LO8: Reproductive System Flashcards
What are the testes?
Slightly flattened oval structures enclosed in a tough fibrous capsule, they are located with in the scrotum
What are the primary organs of the male reproductive system?
The testes.
They form sperm and the sex hormone testosterone
What does each lobule of the testes contain?
- a seminiferous tubule: produce sperm and empty ducts which unite to form the epididymis
- interstitial cells: located between the seminiferous tubule and function to produce and secrete testosterone
What is the epididymis?
A single coiled duct that adheres to the posterior surface of each testis
Functions as the site of maturation and temporary storage of sperm
What is the vas (ductus) deferens?
A muscular tube that passes upward along the posterior side of the epididymis
They travel through the inguinal canal into the pelvic cavity to the back of the urinary bladder where they each unite with the fact of one of the seminal vesicles to form the ejaculatory duct
What is the spermatic cord?
A connective tissue sheath that encloses the blood vessels and vas (ductus) deferens
When is each ejaculatory duct formed?
When vas deferens unites with the duct from a seminal vesicle. The two ejaculatory ducts are located within the prostate and empty in to the prostatic urethra
Where are the seminal vesicles located?
Posterior to the urinary bladder
What do the seminal vesicles secrete?
A viscous fluid that contains:
- a sugar called fructose which nourishes the sperm and provides energy production
- prostaglandins which stimulate contractions with in the female reproductive tract aiding sperm transportation towards the egg
What % of the volume of semen does the fluid from the seminal vesicles constitute?
60%
Where is the prostate gland located?
Inferior to the urinary bladder and surrounds the urethra
What does the prostate gland secrete?
An alkaline fluid which functions to enhance the mobility of sperm
How does the growth of the prostate work?
- -Small in size from birth to puberty
- From then it grows rapidly over the next several years
- From 30-45 it remains the same size
- Then after that it enlarges in about half of all men enough to press on the urethra
What are the bulbourethral glands?
2 small pea sized glands located inferior to the prostate gland on either side of the urethra
-They produce an alkaline fluid that neutralized the acidity in the urethra and provides lubrication for intercourse
What is semen?
- A mixture of sperm cells and secretions from the seminal vesicle, prostate gland, and bulbourethral gland
- Semen has a slightly alkaline pH
- Contains fructose which nourishes the sperm and prostaglandins which aid sperm movement through the female reproductive tract
What is the average number of sperm present in each millilitre of semen?
120 000 000
What does the penis consist of?
The shaft which is enlarged at its distal end to form the glans
This cone shaped glans contains the external urethral orifice
What covers the glans as a sheath?
A loose fold of skin called the prepuce or foreskin
What is the penis composed of internally?
3 cylindrical masses of erectile tissue, these columns contain spaces which fill with blood upon sexual stimulation
What is the scrotum?
A pouch of skin that hangs from the perineum, it is divided into two chambers each occupied by a testis
What is spermatogenesis?
The process of sperm production, it occurs continuously throughout the reproductive life of a male
How many chromosomes does a mature sperm have?
23
22 body chromosomes
1 sex chromosome (either x or y)
Where is the acrosome located?
On the top of the head of the sperm. Its a cap that contains enzymes that:
-aid the sperm to penetrate the ovum during fertilization
What is the mid piece?
Its located behind the head and contains millions of mitochondria which provide the energy necessary to move the tail
-The wave like motion of the tail provides the motility of the sperm
Where are the sperm stored?
In the epididymis and vas deferens until ejaculation
-As they pass through the epididymis they mature and gain the ability to move independently
What are the factors necessary in order for sperm to be produced, matures and function properly?
- An environmental temperature (2-3 degrees below body temp 34) in order to develop
- The presence of FSH which stimulates the seminiferous tubules to produce sperm
- Testosterone which is required for the production of sperm
- Nutrients to keep the sperm alive
- Slightly alkaline medium necessary for mobility
What are the environmental factors which may lead to DAMAGED sperm?
- overcrowding
- stress
- smoking
- chemical air pollution
- radiation
- poor nutrition
How long can sperm survive in the female genital tract?
48 hours
What is testosterone produced by?
Interstitial cells of the testes
What hormone stimulates the production of testosterone?
Luteinizing hormone which is produced by the anterior pituitary gland
What is testosterone responsible for?
- enlargement of male reproductive organs
- development of male secondary sex characteristics
- production and maturation of sperm
What are the male secondary sex characteristics?
- skeletal and muscle development
- changes in the larynx causing a deeper voice
- development of axially and pubic hair along with apocrine sweat glands
- facial hair
- aggression
- libido
What are the primary organs of the female reproductive system?
Ovaries