Endocrine System Part 1

Question 1

Exocrine glands secrete products through

Answer 1

ducts

Question 2

Endocrine glands secrete hormones into the

Answer 2

blood

Question 3

Major endocrine glands

Answer 3

• Pituitary
• Pineal gland
• Thyroid gland
• Parathyroid glands
• Adrenal glands

Question 4

Hypothalamus controls the

Answer 4

pituitary gland

Question 5

hypothalamus secretes

Answer 5

• thyrotropin-releasing hormone (TRH)
• Oxytocin
• Vasopressin (ADH)
• somatostatin (SST)

Question 6

thymus secretes

Answer 6

thymopoietin and thymosins

Question 7

hearts secretes

Answer 7

atriopeptin

Question 8

kidneys secrete

Answer 8

calcitriol and erythropoietin

Question 9

GI tract secretes

Answer 9

CKK, GIP, gastrin, secretin, VIP

Question 10

pancreatic islets secrete

Answer 10

Glucagon, insulin, somatostatin, pancreatic polypeptide

Question 11

testes secrete

Answer 11

Androgens
* Spermatogenesis
* Growth
* Secondary sexual characteristics

Question 12

ovaries secrete

Answer 12

Estrogen
* Oogenesis – egg development
* Breast development
* Ovulation

Progesterone
* From corpus luteum in ovary
* Promotes secretion from endometrium
* Matures breasts for lactation

Question 13

pituitary gland secretes

Answer 13

• follicle-stimulating hormone (FSH)
• lutenizing hormone (LH)
• adrenocorticotropic hormone (ACTH)
• thyroid-stimulating hormone (TSH)
• Prolactin
• growth hormone (GH)
• melanocyte-stimulating hormone (MSH)

Question 14

pineal

Answer 14

melatonin

Question 15

parathyroid secretes

Answer 15

parathyroid hormone (PTH)

Question 16

adrenal glands secrete

Answer 16

Cortex: corticosteroids

glomerulosa: aldosterone

fasciculata: cortisol

reticularis: androgens

Medulla: epinephrine, norepinephrine

Question 17

Three major chemical classes of hormones:

Answer 17

1. Amines
2. Peptides and proteins
3. Steroids

Question 18

Amine Hormones

Answer 18

Derived from the amino acid tyrosine

Catecholamines
* Epinephrine & Norepinephrine
* From adrenal gland (medulla)

Dopamine
* From hypothalamus

Thyroid hormones (Like steroids- fat-soluble)
* T3 & T4 (thyroxine)
* From thyroid gland Tyrosine

Question 19

Peptide and Protein Hormones

Answer 19

• Synthesized as a preprohormone
• Cleaved to a prohormone in rough ER
• Cleaved to active hormone in Golgi
• Hormone and other fragments secreted together

Question 20

pancreas secretes

Answer 20

• insulin
• glucagon
• renin (Kidney)
• angiotensin (Liver)
• atrial natriuretic peptide (ANP)
  (Heart)

Question 21

Steroid Hormones

Answer 21

• From a cholesterol precursor (lipids)
• Produced by adrenal cortex and gonads (testes/ovaries)
• Stimulated by anterior pituitary hormones
• Via G-protein coupled receptor

Question 22

Calcitrol synthesis (Active Vitamin D3)

Answer 22

• Cholesterol-derived precursor (obtained from the diet)
• Converted to Vitamin D3 in skin
• Energy from UV light
• Hydroxyl groups added in liver and kidneys
• Active hormone is 1,25-dihydroxyvitamin D3
• AKA Calcitrol

Question 23

Peptide & catecholamine hormones

Answer 23

– Hydrophilic
– Water-soluble
– Dissolved in plasma
-Unbound
-Respond fast

Question 24

Steroid and thyroid hormones

Answer 24

– Poorly soluble
– Mostly bound to plasma proteins
– Small concentrations dissolved in plasma
(“free hormones”)
– Only free hormones interact with target cells
-Respond slowly

Question 25

Blood concentration depends on:

Answer 25

1. Rate of secretion 2. Rate of removal

Question 26

Clearance rates:

Answer 26

* Peptides & Catecholamines * Minutes to an hour * Steroids (bound to carrier) * Hours to days

Question 27

Hyposecretion

Answer 27

* Too little hormone * Primary (main hormone) vs. Secondary (tropic hormone)

Question 28

Hypersecretion

Answer 28

* Too much hormone * Primary vs. Secondary

Question 29

Hyporesponsiveness

Answer 29

Too little response from target cell * Ex.: Type II Diabetes

Question 30

Hyperresponsiveness

Answer 30

Too big of response from target cell * Ex.: Thyroid hormone= beta adrenergic receptors

Question 31

Up-regulation

Answer 31

* More receptors * Due to prolonged, low exposure to hormone * Increases target cell responsiveness Ex: Estrogen upregulates progesterone receptors in the uterus. This makes the uterus more responsive to progesterone, which is essential for pregnancy maintenance.

Question 32

Secretion of hormones controlled by:

Answer 32

1. Ions or nutrients in plasma * Ex.: Ca2+ or glucose 2. Neurotransmitters released onto target from axon terminal * Ex.: Hypothalamus= posterior pituitary, Adrenal medulla 3. Tropic hormones * Anterior pituitary hormones

Question 33

Describe the negative feedback control of insulin secretion

Answer 33

Increase in plasma glucose concentration Increase in insulin secretion Increase in plasma insulin concentration Transport glucose to intracellular fluid