Chapter 16 – Reproductive System

Male Reproductive System

1. General Terms – gonads, gametes, haploid (1N), diploid (2N)

Gonads – the primary sex organs, testes in males; ovaries in females, they produce gametes

Gametes – sex cells; sperm in males; ovum in females

Haploid (1N) – having half the number of chromosomes in the human species; 1N equals 23 chromosomes

Diploid (2N) – having the full amount of chromosomes in a particular cell of the human species; 2N equals 46 chromosomes

2. Male reproductive system organs include the testes and a system of

ducts:

Seminiferous Tubules – tightly coiled tubules located in the Testes, sight of spermatogenesis

Epididymus – the first part of the duct system where the sperm finish maturing (spermiogenesis)

Interstitial Cells – cells located in the connective tissue surrounding the seminiferous tubules that produce testosterone (androgen)

Sertoli Cells – special cells in the testes that provide nourishment to the spermatids

Ductus Deferens – the duct that carries sperm through the spermatic cord from the testes to the urethra

Urethra – common passageway for sperm and urine

3. Accessory organs are glands that secrete semen; they are:

Seminal Vesicles – paired glands located on the posterior aspect of the urinary bladder that add about 60% to semen; fructose, vit. C, prostaglandins, fibrinogen

Prostate – single gland located just inferior to the bladder, secrete fluid that activates sperm

Bulbourethral Glands – paired glands located inferior to the prostate, secretion that cleanses the urethra of traces of acidic urine.

Ejaculatory Duct – duct formed in the prostate by the combining of the duct from the seminal vesicles and the ductus deferens

4. The external genitalia of the male

Includes the penis and the scrotum

5. Semen – is the combination of sperm and accessory gland secretions.

6. Know your structures from the lab.

7. Define spermatogenesis and spermiogenesis and where they take place.

Spermatogenesis – production of sperm; mitosis, then meiosis I and meiosis II

Spermiogenesis – maturation of sperm

8. Know the structure of mature sperm.

Sperm Head – contains the DNA, chromosomes (haploid), essentially, it is the nucleus of the sperm, anterior to the head is the acrosome (helmet-like structure) which is similar to a large lysosome; when the sperm penetrate through the follicle cells

Midpiece – filaments which form the tail, arise from centrioles in the midpiece, mitochondria wrapped tightly around these filaments provide the ATP needed for the whiplike actions of the tail

Tail – flagella made from the centrioles in midpiece

9. Hormones that regulate androgens (male sex hormones.)

GnRH, FSH, LH

10. Male secondary sex characteristics (caused by testosterone)

1) Deepening of the voice (enlargement of larynx)

2) Increased hair growth all over the body

3) Enlargement of skeletal muscles

4) Increased heaviness of the skeleton due to thickening of the bones

Female Reproductive System

1. Terms – Ovaries – gonad of female

· Size and shape of almond

· Contains follicles; each follicle consists of an immature egg called an oocyte surrounded by one or more layers of cells called follicle cells

· Endocrine – Estrogen secreted by the follicular cells; progesterone produced by the corpus luteum

· Exocrine – production of oocytes (eggs) to be ovulated into duct system called fallopian tubes

Fallopian Tubes – about 4” long; extend medially from ovary

to empty into the superior region of the uterus

· Little or no contact with ovary; distal end is funnel shaped infundibulum in which finger-like projections extend called fimbriae

· Oocyte carried toward the uterus by combination of peristalsis and cilia; journey takes 3-4 days

· Site of fertilization is in tube usually upper 1/3

· Oocyte is viable for up to 24 hours

Uterus – located between urinary bladder and rectum; hollow

Organ; very muscular and about the size of a pear in a female

That has never been pregnant

· Major portion of uterus is called body; superior end called the fundus; the narrow outlet inferiorly located which protrudes into the vagina is the cervix

· Three layers form the wall, 1) endometrium, 2) myometrium, 3) perimetrium (serous layer)

Vagina – thin walled tube 3-4 inches long which extends

from the cervix to the body exterior, also called the birth

canal

2. External female genitalia – also called vulva

- mons pubis, labia majora, and minora, clitoris, urethral and

vaginal orifices, greater vestibular glands (produces mucus)

3. Know the hormones that regulate female cycle from onset of puberty

to menopause. FSH, LH, Progesterone, Estrogen

- Hormone secreted by fetus (HCG)

4. Ovarian Cycle

· Days 1-13 (Follicle Stage)

· Day 14 (Ovulation)

· Days 15-28 (Luteal Stage)

5. Menstrual Cycle (Uterine Cycle)

· Days 1-5 (Menses)

· Days 6-14 (Proliferative Stage)

· Days 15-28 (Secretory Stage)

6. Oogenesis

7. Secondary Sex Characteristics (brought about by estrogen)

· Enlargement of the accessory organs of the female

· Reproductive system (uterine tubes, uterus, vagina, external genitals)

· Development of breasts

· Appearance of body hair

· Increased deposits of fat beneath the skin in general

· Widening and lightening of the pelvis

· Onset of menses, or the menstrual cycle