13.1

Question 1

endocrine system

Answer 1

• system of organs, cells, and tissues that secrete hormones
• connects using “blood highways”

Question 2

the endocrine system complements the

Answer 2

nervous system

Question 3

What essential functions does the endocrine system regulate?

Answer 3

• Smooth and cardiac muscle activity
• Metabolism
• Growth
• Reproduction
• Circadian rhythms

Question 4

What are endocrine glands?

Answer 4

Ductless glands that secrete hormones into interstitial fluid, which then diffuse into the bloodstream.

Question 5

what are hormones?

Answer 5

chemical messengers that are carried by the blood to distant target cells

Question 6

hormones are secreted by cell into

Answer 6

interstitial fluid

Question 7

hormones diffuse into the

Answer 7

bloodstream

Question 8

Name some examples of endocrine glands.

Answer 8

• Pituitary
• Thyroid
• Parathyroid
• Adrenal
• Pineal glands

Question 9

what is the role of hormone receptors?

Answer 9

• hormones affect only specific target cells
• hormones influence their target cells by binding to specific protein receptors leading to target cells producing a cellular response

Question 10

receptor expression levels can change

Answer 10

upregulated or downregulated

Question 11

What is the typical concentration range for circulating hormones?

Answer 11

Picomolar to nanomolar range.

Question 12

What happens during down-regulation of receptors?

Answer 12

Excess hormones decrease receptor numbers, making cells less sensitive.

Question 13

What happens during up-regulation of receptors?

Answer 13

hormone deficiency increases receptor numbers, making cells more sensitive

Question 14

chemical classes of hormones

Answer 14

lipid soluble and water soluble

Question 15

lipid soluble hormones include

Answer 15

steroid hormones and thyroid hormones

Question 16

steroid hormones

Answer 16

derived from cholesterol, contain 4 interconnected hydrocarbon rings

Question 17

List examples of steroid hormones.

Answer 17

• Aldosterone
• Cortisol
• Dehydroepiandrosterone
• Testosterone
• Estrogens
• Progesterone
• Calcitriol
  (All Cute Dinosaurs Take Epic Pictures Constantly)

Question 18

thyroid hormones

Answer 18

synthesized by attaching iodine to the amino acid tyrosine

Question 19

T3 and T4 are lipid soluble thyroid hormones because they contain

Answer 19

two hydrocarbon rings

Question 20

water soluble hormones include

Answer 20

amine hormones and peptide/protein hormones

Question 21

What characterizes water-soluble hormones?

Answer 21

they act on receptors at the cell surface and are the most abundant type of hormones in the body

Question 22

amine hormones are synthesized by

Answer 22

modifying certain amino acids

Question 23

two categories of amine hormones

Answer 23

catecholamines and melatonin

Question 24

catecholamine =

Answer 24

epinephrine, norepinephrine, and dopamine

Question 25

catecholamines are derived from

Answer 25

amino acid tyrosine

Question 26

melatonin is derived from

Answer 26

amino acid tryptophan

Question 27

peptide/protein hormones

Answer 27

- amino acid polymers - most hormones belong to this category

Question 28

most water-soluble hormones circulate through

Answer 28

the watery blood plasma in free form

Question 29

most lipid soluble hormones are not bound to

Answer 29

transport proteins because they are not soluble in blood (they are carried in blood via transport proteins)

Question 30

What is the free fraction of lipid-soluble hormones?

Answer 30

A small percentage (0.1%-10%) of lipid-soluble hormone molecules that are unbound and ready to diffuse out of capillaries.

Question 31

What is a general mechanism of hormone action?

Answer 31

Hormones bind to specific receptors in or on target cells, activating a signaling pathway.

Question 32

Where are plasma membrane receptors located?

Answer 32

On the surface of target cells.

Question 33

plasma membrane receptors are used by

Answer 33

water soluble hormones since they cannot cross the hydrophobic plasma membrane

Question 34

intracellular membrane receptors are used by

Answer 34

lipid soluble hormones, which pass through call membrane and bind receptors in the cytosol or nucleus

Question 35

G protein coupled receptors examples

Answer 35

- ADH (uses Gs, producing cAMP) - oxytocin (uses Gq, producing IP3/DAG and releasing Ca2+) - growth hormone inhibiting hormone (uses Gi)

Question 36

receptor tyrosine kinase examples

Answer 36

insulin and IGFs bind to receptor tyrosine kinases

Question 37

receptor guanylyl cyclases examples

Answer 37

ANP bind to receptor guanylyl cyclases

Question 38

Janus Kinase (JAK) coupled receptor examples

Answer 38

growth hormones, prolactin, erythropoietin bind to JAK

Question 39

a single hormone can act upon multiple target cels and a single target cell can respond to multiple different hormones, but

Answer 39

each receptor type is specific to a particular hormone

Question 40

permissive effect

Answer 40

required for another hormone to elicit a greater response in its target cell

Question 41

examples of permissive effect

Answer 41

- epinephrine and thyroid hormone control of lipolysis - TH increases # of beta-adrenergic receptors for EN

Question 42

synergistic effect

Answer 42

if the effect of the hormones acting together is greater than the sum of their individual effects

Question 43

examples of synergistic effect

Answer 43

glucagon and epinephrine control of blood glucose levels

Question 44

antagonistic effect

Answer 44

if the hormones effects have opposing actions

Question 45

examples of antagonistic effects

Answer 45

insulin and glucagon modulation of glycogen metabolism