Pulmonary Vein Development and Outflow Tract Septation Quiz

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What is the embryological origin of the interatrial (IA) septum?

The IA septum is formed by the septum primum and septum secundum.

What are some possible causes of the failure of proper development of the septum secundum or failure of closure of the ostium primum?

Some possible causes include chromosomal abnormalities, prematurity, low birth weight, prostaglandins, high altitude and low atmospheric oxygen tension, and hypoxia.

What is the most common congenital heart defect?

The most common congenital heart defect is a ventricular septal defect (VSD).

What is the embryological origin of the ventricular (IV) septum?

The IV septum is derived from the endocardial cushion (membranous) and walls of the primordial ventricle and bulbus cordis (muscular). Signup and view all the answers

What are the possible causes of a ventricular septal defect (VSD)?

A VSD can be caused by a defect in either the membranous or muscular portion of the IV septum, or by a failure of fusion of the membranous or muscular portions. Signup and view all the answers

What is the tetralogy of Fallot?

The tetralogy of Fallot is a combination of four heart defects: VSD, pulmonary artery stenosis, deviation of the aortic origin to the right (overriding aorta), and hypertrophy of the right ventricle (RV). Signup and view all the answers

What is the embryological cause of the tetralogy of Fallot?

The tetralogy of Fallot is caused by the unequal division of the conus cordis, resulting in the anterior displacement (malalignment) of the aorticopulmonary septum. Signup and view all the answers

What is the embryological cause of transposition of the great vessels?

Transposition of the great vessels is caused by the failure of the aorticopulmonary (conotruncal) septum to spiral. Signup and view all the answers

What is coarctation of the aorta?

Coarctation of the aorta is the narrowing of the aorta, usually distal to the origin of the left subclavian artery from the arch of the aorta. Signup and view all the answers

What are some possible causes of coarctation of the aorta?

Some possible causes include contraction of the ductus arteriosus and no clear cause. Signup and view all the answers

Describe the role of placenta in drug distribution.

The placenta acts as a barrier between the maternal and fetal capillaries and has tight endothelial cell junctions. It provides partial protection against drug transfer, except for lipid soluble drugs and unionised forms of weak acids and bases. Signup and view all the answers

What are the different fluid compartments in the body?

The body is divided into three major fluid compartments: extracellular fluid (15 liters), which includes plasma and interstitial fluids, and intracellular fluids (27 liters). The total body water is approximately 42 liters for a 70kg adult. Signup and view all the answers

What is the volume of distribution?

The volume of distribution (Vd) of a drug is the apparent volume required to account for the total amount of drug in the body divided by the blood plasma concentration of the drug. It is expressed in liters (L) or sometimes L/kg of body weight. Signup and view all the answers

Explain the single compartment model of drug distribution.

The single compartment model assumes rapid mixing of the drug in plasma and rapid equilibrium between drug in plasma and drug in extravascular tissues. It does not account for compartmentalization within the body. Signup and view all the answers

How does the volume of distribution (Vd) affect a drug's half-life?

The drug's half-life (t1/2) is directly dependent on the volume of distribution (Vd) and inversely dependent on the drug's clearance (CL) from the body. The equation for half-life is t1/2 = ln2 x Vd/CL. Signup and view all the answers

What is drug distribution?

Movement of a drug to/from blood and tissues of the body Signup and view all the answers

What factors affect drug distribution?

Cardiac output and blood flow, plasma protein binding, lipid solubility, degree of drug ionisation, pH of compartments, capillary permeability, and relative organ perfusion Signup and view all the answers

What is the role of cardiac output in drug distribution?

It affects the initial rate of distribution of drugs as it heavily depends on blood flow Signup and view all the answers

What is the significance of albumin binding in drug distribution?

Albumin is the predominant plasma binding protein and lipid-soluble drugs bind non-specifically to it Signup and view all the answers

What are the characteristics of drugs that may pass the blood-brain barrier?

They must be able to cross the physical and functional barriers of the blood-brain barrier Signup and view all the answers