Chapter 27 study guide

Describe and explain the major organs of the male reproductive system: scrotum, testes, epididymis, p*nis, ductus deferens, seminal vesicle, prostate, bulbourethral glands.

• Scrotum is a sac of skin & muscle that holds the testes outside the pelvic cavity. Main function is temperature regulation, keeping the testes slightly cooler than body temperature, which is necessary for proper sperm production

• The testes are the male gonads & have 2 major functions: produce sperm & produce testosterone. Sperm is produced in the seminiferous tubules and testosterone is produced by interstitial cells. They are the primary reproductive organs in males

• The epididymis is a long coiled tube attached to posterior side of each testis. This is where sperm mature, gain motility, and are stored until ejaculation

• The penis is the male reproductive organ & contains erectile tissue and functions to deliver semens during intercourse and serve as the passageway for urine through urethra

• The ductus deferens is a muscular tube that transports mature sperm from the epididymis toward the pelvic cavity. During ejaculation, it contracts to propel sperm into ejaculatory tract

• Seminal vesicles are glands located behind the bladder. Secrete a fluid that makes up a large portion of semen and their secretion contains fructose & subtances that help sperm movement and survival.

• The prostate gland is located below the bladder that surrounds part of the urethra. Produces a milky fluid that contributes to sperm, helps sperm motility and helps seme retain proper pH

• The bulbouretheral glands are the small glands near the base of the p*nis. They produce a clear mucus-like fluid released before ejaculation that lubricates the urethra neutralizes acidic urine residue in the urethra.

List and describe the discussed cells found in the testes.

• Spermatogonia are dipload stem cells located along the basement membrane of the seminiferous tubules. They divide by mitosis to produce cells that eventually become sperm

• Primary spermatocytes are formed from spermatogonia and are still diploid. They undergo meiosis I to produce secondary spermatocytes

• Secondary spermatocytes are haploid (n) after meiosis I and quickly undergo meiosis to form spermatids

• Spermatids are immature haploid sperm cells that don’t yet have a tail or or ability to swim. Undergo spermiogenesis where they develop into spermatoza

• Spermatoza are mature male gametes released into the lumen of the seminiferous tubules. Have a head (DNA + acrosome), midpiece (mitochondria), and tail (flagellum). Their function is to fertilize the egg

• Sertoli cells are found inside the seminiferous tubules & support developing sperm. Form the blood testis barrier and provide nutrients & protection. They support spermatogonia, secrete androgen-binding protein and produces inhibin

• Interstital cells are located between seminferous tubules. They produce testosterone in response to leuteinizing hormone (LH).

Describe the structure of sperm.

A mature sperm cell has 3 main regions: head, midpiece, and tail.

• The head contains the nucleus, which holds the haploid (23 chromosomes) genetic material, and the acrosome a cap-like structure filled with enzymes. It releases enzymes that help sperm penetrate the protective layers surrounding the egg during fertilization

• The midpiece contains many mitochondria. The mitochondria produce ATP to power the movement of the tail so sperm can swim through the female reproductive tract

• The tail is a long, whip-like structure that propels sperms forward using a swimming motion so it can reach the egg

Trace the development and path of sperm, from spermatocyte in seminiferous tubules to exiting the body.

1. Sperm production begins in the testes. Primary spermatocytes undergo meiosis to form spermatids which mature into spermatozoa. Sperm is then released into the lumen of the seminiferous tubules once formed.

2. Sperm then moves into the epididymis into the ductus deferens

3. Ductus deferens merges the duct of the seminal vesicle to form ejaculatory duct where seminal fluid from accessory glands mix with sperm

4. The ejaculatory ducts empty into the urethra. The urethra passes through the prostate gland & p*nis, carrying both urine & semen

5. Semen travels through the spongy urethra in p*nis and is expelled from the body through the external uretheral opening during ejaculation

Describe and explain the major organs of the female reproductive system: mons pubis, labia majora + minora, clitoris, lactiferous ducts, mammary glands, vagina, fallopian/uterine tubes, uterus, cervix.

• Mons pubisis a rounded pad of adipose tissue overlying the pubic symphysis. It becomes covered with pubic after puberty & functions as a protective cushion during sexual activity

• The labia majora are the outer folds that enclose & protect other external reproductive structures. They are homologus to male scrotum and contain adipose tissue & sweat glands

• The labia minora are thinner, inner folds of skin located within the labia majora and surround the openings to the vagina & urethra to help protect these openings while maintaining moisture

• Clitoris is a highly sensitive erectile erectile organ located at the anterior junction of labia minora. Contains erectile tissue & richly supplied with nerves, making it important for sexual arousal & pleasure

• Mammary glands are specialized glands in the breasts that produce milk after childbirth. Composed of lobes & lobules containing alveoli where milk is synthesized

• Lactiferous ducts are channels that carry milk from mammary glands to the nipple. Each gland has multiple ducts that converge near the nipple for milk release during lactation

• The vagina is a muscular, elastic canal that connects to the cervix of the uterus to external genitalia. Serves as a site for sexual intercourse, passageway of menstural flow, and the birth canal during childbirth

• The fallopian tubes extend from the uterus toward the ovaries. They capture the ovulated oocyte, are the typical site of fertilization, and transport the fertilized egg toward the uterus

• Uterus is a hollow, muscular organ where implantation and fetal development occur. It has 3 layers: endometrium (inner lining that thickens and sheds during menstruation), myometrium (smooth muscle layer and contracts during childbirth), and perimetrium

• The cervix is the narrow lower portion