Lecture 36: Endocrine Flashcards Preview

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Flashcards in Lecture 36: Endocrine Deck (49):
1

difference in formation of endocrine vs exocrine glands

both invaginate into the connective tissue but exocrine remains in a duct that secretes into the lumen, endocrine is separated and duct cells dissapear

2

two types of endocrine cells

cord/cluster and follicle (these are both surrounded by capillaries)

3

hormones

chemical substances synthesized by endocrine cells and secreted

4

where do hormones get secreted

into bloodstream(distant target cells), into tissue space (adjacent or nearby target cells), onto own cell surface (own target cells)

5

three signaling mechanisms

1. endocrine
2. paracrine
3. autocrine

6

endocrine signaling

secreted into the blood

7

paracrine signaling

secreted into extracellular space (eg somatostatin inhibits insulin secretion in islets of langerhan)

8

autocrine secretion

secreted on own cell surface (eg insulin, TGF beta)

9

what are the three types of hormones chemically speaking

1. peptides and glycoproteins (pit hormones, parathyroid, islets of langerhan and GI tract)
2. steroids (hormones of adrenal cortex, ovary and testis)
3. amino acids (tyrosine) eg hormones of thyroid and adrenal medulla

10

on an EM what is noticeable about peptide/glycoprotein hormones

contain granules which store the hormones

11

steroid hormone producing cells on EM

hormones not stored in cells

12

Endocrine glands whose sole functions are hormone production

PPPAT
Pituitary
Pineal
Thyroid
Parathyroid
Adrenal

13

endocrine tissues found in association with organs which have other functions

pancrease, ovary, testis, kidney, liver

14

diffuse endocrine system

single hormone producing cells diffusely scatted in the digestive and respiratory systems

15

where is the pituitary located

beneath the floor of the third ventricle, connected to the hypothalamus

16

other word for pituitary

hypophysis

17

where does the pituitary lie

in the hypophyseal fossa, a bony depression of the sella turcia of the sphenoid bone

18

other word for anterior pituitary

adenohypophysis / pars distalis

19

parts of anterior pituitary

pars tuberalis
pars intermedia

20

parts of posterior pituitary

infundibulum (pituitary stalk) and median eminence (hypothalamus)

21

other word for posterior pituitary

neurohypophysis / pars nervosa

22

where do the neurohypophysis (posterior pit) and adenohypohysis (anterior pit) originate from

neuro = nervous tissue of the hypothalamus
adeno = ectoderm of the roof of the mouth
*DIFFERENT EMBRYO SOURCES*

23

how many hormones and cell types in the pituitary

6 hormones
1) GH
2) Prolactin
3) Corticotropin (ACTH)
4) FSH
5) LH
6)Thyrotropin (TSH)

5 cell types because FSH and LH are from the same cell type

24

where are anterior pituitary hormones stored

in the granules

25

endocrine cell types of anterior pituitary/pars distalis

Acidophils
1. Somatotrophs (50%) GH
2. Mammotrophs (20%) prolactin
Basophiles
3. Corticotrophs (20%) Corticotropin (ACTH)
4. Thyrotrophs (5%) Thyrotropin (TSH)
5. Gonadotrophs (5%) FSH and LH
Chromophobes: degranulated acidophils or basophils

26

FSH and LH target

the ovary and testis

27

ACTH target

adrenal cortex

28

GH target

skeleton (bone growth), adipose tissue, and muscle

29

Prolactin target

mammary gland

30

what is secretion in the pars distalis/ant pit controlled by

hypothalamic releasing or inhibiting hormones

31

what controls hypothalamic releasing or inhibiting hormones

hypophyseal (pituitary) portal system which provides anatomical-functional link between hypothalamus and pars distalis of ant pit

32

what is the blood supply to the pituitary

hypophyseal portal system

33

map of control of pars distalis

1. hypothalamus releases neurosecretory cells (neurons) with releasing or inhibiting hormones
2. these go through the hypophyseal portal system and act on ant pit hormones
3. these then act on target organs

34

hypothalamic hormones and their function

1. GH releasing hormone
2. Corticotropin releasing hormone
3. TSH releasing hormone
4. Gonadotropin releasing hormon
5. Dopamine (inhibits prolactin release)
6. Somatostatin (inhibits GH release)

35

where is the pars intermedia

in between ant pit and post pit

36

what does pars intermedia release

2 types of MSH (melanocyte stimulating)
1. beta MSH for skin pigmentation 2. alpha msh for anti appetite

37

what are MSHs a product of

pro-opiomelanocortin (POMC)

38

what are the cells (granules) of the pars intermedia similar to

those of corticotrophs which secrete ACTH

39

what do cells/granules of pars intermedia and corticotrophs synthesize

pro-opiomelanocortin which splits into
1. ACTH (lipotropins for lipid metabolism) 2. Endorphines (endogenous opioids)
3. MSHs (beta and alpha) for skin pigmentation and anti appetite

40

hormones secreted by pars nervosa of of post pit

Antidiuretic hormone (ADH, vasopressin) and oxytocin

41

what are ADH and oxytocin bound by and where are they released from

a carrier protein and secreted by pars nervosa of post pit

42

herring bodies

sites of accumulation of hormones combined with neurophysin in the terminal portion of an axon

43

what controls hormone release in herring bodies

nerve impulses passing down axons from hypothalamus

44

what is the pineal gland

diverticulum of posterior diencephalon and located at posterior end of third ventricle

45

corpora arenacea

extracellular calcified bodies containing CaPO4 and MgPO4 and carbonate in an organic matrix. INCREASE WITH AGE!

46

what secretes melatonin

pinealocytes

47

what regulates synthesis of melatonin

incuded by darkness and supressed by light, thought to regulate diurnal rythyms of body

48

what is melatonin synthesized from

amino acid tryptophan via serotonin

49

side effect of melatonin

antireproductive effects because decreases gonadotropin release