Circulatory System Quiz

Circulatory System

• The circulatory system is an organ system responsible for transporting blood throughout the body.
• Components of the circulatory system include blood vessels and a pump.
• Valves ensure one-way blood flow.

Circulatory Systems of Fish and Mammals

• Fish have a two-chambered heart with a single circulation.
• Blood passes through the heart only once per circuit of the body.
• Mammals have a four-chambered heart with a double circulation.
• Blood passes through the heart twice per circuit of the body.

The Mammalian Heart

• The heart is positioned in the chest cavity.
• The right side receives deoxygenated blood from the body and pumps it to the lungs.
• The left side receives oxygenated blood from the lungs and pumps it to the body.
• Blood travels toward the heart in veins and away from the heart in arteries.
• The two sides of the heart are separated by the septum.
• The heart muscle is supplied with blood by coronary arteries.

Monitoring Activity of the Heart

• Heart activity can be monitored using an electrocardiogram (ECG), measuring pulse rate, or listening to valve sounds with a stethoscope.
• Heart rate is measured in beats per minute (bpm).
• To investigate the effects of exercise on heart rate, record the resting pulse rate, and then record the pulse rate every minute for a while after exercise, until the rate returns to resting levels.
• Exercise will increase heart rate, and it may take a while for the rate to return to resting levels.
• Consistency is important for the measurement of breathing rate and pulse rate.

Investigating Effect of Physical Activity on Heart Rate

• Investigating the effects of exercise on the body can be performed in the classroom.
• Breathing rate can be measured by counting breaths per minute, and heart rate by taking a pulse.
• It's important to keep the measurement time consistent, and ensure adequate recovery before testing another activity.
• Physical activity increases both heart rate and breathing rate.
• Heart rate will remain elevated for a time after exercise before returning gradually to resting levels.

Coronary Heart Disease

• The heart is made of cardiac muscle tissue which needs its own blood supply.
• The coronary arteries deliver oxygen and nutrients to the cardiac muscle, and remove waste products.
• If coronary arteries become blocked by fatty deposits (plaques, mostly from cholesterol), blood flow can be restricted, causing health issues.

Identifying Structures in the Heart

• Ventricles have thicker walls than atria because they pump blood at higher pressure.
• The left ventricle has thicker walls than the right ventricle since it pumps blood throughout the body.
• The right ventricle pumps blood to the lungs.
• The septum separates the two sides of the heart and prevents mixing of oxygenated and deoxygenated blood.

The Function of Valves

• The function of all heart valves is to prevent blood flowing backwards.
• There are two sets of valves in the heart: atrioventricular and semilunar valves.
• Atrioventricular valves are located between the atria and ventricles (tricuspid on the right and bicuspid on the left).
• Semilunar valves are located at the exit of the ventricles (pulmonary and aortic valves).

Functioning of the Heart

• Deoxygenated blood from the body flows to the right atrium via the vena cava.
• Blood is pushed through the tricuspid valve to the right ventricle, where it is pumped to the lungs through the pulmonary artery.
• Oxygenated blood returns to the heart via the pulmonary vein, entering the left atrium.
• The bicuspid valve allows blood into the left ventricle.
• From the left ventricle, blood is pumped through the aorta and circulated throughout the body.

Explaining the Effect of Physical Activity on Heart Rate

• Muscles need more oxygen during exercise, and heart rate increases to meet this demand.
• This rate maintains the increase to ensure the removal of extra waste products during, and after exercise.
• Following exercise, the heart continues to beat faster for a while to ensure enough oxygen is delivered to muscle cells to dispose of extra lactic acid.

Blood Vessels

• The blood vessels are a system of closed tubes which carry blood.
• Types of blood vessels include arteries, veins, and capillaries.
• Arteries carry blood away from the heart at high pressure with thick walls and small lumens.
• Veins carry blood back to the heart at low pressure, with thinner walls and wider lumens.
• Valves prevent backward blood flow in veins.
• Capillaries have thin walls, allowing gas exchange in the tissues with the blood.

Blood Vessels & the Liver

• The hepatic artery carries oxygenated blood to the liver.
• The hepatic vein carries deoxygenated blood from the liver to the heart.
• The hepatic portal vein carries deoxygenated blood, from the gut to the liver.

Components of Blood

• Blood is composed of red blood cells (55%), white blood cells, platelets, and plasma (45%).

Components of Blood: Function

• Plasma transports nutrients, waste products, and other substances throughout the body.
• Red blood cells carry oxygen.
• White blood cells defend the body against infection.
• Platelets are involved in blood clotting.

Blood Clotting

• Platelets are fragments of cells that are involved in blood clotting.
• Blood clotting prevents excessive blood loss from wounds, and scabs form to seal the wound.

White Blood Cells

• White blood cells are part of the immune system, defending the body against infection.
• Phagocytes engulf and destroy pathogens (bacteria).
• Lymphocytes produce antibodies and antitoxins to destroy pathogens.

Conversion of Fibrinogen

• Platelets release chemicals, triggering a cascade of processes that turn fibrinogen into fibrin
• Fibrin forms a mesh, trapping red blood cells to form a blood clot.
• The blood clot dries and forms a scab, protecting and sealing the wound.