Anatomy and Physiology Hole’s Human Anatomy and Physiology Eleventh Edition Shier w Butler w Lewis Chapter 22 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Male Reproductive System Primary sex organ (gonads) testes Accessory sex organs: Epididymis Ductus deferentia – aka vas deferens Seminal vesicles Prostate gland Bulbourethral gland Scrotum Penis

Testes Suspended by spermatic cord Within saclike structure called the scrotum Develop in same area of kidneys but descend through inguinal canal before birth Green box p.850 Cryptorchidism Inguinal hernia Strangulated hernia posterior view

Structure of the Testes Constructed of seminiferous tubules Seminiferous tubules lined with epithelium from which sperm is made Interstitial cells are between seminiferous tubules and secrete male hormones P. 851 Testicular cancer

Formation of Sperm Cells Spermatogonia in seminiferous tubules undergo meiosis to produce sperm

Spermatogenesis Through meiosis one primary spermatocyte will produce 4 sperm cells.

Structure of a Sperm Cell Three Regions Head Acrosome – enzymes that aid in penetration of egg Nucleus – contains 23 chromosomes Midpiece – contains mitochodria which produce energy needed for sperm to move Tail – flagellum used for movement

Leeuwenhoek’s idea of sperm Actual Sperm Leeuwenhoek’s idea of sperm

Epididymides tightly coiled tubes connected to ducts within testis secretes substances that promote maturation of sperm cells Immature sperm stored there until they reach maturation

Ductus Deferentia Aka vas deferens muscular tubes about 45 cm each extends from epididymis to ejaculatory duct which is the tube that leads into the urethra Functions is to carry sperm from epididymis to urethra

Seminal Vesicles attached to vas deferens near base of bladder secrete alkaline fluid which regulates pH needed for sperm secretes fructose which sperm use for energy Secretes prostaglandins that cause muscular contractions within female reproductive organs contents empty into ejaculatory duct

Prostate Gland surrounds proximal portion of urethra ducts of gland open into urethra secretes a thin, milky, alkaline fluid secretion enhances mobility of sperm and sustain them by neutralizing acidic conditions both from sperm themselves and within female reproductive system P.858 Clinical Application: Enlarged Protate

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Bulbourethral Glands Aka Cowper’s gland inferior to the prostate gland secrete mucus-like fluid fluid released in response to sexual stimulation

Semen Includes sperm cells secretions of seminal vesicles, prostate gland, and bulbourethral glands slightly alkaline – pH approximately 7.5 120 million sperm cells per milliliter Sperm live for weeks in testes but only about 3 days (72 hours) outside of male body

Scrotum pouch of skin and subcutaneous tissue dartos muscle smooth muscle in subcutaneous tissue Helps maintain optimal temperature for sperm by moving testes closer or further away from body medial septum divides scrotum into two chambers each chamber houses a testis and epididymis

Penis conveys urine and semen to outside of body specialized tissue designed to become erect for insertion into the vagina

Penis Consists of 3 layers of tissue Urethra extends through Distal end forms glans penis where urethral opening is found Contain pairs of arteries, veins, and nerves Circumcision – prepuce (foreskin) is removed

Hormonal Control of Male Reproductive Functions hypothalamus releases gonadotropin-releasing hormone (GnRH) GnRH stimulates the anterior pituitary to produce gonadotropins (LH and FSH)

LH and FSH FSH – follical stimulating hormone stimulates spermatocytes to produce sperm LH – luteinizing hormone stimulates interstitial cells to produce androgens (male hormones)

Actions of Testosterone The androgen testosterone is responsible for secondary sex characteristics. increased growth of body hair sometimes decreased growth of scalp hair enlargement of larynx and thickening of vocal cords thickening of skin increased muscular growth thickening and strengthening of the bones

Hormone Regulation Hormone levels are regulated by a negative feedback system between the hypotalamus, anterior pituitary, and testes. Levels increase with puberty (begins around age 10)

Female Reproductive System Primary sex organ (gonads) ovaries Accessory sex organs: Uterine tubes (fallopian tubes) Uterus Vagina

Ovary Attachments Ovaries and uterus are held in place by ligaments.

Primordial Follicles Females are born with approximately 1 million primordial oocytes. At puberty these begin to develop and be released one per month.

Oogenesis beginning at puberty primary oocytes undergo meiosis Results in one secondary oocyte Unequal division of the cytoplasm results in development of polar bodies which degenerate

Follicle Maturation Mature (Graafian) follicle Primordial follicle Egg matures in a fluid filled, blister-like follicle Maturation of a follical takes about 10-14 days.

Follicle Maturation Several follicles will be maturing at the same time just at different rates.

Ovulation Wall of follicle ruptures releasing the oocyte. Green box P. 870 Clomid

Ovulation

Uterine Tubes aka Fallopian Tubes About 10 cm long convey eggs toward the uterus Fingerlike projections called fimbriae direct egg into tube Lining has cilia that help move egg downward

Lining of Uterine Tubes

Uterus aka Womb hollow muscular organ that receives the embryo that has been fertilized in the uterine tube End of uterus that opens into vagina is called the cervix

Cervix Pap Smear is a test to check the cells of the cervix for any abnormality that might lead to or indicate cervical cancer HPV – human papilloma virus leading cause of cervical cancer

Uterine Wall 3 layers Endometrium – mucosal layer Myometrium – smooth muscle layer Perimetrium – serosa layer

Vagina aka Birth Canal fibromuscular tube that conveys uterine secretions, receives the penis during intercourse, and provides an open channel for offspring Opening from outside is partially covered by hymen – a membrane

Hormonal Control of Female Reproductive Functions estrogens inhibit LH and FSH during most of the reproductive cycle Birth control pills work because they are synthetic forms of estrogen and progesterone

Effects of Estrogens development of breasts and ductile system of the mammary glands increased adipose tissue in breasts, thighs, and buttocks increases vascularization of skin Body hair growth is due to androgens that increase at puberty

Female Reproductive Cycle Like in the male, the hypothalamus secretes GnRH GnRH stimulates the anterior pituitary to produce LH and FSH FSH stimulates a follicle to develop

Female Reproductive Cycle The follicle produces some estrogen LH stimulates cells within the ovary to produce estrogen precursors As a result of increasing estrogen levels the endometrium thickens

Female Reproductive Cycle A spike in hormone levels (LH and FSH) during mid-cycle will cause ovulation to occur (egg released) The leftover follicle, corpus luteum, secretes an increased level of progesterone.

Female Reproductive Cycle Progesterone causes the endometrium to become more vascular. If pregnancy does NOT occur the corpus luteum dries up and the hormone levels drop drastically As a result of the drop in hormone levels the endometrium is shed

Menopause usually occurs in late 40s or early 50s reproductive cycles stop ovaries no longer produce as much estrogens and progesterone some female secondary sex characteristics may disappear may produce hot flashes and fatigue hormone therapy may prevent effects on bone tissue

Mammary Glands located in the subcutaneous tissue of the anterior thorax within the breasts composed of lobes estrogens stimulate breast development in females

Birth Control coitus interruptus rhythm method mechanical barriers condom diaphragm cervical cap spermicidal foams or jellies chemical barriers spermicides oral contraceptives hormonal injectable contraception intrauterine devices surgical methods vasectomy tubal ligation

Surgical Methods of Birth Control Vasectomy Tubal ligation