Digestion
Respiration
Circulation
Excretion
Muscles
100

The rhythmic, wavelike muscular contractions that move food through the esophagus.

What is peristalsis?

100

The tiny, grape-like air sacs where the actual exchange of O2 and CO2 occurs.

What are alveoli?

100

These vessels contain one-way valves to prevent the backflow of blood as it returns to the heart.

What are veins?

100

The functional unit of the kidney responsible for filtering blood.

What is a nephron?

100

This type of muscle tissue is involuntary and found in the walls of internal organs like the stomach.

What is smooth muscle?

200

Produced by the liver and stored in the gallbladder, this substance emulsifies fats.

What is bile?

200

When this dome-shaped muscle contracts and moves downward, the thoracic cavity volume increases.

What is the diaphragm?

200

This chamber of the heart has the thickest muscular wall because it must pump blood to the entire body.

What is the left ventricle?

200

This hormone, released by the pituitary gland, increases the permeability of the collecting duct to water, reducing the amount of water released in urine.

What is ADH

200

Tough bands of connective tissue that attach muscle to bone.

What are tendons?

300

This carbohydrate-digesting enzyme is found in both saliva and pancreatic juices.

What is amylase?

300

This "flap" of cartilage closes over the trachea during swallowing to prevent choking.

What is the epiglottis?

300

Often called the "pacemaker," this cluster of cells initiates the electrical impulse for the heartbeat.

What is the SA (Sinoatrial) Node?

300

High-pressure filtration occurs in this "knot" of capillaries at the start of the nephron.

What is the glomerulus?

300

According to the "Sliding Filament Theory," these two protein filaments slide past each other during contraction.

What are actin and myosin?

400

This enzyme is secreted in the stomach and requires a highly acidic environment to break down proteins.

What is pepsin?

400

This protein molecule in red blood cells has four binding sites for oxygen.

What is hemoglobin?

400

These cellular fragments are essential for the blood clotting process (hemostasis).

What are platelets

400

This hormone is released by the adrenal cortex to increase sodium reabsorption, which in turn increases blood pressure.

What is aldosterone?

400

This ion must be released from the sarcoplasmic reticulum for muscle contraction to begin.

What is calcium?

500

These two specific enzymes, produced by the pancreas, are responsible for breaking down short-chain peptides into individual amino acids.

What are trypsin and chymotrypsin?

500

The specific term for gas exchange that occurs between the blood in the capillaries and the body's tissue cells.

What is internal respiration?

500

This specific type of white blood cell produces antibodies to target specific pathogens.

What are B-cells

500

The process by which glucose and amino acids are moved from the nephron back into the blood.

What is reabsorption (by active transport)

500

This high-energy molecule provides a quick source of phosphate to recharge ATP during intense exercise.

What is creatine phosphate?