Endocrine System Flashcards Preview

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Flashcards in Endocrine System Deck (43)
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1
Q

Where do endocrine glands secrete hormones to?

A

-Directly into circulatory system

2
Q

Where do exocrine glands substances go?

A

-Transport by ducts

3
Q

What determines the specificty of hormonal action?

A

-Specific receptors on/in target cells

4
Q

What secretes adrenocortical steroids (corticosteroids)?

A
  • Adrenal cortex

- Stimulated by ACTH produced by anterior pituitary

5
Q

How do corticosteroids function?

A

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

6
Q

How are corticosteroids transported in bloodstream?

A

-Transcortins

7
Q

What are the 3 major classes of corticosteroids?

A
  • Glucocorticoids
  • Mineralocorticoids
  • Cortical sex hormones
8
Q

Glucocorticoids include…

A
  • 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
Q

What is an example of mineralocorticoids?

A
  • Aldosterone - regulates plasma Na+/K+ levels
  • Active reabsorption of Na+/passive reabsorption of H2O
  • Increase blood volume/pressure
10
Q

What stimulates mineralocorticoids? Inhibits?

A
  • Angiotensin II

- ANP

11
Q

Where are most androgens produced in men?

A

-Testes

12
Q

What produces catecholamines?

A
  • Adrenal medulla

- E.g. Neurotransmitters: Epinephrine and Norepinephrine

13
Q

What are the effects of epinephrine?

A
  • 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
Q

What connects the pituitary gland to hypothalamus?

A

-Infundibulum

15
Q

What regulates anterior pituitary gland secretions?

A

-Releasing hormones from hypothalamus

16
Q

What type of hormones does the anterior pituitary secrete?

A

-Direct and tropic hormones

17
Q

What are the direct hormones of the anterior pituitary?

A
  • Growth Hormone (GH, somatotropin)

- Prolactin

18
Q

What is acromegaly?

A

-Overproduction of GH in adults

19
Q

What are the tropic hormones of the anterior pituitary?

A
  • 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
Q

What is the role of the posterior pituitary?

A

-Store/release peptide hormones, oxytocin and ADH

21
Q

When is ADH released?

A
  • Plasma osmolarity increases (sense by osmoreceptors in hypothalamus)
  • Blood volume decreases (sense by baroreceptors in circulatory system)
22
Q

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

A
  • Pituitary gland secretions by negative feedback

- Use of Inhibiting/releasing hormones

23
Q

What does GnRH do?

A

-Stimulate anterior pituitary to secrete FSH/LH

24
Q

How do releasing hormones function?

A
  • Secreted into hypothalamic-hypophyseal portal system

- Blood from capillary bed in hypothalamus –> portal vein –> anterior pituitary –> secondary capillary network

25
Q

Neurosecretory cells in hypothalamus synthesize…

A

…oxytocin and ADH

26
Q

How do hormones of hypothalamus reach posterior pituitary?

A

-Via hypothalmus axons

27
Q

What are the thyroid hormones?

A
  • Thyroxine (T4) and triiodothyronine (T3)

- Formed from glycoprotein thyroglobulin

28
Q

Which thyroid hormone is more potent?

A

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

29
Q

How are T3 and T4 transported?

A

-Bound to plasma proteins

30
Q

Hypothyroidism is characterized by…

A
  • TH low
  • Slow HR/breathing, fatigue, cold, weight gain
  • Cretinism (young) retardation/short
31
Q

Hyperthyroidism is characterized by…

A
  • Overstimulated thyroid

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

32
Q

What is the role of calcitonin?

A
  • Decrease plasma Ca++ by inhibiting release from bone

- Antagonistic to parathyroid hormone

33
Q

Why is the pancreas both endocrine and exocrine organ?

A
  • Secreted digestive enzymes (exocrine)

- Islets of Langerhans (endocrine)

34
Q

What do alpha cells produce/secrete?

A
  • Glucagon - protein/fat degradation, glycogen –> glucose, gluconeogenesis
  • Increase blood glucose levels
  • Antagonistic to insulin
35
Q

What do beta cells produce/secrete?

A

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

36
Q

What does parathyroid hormone do?

A
  • 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
Q

What does renin do?

A
  • Produced by kidneys
  • Enzyme converts plasma protein angiotensinogen to angiotensin I which is converted to angiotensin II stimulates secretion of aldosterone
38
Q

What does EPO stimulate?

A
  • Produced by kidneys

- Stimulates RBC production

39
Q

What does the pineal gland secrete?

A
  • Melatonin
  • May help regulate circadian rhythms
  • Antagonist to MSH in primitive vertebrates
40
Q

Which type of hormone is first messenger?

A
  • Peptide hormones

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

41
Q

Where are steroid hormones produced?

A

-Testes, ovaries, placenta, adrenal cortex

42
Q

Which hormones can cross the phospholipid bilayer?

A
  • Steroid –> enter and target cells directly to bind receptor proteins in cytoplasm
  • Directly activates expression of certain genes
43
Q

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

A

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