Chapter 19: Reproductive System

What are the functions of the Reproductive System?

• production of gametes

• Fertilization

• Development & nourishment of new individuals

• production of sex hormones

GAMETES

sex/reproductive cells

What are the male sex cells?

Sperm

What are the female sex cells?

oocytes (eggs)

MEIOSIS

cell division that creates sex cells

Which organs does meiosis occur?

testis & ovary

How many chromosomes are in a sperm cell & oocyte?

23 chromosomes

CHROMATIDS

one of the two identical halves of a chromosome that has been replicated in preparation for cell division

How many chromosomes are in the beginning of meiosis?

46 chromosomes

How many chromatids do each chromosome consist of in the beginning of meiosis?

2 chromatids

SYNAPSIS

when chromosomes align as a pair

CROSSSING OVER

allows exchange of genetic material between chromosomes

What is produced during Meiosis I?

2 haploid cells (23 chromosomes with 2 chromatids each)

What is the final result of meiosis?

4 haploid cells (23 chromosomes)

FERTILIZATION

union of sperm & oocyte

ZYGOTE

• fertilized oocyte

• after fertilization

When does a zygote become an embryo?

3-14 days after fertilization

What does the male reproductive system consist of?

• testes

• ducts

• accessory glands

• supporting structures

What are the ducts of the male reproductive system?

• epididymis

• ducta deferens

• urethra

What are the accessory glands of the male reproductive system?

• seminal vesicles

• prostate gland

• bulbouretheral gland

What are the supporting structures of the male reproductive system?

• scrotum

• penis

What kind of temperature does sperm develop in?

less than normal body temperature

SCROTUM

contains testes & dartos muscle

DARTOS MUSCLE

moves scrotum & testes close to & away from body depending on temperature; loose connective tissue

CREMASTER MUSCLES

extension of abdominal muscles into scrotum; contracts & pulls testes near body

TESTES

main male reproductive organ with the purpose of producing sperm; aka gonads

Contains:

• seminiferous tubules

• interstitial cells

• germ cells

• sustentacular cells

Where is sperm produced?

Seminiferous tubules

INTERSTITIAL CELLS

endocrine cells that secrete testosterone

What cells do sperm cells arise from?

Germ cells

SUSTENTACULAR CELLS

nourish germ cells & produce hormones

SPERMATOGENESIS

formation of sperm cells

When does spermatogenesis occur?

begins in male at puberty

What happens when spermatogenesis occurs?

• interstitial cells: increase in # & size

• seminiferous tubules: enlarges & produce germ & sustentacular cells

SPERMATOGONIA

most peripheral germ cells; divide through mitosis

PRIMARY SPERMATOCYTES

other daughter cells that divide by meiosis; becomes sperm cell

SECONDARY SPERMATOCYTES

product of 1st meiotic division

SPERMATIDS

product of secondary meiotic division

SPERM CELL/SPERMATOZOON

developed spermatid w/ head, midpiece & flagellum

What is the production of sperm cells? (GSP3S)

1. germ cells

2. spermatogonia

3. primary spermatocytes

4. secondary spermatocytes

5. spermatids

6. sperm cells

What is the sperm cell structure?

• head (nucleus & DNA)

• mid piece (mitochondria)

• tail (flagellum for movement)

EPIDIDYMIS

• thread like tubules on each side of testis

• where seminiferous tubules empty new sperm

• sperm continue to mature and develop here

DUCTUS DEFERENS

• vas deferens

• from epididymis & joins seminal vesciles

• cut out during vasectomy

SEMINAL VESICLE

sac shaped near ampulla of each ductus deferens

EJACULATORY DUCT

2 seminal vesicle & ductus deferens joined together at the prostate gland; enters prostate gland & joins urethra

URETHRA

urinary bladder to end of penis; passageway for urine & male reproductive fluids

PENIS

transfers sperm from male to female; excretes urine

What are the 3 columns of erectile tissue?

• corpus cavernosum

• corpus spongiosum

• spongy urethra

GLANS PENIS

distal ends of penis forms a cap

EXTERNAL URETHRAL ORIFICE

spongy urethra that opens to exterior

PROSTATE GLAND

size of walnut; surrounds urethra

BULBOURETHRAL GLAND

mucus secreting gland near base of prostate gland

SEMEN

mixture of sperm & secretion from glands; provide transport medium & nutrients that protect & activate sperm

Where is the majority of fluid in semen from?

Seminal vesicles

PROSTAGLANDINS

from seminal vesicles; decrease mucus thickness around cervix & uterine tubes to help sperm move through female reproductive tract

PROSTATE FLUID

contains enzymes to liquify semen after it is inside female; neutralizes acidity of vagina

What does the secretion of the bulbouretheral gland do?

neutralize acidity of male urethra & female vagina

How much semen is ejaculated each time?

2-3 mL of semen

How long can sperm live inside the female body?

72 hours

Path of Sperm

1. developed in testes

2. mature in epididymis

3. ductus deferens

4. receives secretion from seminal vesicles, prostate & bulbourethral gland

5. exits through urethra

GONADOTROPIN-RELEASING HORMONE (GnRH)

produced in hypothalamus;

stimulates release of LH & FSH from anterior pituitary

LUTEINIZING HORMONE (LH)

produced in anterior pituitary;

stimulates release of testosterone & causes ovulation

FOLLICLE-STIMULATING HORMONE (FSH)

produced in anterior pituitary;

prompts spermatogenesis & follicles in ovaries to develop

What are examples of secondary sexual characteristics?

• skin texture

• fat distribution

• hair growth

• skeletal muscle growth

• larynx changes

SECONDARY SEXUAL CHARACTERISTICS

structural & behavioral changes other than reproductive organs

TESTOSTERONE

major sex hormone; negative feedback effect on GnRH, LH, & FSH; produced in interstitial cells of testes; development & maintenance of reproductive organs

INHIBIN

negative feedback effect on FSH secretion; by seminiferous tubules

EMISSION

accumulation of sperm cells & semen in urethra; movement of sperm cells, mucus, prostatic secretion & seminal vesicle secretions into prostatic, membranous, & spongy urethra

EJACULATION

forceful expulsion of secretions that accumulated in urethra to exterior

ORGASM

result of pleasurable, intense sensations

RESOLUTION

phase after ejaculation where penis becomes flaccid (opposite of erect0; overall feeling of satisfaction

ERECTION

first major component of male sex act; parasympathetic AP sent to skeletal muscles surrounding base of penis

What does the female reproductive system consist of?

• ovaries

• uterine tubes

• uterus

• vagina

• external genitalia

• mammary glands

BROAD LIGAMENT

spreads on both side of uterus & attaches to ovaries & uterine tubes

OVARIES

primary female sex organs; produces oocytes & sex hormones

OVARIAN LIGAMENTS

anchor ovaries to uterus

SUSPENSORY LIGAMENTS

anchor ovaries to pelvic cavity

OVARIAN FOLLICLE

group of cells in ovaries containing oocytes

OOGENESIS

process of gamete production in females

When does oogenesis begin in females?

Before birth; females are born with all their oogonia

How long do oocytes live for?

24 hours

UTERINE (FALLOPIAN) TUBES

part of uterus that extends toward ovaries & receives oocytes

FIMBRAIAE

fringe-like structures around opening of uterine tubes; help sweep oocytes into uterine tube

Where does fertilization usually occur?

the part of uterine tube near ovary, called the ampulla

TUBAL LIGATION

sterilization of females

UTERUS

pear sized structure located in pelvic cavity

What are the functions of the uterus?

receive, retain & provide nourishment of fertilized oocyte, where embryo resides & develops

What are the parts of the uterus?

• body (main part)

• fundus (superior to entrance of uterine tubes)

• cervix (narrow region leading to vagina)

What are the 3 layers of the uterine wall?

• perimetrium

• myometrium

• endometrium

PERIMETRIUM

serous; outermost layer

MYOMETRIUM

muscular; middle layer composed of smooth muscle

ENDOMETRIUM

innermost; sloughed off during menstruation

VAGINA

uterus to outside of body; contains muscular walls & mucous membrane; very acidic to keep bacteria out

What are the external female genitalia?

• vulva

• mons pubis

• labia majora

• labia minora

• clitoris

• prepuce

• vestibule

VULVA

external female sex organs

MON PUBIS

fatty layer of skin covering pubic symphysis

LABIA MAJORA

larger, outerfold of skin surrounding entrance of vagina;

= to scrotum

LABIA MINORA

thin, inner fold of skin surrounding entrance of vagina

CLITORIS

small erectile structure located in vestibule;

= to penis

PREPUCE

where 2 labia minora unite over clitoris

vestibule

space where vagina & urethra located