ASVAB General Science Test

The ASVAB general science subtest consists of 25 questions within 11 minutes. These questions cover both the biological and physical sciences. Below is a review of a portion of the biological and physical science content. Please take the time to review some material on this site on the ASVAB Test. You should average about 1 completed question per 30 seconds on this part of the ASVAB exam.

ASVAB Circulatory System Review

The cardiovascular system is vital for providing oxygen and nutrients to tissues and removing waste. The heart is divided into four chambers-two atria and two ventricles-that communicate through orifices on each side. The right atrium receives blood from the venous system and then lets blood fall down into the right ventricle. Blood then goes to the lungs for a new supply of oxygen. Then the blood comes back from the lungs and goes to the left atrium. It then falls into the left ventricle and is pumped into the general circulation. The heart is composed of three layers: epicardium, myocardium and an endocardium. Heart sounds are due to the vibrations produced by blood and valve movements. Blood pressure is the force exerted by blood against the insides of the blood vessels. Heart rate is determined by physical activity, body temperature, and concentration of ions. The heart is controlled by impulses from the S-A node which passes to the A-V node.

Hypertension, is characterized by elevated arterial pressure and is one of the more common diseases of the cardiovascular system. Arteriosclerosis is accompanied by decreased elasticity of the arterial walls and followed by narrowing of the lumen. Hormones can also play a large role in blood pressure regulation. The hormone aldosterone can promote retention of water in the kidneys and increased blood volume, which in turn increases blood pressure.

Blood is made up of approximately 45% hematocrit, and 55% plasma. Plasma is primarily water, however contains approx. 7% protein and 1.5 other substances. The proteins found in plasma are: albumin, globulin and fibrinogen. Hematocrit is made up of mostly red blood cells, but also white blood cells and platelets. Platelets can be key in blood clotting to form a plug.

The ASVAB general science section covers both biology and the physical sciences. The ASVAB test may cover the above material in multiple choice format. This section of the ASVAB test is extremely broad topic area.