I.Male Reproductive System

Organs: testes, ducts, glands & supporting structures Supporting structures include scrotum & penis

Ducts: epididymis, ductus deferens, ejaculatory ducts & urethra

Glands: seminal vesicles, prostate, bulbourethral glands

Figure 23.1

A. Scrotum

Pouch that supports the testes Septum separates into separate sections for

each testis Sperm requires temperatures 2-3oC below

body temperature allows raising and lowering testes to adjust

temperature

B. Testes

Paired oval glands

200-300 lobules containing seminiferous tubules

Sperm producing cells and nurse cells (protect sperm)

C. Epididymis

Stores sperm before ejaculation Comma shaped on top of testes

Figure 23.2a

Figure 23.2b

D. Spermatogenesis

Occurs in seminiferous tubules Cell types involved: spermatagonia, sertoli cells & interstitial

cells (leydig cells)

move into->epididymis

Spermatogenesis stages

Takes ~65-75 days from first division to release

~300 million /day Life span ~ 48 hrs in female tract

Figure 23.3

E. Sperm

Structure: Head, middle, tail tail- flagellum = motility Middle - mitochondria = energy Head-chromosomes + acrosomal cap acrosome-enzymes-> penetrating egg

Figure 23.4

F. Sperm route

Testes ->Epididymis vas (ductus) deferens urethra

G. Semen

2.5-5 ml per ejaculation 50-150 million sperm per ml When number falls below 20 million/ml –

sterile 7.2-7.7 ph

H. Accessory Glands

Seminal vesicles- seminal fluid- Fructose (sperm ATP production + alkalinity (neutralize acid in tracts) 60% of ejaculate

Prostate- surrounds upper urethra Increases volume + adds antibiotics Citric acid for energy 25% of ejaculate

Bulbourethral glands: More alkalinity + mucus fluid Pre ejaculate 10 % of ejaculate

I. Penis

Contains urethra-Passage for semen & urine

Glans has external urethral oriface Uncircumcised glans covered by

prepuce

Figure 23.6

II.Female Reproductive System

Ovaries: paired organs- produce secondary oocytes ova (after fertilization) Hormones: progesterone & estrogens From same embryonic tissue as testes

uterine (fallopian) tubes & uterus vagina External organs (vulva or pudendum)

A. Histological Structure of Ovary

Germinal epithelium- covers surface Ovarian cortex: connective tissue containing

follicles Follicle; oocyte + surrounding cells

Surrounding cells nourish oocyte & produce hormones

Grows during maturation Graafian follicle ovulation Post ovulation corpus luteum

Progesterone, relaxin & inhibin

Figure 23.6

Figure 23.7

B. Uterine Tubes

Two tubes- extend laterally from uterus End in fringe Fimbriae Fimbriae sweep secondary oocyte into tube Oocyte moved by cilia lining wall Zygote reaches uterus in ~7 days

C. Uterus

Pathway for sperm & site of implantation Fundus -Dome-shaped area above tubes= Body – tapering central portion Cervix- narrow opening into vagina Uterine cavity- interior of body

Vagina

extends from exterior to cervix Receptacles for penis and outlet for menstrual flow Fornix- recess surrounds cervix Acid environment- prevents bacterial growth Smooth muscular layer- adjusts for intercourse or

birth Thin membrane fold can cover vaginal orifice =

hymen

Figure 23.9

Perineum & vulva (cont.)

Clitoris- small cylindrical mass of erectile tissue & nerves Also contains prepuce & glans

External urethral oriface- anterior to vaginal oriface

Female Reproductive Cycle

20-34 days- cycles in both ovaries & uterus Ovarian cycle= maturation of follicle, ovulation &

corpus luteum formation Uterine Cycle= menstrual cycle

controlled by hormones from ovary Estrogens growth of endometrium Progesterone

supports endometrium for implantation Combine cycles = Reproductive cycle

Figure 23.12

Hormonal Regulation

GnRH (hypothalamus) controls GnRH FSH & LH FSH follicle growth & estrogen secretion High estrogen LH surge ovulation LH supports corpus luteum progesterone &

estrogen secretion + relaxin & inhibin Inhibin decreased FSH release

Gonadotropin releasing hormone= GnRH

Comes from hypothalamus and stimulates the release of FSH from pituitary.

Hormones

FSH – Follicle stimulating hormone Follicle stimulated to start maturing an egg Starts to rise at the end of the cycle and during

menstruation. An egg starts to mature. Spikes during ovulation

LH- Lutenizing hormone Peaks as estrogen peaks Helps to cause ovulation

Hormones

Estrogen: Development & maintenance of reproductive

structures & secondary characteristics Tells the uterine lining to build up From follicle

Progesterone maintains uterine lining for implantation Prepares breast for milk production From corpus luteum

hCG- human chorionic gonadotropin Made by embryo Tells corpus luteum to keep making

progesterone to maintain lining

Relaxin= relaxes uterus- inhibits myometrium

Inhibin- inhibits FSH release

Phases of Cycle

Menstrual phase: ~1st 5 days of cycle Several Ovarian follicles enlarge Decreased progesterone & estrogen uterine arteries

constrict endometrium sloughs off

Preovulatory- between menstruation & ovulation Ovaries: follicles grow & secrete estrogen & inhibin one

dominates Uterus: growth of new endometrium

Phases of Cycle (cont.)

Ovulation Release of 2o oocyte with LH surge

Postovulatory- Ovaries: follicle collapses corpus luteum

(luteal phase) If no fertilization FSH & LH corpus

albicans & decreased Progesterone menstruation

Phases of Cycle (cont.)

If fertilization & division human chorionic Gonadotrophin (hCG) stimulates corpus luteum secretion

Uterus: Progesterone & estrogens complete development of uterus for implantation

Figure 23.13