Circulatory System Quiz

The circulatory system is responsible for transporting essential materials throughout the body via blood or plasma. These materials include oxygen, carbon dioxide, nutrients, hormones, antibodies, waste products, and heat.

Blood makes up approximately 8% of the human body and consists of two main components: plasma (the liquid part) and cells.

Plasma is the liquid part of blood that contains dissolved substances like proteins, electrolytes, and nutrients. It also carries waste products, hormones, and gases.

The cellular components of blood are: erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets. These cells are constantly being replaced by new cells produced in the bone marrow.

Red blood cells, also known as erythrocytes, are responsible for delivering oxygen to the body's tissues and carrying some carbon dioxide back to the lungs.

Each red blood cell contains millions of hemoglobin molecules, which bind to oxygen and carbon dioxide. Hemoglobin contains iron, which is essential for its function.

Anemia is a condition that results from a lack of red blood cells or hemoglobin. It can cause fatigue due to insufficient oxygen delivery to the body's cells.

Red blood cells have a unique biconcave disc shape. This shape increases their surface area to volume ratio, allowing them to efficiently pick up and release oxygen.

A specialized type of muscle tissue that makes up the heart. It has branched cells with connections between them, which allows for electrical signals to spread throughout the heart and coordinate contractions.

The natural ability of heart muscle to contract and relax without the need for nervous system stimulation.

The group of specialized cardiac muscle cells in the wall of the right atrium that initiates the heart's electrical signal.

The electrical signal generated by the SA node that spreads throughout the heart, triggering a heartbeat.

The phase of the cardiac cycle where the heart muscle contracts and pumps blood out.

The phase of the cardiac cycle where the heart muscle relaxes and refills with blood.

The small delay between the SA node's signal reaching the AV node and the ventricles contracting. This delay helps ensure the atria finish filling the ventricles before the ventricles contract.

The heart sounds that can be heard with a stethoscope. The 'lub' sound is caused by the closing of the atrioventricular valves, while the 'dub' sound is caused by the closing of the semilunar valves.

The region in the brain (specifically the medulla oblongata) that monitors the body's conditions and regulates heart rate.

The network of fibers that carry electrical signals from the AV node into the ventricles, triggering their contraction.

The number of heart beats per minute.

The increase in heart rate that occurs during exercise or other physical activity.

The contraction of both atria, followed by the contraction of both ventricles, in a single heartbeat.

The process of blood circulation in the body. It involves the heart pumping blood through arteries, veins, and capillaries.

A nerve that increases heart rate. It is located in the medulla and sends signals to the SA node, which controls the pace of heartbeats.

A nerve from the medulla to the SA node that slows down heart rate.

A hormone that increases heart rate and blood pressure. It is also known as adrenaline.

Rings of muscle that can tighten to restrict blood flow. They are found in the walls of arterioles.

Narrowing of blood vessels, caused by the constriction of sphincter muscles in arterioles. This reduces blood flow to a particular area.

Widening of blood vessels, caused by the relaxation of sphincter muscles in arterioles. This increases blood flow to a particular area.

A type of blood vessel that connects arterioles directly to venules. It can be used to bypass capillary beds and direct blood flow.

The system that transports oxygenated blood from the heart to the body and deoxygenated blood back to the heart.

The system that transports deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart.

A type of circulatory system in which blood passes through the heart once per circuit. This system is found in fish.

A type of circulatory system in which blood passes through the heart twice per circuit. This system is found in mammals.

A measure of the force applied to the artery walls by blood pressure. It has two components: systolic pressure and diastolic pressure.

The pressure when the heart contracts. This is the higher number in a blood pressure reading.

The pressure when the heart relaxes. This is the lower number in a blood pressure reading.

A condition where the arteries supplying the heart muscle become narrowed or blocked by fatty deposits called atheroma.