ASVAB General Science

Macronutrients

Larger compounds from which we derive the calories, or energy, necessary to sustain life functions

Carbohydrates

Immediate and readily accessible energy. These molecules are ultimately broken down into glucose and circulated through the blood to support metabolic functions

Lipids

The body converts and stores unused carbohydrates as fats. These function as the source material for hormones and also serve as an energy source

Protein

Necessary for cellular growth, repair, and transport. Made up of amino acids

Micronutrients

Consists of those vitamins and minerals required by the body to function properly. Only required in small amounts; however, if adequate amounts are not acquired, overall health is potentially compromised and long term issues may arise.

Vitamins

There are numerous found throughout the body, all with different purposes, to allow for normal cellular function.

Two types of proteins

Fat-soluble (such as A, D, E, and K) are present in foods with fats and do not dissolve in water. Water- soluble (such as B vitamins) are dissolved in water and carried around the body, but not stored.

Minerals

Found in food that we consume and are essential for cells to function properly. Common ones are magnesium, potassium, sodium, and calcium.

Nutrition related diseases

Those which arise from either the deficiency or the excess of a micro or macronutrient. Common examples are diabetes, hypertension, scurvy, and iron-deficiency anemia

Skeletal System

Collection of bones, composed of a very hard and inflexible phosphate, and cartilage, composed of spongy, flexible collagen. It functions as structural support and protection for muscles and organs, as well as facilitating locomotion.

Where is blood created?

Inside of bone marrow

Muscular System

Works in conjunction with the skeletal system to facilitate motion. Made up of three types of muscle: cardiac, skeletal, and smooth muscle.

Three types of muscles

Cardiac muscle: Makes up the heart and is involved in regulating contraction and relaxation of the heart

Skeletal muscles: Those connected to bone that enable motion.

Smooth muscle: Lines organs and aids in digestion.

Respiration

Exchanging of gases between one’s internal and external environment

Respiration- Oxygen

Cellular respiration can occur with or without oxygen. In aerobic processes, oxygen is converted into energy in the form of ATP. In human respiration this is the gas that we inhale.

Respiration- Carbon dioxide

The gas that oxygen is exchanged for in respiration and therefore the gas that we exhale.

Respiration- Water vapor

This is the gas phase of water. It occurs as liquid water is evaporated or solid water (ice) undergoes sublimation.

Nasal cavity

Air-filled space behind the nose

Pharynx

Also known as the throat, it is the structure behind the nose and the mouth that connects them to the esophagus. Its main function is to receive and allow for the transmission of air to the lungs and food to the stomach

Epiglottis

This is the flap behind the tongue that ensures that air goes to the lungs and food goes to the stomach

Trachea

Also known as the windpipe, it is a passageway for air to get moist and warm as it makes its way to the lungs

Bronchi

The trachea branches into the left and right bronchi. The bronchi are responsible for transporting air that has come through the windpipe to the lungs.

Bronchioles

Also known as “little bronchi”, these are smaller branches that the left and right bronchi divide into

Alveolus

These are tiny air sacs that branch off from the bronchioles where gas exchange occurs in the lungs

Capillaries

These are tiny blood vessels that serve as a connection point between arterioles and venules, allowing nutrients to be transferred between blood and tissues

Diaphragm

Skeletal muscle that sits below the lungs. As you inhale, it contracts and flattens to allow your lungs to fill with more air. As you exhale it relaxes so air can be pushed out of the lungs.

Circulatory system

Responsible for the transport of blood and nutrients throughout the body

What makes up the circulatory system

Arteries, veins, capillaries, the lungs, the heart, the brain, and the kidneys.

Heart

Pump oxygenated blood to the body and deoxygenated blood to the lungs to become oxygenated

Blood

Consists of red blood cells, which facilitate oxygenation, white blood cells, which aid in immunologic defense, plasma, which is the liquid medium inside of the circulatory system, and platelets, which also aid in defense

Atrium/atria

The two receiving chambers of the heart. They appear on both the left and right sides of the heart above the ventricles.

Ventricles

The two pumping chambers of the heart. They appear on both the left and right sides of the heart below the atria.

Vena cava(e)

There are two vena cavae in the heart: superior and inferior. The superior vena cava drains the upper part of the body while the inferior vena cava drains the lower half of the body. Both of these dump deoxygenated blood into the right atrium.

Pulmonary artery

Responsible for carrying deoxygenated blood from the heart to the lungs

Pulmonary vein

Responsible for carrying oxygenated blood from the lungs to the heart

Aorta

The largest artery in the body. Oxygenated blood will leave the heart through the aorta to be sent throughout the whole body

Artery

A a blood vessel that carries blood away from the heart. Typically carry oxygenated blood with the exception of the pulmonary artery, which carries deoxygenated blood.

Arterioles

Also known as “little arteries.” Small branches off the arteries that connect arteries to capillaries

Vein

Blood vessel that carries blood toward the heart. Typically carry deoxygenated blood with the exception of the pulmonary vein, which carries oxygenated blood

Heart valves

Bicuspid (mitral) valve, tricuspid valve, aortic valve, and pulmonary valve

Venules

Also known as “little veins”, these are small branches off the veins that connect veins to capillaries

Heart diseases

Also known as cardiovascular diseases. They stem from difficulties in pumping blood throughout the body by way of arterial blockage, high blood pressure, and other issues.

Blood types

Four main blood types: A, B, AB, and O. These blood types are dependent on the antigens present on one’s red blood cells (also known as erythrocytes). Each blood type is also classified as either positive or negative depending on if the Rhesus (Rh) factor is present or not.

Antigens

These are what the cells recognize as “self”. For example, if someone has a blood type A, they will have A antigens on the surface of their red blood cells. If they have AB blood, then they will have both A and B antigens. O blood is the absence of any antigens

Rh factor

An inherited protein that is found on the surface of red blood cells. Presence of this protein makes you Rh positive, and absence of this protein makes you Rh negative

Universal donor

Someone who can donate blood to someone with any blood type. The universal blood donor is blood type O since there are no antigens on the surface of its cells

Universal recipient

Someone who can receive blood from someone with any blood type. The universal blood recipient is blood type AB since there are both A and B antigens on the surface of its cells

Digestive system

Functions to break food down into usable micro and macronutrients. Begins upon ingestion of food

Saliva

Contains enzymes that begin breaking down food

Mastication

Also known as chewing. Helps reduce food to a bolus that is easy to swallow

Small intestine

Primarily serves to absorb the nutrients from the chyme before passing it on to the large intestine (colon)

Large intestine

Further absorption of nutrients and water takes place, before passing the remaining matter, termed feces, to the rectum where it is excreted

Kidneys

Function to remove waste from the bloodstream through a filtration system resulting in the production of urine

Lungs

In addition to providing oxygenated blood, they also remove carbon dioxide from the blood

Skin

Organ through which perspiration (sweat) is released. It plays a minor role in excretion; its primary role is temperature regulation.

Salivary amylase

Enzyme found in the mouth that is responsible for the initial breakdown of starches from complex carbohydrates to monosaccharides

Gastric acids

Also known as stomach acid, it is the acidic fluid within the stomach. The pH of the stomach lies between 1 and 3 and is essential for activating digestive enzymes as well as breaking down proteins

Pepsin

Enzyme found in the stomach that breaks down proteins into polypeptides

Pancreas

Organ found below the liver. One of its main functions is to produce enzymes that break down food into a usable form for our body

Pancreatic enzymes

Lipase: responsible for breaking down fats.

Pancreatic amylase: responsible for breaking down starches

Trypsin: allows for the digestion of protein

Liver

Large organ that is situated on the right side of the abdomen. It serves as producer of bile, metabolizer of nutrients, and an enzyme activator. It also helps with the excretion of drugs and hormones

Bile

Green-brown fluid that is produced in the liver and stored in the gallbladder. It functions to carry wastes away and break down fats.

Nervous system

Enables communication between cells throughout the body

Major components of the nervous system

The brain, the spinal cord, and neurons, or nerve cells

Brain

The central information processing unit of the body. It is composed of many billion neurons and it is where information received by the senses is processed

Parts of the brain

The brain contains two hemispheres (left and right) and three major parts: the cerebrum, the cerebellum, and the brain stem

Cerebrum

Largest portion of the brain, responsible for numerous things such as (but not limited to) speech, judgment, problem-solving, and emotions

Cerebellum

Aids in balance and coordination

Brainstem

Connects with the spinal cord and regulates involuntary movements such as breathing and digestion

Neurons

Contain a nucleus and long branches that extend to other neurons. Chemical signals pass from one neuron to the next to transmit information

Spinal cord

Connects the brain to the rest of the body. It is a bundle of nerves that runs vertically through the spine that branches throughout the body. Signals received by the senses travel through the spinal cord to be processed in the brain

Peripheral nervous system

Collection of nerves residing outside of the central nervous system, coordinating voluntary and involuntary movement