Ch 11

Question 1

Exocrine Glands

Answer 1

• secrete hormones into blood
• hormones carried to target cells, help regulate body metabolism, growth, and reproduction
• -> many organs secrete hormones

Question 2

Neurohormones

Answer 2

secreted by specialized cells of hypothalamus

Question 3

What are the chemical classifications of hormones?

Answer 3

amines
polypeptides/proteins
glycoproteins
steroids

Question 4

Amines

Answer 4

*hormones
derived from tyrosine and tryptophan
–>ex. hormones from adrenal medulla, thyroid, and pineal glands

Question 5

Polypeptides and Proteins

Answer 5

• hormones

- ->ex. antidiuretic hormone, insulin, and growth hormone

Question 6

Glycoproteins

Answer 6

*hormones
long polypeptides bound to a carbohydrate
–>ex. follicle-stimulating and luteinizing hormones

Question 7

Steroids

Answer 7

*hormones
lipids derived from cholesterol
-secreted by adrenal cortex and gonads
–>ex. testosterone, estradiol, progesterone, cortisol

Question 8

Synergistic Effects

Answer 8

Occur when two or more hormones work together to produce a particular effect

• may be additive (ex. epinephrine and norepinephrine each affect part in same way_
• may be complementary: when each hormone contributes a different piece of an overall outcome (ex. producing milk requires estrogen, prolactin, and oxytocin)

Question 9

Permissive Effects

Answer 9

Occur when one hormone makes the target cell more responsive to a second hormone

• ->exposure to estrogen makes the uterus more responsive to progesterone
• ->increase secretion of PTH makes the intestines more responsive to Vit D3 in calcium absorption

Question 10

Antagonistic Effects

Answer 10

Occur when hormones work in OPPOSITE directions

• insuilin and glucagon both affect adipose tissue
• ->insulin stimulates fat storage
• ->glucagon stimulates fat breakdown

Question 11

Hormone Action

Answer 11

Hormones bind to receptors on or in target cells

• binding is highly specific
• hormones bind to receptors with high affinity
• hormones bind to receptors with low capacity, saturating the receptors with hormone molecules
• Lipophilic hormone receptors are int he cytoplasm or nucleus
• water soluble hormone receptors are not he outer surface of the plasma membrane

Question 12

Nuclear Receptors

Answer 12

Lipophilic steroid hormones and thyroid hormone:

1. travel to target cells attached to carrier proteins
2. at target cell, dissociate from carrier protein and diffuse across plasma membrane
   - ->receptors are found within the nucleus and are called nuclear hormone receptors because they activate genetic transcription

• hormone receptors = transcription factors
• activated by bind of the hormone
• effect of these hormones therefore to produce new proteins, usually enzymes that change metabolism inside the cell

Question 13

Hormones: 2nd Messengers

Answer 13

• hormones that can NOT cross the plasma membrane bind to receptors on cell surface
• activate an intracellular mediator called 2nd messenger
• three major 2nd messenger mechanisms
  1. Adenylate Cyclase (activates a protein kinase)
  2. Phospholipase C (controls intracellular Ca)
  3. Tyrosine kinases

Question 14

Pituitary Gland

Answer 14

• attached to hypothalamus by infundibulum

- divided into anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)

Question 15

Anterior Pituitary

Answer 15

glandular epithelium with two parts - pars distills and pars tuberalis

Question 16

Posterior Pituitary

Answer 16

nervous tissue and also called pars nervosa

Question 17

Anterior Pituitary Hormones

Answer 17

Trophic hormones stimulate hormone secretion other glands:

• growth hormone (GH)
• Thyroid-stimulating hormone (TSH)
• Adrenocorticotropic hormone (ACTH)
• Follicle-stimulating hormone (FSH)
• Luteinizing hormone (LH): in the male, it is interstitial cell stimulating hormone (ICSH)
• Prolactin (PRL)

Question 18

Growth Hormone (GH)

Answer 18

*in most tissues

promotes protein synthesis and growth

Question 19

Thyroid-Stimulating Hormone (TSH)

Answer 19

*in thyroid gland

stimulates secretion of thyroid hormone

Question 20

Adrenocorticotrophic Hormone (ACTH)

Answer 20

*in adrenal cortex

stimulates secretion of glucocorticoids

Question 21

Follicle-Stimulating Hormone (FSH)

Answer 21

*in gonads

promotes gamete production and stimulates estrogen production in females

Question 22

Prolactin (PRL)

Answer 22

*in mammary glands

promotes milk production in lactating females

Question 23

Luteinizing Hormone (LH)

Answer 23

*in gonads

stimulates sex hormone secretion, ovulation and corpus lute formation in female and testosterone secretion in males

Question 24

Feedback Control of Anterior Pituitary

Answer 24

• final product regulates secretion of pituitary hormones (neg feedback inhibition)
• axis
• inhibition can occur at pituitary gland level: inhibiting response to hypothalamic hormones
• inhibition can occur at the hypothalamus level: inhibition secretion of releasing hormones

Question 25

Axis

Answer 25

relationship between hypothalamus, anterior pituitary, and the target tissue

Question 26

Posterior Pituitary Hormones

Answer 26

stores and releases two hormones mad win the hypothalamus 1. Antidiuretic Hormone (ADH) 2. Oxytocin

Question 27

Antidiuretic Hormone (ADH)

Answer 27

*posterior pituitary hormone | promotes retention of water in kidneys (also called arginine vasopressin, AVP)

Question 28

Oxytocin

Answer 28

*posterior pituitary hormone | stimulates contractions in childbirth and milk let-down in lactation

Question 29

Adrenal Glands

Answer 29

- found atop the kidneys | - consist of an outer adrenal cortex + inner adrenal medulla that function as separate glands

Question 30

Adrenal Medulla

Answer 30

neural tissue and secretes epinephrine and norepinephrine in response to sympathetic neural stimulation

Question 31

Adrenal Cortex

Answer 31

glandular epithelium and secretes steroid hormones in response to ACTH - three layers - secretes hormones made from cholesterol, called corticosteroids or corticoids - three categories

Question 32

Three layers of adrenal cortex

Answer 32

1. zona glomerulosa 2. zona fasciculata 3. zona reticularis

Question 33

What are the three categories of the adrenal cortex?

Answer 33

1. Mineralocorticoids: from the zone glomerulosa regulate Na+ and K+ balance. - ->Ex. aldosterone 2. Glucocorticoids: from the zone fasciculate regulate glucose metabolism. - ->Ex. cortisol 3. Adrenal androgens: from the zone reticular are weak sex hormones that supplement those made in the gonads.

Question 34

Cortisol (Hydrocortisone)

Answer 34

- stimulates protein degradation - stimulates gluconeogenesis and inhibits glucose utilization to raise blood glucose levels - stimulates liplysis

Question 35

Thyroid Gland

Answer 35

- located just below larynx | - has two lobes on either side of trachea, connected by isthmus

Question 36

Thyroid Gland Structure

Answer 36

- thyroid follicles: hollow spaces, lines w/simple cuboidal epithelium composed of follicular cells that produce thyroglobulin - interior of follicles is filled w/fluid called colloid - outside of the follicles are parafollicular cells that secrete calcitonin

Question 37

Production of Thyroid Hormone

Answer 37

-thyroglobulin is made by follicular cells -thyroid follicles actively accumulate iodide and secrete into the colloid • The iodine is attached to tyrosines within the thyroglobulin molecule. • One iodine produces monoiodotyrosine (MIT). • Two iodines produce diiodotyrosine (DIT). • Enzymes within the colloid attach MIT and DIT together: • DIT + DIT = T4 (tetraiodothyronine or thyroxine) • DIT + MIT = T3 (triiodothyronine) • These are still bound to thyroglobulin. • They dissociate from thyroglobulin when the thyroid gland is stimulated by TSH. • Secreted into the blood

Question 38

Thyroid Hormone

Answer 38

- T3 = active form, T4 can be converted to T23 by iodinates in cells - stimulates protein synthesis - promotes maturation of nervous system - increases rates of cellular respiration - elevates BMR

Question 39

Hypothyroid

Answer 39

``` impaired growth lethargy dry skin slow pulse constipation depression etc ```

Question 40

Hyperthyroid

Answer 40

``` accelerated growth increased activity excessive perspiration freq bowel movements rapid reflexes nervousness etc ```

Question 41

Parathyroid Glands

Answer 41

- generally four glands embedded in back of thyroid gland - secrete PTH - hormone promotes a rise in blood Ca b acting on bones, kidneys, and intestine

Question 42

Pancreas

Answer 42

both an endocrine and exocrine gland - endocrine cells are located in pancreatic islets (islets of langerhans) 1. alpha cells: glucagon 2. beta cells: insulin

Question 43

Insulin

Answer 43

- primary hormone regulation plasma glucose concentration - secreted by beta cells when blood glucose levels rise after sugary/carbohydrate meal - purpose to lower blood glucose to normal range - binds to receptors on target cells - indirectly stimulates the enzyme glycogen synthase in liver and skeletal muscles to promote sugar storage - stimulates adipose tissue to store fat

Question 44

Glucagon

Answer 44

- antagonistic to insulin - secreted by alpha cells when blood glucose levels are low - purpose is to raise blood glucose levels to normal range - stimulates liver to hydrolyze glucagon into glucose (glycogenolysis) and release it into the blood - stimulates gluconeogenesis: conversation of noncarbohydrate into glucose - stimulates lipolysis: in adipose tissue so fat is released and used as fuel source instead of glucose