Physiology Flashcards
What cells can be found in the seminferous tubules? What do these cells secrete?
Testes descend into scrotum when?
Gonads of males and females are similar in appearance until differentiation by secretion of which hormone? How many weeks gestation does this occur?
germinal cells: sperm
Sertoli cells: inhibin
Leydig: Testosterone
Testes descend into scrotum through the inguinal canal shortly before birth (2-3mo)
Males and females gonads are similar in appearance until differentiation by secretion of testosterone from the leydig cells, this masculinizes the embryonic structures between 8-14wks.
Testes:
- function
- what structures make up the testes?
- where do the testicular arteries to this region stem from?
- what is the name of the venous circulation to this area? Whats its function?
- what are the two layers of tissue that directly surround the testicle?
Function: spermatogenesis and testosterone production.
Structures: Testes are made up of seminiferous tubules. The seminiferous tubules contain sertori, leydig, and germ cells.
Vasculature: testicular arteries branch from the abdominal aorta superior to the pelvis.
The pampiniform plexus (veins) helps cool the testes so they dont overheat.
Tunica vaginalis (inner) and tinuca albuginea (outer)
Describe testicular descent and the hormones involved.
Testicular descent occurs in two stages.
- 7-12wks fetal life anti-mullerian hormone prevents the development of uterus and fallopian tubes.
- 7-9mo testosterone is responsible for the descent of testes into the scrotum, pulls the contents of the spermatic cord down. (artery, veins, and lymphatics)
Scrotum:
- function
- muscles and their functions
function: houses testes; protection, and temp control
muscles:
- dartos muscle: smooth muscle causing wrinkling when cold, responds to temperature by either elevating when cold or descendiing when hot.
- cremaster muscle: skeletal muscles, elevate the testes when cold and descends when too hot.
Describe the genital duct system of the male. (from testes to urethra)
Testes compsed of seminiferous tubules, this is the site of sperm production. Tubules lead into the efferent ducts emerge to join the epididymis. Sperm still cant siwth so they rely on peristaltic movements of the ductal walls of the epididymis. From the epididymis they travel through the vas deferens. Upon ejaculation the sperm passes by the seminal vesicle, through the prostate and past the bulbourethral gland to the urethra. Semen now leaves the body.
What is the function of the epididymus?
How long can sperm live in the epididymis?
What is the storage site for sperm?
What is important education for pts undergoing vasectomy?
Function epididymus = final site for sperm maturation.
Sperm can live in the epididymis for 42days.
Storage is in the vas deferens.
Vasectomy: men can remain fertile for 4-5wks post vasectomy, make sure to educated patients on proper birth control/clearing ejaculant before relying on this surgical procedure for birth control.
What is the function of the following:
- seminal vesicles
- prostate gland
- bulbourethral glands (cowpers)
seminal vesicle: secrete fructose for sperm motility, prostaglandins to assist in fertilization by making the cervical mucous more receptive to sperm and by causing peristaltic contractions in the uterus and fallopian tubes to move the sperm toward to ovary.
Prostate: secretes thin milky alkaline fluid. Fibromuscular gland inferior to the bladder.
Cowpers/bulbourethral: alkaline mucus, helps nuetralize the vagina and urine.
What are the 3 masses of erectile tissue?
2 masses are corpora cavernosa (lateral)
1 mass corpus spongiosum (ventral)
Describe endocrine regulation of games.
refer to print out or page 1341 in porth.
FSH and LH act on which cells? What do these cells secrete and what negative feedback results do they have?
FSH works on the sertori cells secreting inhibin thereby inhibiting FSH at the Anterior pituitary
LH works on the Leydig cells which secrete testosterone thereby inhibiting LH at the anterior pituitary and at the level of the hypothalamus.
Which hormone is responsible for initiation and maintenance of body changes in puberty? What are these changes?
Testosterone
Changes: stimulates growth of muscles, larynx, and bone growth until sealing of epiphyseal discs. Promotes hemoglobin synthesis, responsible for spermatogenesis & is responsible for final maturation.
Function of FSH?
What is the determining factor in the development of male or female genital organs and characteristics?
Function of FSH: stimulates spermatogenesis to occur (also requires testosterone)
TESTOSTERONE is THE determining factor.
If a male child is born with undescended testicles what do you do?
administer testosterone or LH, this will cause the testes to descend BUT 80-90% of the time the testes will descend on their own if you just give them time. (by 1 year of age)
Testosterone is responsible for the development of primary and secondary sex characteristics, give examples of each.
Primary: cause penis, scrotum, and testes to enlarge during puberty
Secondary:
- body hair
- baldness (a man without functional testes does not become bald)
- deepened voice
- increased skin thickness
- more prone to acne
- muscular development
- bone growth, density, calcium retention.
What is intersex?
Intersex = both ovarian and testicular tissue is present in the body OR an individual with either testes or ovaries but not both who have accessory sex organs and external genitalia that are incompletely developed or inappropriate.
MC cause of pseudohemaphrodditism is congenital adrenal hyperplasia
Testicular feminizing syndrome: normal functioning testes but lack of receptors for testosterone