Chapter 5 - Exercise Physiology

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

hormones

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

False

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

liver

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

Upregulation

A condition where the concentration of a hormone is so high that all available receptors are bound to the hormone and any additional increase in hormone will have no additional effect is known as

saturation

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

neurotransmitters

The specific messenger RNA (mRNA) that is synthesized from the DNA carries the code to the _____ where the specific protein is synthesized.

cytoplasm

Identify the factors that influence hormone concentration in the plasma. (Select all that apply.)

Quantity of transport proteins
Rate of metabolism of the hormone

The G protein that acts as a link between the hormone-receptor interaction on the membrane surface and subsequent events inside the cell may open an ion channel to allow _____ to enter the cell

Ca2+

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

kidneys

Identify the enzyme that inactivates and converts cyclic AMP to 5' AMP

Phosphodiesterase

When a tissue is exposed to a chronically elevated level of a specific hormone, the receptors undergo _____, resulting in a diminished response for the same hormone concentration

down-regulation

Diacylglycerol is known to activate _____ that, in turn, activates other proteins in the cell.

protein kinase C

As receptors are specific to a particular hormone, any chemical similar in _____ will compete for the limited receptor sites on the target tissue

shape

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

pituitary

The steroid-receptor complex enters the _____ and binds to hormone-responsive elements which contain the instruction codes for protein synthesis

nucleus

Both lobes of the pituitary gland are under direct control of the _____

hypothalamus

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

G - Protein

The hormones move down the axon to blood vessels in the posterior hypothalamus where they are discharged into the

general circulation

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

Caffeine

Follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and growth hormone (GH) are hormones secreted by the

anterior pituitary gland

After the activation of phospholipase C, the calcium that is released binds to and activates a protein called _____, which alters cellular activity in a manner similar to cyclic AMP

calmodulin

Which of the following inhibits the release of growth hormone from the anterior pituitary

Hypothalamic somatostatin

The pituitary gland is attached to the

hypothalamus

How does the growth hormone spare glucose in the plasma? (Select all that apply.)

By increasing the mobilization of fatty acids from the adipose tissue
By opposing the action of insulin

The neurohypophysis of the pituitary gland is basically _____ that extends from the hypothalamus

neural tissue

True or false: Exercise is the most potent stimulus of growth hormone

True

Identify the function of the oxytocin hormone.

It is a powerful stimulator of smooth muscle at the time of child birth.

Which of the following directly stimulates the breast tissue to produce milk

prolactin

stimulates the release of the growth hormone from the anterior pituitary.

The growth hormone-releasing hormone

Thyroxine contains _____ iodine molecules

4

Which of the following is a function of the insulin-like growth factors (IGFs) and the growth hormone (GH)

Tissue uptake of amino acids

The parathyroid hormone increases Ca++ levels in the plasma by _____.

stimulating the bone to release Ca++ into the plasma

The levels of _____ in the blood exerts a negative effect on the continued secretion of growth hormone

insulin-like growth factor

The posterior pituitary hormones are produced in the

hypothalamus

Epinephrine and norepinephrine are catecholamines secreted by the _____

adrenal medulla

The iodine-containing hormones synthesized by the thyroid gland include

thyroxine and triiodothyronine

The adrenal medulla is part of the _____

sympathetic nervous system

Which is the primary hormone involved in plasma Ca++ regulation

Parathyroid hormone

True or false: Epinephrine and norepinephrine do not respond to strong emotional stimuli

False

Epinephrine and norepinephrine bind to _____ receptors

adrenergic

The posterior pituitary gland provides a storage site for ____

oxytocin and the antidiuretic hormone

The response generated in the target tissue by epinephrine and norepinephrine, both in size and direction, is chiefly dependent on ____

receptor type

adrenal cortex secretes

steroid hormones

Eighty percent of the adrenal medulla's hormonal secretion is _____, which affects receptors in the cardiovascular and respiratory systems, gastrointestinal tract, liver, and other endocrine glands

epinephrine

Epinephrine and norepinephrine are involved in the _____

maintenance of blood pressure and plasma glucose concentration

The two major classes of adrenergic receptors are ____

alpha and beta

Angiotensin II stimulates aldosterone release, which increases _____ reabsorption

Na+

The different receptors for the adrenal medulla hormones cause changes in the cell's activity by increasing or decreasing the _____ concentrations.

cyclic AMP

The primary glucocorticoid secreted by the adrenal cortex is ____

cortisol

Identify an example of a mineralocorticoid

Aldosterone

The _____ secretions of the pancreas include digestive enzymes and bicarbonate, which are secreted into ducts leading to the small intestine.

exocrine

Glucagon is secreted by the _____ cells in the islets of Langerhans

alpha

Testosterone is secreted by the _____ cells of the testes

interstial

Angiotensin II is a powerful ___

vasoconstrictor

Sperm production from the seminiferous tubules of the testes requires ___

the follicle-stimulating hormone

Cortisol contributes to the maintenance of plasma _____ during long-term fasting and exercise

glucose

Which of the following is both an exocrine as well as an endocrine gland

pancreas

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

Testosterone

Which of the following is required for sperm production in the seminiferous tubules

Testosterone

Because fuel substrate control is so biologically important, it is often regulated by

redundant mechanisms

At the onset of most types of exercise and for the entire duration of a very strenuous exercise, muscle _____ is the primary carbohydrate fuel for muscular work

glycogen

In the context of the processes through which the plasma glucose concentration is maintained in the body, identify the substrates for gluconeogenesis in the liver

Amino acids, lactate, and glycerol

Thyroid hormones allow other hormones to exert their full effect by

influencing the number of receptors on the target cell surface

True or false: T3and T4 are removed from the plasma by tissues during exercise at a slower rate than at rest.

false

During strenuous exercise, there is an obligatory demand for _____ oxidation that must be met in order to generate energy

carbohydrate

The intensity of exercise is directly related to the duration of exercise.

false

Which of the following processes help maintain the plasma glucose concentration in the human body? (Check all that apply.)

Mobilizing existing glucose from liver glycogen stores to maintain the plasma glucose level
Blocking glucose entry into cells to force the cell to use fat as a fuel, and thus sparing plasma glucose

The primary glucocorticoid in humans is __

cortisol

Thyroid hormones are important in establishing the overall

metabolic rate

During exercise, there is an increase in free T3 due to

changes in the binding characteristics of transport protein

Growth hormone plays a major role in the synthesis of tissue

protein

The primary catecholamine responsible for the mobilization of glucose from the liver and FFA from the adipose tissue is

epinephrine

Identify the functions of cortisol. (Select all that apply.)

It mobilizes tissue protein to yield amino acids for glucose synthesis.
It stimulates FFA mobilization from the adipose tissue.

Identify the hormone that seems to be more responsive than others to changes in plasma glucose concentrations.

Epinephrine

Elevated _____ drives the uptake and storage of glucose, amino acids, and fatty acids to lower their levels in the plasma

insulin

Growth hormone helps ___

increase free fatty acid mobilization

Which of the following is a function of epinephrine and norepinephrine

Interfering with the uptake of glucose by tissues

The high intramuscular _____ concentration that exists during exercise appears to recruit inactive glucose transporters so that more glucose is transported for the same insulin concentration.

Ca++

When the blood pressure is challenged, as during an increased heat load, the primary catecholamine involved is

norepinephrine

Elevated blood lactate has been linked to an increase in _____, a substrate required for triglyceride synthesis. This results in a reduced availability of plasma FFA

alpha-glycerol phosphate

Identify the true statements about the role of the hormones glucagon and insulin. (Check all that apply.)

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

True or false: Glucose transporters in a contracting muscle are also regulated by factors other than changes in calcium ion concentration such as protein kinase C and nitric oxide

True

High lactate levels have been associated with an elevated _____ concentration which, in turn, can inhibit hormone sensitive lipase. As a result, FFA are not released from the adipose cell.

H+

An increase in ______ levels decreases insulin secretion.

epinephrine and norepinephrine

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

False

Insulin binds to a ______ kinase receptor's alpha subunits, which reside outside the cell, in order to bring about its effects in a cell.

tyrosine

The parathyroid hormone stimulates the kidney to convert a form of ______ into a hormone that increases Ca++ absorption from the gastrointestinal tract.

vitamin D

The adrenal medulla is part of the

sympathetic nervous system

As the plasma Ca++ concentration increases, the release of ______ is increased to reduce the levels of plasma calcium. This constitutes a part of the negative feedback mechanism to control the secretion of the hormone

calcitonin

Angiotensin II is a powerful ______.

vasoconstrictor

The parathyroid hormone stimulates the kidney to convert a form of ______ into a hormone that increases Ca++ absorption from the gastrointestinal tract.

vitamin D

Cortisol promotes the breakdown of tissue protein to form ______, which are used by the liver to synthesize new glucose.

amino acids

Identify the functions of cortisol. (More than one option may be correct.)

It mobilizes tissue protein to yield amino acids for glucose synthesis.

It stimulates FFA mobilization from the adipose tissue.

Which of the following is a function of epinephrine and norepinephrine?

Interfering with the uptake of glucose by tissues

Free fatty acids could be trapped in the adipose cell as a result of rising blood Blank______ concentrations.
Multiple choice question.
myristate

lactate