Biology 5: The Endocrine System Flashcards

1
Q

Hypophyseal portal system

A

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

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2
Q

Hypophysis

A

neural connection between the hypothalamus and posterior pituitary

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

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3
Q

C-cells

A

cells in the thyroid that produce calcitonin

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4
Q

Calcitonin

A

decreases plasma calcium levels

decreases calcium absorption in the gut

increases calcium secretion in kidneys

increases storage of calcium in bone

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5
Q

Parathyroid Hormone (PTH)

A

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

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6
Q

Vitamin D

A

required for the absorption of calcium and phosphate in the gut

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7
Q

Aldosterone

A

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

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8
Q

Renin

A

cleaves angiotensinogen to angiotensin I

angiotensin II stimulates the adrenal cortex to secrete aldosterone

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9
Q

alpha cells

A

secrete glucagon

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10
Q

beta cells

A

secrete insulin

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11
Q

delta cells

A

secrete somatostatin

suppresses the secretion of glucagon and insulin

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12
Q

Glucagon

A

secreted during times of fasting

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

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13
Q

Type I diabetes mellitus

A

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

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14
Q

Type II diabetes mellitus

A

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

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15
Q

Somatostatin

A

inhibitor of both insulin and glucagon secretion

produced by delta cells

stimulated by high blood glucose and amino acid secretions

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16
Q

Erythropoietin

A

stimulates bone marrow to increase production of erythrocytes

secreted in response to low oxygen levels in the blood

17
Q

atrial natriuretic peptide

A

promotes excretion of sodium and therefore increases urine volume

18
Q

thymosin

A

important for proper T-cell development and differentiation

secreted by the thymus

19
Q

what are the three types of hormones?

A

those derived from peptides, steroids, or amino acids

20
Q

peptide hormones

A

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

21
Q

steroid hormones

A

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

22
Q

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

A

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

23
Q

amino acid derivative hormones

A

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

24
Q

direct hormones

A

hormones which are secreted and act directly on their target tissues

25
Q

tropic hormones

A

hormones that require an intermediary to act on the target tissue

usually secreted from the brain and anterior pituitary gland

26
Q

GnRH

A

Gonadotropin-Releasing hormone

released by the hypothalamus, triggers the release of FSH and LH which act on the gonads

27
Q

GHRH

A

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

28
Q

TRH

A

thyroid-releasing hormone

triggers the release of thyroid-stimulating hormone (TSH) from anterior pituitary

TSH acts on thyroid to release T3 and T4

29
Q

CRF

A

corticotropin-releasing factor

triggers the release of adrenocorticotropin hormone (ACTH) from the anterior pituitary

ACTH causes the release of cortisol

30
Q

PIF

A

prolactin-inhibiting factor (dopamine)

triggers a decrease in prolactin secretion, causing a decrease in milk production

31
Q

oxytocin

A

hormone released by the posterior pituitary

cause smooth muscle contraction, uterine contractions

somehow involved in bonding

invloved in positive feedback loop

32
Q

ADH / vasopressin

A

hormone released in response to low blood volume or increased blood osmolarity (lots of solutes)

increases permeability of collecting duct to water

33
Q

thyroid

A

gland on the front surface of the trachea

sets bmr and maintains calcium homeostasis

34
Q

follicular cells

A

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

35
Q

glucocorticoid

A

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

36
Q

mineralocorticoids

A

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

37
Q

cortical sex hormones

A

hormones produced by the adrenal cortex

ex. androgens and estrogens

promoting sexual characteristics and the maturation of reproductive organs of the respective gender

38
Q

what are the three types of corticosteroids?

A

mineralocorticoids (salt)

glucocorticoids (sugar)

cortical sex hormones (sex)