Male Anatomy

What is the pathway sperm take (6)?

Testes, epididymis, ductus derferens, urethra, accessory sex glands, penis

What are the testes?

The male gonad, responsible for hormone and gamete (sperm) production, very fibrous

What pathway do sperm take within the testes (3)?

Seminiferous tubules, rete testes (mediastinum), efferent ducts

What are the 2 parts of the seminiferous tubules?

The tubular/adluminal compartment and the interstitial compartment/space

What are the seminiferous tubules?

The site of sperm production, continuously release spermatozoa (different sections are always at different stages of spermatogenesis to allow this to occur), sperm migrate from the outside of the tubules towards the inside as they mature

How long does it take for a sperm cell to mature?

~60 days

What is the tubular/adluminal compartment/space in the seminiferous tubules?

Contains sertoli cells and germ cells, supports spermatogenesis (FSH dependent), site of blood-testes barrier (protects germ cells from immune cells)

What is the interstitial compartment/space in the seminiferous tubules?

Contains leydig cells, blood vessels, lymphatic vessels, and immune cells, site of testosterone production (LH dependent)

What is spermiogenesis?

The differentiation of the spermatid

What are the 4 phases of spermiogenesis?

The golgi phase, cap phase, acrosomal phase, and the maturation phase

What is the golgi phase?

The initial cell, first phase

What is the cap phase?

The tail begins to develop and the acrosomal cap moves into position at head of sperm cell

What is the acrosomal phase?

Middle piece begins developing, acrosomal cap covers nucleus, residual bodies begin detaching

What is the maturation phase?

Middle piece fully develops, taily fully develops, residual bodies fully detach

What is the acrosome?

A lysosome containing enzymes required for penetration of the zona pellucida during fertilization

What is the epididymis?

A single tube 130-160 ft long, used for sperm transport and storage, site of full sperm maturation (where they reach fertilization and motility capacity)

What are the 3 sections of the epdidymis?

The head, body, and tail

What kind of sperm reside in the head of the epididymis?

Sperm here are NOT motile or fertile

What kind of sperm reside in the body of the epididymis?

Sperm here have minimal mobility and low fertility

What kind of sperm reside in the tail of the epididymis?

Sperm here have reached full motility and fertilization capacity, main site of sperm storage, increased sperm concentration

What is the spermatic cord?

Contains vascular, lymphatic, and nerves, containes the cremaster muslce and the vas deferens

Why is temperature regulation of the testes important?

It ensures the health of the sperm and enzymes

What are cryptorchids?

Animals with retained testes, often infertile because they are unable to regulate the temperature of the testes

What structures are mainly responsible for temperature regulation?

Pampiniform plexus,tunica dartos and cremaster muscles, and the scrotal skin

What is the pampiniform plexus?

A series of veins and arteries, help with temperature regulation through a countercurrent heat exchange system, always occuring

How do the tunica dartos and cremaster muscles help with temperature regulation?

The tunica dartos raises/lowers the testes in normal situations, the external cremaster muscle raises the testes in fight/flight situations (brings closer to body for protection), unconscious response

How does the scrotal skin help with temperature regulation?

It sweats to help with heat exchange

What are the accessory sex glands (4)?

Some animals may have all or only some, ampulla, prostate (all animals have), vesicular gland, bulbourethral gland

What is the purpose of the accessory sex glands?

To nourish and activate the sperm, clear the urethral track before ejaculation (urine is acidic and could damage the sperm), produces secretions to assist in the transport of sperm to the female reproductive tract

What is seminal plasma?

Secretions from the accessory sex glands and epididymis that helps boost sperm motility, provides an energy source for sperm (fructose), important for the delivery of sperm but not for fertility, makes up 95% of the ejaculated volume, mostly from seminal vesicles

What is a fibroelastic penis?

A penis with limited erectile tissue encased in non-expandable connective tissue, ruminants and swine

What is a musculocavernous penis?

A penis with large blood vessels that filll with blood during an erection, horse, dog, cat, and human

What is unique about a ram’s penis?

They have a urethral process extending out from the tip of the penis, its purpose is not understood

What happens when ruminats or swine get an “erection”?

They have a sigmoid flexure and retractor muscle that relax before copulation

What is unique about cat penises?

They have backwards facing spikes on the head, cause pain in the female when trying to pull out

What is unique about dog’s penises?

They have a bulbous gland that expands during copulation to “plug up” the female, can cause the male and female to stay stuck together for 5-45 mins