The male Reproductive Systems

What is sexual reproduction?

When gametes from two parents form a zygote

What are gametes

sex cells

• sperm

• ovum

Sperm

mobile sex cells from the male

ovum

nutrient rich sex cells from the female

What are the primary sex organs

Gonads

• organs that produce gametes (sex cell)

In males

• sperm is produced in the testes

In females

• eggs (ova)/ovum are produced in ovaries

Secondary sex organs

do not produce gametes, but they are necessary for the process of reproduction

Males—

• storage or transfer of sperm

  • through ducts, glands, and the penis

Females—

• transport ovum and support the egg during development

  • uterine tubes, uterus, and vagina

Where are both the male and female external genitalia found

• located in the perineum, which is bound by the pubic symphysis, ischial tuberosity

• periuneum is a diamond shaped structure

Urogenital triangle v anal triangle

• the urogenital triangle is from the site of the pubic symphisis (below the penis) to right above the anus

• the anal triangle is a triangle around the anus

Where are the testes

• located in the scrotum

• the testes are separated by an internal median septum that divides them into left and right

Perineal raphe

• a visible ridge or seam of tissue running down the midline of the perineum (the area between the genitals and anus)

• in both males and females, representing the fusion point of embryonic structures

The left testes

• the left testicle typically hangs lower than the right in most men

Spermatic cord

• tube or connective tissue and muscle

• a bundle of blood vessels, nerves, and the vas deferens

• the spermatic cord passes upward behind and superiorly to the testis, where it then passes via the inguinal canal

Testis temperature regulation

• testicles actively regulate their own temperature, needing to stay cooler than core body temp for healthy sperm production,

  • using muscles to move them closer or farther from the body, specialized blood flow (countercurrent exchange), sweating, and skin properties like thinness and hairlessness to dissipate heat when hot, or keep them warm when cold.

• the muscles used to help regulate temperature are

  • cremaster muscle

  • dartos muscle

  • pampiniform plexus

Cremaster muscle

• contracts and draws the testes closer to the body to keep them warm

Dartos muscle

• also contracts when cold, making the scrotum taut and wrinkled

• holds it against the body

Pampinform plexus

• prevents warm arterial blood from overheating the testes

Inguinal canal

• weak point in the body wall; excessive force can lead to an inguinal hernia— which is penetration of organs into canal and even into the spermatic cord

The testicles

• produce hormones and sperm

  • exocrine and endocrine

• the testicles are divided into lobules, where each lobule contains 1-3 seminiferious tubules— these are the ducts in which sperm are producded

Seminiferous tubules

• are highly coiled tubes inside the testes where sperm (spermatozoa) are produced

• they are lined with germinal epithelium

  • germ cells—produce sperm

  • sustentacular (Sertoli) cells—sustain germ cells

Rete testis

• where sperm goes as it further develops

• a complex network of tiny, interconnected tubules located within the testicles that collects sperm from the seminiferous tubules and transports it to the epididymis through efferent ductules

Epididymis

• where sperm finish developing

• maturation takes about 20 days

Interstitial cells

• found between tubules and produce testosterone boys

Spermatozoom

• head

  • has the nucleus, which holds the genetic material

  • has the acrosome— cap covering the nucleus and contains enzymes

  • has the flagellar basal body— connects the tail to the head

• tail

  • midpiece—contains the mitochondria

  • has the principal piece

  • endpiece

The spermatic ducts

After leaving the testis, the sperm travel through a series of spermatic ducts to reach the urethra

• the pathway is the efferent ductules→ rete testis→epididymis (about 18 ft long) and is where sperm maturation occurs→ ductus/vas deferens→ ejaculatory ducts

Ductus (vas) deferens

• sperm travels up the spermatic cord through the inguinal canal, passes behind the bladder, widens into the ampulla, and emptying into the urethra via ejaculatory ducts

• where vasectomy occurs

Accessory glands for the male reproductive system

1. seminal vesicles

   1. near the end of the ductus deferens, yellowish fluid (60% of semen—gives the yellow color) & provides energy

2. Prostate

   1. inferior to the bladder, has 30% fluid, helps provide enzymes

3. Bulbourethral glands

   1. base of the penis, has clear fluid for lubrication and protection

4. Semen

   1. 10% sperm

   2. 30% prostatic fluid

   3. 60% seminal vesicle fluid

The Penis

• Internal root- the base where it cannot be seen

• The shaft— the long part of the penis that hangs

• The glans—the head of the penis

• The prepuce—the foreskin (often cut off)

• three erectile tissues

Erectile tissues of the penis

• corpus spongiosum—alongside the corpus cavernosum

• left and righ corpus cavernosum—runs through the shaft

• penile urethra—carries urine (also known as the spongy urethra

Penis blood supply

• The penis receives blood from the internal pudendal arteries which receive blood from the internal iliac arteries

• the internal pudendal then branches into the dorsal and deep arteries

  • the deep arteries are within the corpus cavernosum

  • the dorsal arteries are one above each corpus cavernosum