chapter 29 development and inheritance part 2

occurs after gastrulation and marks beginning of the formation of the nervous system

give rise to all sensory neurons, adrenal medullae, melanocytes of skin, cranial meninges, and skeletal and CT of head

primary vesicles

a series of paired, cube-shaped structures, develop from the mesoderm

myotome- develop into skeletal muscles, dermatome- form CT, including dermis, sclerotome- give rise to vertebrae and ribs

splanchic mesoderm- heart and visceral layer of serous pericardium, blood vessels, smooth muscle, and CT of respiratory and digestive organs, somatic mesoderm- gives rise to bones, ligaments, blood vessels, and CT of limbs

formation of blood vessels

process by which ectoderm, endoderm, and mesoderm develop into internal organs

1st arch- forms jaws, malleus, incus, 2nd arch- upper part of hyoid, stapes, 3rd arch- lower part of hyoid, 4th arch- thyroid and epiglottis cartilages, 5th arch- cricoid, arytenoid, and corniculate cartilages

otic placode- first sign of ear, lens placode- first sign of eye

hCG, relaxin, hCS

hCG- rescues corpus luteum from degeneration until the third or fourth month of pregnancy, progesterone/estrogen- maintain endometrium of uterus during pregnancy; help prepare mammary glands for lactation; prepare mothers body for birth of baby, relaxin- increases flexibility of pubic symphysis; helps dilate uterine cervix during labor, hCS- helps prepare mammary glands for lactation; enhances growth by increasing protein synthesis; decreases glucose use and increases fatty acid use for ATP production, prolactin- promotes milk production, oxytocin- milk ejection reflex

bringing of the fetus to birth (to deliver)

stage 1- stage of dilation, stage 2- stage of expulsion, stage 3- placental stage

stage 1 (stage of dilation)- time from the onset of labor to the complete dilation of the cervix; longest stage; rupturing of sac, stage 2 (stage of expulsion)- contractions force the fetal head into the cervix, stretching it; Stretch receptors cause release of more oxytocin, which in turn leads to stronger, more frequent contractions, stage 3 (placental stage)- 5-30 mins or more after delivery until the placenta or “afterbirth” is expelled by powerful uterine contractions

22 pairs of chromosomes that are not sex chromosomes

one chromosome in each pair came from the mother and the other from the father

determine specific traits or characteristic

homozygous- same alleles on homologous chromosomes, heterozygous- different alleles on homologous chromosomes