Endocrine System

Question 1

how can we categorize endocrine organs

Answer 1

into 2 types: primary organs/glands and secondary organs

Question 2

what are the secondary endocrine organs

Answer 2

heart, stomach, kidney, liver, skin, small intestine

Question 3

what are the primary endocrine structures

Answer 3

hypothalamus; pituitary, pineal, thyroid, parathyroid, adrenal glands, thymus, pancreas, gonads

Question 4

what is the anterior lobe derived from

Answer 4

epithelial tissue

Question 5

what is the posterior lobe derived from

Answer 5

neural tissue

Question 6

describe the neural connection b/w hypothalamus and posterior pituitary gland

Answer 6

posterior lobe has neural tissue with axon terminals of neurons that originate in the hypothalamus

Question 7

what do the neural endings in the posterior tube secrete

Answer 7

neurohormones (peptide hormones)

Question 8

provide examples of neural endings in the posterior lobe that secrete neurohormones

Answer 8

• supraoptic nuclei secrete oxytocin
• paraventricular nuclei secrete ADH (antidiuretic hormone)

Question 9

describe the neurosecretory reflex

Answer 9

neurons release hormones using exocytosis when they receive a signal

Question 10

what is the function of ADH

Answer 10

• stands for antidiuretic hormone but also called vasopressin
• responsible for water balance and osmolarity (target cells in kidney)
• release stimulated by increase in plasma solute concentration

Question 11

what is the function of oxytocin

Answer 11

• responsible for uterine contractions and milk release (target cells in uterus and breasts)
• release stimulated by pressure in uterus and sucking from baby

Question 12

what are tropic hormones; how can they be classfied

Answer 12

• hormones that regulate secretion of other hormones
• stimulating, inhibiting

Question 13

draw the signalling pathway flow of tropic hormones in hypothalamus

Answer 13

• hypothalamus release tropic hormone
• second tropic hormone released from anterior pituitary gland
• third hormone released from another endocrine gland
• target cells respond

Question 14

describe the importance of the hypothalamic-pituitary portal system

Answer 14

• provides direct delivery of tropic hormones to target cell in anterior pituitary
• lets tropic hormones to remain more concentrated which has a greater effect on hormone release

Question 15

draw out the feedback loops that regulate multistep pathways of hormone release

Answer 15

….

Question 16

draw out the regulation of cortisol release, label the tropic hormone(s) and explain why this is long loop negative feedback

Answer 16

….

Question 17

describe the pineal gland

Answer 17

• glandular tissue in brain
• secretes melatonin

Question 18

what is the importance of melatonin

Answer 18

• circadian rhythms (maybe)
• timing of seasonal processes in mammals

Question 19

what are the hormones in the thyroid gland and what do they do

Answer 19

• tetraiodothyronine (T4)
• triiodothyronine (T3)
• regulate metabolism
• calcitonin
• regulates calcium levels in blood

Question 20

what hormone is released by the parathyroid glands and what does it do

Answer 20

• parathyroid hormone (PTH)
• regulates calcium levels in blood by acting on bones, kidneys, intestines to increase blood calcium

Question 21

what hormone is released by the thymus gland and what does it do

Answer 21

• thymosin
• important for immunity
• maturation of T lymphocytes

Question 22

what are the layers of the adrenal glands top to bottom

Answer 22

capsule, zona glomerulosa, zone fasciculuta, zona reticularis, adrenal medulla

Question 23

what is an adrenocorticoid

Answer 23

• hormones secreted collectively from adrenal cortex
• all are steroid hormones
• different types

Question 24

what are three types of adrenocorticoids

Answer 24

• mineralocorticoids (aldosterone)
• glucocorticoids (cortisol)
• sex hormones (androgens)

Question 25

where are mineralocorticoids secreted from and what do they do

Answer 25

- zona glomerulosa - regulates sodium and potassium levels

Question 26

where are glucocorticoids secreted from and what do they do

Answer 26

- zona fasciculata and reticularis - regulates body's response to stress and also regulates metabolism

Question 27

where are sex hormones released from

Answer 27

- zona fasciculata and reticularis - regulate reproductive function

Question 28

describe the adrenal medulla

Answer 28

- contains chromaffin cells - secretes catecholamines (80% epinephrine; 20% norepinephrine; less than 1% dopamine) - neurally controlled

Question 29

what are the components of the exocrine pancreas

Answer 29

- acinar cells - duct cells

Question 30

what are the components of the endocrine pancreas

Answer 30

- exocrine pancreas layer (islets of Langerhans make up whole) - alpha cell (glucagon) - beta cells (insulin) - delta cell (somatostatin) - F cell (pancreatic polypeptide)

Question 31

describe the gonads

Answer 31

- ovaries and testes - have endocrine and nonendocrine functions

Question 32

describe endocrine functions of the gonads

Answer 32

- male: secreting androgens, testosterone, androstenedione - female: estrodiol, progesterone

Question 33

describe nonendocrine functions of the gonads

Answer 33

ova and sperm production

Question 34

what does the concentration of free hormone in blood depend on

Answer 34

- rate of hormone secretion - amount of hormone bound to plasma proteins - rate of hormone metabolism

Question 35

what does rate of hormone secretion depend on

Answer 35

- release of chemical messages by cells at variable rates - neural and humoral signals influence increase and decrease rate of secretion - whether its an ongoing process or not

Question 36

how do neural signals regulate hormone secretion

Answer 36

- directly - using hypothalamus (w/ tropic hormones); posterior pituitary (w/ ADH and oxytocin); adrenal medulla (w/ epinephrine)

Question 37

describe hormone actions during stress

Answer 37

neural signals travel to hypothalamus which triggers CRH release, anterior pituitary releases ACTH and adrenal cortex releases cortisol

Question 38

what are the categories of humoral signals

Answer 38

hormones, ions, metabolites

Question 39

describe the regulation of blood glucose levels

Answer 39

blood glucose increases which causes insulin release in pancreas beta cells and glucose uptake in all cells through body which decreases blood glucose levels (negative feedback)

Question 40

describe the regulation of blood potassium levels

Answer 40

blood potassium increases which causes aldosterone release in adrenal cortex and potassium excretion in kidneys which causes blood potassium to go down (negative feedback)

Question 41

describe hydrophilic hormones

Answer 41

- dissolve in plasma - EX peptides, catecholamines

Question 42

describe hydrophobic hormones

Answer 42

- transport in blood bound to carrier proteins - only free hormones bind to receptors and have ability to be metabolized - longer half-life

Question 43

what are examples of abnormal hormone secretion

Answer 43

- hypersecretion - hyposecretion

Question 44

describe primary hypersecretion of cortisol

Answer 44

- abnormality in endocrine gland that secretes hormone - there is excess cortisol secretion which means that there are decreased levels of ACTH and CRH but regulation is inadequate and won't help to bring cortisol down (negative feedback)

Question 45

describe secondary hypersecretion of cortisol

Answer 45

- abnormality with endocrine cells of anterior pituitary or hypothalamus which secrete tropic hormone - EX excess ACTH in ant pit which causes excess cortisol secretion in adrenal gland which also leads to CRH decrease but none of the 2 regulations are enough to bring the ACTH back down

Question 46

what are the ways a hormone can interact

Answer 46

antagonism, additive effect, synergism, permissiveness

Question 47

describe antagonism

Answer 47

effects of hormones opposing e/o (glucagon vs insulin)

Question 48

describe additive effect

Answer 48

net effect equals sum of individual effects

Question 49

describe synergism

Answer 49

effects of 2 hormones favour e/o but net effect exceeds sum of individual effects

Question 50

describe permissiveness

Answer 50

one hormone is needed for another to exert its effects (thyroid hormones needed for expression of beta adrenergic receptors in bronchiolar smooth muscle)