STUDY GUIDE-REPRODUCTIVE SYSTEM WRITTEN AND LAB

how is sex determined?

Male sex is determined at fertilization by the inheritance of an XY chromosome pair, specifically driven by the Y chromosome's SRY gene, which triggers testis development.

significance of the testes

The testes function as primary male reproductive organs, essential for producing sperm within seminiferous tubules and secreting testosterone via Leydig cells

Seminiferous tubules and interstitial cells.

Seminiferous tubules are the tightly coiled tubes inside the testes where sperm is produced.

interstitial cells (Leydig cells) are located in the spaces between the seminiferous tubules and are responsible for producing and secreting male sex hormones like testosterone

Male secondary sex organs, their structures, and functions.

• Scrotum: A muscular, skin-covered sac housing the testes, acting as a climate control system by contracting or relaxing to maintain the 2-4°C lower temperature needed for spermatogenesis.

• Epididymis: A coiled tube attached to each testis where sperm mature, gain motility, and are stored.

• Ductus (Vas) Deferens: A muscular tube that transports mature sperm from the epididymis to the ejaculatory duct via peristalsis during ejaculation.

• Ejaculatory Duct: Formed by the union of the vas deferens and seminal vesicles; it expels semen into the urethra.

• Urethra: A 8-10 inch muscular tube passing through the prostate and penis, serving as the exit pathway for both urine and semen.

• Seminal Vesicles: Glands that produce 50-80% of semen volume, including fructose (nourishment) and alkaline fluids.

• Prostate Gland: A walnut-sized gland surrounding the urethra that adds alkaline, milky fluid to semen to enhance sperm motility and survival.

• Bulbourethral (Cowper's) Glands: Pea-sized glands that secrete a clear, slippery alkaline fluid to lubricate the urethra and neutralize residual acidic urine before ejaculation.

• Penis: External organ composed of erectile tissue (shaft) and the tip (glans), responsible for delivering semen into the female reproductive tract

Anatomy of the sperm

the head, the midpiece, and the tail.

Physiology of the male reproductive system in terms of puberty.

Puberty begins with signals from the brain. This sequence of events triggers the maturation of the reproductive system

• Testosterone: The primary male sex hormone. It is produced by Leydig cells in the testes. It triggers secondary sex characteristics and drives the male sex drive (libido).

• 🧪 Dihydrotestosterone (DHT): A derivative of testosterone. It is responsible for the growth of the prostate, facial hair, body hair, and male pattern baldness.

  • 🧪 FSH and Sertoli Cells: FSH stimulates Sertoli cells in the testes to nourish and support developing csperm

  • Before puberty, the testes are dormant. At puberty, the hormonal surge triggers the creation of mature sperm cells.

  • Growth spurt: Rapid increase in height and skeletal muscle mass.

  • Voice change: The larynx enlarges, causing the voice to deepen.

  • Hair growth: Development of pubic, axillary (underarm), chest, and facial hair.

  • Organ growth: Significant enlargement of the testes, scrotum, and penis.

  • Skin changes: Increased activity of sebaceous (oil) glands, which can lead to acn

the pathway of sperm

starts with production in the testes and travels through the epididymis, vas deferens, ejaculatory ducts, and urethra. Along this path, sperm mature in the epididymis and mix with fluids from the prostate and seminal vesicles to form semen before ejaculation

the sexual response in males

excitement (arousal), plateau, orgasm (including ejaculation), and resolution

Effects of aging on the male reproductive system.

slow decline in testosterone (1–2% yearly after age 20), reduced testicular volume, and decreased sperm motility/quality. Erectile function often decreases in frequency and rigidity, while libido may decline

Hypospadias

is a congenital defect in which the urethra

opens on the ventral side or base of the penis instead of

on the tip of the glans

Hydrocele

is a condition in which fluid has accumulated

and causes swelling in the scrotum.

Epididymitis

is inflammation of the epididymis, usually

caused by a bacterial infection.

Phimosis

s a condition of the penis characterized by tight

foreskin that cannot be pulled back over the glans penis.

The primary and secondary female reproductive organs and structures and their

functions

The primary reproductive organs, or gonads, are responsible for producing the female gametes (eggs) and sex hormones.

Internal Structures

• Fallopian Tubes (Uterine Tubes): Two narrow tubes that extend from the ovaries to the uterus.

  • Function: They provide a pathway for the egg to travel to the uterus. They are also the typical site where fertilization by sperm occurs.

• Uterus (Womb): A hollow, pear-shaped, muscular organ.

  • Function: It is designed to house, protect, and nourish a developing fetus. If pregnancy does not occur, its inner lining (the endometrium) is shed during menstruation.

• Cervix: The lower, narrow part of the uterus that connects to the vagina.

  • Function: It acts as a gateway that allows sperm to enter the uterus and menstrual blood to exit. It dilates to allow a baby to pass through during childbirth.

• Vagina: A muscular, elastic canal that extends from the cervix to the outside of the body.

  • Function: It serves as the receptacle for the penis during intercourse, acts as the birth canal, and provides a route for menstrual flow to leave the body.External Structures (The Vulva)

    • Mons Pubis: A rounded, fatty tissue pad located over the pubic bone.

      • Function: It provides physical protection to the pubic bones and contains sweat and oil-secreting glands.

    • Labia Majora: Fleshy, hair-covered outer folds of skin.

      • Function: They enclose and protect the other, more delicate external reproductive organs.

    • Labia Minora: Smaller, hairless inner folds of skin that lie just inside the labia majora.

      • Function: They surround and protect the vaginal and urethral openings.

    • Clitoris: A small, highly sensitive protrusion located where the labia minora meet.

      • Function: It is composed of erectile tissue and is the primary center for sexual sensation.

    • Bartholin's Glands: Two small glands located beside the vaginal opening.

      • Function: They secrete mucus-like fluid to provide lubrication during sexual intercourse

Know the walls of the uterus

the inner endometrial lining, the middle muscular myometrium, and the outer perimetrium serosa.

Know the structure and function of the breast

The breast is a complex, specialized organ. Its primary biological function is lactation (milk production), but it also plays important roles in sensation and body image

the hormonal control of puberty in the female

Female puberty is initiated by the hypothalamus releasing GnRH, which triggers the pituitary gland to secrete FSH and LH, stimulating ovaries to produce estrogen. This hormonal surge causes primary physical changes, including breast budding (thelarche), growth of reproductive organs, fat redistribution, and eventual menarche

Know the primary and secondary sex characteristics of the female

Female primary sex characteristics are reproductive organs present at birth (ovaries, uterus, vagina, vulva) that mature during puberty. Secondary sex characteristics, driven by estrogen during puberty, include breast development, hip widening, body hair (pubic/underarm), and fat redistribution

Know the female sexual response

The female sexual response is a complex, often non-linear process involving physical arousal (vasocongestion/muscle tension) and psychological desire, typically moving through excitement, plateau, orgasm, and resolution

Know the effects of aging on the female reproductive system.

Aging causes a significant decline in the female reproductive system, characterized by a sharp reduction in egg quantity/quality after age 35 and leading to menopause (typically ages 45–55

What is breast cancer?

Breast cancer is a disease where cells in the breast grow out of control, forming malignant tumors that can invade surrounding tissue or spread throughout the body

emission

Transport of sperm cells to the urethra

The site of sperm production

the testes

Produce secretions to provide protection and nutrition for the

sperm cells

Several glands in the male reproductive system

Contains erectile tissue to make it easier to deliver semen

into the female reproductive system

the penis

Transports semen and urine

The urethra

Ciliated epithelial tissues ensure that the secondary oocyte

does not pass into the body cavity.

fallopian tubes

The endometrium is replaced on a cyclical process under

the control of hormones

Contains about 100 000 primary oocytes that could develop

into female gametes.

ovary

Secretions are neutralised by alkaline seminal fluid during

intercourse.

vagina

Becomes plugged with mucus during pregnancy to provide

a protective seal for the uterus against the entry of

pathogens and against leakage of uterine fluids.

cervix