Q

what is cushing’s syndrome

A

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

57
Q

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

A

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

58
Q

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

A

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
Q

What is the function of GH (somatotropin)

A

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

60
Q

What affects GH levels

A

stress, sleep, exercise, blood glucose levels

61
Q

what are the problems associated with GH levels

A

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

62
Q

What usually causes acromegaly

A

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

63
Q

what causes gigantism

A

tumor in somatotropes in young kids or teenagers