Male Reproductive Anatomy

What are the Main parts of the Male reproductive tract?

What are the Main parts of the Male reproductive tract?

• Scrotum

• Testes

• Seminiferous Tubules

• Epididymis

• Vas Deferens

• Seminal Vesicles

• Prostate

• Bulbourethral Gland

• Penis

• Sheath

• Bladder

• Urethra

What are the Main functions of the Male reproductive Tract?

• Hormone production

  • Steroids

    • testosterone

  • Proteins

• Gamete production

  • Spermatogonia

  • Spermatozoa

• Gamete transport

  • Sperm

• Urination

  • Exits through the penile urethra.

• Ejaculation

What are considered the Major components of the the Male Reproductive Tract?

• Testis

  • Primary organ

• Epididymis

  • Located directly next to the testis

• Ductus deferens

  • Connect into the pelvic region

• Accessory glands

  • Seminal vesicles

  • Bulbourethral gland

  • Prostate gland

  • Preputial gland

• Penile urethra

• Penis and prepuce

What is the Primary Organ of the Male reproductive tract?

Testicles

Testicles must ___ to ensure normal function

descend into the scrotum

What is it called when the testicles fail to descend in males?

Cryptorchid

Where to Testes form?

Testes form near kidney at genital ridge

Descent into the scrotum caused by___

swelling of the gubernaculum

What is the time of Descent of the Testicles?

• Bull and ram, midterm gestation

• Boar, last quarter of gestation

• Stallion, just before or just after birth

  • More cryptorchids

The testicles must be ___ for sperm production

4-6° C cooler than body temperature

What are the side effects of males being cryptorchid?

In cryptorchids, since the testis are retained within the body they are infertile, because sperm production cannot occur due to too high of temperatures

What are the Structures that aid in thermoregulation of the testis?

• Scrotal skin

  • Has many sweat glands that allow for cooling of the testis

• Cremaster muscle

  • Located above the testis, closest to the body cavity.

  • Skeletal muscle that’s able to contract and relax in order to move testis closer or further away from the body

• Tunica dartos

  • Smooth muscle layer, that wraps around the scrotal pouch

  • Long term contraction

• Pampiniform plexus

  • Capillary network that is part of the spermatic cord that cools the testis

  • Veins wrap around the testicular artery in order to cool the blood going to the testis

What are the Main structures of the Testicles?

• Tunica albuginea

• Seminiferous tubules

• Rete testis

• Efferent ductules

Define Tunica albuginea

Outermost layer that allows the testis to slide back and forth in the scrotal pouch

Define Seminiferous tubules

Where sperm cells are produced

What are the Efferent ductules?

• Within the testis

• Helps get the sperm cells from the seminiferous tubules to the epididymis

What are the 2 main functions of the Testicles?

• Cytogenic

  • Production of gametes

    • Spermatozoa

• Endocrine

  • Secretes hormones

    • Steroid

    • Protein peptides

Parts of the Seminiferous Tubules

• Interstitial cells (Leydig)

• Basement membrane

• Primordial Germ Cells

• Sertoli cells

• Spermatozoa

What are the Interstitial Cells (Leydig Cells)?

• Produce Testosterone

• Outside the seminiferous tubules

• Next to the capillaries and blood vessels

What is the Basement Membrane?

• Basal lamina

• Surrounds the lumen

What are Primordial Germ Cells?

• Spermatogonium

• Very unique

• Stem cells throughout the whole life of the male

  • Undergo mitosis and replenish themselves (type A)

  • Can differentiate to continue developing into spermatozoa or die (type B)

• Spermatozoa

• Spermatocyte

  • Goes from diploid to haploid

  • They are genetically different from the body (body is diploid)

• Spermatid

  • Elongated spermatozoa

• Located alone the basement membrane in between the Sertoli cells.

What are Sertoli Cells?

• Nurture germ cells through development

• Produce numerous steroids

• Has their own nucleus

• aids in spermatogenesis

• tight junctions in between cells where differentiation takes place

• system within the seminiferous tubules that is immune privileges (no immune cells)

• blood testis barrier keeps immune cells from entering the lumen, so that the immune cells do not kill off the haploid sperm cells

Where do Spermatozoa go within the Seminiferous Tubules?

• Released into lumen

• Connects to Rete Testis

• Efarnic ducts then connects the rete testis and epididymis

What 3 parts make up the Epididymis?

• Caput = Head

• Corpus = Body

• Cauda = Tail

What are the Characteristics of the the Caput?

• Absorption to concentrate sperm

• Transport

• Cytoplasmic droplet is formed in the elongated sperm cells

  • Binds to the midpiece of tail and prevents cell from moving

What are the Characteristics of the Corpus?

• Secretions ‘mature’ sperm

• Remove cytoplasmic droplet

• Forward/progressive motility

• Fertility

• Sperm cells gain motility and fertility, by the loss of the cytoplasmic droplet

What are the Characteristics of the Cauda?

• Storage for ejaculation

  • Sperm cells are stored here

• Continues to flow cells through whether ejaculation occurs or not

  • Can sometimes find sperm cells in urine

Define Vas deferens (Ductus Deferens)

• Continuation of the cauda epididymis

  • Continues into spermatic cord

Where do the Vas Deferens enter the pelvic urethra?

Enters the pelvic urethra just posterior to bladder

What is the thickening of the vas deferens called?

• The ampulla

  • Happens right before the vas deferens enter the pelvic urethra

What are the functions of the Vas deferens (ductus deferens)?

• contractile tube for sperm transport

• longitudinal and circular muscular layers

Which species is the Muscular Ampulla present in?

Bull, Ram, and Stallion

The ampulla is absent in what species?

Boar

what are the characteristics of the ampulla?

• Little volume

• Muscle contractions

  • More muscle tone due to thickening

What is a “false mount”?

• “false mounts” increases contractions and results in more sperm/ejaculate

• Remove male from sexual stimulus, before ejaculation can occur

  • Increase ejaculatory load by almost 60%

what do the accessory glands of the the male reproductive tract do?

helps secrete fluids of the seminal plasma

What are the accessory glands of the the male reproductive tract?

• Seminal vesicles

• Prostate gland

• Bulbourethral gland

  • Cowper’s Gland

What are the seminal vesicles?

• Lobulated Vesicular glands

• Paired in most species

What is the function of the seminal vesicles?

• Production of seminal fluid

• Sperm viability

• Flushes tract

  • Helps flush out the urethra, hep reduce infection and debris

the seminal vesicles produce:___

• Fructose

• Citric acid

• Inositol

• Helps balance the pH of the system

Species variations in the seminal vesicles:___

• Boar = little fructose, more inositol

• Stallion = no fructose

• Humans = coagulating fraction

• Volume varies (total and percent)

Characteristics of the Prostate:

• Body and/or disseminate

• Small in bull and ram

• Large in boar

• 2 lobes in stallion

What is the prostate responsible for?

provides components to the seminal plasma

What does the prostate produce?

• Prostate specific antigens

  • Can be early detector of prostate cancer

• Other proteins

Bulbo-urethral gland is also called the ___

Cowpers Gland

What is the role of the Bulbo-urethral gland?

• Produce large gelatinous fraction (boar)

  • Unique to boars

• Last component of ejaculation

• Provides physical barricade in the cervix of the female in order to keep semen in female

What are the 2 types of Penises?

• Vascular

• Fibroelastic

What are the Characteristics of a Vascular Penis?

• No Sigmond Flexure

  • S shaped structure

• Penis fills with blood

  • Enables erection

  • ↑ Blood pressure

  • Enables erection

• Humans and Stallions

What are the Characteristics of a Fibroelastic Penis?

• Rigid in non-erect state

  • ‘S’ shape due to Sigmond Flexure

• ↑ Blood pressure = straightens

  • Also increase in blood flow

• Has a retractor penis muscle relaxes during erection

• Bulls, Rams, Boars

Parts of the Penile Shaft are,___

• Corpus Cavernosum (CC), Corpus Spongiosum (CS)

  • Contains small cavernosal arteries

• Releases nitric oxide that does not allow the blood to leave the arteries in able to keep erection

What are the major parts that make up the Penis?

• Penis retractor muscle (helps hold fibroelastic penis in place) and Sigmoid Flexus

• Cavernous tissue surrounding urethra

• pelvic urethra

• penile urethra

• Ischiocavernous Muscles

• Bulbospongiosus Muscles

• The glans penis is richly supplied with nerves and is the source of the sensations associated with copulation

which penile shape is associated to which animals?

• A-is Dogfish

• B and G-have a duplex uterus in the female counterpart, B is American Possum, and G is another marsupial

• C- is a Ram, the small piece is the filiform appendage

• D- is a Bull

• E- is a Shrew, a type of Rodent, shape is to distribute the semen throughout the cervix

• F- is Man

What are the master regulators of reproduction?

Hypothalamus and pituitary Gland

Overview of Male Reproductive Anatomy:

• Primary Organ

  • Testis

    • Produce sperm cells

• Secondary Organs

  • Epididymis

  • Vas deferens

    • Carries sperm cells up into the body cavity and to the penile urethra

  • Penis shaft

  • Glans Penis