Anatomy and Physiology: The Reproductive Systems PDF

Anatomy Anatomy and and Physiology Physiology Final Chapter: 20 The Reproductive Systems  Function of Reproductive Systems To continue the human species by the production of offspring. The male and female reproductive systems produce gametes, sp...

Anatomy Anatomy and and Physiology Physiology Final Chapter: 20 The Reproductive Systems  Function of Reproductive Systems To continue the human species by the production of offspring. The male and female reproductive systems produce gametes, sperm and egg cells, and ensure the union of gametes in fertilization following sexual intercourse.  Meiosis Produces gametes 1 cell with the diploid number of chromosomes (46) divides twice to form four cells, each with the haploid number of chromosomes (23).  Spermatogenesis Takes place in the testes. Seminiferous tubules contain spermatogonia, or sperm- generating cells. FSH initiates sperm production Testosterone, secreted when stimulated by lutenizing hormone, promotes maturation of sperm. Inhibin decreases the secretion of FSH.  For each primary spermatocyte that undergoes meiosis, four functional sperm cells are produced. This production begins at puberty. Millions are formed each day. As men age they decrease production but never cease.  Oogenesis Process of Meiosis for egg cell formation Begins in ovaries and regulated by hormones. FSH initiates the growth of ovarian follicles, which contains an oogonium or egg generating cell.  FSH stimulates the follicle cells to secrete estrogen, which promotes maturation of ovum. Each primary oocyte, only one functional egg is produced, the other three cells are polar bodies. (they deteriorate)  A mature ovarian follicle actually contains the secondary oocyte; the second meiotic division will take place if and when fertilized. Production begins at puberty and continues until menopause. Egg production is cyclical, with a mature ovum being produced every 28 days.  The haploid egg and sperm cells each have 23 chromosomes. When fertilization occurs they then have 46.  Testes Located in the scrotum, a sac of skin between the upper thighs. Temperature is 96 degree slightly lower than body temperature, in order to produce sperm. In the male fetus, the testes develop near the kidneys, and descend into the scrotum just before birth.  Divided into lobes. Each lobe contains seminiferous tubules, in which spermatogenesis occurs. Sustentacular cells, produce inhibin, which stimulated by testosterone.  Between the seminiferous tubules are interstitial cells, which produce testosterone when stimulated by LH. Sperm – Head contains 23 chromosomes Acrosome which contains enzymes to digest the membrane of an egg cell. – Middle piece – mitochondria that produce ATP – Flagella – provides motility.  Sperm from seminiferous tubules enter a tubular network called rete testis, then enter the epididymis.  Epididymis Tube 20 feet long coiled on the posterior of each testis. Here sperm complete their maturation and flagella become functional. Smooth muscle propel the sperm into the ductus deferens.  Ductus Deferns Also called vas deferens, extend from epididymis in scrotum into the abdominal cavity through the inguinal canal. The inguinal canal is an opening the muscle and is a natural weak spot (hernia formation)  Once inside the abdominal cavity, the ductus deferens extends upward over the urinary bladder, then down the posterior side to join the ejaculatory duct on its own side. The smooth muscle layer of the ductus deferens contracts in waves of peristalsis as part of ejaculation  Ejaculatory Ducts receive sperm from the ductus deferens and the secretion of the seminal vesicle on its own side. They empty into single urethra.  Seminal Vesicles Posterior to the bladder. Secretion contains fructose to provide energy source for sperm and is alkaline to enhance sperm motility. Each duct joins the ductus deferens on that side to form the ejaculatory duct.  Prostate Muscular gland below the urinary bladder. Surrounds the first inch of the urethra. Glandular tissue secretes an alkaline fluid that helps maintain sperm motility.  The smooth muscle of the prostate contract to contribute to the expulsion of semen from the urethra.  Bulbourethral Glands Also called Cowper’s glands Located below the prostate gland and empty into the urethra. Alkaline secretion coats the interior of the urethra just before ejaculation, which will neutralize any acidic urine  All secretions are alkaline because the female vagina is acidic. It also promotes sperm motility.  Urethra - Penis Urethra is the last of the ducts that semen travels. Longest portion is enclosed in the penis. Penis is the external genital organ Distal end is called the glans penis. Covered with skin called foreskin. – circumcision  3 masses of cavernous tissue that contains blood sinuses, smooth muscle, and connective tissue. When blood flow is minimal, the penis is flaccid. During sexual stimulation, the arteries of the penis dilate, the sinuses fill with blood, and the penis becomes erect and firm. This is parasympathetic.  Erect penis is capable of penetrating the female vagina to deposit sperm. The culmination is ejaculation.  Semen Consists of sperm and the secretions of the seminal vesicles, prostate glands, and bulbourethral glands. pH 7.4 2-4 ml semen is expelled. Each ml contains 100 million sperm cells.  Female Reproductive System Ovaries pair of oval structures about 1.5 inches long on either side of the uterus in the pelvis cavity. Broad ligament is a fold of the peritoneum that keeps the ovaries in place.  Several hundred thousand primary follicles, present at birth. Only 300-400 will mature. Each primary ovarian follicle contains an oocyte, a potential ovum or egg cell.  Surrounding the oocyte are the follicle cells, which secrete estrogen. A mature follicle may also be called a graafian follicle, and the hormone LH causes ovulation, or rupture of the mature follicle with release of the ovum  Other developing follicles begin to deteriorate. The ruptured follicle becomes the corpus luteum and begins to secrete progesterone and estrogen.  Fallopian Tubes 4 inches long Lateral end encloses an ovary. – Fimbrae, fringelike projections that create currents in the fluid surrounding the ovary to pull the ovum into the fallopian tube. Medial end opens into the uterus.  Smooth muscle causes peristalsis to keep the ovum moving. Mucosa is ciliated to sweep the ovum toward the uterus.  Fertilization takes place within the fallopian tube. If not fertilized, it will dies within 24-48 hours and disintegrates. If fertilized, the ovum becomes a zygote and is swept into the uterus over 4-5 days.  Ectopic Pregnancy is if the embryo becomes implanted in the fallopian tube, the ovary itself, or elsewhere in the abdominal cavity.  Uterus 3 inches long by 2 inches wide Superior to the urinary bladder and between two ovaries in the pelvic cavity. Broad ligament covers the uterus  Fundus Body Cervix Myometrium Endometrium – Basilar layer – Functional layer  Vagina Muscular tube 4 inches in length. Extends from the cervix to the vaginal orifice in the perineum (pelvic floor) Posterior to the urethra and anterior to the rectum  Partially covered by thin membrane called the hymen, which is ruptured by sexual intercourse. Functions are to receive sperm from the penis during sexual intercourse Serve as an exit for menstrual blood flow Serve as birth canal at the end of pregnancy.  Normal flora creates an acidic pH that inhibits growth of pathogens.  External Genitals Another name for vulva. Clitoris Labia majora Labia minora Bartholin’s glands  Mammary Glands Produce milk for the nourishment of offspring. Glandular tissue is surrounded by adipose tissue. Alveolar glands produce milk after pregnancy  The milk enters lactiferous ducts which converge at the nipple. The skin around the nipple is pigmented and called the areola. During pregnancy, estrogen and progesterone prepare glands for milk production.  Prolactin Oxytocin  The Menstrual Cycle Menstrual Phase Follicular Phase Luteal Phase Cycle is 28 days Amenorrhea r/t reduction of body fat  Prostatic Hypertrophy Enlargement of prostate Benign prostatic hypertrophy is a common occurrence in men over age of 60. Enlarged prostate compresses the urethra within it and may make urination difficult or result in urinary retention  Prostatectomy is surgical removal of part of all prostate Ejaculation may be impaired Newer procedures may preserve sexual function  Cancer of Prostate 2nd most common cancer among men Usually over age of 50 Treatment: removal of prostate, radiation therapy, or hormone therapy to replace testosterone.