Lecture 8

Question 1

Androgens and mineralocorticoids are secreted from where?

Answer 1

Adrenal medulla: catecholamines are also released from here, as well as epinephrine and norepinephrine..

Question 2

The medulla is similar in structure to what?

Answer 2

They ganglion.

Question 3

Consequences of thyroid hormone deficiency.

Answer 3

Physical growth and development problems, brain development is impaired. Cretinism: stunted physical and mental growth.

Question 4

Thyroid hormones T3 and T4.

Answer 4

T3 is the most powerful form; T4 tends to be converted into T3. Thyroid hormones need iodine.

Question 5

Goiter.

Answer 5

Lack of iodine causes the thyroid to enlarge. T3 and T4 are low in the case of low iodine intake; the hypothalamus releases TRH and causes the release of TSH in the anterior pituitary (TSH tells the thyroid gland to produce more T3 and T4). Note: in Goiter, T3 and T4 levels are low, but TRH and TSH levels are high.

Question 6

Grave’s disease.

Answer 6

Most common form of hyperthyroidism. Process: TIH acts as TSH to perpetually stimulate the thyroid gland, though the process is inhabited.

Question 7

Most peptide or protein hormones are hydrophilic or hydrophobic?

Answer 7

Hydrophilic.

Question 8

Steroids and hormones are lipophilic or lipophobic?

Answer 8

Lipophobic.

Question 9

Tropic hormones.

Answer 9

Target other endocrine glands and stimulate the growth and secretion of other hormones. Example: ACTH target the adrenal cortex.

Question 10

Sex hormones.

Answer 10

They target reproductive tissues.

Question 11

Anabolic hormones.

Answer 11

They stimulate anabolism (building) in target cells. Example: testosterone stimulates protein synthesis and build-up of cellular tissue. Insulin is also an anabolic hormone: leads to uptake and storage within the cell.

Question 12

Transportation of hydrophilic hormones.

Answer 12

They are dissolved in the plasma.

Question 13

Transportation of lipophilic hormones.

Answer 13

Bound reversible to plasma proteins.

Question 14

Hydrophilic peptide hormone synthesis.

Answer 14

Made on the ribosomes of the ER as preprohormones. They are sent tot he Golgi complex where they are turned into pro hormones and then active hormones. They re released from the endocrine cells by exocytosis.

Question 15

Which steroid hormone precursor is the only one that can be stored?

Answer 15

Cholesterol.

Question 16

Steroid hormones synthesis.

Answer 16

All are synthesized from cholesterol. They are lipid soluble, which means they can pass through membranes to enter the cell. They travel to the nucleus, bind to the receptor that has a zinc finger DNA binding domain, and binds at the hormone response element (HRE) to initiate gene transcription.

Question 17

Examples of steroid hormones.

Answer 17

Cortisol (adrenal), aldosterone (adrenal), estrogen (ovary and testes), progesterone (ovary-CL), and testosterone (testis, Leydig cells).

Question 18

Non-steroid hormone synthesis.

Answer 18

They are synthesized form amino acids

Question 19

HCG (human chorionic hormone) is an example of which class of hormones?

Answer 19

Glycoprotein hormone (protein hormone with carbohydrate groups attached).

Question 20

Non-steroid hormones.

Answer 20

Peptide hormones (example: oxytocin and antidiuretic hormone ADH), amino acid derived (synthesized by modifying a single molecule of tyrosine), amino acid hormones (derived from a single amino acid molecule), and T4 (thyroxin: tyrosine residues and 4 iodine molecules).

Question 21

Hormones, once they enter the cell, can…

Answer 21

Inactivate enzymes or cause initiation of gene transcription.

Question 22

Synergism of hormone action.

Answer 22

Hormones act together to have a greater effect on the target cell than the sum of the effects each would have if acting alone.

Question 23

Permissiveness in hormone action.

Answer 23

A small amount of one hormones permits or enables a second one to have its full effect on a target cell.

Question 24

Antagonism in hormone action.

Answer 24

One hormone produces the opposite effects of another hormone.

Question 25

What would happen if insulin action was extended?

Answer 25

When insulin is present, glucose is taken up by the cells. Extended insulin action would starve the brain of glucose.

Question 26

Hormone duration.

Answer 26

Hormones have a half-life; they are degraded in the liver and are then excreted.

Question 27

Is a cell’s response to steroid hormones fast or slow?

Answer 27

Slow, as transcription and protein synthesis dictated but the steroid hormone takes time, but the effects last longer.

Question 28

Catecholamines are which class of non-steroid hormones.

Answer 28

Amino acid derived.

Question 29

When in the cell, where to steroid hormones bind?

Answer 29

They bind to the hormone response element (HRE).

Question 30

Up-regulation of hormone sensitivity.

Answer 30

Increases the number of hormone receptors, thereby increasing sensitivity to the hormone.

Question 31

Down-regulation of hormone sensitivity.

Answer 31

Decreases the number of hormone receptors, thereby decreasing sensitivity.

Question 32

Sensitivity of a cell to a hormone depends on…

Answer 32

The number of receptors.

Question 33

Second messenger mechanism of hormone action.

Answer 33

The effects of the hormones are amplified by a cascade of reactions (effects can be disproportionately great) and it operates much more quickly than the steroid messenger system.