foetal and neonatal physiology

Question 1

capacitation

Answer 1

-conditioning of sperm occuring in the female reproductive tract
-removal of glycoprotiens and seminal fluid protein from plasma membrane overlaying acrosome
1-3) Acrosomal reaction allowing sperm penetration through the corona radiata and zona pellucida
4) Fusion of oocyte and sperm plasma membranes which is a cortical reaction
5) sperm nucleus englufed by oocyte cytoplasm

Question 2

pregnancy tests

Answer 2

detect human chorionic gonadotrophin (HCG) a hormone produced by trophoblast tissue
- prolongs oestrogen and progesterone
-signals endometrium

Question 3

ectoderm, mesoderm and endoderm

Answer 3

ectoderm- structures that maintain contact with the outside world e.g. ear, nose and hair
mesoderm- vertebral column
endoderm- GI tract, bladder ;and urethra

Question 4

how is the trilaminar disc formed

Answer 4

gastrulation- forms multiple layers of cells from blastula which has a single layer
neurulation- nuetral plate bends and fuses to make a hollow tube to form the CNS
organogenesis
somitogenesis- segmentation of mesoderm to make somites, balls of mesoderm which make bone, cartilage, muscle and tendons

Question 5

4-6 weeks

Answer 5

the product of conception ensures its own survival
- prevents shedding of endometrial wall and promotes endometrial growth
- implantation
- uses resources from pre-prepared endometrium
- shields itself - develops a placenta
- invokes drastic changes in the maternal physiology

Question 6

10 week

Answer 6

to ensure its own survival
- uses hosts resources when readily available
- diverts hosts resources even at the expense of the host
- protects itself - shielded from possible harmful changes within the host

Question 7

foetus heart beat

Answer 7

heart beats during the 4th week after fertilization with a heart rate of 65 beats per minute
reach’s 140 beats per minute just before birth

Question 8

circulation of the heart

Answer 8

the left side of the heart transports blood to the body and placenta then back to the left heart and to the right hand side of the heart as well as the lungs following to the left heart and lungs following out of the right side of the heart and then to the placenta

Question 9

foetal circulation

Answer 9

as the lungs, liver, kidney and GIT are not fully functional in intrauterine life, they have a low blood supply. in contrast, the placenta has a rich blood supply so the differences are
umbilical venous and abdominal portal blood pass through the ductus venosus bypassing the liver
after the birth portal blood still goes through the ductus venosus contacts.
most blood from the inferior vena cava enters the RA and straight into the LA via the foramen ovale, this takes blood into the RA and after brith, pressure is more in the LA. the septum primum closes against the septum secundum preventing blood to go back.
deoxygenated blood enters the RA via the superior vena cava and goes to the RV through tricuspid valve and is then pumped into the pulmartery mostly going to the aorta via ductus arteriosus

Question 10

O2 diffusion

Answer 10

maternal sinus blood passes to foetal blood by simple diffusion foetal hemoglobin for O2 and foetal hemoglobin concentration is 50% more than maternal level

Question 11

divisions of the GI tract

Answer 11

foregut- mouth - bile duct opening into duodenum
midgut - bile duct opening - 2/3 transverse colon
hindgut - transverse colon- anal canal

Question 12

placenta

Answer 12

nutrition and O2 for foetus
removal of waste products and co2
hormone production
foetal protection