notes: ch 46 animal reproduction (part 1)
TRANSCRIPT
NOTES: CH 46 – Animal
Reproduction (part 1)
MALE REPRODUCTIVE SYSTEM
Functions:
1) Produce sperm;
2) Deliver sperm to female repro. tract;
3) Produce androgens (male sex
hormones).
MALE REPRODUCTIVE SYSTEM -
Anatomy● TESTES
-develop in abdomen; descend
into scrotum before birth;
-made up of tightly coiled tubes
(SEMINIFEROUS TUBULES)
where sperm are formed;
-scattered between tubules are
the LEYDIG CELLS (produce
testosterone and other
androgens).
(Leydig cells)
TESTIS
● SCROTUM:
-a pouch of skin that
encloses the testes for
protection and
temperature regulation
MALE REPRODUCTIVE SYSTEM -
Anatomy
● EPIDIDYMIS
-6 meters of tubes;
sperm cells are here
for approx. 20 days;
-location where
sperm become
motile, gain ability to
fertilize.
MALE REPRODUCTIVE SYSTEM -
Anatomy
● VAS DEFERENS(muscular tube)
● EJACULATORY DUCT
● URETHRA
-tube that drains both repro. & excretory products
MALE REPRODUCTIVE SYSTEM -
Anatomy
● PENIS
-3 cylinders of erectile tissue (when filled with blood, penis becomes erect);
-head of penis = glans penis; has thinner covering; is covered by foreskin.
MALE REPRODUCTIVE SYSTEM
There are 3 sets of
accessory glands (add
secretions to semen):
1) SEMINAL VESICLES (2):
● produce 60% of semen
volume/fluid;
● fluid contains mucus,
fructose sugar (energy!),
coagulating enzyme,
prostaglandins.
MALE REPRODUCTIVE SYSTEM
Accessory glands (continued):
2) PROSTATE GLAND:
● secretes thin, milky, slightly alkaline fluid;
● fluid helps to balance the pH environment of the vagina.
MALE REPRODUCTIVE SYSTEM
Accessory glands (continued):
3) BULBOUREHTRAL GLANDS (2):
● secrete viscous mucus PRIOR to ejaculation
● fluid neutralizes any acidic urine in the urethra;
● carries some sperm;
● a.k.a. Cowper’s glands.
SEMEN
● consists of: sperm cells and
secretions from the seminal
vesicles, prostate gland,
bulbourethral glands
*typical semen production = 2-5
mL;
*semen first coagulates; then
thins & sperm begin to swim
through the female
reproductive tract…
FEMALE REPRODUCTIVE SYSTEM
Functions:
1) Produce egg cells;
2) Produce female hormones;
3) Nurture & protect developing fetus.
FEMALE REPRODUCTIVE SYSTEM -
Anatomy
● OVARIES:
-about size & shape of almonds
-contains many FOLLICLES…
The follicles…*surround, nourish, protect egg
cells;
*produce estrogens;
*mature and release egg during
monthly cycle (1 follicle per
month, starting at puberty and
ending at menopause)…this is
OVULATION;
*each becomes a CORPUS
LUTEUM following ovulation;
*disintegrate if egg is not fertilized.
FEMALE REPRODUCTIVE SYSTEM -
Anatomy
● OVIDUCTS (“FALLOPIAN TUBES”):
-cilia “pull” the egg cell in and convey the egg down the duct;
-fertilization occurs HERE!!!
● UTERUS (“womb”):
-thick, muscular organ; expands du ring pregnancy;
-inner lining = ENDOMETRIUM, which contains many blood vessels
FEMALE REPRODUCTIVE SYSTEM -
Anatomy
● CERVIX (neck of uterus)
● VAGINA (birth canal)
-thin-walled chamber where sperm are deposited;
-hymen = vascularized membrane which covers vaginal opening from birth until it is ruptured
FEMALE REPRODUCTIVE SYSTEM -
Anatomy
● BARTHOLIN’S GLANDS
-small glands near vaginal opening;
-secrete mucus during sexual arousal response.
● LABIA MINORA / LABIA MAJORA
-enclose and protect vaginal opening / urethral opening
Sexual Response:
Two types of physiological reactions predominate in both sexes during sexual arousal/response:
● Vasocongestion: filling of a tissue with blood
● Myotonia: increased muscle tension
GAMETE PRODUCTION:
● Spermatogenesis: production of sperm cells
● Oogenesis: development of ova
-see figures 46.12 (pg. 1006-1007)
Differences between
spermatogenesis & oogenesis:
SPERMATOGENESIS:
● All 4 meiotic products develop into mature sperm
● Sperm cells continue to develop throughout a male’s life
● Stages of meiosis occur continuously, in an uninterrupted sequence
Differences between
spermatogenesis & oogenesis:
OOGENESIS:
● Uneven cytokinesis; most
cytoplasm goes to 2°
oocyte (becomes ovum);
the other products (polar
bodies) disintegrate
● Female is born with all of
her egg cells
● Has long “resting” periods
of meiosis