Exam 1 - 18, 19, 20 and Exercise Physiology

Question 1

Endocrine system - General Information

Answer 1

Acts through release of hormones (mediator molecules); slower to respond, but longer lasting (when compared to the nervous system)

Question 2

Pineal Gland

Answer 2

Secretes melatonin (involved in setting biological clock)

Question 3

Pituitary Gland

Answer 3

Numerous hormones are secreted; tends to regulate other endocrine glands.

Question 4

Thyroid gland

Answer 4

T3 and T4 (two thyroid hormones); mostly involved with regulating basal (resting) metabolic rate.

Higher secretion of those hormones tends to result in higher resting metabolic rate.

Question 5

Parathyroid Gland

Answer 5

Very small, located on the posterior the thyroid; essentially regulating Ca++ concentration.

Question 6

Adrenal Glands

Answer 6

Releases catecholamines (norepinephrine and epinephrine), which are involved in increasing HR and the contractility of the heart.

Question 7

Down-Regulation

Answer 7

Causes a decrease in the number of receptors (often due to a surplus of a hormone).

Type II Diabetes: Too much insulin could lead to down-regulation, to decrease the number of receptors.

Question 8

Up-Regulation

Answer 8

A deficiency of a hormone can cause an increase in the number of receptors.

Type I Diabetes: Low levels of insulin; might try to increase (up-regulate) the number of receptors to get the same response.

Question 9

Local Hormones

Answer 9

Paracrine and Autocrine

Less common. Paracrine act on neighboring cells; Autocrine act on the same cell that released it.

Question 10

Nitric Oxide

Answer 10

A type of local hormone. Can be released to help to relax the smooth muscle or epithelial cell it was released from; or, help to target a neighboring cell, to vasodilate or vasoconstrict that neighboring cell.

Question 11

Lipid Soluble Hormones

Answer 11

Use transport proteins to be carried throughout the bloodstream.

Question 12

Free portion of lipid soluble hormones

Answer 12

The free portion of lipid-soluble hormones, the part that can circulate freely through the blood, can pass through the plasma membrane and target receptors on the inside of the cell or the inside of the cell directly.

Lipid soluble hormones = very little in ‘free’ form.

Question 13

Water Soluble Hormones

Answer 13

Amines, Peptides, and Eicosanoids.

Water soluble hormones circulate mostly in free form.

Question 14

Peptides

Answer 14

Peptides are water soluble hormones that are 3-49 amino acids in length.

Example: ADH (antidiuretic hormone)

Question 15

Water Soluble Hormones - proteins

Answer 15

Protein water soluble hormones are 50-200 amino acids in length.

Example: Insulin

Question 16

Mechanisms of Hormone Action

Answer 16

Lipid-soluble: bind to receptors on the inside of the cell (see previous note about free portion).

Water-soluble: binds to receptors on the plasma membrane, on the OUTSIDE/SURFACE of the cell; acts as a 1st messenger, activating second messenger (cAMP) on the inside of cell to amplify signal.

Question 17

Responsiveness of target cells

Answer 17

Depends on:

Concentration of hormone targeting that cell; number of receptors on that cell; and, other hormones - particularly, note hormones with antagonistic relationships.

Question 18

Antagonistic Hormone Relationships

Answer 18

Hormones which oppose the action of each other.

Example: Insulin and Glucagon. Glucagon is secreted to bring blood glucose up if it is low; insulin is secreted to lower blood glucose if it’s too high.

Question 19

The Pituitary Gland

Answer 19

Pituitary is attached to hypothalamus by the infundibulum. It has two parts:

the anterior pituitary (adenohypophysis)

and

the posterior pituitary (neurohypophysis)

Question 20

The anterior pituitary (adenohypophysis)

Answer 20

ADENO- means composed of epithelial tissue and it secretes hormones.

Anterior pituitary is the larger portion, about 75% of the pituitary by weight.

Question 21

the posterior pituitary (neurohypophysis)

Answer 21

NEURO- composed of neural tissues; it does not produce hormones (can store and release, but not produce, hormones).

Can store and release oxytocin and ADH in/from the posterior pituitary.

Question 22

Hormones of the Anterior Pituitary

Answer 22

Includes:

Prolactin (PRL), Adrenocorticotropic hormone (ACTH) or corticotropin, and Melanocyte-stimulating Hormone (MSH)

Question 23

Prolactin (PRL)

Answer 23

Anterior pituitary hormone.

Promotes milk secretion by mammary glands.

Works synergistically with estrogen, progesterone and oxytocin.

Question 24

Adrenocorticotropic hormone (ACTH) or corticotropin

Answer 24

An anterior pituitary hormone.

ACTH stimulates glucocorticoid (primarily, cortisol - ˜95% of all glucocorticoid action) secretion from the adrenal cortex (outer portion of the adrenal gland).

Question 25

Melanocyte-stimulating Hormone (MSH)

Answer 25

Unknown role in humans.