8. Endocrine System 4

Question 1

Describe the control of prolactin release

Answer 1

1. Secretion of prolactin by the anterior pituitary
2. Controlled by prolactin releasing hormone (PRH) and prolactin inhibiting hormone (PIH)
   (dopamine, a catecholamine) from the
   hypothalamus
3. Will secrete prolactin without PRH but PRH
   increases prolactin release during critical times
4. PIH has a braking effect on prolactin secretion when there is an excess of prolactin

Question 2

Describe the role of prolactin.

Answer 2

1. Promotes milk secretion
   - cytokine receptors on cell membrane
   - Stimulates the production of casein and other milk protein genes
   - increasing the transcription rate of mRNA for milk proteins
   -decreasing the degradation of mRNA for milk proteins

Question 3

What controls the rate of release of FSH and LH from the pituitary?

Answer 3

Gonadotropin-releasing hormone (GnRH).

Question 4

What is the effect of FSH in the male? (3)

Answer 4

1. attach to receptors on Sertoli cells in the seminiferous tubules
2. Stimulates sperm production
3. Stimulated Sertoli cells produce the hormone inhibin

Question 5

What is the effect of FSH in the female? (4)

Answer 5

1. growth of follicles
2. estrogen production from granulosa cells
3. increases FSH receptor numbers on granulosa cells
4. increases LH receptors on the granulosa cells of mature follicle

Question 6

What is the effect of LH in the male? (2)

Answer 6

1. stimulates leydig cells for their growth, development and function
2. Production of testosterone (steroid hormone)

Question 7

What is the effect of LH in females? (5)

Answer 7

1. works with FSH for follicle development
2. surge causes ovulation
3. lutenization of mature follicle cells
4. stimulates progesterone/testosterone production
5. formation of corpus luteum

Question 8

What is the role of the prostaglandins secreted by the seminal vesicles?

Answer 8

1. a component of the ejaculate
2. aids in fertilization in the female by:
   - reacting with the female cervical mucous to support sperm movement
   - contractions of uterus and oviduct to help movement of the sperm towards to ovaries

Question 9

Role of prostaglandin F2α in female?

Answer 9

1. from the uterus
2. causes CL degeneration
3. causes decreasing progesterone and ending the luteal phase of the cycle and to cause parturition
4. rapidly deactivated in lung and kidney

Question 10

What initiates the release of ADH and what are its actions?

Answer 10

1. increased extracellular fluid concentration, detected by osmoreceptors in or near the hypothalamus.

• ADH increases water reabsorption
• How? enhancing the permeability of collecting ducts and tubules in the kidneys,
• Result: conserving water and diluting the extracellular fluid.

Question 11

What factor other than increased osmolarity can increase the release of ADH?

Answer 11

decreased blood volume

Question 12

What is another name for ADH and why is the name appropriate?

Answer 12

Another name for ADH is vasopressin.

at higher concentrations, ADH constricts arterioles throughout the body, thereby increasing arterial pressure.

Question 13

List two factors that can stimulate the release of oxytocin and what the oxytocin causes to happen.

Answer 13

1. the stretching of the cervix and physical stimulation of the udder.
2. causes powerful contractions of the pregnant uterus
3. milk letdown: myoepithelial cells in the udder contract, constricting the alveoli and forcing milk into the ducts.