Homeostasis, Endocrine System, and Human Reproductive Cycles

Question 1

The extracellular component of G-protein coupled receptors is a ____.

Answer 1

ligand-binding site

Question 2

The intracellular component of G-protein coupled receptors is a ____.

Answer 2

portion that binds to G protein

Question 3

What happens when a G protein-coupled receptor is activated?

Answer 3

it associates with a G protein

Question 4

G protein-coupled receptors are able to transmit signals from ____ the cell –> ____ the cell.

Answer 4

outside –> inside

Question 5

G protein-coupled receptors initiate a long-term/short-term response.

Answer 5

short-term

Question 6

What are the four steps in the G protein-coupled receptor pathway?

Answer 6

1. receptor activation
2. signal amplification
3. cellular response
4. signal termination

Question 7

When the G protein is inactive, it is bound to ____

Answer 7

GDP

Question 8

When the G protein is active, it is bound to ____

Answer 8

GTP
releases GDP to bind GTP

Question 9

What subunit of the G protein binds to GTP?

Answer 9

alpha subunit

Question 10

What steps occur during signal amplification of the adrenaline pathway (after receptor activation)?

Answer 10

1. GTP-bound subunit binds to enzyme adenylyl cyclase
2. adenylyl cyclase converts ATP into cAMP
3. cAMP binds to and activates protein kinase A

Question 11

What is a second messenger?

Answer 11

a signaling molecule that relays info to the next target in the signal transduction pathway

Question 12

True or False:
A G protein-coupled pathway can only be terminated at the receptor.

Answer 12

False
can be terminated at either the receptor or G protein

Question 13

How is the G protein signal terminated at the receptor?

Answer 13

binding affinity of signaling molecule decreases, which leads to it dissociating from the receptor

Question 14

How is the G protein signal terminated at the G protein?

Answer 14

active GTP bound subunit turns itself off by converting GTP –> GDP

Question 15

What is homeostasis?

Answer 15

the active regulation and maintenance of a stable internal physiological state in the face of a changing external environment

Question 16

What are the four components of a negative feedback loop?

Answer 16

1. stimulus
2. sensor
3. effector
4. response

Question 17

What does a negative feedback loop do?

Answer 17

a process in which the output or produce of a pathway opposes the initial stimulus so that homeostasis is maintained

Question 18

What is the set point in a feedback loop?

Answer 18

a steady-state value in homeostatic regulation
i.e. temperature, levels of a chemical

Question 19

What is a hormone?

Answer 19

a chemical messenger that regulates the organism’s physiological response to the enviornment and helps maintain stable physiological conditions

Question 20

What are neurosecretory cells?

Answer 20

neurons in the hypothalamus and posterior pituitary gland that secrete hormones into the bloodstream

Question 21

What are neurohormones?

Answer 21

hormones released by neurosecretory cells

Question 22

What hormone is secreted in a negative feedback loop in which high blood glucose is the stimulus?

Answer 22

insulin

Question 23

What is the function of insulin?

Answer 23

body cells take up glucose and store it as glycogen

Question 24

What hormone is secreted in a negative feedback loop in which low blood glucose is the stimulus?

Answer 24

glucagon

Question 25

What is the function of glucagon?

Answer 25

stimulates the breakdown of glycogen into glucose

Question 26

What is the sensor in blood glucose loops?

Answer 26

pancreas

Question 27

What are the effectors in blood glucose loops?

Answer 27

* insulin/glucagon * body cells * muscle and liver

Question 28

What is a stimulus in a negative feedback loop?

Answer 28

a change in level from homeostatic set point

Question 29

What is the sensor in a negative feedback loop?

Answer 29

endocrine organ that detects a stimuli and initiates release of a signaling molecule

Question 30

What is the effector in a negative feedback loop?

Answer 30

a hormone/other bodily component that acts to exhibit a response

Question 31

What is the response in a negative feedback loop?

Answer 31

a response that opposes the initial stimulus and returns the body back to set point

Question 32

What happens in a positive feedback loop?

Answer 32

a stimulus causes a response in the same direction as the initial stimulus

Question 33

How does a positive feedback loop work?

Answer 33

more hormone is released, which escalates the response

Question 34

Where are the receptors of hydrophilic hormones located?

Answer 34

cell surface

Question 35

Where are the receptors of hydrophobic hormones located?

Answer 35

inside the cell

Question 36

What is the structure of peptide hormones?

Answer 36

short chain of amino acids

Question 37

What is the structure of amine hormones?

Answer 37

single aromatic amino acid

Question 38

What is the pituitary gland?

Answer 38

the central regulating gland of the endocrine system that releases hormones to coordinate the action of the other endocrine organs

Question 39

How does the anterior pituitary gland communicate with the hypothalamus?

Answer 39

neurosecretory cells in hypothalamus secrete hormones into blood vessels that travel to the anterior pituitary

Question 40

How does the posterior pituitary gland communicate with the hypothalamus?

Answer 40

communicates without the release of hormones neurosecretory cells extend axons into the posterior pituitary

Question 41

What are tropic hormones?

Answer 41

hormones that control the release of other hormones

Question 42

What is the difference between hormones and paracrine signals?

Answer 42

hormones enter circulation and target distant cells paracrine signals bind to receptors and target local cells

Question 43

What are pheromones?

Answer 43

water or airborne chemical compounds released by animals into the environment that signals and influences the behavior of other members of their spaces

Question 44

What are the gonads of the male reproductive system?

Answer 44

testes

Question 45

What gamete is produced in the male reproductive system?

Answer 45

sperm

Question 46

What sex hormones are involved in the male reproductive system?

Answer 46

testosterone and estrogen

Question 47

What are the target cells of the sex hormones in the male reproductive system?

Answer 47

Leydig cells and Sertoli cells

Question 48

What do Leydig cells do?

Answer 48

secrete testosterone and estrogen

Question 49

What do Sertoli cells do?

Answer 49

stimulate sperm production

Question 50

How are gametes released in the male reproductive system?

Answer 50

ejaculation

Question 51

What are the gonads in the female reproductive system?

Answer 51

ovaries

Question 52

What gametes are produced in the female reproductive system?

Answer 52

oocytes

Question 53

What sex hormones are involved in the female reproductive system?

Answer 53

estrogen, progesterone, and testosterone

Question 54

What are the target cells of sex hormones in the female reproductive system?

Answer 54

granulosa cells, hypothalamus, and anterior pituitary

Question 55

How are gametes released in the female reproductive system?

Answer 55

menstrual cycle (ovulation)

Question 56

What does GnRH do?

Answer 56

stimulates anterior pituitary to secrete LH and FSH

Question 57

How do GnRH levels change during the menstrual cycle?

Answer 57

follicular ↑ ovulation ↓ luteal ↓

Question 58

How do FSH levels change during the menstrual cycle?

Answer 58

follicular ↓ ovulation ↑ luteal ↓

Question 59

What does FSH do?

Answer 59

stimulates estrogen and progesterone secretion

Question 60

What does LH do?

Answer 60

stimulates the secretion of estrogen and progesterone

Question 61

How do LH levels change during the menstrual cycle?

Answer 61

follicular ↓ ovulation ↑↑↑ luteal ↓

Question 62

What does estradiol do?

Answer 62

acts on oocytes to begin to mature each month; causes the uterine lining to thicken

Question 63

How do estradiol levels change during the menstrual cycle?

Answer 63

follicular ↓ ovulation ↑ luteal ↓

Question 64

What does progesterone do?

Answer 64

helps maintain the thickened uterine lining in preparation for the possible implantation of a fertilized egg

Question 65

How do progesterone levels change during the menstrual cycle?

Answer 65

follicular ↓ ovulation ↓ luteal ↑

Question 66

What happens during the follicular phase?

Answer 66

stimulates the production of follicles on the ovary to mature into an egg

Question 67

What happens during the ovulation phase?

Answer 67

a mature egg is released from the ovary

Question 68

What happens during the luteal phase?

Answer 68

the uterus prepares for pregnancy by causing the uterine lining to thicken

Question 69

What happens during the menstruation phase?

Answer 69

the uterine lining sheds

Question 70

True or False: In certain situations, the body is able to change its set point.

Answer 70

True

Question 71

How is the set point changed when you have a fever?

Answer 71

pyrogens sense that your body is colder than it really is, so it sends a message to your brain to increase the set point, leading to you feeling hotter than normal

Question 72

When you are developing a fever and your body temperature set point increases, you may feel...

Answer 72

feel cold and shiver

Question 73

When your body is recovering from a fever, blood vessels in the skin dilate/constrict to release/retain heat. As a result, your skin appears ____.

Answer 73

dilate; release flushed

Question 74

When calcium levels are too high, the thyroid gland increases/decreases production of calcitonin.

Answer 74

increases

Question 75

What is the function of calcitonin?

Answer 75

deposits more calcium in the bone

Question 76

When blood calcium levels decline: Thyroid gland produces ____ to increase/decrease bone calcium levels.

Answer 76

calcitonin; increase

Question 77

When blood calcium levels rise: Parathyroid gland produces ____ to increase/decrease bone calcium levels.

Answer 77

PTH; decrease

Question 78

How are T3 and T4 produced?

Answer 78

thyroid takes in dietary iodide, which reacts with thyroglobulin to produce T3 and T4

Question 79

How do enlarged thyroids occur?

Answer 79

accumulation of thyroglobulin due to no dietary iodide intake, which prevents thyroglobulin from synthesizing to T3 and T4

Question 80

Feedback inhibition of GnRH ____ follicular development.

Answer 80

inhibits