KINE 2P09; LECTURE FIVE

Question 1

Hormone Structure and Synthesis

Answer 1

Amines
Peptides and proteins
Steroids

Question 2

Amine Hormones

Answer 2

Thyroid hormones (T3, T4)
Catecholamines (norepinephrine, epinephrine)
Produced in the adrenal medulla
Catecholamine (dopamine)
Produced in the hypothalamus

Question 3

Initially formed by ribosomes of the endocrine cells as large peptide known as _______, then cleaved by proteolytic enzymes into ______ and finally cleaved into ______

Answer 3

1. preprohormone
2. prohormones
3. hormones

Question 4

Steroid hormones

Answer 4

(do not dissolve in blood, need carrier proteins)
1. Cortisol
2. Aldosterone
3. Testosterone
4. Estradiol

Question 5

Hormone transport in blood must do…

Answer 5

1. Dissolve in plasma
2. Most peptides, all catecholamines
3. Must be bound to plasma proteins to circulate in blood

Question 6

Hormone metabolism and excretion

Answer 6

1. Performed mostly by liver and kidneys (hormones don’t stay in the blood forever)
2. T4 is converted to T3 inside target cell

Question 7

Mechanisms of hormone action

Answer 7

The ability of a cell to respond to a hormone depends upon the presence of specific receptors for that hormone on or in the target cell.

Question 8

An increase in the number of receptors for a hormone is called __________

Answer 8

up-regulation.

Question 9

A decrease in the number of receptors for a hormone is called ______

Answer 9

Down-regulation.

Question 10

Posterior pituitary does not contain _____ these hormones are released from hypothalamic neurons that project down to posterior pituitary

Answer 10

Glands

Question 11

intracellular receptors

Answer 11

• Lipid soluble hormone diffuses through the plasma membrane
• Binds to intracellular receptors in cytosol or nucleus
• Receptor binding affects altered rates of transcription of one or more genes
• Alters mRNA production and protein synthesis to evoke cell response
• Gene transcription can be increased to decrease

Question 12

Hormonal control by ions or nutrients

Answer 12

Ultimate hormonal function is to impose negative feedback on that ion/nutrient

Question 13

Hormonal control by neurons

Answer 13

Neural activity affects endocrine cell activity

Question 14

Hormonal control by other hormones

Answer 14

• The function of one hormone is only to stimulate or inhibit the secretion of the next hormone
• It also stimulates the growth of the gland (tropic hormone)

Question 15

Control of hypophysiotropic hormones

Answer 15

1. Neural
2. Hormonal feedback loops

Question 16

T3 stimulates ______ from the small intestine and increases fatty acid release from adipocytes

Answer 16

carbohydrate absorption

Question 17

________, which are a major source of ATP consumption in the body

Answer 17

T3 stimulates the activity of Na/K ATPases

Question 18

T3 is required for _______ from the anterior pituitary gland

Answer 18

normal production of growth hormone

Question 19

Common endocrine response to all stressors:

Answer 19

release of cortisol from adrenal cortex

Question 20

Major effects of growth hormone and IGF-1 include:

Answer 20

1. Bone growth (IGF-1 and growth hormone)
2. Protein synthesis, predominantly in muscle (growth hormone directly)

Question 21

Large deviations of extracellular calcium in either direction _______ can disrupt neurological and muscular activity

Answer 21

(too high or too low)

Question 22

Short feedback loop

Answer 22

The inhibitory impact of the anterior pituitary hormone on the upstream stage of the pathway