Male Reproductive Physiology

Question 1

Sperm is made in what portion of the testes?

Answer 1

• Testis

Question 2

Where in the testis is sperm stored?

Answer 2

• Epididymis

Question 3

Cremasteric Reflex

Answer 3

• Stroking inner thigh and producing testicular elevation
• Lack of reflex suggestive of testicular torsion

Question 4

Testis Physiology

Answer 4

• Where sperm are made
• Almost 1,000 coiled seminiferous tubules

*ea. 0.5M in length

*sperm forming

Question 5

Epididymis

Answer 5

• Where sperm is stored
• 6M long
• Sperm travels from to vas deferens then ampulla of vas deferens and then to prostate gland

Question 6

Sperm Pathway

Answer 6

• Testis ⇒ Epididymis ⇒ Vas deferens ⇒ Ampulla of vas deferens ⇒ Prostate gland

Question 7

Seminal Vesicles

Answer 7

• Empty into prostatic end of ampulla
• Ampulla + seminal vesicle empty into the ejaculatory duct

*ejaculatory duct to prostate to internal uretrha

Question 8

Spermatogenesis in the embryo

Answer 8

• Primordial germ cells migrate to testis become spermatogonia (immature germ cells) in seminiferous tubules

Question 9

Sperm Mitotic Division

Answer 9

• Occurs after puberty (teen years)
• Meiosis
• Primary spermatocytes ⇒ secondary spermatocytes ⇒ Spermatids ⇒ Mature sperm (spermatozoae)

Question 10

Spermatogenesis Trigger

Answer 10

• Occurs during pubery until old age
• Stimulation of seminiferous tubules by anterior pituitary gonadotropic hormones

Question 11

FSH stimulates what in the male reproductive tract

Answer 11

• Sertoli cells

Question 12

Sertoli cells are stimulated by what hormone?

Answer 12

• FSH

Question 13

Luteinizing hormone stimulates what in the male reproductive tract

Answer 13

• Leydig cells to secrete testosterone

Question 14

What hormone stimulates Leydig cells to secrete testosterone?

Answer 14

• LH

Question 15

Migration of spermatogonia into the sertoli cell layer

Answer 15

• Sertoli cells: surround the spermatogonia
• Spermatogonia ⇒ primary spermatocytes ⇒ meiosis ⇒ secondary spermatocytes ⇒ spermatids ⇒ spermatozoa

Question 16

Spermatogonia to sperm timeframe

Answer 16

• 74 days

Question 17

Anatomy of Sperm

Answer 17

• Mature sperm contain hyalouronidase and proteolytic enzymes that allow it the sperms DNA to gain access into the ovum

Question 18

Sperm velocity/motility

Answer 18

• 1-4 mm/min
• Movement enhanced by an alkaline/neutral pH environment
• Acidic environment can cause sperm death
• Increased temp. increases sperm activity, can cause death due to increased metabolism

Question 19

Testosterones function in male reproductive physiology

Answer 19

• Secreted by Leydig cells upon stimulation from LH
• Enhance growth and division of germinal cells in testes

Question 20

Leydig Cells

Answer 20

• Present in newborn male infant for first few months
• Not present in childhood, but then are again present in adult male post puberty
• Secrete testosterone which enhances growth and division of germinal cells in testes
• LH from ant. pituitary stimulates

Question 21

Sertoli Cells

Answer 21

• Stimulated by FSH secreted from ant. pituitary
• Conversion of spermatids to sperm
• Estrogens: formed from testosterone by sertoli cells upon FSH stimulation
• Growth hormone stimulates metabolism and spermatogonial proliferation

Question 22

Sperm maturation from seminiferous tubules to epididymis

Answer 22

• During this time they are NON-MOTILE
• They become motile in the epididymis over the next 18-24hrs…capability of motility
• Inhibitory proteins are still present minimizing post ejaculatory motility

Question 23

Sperm capability of motility is inhibited by

Answer 23

• Inhibitory proteins

Question 24

Storage of sperm

Answer 24

• Stored in 2 testes = 120 million sperm formed daily
• Stored in suppressed state
• Post ejaculation sperm become MOTILE VIA MATURATION

Question 25

Sertoli cells and epithelium nutrient fluid

Answer 25

- Sertoli cells and epithelium secrete special nutrient fluid that is essential for maturation - Contains: \*testosterone \*estrogens \*enzymes \*nutrients

Question 26

Seminal vesicles secretions

Answer 26

- Contents are released into ejaculatory duct during emission - Fructose - Citric acid - Nutrients - Prostaglandins - Fibrinogen

Question 27

Prostaglandins role in male reproductivity

Answer 27

- Aid in fertilization - React w/ cervical mucous enhancing sperm movement - Causing reverse peristalsis of uterine tissue and fallopian tubes, thus enhancing sperm access towards ovaries

Question 28

Prostate gland function

Answer 28

Secretes: - Calcium - Citrate - Phosphate - Clotting enzyme - Profibrinolysis - Alkaline secretions (acid phosphatase)

Question 29

Semen Composition

Answer 29

- Fluid + sperm \*10% vas deferens \*60% seminal vesicles \*30% prostate \*trace from Cowper's gland (bulbourethral gland) - pH = 7.5

Question 30

Sperm Coagulum

Answer 30

- Holds secretions in place then dissolves in ~half an hour

Question 31

Capacitation of Spermatozoa

Answer 31

- Activating/preparing the sperm to penetrate the ovum

Question 32

Process of sperm maturaion in the female reproductive tract

Answer 32

- **Capacitation** - Sperm is deposited in the female reproductive tract - Inhibitory factors are removed by the female tract - Separation of **cholesterol** from the sperm **acrosome** \*acrosomal membrane weakens - Acrosomal increase in **calcium permeability** \***increased motion of sperm flagellum** - **Enzyme release from acrosome to begin fertilization/acrosome reaction** - Penetration of granulosa layer - Zona pellucida reaction \*Ca++ release from granules; block new sperm - Fertilization - Embryo w/ 46 chromosomes

Question 33

Where does sperm attach on the ovum?

Answer 33

- Granulosa cell layer

Question 34

What does the acrosome contain?

Answer 34

- Hyaluronidase and proteolytic enzymes

Question 35

What does the acrosome bind to?

Answer 35

- Zona pellucida \*initiates **zona pellucida reaction**; locking out of addtional spermatids

Question 36

Disease which affects seminiferous tubules

Answer 36

- Mumps

Question 37

Causes of abnormal sperm formation/infertility in males

Answer 37

- Diseases which affect seminiferous tubules \*mumps; causes tubules to swell causing ischemia in the area making sperm not form well - Excessive temp. of the testes

Question 38

Scrotal function

Answer 38

- Temp control for spermatogenesis - Keep seminiferous tubules 2 degress Celsius below body core temp. - Cremasteric reflex adjusts scrotal height

Question 39

Cryptorchidism

Answer 39

- Failure of a testicle to descend - Testes normally descend ~3-4wks before parturition - Testosterone from testis stimulates testicular descent - Failure of testicle to descend can lead to sterility, neoplasms (?)

Question 40

Sperm count per ejaculate

Answer 40

**- Volume of ejaculate ~3.5ml** **- 120 million sperm in 1.0 ml** - Range may normally vary from 35-200 million - Typical ejaculate is ~400 million **- \<20 million = infertility**

Question 41

Cryptorchidism hormonal treatment

Answer 41

- hCG

Question 42

Penis Glans nerve tract

Answer 42

- Pudendale nerve ⇔ sacral plexus ⇔ sacral spinal cord ⇔ brain

Question 43

Stages of penile erection

Answer 43

- Parasympathetics trigger - Arteriolar vasodilation - Venous outflow occlusion - Pressure in the corporae cavernosae - Nitric oxide/VIP/acetylcholine all aide in vasodilation

Question 44

Emission and Ejaculation Control

Answer 44

- Sympathetics T12-L2 - Hypogastric/pelvic sympathetics - The above produce emission...preparation of ejaculate - Ejaculation due to contraction of ischiocavernosus and bulbocavernosus muscles