Ch 5 Cell Signaling and the Hormonal Responses to Exercise

Question 1

The endocrine system differs from the nervous system in that it releases _____ into the blood to circulate to tissues.

enzymes
hormones
histamines
coagulation factors

Answer 1

hormones

Question 2

The effect of a hormone on a tissue is directly related to the _____.

rate of blood supply to the target tissue
hormone concentration in the plasma
mode of transport of the hormone
function of the target tissue

Answer 2

hormone concentration in the plasma

Question 3

An increase in _____ levels decreases insulin secretion.

Answer 3

epinephrine and norepinephrine (sympathetic nervous system activity)

Question 4

An increase in _____ levels increases insulin secretion.

Answer 4

plasma glucose and amino acids

Question 5

True or false: The magnitude of the excitatory input by itself determines whether there will be an increase or decrease in insulin secretion from the pancreas.

Answer 5

False; the magnitude of inhibitory vs excitatory input determines whether there will be an increase or decrease in the secretion of insulin

Question 6

The _____ can metabolize a variety of hormones or excrete them in their free (active) form.

Answer 6

kidneys

Question 7

Identify a hormone that is transported bound to a plasma protein.

Answer 7

Thyroxine (and steroid hormones) are transported, bound to a plasma protein

Question 8

Unlike the endocrine system, nerves use ___ to relay messages from one nerve to another

Answer 8

Nerves use NEUROTRANSMITTERS;
Endocrine system use hormones!

Question 9

True or false: The effect a hormone exerts on a tissue is independent of the number of active receptors to which it can bind.

Answer 9

FALSE; The effect a hormone exerts on a tissue is proportional (directly related) of the number of active receptors to which it can bind.

Question 10

Chronic exposure of a tissue to a low concentration of a hormone may lead to _____ of receptors, where the tissue becomes very responsive to the available hormone.

up-regulation
endocytosis
down-regulation
disaggregation

Answer 10

up-regulation

Question 11

Which of the following conditions increases insulin secretion from the pancreas?

Decrease in levels of omega-3 fatty acids
Decrease in blood pressure
Elevation of epinephrine and norepinephrine
Elevation of plasma glucose and amino acids

Answer 11

Elevation of plasma glucose and amino acids

Question 12

What is down-regulation?

Answer 12

Receptor number may decrease when exposed to a chronically elevated level of a hormone, resulting in a diminished hormonal response for a given concentration

Question 13

What is up-regulation?

Answer 13

Chronic exposure to a low concentration of a hormone which leads to an increase in receptor number with the tissue becoming very response to the available hormone

Question 14

What is saturation?

Answer 14

A situation in which the concentration of a hormone is so high that all receptors are bound to the hormone

Question 15

Inactivation of hormones can take place in the _____, the major site for hormone metabolism.

Answer 15

liver

Question 16

Steroid hormones easily diffuse through the cell membrane due to their __ nature and bind to a protein receptor in the cell cytoplasm to form the steroid-receptor complex

Answer 16

lipid-like

Question 17

A hormone must be in the _____ form in order to interact with the receptor and exert its effect on a cell.

free
lipid-bound
protein-bound
inhibited

Answer 17

free

Question 18

Many hormones exert their effects by binding to a receptor on the cell surface and activating a _____ located in the membrane of a cell.

Answer 18

G-Protein (the link between the hormone-receptor interaction on the surface of the membrane and the subsequent events inside the cell)

Question 19

_____ is known to increase phosphodiesterase activity by allowing cyclic AMP to exert its effect for a longer period.

Answer 19

caffeine

Question 20

What is a result of phospholipase C when it is activated by G PROTEIN?

Answer 20

Causes phosphatidylinositol (PIP2) to be broken down into inositol triphosphate (IP3) and diacylglycerol (DAG)

Question 21

Which of the following glands is located at the base of the brain?

Answer 21

pituitary gland

Question 22

What is the substrate for the formation of cyclic AMP?

GDP
GTP
AMP
ATP

Answer 22

ATP

Question 23

What is the enzyme that inactivates and converts cyclic AMP to 5’ AMP?

Answer 23

phosphodiesterase

Question 24

What hormone directly stimulates the breast tissue to produce milk?

Answer 24

prolactin

Question 25

_____ is a membrane-bound enzyme that is activated by a G protein and hydrolyzes phosphatidylinositol into two intracellular molecules. Phospholipase C Phosphodiesterase Protein kinase A Phosphorylase

Answer 25

phospholipase C

Question 26

Growth hormone (GH) and insulin-like growth (IGFs) stimulate the synthesis of new protein and long-bone growth

Answer 26

True

Question 27

What does insulin bind to, that resides outside the cell, in order to bring about its effects in a cell?

Answer 27

tyrosine kinase receptor's alpha subunits

Question 28

The posterior pituitary hormones are produced in the

Answer 28

hypothalamus

Question 29

Which hormone reduces water loss from the body?

Answer 29

antidiuretic hormone

Question 30

The hormones move down the axon to blood vessels in the posterior hypothalamus where they are discharged into the _____. general circulation pulmonary circulation primordial circulation intervillous circulation

Answer 30

general circulation

Question 31

What gland secretes the hormones follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and growth hormone (GH)?

Answer 31

anterior pituitary gland

Question 32

What are the two iodine-containing hormones synthesized by the thyroid gland?

Answer 32

triiodothyronine (T3) and thyroxine (T4)

Question 33

What are the functions of the growth hormone (GH) and insulin-like growth factors (IGFs)?

Answer 33

- stimulate tissue uptake of amino acids - synthesis of new protein - synthesis of long-borne growth

Question 34

What does the posterior pituitary gland provide a storage site for?

Answer 34

oxytocin and the antidiuretic hormone

Question 35

What is calcitonin?

Answer 35

Secreted by the thyroid gland, calcitonin is involved in a minor way in the regulation of plasma calcium ions

Question 36

What is the antidiuretic hormone?

Answer 36

it reduces water loss from the body; ADH favors the reabsorption of water from the kidney tubules back into the capillaries to MAINTAIN BODY FLUID

Question 37

What two major stimuli may cause an increase secretion of antidiuretic hormone (ADH)?

Answer 37

- high plasma osmolality (low water concentration) that can be caused by excessive sweating without water replacement - low plasma volume, which can be due to blood loss or to inadequate fluid replacement SUMMARY: high plasma concentration due to excessive sweating without drinking water AND low plasma volume which could be due to loss of blood

Question 38

How does calcitonin lower the levels of calcium in the plasma? by initiating the process of chondrogenesis by enhancing calcium reabsorption in the kidney tubules by increasing the production of activated vitamin D by blocking release of calcium from the bone

Answer 38

by blocking release of calcium from the bone NOTE: enhancing calcium reabsorption in the kidney tubules is the function of antidiuretic hormone

Question 39

What is the primary hormone involved in plasma Ca2+ regulation?

Answer 39

the parathyroid hormone

Question 40

How does the parathyroid hormone increase Ca2+ levels in the plasma?

Answer 40

by stimulating the bone to release Ca2+ into the plasma

Question 41

What is the primary stimulus for the release of thyroid hormones into circulation?

Answer 41

thyroid-stimulating hormone

Question 42

What secretes the catecholamines epinephrine and norepinephrine?

Answer 42

adrenal medulla NOTE: epinephrine and norepinephrine ARE catecholamines

Question 43

The adrenal medulla is part of what system?

Answer 43

the sympathetic nervous system

Question 44

What is the adrenal gland made up of (what glands make up the adrenal gland)?

Answer 44

the adrenal medulla (which secretes the catecholamines (epinephrine and norepinephrine)) and the adrenal cortex (which secretes steroid hormones)

Question 45

What does the adrenal cortex secrete compared to the adrenal medulla?

Answer 45

steroid hormones (contains aldosterone, cortisol, and sex steroids: androgens and estrogen) NOTE: adrenal medulla secretes epinephrine and norepinephrine

Question 46

Of the adrenal medulla's hormonal secretions, which one affects receptors in the cardiovascular and respiratory systems, GI tract, liver, and other endocrine glands?

Answer 46

epinephrine

Question 47

Renin converts angiotensinogen to angiotensin I, which is in turn converted to _____ by the angiotensin converting enzyme (ACE). angiotensin II angiotensin IV angiotensin III angiotensin V

Answer 47

angiotensin II

Question 48

What is the primary glucocorticoid secreted by the adrenal cortex?

Answer 48

cortisol

Question 49

Epinephrine and norepinephrine are involved in the _____. modulation and inhibition of action potentials in neurons release of digestive enzymes from the pancreas stimulation of red blood cell development in the bone marrow maintenance of blood pressure and plasma glucose concentration

Answer 49

maintenance of blood pressure and plasma glucose concentration

Question 50

What is an example of a mineralocorticoid; give its function

Answer 50

aldosterone: maintenance of Na and K concentrations in plasma

Question 51

Cortisol promotes the breakdown of tissue protein to form _____, which are used by the liver to synthesize new glucose. free fatty acids atrial natriuretic hormones amino acids glycerol

Answer 51

amino acids

Question 52

What is the General Adaptation Syndrome (GAS)?

Answer 52

The response when a stressful event (like burns, bone breaks, and heavy exercise) led to predictable increases in ACTH and cortisol

Question 53

What are the 3 stages of GAS (General Adaptation Syndrome)?

Answer 53

1) the alarm reaction (involves cortisol secretion) 2) the stage of resistance (where repairs are made) 3) the stage of exhaustion (repairs are not adequate and sickness or death results)

Question 54

Hormones are released from groups of cells in the endocrine portion of the pancreas called _____. Leydig cells the ascending limb of the loop of Henle the islets of Langerhans Sertoli cells

Answer 54

the islets of Langerhans

Question 55

Glucagon is secreted by the _____ cells in the islets of Langerhans. delta beta epsilon alpha

Answer 55

alpha

Question 56

How does cortisol contribute to the maintenance of plasma glucose during long-term fasting and exercise?

Answer 56

- by stimulating liver enzymes involved in the metabolic pathway leading to glucose synthesis - by stimulating the mobilization of free fatty acids from the adipose tissue - promote the breakdown of tissue protein (by inhibiting protein synthesis) to form amino acids which are then used by the liver to form new glucose (gluconeogenesis) - block the entry of glucose into tissues, forcing those tissues to use more fatty acids as fuel

Question 57

What secretions of the pancreas include digestive enzymes and bicarbonate, which are secreted into ducts leading to the small intestine?

Answer 57

exocrine

Question 58

_____ secretion is controlled by the interstitial cell stimulating hormone (ICSH) produced in the anterior pituitary. testosterone estrogen progesterone androstenedione

Answer 58

testosterone

Question 59

What is insulin's best-known function?

Answer 59

facilitated diffusion of glucose across the cell membrane

Question 60

Testosterone is an anabolic steroid because it stimulates? fatty acid breakdown glycogenesis lipogenesis protein synthesis

Answer 60

protein synthesis

Question 61

What is an anabolic steroid?

Answer 61

a prescription drug that has anabolic (GROWTH-STIMULATING) characteristics similar to that of the male androgen testosterone

Question 62

What secretion increases in response to low plasma glucose concentration?

Answer 62

glucagon

Question 63

What is the function of glucagon?

Answer 63

- stimulates the mobilization of glucose from liver stores (glycogenolysis) - stimulates free fatty acids from adipose tissue using the adenylate cyclase second messenger mechanism

Question 64

How is the plasma glucose concentration maintained? There are four processes, list them.

Answer 64

1) mobilize existing glucose from liver glycogen stores to maintain the plasma glucose level 2) mobilize plasma FFA from adipose tissue to increase the use of fat as a fuel and spare plasma glucose 3) synthesize new glucose in the liver (gluconeogenesis) from amino acids, lactate, and glycerol to have it available as needed 4) block glucose entry into cells to force the cell to use fat as a fuel, and thus spare plasma glucose

Question 65

Thyroid hormones allow other hormones to exert their full effect by _____. increasing ATP synthesis stimulating adenylate cyclase activity influencing the number of receptors on the target cell surface altering the structural conformation of other hormones

Answer 65

influencing the number of receptors on the target cell surface

Question 66

Growth hormone helps ___. increase glucose uptake by tissue increase free fatty acid mobilization decrease gluconeogenesis in the liver decrease glycogenolysis in the muscle tissue

Answer 66

increase free fatty acid mobilization

Question 67

What hormone seems to be more responsive than others to changes in plasma glucose concentrations?

Answer 67

epinephrine

Question 68

Thyroid hormones are important in establishing the overall _____. metabolic rate electrolyte balance pulse rate circadian rhythm

Answer 68

metabolic rate

Question 69

What is the function of epinephrine and norepinephrine?

Answer 69

- mobilization of glucose from the liver - mobilization of FFA from the adipose tissue - interference with the uptake of glucose by tissue

Question 70

What is the role of the hormones glucagon and insulin?

Answer 70

- often referred to as counter-regulatory hormones - insulin and glucagon exert opposite physiologic actions relative to the mobilization of liver glucose and adipose tissue FFA

Question 71

_____ causes a very rapid decrease in plasma epinephrine and norepinephrine responses to a fixed exercise bout. endurance training anaerobic exercises balance training strength exercises

Answer 71

endurance training