Male reproductive System

testicles location in Mammals

Most mammals keep their testicles outside the body as the optimal temperature for speriogenesis is usually lower than the body temp

• some mammals like elphants, hippos or marine mammals have internal testes that use countercurrent heat exhcnage to regulate their temperature

Bull scrotum

a bilobed sac that houses the testicles and aids in their temperature regulation

Temperature changes causes the scrotum’s smooth muscles and fibroelastic tissue to contract or relax, adjusting the testis’s position

Testicle formation

formed inside the body, near the kidney, during embryonic life, and then they descend through the inguinal canal before or shortly after birth into the scrotum

• failure of proper descent results in cyprotorchidism

What is the gubernaculum

A connective tissue band that gudes the descent of testes into the scrotum

What are testes

Male gonads resposible for sperm and testosterone production

where does spermatogensis occur

specilized structures called seminiferous tublules within the testes

These tubulues converge into the rete testis, leading to the epididymis

Epididymis

Attached to the posterioir margin of each testis, consists of a head, a body and a tail

Reposnbile for storing maturing and transporting sperm

Testes + tunics

Testes are enveloped by tunics, providing support and protection

• Outermost layer: Tunica vaginalis, a serious membrane composed of viscreal and partietal layers

• Beneath tunica vaginalis, the tunica albuginea is a dense fibrous campsule surrounding the testis, maintaining its shape during spermatogenesis

Castration

Involves removing both testicles and can be done using open or closed techniques

Open castration

Involes incising the vaginal tunic for direct visualization, which is safer with larger blood vessels

Closed castration

Dosn’t open the vaginal tunic, reducing peritoneal cavity exposure but may increase bleeding risk

Spermatic cord

a structure that suspends and supports the testes within the scrotum. Consists of various componenets including

• vas deferends,

• blood vessels

• nerves

• lympahtic vessels

• cremaster muscle

The vas deferens

A muscular tube that propels and carries mature sperm from the epididymis to the urethra during ejaculation

Blood vessels within the spermatic cord

1. the testicular artery, supplying oxinated blood to the testes,

2. the pampiniform plexus, a network of veins that helps regulate testicular temperature

Cremaster muscle

Located within the spermatic cord, contracts or relaxes in repsonse to temeprature changes, adjusting the position of the testes within the scrotum for optimal temperature regulation

Assessory glands

Bulls have accessory genital glands that contribute to seminal fluid compostion and sperm viability

• incude: Prostate gland, seminal vesicles and bulbourethral glands

• Together the secretions from these glands form most of the seminal fluid, which aims in sperm transport, viability and fertilization

Seminal vesicles

Produce a fluid rich in fructose and other nutrients that provide energy for sperm motitlity

Prostate gland

located near the base of the urethra, secretes a fluid rich in enxymes and nutrients to nourish and protect sperm

Bulbourethral glands

AKA. Cowper’s glands

Secrete a clear fluid that lubricates the urethra and neutalizes acidity in the male and female reproductive tracts

Bull penis

is a fibroelastic penis meaning there is limited erectile tissue and the erection occurs without significant change in diameter

Which type of penis have a sigmoid flexure

Animals with a fibroelastic penis

The penis consisits of

Root: the base of the penis, atatched internally to the pelvic region

Body (shaft): the elongated portion of the penis, containing erectile tissue and blood vessels

Gland penis: the rounded, bulbous end of the penis, often more expanded than the shaft and highly sensititve to stimualtion

Prepuce (sheath)

Also know as the foreskin, the prepuce is afold of skin that covers and protects the glans penis when the penis is not erect. It can retract during erection to expose the free part of the penis

Sigmoid flexure

A curved S shaped portion near the base of the penis that straightens during erection. this anatomical feature aids in mating by allowing the penis to extend and penetrate the female reproductive tract effectively

Retrractor penis muscle

This muscle is reponsible for controlling the sigmoid flexure. During secual arosual the retractor penis muscle will relax and release the penis outside its sheath acheiving erection

Horse penis

have a musculocavernous penis that contains more erectile tissue and increase in diameter upon erection

Os penis (or baculum)

bone located within the erectile tissue of the penis. It varies in size, shape and structure among different species

• dogs, ferrets, raccoons

Spiked penis and bifurcated

Spike penis: tom cat

bifurcated: opossum

Phallus

Many male birds will have a copulatory organ called a phallus

Hemipenes

Some male reptiles have paired copulatory organs

Fish + internal fertilization

requires the males to have a modified anal fin “gonopodium” or a modified pelvic fin “claspers” (in sharks)

Phallus, hemipenes, gonopodiums and claspers

Not true penisies. They are jsut modifications to deliver the semen inside the female in animals that typically possess a cloaca

These structures will not contain a urethra