The Circulatory System Review

Comprehensive practice questions covering the components, functions, and diseases of the human circulatory system based on lecture notes.

Why do living organisms need a circulatory system?

To take nutrients and oxygen to cells for growth and cellular respiration, and to remove waste products like carbon dioxide before they become toxic.

What are the three main components of the circulatory system?

The heart, blood vessels, and blood.

What is the function and composition of blood plasma?

It is the liquid part of the blood ($55\%$) that acts as a suspension medium to transport dissolved substances such as oxygen, carbon dioxide, salts, and sugars.

What are the characteristics and function of Red blood cells (erythrocytes)?

They are disc-shaped (biconcave) cells with no nucleus, formed in bone marrow, and contain haemoglobin to transport oxygen and carbon dioxide.

What are the characteristics and function of White blood cells (leucocytes and lymphocytes)?

Large, irregularly shaped cells with a nucleus that protect the body against diseases by producing antibodies or engulfing and destroying germs.

What is the primary role of blood platelets (thrombocytes)?

They are small cell fragments produced in the bone marrow that play an important role in blood clotting.

How do arteries differ from most other blood vessels in terms of direction and pressure?

Arteries take blood AWAY from the heart under high pressure; they have thick, muscular walls to withstand this pressure.

Which artery is the only one that transports deoxygenated blood?

The pulmonary artery, which takes blood from the heart to the lungs.

What is the function of valves in veins?

To ensure that blood flows in only one direction toward the heart, as veins are under lower pressure.

What are the structural features and functions of capillaries?

They have walls only one cell thick, allowing for the easy diffusion of oxygen, nutrients, wastes, and carbon dioxide between the blood and the cells.

Define 'oxygenated blood' and 'deoxygenated blood' as used in the circulatory system.

Oxygenated blood is high in oxygen and low in carbon dioxide; deoxygenated blood is low in oxygen and high in carbon dioxide.

Where is the heart located in the human body?

Just above the diaphragm in the chest cavity, between the two lungs and behind the sternum (breastbone).

What are the four chambers of the heart?

The two upper chambers are the right and left atria, and the two lower chambers are the right and left ventricles.

What is the function of the septum in the heart?

It is a muscular wall that separates the right and left sides of the heart.

Match the heart valves to their specific locations.

Tricuspid Valve (between right atrium and ventricle); Bicuspid valve (between left atrium and ventricle); Aortic Valve (between left ventricle and aorta); Pulmonary Valve (between right ventricle and pulmonary artery).

What is the difference between pulmonary circulation and systemic circulation?

Pulmonary circulation moves blood from the heart to the lungs and back; systemic circulation moves blood from the heart to the rest of the body and back.

Trace the path of deoxygenated blood starting from the Vena Cava.

Vena Cava $\rightarrow$ Right Atrium $\rightarrow$ Right Ventricle $\rightarrow$ Pulmonary Artery $\rightarrow$ Lungs.

Trace the path of oxygenated blood starting from the pulmonary vein.

Pulmonary Vein $\rightarrow$ Left Atrium $\rightarrow$ Left Ventricle $\rightarrow$ Aorta $\rightarrow$ Body cells.

What is hypertension and what can it lead to?

High blood pressure where the heart works harder than normal; it can lead to heart attacks, kidney damage, and strokes.

What causes a heart attack?

Narrowing or blockage of coronary arteries (due to blood clots or cholesterol) which prevents oxygen and nutrients from reaching the heart muscle, causing it to die.

What is a stroke and what are common symptoms?

A condition caused by a blocked or burst blood vessel in the brain; symptoms include confusion, paralysis on one side of the body, and inability to speak.

How does nicotine from smoking affect the circulatory system?

It causes blood vessels to constrict, which increases heart rate and blood pressure, causing a work overload that can enlarge the heart.