1. Mammalian Reproduction
Group 2
III-Cesium

2. Male reproductive anatomy (overview)
Internal reproductive organs:
Gonads: produce gametes and hormones
Accessory glands: secrete products essential for sperm movement
Ducts: carry the sperm and glandular secretions
External reproductive organs:
scrotum
penis

3. Testes: the male gonads
Consist of seminiferous tubules interspersed with Leydig cells
Seminiferous tubules: sperm production ( approx. 200 mil/day)
Leydig cells: production of androgens (testosterone)
Following production, sperm pass into the epididymis

4. Epididymis Vas deferens Composed of 6 metre-long coiled tubules
Stores sperm for about 20 days
sperm mature and gain:
Ability to fertilize
Motility
Vas deferens
Two ducts, each running from the epididymis to the back of the urinary bladder
Ends in an ejaculatory duct
Opens into the urethra
During ejaculation, sperm are propelled from the epididymis through the vas deferens

5. Urethra
Tube that runs from the bladder through the prostate gland to the end of the penis
Functions in both the reproductive and the excretory systems:
Exit point for semen and urine
Closing of muscular sphincters
1. Urinary Bladder 2. Pelvic Urethra 3. Penile Urethra

6. Accessory glands Add secretions to semen Seminal vesicles
Semen: fluid ejaculated
Seminal vesicles
a pair of glands opening into the urethra
contributes 60% of the semen (3-5mL)
Supplies a thick, yellowish, alkaline fluid
Mucus
Fructose sugar (energy)
Coagulating enzyme
Ascorbic acid
prostaglandins

7. 3) Bulbourethral glands
2) Prostate gland
largest of the glands
Secretes a thin, milky-white fluid directly into the urethra
Anti-coagulant enzymes
Citrate (a sperm nutrient)
Slightly acidic
3) Bulbourethral glands
Pair of glands along the urethra
Produce a clear, alkaline mucus
Secreted into the urethra before ejaculation
Neutralize acidic urine
Also carries some sperm

8. External organs Scrotum Penis Fold of the body wall
Holds the testes outside the abdominal cavity
Sperm production cannot occur at normal body temperature (98.6F)
Temperature in scrotum: 95-97F
Not present in all mammals (e.g. whales, elephants)
Penis
Serves to deposit the sperm in the female genital tract
3 cylinders of spongy erectile tissue
Engorges with blood during arousal
Forms an erection necessary for insertion
Baculum: rodents, raccoons, walruses
Bone that helps stiffen the penis
Glans penis: head of the penis
Covered by a prepuce (foreskin)
Also functions in the excretory system

9. Female Reproductive anatomy (an overview)
Internal reproductive organs:
Gonads: produce the eggs
Ducts and chambers:
channel the gametes
Accommodate the embryo and fetus
External Reproductive organs:
Clitoris
Labia minora
Labia majora

10. Ovaries: the female gonads
Lie in the abdominal cavity
Enclosed in a tough, protective capsule
Contain the follicles (approx )
Follicles: one egg cell and its emveloping layers of follicle cells
Formed before birth
Follicle cells: nourish and protect the cells
Produce estrogens
Release the egg during ovulation
Ovulation: release of an egg from the ovaries during the menstrual cycle
Corpus lutaeum: composed of remaining follicular tissue
Grows within the ovary
Secretes estrogens and progesterone
Disintegrates if egg is not fertilized

11. Oviduct (fallopian tube)
Duct that opens with a funnel-like entrance
Lined with cilia
Collects the egg upon release
Conveys the egg cell from the ovaries to the uterus
Uterus (womb)
Thick, muscular organ
Expands during pregnancy
Endometrium
Inner lining of the uterus
Highly vascularized

12. Cervix: neck of the uterus
opens into the vagina
Vagina
Thin-walled chamber
Functions:
Birth canal
Repository of sperm during intercourse
Hymen: partial covering of the vagina
Ruptured during copulation/intense physical activity

13. Vestibule Clitoris Contains the vaginal and urethral openings
Bordered by the labia minora
Slender skin folds
Enclosed by the labia majora
Thick, fatty ridges
Clitoris
Located at the front edge of the vestibule
Engorges with blood during arousal
Consists of:
Rounded glans (covered by a prepuce)
Supporting shaft
Erectile tissue

14. Bartholin’s glands Mammary glands Secrete mucus into the vestibule
Lubrication
Facilitates intercourse
Mammary glands
Consist of:
Small sacs of epithelial tissue
Secrete milk
Adipose tissue
Function only in women

15. Human sexual response Terms: Coitus: sexual intercourse
Vasocongestion: swelling of body tissues due to increased arterial blood flow
Myotonia: increased muscle tension

16. The sexual cycle is divided into 4 phases
1) excitement
Readies the vagina and penis for coitus
Involves:
Enlargement of testes, labia, breasts
Vaginal lubrication
Vasocongestion of vagina and penis
Myotonia in arms and legs
2) plateau phase
Continues responses begun in excitement phase
Increase in breathing and heart rates
Formation of a depression at the back of the vagina
For the reception of sperm

17. 3) Orgasm: rhythmic, involuntary contractions of reproductive structures
2 phases:
Emission: contraction of glands and ducts
Forces sperm into the urethra
Ejaculation: expulsion of semen (2-5 mL; mil sperm)
Prostaglandins thin mucus at the opening of the female uterus
Stimulates contraction of uterine muscles, moving up the coagulated semen
Anticoagulants liquify the semen
Sperm swim through the female tract

18. 4) Resolution: final phase
Reverses the effects of the previous stages
Vasocongested organs relax

19. Structure of the sperm cell
Produced via spermatogenesis
Occurs in the seminiferous tubules
Consists of:
Head
Haploid nucleus
Acrosome: anterior-most organelle
Contains enzymes: sperm penetration
Varied shapes (oval, spherical, comma)
Neck
Middle piece
Mitochondrion: ATP for tail movement
Tail (flagellum)

20. Structure of the egg cell
Oogenesis: production of ova
Ova: mature, unfertilized egg cells
Consists of:
Yolk: cell substance
Germinal vesicle: nucleus
Germinal spot: nucleolus
Zona pellucida: thick, transparent envelope surrounding the egg cell
Corona radiata: surrounds the zona pellucida
Layers of cells derived from the follicle

21. FIN