Reproductive Systems Flashcards
What are gametes?
- Sex cells that fuse at fertilization to form a one-celled zygote, the first cell of the offspring
- Sperm from male parent
- Ovum from female parent
Describe the structure and location of the testes.
- Testes in scrotum (lower temperature)
- Covered by tunica albuginea which divides the testis into lobules containing seminiferous tubules
- Interstitial cells produce testosterone
Describe the structure of spermatozoa.
- Small, mobile cells
- Head contains genetic material
- Acrosome contains enzymes to assist sperm in penetration of ovum
- mitochondria in midpiece provide energy for movement
List the functions of testosterone.
- Promotes development of male accessory organs
- “Masculinizes” - bone mass, fat distribution, muscle mass and strength
- Production of RBCs and sperm
- Deepening of the voice during puberty
- Facial and pubic hair growth at puberty
- Regulates libido
List and describe the reproductive ducts of the male reproductive system.
- Epididymis - single, coiled tube about 6m in length; lies along the top and behind each testis in the scrotum; sperm mature and develop the capacity for motility as they pass through the epididymis
- Vas deferens - also called ductus deferens; receives sperms from epididymis and transports them from scrotal sac through the abdominal cavity; passes through inguinal canal and then joins duct of seminal vesicle to form the ejaculatory duct
List and briefly describe the glands of the male reproductive system and what each gland contributes to seminal fluid.
- Seminal vesicles - pouchlike glands that produce about 60% of seminal fluid volume; secretion is yellowish, thick and rich in fructose to provide energy needed by sperm for motility
- Prostate gland - shaped like a doughnut and located below the bladder; urethra passes through the gland; secretions represents 30% of seminal fluid volume; thin and milk coloured; activates sperm and is needed for ongoing sperm motility
- Bulbourethral (cowper) glands - resemble peas in size and shape; secrete mucus-like fluid constituting less than 5% of seminal fluid volume.
Name the two types of erectile tissue in the penis.
- Corpora cavernosa - two dorsal columns
- Corpus spongiosum - one ventral column surrounding urethra
Describe the structure and location of the ovaries.
- Paired glands weighing about 3g each
- Resemble large almonds
- Attached to ligaments in pelvic cavity of each side of uterus
Explain the development of an ovarian follicle from the primary follicle to the corpus luteum.
After ovulation, the ruptured follicle collapses and most of the follicle cells remain in the ovary. These follicle cells hypertrophy and become a postovulatory follicle or corpus luteum. The corpus luteum is a transitory organ that has a hormonal regulatory role in the reproductive cycle.
List the functions of estrogen.
- Produced by the ovaries
- Responsible for the development and maintenance of secondary sexual characteristics of young female during puberty
- Responsible of menstruation, ovulation, breast growth, and the vascularization of the skin.
List the functions of progesterone.
- Thickening the lining of uterus for implantation
- Regulating bleeding during menstruation
- Supporting a pregnancy once conception occurs
- Helping to improve your mood
- Supporting thyroid function
- Supporting lactation
What is oogenesis?
- Involves meiotic cell division that produces daughter cells with equal chromosome numbers (23) but unequal cytoplasm
- Ovum is large; polar bodies are small and degenerate
Describe the structure of uterine tubes.
- Uterine (fallopian) tubes (oviducts) extend about 10cm from uterus into abdominal cavity
- Expanded distal end surrounded by fimbriae
- Mucosal lining of tube is directly continuous with lining of abdominal cavity
Describe the structure of the uterus.
- Composed of body, fundus, and cervix
- Lies in pelvic cavity just behind urinary bladder
- Myometrium is muscle layer
- Endometrium is lost in menstruation
Describe the structure of the vagina.
- Distensible tube about 10cm long
- Located between urinary bladder and rectum in the pelvis
- Receives penis during sexual intercourse and is birth canal for normal delivery of baby
Describe the structure of the greater and lesser vestibular glands.
- Secrete mucous fluid that may lubricate during sexual intercourse
- Ducts open between labia minora
- Clinically important when they become infected (as in gonorrhea)
Describe the structure of breasts.
- Located over pectoral muscles of thorax
- Size determined by quantity of fat tissue more than amount of glandular (milk-secreting) tissue
- Lactiferous ducts drain at nipple, which is surrounded by pigmented areola
- Lymphatic drainage important in spread of cancer cells to other body areas
Explain what occurs during the menses phase of the reproductive cycle.
- About the first 4 or 5 days of the cycle, varies somewhat
- Characterized by sloughing of bits of endometrium with bleeding
- First day of flow is day one of menstrual cycle
Explain what occurs during the proliferative phase of the reproductive cycle.
- Days between the end of menses and secretory phase; varies in length
- The shorter the cycle, the shorter the proliferative phase; the longer the cycle the longer the proliferative phase
- Characterized by proliferation of endometrium
Explain what occurs during the secretory phase of the reproductive cycle.
- Days between ovulation and beginning of next menses; secretory phase about 14 days before next menses
- Characterized by further thickening of endometrium
- Secretion by its glands in preparation for implantation of fertilized ovum
Explain what occurs during ovulation.
- Typically one ovum released per cycle, 14 days before next menses
- Control - combined actions of the anterior pituitary hormones FSH and LH cause ovulation; sudden sharp decrease in estrogens and progesterone brings on menstruation if pregnancy does not occur
