Male Physiology

Question 1

Describe capacitation of spermatozoa

Answer 1

Sperm at mature when they leave the epididymis but their activity is held in check by secretions from the genital duct epithelia
The changes that occur when they come in contact with the fluids of the female tract allow for capacitation of the sperm

Question 2

What changes occur during capacitation?

Answer 2

Uterine and Fallopian tubes wash away inhibitory factors
Loss of cholesterol that had built up on the acrosome which now make the head of the sperm weaker
Membrane of the sperm is much more permeable to Ca; increase the motility of the sperm

Question 3

A testosterone deficiency at 2nd-3rd month of gestation results in what?

Answer 3

Varying degrees of ambiguity in the male genitalia

Question 4

A testosterone deficiency during the 3rd trimester of pregnancy results in what?

Answer 4

Leads to problems in testicular descent (cryptochidism) along with micro penis

Question 5

A testosterone deficiency during puberty results in what?

Answer 5

Leads to poor secondary sexual development and overall eunochoid features
Enuchoidism: persistence of prepubertal characteristics and often by the presence of characteristics typical of the opposite sex

Question 6

A testosterone deficiency post-puberty results in what?

Answer 6

Leads to decreased libido, erectile dysfunction, decreased facial and body hair growth, low energy and infertility

Question 7

What are two syndromes associated with male hypogonadism?

Answer 7

Kallman’s syndrome and Klinefelter syndrome

Question 8

What is Kallman’s syndrome?

Answer 8

Genetic disorder that occurs when GnRH neurons fail to migrate into the hypothalamus during embryonic development
Characterized by delayed or absent puberty and an impaired sense of smell
Form of hypogonadotropic hypogonadism
Occurs more often in males

Question 9

What is Klinefelter syndrome (seminiferous tubular dysgenesis)?

Answer 9

Individuals with 47, XXY genotype
Individuals are phenotypically male because of the presence of the Y chromosome; appearance of male at birth
At puberty increased levels of gonadotropins fail to induce normal testicular growth and spermatogenesis
Androgen production is usually low whereas the levels of gonadotropins are elevated thereby indicating primary hypogonadism
Seminiferous tubules are largely destroyed resulting in infertility

Question 10

What is the effect and classification of Klinefelter’s syndrome?

Answer 10

Decreased testosterone with increased LH

Primary hypogonadism

Question 11

What is the effect and classification of Kallmann’s syndrome?

Answer 11

Decreased GnRH secretion
Tertiary/secondary hypogonadism
Decreased T with decreased or normal LH

Question 12

Describe hyperprolactinemia

Answer 12

Suppresses FSH and LH secretion due to prolactin’s negative feedback effect on the hypothalamus

Question 13

What is male pattern baldness?

Answer 13

Caused by DHT treated by 5a reductase inhibitor

Question 14

What is benign prostatic hypertrophy?

Answer 14

Treated with 5a-reductase inhibitor

Question 15

Describe prostate cancer

Answer 15

Treated with androgen receptor antagonist, radiotherapy and radical prostatectomy

Question 16

Tumors of testis (interstitial cell tumors) produce large amounts of what?

Answer 16

Testosterone

Question 17

Germinal epithelium tumors produce no what?

Answer 17

Hormones

Question 18

Describe andropause

Answer 18

As men age gonadal sensitivity to LH decreases and androgen production drops
As this occurs serum LH and FSH levels rise (FSH >LH)
Testosterone in aging in decrease slowly after age 40
Decreased bone formation, muscle mass, growth of facial hair, appetite and libido
Sperm production typically begins to decline after age 50 but many men can maintain reproductive function and spermatogenesis throughout life
Loss of sexual activity - typically about 68-70 years of age