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