Male Reproductive System

Purpose of the Male Reproductive Tract

-produce sperm cells and semen able to fertilize an egg

-transmit male genes to the offspring

-produce hormones such as testosterone

Components of the Male Reproductive Tract

-accessory sex glands

-spermatic cord

-testis

-excurrent duct system

-penis

Primary Sex Organs of the Male

testes

Secondary Sex Organs of the Male

-epididymis

-penis

Accessory Sex Organs of the Male

-seminal vesicles

-prostate

-bulbourethral gland

Cowper's Gland

other name for the bulbourethral gland

Os Penis

bony structure in the canine penile tissue

Bulbus Glandis

swells in and locks the male dog's penis into the females reproductive tract

Functions of the Scrotum

-protects and supports testes

-temperature regulation

4-6 degrees Celsius

How many degrees cooler than body temperature must the testicles be

Layers of the Scrotum

-skin

-tunica dartos

-scrotal fascia

-parietal vaginal tunic

Parietal Vaginal Tunic

Connective tissue sac around each testis

Scrotum Skin

-sweat glands

-regulated by hypothalamus

-responds to respiratory rate

-fat accumulation in scrotum

What happens when sperm get too hot?

decreased motility

Tunica Dartos

smooth muscle

-maintains contraction from the cremaster m.

-controlled by hormones (control level of testes)

Short Scrotum bulls

still produce sperm and hormones but sperm are not viable

-some can still breed

Other Reproductive Issues

low libido and short-shafted bulls

Cool Temperature Controls

testes will move up towards the body quicky when cooled quickly

Heat Temperature Controls

testes will lower and sweat in heat

Accessory Sex Glands

-ampulla

-vesicular glands

-prostate

-bulbourethral glands

Function of Accessory Sex Glands

responsible for secretion of seminal plasma

Function of Seminal Plasma

-plug female reproductive tract and minimize sperm loss

-extends sperm an allows for more motility

-boar and stallion have coagulative properties

When is Seminal Plasma most Important?

live cover

Ampulla

enlargement of the ductus deferens

Vesicular Glands

also called seminal vesicles

-contributes to a large portion of ejaculate in bulls and boars

Prostate Gland

a gland that contributes a small amount of seminal fluid to increase motility

Bulbourethral Glands

clear secretion prior to service

-flush and cleanse urethra of any urine residue

-acts as a coagulant in boar

Seminal Plasma

produced by epididymis (small amount) and accessory glands

-liquid noncellular portion

-mobility adds to the fertility of sperm

-delivery (natural service)

Spermatic Cord

provides pathway to and from the body

-testicular vascitulare, lymphaticsm, and nerves

Function of the Spermatic Cord

-testosterone distribution

-temperature control

-protection (cremaster)

-sperm transport

-provides vascularity, nutrients

Cremaster Muscle

striated muscle that supports testicles and controls temperature

-can pump blood

-no sustained contraction

Pampiniform Plexus

vessels intertwine with testicular artery

-countercurrent heat exchange

-testosterone exchange

34

What temperature is the blood in the testicular artery cooled too?

39

What temperature is the blood in the testicular veins warmed to?

False

T/F: The pampiniform plexus is a network of veins that cool the testis

False

T/F: There is only 1 pampiniform plexus

Location of the Cremaster Muscle

wrapped around the ductus deferens in the spermatic cord

Function of the Cremaster Muscle

aids in the control of temperature (lowering and raising) and protects the testicles in flight or fight response

False

T/F: The cremaster muscle and the tunica dartos muscle can both sustain contraction

4 Ways Temperature is Controlled for Testis

-sweat

-cremaster m.

-tunica dartos

-pampiniform plexus

Testes

sperm production and output (factory)

-located inside scrotum

-produce spermatozoa (spermatogenesis)

-produce testosterone

Structures Contributing to Temperature Regulation

-tunica dartos

-cremaster m.

-pampiniform plexus

Structure of the Testicles

-capsule

-parenchyma

-mediastinum

Tissues of the Testicle

parenchyma and mediastinum

Testicular Capsule

-visceral vaginal tunic

-tunica albuginea

Visceral Vaginal Tunic

peritoneum adheres to testes

Tunica Albuginea

dense white connective tissue covering the testis

Functions of the Testes Capsule

-houses rete tubules for fluid transport

-pumping action to facilitate sperm movement

Parenchyma

outer layer

major cellular mass of the testis

-seminiferous tubules (Sertoli cells)

Appearance of the Parenchyma

soft, tan mass of seminiferous tubules

-has lobes

Compartments of the Parenchyma

tubular compartment and interstitial compartment

Tubular Compartment of Parenchyma

seminiferous tubules and the cells and materials inside of them

-Sertoli cells

-seminiferous tubules

-seminiferous epithelium

-germ cells

-peritubular cells

Sertoli Cells

govern spermatogenesis

-support sperm production

-more Sertoli Cells=more sperm

Seminiferous Epithelium

basement membrane and lumen of seminiferous tubules

-consists of developing germ cells and Sertoli cells

Peritubular Cells

offer protection of sperm from immune system

-excludes immune cells and immunoglobulins from seminiferous tubules

Immune Response to Sperm

immune system attempts to destroy sperm because it identifies it as foreign (haploid cells)

-prevented by peritubular cells

Immune Cells and Immunoglobulins

macrophages, lymphocytes and antibodies

Location of Peritubular Cells

surrounding seminiferous tubules and Sertoli cell junction complex

Excurrent Duct System

moves spermatozoa out of the testicles.

-efferent ducts, epididymal ducts, ductus deferens

Efferent Ducts

moves new spermatozoa and tubular fluid into epididymal ducts

Ductus Deferens

carries sperm from the epididymis to pelvic urethra

-may take a longer/shorter time to arrive from epididymis depending on species

Epididymal Ducts

vary in length

-contract to move spermatozoa to the tail of the epididymis

2 weeks

Approximately how long does it take sperm to mature in the head and body of the epididymis?

Proximal Cytoplasmic Droplet

a cytoplasmic remnant from meiosis present on immature sperm cells

-located at the base of the head of the spermatozoa

-translocases into head of sperm

Distal Cytoplasmic Droplet

a remnant of cytoplasm that does not translocate, fertility is lowered

Epididymis

many tubules enter the head of the epididymis from testicle

-unit to for a single 130-160 inch tubule

-sections: caput, corpus, cauda

Functions of the Epididymis

-transport of developing sperm in testicles to vas deferens

-concentration of the sperm by absorption of surplus fluids

-maturation of the developing spermatozoa

-storage of viable sperm cells in the epididymal tail

Sections of Maturation

Caput and Corpus

Epididymis Cauda

location of storage

-mature (viable) sperm is stored until copulation/ejaculation

Excitation

spermatozoa stored in cauda travel via ductus deferens to urethra

-mix with seminal fluid from accessory sex glands

-ejaculate

Semen

seminal plasma + sperm

Root/Base of Penis

attached portion of the penis

Penile Shaft

main portion of the penis

-contains erectile tissue

-fills with blood to cause and erection

Horse

Which livestock species has the most erectile tissue?

Glans Penis

enlarged free end of the penis, richly supplied with nerves

Erectile Tissue of Penis

corpus cavernosum and corpus spongiosum

Corpus Cavernosum and Corpus Spongiosum

spongy erectile tissue in the shaft which fills with blood during an erection

Ischiocavernosus Muscle

strong muscles at the root of the penis that attach the shaft to ischial arch

Urethralis Muscle

surrounds pelvic urethra

-responsible for movement of seminal plasma and sperm through the pelvic urethra

Bulbospongiosus Muscle

empties the extra-pelvic part of the urethra

Species with Fibroelastic Penis

bull, boar, ram

Sigmoid Flexure

s-shaped bend in the penis

-retracted completely into the body

-when contracted-retains shape

Retractor Penis Muscle

contracted- penis in sheath

relaxed- penis exposed

Penile Spikes

present in cats

-function in inducing ovulation and holding penis in queen's vagina

Induced Ovulation by Stimulation

queens-penile spikes of tom or vaginal swabs can cause an ova to be released

Boar Sperm Deposition

Cervix (corkscrew)

Stallion Sperm Deposition

uterine body because of pressure during copulation

-large force during copulation

Bull/Ram Sperm Depoition

Fornix vagina

-cannot make it through the cervix

Filliform Appendage

a urethral process that allows the ram to "paint" the cervix of the ewe in semen

Interstitial Compartment of Parenchyma

leydig cells, blood vessels, connective tissue, lymphatics, and nerves

Leydig Cells

produce testosterone

Purpose of Interstitial Compartment

provides nutrients and maintains structures, preventing collapse of tubules

Parts of Seminiferous Tubule

tubulus contortus and rectus

Tubulus contortus

convoluted portion of the seminiferous tubules where spermatogenesis occurs

Rectus

straight portion of seminiferous tubules that connect tubulis controtus to rete tubules

Mediastinum

central area of the testicles

-houses rete tubules

-provides support so rete tubules do not collapse

Rete Tubules

tiny channels through which spermatazoa are transported out of the testicles into the efferent ducts

Androgen Binding protein

transports testosterone

-present within parenchyma

Sulfated Glycoprotein (SGP) 1 and 2

fertility acquisition and fluid movement

-present within parenchyma

Transferrin

iron transport required for spermatogenesis.

-present within parenchyma