BISC 307L 1st Edition Exam 3 Study Guide I CALCIUM BALANCE 1 What are the two forms that calcium exists in in the body and which is more abundant 1 Calcium phosphate 99 which forms the mineral part of bones and is the storage pool of calcium 2 Ca2 1 for intracellular signaling contraction adhesion in tight junctions cofactor for blood coagulation 2 What are the three hormones that regulate calcium balance 1 Parathyroid hormone raise plasma Ca2 o released from parathyroid glands essential for life 2 Calcitriol VITAMIN D3 raises plasma Ca2 o made from Vitamin D in liver and kidney converts is to calcitriol o 1 Raises absorption in small intestine of calcium o 2 Stimulates bone reabsorption 3 Calcitonin Lowers plasma Ca2 o from C cells in thyroid o Counteracts effects of PTH and inhibits calcium reabbsorption in kidney o Needed for children and for women in pregnancy 3 Be able to describe what is going on in the calcium balance diagram Start with the small intestine 1 Small intestine is source of new calcium will either stay in intestine and be excreted or is absorbed into tissue 2 On the left is bone reservoir for calcium which can be take n from ECF and deposited into bone 3 On the right is the kidney where calcium is filtered and be reabsorbed or put back in ECF 4 What is the difference between osteoblasts and osteoclasts OsteoBLASTS bone deposition OsteoCLASTS break down bone and liberate calcium 4 What are the three ways the parathyroid hormones raise plasma calcium levels 1 Strongly stimulate bone reabsorption freeing calcium 2 Reabsorption of calcium back into the blood by kidney lowers plasma phosphate 3 Indirectly stimulates synthesis of calcitriol II SEXUAL REPRODUCTION 1 What are the three important ells in the undifferentiated gonads and what do they turn into under the influence of Y and absence of Y chromosome 1 Germ cell spermatogonia in males oogonia in females 2 Coelomic epithelium sertoli cell in male granulosa in female 3 Mesenchyme leydig cell in male theca cell in female 2 Briefly describe the endocrine control of sexual maturation starting with the hypothalamus Hypothalamus releases GnRH 2 cells in Ant Pit release LH and FSH gonadotropins stimulate growth of gonads testes and ovaries which secrete progesterone and estradiol as well as inhibins and activins activate or inhibit FSH secretion from ant pit 3 What is the time course of testosterone secretion for males Testes secrete testosterone during fetal life but stop at time of birth because starts to depend on gonadotropins which are not existent 10 13 year period of no secretion puberty testes become active hypothalamus secretes more GnRH Pulses of LH and FSH secreted 30 40 years is the climacteric and spermatogenesis gradually declines for decades 4 What are the two ways to maintain testes temperature 1 Counter current heat exchanger o arrangement of vessels to the testes in which veins wrap around incoming artery returning blood warmed and descending blood cooled 2 Constant adjustment of pulling the scrotum closer due to spinal reflex with temperature sensitive nerves 5 What is important about the cervix opening between the uterus and vagina that locks with an acidic mucus plug and acts as a barrier to sperm penetration and bacteria It is degraded when the female is preparing for sperm to enter 6 Briefly describe the pathway of the ovarian follicle development Primary follicle secondary follicle needs FSH to continue only some do oocyte antrum pressure builds and estradiol secreted meanwhile outside tissue is being digested mature graffian follicle expelled into the abdomen ovulated oocyte with ruptured follicle corpus luteum produces estradiol and progesterone regressing corpus luteum corpus albicans because not enough LH and FSH support stroma 7 Describe the main phases of ovarian and menstrual cycles but be able to describe in depth 1 Follicular phase onset of menstruation o FSH and LH pretty normal to low o Estrogen Has been falling from corpus luteum degenerating but now starts to rise because follicle growing o Progesterone has been falling due to degeneration of corpus luteum and still stays low o Inhibin secreted by granulose cells so has same progression as estrogen 2 Ovulation o levels of estrogen now fall because the cell has been released Inhibin is high Levels of FSH and LH very high Day 14 3 Luteal Phase o dominated by corpus luteum which is secreting estrogen and progesterone and inhibiting levels of FSH and LH o regresses after 10 days unless it has support from fertilized egg 8 Describe the progression of the endometrium throughout the menstrual cycle 1 Menses the endometrium which had grown has been degenerating due to a lack of progesterone and estradiol secretion causing bleeding vasoconstriction relaxes 2 Proliferative phase Rising levels of estrogen causes it to double in thickness and the cervical plug becomes easier for sperm to penetrate 3 Secretory phase Growth slows but gland vascularization increases preparing body should fertilization occur 9 Briefly describe the process of fertilization and implantation 1 Day 1 Fertilization o outer 1 3 of oviduct ampulla period of potential fertilization 6 days before ovulation and one day after 2 Day 2 4 o division of egg after fertlization to form morula still in oviduct necessary for proliferation of endometrium arrives in uterus and becomes blastocyst 3 Day 4 5 o Outer layer of blastocyst implants and inner layer becomes embryo 10 What are the 2 changes the sperm must go through upon entering the vagina 1 Capacitation more motile due to something in uterus 2 Activation burrow when get close to egg 11 What are the three main differences of fetal circulation than adult circulation 1 Ductus venosus blood through liver from umbilical vein deoxygenated fuses with partially oxygenated blood to the right atrium 2 Right atrial blood bypasses fetal lungs and instead goes to left atrium where FORAMEN OVALE hole and can leave through ductus arteriosis 3 Fetal hemoglobin has different subunit with high affinity for oxygen 12 What happens to circulation when the baby is born Lungs expand causes decreased vascular resistance so blood flows blood oxygenated in lungs so blood returns with oxygen drop in pressure on right side so left pressure is higher causing opposite pressure gradient septum formed from foramen ovale ductus arteriosis sensitive to oxygen so seals off ductus venosus also seals off 13 What happens during parturition 3rd trimester