Chapter 45: Hormones and the Endocrine System

Question 1

Define endocrine signaling

Answer 1

secreted molecules diffuse into the bloodstream and trigger responses in target cells anywhere in the body

Question 2

Define paracrine signaling

Answer 2

secreted molecules diffuse locally and trigger a response in neighboring cells

Question 3

Define autocrine signaling

Answer 3

secreted molecules diffuse locally and trigger a response in the cells that secreted

Question 4

Define synaptic signaling

Answer 4

NTs diffuse across synapses and trigger responses int arget tissues

Question 5

Define neuroendcorine signaling

Answer 5

neurohormones diffuse into the blood stream and trigger responses in target cells anywhere in the body

Question 6

What are local regulators?

Answer 6

molecules that act over short distances, reach target cells SOLELY by diffusion, and act on target within mili/seconds

Question 7

Prostaglandins are produced _____. They are a type of local regulator.

Answer 7

Throughout the body

Question 8

How does nitric oxide act as a local regulator?

Answer 8

NO is a gas.
When the level of oxygen in the blood falls, endothelial cells release NO, which diffuses into muscle cells and relaxes the cells. Vasodilation

Question 9

The three major chemical classes of hormones are __,____, and ____. Their solubility is ….

Answer 9

Polypeptides (water soluble/hydrophilic), steroids (lipid soluble/hydrophobic), and amines (both)

Question 10

Compare the location of receptor proteins in target cells for water-soluble hormones to lipid-soluble

Answer 10

water-soluble: secreted by exocytosis and travel freely in the bloodstream, bind to cell-surface receptors
lipid: diffuse via diffusion and bind to transport proteins. Diffuse into target cells and bind to receptors in the cytoplasm or nucleus.

Question 11

How do response mechanisms in target cells differ for
water-soluble and lipid-soluble hormones?

Answer 11

Water-soluble hormones, which cannot penetrate the plasma membrane,
bind to cell-surface receptors. This interaction triggers an intracellular signal
transduction pathway that ultimately alters the activity of a preexisting protein
in the cytoplasm and/or changes transcription of specific genes in the nucleus.
Steroid hormones are lipid-soluble and can cross the plasma membrane into the
cell interior, where they bind to receptors located in the cytosol or nucleus. The
hormone-receptor complex then functions directly as a transcription factor that
changes transcription of specific genes

Question 12

The thyroid is responsible for

Answer 12

stimulates and maintains metabolic processes
lowers blood calcium level

Question 13

The parathyroid is responsible for

Answer 13

Raises blood calcium level

Question 14

The adrenal medulla is a type of adrenal gland responsibel fro

Answer 14

epinephrine and norepinephrine

Question 15

The adrenal cortex is a type of adrenal gland responsible for

Answer 15

glucocorticoids (BGL)
mineralocorticoids reabsorb Na_ and excrete K+ in kidneys

Question 16

The ovaries are responsible for

Answer 16

secreting estrogen and progesterone

Question 17

The testes are responsible for

Answer 17

secretion of androgens

Question 18

The pineal gland is responsible for

Answer 18

production of melatonin

Question 19

The hypothalamus is responsible for

Answer 19

regulating the anterior pituitary
Hormones released from the posterior pituitary as well

Question 20

The posterior pituitary is responsible for

Answer 20

oxytocin
vasopression/ADH

Question 21

The anterior pituitary is responisble for

Answer 21

FSH/LH: stimulate gonads
thyroid stimulating hormone
Adrenocorticiotropic hormone
Prolactin
Growth hormone
MSH

Question 22

The pancreas is responsible for

Answer 22

insulin and glucagon

Question 23

Define a simple endocrine pathway

Answer 23

cells respond directly to a stimulus by secreting a hormone
Hormone travels through the bloodstream to target cells

Question 24

Define a simple neuroendocrine pathway

Answer 24

stimulus is received by a sensory neuron rather than endocrine tissue

Question 25

Negative feedback can be defined as

Answer 25

the response reduces the initial stimulus

Question 26

positive feedback can best be defined as

Answer 26

a stimulus is reinforced

Question 27

Compare the posterior and anterior pituitary

Answer 27

posterior: extension of the hypothalamus

anterior: an endocrine gland that synthesizes and secretes hormones in response to hypothalamus hormones

Question 28

Antidiuretic hormone, or vasopressin is responsible for…. and produced in the ____

Answer 28

responsible for regulating kidney function
produced in posterior pituitary

Question 29

Prolactin is responsible for …. and produced in ___

Answer 29

stimulates milk production
anterior pituitary hormones

Question 30

Growth hormone is secreted by ____ and responsible for

Answer 30

anterior pituitary
stimulates growth

Question 31

What are the roles of oxytocin and prolactin in regulating
the mammary glands?

Answer 31

Prolactin regulates milk production, and oxytocin regulates milk release.

Question 32

How do the two fused glands of the pituitary gland differ in
function?

Answer 32

The posterior pituitary, an extension of the hypothalamus that contains
the axons of neurosecretory cells, is the storage and release site for two neuro-
hormones, oxytocin and antidiuretic hormone (ADH). The anterior pituitary
contains endocrine cells that make at least six different hormones. Secretion of
anterior pituitary hormones is controlled by hypothalamic hormones that travel
via blood vessels to the anterior pituitary.

Question 33

Propose an explanation for why defects in a par-
ticular hormone cascade pathway observed in patients typi-
cally affect the final gland in the pathway rather than the
hypothalamus or pituitary

Answer 33

The hypothalamus and pituitary
glands function in many different endocrine pathways. Many defects in these
glands, such as those affecting growth or organization, would therefore disrupt
many hormone pathways. Only a very specific defect, such as a mutation affect-
ing a particular hormone receptor, would alter just one endocrine pathway. The
situation is quite different for the final gland in a pathway, such as the thyroid
gland. In this case, a wide range of defects that disrupt gland function would dis-
rupt only the one pathway or small set of pathways in which that gland functions

Question 34

When blood Ca2+ level galls below a set point, ___ glands release___ hormone

Answer 34

parathyroid glands
PTH

Question 35

How does PTH raise the level of blood Ca2+ in bones, kidneys, and intestines?

Answer 35

direct effects in bones and kidneys, indirect on intestines

bones: PTH causes matrix to break down
Kidneys: stimulates reabsorpition through renal tubules
Intestines: promotes production of vitamin D, which helps stimulate calcium in food

Question 36

If the blood Ca2+ level rises above the set point, the thyroid gland releases ____, which acts by…

Answer 36

calcitonin
inhibits bone breakdown and enhances Ca2+ excretion in kidneys

Question 37

List the effects of epinephrine and norepinephrine, as well as where they are produced

Answer 37

produced in adrenal medulla
glycogen broken down to glucose
increase BP, RPM, metabolic rate
change in blood flow patterns

Question 38

Describe the effect of minerlocorticoids and where they are produced

Answer 38

adrenal cortex

retention of sodium ions and water
increased blood volume and blood pressure

Question 39

Describe the effect of glucocorticoids and where they are produced

Answer 39

adrenal cortex

proteins and fats broken down and converted to glucose
suppression of immune system

Question 40

If a hormone pathway produces a transient response to
a stimulus, how would shortening the stimulus duration
affect the need for negative feedback?

Answer 40

. If the function of the pathway is to provide a transient response, a short-lived
stimulus would be less dependent on negative feedback

Question 41

Suppose you receive an injection of cortisone, a
glucocorticoid, in an inflamed joint. What aspect of gluco-
corticoid activity would you be exploiting? If a glucocorti-
coid pill were also effective at treating the inflammation,
why would it still be preferable to introduce the drug
locally?

Answer 41

You would be
exploiting the anti-inflammatory activity of glucocorticoids. Local injection
avoids the effects on glucose metabolism that would occur if glucocorticoids
were taken orally and transported throughout the body in the bloodstream.

Question 42

Which statement is accurate?
(A) Hormones that differ in effect reach their target cells by
different routes through the body.
(B) Pairs of hormones that have the same effect are said to
have antagonistic functions.
(C) Hormones are often regulated through feedback loops.
(D) Hormones of the same chemical class usually have the
same function

Answer 42

Hormones are often regulated through feedback loops.

Question 43

The hypothalamus
(A) synthesizes all of the hormones produced by the pituitary
gland.
(B) influences the function of only one lobe of the pituitary
gland.
(C) produces only inhibitory hormones.
(D) regulates both reproduction and body temperature.

Answer 43

regulates both reproduction and body temperature.

Question 44

Growth factors are local regulators that
(A) are produced by the anterior pituitary.
(B) are modified fatty acids that stimulate bone and cartilage
growth.
(C) are found on the surface of cancer cells and stimulate
abnormal cell division.
(D) bind to cell-surface receptors and stimulate growth and
development of target cells.

Answer 44

bind to cell-surface receptors and stimulate growth and
development of target cells.

Question 45

Which hormone is correctly paired with its action?
(A) oxytocin—stimulates uterine contractions during
childbirth
(B) thyroxine—inhibits metabolic processes
(C) ACTH—inhibits the release of glucocorticoids by the
adrenal cortex
(D) melatonin—raises blood calcium level

Answer 45

oxytocin—stimulates uterine contractions during
childbirth

Question 46

What do steroid and peptide hormones typically have in
common?
(A) their solubility in cell membranes
(B) their requirement for travel through the bloodstream
(C) the location of their receptors
(D) their reliance on signal transduction in the cell

Answer 46

their requirement for travel through the bloodstream

Question 47

Which of the following is the most likely explanation for
hypothyroidism in a patient whose iodine level is normal?
(A) greater production of T3 than of T4
(B) hyposecretion of TSH
(C) hypersecretion of MSH
(D) a decrease in the thyroid secretion of calcitonin

Answer 47

hyposecretion of TSH

Question 48

The relationship between the insect hormones ecdysteroid and
PTTH is an example of
(A) an interaction of the endocrine and nervous systems.
(B) homeostasis achieved by positive feedback.
(C) homeostasis maintained by antagonistic hormones.
(D) competitive inhibition of a hormone recepto

Answer 48

An interaction of the endocrine and nervous systems.