Mod 12: Block theory

What is the main function of the male reproductive system

Produce and transport sperm

• sperm = male gamete cell

what is the general path of sperm

testes → duct system → outside of body

what are the main components of the male reproductive system

• testes

• scrotum

• duct system

• accessory glands

• penis

Describe Testes and its function

• 2 oval shaped organs (balls)

• produce spem

• develop the male reproductive system

What are the testes covered and protected by what?

2 tissues

• Tunica Vaginalis

  • outer covering

• Tunica Albuginea

  • inner fibrous coat/capsule

What do extensions of the tunica albuginea do and form?

• Extension penetrate into the testis

• divides it into Lobules (~250-300 compartments)

what do lobules contain

• up to 4 thin + elongated seminiferous tubules

what is found within the testes

tightly coiled seminiferous tubules

• each testis contain 600-1000 seminiferous in its lobules

what are seminiferous tubules function/ purpose

• sperm producing factories

what is found in the loose CT between seminiferous tubules

Leydig cells

• produce + secrete testosterone

Describe sperm

• gametes of male reproductive system

• carry paternal genetic info

• organized into 4 regions

4 regions of sperm

• head

• neck

• midpiece

• tail

what does the head of sperm contain

Nucleus

• X or Y chromosomes

What is the function of the acrosomal cap in the head of sperm

contains enzymes that help the sperm penetrate the egg

Purpose of neck of sperm

connects head to midpiece

midpiece of sperm

• continuation of neck

• has mitochondrial collar → helps produce energy

tail of sperm

helps sperm move

what is the scrotum

• sac of skin + fascia surrounding the testes

what is the scrotum derived from? and where does it reside

• derived from the anterior abdominal wall

• resides outside of the abdominopelvic cavity

muscles in the scrotum purpose

control the temperature of the testes

what are the two muscles in the scrotum

Dartos muscle

cremaster muscle

Purpose of dartos muscle

• wrinkly appearance of the scrotal sac

• helps regulate temperature by altering exposed SA of scrotum

Purpose of cremaster muscle

• reflexively contracts in a cold environment

  • draws closer to body so it can absorb heat

structures of the male duct system

• Epididymis

• Vas Deferens

• Urethra

note: each testes has their own duct system

Describe the epididymis

• first portion of the duct system

• lies on the superior + posterior border of each testes

describe each region of the epidiymis

• Head

  • contains + recieves sperm

• body

  • contains highly coiled duct

• tail

  • where sperm are stored prior to ejaculation

Purpose of the vas deferens

• stores + transports sperm from the epididymis to the urethra

What type of epithelium lines the vas deferens?

Pseudostratified columnar epithelium w/ stereocilia

What are key structural features of the vas deferens?

Small lumen + thick smooth muscle layer.

What is the function of the thick muscularis in the vas deferens?

Propels sperm forward (peristalsis).

what is the ampulla of vas deferens

the expanded distal portion of the vas deferens

what forms the ejaculation duct

ampulla of the vas deferens + duct of the seminal vesicle join to form the ejaculatory duct

what is the seminal vesicle + purpose

• accessory gland of the male reproducitve system

• sectetes nutritive fluid for sperm

what is the terminal portion of the male duct system

Urethra (learnt in mod 11)

• transports sperm out of the body

• also apart of urinary system

what are the 3 accessory glands that nourish the sperm as they travel through the duct system

• seminal vesicle

• prostate gland

• bulbouretrhal glands

Describe seminal vescile

• provide fluid + nutrients to the ejaculate

• make up 60% of voume of semen

Describe prostate gland purpose

• produces + secretes sugars and enzymes

• account for 33% of seminal fluid volume

Where is the prostate gland located and what is its size?

Below the bladder; about the size of a walnut.

what does the prostate gland consist of?

tubular glands embedded in a mass of smooth muscle + CT

Where are the bulbourethral glands located?

Below the prostate at the base of the penis

What do the bulbourethral glands secrete?

Thick, clear, alkaline mucus.

What is the function of bulbourethral gland secretion?

Neutralizes acidic urine and lubricates the urethra/penis before ejaculation

What is the pathway of sperm transport?

Epididymis → vas deferens → ejaculatory duct → urethra

What is added to sperm along its pathway?

Glandular secretions that form semen

penis functions

• urinary

• reproductive

Identify and describe the 3 parts of penis

1. root of penis

   1. attaches penis to ischium

2. body of penis

   1. moveable portion

   2. consists of 3 cylinders of erectile tissue

   3. contains the urethra

3. glans of penis

   1. distal end (tip)

   2. contains external urethral opening

the penis is made up of which 2 different types of erectile tissues? what do the two tissues create?

1. Corpora Cavernosa

2. Corpus Spongiosum

these two create 3 cyliners of tissue

What are the corpora cavernosa?

Two erectile cylinders on the dorsal penis that make up most of its mass.

What are the crura of the penis?

Proximal portions of the corpora cavernosa attached to the bony pelvis.

Which structure contains the urethra in the penis?

Corpus spongiosum.

What does the distal end of the corpus spongiosum form?

Glans penis.

What is the proximal enlargement of the corpus spongiosum called?

Bulb of the penis.

Vasectomy → how does it work?

• cutting of the vas deferens

• stops sperm from travelling from the epididymis to the urethra

• sperm can’t leave