Endocrine System

Question 1

Where do endocrine glands secrete hormones to?

Answer 1

-Directly into circulatory system

Question 2

Where do exocrine glands substances go?

Answer 2

-Transport by ducts

Question 3

What determines the specificty of hormonal action?

Answer 3

-Specific receptors on/in target cells

Question 4

What secretes adrenocortical steroids (corticosteroids)?

Answer 4

• Adrenal cortex

- Stimulated by ACTH produced by anterior pituitary

Question 5

How do corticosteroids function?

Answer 5

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

Question 6

How are corticosteroids transported in bloodstream?

Answer 6

-Transcortins

Question 7

What are the 3 major classes of corticosteroids?

Answer 7

• Glucocorticoids
• Mineralocorticoids
• Cortical sex hormones

Question 8

Glucocorticoids include…

Answer 8

• 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

Question 9

What is an example of mineralocorticoids?

Answer 9

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

Question 10

What stimulates mineralocorticoids? Inhibits?

Answer 10

• Angiotensin II

- ANP

Question 11

Where are most androgens produced in men?

Answer 11

-Testes

Question 12

What produces catecholamines?

Answer 12

• Adrenal medulla

- E.g. Neurotransmitters: Epinephrine and Norepinephrine

Question 13

What are the effects of epinephrine?

Answer 13

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

Question 14

What connects the pituitary gland to hypothalamus?

Answer 14

-Infundibulum

Question 15

What regulates anterior pituitary gland secretions?

Answer 15

-Releasing hormones from hypothalamus

Question 16

What type of hormones does the anterior pituitary secrete?

Answer 16

-Direct and tropic hormones

Question 17

What are the direct hormones of the anterior pituitary?

Answer 17

• Growth Hormone (GH, somatotropin)

- Prolactin

Question 18

What is acromegaly?

Answer 18

-Overproduction of GH in adults

Question 19

What are the tropic hormones of the anterior pituitary?

Answer 19

• 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

Question 20

What is the role of the posterior pituitary?

Answer 20

-Store/release peptide hormones, oxytocin and ADH

Question 21

When is ADH released?

Answer 21

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

Question 22

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

Answer 22

• Pituitary gland secretions by negative feedback

- Use of Inhibiting/releasing hormones

Question 23

What does GnRH do?

Answer 23

-Stimulate anterior pituitary to secrete FSH/LH

Question 24

How do releasing hormones function?

Answer 24

• Secreted into hypothalamic-hypophyseal portal system

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

Question 25

Neurosecretory cells in hypothalamus synthesize...

Answer 25

...oxytocin and ADH

Question 26

How do hormones of hypothalamus reach posterior pituitary?

Answer 26

-Via hypothalmus axons

Question 27

What are the thyroid hormones?

Answer 27

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

Question 28

Which thyroid hormone is more potent?

Answer 28

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

Question 29

How are T3 and T4 transported?

Answer 29

-Bound to plasma proteins

Question 30

Hypothyroidism is characterized by...

Answer 30

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

Question 31

Hyperthyroidism is characterized by...

Answer 31

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

Question 32

What is the role of calcitonin?

Answer 32

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

Question 33

Why is the pancreas both endocrine and exocrine organ?

Answer 33

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

Question 34

What do alpha cells produce/secrete?

Answer 34

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

Question 35

What do beta cells produce/secrete?

Answer 35

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

Question 36

What does parathyroid hormone do?

Answer 36

- 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

Question 37

What does renin do?

Answer 37

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

Question 38

What does EPO stimulate?

Answer 38

- Produced by kidneys | - Stimulates RBC production

Question 39

What does the pineal gland secrete?

Answer 39

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

Question 40

Which type of hormone is first messenger?

Answer 40

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

Question 41

Where are steroid hormones produced?

Answer 41

-Testes, ovaries, placenta, adrenal cortex

Question 42

Which hormones can cross the phospholipid bilayer?

Answer 42

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

Question 43

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

Answer 43

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