Endocrine System Flashcards Preview

Biology > Endocrine System > Flashcards

Flashcards in Endocrine System Deck (43):
1

Where do endocrine glands secrete hormones to?

-Directly into circulatory system

2

Where do exocrine glands substances go?

-Transport by ducts

3

What determines the specificty of hormonal action?

-Specific receptors on/in target cells

4

What secretes adrenocortical steroids (corticosteroids)?

-Adrenal cortex
-Stimulated by ACTH produced by anterior pituitary

5

How do corticosteroids function?

-Determine which genes of target cell are transcribed and at what rate

6

How are corticosteroids transported in bloodstream?

-Transcortins

7

What are the 3 major classes of corticosteroids?

-Glucocorticoids
-Mineralocorticoids
-Cortical sex hormones

8

Glucocorticoids include...

-Cortisol/Cortisone
-Raise blood glucose levels (protein breakdown/ gluconeogenesis/ lower protein syn)
-Increase plasma glucose levels
-Release amino acids (skeletal muscle) and lipids (adipose)
-Anti-inflammatory

9

What is an example of mineralocorticoids?

-Aldosterone - regulates plasma Na+/K+ levels
-Active reabsorption of Na+/passive reabsorption of H2O
-Increase blood volume/pressure

10

What stimulates mineralocorticoids? Inhibits?

-Angiotensin II
-ANP

11

Where are most androgens produced in men?

-Testes

12

What produces catecholamines?

-Adrenal medulla
-E.g. Neurotransmitters: Epinephrine and Norepinephrine

13

What are the effects of epinephrine?

-Increase glycogen --> glucose (liver/muscle)
-Increase basal metabolic rate
-Dilate/constrict blood vessel (>blood flow to skeletal muscle/heart/brain)
-Release lipids by adipose

14

What connects the pituitary gland to hypothalamus?

-Infundibulum

15

What regulates anterior pituitary gland secretions?

-Releasing hormones from hypothalamus

16

What type of hormones does the anterior pituitary secrete?

-Direct and tropic hormones

17

What are the direct hormones of the anterior pituitary?

-Growth Hormone (GH, somatotropin)
-Prolactin

18

What is acromegaly?

-Overproduction of GH in adults

19

What are the tropic hormones of the anterior pituitary?

-Adrenocorticotropic hormone (ACTH)
-Thyroid-Stimulating Hormone (TSH)
-Luteinizing hormone (LH) - ovulation/corpus luteum or testes to produce testosterone
-Follicle-Stimulating Hormone (FSH) -maturation of ovarian follicles/seminiferous tubules and sperm production
-Melanocyte-stimulating Hormone (MSH) - darken frog
-Endorphins - Neurotransmitters

20

What is the role of the posterior pituitary?

-Store/release peptide hormones, oxytocin and ADH

21

When is ADH released?

-Plasma osmolarity increases (sense by osmoreceptors in hypothalamus)
-Blood volume decreases (sense by baroreceptors in circulatory system)

22

What do the neurosecretory cells of the hypothalamus regulate? How?

-Pituitary gland secretions by negative feedback
-Use of Inhibiting/releasing hormones

23

What does GnRH do?

-Stimulate anterior pituitary to secrete FSH/LH

24

How do releasing hormones function?

-Secreted into hypothalamic-hypophyseal portal system
-Blood from capillary bed in hypothalamus --> portal vein --> anterior pituitary --> secondary capillary network

25

Neurosecretory cells in hypothalamus synthesize...

...oxytocin and ADH

26

How do hormones of hypothalamus reach posterior pituitary?

-Via hypothalmus axons

27

What are the thyroid hormones?

-Thyroxine (T4) and triiodothyronine (T3)
-Formed from glycoprotein thyroglobulin

28

Which thyroid hormone is more potent?

T3 (only 30% produced by thyroid vs 100% of T4)

29

How are T3 and T4 transported?

-Bound to plasma proteins

30

Hypothyroidism is characterized by...

-TH low
-Slow HR/breathing, fatigue, cold, weight gain
-Cretinism (young) retardation/short

31

Hyperthyroidism is characterized by...

-Overstimulated thyroid
-High metabolic rate, warmth, sweating, palpitations, weight loss, protruding eyes

32

What is the role of calcitonin?

-Decrease plasma Ca++ by inhibiting release from bone
-Antagonistic to parathyroid hormone

33

Why is the pancreas both endocrine and exocrine organ?

-Secreted digestive enzymes (exocrine)
-Islets of Langerhans (endocrine)

34

What do alpha cells produce/secrete?

-Glucagon - protein/fat degradation, glycogen --> glucose, gluconeogenesis
-Increase blood glucose levels
-Antagonistic to insulin

35

What do beta cells produce/secrete?

-Insulin - uptake glucose by muscle/adipose, store glucose as glycogen, synthesize fats from glucose, uptake aa

36

What does parathyroid hormone do?

-Regulate plasma Ca++ by increasing release from bone, decrease excretion by kidneys
-Ca++ in bone bound to phosphorus so breakdown also increases phosphorus
-Increase excretion of phosphorus in kidneys

37

What does renin do?

-Produced by kidneys
-Enzyme converts plasma protein angiotensinogen to angiotensin I which is converted to angiotensin II stimulates secretion of aldosterone

38

What does EPO stimulate?

-Produced by kidneys
-Stimulates RBC production

39

What does the pineal gland secrete?

-Melatonin
-May help regulate circadian rhythms
-Antagonist to MSH in primitive vertebrates

40

Which type of hormone is first messenger?

-Peptide hormones
-Bind to specific receptors on surgace og target and trigger rxns

41

Where are steroid hormones produced?

-Testes, ovaries, placenta, adrenal cortex

42

Which hormones can cross the phospholipid bilayer?

-Steroid --> enter and target cells directly to bind receptor proteins in cytoplasm
-Directly activates expression of certain genes

43

-What are some of the releasing hormones of the hypothalamus?

-GnRH, GHRH, CRF, Somatostatin (inhibits GH), dopamine (inhibits prolactin)