Endocrine System

Question 1

What does the endocrine system do?

Answer 1

• secretes chemicals (hormones) into blood
• is then transported to target cells via circulation and act on target cells

Question 2

What is a target cell?

Answer 2

a cell with a receptor specific for a hormone

Question 3

What are the 3 hormone classes?

Answer 3

steroids, hormones derived from amino acids, and peptide + protein hormones

Question 4

Describe steroid hormones

Answer 4

• synthesized from cholesterol (lipid soluble)
• testosterone, estrogen, vitamin D

Question 5

Describe peptide and protein hormones

Answer 5

• chains of amino acids
• mainly water soluble
• ex: oxytocin, antidiuretic hormone (ADH), growth hormone (GH), insulin

Question 6

Where is the pituitary gland located? What is it connected to?

Answer 6

Connected to hypothalamus in the sella turcica of the sphenoid bone

Question 7

What are the 2 lobes of the pituitary gland called? What type of tissue are they made of?

Answer 7

• anterior: epithelial
• posterior: nervous

Question 8

What regulates the hormones the anterior pituitary releases?

Answer 8

hormones secreted by the hypothalamus

Question 9

what metabolism hormones does the anterior pituitary gland release?

Answer 9

growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone

Question 10

what reproductive hormones does the anterior pituitary release?

Answer 10

luteinizing hormone, follicle stimulating hormone, prolactin

Question 11

what does prolactin do?

Answer 11

stimulates milk formation

Question 12

the posterior pituitary is an extension of…?

Answer 12

the hypothalamus

Question 13

hormones produced in the hypothalamus are…?

Answer 13

stored and secreted from the posterior pituitary gland

Question 14

what hormones does the posterior pituitary gland secrete?

Answer 14

oxytocin, and antidiuretic hormone

Question 15

what does oxytocin do?

Answer 15

stimulates uterine contractions and milk ejection

Question 16

what does the antidiuretic hormone do?

Answer 16

water reabsorption in kidney

Question 17

describe the thyroid glands location and shape

Answer 17

butterfly shaped, on anterior surface of the superior part of the trachea

Question 18

what is the histology of the thyroid gland?

Answer 18

follicles - walls made up of epithelial cells (follicle cells), produces T4

Parafollicular cells - between follicles, secrete calcitonin which increases calcium uptake into bone formation which lowers blood calcium

Question 19

what does the parathyroid gland do?

Answer 19

secrete parathyroid hormone

Question 20

what does the parathyroid hormone do?

Answer 20

increases blood calcium by:
- increased calcium release from bone (= bone resorption) - activates osetoclasts

• decreased calcium loss in urine (kidney)
• increased vitamin D activation (kidney), Vitamin D then increases calcium absorption at the small intestine

Question 21

where are adrenal glands located?

Answer 21

superior surface of each kidney

Question 22

what are the 2 parts of the adrenal glands, and what are they made of?

Answer 22

• adrenal cortex (outer), made up of epithelial tissue

-adrenal medulla (inner), made up of nervous tissue

Question 23

the adrenal cortex secretes what?

Answer 23

steroids only!

Question 24

what are the 3 layers of the adrenal cortex ?

Answer 24

• zona glomerulosa
• zona fasciculata
• zona reticularis

Question 25

what does the zona glomerulosa do?

Answer 25

secretes mineralocorticoids (mainly aldosterone), balances salt

Question 26

what does the zona fasciculata do?

Answer 26

secretes glucocorticoids (eg. cortisol), long term stress hormone and carbohydrate metabolism

Question 27

what does the zona reticularis do?

Answer 27

secretes androgens and small amounts of testosterone, some converted to estrogens in other tissues (especially fat)

Question 28

what hormones does the adrenal medulla secrete?

Answer 28

(80%) epinephrine and (20%) norepinephrine

Question 29

what do the cells of the pancreatic islets of langerhans do?

Answer 29

alpha cells- produce glucagon, which increases blood glucose

beta cells- produce insulin, which decreases blood glucose

Question 30

hypothalamus regulates the anterior pituitary using what hormones?

Answer 30

growth hormone releasing hormone, growth hormone inhibiting hormone, gonadotropin releasing hormone

Question 31

what hormone does the testes release?

Answer 31

testosterone via the leydig cells

Question 32

what hormones do the ovaries release

Answer 32

-estrogen via cells of secondary and vesicular follicles

-estrogen + progesterone via corpus luteum

Question 33

what other organs have edocrine functions?

Answer 33

~kidney - renin
~duodenum - secretin
~skin - Vitamin D
~heart - atrial natriuretic peptide (ANP)
~etc….