Male Reproduction Flashcards
1
Q
Sexual Reproduction
A
- Male Gonads: testes produce sperm
- Female Gonads: ovaries produce eggs
- Fusion of male and female sex cell called fertilization which produces a zygote
- Zygote divides many times to form an embryo which turns into a fetus
2
Q
Penis
A
- Sex organ designed to deliver sperm to female
- Part of urinary and reproductive system
- contains erectile tissue
- contains urethra
- Consists of shaft w/ enlarged tip called glans penis surrounded by prepuce
3
Q
What is a circumcision
A
- removal of foreskin
4
Q
What happens during sexual excitement
A
- Arterioles dilate, causing blood to enter
- inc blood flow to erectile tissue causes penis to become enlarged and erect so that sperm can be delivered
- erectile tissue compressed venules
- erection maintained due to decreased venous blood from constricted venules
5
Q
Erectile Dysfunction (impotency)
A
erectile tissue doesnt expand enough to compress veins
- viagra increases blood flow to penis
6
Q
Scrotum
A
- Divided sac of skin that hangs outside of abdominal cavity
- Contains two testes
- Testes develop in abdomen and descend into pouch
- keep temp of testes 2-3 lower than body temp for healthy sperm
- wrinkles up and move testes closer to body to inc temp when its cold
- when hot, it can extend farther away from body
7
Q
Testes(Testicles)
A
- oval shaped glands
- produce sperm cells in seminiferous tubules
- Produce male sex hormone, testosterone, in interstitial cells surrounding seminiferous tubules
8
Q
Seminiferous Tubules
A
- Tightly packed tubes “sperm factories” located inside each testis where sperm divide and differentiate into mature sperm (spermatogenesis)
- lined w/ sperm producing cells (spermatogonia)
- sperm division starts in walls of tubules
- mature sperm released into center of tube
- contains sertoli cells and spermatogenic cells
9
Q
Spermatogenic cells
A
- Produce sperm
- Lining of seminiferous tubules
10
Q
Sertoli Cells
A
- Protect n nourish developing sperm until they are mature
- Provide barrier between blood and seminiferous tubules (blood testis barrier)
- controls entry and exit of hormones, nutrients, and other chemicals into seminiferous tubules which protects developing sperm cells
- Secret inhibin
11
Q
Interstitial cells
A
- Cells surrounding seminiferous tubules
- where testosterone is produced (stimulates spermatogenesis)
12
Q
Epididymis
A
- Testes produce sperm cells, mature in epididymis
- Compact long coiled tube on exterior surface of testes
- Temporary storage site for immature sperm
- Takes about 20 days to go thru epididymis during time sperm mature n are able to swim
13
Q
Vas Deferens
A
- Walls of seminiferous tubules contract during sexual arousal to expel sperm thru vas deferens
- Tube connects with epididymis and transport sperm to urethra
- Connects to urethra thru ejaculatory duct
14
Q
Urethra
A
- Shared tube in males for urine and semen (not at same time)
- Sphincter at base of bladder closed by erection so urine cannot enter
15
Q
Sperm
A
- Special Haploid gamete cells (n=23)
- Head called acrosome which contains enzymes that help it penetrate egg and has nucleus (contains DNA)
- Middle part as mitochondria to produce ATP for movement
- Flagella (tail) for swimming
16
Q
Ejaculation
A
- Process of semen leaving body via penis
- Sperm leave body as semen which provides swimming medium for sperm
- Vas deferens, seminal tubules, ejaculatory duct, and prostate gland contract and force semen to base of penis
- Contractions force semen into urethra and out of penis
- 3-4mL of fluid containing w/ around 500 million sperm cells is released
17
Q
Semen
A
milky mixture containing sperm and seminal fluid
18
Q
Seminal Fluid
A
Fluid part of semen which is secreted by 3 glands:
- Seminal Vesicles
- Prostate Gland
- Cowpers Gland
19
Q
Seminal Vesicles
A
- Two glands that have duct leading to vas deferens and contains fructose and prostaglandins
20
Q
Fructose
A
- Sugar for energy for the sperm
- in seminal vesicles
21
Q
Prostaglandins
A
- Hormones that stimulate uterine contractions in female to help sperm move towards egg
- in seminal vesicles
22
Q
Prostate Gland
A
- Single large gland surrounding part of urethra
- produce thin milky, alkaline (basic) fluid that activates sperm to swim and protects them from acidic vagina
23
Q
Cowpers Gland (Bulbourethral Gland)
A
- Secretes alkaline fluid prior to ejaculation to neutralize acidity of urethra and facilitate sperm movement and lubrication
24
Q
Pathway of Sperm
A
- Produced in testes in seminiferous tubules
- Mature in epididymis
- Vas deferens carries ejaculate
- Passes seminal vesicle, prostate gland, and cowpers gland for seminal fluid creation
- Travels out through urethra
25
Hormonal Regulation in Males
- Hypothalamus releases GnRH which stimulates anterior pituitary gland to release 2 hormones:
FSH: promotes production of sperm in seminiferous tubules
LH: Acts on interstitial cells to produce testosterone
26
Testosterone
- Primary male sex hormone
- Stimulates maturation of testes and penis
- Stimulates spermatogenesis
- Introduces and maintains secondary sex characteristics: external features of organism that are indicative of its gender
- Includes: Tall, broad shoulders, larger muscles, coarse skin, deep voice, body hair, etc
- lvls of testosterone associated w/ male sex drive and linked to aggressive behaviour
27
During Spermatogenesis
1. Spermatogonia divide to form spermatocytes (46)
2. Spermatocytes differentiate into spermatids (immature sperm cells)
3. Spermatids have half number of chromosomes than other body cells (23)
4. Takes 9-10 weeks for spermatocytes to differentiate into sperm cells
