The Reproductive System Male Reproductive System Testes Epididymis

The Reproductive System

Male Reproductive System

Testes

Epididymis o o o Comma-shaped, tightly coiled tube Found on the superior part of the testis and along the posterior lateral side Functions to mature and store sperm cells (at least 20 days)

Vas Deferens o o o Carries sperm from the epididymis to the ejaculatory duct Passes through the inguinal canal and over the bladder Moves sperm by peristalsis Ends at ejaculatory duct unites with the urethra Vasectomy

Seminal Vesicles o o base of the bladder Produces a thick, yellowish secretion (60% of semen) n n Fructose (sugar) Vitamin C Prostaglandins (stimulate muscle contractions) Other substances that nourish and activate sperm

Prostate Gland o Encircles the upper part of the urethra o Secretes a milky fluid n o Helps to activate sperm Prone to cancer (like most glands)

Semen o Fructose provides energy for sperm cells o Alkalinity (base) of semen helps neutralize the acidic environment of vagina o Semen inhibits bacterial multiplication o 120 million/ml

External Genitalia o Scrotum. Maintains testes at 3°C lower than normal body temperature to protect sperm viability o dartos muscle o medial septum divides scrotum into two chambers o

Cont. . o Penis o Regions of the penis n Shaft n Glans penis n Prepuce (foreskin) n Often removed by circumcision

Sperm Only Human cell with flagellum. Head Contains DNA

Testosterone Production o o o o Produced in interstitial cells Functions- Stimulates reproductive organ development Underlies sex drive Causes secondary sex characteristics Deepening of voice Increased hair growth Enlargement of skeletal muscles Thickening of bones

Female Reproductive

Ovaries o Structure of an ovarian follicle n n Oocyte Follicular cells

Support of Ovaries

Uterine (Fallopian) Tubes o o o Receive the ovulated oocyte Provide a site for fertilization Attaches to the uterus Does not physically attach to the ovary Fimbriae Cilia inside the uterine tube slowly move the oocyte towards the uterus (takes 3– 4 days)

Uterus o o o Located between the urinary bladder and rectum Functions of the uterus n Receives n Retains n Nourishes Cervix – narrow outlet that protrudes into the vagina

Vagina o Serves as the birth canal o Receives the penis during sexual intercourse o Hymen

External Anatomy

Oogenesi s

Hormone Production by the Ovaries o Estrogens n Cause secondary sex characteristics o Enlargement of accessory organs o Development of breasts o Appearance of pubic hair o Increase in fat beneath the skin o Widening and lightening of the pelvis o Onset of menses

Mammary Glands o Present in both sexes, but only function in females…most of the time! n Modified sweat glands o Function is to produce milk o Stimulated by sex hormones (mostly estrogens) to increase in size