Cardiovascular System: Heart, Blood Vessels and Circulation (Pages 1–59)

Flashcards covering heart structure and function, blood vessels, double circulation, the cardiac cycle, heart rate control, CHD and related topics.

What are the four chambers of the heart?

Right atrium, left atrium, right ventricle and left ventricle.

What separates the heart into two halves?

The septum.

Which valves prevent blood flowing back into the atria?

The tricuspid valve (right) and the bicuspid/mitral valve (left).

What do the semi-lunar valves do?

They prevent blood from flowing back into the ventricles from the arteries.

What is the function of the coronary arteries?

They supply the cardiac muscle with oxygen and nutrients.

What is double circulation?

Two separate circulations: pulmonary (heart to lungs) and systemic (heart to the rest of the body).

Which vessels carry blood away from the heart?

Arteries.

Which vessels carry blood toward the heart?

Veins.

What vessels form networks between arteries and veins and enable exchange?

Capillaries.

How wide are capillaries and how do RBCs pass through?

About 8–10 micrometres in diameter; red blood cells pass in single file.

What is tissue fluid and how is it formed?

Fluid formed from blood plasma that bathes cells, formed by capillary walls.

Why is diffusion in capillaries efficient?

Short diffusion distance, concentration gradients, and a large surface area from many capillaries.

Where is the natural pacemaker of the heart located?

In the right atrium—the sinoatrial (SAN) node.

Which brain region controls heart rate?

The medulla oblongata.

How does adrenaline affect heart rate?

Adrenaline increases heart rate by acting on target cells in the heart.

How does carbon dioxide influence heart rate?

Sensors detect CO2 levels; medulla responds by increasing heart rate during exercise.

How is heart rate measured?

In beats per minute (bpm), often via counting the pulse.

What is coronary heart disease?

A condition where blocked or narrowed coronary arteries reduce blood flow to the heart muscle.

What causes atherosclerosis?

Plaques (fatty deposits) build up inside arteries, narrowing them and potentially forming clots.

What are common symptoms of CHD?

Chest pain, faintness, shortness of breath.

Name several risk factors for CHD.

Diet high in saturated fats/cholesterol, high blood pressure, smoking, lack of exercise, heredity.

What is the aorta?

The major artery that carries blood from the heart to the rest of the body.

What is the pulmonary artery and its job?

Carries deoxygenated blood from the heart to the lungs for gas exchange.

What is the pulmonary vein and its job?

Carries oxygenated blood from the lungs to the heart.

What is the vena cava?

A large vein that carries deoxygenated blood from the body back to the heart.

What is the hepatic artery?

Brings oxygenated blood from the aorta to the liver.

What is the hepatic portal vein?

Carries nutrient-rich blood from the intestines to the liver for processing.

What is the hepatic vein?

Carries deoxygenated blood from the liver to the vena cava.

What is the mesenteric artery?

Supplies blood to the intestines for nutrient absorption.

What is the renal artery and what does it do?

Renal artery carries blood from the aorta to the kidneys.

What is the renal vein and what does it do?

Renal vein carries blood from the kidneys to the vena cava.

What is capillary diffusion in tissues?

Oxygen and nutrients diffuse from blood into tissue fluid; wastes diffuse into blood.

How do arteries differ structurally from veins?

Arteries have thick, elastic walls and narrow lumens to withstand high pressure; veins have thinner walls, larger lumens and valves.

What are the stages of the cardiac cycle?

Atrial systole (atria contract), ventricular systole (ventricles contract), diastole (heart relaxes and fills).

Why is the left ventricle thicker than the right?

Because it pumps blood around most of the body, requiring more muscle.

What is a pulse?

A shockwave felt in an artery as the ventricles contract.