MALE REPRODUCTIVE SYSTEM Flashcards
define sexual reproduction?
process by which organisms produce offspring through production of germ cells called gametes
how many chromosomes do oocytes and sperm have?
half the number of chromosomes, 23 chromosomes each which combine to make a zygote containing 46 chromosomes
how are gamete’s produced?
by meiosis in specialised organs called gonads
name the 7 parts of the male reproductive system?
- penis
- scrotum
- testes
- epididymis
- vas deferens
- prostate gland
- seminal vesicles
list the 3 external organs of the male reproductive system?
- penis
- scrotum
- testicles
list the 3 internal organs of the male reproductive system?
- vas deferens
- prostate
- urethra
name and describe 4 primary functions of the male reproductive system?
- produce, maintain and nourish sperm and protective fluid (semen)
- ducts transport, store and assist in growth and development (maturation) of sperm
- discharge sperm, via the urethra, within the female reproductive tract
- produce and secrete male sex hormones
list 7 functions of testosterone?
- regulates sex drive (libido)
- regulates bone mass
- fat distribution
- muscle mass and strength
- production of red blood cells
- production of sperm
- small amount converted to oestradiol (form of oestrogen)
describe the structure of the scrotum?
- sac of skim and superficial connective tissue, hangs outside the pelvic cavity
- covered sparsely with hair, contains testes divided centrally by septum
explain why the scrotum are outside of the body?
the core body temperature (37°) is too warm to produce viable sperm, where outside the body is approximately 3° lower, an essential adaptation.
explain how the scrotum are affected by cold temperatures?
-the testes are pulled closer to the body
-scrotal skin wrinkles to reduce surface area and increase thickness
=less heat loss
describe the structure and function of the testes?
- oval shaped organs contained in a sac of skin called the scrotum
- approximately 4cm long and 2.5cm wide
- produces sperm and androgens such as testosterone
- covered by a fibrous capsule known as the tunica albuginea
- divided by partitions of fibrous tissue into 200-400 wedge shaped sections or lobes
- each lobe contains 3-10 coiled tubes known as seminiferous tubules which produce sperm
describe the blood supply to the testes?
- arterial supply from testicular arteries branching from the abdominal aorta
- testicular veins absorb heat from warmer arterial blood, helping keep testes at homeostatic pressure
describe what happens when the testes are hit forcefully?
- testes innervated by the sympathetic and parasympathetic nervous system
- when hit forcefully, sensory nerves transmit impulses that result in agonising pain and nausea
describe the role of the epididymis?
-the place where the sperm matures since it isn’t mature when it leaves the testes
describe the route of sperm after leaving the testes?
-immature (almost non motile) sperm moves slowly along the epididymis
—through fluid containing anti microbial proteins such as defensins
-as they move through over 20 days, sperm gain the ability to swim
-sperm can be held here for several months, if held longer destroyed by phagocytosis
-sperm is ejaculated from epididymis into the ductus deferens
describe the movement of sperm through the ductus deferens (vas deferens)?
- transport sperm during ejaculation to form ejaculatory duct
- after entering prostate gland, each ejaculatory duct empties into the urethra
- strong peristaltic waves squeeze the sperm forward into the urethra
what is a vasectomy?
-small incision through the scrotum, tied off/ burnt (cauterises) ductus deferens
—sperm still produced but can it reach the body exterior and eventually deteriorate and are phagocytosed
the penis is a copulatory organ, what does this mean?
it delivers sperm into the female reproductive tract
describe the structure of the penis?
- attached root and a free body
- ending in enlarged tip- gland penis
- covered in loose skin to form cuff, prepuce or foreskin
what happens during an erection?
- the penis enlarges and stiffens due to the engorgement of blood
- when not aroused, arteriolar are constricted do penis is flaccid
what is spermatogenesis?
-the sequence of events leading to the formation of sperm
-occurs in seminiferous tubules and is the indication of sexual maturity
—begins in puberty at around 14 years
-every 24 hours produces roughly 90 million sperm
describe the structure of the prostate gland?
- a single doughnut shaped gland about the size of a peach stone
- it encircles the urethra, just inferior to the bladder
explain what happens to the prostate gland during ejaculation?
- the smooth muscle of the prostate contracts, squeezing the secretions into the urethra
- prostatic fluid plays a part in activating sperm and accounts for up to 1/3 of semen volume
