gritti 16

Question 1

what’s the main difference between endocrine and exocrine glands?

Answer 1

no ducts are present in endocrine glands.
hormones are released into the blood stream directly.

Question 2

autocrine signaling

Answer 2

the hormones will act on the same cell that has released them

Question 3

Juxtacrine signaling

Answer 3

happens by cell to cell contact
a cell to receive the signal has to be in direct contact with the cell that has produced the signaling molecule (the molecule remains attached to the cell’s surface)

Question 4

paracrine signaling

Answer 4

the hormones act on short distances (neighboring cells) but not cell to cell direct contact

Question 5

classical endocrine signaling

Answer 5

the hormones are released into the blood stream and they reach organs that are far from hormones releasing cells

Question 6

endocrine cells are from which origin?

Answer 6

epithelial origin

Question 7

what do steroid hormones derive from?

Answer 7

cholesterol

Question 8

what is the rate limiting step in steroid hormones synthesis?

Answer 8

pregnenolone

Question 9

serotonin and melatonin derive from which amino acid?

Answer 9

tryptophan

Question 10

histamine derive from which amino acid?

Answer 10

histidine

Question 11

eicosanoids are hormones derived from?

Answer 11

-fatty acids
-in particular from arachidonic acid (except some exceptions)

Question 12

prostaglandins are hormones derived from?

Answer 12

a fatty acids-derived type of hormones

Question 13

each pancreatic islet is composed of

Answer 13

alpha cells->glucagon
located peripherally
beta cells->insulin
located centrally
delta cells->somatostatin
scattered, less abundant
these cells can not be distinguished in an H and E staining

Question 14

parasympathetic and sympathetic fibers within an islet of langheran

Answer 14

sympathetic
stimulate glucagon release
parasympathetic
stimulate both glucagon and insulin release

Question 15

enterochromaffin cells

Answer 15

present in both the islets and in ducts in the pancreas.
primary source of serotonin which participates in the overall regulation of the endocrine function of this organ

Question 16

pituitary gland

Answer 16

-at the base of the brain
-divided in
1. neurohypophysis (derives from nervous system) and is connected to the hypothalamus by the infudibular stalk

2. adenohypophysis (derives from the oral ectoderm, upgrowth invagination of the primitive oral cavity)

histologically you can tell that they have different embryological origins

Question 17

neurohypophysis and adenohypohphis are divided in different pars:

Answer 17

neurohypophysis
pars nervosa

adenohypophysis
pars distalis (bigger one)
pars tuberalis (wraps around the infundibulum)
pars intermedia (boundary between Adeno and neuro hypophysis)

Question 18

hypothalamic hypophyseal tract, what is it?

Answer 18

a vessel system that covers the neurohypophysis
take up all the peptides and hormones produced in the posterior pituitary and bring them to the target organs through circulation

Question 19

hypothalamic hypophysisal portal system, what is it?

Answer 19

2 different group of vessels that come from the carotid artery.
one covers the infundibular stalk
the other one takes up the hormones produced in the adenohypophysis and bring them to the target organs through circulation

Question 20

which types of cells can I find in the adenohypophysis?

LEARN THEM

Answer 20

chromophobes
do not secrete hormones
-pailed stained
chromophils
hormones secreting cells
-acidophils
stained in pink
1. somatotrophin cells that produce somatotrophin (growth hormones that act on bones and on the liver) lactotrophic cells that produce prolactin that acts on the mammary glands
-basophils
stained in blue/purple
-corticotropic cells that produce adrenocorticotropic hormone that act on the adrenal cortex
-gonadotropic cells that produce sex hormones (FSH, LH)
-thyrotropic cells that produce thyroid stimulating hormone that act on the thyroid gland

Question 21

what is the peculiarity of the pars intermedia in the adenohypophisis?

Answer 21

the presence of protein-filled cysts

Question 22

somatostatin released in the hypothalamus inhibits the production of?

Answer 22

TSH and somatotropin

Question 23

dopamine released in the hypothalamus inhibits the release of?

Answer 23

prolactin

Question 24

neurohypophisis cell composition

Answer 24

non myelinated axons that come from neurons with the cell body in the hypothalamus.
NB: HORMONES- SECRETING NEURONS
around the axons there are pituicytes cells as structural support

Question 25

hormones secreted by the posterior pituitary

Answer 25

antidiuretic hormones (act on the kidney) oxytocin (act on the uterus)

Question 26

are hormones released from the neurons in the posterior pituitary free?

Answer 26

no, they are bonded to proteins called neurophysin I and II

Question 27

herring bodies of the posterior pituitary

Answer 27

enlargement of the axons where hormones accumulate

Question 28

hormone neurophysin complex

Answer 28

hormones when released by the hormones releasing neurons in the posterior pituitary are bonded to neurophysin 1 and 2

Question 29

adrenal glands

Answer 29

on top of the kidneys covered by a connective capsule inner part: medulla comes from the neural crest outer part:cortex comes from the mesoderm

Question 30

the cortex is divided in three

Answer 30

zona glomerulosa zona fascicolata zona reticularis

Question 31

which hormones are produced in the medulla of adrenal glands?

Answer 31

peptide hormones (somatostatin and substance P) catecholamines (adrenaline and noradrenaline)

Question 32

which hormones are produced in the cortex of adrenal glands?

Answer 32

production of steroid hormones glucocorticoids, mineralocorticoids and androgens

Question 33

zona glomerulosa of the cortex of the adrenal gland

Answer 33

-on the outside -closely packed columnar cells with many vessels -cells organized in glomeruli -produce mineralocorticoids (aldosterone-osmotic balance in the kidney and corticosterone-stress hormone)

Question 34

zona fascicolata of the cortex of adrenal glands

Answer 34

-cells organized in chords -similar appereance as the zona glomerulosa -secretion of glucocorticoids (cortisol) important for carbs, protein and lipid intake

Question 35

zona reticularis

Answer 35

-closest one to the medulla -irregular appearance with lots of capillaries -cells store lipids droplets -secrete androgens

Question 36

what's the name of the cells in the adrenal medulla?

Answer 36

chromaffin cells that arrange in clusters around medullary veins secrete catecholamines (adrenaline and noradrenaline->80% adrenaline, more abundant production) -these cells are modified postganglionic neurons -when acetylcholine binds to specific receptors, catecholamines are released

Question 37

chromogranins

Answer 37

proteins bonded to catecholamines (that are stored in granules)

Question 38

thyroid gland secretes

Answer 38

-tri-iodotyronine(T3) -thyroxine (T4) regulate the basal metabolic rate. the secretion of these two hormones is regulated by the pituitary TSH-thyroid stimulating hormone -calcitonin (regulates blood calcium level->secretion of it make calcium level to drop->the secretion is dependent to blood calcium level)

Question 39

thyroid follicles

Answer 39

-where hormones are stored in the thyroid -thyrocytes are the epithelial cells around the follicle: simple cuboidal epithelium -colloid is present inside the follicle with a glycoprotein called thyroglobulin (precursor for active thyroid hormones) -around the follicles there is reticular connective tissue with fenestrated capillaries to favor the entrance of hormones into the bloodstream

Question 40

what's the name of the cells in the thyroid that secrete calcitonin?

Answer 40

parafollicular cells around the thyroid follicle

Question 41

which cells secrete melatonin?

Answer 41

pinealocytes in pineal gland

Question 42

corpora arenacea in pineal gland

Answer 42

concentration of mineralized salts and calcium in the parenchyma

Question 43

cells present in the parathyroid gland

Answer 43

-oxyphil cells (derivatives of principal cells, appear with an eosinophilic cytoplasm) -principal cells (granules with stored parathyroid hormone->regulates calcium blood level)

Question 44

PTH and CALCITONIN: effects

Answer 44

PTH->increase blood calcium levels when released calcitonin->decrease calcium levels when released