Reproductive_System.ppt

Reproductive System

Female Reproductive

I. Ovaries – paired organs

that weigh about 3

grams; female gonads A. Structure

Ovarian Structure, Cont.

2. Stroma –

connective region a. cortex – outer layer containing ovarian follicles

Ovarian Structure, Cont.

3. Ovarian follicles – consists of oocytes at varying stages of

development

4. Mature (Graafian) follicles – large fluid filled follicle that

releases the

Ovarian Structure, Cont.

5. Corpus Luteum – forms from the

ruptured follicle after ovulation and

produces

B. Location – one lies on each side of the pelvic cavity C. Functions

Oogenesis

a.

The process follows the same steps as

spermatogenesis, but the cytoplasm

division is unequal

b.

Meiosis I: Oogonia develop into primary

oocytes (some of the primary oocytes

become the primary follicles), then the

primary oocyte splits and forms a

Oogensis

c. Meiosis II: The secondary oocyte is frozen at metaphase II and will only continue the division cycle if fertilized. The secondary oocyte will then split and release the second polar body. The

larger cell is called the ovum

d. Summary: four cells are made; all have a

haploid number of chromosomes (23); one large cell filled with most of the cytoplasm (ovum or

Functions of Ovaries, cont.

II. Reproductive Ducts

A. Fallopian Tubes

(oviducts) – attach the ovaries and the uterus 1. The opening of the tube (infundibulum) is surrounded by

fingerlike (fimbriae) projections that gather secondary oocytes into the tube following

Fallopian Tubes, cont.

2. The oocyte is moved through the tubes by ciliary action and

peristaltic contractions.

B.

Uterus

– lies between the urinary

bladder and the rectum



1. Site of menstruation,

implantation of fertilized

ovum, and development of

fetus



2. Parts include the

Uterus, cont.



3. The muscular organ is held in place by

a series of ligaments



4. Uterine wall composed of 3 layers

(superficial to deep)

a. Perimetrium – visceral

b. Myometrium – middle smooth muscle

layer; active during labor

Endometrium layers, cont.

 i. stratum basalis –

permanent layer lying on top of the myometrium

 _{ii. Stratum functionalis –}

site of implantation;

C.

Vagina

– passage way for menstrual

flow and child



1. Extends from cervix to the exterior



2. Mucosa of vagina is acidic to slow

microbial growth



3. Muscular layer can stretch during sex

and birth



4. Thin fold of mucosa that covers the

III. External Genitalia (vulva)



A.

Mons pubis

– fatty rounded area

covered with hair



B.

Labia majora

– two hair covered folds

that run posteriorly to the mons pubis;

contains oil and sweat glands



C.

Labia minora

– inside hairless folds;

contain some sweat and many oil glands

External Genitalia, cont.



E.

Vaginal orifice

– opening of vagina



F.

Urethral orifice

– opening of the

urethra



G.

Bartholin’s gland

– produce mucous

for lubrication during sex



H.

Perineum

– area between vaginal

IV. Mammary Glands

A.

Modified sweat glands

that lie superficial to

the pectoralis muscles.

B.

Consists of

a. Lobes arranged in a

radial arrangement

b. Adipose tissue

Mammary Glands, cont.

 C. Alveoli secrete milk and the

milk is carried to the nipple by ducts.

 _{D. Main function is lactation –}

process of producing and ejecting milk.

 E. At puberty, estrogen and

V. Hormones that control the menstrual

and ovarian cycles



A. GnRH – (Gonadotropin Releasing

Hormone) In the hypothalamus, stimulates

release of FSH and LH



B. FSH – (Follicle Stimulating Hormone)

stimulates initial release of estrogen



C. LH – (Luteinizing Hormone) stimulates

the further maturation of ovarian follicles,

production of estrogen, progesterone,

Hormones, cont.



D. Estrogen

a. Maintains female structures

b. Promotes secondary sexual

characterisitics

c. Correct levels in the blood inhibit

release of GnRH



F. Progesterone – prepares the

VI. Relaxin – hormone that relaxes the

Male Reproductive System

Reproduction – is a process by which a species produces

offspring and pass on their genetic

I. Testes – paired oval glands that

descend into the scrotum in the

seventh week of fetal development



A. Structure

- 1. Covered by tunica albuginea, connective

tissue, that divides each testis into lobules which contain seminiferous tubules that produce sperm

 2. Interstitial cells that produce

Testes, cont.

 B. Location – housed in

the scrotum, when

muscle is relaxed provides a temp 3º C lower than

Testes, cont.



C. Function

1. Spermatogenesis – meiotic process of

sperm development; sperm has a haploid

number (23)

a. occurs in the seminiferous tubules

when FSH stimulates the spermatogonia

Spermatogenesis, cont.

c. Meiosis I: The primary

spermatocyte (1 cell) divide into the secondary

spermatocytes (2 cells)

d. Meiosis II: The secondary spermatocyte (2 cells)

divide into spermatids (4 cells)

e. Spermiogenesis: each

f. Sperm Structure



i. Head – contains genetic material



ii. Arcosome – enzyme that helps

penetration into the secondary oocyte



iii. Midpiece (mitochondria) – energy

production

2. Testosterone production – occurs in

the testes

a. Associated hormones

1. LH (Leteinizing hormone) – stimulates

testosterone secretion

2. FSH (follicle-stimulating hormone) –

stimulates spermatogenesis

3. GnRH (gonadotropin releasing

Testosterone production, cont.

b. Occurs at puberty (age 11-17) and

continues through life c. Develops the male

3. Reproductive ducts

 A. Epididymis

1. Comma shaped organ that lies

posterior to the testes 2. Consists of a tightly coiled tube called

ductus epididymis

B. Ductus (Vas) deferens

1. Receives sperm from the

epididymis

2. Penetrates the inguinal

canal (passageway to

abdomen); runs posterior to the urinary bladder

3. Stores and expels sperm 4. Sperm is expelled by

peristaltic contraction of muscular coat

5. Vasectomy – is cutting

C. Ejaculatory duct

1. Union of the ductus

deferens and the seminal vesicle

2. Eject sperm into

urethra D. Urethra

1. Terminal duct of

system

2. Passageway for

4. Accessory sex glands – secrete liquid

portion of semen

A. Seminal Vesicles – located at the base of the urinary

bladder

1. constitutes 60% of semen volume

2. secretes an alkaline

(protection against vaginal acid), viscous fluid that

contains fructose sugar

B. Prostate gland – doughnut shaped

organ inferior to the urinary bladder

1. Constitutes for 25% of the volume of semen 2. Secretes a milky,

slightly acidic fluid

that contains nutrients and several enzymes (gives semen its

color)

C. Bulbourethral (Cowper’s) Gland – pea

sized gland posterior to the prostate on

either side of the urethra

1. Secretes an alkaline fluid that neutralizes the

acid in the urethra (makes it sticky)

2. Also secretes mucous to lubricate the end of

D. Semen

1.

Mixture of fluid secreted by the

accessory glands and sperm (50-150

million per ejaculation)

2.

Provides sperm with nutrients,

5. External Genitalia

 1. Scrotum – is the external pouch that

consists of loose skin, superficial fascia, and smooth muscle.

 _{2. Penis – is a cylinder organ that transports}

semen and urine.

a. Body, cont.

 _{i. Corpus cavernosa -}

two dorsal masses

 _{ii. Corpus}

sponginosum – ventral mass contains the urethra

 _{iii. Skin and fascia}

enclose the erectile tissue

 _{iv. Erection – large}

amounts of blood enter the sinuses of penis

Receptors:

Cells in hypothalamus That secrete

GnRH

Effectors: Interstitial Endocrinocytes In testes secrete Some stimulus

Disrupts Homeostasis by Causing an Increase in testosterone Controlled Condition: normal blood level of testosterone Control Center:

Anterior Pituitary gland

cells Response:

Decrease in blood level of

testosterone, return to

I. Menstrual cycle and Pregnancy

A. 28 days

B. Three phases

1. Menstrual phase (first) – 5 days long

a. In ovary

b. In uterus

i. Most of the endometrium is

sloughed off and is flowing out

ii. Menstrual flow

consists of blood and tissue

iii. Discharge occurs

2. Preovulation phase (second) – 6

through 13

day of cycle.



a. In ovaries

i. Secondary follicles continue to

grow but one out grows them all and is

dominant

ii. The dominant follicle secretes

estrogen and inhibin to stop the growth of

the other follicles.

b. In the uterus

 _{i. Growth of endometrium because of the estrogen in the}

bloodstream

 _{ii. Endometrium doubles in size}

C. Ovulation – not a step in menstrual cycle!

a. The mature, dominant follicle bursts releasing the

secondary oocyte from the ovary, caused by high levels of LH

D. Postovulatory phase (third) – day 14 -

28

 a. Progesterone and estrogen stimulate

Pregnancy

 I. Follicle tissues

a. Corpus Luteum (CL) – produced by the surge of LH i. Contains remains of mature follicle

ii. Produces

1. progesterone (until it degenerates) 2. Estrogen

II. Ovaries after fertilization

 A. The corpus luteum

lives longer than 2 weeks

 i. releases progesterone

and estrogen to support pregnancy

 ii. CL is maintained by

human chorionic gonadotropin (HCG)  iii. The secretion of the

b. The HCG is released by the

Trophoblast

– the outer layer of tissue

on the embryo.

 i. Trophoblast secretes

HCG which keeps the CL alive and as a result of this, estrogen and

III. Uterus – prepares for implantation

about 7-8 days after ovulation

 A. Endometrium thickens

and becomes vascular.

 B. Endometrial glands

secrete glycogen

 _{C. The enzyme secreted}

IV. Menopause (ages

40-50)

 A. Occurs because of

degeneration of the ovaries.

 _{B. Menstrual cycle}