Biology 5: The Endocrine System

Question 1

Hypophyseal portal system

Answer 1

blood vessel system that directly connects the hypothalamus with the anterior pituitary

Question 2

Hypophysis

Answer 2

neural connection between the hypothalamus and posterior pituitary

the hypothalamus sends axons down the stalk, doesn’t secrete any hormones

Question 3

C-cells

Answer 3

cells in the thyroid that produce calcitonin

Question 4

Calcitonin

Answer 4

decreases plasma calcium levels

decreases calcium absorption in the gut

increases calcium secretion in kidneys

increases storage of calcium in bone

Question 5

Parathyroid Hormone (PTH)

Answer 5

increases plasma calcium levels

decreases storage of calcium in bone

acts antagonistically to calcitonin

resorbs phosphate from bone

decreases absorption of phosphate from kidney

activates vitamin D

Question 6

Vitamin D

Answer 6

required for the absorption of calcium and phosphate in the gut

Question 7

Aldosterone

Answer 7

increases sodium reabsorption in the distal convoluted tubule and collecting duct of the nephron

Question 8

Renin

Answer 8

cleaves angiotensinogen to angiotensin I

angiotensin II stimulates the adrenal cortex to secrete aldosterone

Question 9

alpha cells

Answer 9

secrete glucagon

Question 10

beta cells

Answer 10

secrete insulin

Question 11

delta cells

Answer 11

secrete somatostatin

suppresses the secretion of glucagon and insulin

Question 12

Glucagon

Answer 12

secreted during times of fasting

stimulates degradation of protein and fat, conversion of glycogen to glucose, and production of new glucose via gluconeogenesis

Question 13

Type I diabetes mellitus

Answer 13

diabetes caused by autoimmune destruction of the beta cells of the pancreas

Question 14

Type II diabetes mellitus

Answer 14

diabetes as a result of receptor-level resistance to the effects of insulin

Question 15

Somatostatin

Answer 15

inhibitor of both insulin and glucagon secretion

produced by delta cells

stimulated by high blood glucose and amino acid secretions

Question 16

Erythropoietin

Answer 16

stimulates bone marrow to increase production of erythrocytes

secreted in response to low oxygen levels in the blood

Question 17

atrial natriuretic peptide

Answer 17

promotes excretion of sodium and therefore increases urine volume

Question 18

thymosin

Answer 18

important for proper T-cell development and differentiation

secreted by the thymus

Question 19

what are the three types of hormones?

Answer 19

those derived from peptides, steroids, or amino acids

Question 20

peptide hormones

Answer 20

hormones derived from large precursor polypeptides cleaved in Golgi during posttranslational modification

charged, and cannot pass through membrane – uses a signaling cascade (cAMP, IP3, Ca2+)

produces rapid, short-lived effects in cells

water-soluble in blood, don’t require carriers

ex. insulin

Question 21

steroid hormones

Answer 21

hormones derived from cholesterol, produced mostly from gonads and adrenal cortex

nonpolar, can cross membrane to join with intracellular and intranuclear receptors

slower, longer lived effects

not water-soluble, have protein carriers in blood

ex. estrogen

Question 22

what happens if you have too many hormone carriers in the blood?

Answer 22

then you have a lot of hormone bound to the protein carrier and not enough free hormone available

the hormone cannot bind to receptors if it is bound to its carrier

Question 23

amino acid derivative hormones

Answer 23

hormones derived from one or two amino acids with additional modifications

less common type of hormone

include catecholamines (epinephrine and norepinephrine) that binds G-protein coupled receptor

and thyroid hormones that bind intracellularly

Question 24

direct hormones

Answer 24

hormones which are secreted and act directly on their target tissues

Question 25

tropic hormones

Answer 25

hormones that require an intermediary to act on the target tissue usually secreted from the brain and anterior pituitary gland

Question 26

GnRH

Answer 26

**Gonadotropin-Releasing hormone** released by the hypothalamus, triggers the release of **FSH and LH** which act on the **gonads**

Question 27

GHRH

Answer 27

**Growth-hormone-releasing hormone** stimulates the release of **growth hormone (GH)** from the anterior pituitary growth hormone **promotes the growth of bone and muscle** prevents glucose uptake for certain tissues, stimulates breakdown of fatty acids to allow for **more glucose overall**

Question 28

TRH

Answer 28

**thyroid-releasing hormone** triggers the release of **thyroid-stimulating hormone (TSH)** from anterior pituitary TSH acts on thyroid to release T3 and T4

Question 29

CRF

Answer 29

**corticotropin-releasing factor** triggers the release of **adrenocorticotropin hormone (ACTH)** from the anterior pituitary ACTH causes the release of **cortisol**

Question 30

PIF

Answer 30

prolactin-inhibiting factor (dopamine) triggers a decrease in prolactin secretion, causing a decrease in milk production

Question 31

oxytocin

Answer 31

**hormone** released by the posterior pituitary cause smooth muscle contraction, uterine contractions somehow involved in bonding invloved in positive feedback loop

Question 32

ADH / vasopressin

Answer 32

hormone released in response to low blood volume or increased blood osmolarity (lots of solutes) increases permeability of collecting duct to water

Question 33

thyroid

Answer 33

gland on the front surface of the trachea sets bmr and maintains calcium homeostasis

Question 34

follicular cells

Answer 34

cells in the thyroid that produce T3 and T4 from the iodination of tyrosine

Question 35

glucocorticoid

Answer 35

steroid hormones secreted by the adrenal cortex in response to ACTH raise blood glucose by increasing gluconeogenesis and decreasing protein synthesis decrease inflammation and immune responses ex. cortisol and cortisone

Question 36

mineralocorticoids

Answer 36

hormones released by the adrenal cortex ex. aldosterone **increase sodium reabsorption** in distal tube and collecting ducts increase water retention; **increasing blood volume and pressure** decrease potassium reabsorption

Question 37

cortical sex hormones

Answer 37

hormones produced by the adrenal cortex ex. androgens and estrogens promoting sexual characteristics and the maturation of reproductive organs of the respective gender

Question 38

what are the three types of corticosteroids?

Answer 38

mineralocorticoids (**salt**) glucocorticoids (**sugar**) cortical sex hormones (**sex**)