FOM week 3 part 2 Flashcards
What is fertilization?
The fusion of sperm and oocyte to form a zygote, occurring in the ampulla of the uterine tube.
What happens when sperm binds to the zona pellucida (ZP3)?
Acrosomal enzymes are released to penetrate the egg, and meiosis II is triggered in the egg.
What prevents further sperm entry after fertilization?
The egg’s membrane fuses with the sperm, blocking additional sperm entry.
What is cleavage in embryonic development?
Rapid cell divisions.
What is totipotency, and up to which stage are cells totipotent?
The ability to develop into any cell type; cells are totipotent up to the 8-cell stage.
What is mosaicism?
A condition where an individual has cells with different chromosome complements.
What is a morula?
An early embryo with 16-32 cells.
What is a blastocyst?
An embryo with 200-300 cells and a fluid-filled cavity (blastocyst cavity).
What do trophoblasts and embryoblasts form?
Trophoblasts form the placenta; embryoblasts form the embryo.
When does implantation occur?
Around day 6 after fertilization.
What is ectopic pregnancy?
Implantation outside the uterus.
What is placenta previa?
Abnormal positioning of the placenta.
What are the two layers of the bilaminar embryo?
The epiblast (dorsal) and hypoblast (ventral).
What is the role of the syncytiotrophoblast?
It produces hCG and helps with implantation.
When is the amniotic cavity formed?
By day 9.
What is gastrulation?
The process of forming three primary germ layers from the epiblast.
What are the three germ layers and their derivatives?
Ectoderm: Skin, hair, nervous system. Mesoderm: Axial skeleton, muscles, urogenital systems, cardiovascular system. Endoderm: Lining of gut, respiratory tract, bladder, and urethra.
What are the key roles of cholesterol?
Maintaining cell membrane structure, forming lipid rafts, and serving as a precursor for bile acids, vitamin D, and steroid hormones.
What are the key roles of triglycerides?
Energy storage and contributing to cell membrane structure.
How are lipids transported in the bloodstream?
Via lipoproteins, which protect hydrophobic lipids in the aqueous environment.
What is atherosclerosis?
Hardening of arteries due to plaque buildup.
What are LDL and HDL, and how do they differ?
LDL (‘bad’ cholesterol): Contributes to plaque formation. HDL (‘good’ cholesterol): Helps reverse cholesterol transport and protects against cardiovascular diseases.
What are the steps in atherosclerosis formation?
- Endothelial injury. 2. Leukocyte infiltration. 3. Smooth muscle cell and WBC accumulation. 4. Plaque formation with a fibrous cap. 5. Vessel occlusion due to cap digestion and clot formation.
How do statins help in atherosclerosis?
Statins reduce LDL cholesterol, inhibit smooth muscle migration, and prevent platelet and leukocyte adhesion.
What is the impact of statins according to trials?
Statin therapy reduces cardiovascular events by 25-30%.
What is blood pressure (BP)?
The outward force exerted by blood on the walls of blood vessels.
What are systolic and diastolic BP?
Systolic BP: Pressure during heart contraction (~120 mmHg). Diastolic BP: Pressure during heart relaxation (~80 mmHg).
How is mean arterial pressure (MAP) calculated?
MAP = [(2 x Diastolic) + Systolic] / 3.
What is hypertension?
Clinic BP ≥ 140/90 mmHg or daytime average ≥ 135/85 mmHg.
What is hypotension?
BP < 90/60 mmHg.
What is the formula for MAP?
MAP = Cardiac Output (CO) × Systemic Vascular Resistance (SVR).
What is the relationship between CO and HR?
CO = Stroke Volume (SV) × Heart Rate (HR).
What are the effects of increased BP?
Decreased HR and SV.
