Male Reproductive System

____ produce male gamete and male sex hormones 

testicles (gonads) 

how many testicles (gonads) are there?

two (inguinal canal)

failure of one testicle (gonad) to descend is called ___

failure of both to descend is called ____

monorchid, cryptorchid

_____ produce testosterone but no sperm bull will mate, but usually will not settle a cow

retained testicles

an intact adult male HORSE is called ___

stallion

a castrated male HORSE is called ___

gelding

an intact adult male OX is called ___

bull

a castrated male OX is called ___

steer

an intact adult male PIG is called ___

boar

a castrated male PIG is called ___

barrow

an intact adult male SHEEP is called ___

ram

a castrated male SHEEP is called ___

wether 

an intact adult male GOAT is called ___

buck (billy)

a castrated male GOAT is called ___

Wether

an intact adult male CHICKEN is called ___

rooster

a castrated male CHICKEN is called ___

capon

Which species has pendulous testes?

ram and bull

Which species has non-pendulous testes? 

boar and stallion

pendulous versus non-pendulous testes is related to ____ (absent in stallion)

sigmoid flexure

the ___ is absent in stallions

sigmoid flexure

Irrespective of difference (pendulous or non-pendulous), the male repro tract has the same basic tubes and physiology… produce and deliver ___

spermatozoa

____ contains the testes 

scrotum

the scrotum regulates the ___ of the testes for sperm production

temperature

____ occurs at a temperature below core body temperature

spermatogenesis

____ is the smooth muscle layer that lies beneath the scrotal skin

tunica dartos muscle

(tunica dartos muscle) ____ detect temperature

sensory neurons

tunica dartos muscle pushes the testes closer toward the body for ___ or relaxes to ___ the testes away from the body 

warmth, cool

(tunica dartos muscle) ____ muscle allows for sustained contractions

smooth

____ also regulates the temperature of the testes for sperm production

spermatic cord

spermatogenesis occurs at a temperature ____

below core body temperature

____ is located along the spermatic cord and attaches to testis. Also helps regulate the temperature of testes

cremaster muscle

contraction of the cremaster muscle aids in ___ to the testis and increases/decreases cooling efficiency

blood flow 

____ counter-current heat exchange causes a cooling of arterial blood supply; single Artery surrounded by a network of veins (increased surface area) 

pampiniform plexus 

____ is on the surface of the testis and in rams the temperature decrease 4 CELSIUS before entering testis 

convoluted testicular artery 

scrotum, testis, and spermatic cord are all involved in ____

thermoregulation

**____ are the functional unit of the testis

seminiferous tubules

____ is the site of spermatogenesis

testis

(testis) tubules contain ___ (which nurse the developing spermatozoa)

Sertoli cells

(testis) interstitial space contains ___ (which produce testosterone)

Leydig cells

Leydig cells produce ___

testosterone

What are the phases of sperm?

spermatocyte → spermatids → spermatozoa 

testis delivers sperm to ____ which then drains into the efferent ducts 

rete testis 

testis delivers sperm to rete testis which then drains into the ___

efferent ducts

____ then coalesce into a single epididymal duct

efferent ducts

____ is a duct located on the outside of the testes and is composed of three parts (head, body, and tail) 

epididymis

What are the functions of the epididymis? 

concentrate sperm

store sperm

transport sperm

site of store maturation

epididymis is the site of sperm maturation; this process from the start of spermatogenesis to maturity takes ____ depending on species 

40-60 days

____ is a duct which connects epididymis to urethra of the penis 

ductus (vas) deferens

ductus (vas) deferens transports sperm at the time of ___

ejaculation

the ductus (vas) deferens is ___ to sterilize the male (vasectomy)

cut

vasectomy vs castration (google answer)

vasectomy = reversible, prevents ejaculation by cutting small piece of vas deferens

Castration = irreversible, removal of entire testicles

(male anatomy) picture of common urogenital system

a common urogenital system contains:

four accessory sex glands (ampullae, vesicular glands, prostate glands, and bulbourethral/Cowper’s gland)

the secretions from the four accessory sex glands of the common urogenital system constitute ___% of the volume of ejaculate 

50-90

(accessory sex glands - asg) ___ are glandular enlargements associated with the terminal parts of the ductus deferens 

ampullae 

the ampullae is well developed in the ___, ___, and ___, but is absent in the ___

stallion, bull, ram

boar

the ampulla adds ___ to ejaculate

volume

____ are paired glands that enter dorsocranial to the pelvic urethra 

vesicular glands (seminal vesicles) 

the vesicular glands (seminal vesicles) supply ___ for the sperm following ejaculation and deposition into the female reproductive tract

nutrients

the vesicular glands (seminal vesicles) include ____ (energy), ___ (buffers), and ____ that activate the sperm

carbohydrates, ions, enzymes 

the vesicular glands (seminal vesicles) contribute a large portion of ejaculate volume in ___ and ___

stallions and boars

What is the ejaculate volume and concentration rank of: rams?

0.5-2.0

1

What is the ejaculate volume and concentration rank of: bulls?

3-10

2

What is the ejaculate volume and concentration rank of: stallions?

40-100

3

What is the ejaculate volume and concentration rank of: boars? 

150-250

4

What is the ejaculate volume and concentration rank of: man?

2-6

5

____ is the organ of copulation

penis proper 

____ is the duct through the penis that carries sperm and urine 

urethra 

The ____ is a muscular organ characterized especially by its spongy, erectile tissue that fills with blood under considerable pressure during periods of sexual arousal

Penis Proper

____ is erectile tissue that fills with blood

corpora cavernosa 

____ contains dense collagenous tissue (firm when not erect; ruminants and swine)

fibroelastic penis type

____ blood sinusoids predominate over connective tissue, flaccid when not erect (stallion) 

musculocavernous penis 

____ is attached to the sacral vertebra and relaxes during sexual excitement

retractor penis muscle

____ is the terminal portion of the penis

glans penis

____ glans penis tapers to the end

bull

____ glans penis is filiform (tubular) appendage; helps deposit semen in the anterior vagina

ram

____ glans penis is spiral; deposits semen in the cervix

boar

____ glans penis has a bloated end; butts up against the cervix where semen is deposited 

stallion

____ is the sperm producing units of the testes and make up approximately 90% of the testes mass

seminiferous tubules 

Spermatogenesis occurs within the ____ of these long, coiled structures (seminiferous tubules) 

lumen

____ provide nourishment for the developing sperm located Within the seminiferous tubules which contain androgen-binding protein

Sertoli cells 

_____ produce testosterone and are located Between the seminiferous tubules 

Leydig or interstitial cells 

spermatocytogenesis is several ____ (non-reductional division)

mitotic cell divisions

What happens to chromosomes in meiotic cell divisions (reductional)? 

reduced from diploid to haploid 

What happens in the first meiotic cell division (reductional)? 

two identical diploid cells form

What happens in the second meiotic cell division (reductional)?

two identical haploid cells form (two contain Y chromo, two contain X chromo)

(sperm cell) ___ contains genetic material (chromatin) and enzymes (in the acrosome) necessary for fertilization 

head

(sperm cell) ___ attaches the head to the midpiece 

neck 

(sperm cell) ___ produces energy for the sperm

midpiece

___ propels sperm cell

tail

____ has more cylindrical sperm than bull, boar, or ram

Horse 

____ sperm head looks like an inverted egg or neckpiece

man

____ has bent or turned sperm

rat

____ has very straight, long and slender sperm

cock 

____ located within the brain is an integrator of most of the brain’s activities

hypothalamus

hypothalamus produces a peptide called ___ which controls the release of two hormones from the anterior pituitary gland called gonadotropin hormones (FSH and LH)

gonadotropin releasing hormone (GnRH)

hypothalamus produces a peptide called gonadotropin releasing hormone (GnRH) which controls the release of two hormones from the ____ called gonadotropin hormones (FSH and LH) 

anterior pituitary 

hypothalamus produces a peptide called gonadotropin releasing hormone (GnRH) which controls the release of two hormones from the anterior pituitary gland called ____

gonadotropin hormones (FSH and LH) 

stimulation by GnRH from the hypothalamus causes FSH and LH to be released from the anterior pituitary into the ___, which then go to the gonads where they stimulate specific functions 

blood 

stimulation by GnRH from the hypothalamus causes FSH and LH to be released from the anterior pituitary into the blood, which then go to the ____ where they stimulate specific functions 

gonads