29:pregnancy Flashcards
What hormone stimulates egg maturation within ovarian follicles?
When does the hormone luteninzing occur in menstrual cycle?
Follicle stimulating hormone
11-13 days, ovulation follows 36-48 hours later
3 ways sperm is classified?
Non-motile
Progressively motile (swims forward)
Non-progressively motile ( sperm swims in tight circles)
What is motility influenced by? (8)
Stress Semen ph Caffeine Alcohol Zinc Folate Nicotine Low vitamin c
Increased estrogen levels prior to ovulation can result in what?
Reduced stickiness of cervix so sperm can move through the uterus and fertilization can take place in the Fallopian tubes
Name the 3 parts sperm is consisted of?
Head ( contains acrosome, stores hydrolytic enzymes= breakdown cell membrane in vagina) contains a nucleus which stores dna
Mid piece ( contains mitochondria for energy)
Tail ( provides motility)
Capacitation
What happens when sperm cell binds to glycoproteins of the zone pellucida?
Uterine secretions break down the sperm cell membrane to a thin layer
Acrosomal enzymes are released, they breakdown the wall of the zona pellucida so the sperm can penetrate the egg
What happens upon entry of the sperms head (nucleus)?
Increased calcium ions produce inhibiting enzymes that prevent other sperm to enter the oocyte, what is this called?
Calcium ions are released in eggs cytoplasm
Slow block to polyspermy
Blastocyst
What are 2 components of blastocysts?
Pre- embryo stage consists of 100-120 cells
Trophoblasts (form placenta)
Inner mass cells (embryoblast) become embryo, they are also pluripotent ( will become any tissue or cell via hox genes)
What are implanted blastocyst covered by?
When is implantation completed?
Human chorionic gonadotropin (Hcg)
Endometrial cells
12th day after ovulation
Hormone Secreted by trophoblasts cells (tells whether u are preggo)
By 12 weeks Hcg levels drop, what replaces it?
How is placenta formed?
What are the embryonic tissues that help form the placenta?
Placenta starts releasing estrogen and progesterone
From tissues of the embryo and mom
Chorion (covers fetus)
Chorionic villi
Amnion (Extraembryonic membrane)
Functions of amnion? (3)
Where does amniotic fluid come from?
Form a clear sac filled with amniotic fluid
Provides fluid environment protects embryo
Maintain homeostasis
Freedom of movement, keep other parts from rubbing together
Maternal blood, later fetal urine
Name the 3 remaining extraembryoic membranes?
Yolk sac( blood cell and blood vessel formation, 1st to develop, forms into digestive tube)
Allantois( umbilical cord, becomes part of urinary bladder)
Chorion (outer layer, forms placenta, encloses embryo body and membranes)
Gastrulation
Name 3 germ layers?
Form body organs and system
Ectoderm- (nervous system(brain/spinal cord)sense organs.(eyes,ears,nose), skin)
Endoderm- (forms GI tract, respiratory & urinary systems)
Mesoderm- muscles and bones
Name 3 fetal shunts.
- ductus arteriosus (found in heart, bypass lungs)
Formane ovale( bypass lungs)
Ductus venous (found in liver, bypass liver)
Chadwick’s sign
Cholasma
Vagina develops purplish hue
Pigmentation of facial skin may increase
