Lecture Notes for General Biology BI 101 - Reproductive Systems




Hot Stuff for the end of the semester, Fall 04

I Reproductive System

	A) Current issues related to the Reproductive System: Abortion, 
		contraception, homosexuality, premature births, sperm and
			egg and embryo banks, drug abusing mothers, rape, 
			menopause, infertility, in vitro fertilization, fertility 
			pills, surrogate mothers, sex scandals (politicians, celebreties, other), etc....
	B) Contraception - preventing pregnancy

		History of contraception 
			Egyptians - honey, crocodile dung, fermented acacia extract as vaginal suppositories
			Romans and Greeks - lint tampon to block sperm, also used abortion to terminate pregnancy
			Europeans in Middle Ages - cedar oil, cabbage, pitch, ox-gall, elephant dung
			Europeans in the Renaissance - invention of the condom, vaginal sponge with brandy

		1) Behavioral techniques
Type Technique % effectiveness
Abstinence no sex 100%
Rhythm Method Natural Family Planning, intercourse before ovulation or during menstruation 76-90%
Coitus Interruptus or withdrawal pulling the penis out of the vagina before ejaculation 72-77%
		2) Barriers
Type Technique % effectiveness
Diaphragm barrier with spermicide 82-94%
Condom latex sheath placed over the penis 88-99%
Vaginal tampons structures used by ancient and medieval civilizations, may be accompanied by vinegar, hemlock, opium, honey which were used as spermicides % effectiveness unknown
		3) Surgical sterilization
Type Technique % effectiveness
Vasectomy - males tie off vas deferens 99.9%
Tubal ligation- females tie off Fallopian tubes 99.9%
Sterilization removal of gonads 100%
		4) Chemical
Type Technique % effectiveness
Douche with spermicide spermicide 70-85%
Oral contraception the pill, suppresses ovulation by releasing estrogen and progesterone derivatives, inhibits release of FSH and LH 95%-98%
Implants similar to pill, but it is am implant under the skin which gradually releases progesterone derivatives nearly 100%
Injections - Depo-Provera injection that lasts up to 3 months 99%
Lunelle injection that lasts up to 1 month 99%
		5) Irritant - IUD - probably acts as an irritant to prevent implantation, 
			95-99% effective, controversial because of many harmful side-effects reported
		6) Various web sites with comparisons of effectiveness of contraceptive techniques
			East Tennessee State University
			Oklahoma State University
			Southern Illinois University - nice overview
	C) Abortion (termination of a pregnancy) - definitions and methods
			a) Early in pregnancy (before 14 weeks)
					Vacuum aspiration - suction (6-9 weeks)
					D&C (dilation and curettage) - scraping the walls of the uterus (8-16 weeks)
					RU 486 - competes for progesterone receptors, disrupts
						communication between embryo (secretes HCG)
						and corpus luteum (5-7 weeks)
					MAP (Morning After Pill Links) - 
						also known as emergency contraception (90-95% effective at preventing pregnancy),
						pill is made up of large doses of synthetic hormones found in the
						birth control pill, estrogen alone, progesterone alone or estrogen and
						progesterone together (taken within 72 hours of intercourse)
					M&M - methotrexate interferes with mitosis, used with misoprostol (95% effective, taken 5-9 weeks)
			b) Later in pregnancy (after 14 weeks)
					D&E (dilation and evacuation) - fetus is surgically destroyed and removed (13-20+ weeks)
					D&X (dilation and destruction) destruction of the brain followed by removal
						referred to as the partial birth abortion (20-32+ weeks)
	D) Female Genitalia - External
			a) labia - equivalent to scrotum of male
			b) clitoris - equivalent of the male penis, swells during sexual arousal
	E) Female Genitalia - Internal
		1) Ovary - contains the eggs, site of beginning of meiosis - egg production
			a) females born with all the eggs they will use in a lifetime, oocytes
				develop within follicles in the ovary
			b) meiosis I produces secondary oocyte contained in follicle (follicle development)
			c) ovulation - release of secondary oocyte where meiosis is arrested,
				meiosis II begins only after stimulation by sperm during fertilization
		2) Fallopian tubes - catches eggs released from ovary during ovulation
			a) where most fertilizations occur
		3) Uterus - area of implantation of fertilized egg(s)
			a) lining is the endometrium, thickens during the end of female
				cycle in anticipation of implantation
		4) Cervix - entry into the uterus from the vagina
		5) Vagina - copulatory organ of females, receives penis and sperm after 
			ejaculation
		6) Hormonal control and the menstrual cycle and follicle development
			Ant. pituitary produces LH and FSH - stimulates development
				surge in LH and FSH cause ovuation - release of the egg/ovum from follicle
				ruptured follicle becomes the Corpus Lutem
			Corpus luteum secretes progesterone and estrogen to maintain lining
	F) Male - External genitalia
		1) Scrotum (scrotal sac) - houses testes outside the body)
		2) Testes, enclosed in scrotum outside of body, site of sperm production
			a) seminiferous tubules - where meiosis takes place
			b) 100 - 650 million sperm/ejaculation
			c) sperm structure - head (acrosome and nucleus), middle (mitochondrion)
				tail = flagellum
		3) Penis, copulatory organ, spongy erectile tissue, blood vessels
			a) Urethra - tube inside the penis that carries sperm and urine
	G) Male - Internal genitalia
		1) Ductus (Vas) deferens - connect testes to penis, squeeze sperm forward during 
			ejaculation
		2) Seminal Vesicles - secrete sugars for sperm (energy)
		3) Prostate Gland - secretes alkaline liquid which neutralizes acidic 
			environment in the vagina, stimulates activity of sperm
		4) Bulbourethral gland - secretes mucus for motility
		5) Semen - sperm + other chemicals mentioned above


II Fertilization, Development and Diseases

	A) Human Copulation
		1) 4 Phases
			Excitement
			Plateau
			Orgasm
			Resolution
	B) Coitus and fertilization
		1) Internal fertilization
				sexual arousal (penis in males and breasts, females - breast, labia, clitoris)
				coitus leads to orgasm, ejaculation in males
				sperm swims to egg in oviduct and fertilization begins,
				sperm contacts the egg and membranes fuse, exocytosis by the sperm
				releases its contents into the egg (acrosomal reaction), causes
				depolarization of the egg cell membrane = fast block to polyspermy
	C) Development
			1) zygotes undergoes mitosis 1 day after fertilization
			2) mass of cells becomes a blastocyst 5 days after fertilization
			3) implanation of blastocyst about 7 days after fertilization
			4) formation of the placenta (cells from embryo and mother)
			5) blastocyst produces HCG which stimulates corpus luteum to
				produce estrogen and progesterone
			6) Trimesters - result in growth, differentiation and morphogenisis
				1st Trimeseter - embryo grows, after 7 weeks becomes fetus
					mass of cells transforms into fetus with some working parts
					(e.g., kidneys), bone deposition, blood formation, external sex
					ograns develop
				2nd Trimeseter - significant increase in size, some reflexes and
					movement (e.g., thumbsucking and gripping)
				3rd Trimeseter - growth accelerates, baby becomes fatter, prepared
					for living independently
	D) Birth/Parturition
		Uterus begins powerful, rhythmic contractions - labor
		Initiated by increasing concentrations of estrogen, decreasing
			amounts of progesterone towards end of pregnancy
			oxytocin released by post. pituitary during labor
	E) Lactation
		Estrogen, Progesterone prepare breasts 
		PRL stimulates  maturity of the breasts and milk production
		PRL levels increase after parturition
		Oxytocin is released by tactile stimulation of the infant nursing on the breasts
	F) Sexually Transmitted Diseases (STDs)
		1) Herpes simplex II - viruses cause 2 types (oral and genital)
		2) Trichonomonas - protozoan causes burning and vaginal discharge
		3) Chlamydia - bacterium causes painful urination, can lead to
			arthritis, heart disease, and other symptoms in men
		4) Syphillis - bacterium, 3 stages (sores followed by rash followed by 
			invasion of the organ systems
		5) Gonorrhea - bacterium causes inflammation of reproductive tract,
			pelvis (PID), can spread to other parts of the body (heart, joints)
		6) AIDS - see Immune system

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