Sexual Intercourse Male Sex Act Erection Ejaculation Erection Erections are not caused by the contraction of skeletal muscle Erections are the engorgement of blood into three 3 columns of spongelike vascular space o These columns extend the length of the penis o Incur simultaneous activation of the nervous system Increase in parasympathetic stimulation rest and digest AND decrease in sympathetic inhibition fight or flight o Sympathetic inhibition promotes sexual arousal This creates vasodilation of arteries and compression of the veins Nitric Oxide NO Improves circulation Increase in cAMP Increase in cGMP Shuts down Ca2 channel Phosphate Less myosin fibers smooth muscle Vasodilation Relaxation muscle Less Ca2 Decrease PK activation Blood Engorgement Erection Ejaculation Increase in sympathetic stimulation of smooth muscle to deliver sperm to urethra The sphincter will contract to the bladder preventing flow of urine Urethra fills with sperm triggers skeletal muscles at the base of the urethra penis The muscles begin to contract this is known as the orgasm Contractions are generally in 0 8s intervals Males experience a refractory period afterwards While the refractory period varies widely among individuals ranging from minutes to days most men cannot maintain or achieve an erection during this time and many perceive a psychological feeling of satiation and are temporarily uninterested in further sexual activity the penis may be hypersensitive and further sexual stimulation may even feel painful during this time frame The increased pressure in the penis expels the semen filled with sperm Female Sex Act Sex Flush Tenting Same 2nd messenger pathway and neural controls as male but different location sexual arousal occurs throughout vagina External genitalia blood engorgement similar to erection Capillary dilation that will push fluids into vagina for lubrication and engorgement of the clitoris erection and labia Erection of nipples and enlargement of breasts due to filled capillaries Raising of uterus and lifting of cervix Upper 2 3 of the vagina become enlarged This increases the success of sperm deposition Females do not experience ejaculation but do experience orgasm Sex Flush Tenting Orgasm Fertilization Same skeletal muscle contraction as in males but little to no refractory period is experienced in females creating the possibility for multiple orgasms Know the following from the above image Zona Pellucida This structure binds spermatozoa and is required to initiate the acrosome reaction Acrosome contains enzymes needed to penetrate through the outer membrane of the oocyte the head of the sperm is also the location of the DNA Midpiece of sperm The midpiece has a central filamentous core with many mitochondria spiralled around it used for ATP production for the journey through the female cervix uterus and uterine tubes Syngamy the fusion of two gametes in fertilization Morulla A solid ball of cells resulting from division of a fertilized ovum and from which a blastula is formed In the above image know the pathway the egg travels Ovum Frimbriae peristalsis Ampulla fertilization usually occurs here Isthmus Uterus Use the acronym below to memorize the order Our Friends Are In Uzbekistan Pregnancy Complications Ectopic Pregnancy In a normal pregnancy a fertilized egg travels through a fallopian tube to the uterus The egg attaches in the uterus and starts to grow But in an ectopic pregnancy the fertilized egg attaches or implants someplace other than the uterus most often in the fallopian tube This is why it is sometimes called a tubal pregnancy Tubal Pregnancy Lethal to mother pregnancy must be terminated or mother will die from hemorrhaging Abdominal Pregnancy morula implants in abdomen abdominal pregnancies can go to term but must be delivered by C Section Placenta The organ of exchange between maternal and fetal blood Interlocking fetal and maternal circulations Exchanges are made between the fetal and maternal blood before the fetal blood leaves through the umbilical vein and maternal blood exits through the maternal venules The placenta performs the functions of the following even though the fetus has these organ systems However within the uterine environment these organs cannot function Digestive System Respiratory System Kidneys Acts as a temporary Endocrine System Secrete HCG hormone to maintain corpus luteum Increase progesterone increase testosterone increase estrogen Pregnancy and Birth Parturition the process of birth 1 After 6 or 7 months of gestation last trimester begins the amount of estrogen increases and the amount of progesterone decreases 2 This change in hormonal balance results in an increase in gap junctions in the uterine wall myometrium gap junctions Gap junctions are the proteins that connect cell membranes and facilitate uterine contractions The increased number of gap junctions also increases the frequency of uterine contractions 3 Braxton Hicks Contractions Braxton Hicks contractions are a tightening of the uterine muscles for one to two minutes and are thought to be an aid to the body in its preparation for birth Not all expectant mothers feel these contractions They are weak untimed irregular or infrequent and slow 4 The posterior pituitary gland releases oxytocin which promotes uterine contractions and lactation 5 Prostaglandin is synthesized within the human fetal membranes and acts to ripen the cervix change membrane structure and promote the contraction and relaxation of smooth muscle This process is important to parturition as the prostaglandin causes the myometrium middle wall of uterus to contract 6 Water breaks due to the weight of the baby The contractions of the uterus push the baby s head against the cervix stretch receptors signal the hypothalamus of the mother to release more oxytocin which increases the contraction strength and frequency and pushes the baby s head harder against the cervix creating a positive feedback cycle Body s Response to Pregnancy 1 The weight of the uterus starts at about 50g and ends at about 1100g 2 Breasts double in size and weight During pregnancy the hormone progesterone readies the breasts to produce milk The breasts grow larger due to additional fat and swollen milk glands 3 Average weight gain is 24 lbs distributed as follows a 7 Fetus b 4 amniotic fluid placenta c 2 uterus d 2 breast e 6 blood f 3 fat storage 4 BMR Basal Metabolic Rate is the amount of energy expended daily by humans and other animals at
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