Circulatory System: Functions, Heart Types, and Blood Flow

What are the main purposes of the circulatory system?

To carry oxygen and nutrients to cells, remove carbon dioxide and wastes, transport hormones, regulate body temperature, and carry white blood cells for defense.

What is a simple transport system example?

Amoeba, which allows nutrients to diffuse in and wastes to diffuse out.

What is an open transport system?

A system where blood is pumped out of vessels and bathes the cells directly, as seen in lobsters and dragonflies.

What is a closed transport system?

A system where blood remains in vessels, allowing nutrients and wastes to diffuse between blood and body cells, as seen in frogs and humans.

What are the characteristics of a two-chambered heart?

Found in fish, it has slow circulation and mixes oxygen-rich and oxygen-poor blood.

What are the characteristics of a three-chambered heart?

Found in frogs, it has a mix of oxygenated and deoxygenated blood, which is a limitation for efficient circulation.

What are the characteristics of a four-chambered heart?

Found in humans, it has two separate high-speed pumps, preventing the mixing of oxygen-rich and oxygen-poor blood.

What is coronary circulation?

The blood supply to the heart itself, where blood leaves the heart chambers oxygen-rich and returns oxygen-poor.

What is pulmonary circulation?

The circulation of blood to the lungs, where blood leaves oxygen-poor and returns oxygen-rich.

What is systemic circulation?

The circulation of blood to the body, where blood leaves the heart oxygen-rich and returns oxygen-poor.

How is cardiac output calculated?

Cardiac output = Stroke volume x Heart rate.

What factors influence stroke volume?

The amount of blood returning to the heart, the size of the ventricles, and the strength of their contractions.

What role does the vagus nerve play in heart rate control?

It sends increased signals to slow down the heart rate.

What effect does adrenaline have on heart rate?

It causes the heart rate to increase.

What is a stress test?

A test designed to show how the heart responds to stress, typically involving exercise on a treadmill.

What is an angiogram?

A test that evaluates circulation quality and blockage in coronary arteries by injecting dye into the iliac vein.

What does an electrocardiogram (E.C.G / E.K.G) measure?

It measures electrical impulses created by the S.A node and A.V node in the heart.

What is the function of the S.A (Sinoatrial) node?

It controls the heart rate by sending signals and is known as the pacemaker.

What is the role of the A.V (Atrioventricular) node?

It amplifies the S.A node signal and transmits it to the ventricles, delaying the signal for proper contraction timing.

What is the significance of the pulse?

It indicates the surging of blood through an artery and can be used to monitor heart regularity, strength, and quality of circulation.

What does blood pressure measure?

The pressure blood exerts on artery walls, measured as systolic (maximum pressure during heart contraction) over diastolic (minimum pressure during relaxation).

What is the function of a stethoscope?

An instrument used to amplify sounds from the body, such as heart murmurs and lung sounds.

What is an echocardiogram?

An ultrasound of the heart that produces images to detect valve disorders and blood flow issues.

What is the Rh factor?

A protein marker on red blood cells; Rh positive has the antigen, while Rh negative has the antibody.

What complications can arise from Rh factor incompatibility during pregnancy?

An Rh- mother with an Rh+ baby may produce antibodies that can harm the baby's red blood cells, leading to anemia or brain damage.

What is the process of blood clotting?

Platelets release thromboplastin, which combines with prothrombin to form thrombin, leading to the conversion of fibrinogen into fibrin.

How do homeotherms regulate body temperature?

Through vasodilation to release heat when warm and vasoconstriction to conserve heat when cold.

What are Purkinje fibres?

Nerve fibres that carry the AV node signal to the bottom of the ventricles so the heart contracts from the bottom up.

What is the P-wave?

Electrical signal from the SA node causing atrial contraction.

What is the QRS complex?

The AV node amplifying and sending the signal to the ventricles.

What is the T-wave?

Recovery of the ventricles before the next beat.

What causes the "LUB" sound?

AV valves closing.

What causes the "DUB" sound?

Semilunar valves closing.

What is the normal pulse range?

54-90 BPM (athletes as low as 30 BPM).

What is a normal blood pressure?

About 120/80 (systolic/diastolic).

What is vasodilation?

Widening of surface blood vessels to release heat.

What is vasoconstriction?

Narrowing of surface blood vessels to conserve heat.

What is counter-current heat exchange?

Heat from arterial blood warms venous blood returning to the body's core.

What is the maximum safe heart rate?

About 200 BPM (above this = risk of heart failure).