Fetal development

Life begins with a new conception, 23 + 23 = 46 chromosomes Cleavage, mitosis cell division Implantation of the early embryo or blastocyst occurs at about 7 days, a few hundred cells Development at 4 Weeks https://www.webmd.com/baby/ss/slideshow-fetal-development All tissues are present, connective, epithelial, neural tube which will become CNS Developing the structures that will form face and neck. The heart and blood vessels continue to develop. Lungs, stomach, and liver start to develop. A home pregnancy test would show positive. Slide 4, 5th week post ovulation An opened oviduct with an ectopic pregnancy Anatomic features, including tail, limb buds, heart (which actually protrudes from the chest), eye cups, cornea/lens, brain, Blood cells now being produced Cardiac contractions began at 3 weeks Neural tube is closed 8 weeks Final week of the embryonic period Organogenesis in now complete Fetal period begins start of week 9 Eyelids and ears are forming, and you can see the tip of the nose. The arms and legs are well formed. The fingers and toes grow longer and more distinct. External genitals differentiate Heart has 4 contracting chambers Umbilical cord has one vein and two arteries Development at 12 Weeks Starts to make its own spontaneous movements. Top of the uterus can be felt above pubic bone. Elbows and knees have been bending since week 10 Heart beat may be heard on examination The sex organs of should start to become clear Development at 16 Weeks Mum can feel the top of the uterus about 3 inches below your belly button. The baby's eyes can blink and the heart and blood vessels are fully formed. The baby's fingers and toes have fingerprints. Development at 20 Weeks Between 17 and 20 weeks gestation, thalamo-cortical relays penetrate the cortex. 20 weeks gestation, pain receptors are present and linked. By 20 weeks gestation, the baby will respond to sound and move, wince, and recoil from sharp objects and incisions. Big stress hormone response since 18 weeks Uterus the level of the belly button. The baby can suck a thumb, yawn, stretch, and make faces. "quickening." Slide 14, 24 weeks Baby now and responds to sounds by moving or increasing their pulse. Mum may notice jerking motions if they hiccup. With the inner ear fully developed, the baby may be able to sense being upside down in the womb. Slide 15, Development at 28 Weeks Sleeps most of the time, clear sleep wake cycle by about 30 weeks Activity rapid eye movement sleep and the quiet resting state of non-REM sleep. Baby's First Dreams: Sleep Cycles Of The Fetus https://www.sciencedaily.com/releases/2009/04/090413185734.htm Evidence for early dreaming Slide 16, Development at 36 Weeks The brain has been developing rapidly. Lungs are nearly fully developed. The head is usually positioned down into the pelvis by now. Early term baby if born between 37-39 weeks Term, born at 39-40 weeks Late term 41-42 weeks