Reproductive System (male)

domestic animal anatomy & physiology

What are the functions of the male reproductive system?

• Detect females in estrus/heat

• Inseminate females

• Produce & maintain a supply of sperm

What is a gamete?

A mature reproductive sex cell that fuses with another gamete during sexual reproduction

What is a haploid?

Single, unpaired set of chromosomes

What does sperm contain?

Gamete & haploid

What is semen?

Sperm + seminal fluid

SEMEN & SPERM ARE NOT THE SAME THING

How do males detect females in estrus?

Visual cues, behavior cues, and chemical cues (pheromones)

What are the visual cues of a female in estrus?

• Vulva swelling

• Winking

What are the behavior cues of a female in estrus?

• Standing heat

• Mounting

How are pheromones detected by males?

Males lift up their upper lip (lip curling) so that the vomeronasal organ can detect pheromones.

What are the main structural classifications of penises found in mammals?

Fibroelastic & vasculature

What are the characteristics of the fibroelastic penis?

Contains more connective tissue & has less blood flow to region during erection; found in boars, bulls, rams

What are the characteristics of the vasculature penis?

Blood flow to the penis during erection; found in stallion, dogs, cats, humans

What is the function of the scrotum?

Epithelial tissue surrounding the testes; has blood supply & muscular components

What is the function of the testis/testes?

Production of sperm (spermatogenesis)

What is the function of the epididymis?

Sight of maturation of sperm & water absorption, storage of sperm

What is the function of the vas deferens?

Transport sperm from the epididymis to penis

What is the function of the prostate, seminal vesicles, & bullbourethral glands?

Produce seminal fluids that are secreted into vas deferens, where sperm turns into semen

What is the function of the sigmoid flexure?

It allows the long penile shaft to be folded up and completely stored inside of the animal's body when not in use

What is the function of the retractor?

When contracted, holds the penis in the body

When relaxed, allow the penis to extend outside the body

What is the function of the glans penis (GP)?

Detects temperature & pressure

What are sustentacular cells responsive to?

FSH & testosterone

What assists in the transportation of sperm out of the testes?

Muscle contractions & water absorption

What are interstitial endocrine cells responsive to?

LH

What is the function of testosterone?

development of second degree sex (male) characteristics, muscle development, libido (sex drive), maintain reproductive tract (accessory glands, penis, muscles used for ejaculation)

What is the function of the seminiferous tubule?

Cite of spermatogenesis

What is the function of the rete testis?

Where smaller tubules empty into larger tubules

What is the function of the efferent ductules?

Where smaller tubules empty into larger tubules

What is the function of the spermatic cord?

Connection between the testes & abdominal cavity, temperature regulation

Is the temperature of the testicles lower or higher than the temperature of the body?

Lower

In terms of temperature regulation, what is the function of the pampiniform plexus?

Counter current temperature exchange

In terms of temperature regulation, what is the function of the testicular artery?

Group of muscles (dartos & cremaster) which rise (cool) and lower (warm) the testes from body cavity depending on temperature

What is the function of the interstial endocrine cells?

Production of testosterone

What do sustantacular cells produce?

Androgen binding proteins, inhibin, & mullerion duct inhibiting substance

What is the function of androgen binding proteins which are produced by sustantacular cells?

Binds to testosterone, thus holding testosterone in testes

What is the function of inhibin which are produced by sustantacular cells?

Down regulate spermatogenesis, inhibitor for negative feedback loop

What is the function of mullerion duct inhibiting substance which are produced by sustantacular cells?

Prevents female internal reproductive organs from forming

What are the main regions of the sperm?

Head, mid piece, & tail

What are the parts of the head region of a sperm?

• Nucleus: where the DNA is

• Acrosome: stretched out organelle filled w/ enzymes that assist w/ injection of DNA into the oocyte

What is the main part of the mid piece region of a sperm?

Mitochondria: produce energy needed to get sperm to the oocyte

What is the main function of the tail region of a sperm?

Movement & locomotion

What is spermatogenesis?

The total process by which undifferentiated male germ cells transform into mature sperm cells

What is spermiogenesis?

The incomplete process by which haploid spermatids transform into mature sperm cells

What is the first step of maintaining sperm?

GnRH is released by the hypothalamus & signals the anterior pituitary gland

What is the second (a) step of maintaining sperm?

LH is released by the anterior pituitary gland which stimulates leydig cells to produce testosterone

What is the second (b) step of maintaining sperm?

FSH is released by the anterior pituitary gland which stimulates sertoil cells to produce androgen-binding proteins (ABP)

What is the third (a) step of maintaining sperm?

Testosterone helps stimulate & maintain sperm production

What is the third (b) step of maintain sperm?

ABP binds to testosterone & keeps testosterone concentrated in the seminiferous tubules

What is the fourth step of maintain sperm?

Testosterone & ABP work together to perform spermatogenesis

What down regulates spermatogenesis?

Inhibin & circulation of testosterone

How are gametes transported?

Via seminal vesicles, prostate, & bullbueurethral gland

How does seminal vesicles aid in the transport of gametes?

Production of viscous alkaline seminal fluid containing fructose, coagulated enzyme, & prostaglandins (cause reverse peristalsis); 70% of semen

How does prostate aid in the transport of gametes?

Production of milky slightly acid fluid containing citrate & enzymes which activate sperm

How does bullbueurethral gland aid in the transport of gametes?

Production of thick clear mucus pre-ejaculate which neutralizes acid from urine