15CHAPTER 17: THE ENDOCRINE SYSTEM

Question 1

Why must cells be able to communicate and integrate their activities with each other?

Answer 1

gap junction,

To maintain body homeostasis

Question 2

What are the 4 methods of cellular communication?

Answer 2

Gap junctions, neurotransmitters, paracrine signals, and hormones

Question 3

Where are gap junctions present are and what do they do?

Answer 3

Present in some neurons, cardiac and smooth muscle

Allow direct communication via signalling molecules

Question 4

What doe neurotransmitters secreted by and what do they do?

Answer 4

Secreted by neurons

Act less directly than gap junctions, release neurotransmitters on postsynaptic neurons that have the correct receptor

Question 5

What are paracrine signals secreted into?

Answer 5

Secreted into tissue fluids by a cell and affect nearby cells in same tissue

Question 6

What are hormones?

Answer 6

Chemical messengers secreted by endocrine glands (and others) into the bloodstream

Question 7

What does the endocrine system include?

Answer 7

Glands and organs (brain, heart, small intestine) that secrete hormones into the blood

Question 8

How does communication occur within the nervous system and the endocrine system?

Answer 8

NS- neurotransmitter

ES- hormones

Question 9

Where are chemicals released into from the Nervous system and the endocrine system?

Answer 9

NS- into synaptic cleft ES- into blood

Question 10

What are the effects of the NS and the ES?

Answer 10

NS-short acting ES- longer acting

Question 11

What is the Speed of reactions withing the NS and ES?

Answer 11

NS- fast – seconds , ES- slow – minutes to days

Question 12

What does the hypothalamus (HYP) form?

Answer 12

Floor and walls of the 3rd ventricle.

Question 13

What is the pituitary gland composed of?

Answer 13

Two structures:

• Posterior pituitary (neurohypophysis)
• Anterior pituitary (adenohypophysis)

Question 14

What do the hormones of the hypothalamus do?

Answer 14

6 stimulate or inhibit anterior pituitary

2 secrete by way of posterior pituitary

Question 15

Which hormones are the posterior pituitary (PP) hormones?

Answer 15

ADH (antidiuretic hormone) and OT (oxytocin)

Question 16

What is the action of ADH (antidiuretic hormone)?

Answer 16

Water reabsorption

Question 17

What is the action of OT (oxytocin)?

Answer 17

Contraction of uterus (childbirth)

Contraction of mammary gland cells (milk secretion)

Question 18

What are the anterior pituitary hormones?

Answer 18

FSH (follicle-stimulating H.), 
LH (luteinizing H.), 
TSH (thyroid-stimulating H.),
ACTH (adrenocorticotropic H.), 
PRL (prolactin), 
GH (growth H.)

Question 19

What are the 3 chemical classes of hormones?

Answer 19

Steroids, peptides, monoamines

Question 20

What are steroids synthesized from?

Answer 20

Cholesterol

Examples: sex H., vit D, corticosteroids, aldosterone, estrogen

Question 21

What are peptides synthesized from?

Answer 21

Amino acids

Ex. Oxytocin, ADH, insulin

Question 22

What are monoamines synthesized from?

Answer 22

Amino acids Tryptophan (melatonin) and Tyrosine (EPI, NE)

Question 23

What kind of solution is blood plasma?

Answer 23

Aqueous solution (mostly water)

Question 24

What is the difference is life length between hydrophobic hormones and hydrophilic hormones?

Answer 24

hydrophobic hormones- prolonged lives due to being bound to transport proteins hydrophilic hormones- short life due to unbound (free) travelling

Question 25

Where are hormone receptors found?

Answer 25

the plasma membranes, on the mitochondria and other organelles, and in the nuclei of target cells

Question 26

What do steroids bind to?

Answer 26

nuclear receptors

Question 27

What do monoamines bind to?

Answer 27

receptors in nucleus, mitochondria, and ribosomes

Question 28

What do peptides bind to?

Answer 28

Plasma membrane receptors which activate second messengers (cAMP)

Question 29

What is enzyme amplification?

Answer 29

A very small hormonal stimulus can cause a very large metabolic effect

Question 30

What is Metabolic clearance rate (MCR)?

Answer 30

rate at which hormones are removed