Transport Systems in Animals - Life Sciences Grade 11

Vocabulary flashcards covering the human circulatory system, heart structure, cardiac cycle, blood vessels, cardiovascular disorders, and the lymphatic system based on Grade 11 Life Sciences notes.

Pulmonary circulation

The circuit where blood is pumped from the heart to the lungs to remove $CO_2$ and add oxygen before returning to the heart.

Systemic circulation

The circuit where blood is pumped from the heart to all the body systems and back to the heart again.

Cusps

Tiny flaps of tissue making up valves that flatten against the walls during forward flow and close to block reverse flow.

Pericardium

A double layer of tough, inelastic membrane surrounding the heart that secretes a thin layer of fluid to prevent friction during heartbeats.

Coronary arteries

Arteries located on the outside of the heart that supply the heart muscle with oxygen and nutrients.

Myocardium

The thick layer of cardiac muscle that makes up the wall of the heart.

Atria

The two upper, thin-walled chambers of the heart that collect blood from veins and push it into the ventricles.

Ventricles

The two lower, large, thick-walled muscular chambers of the heart that push blood out to the lungs and the rest of the body.

Septum

The muscular wall separating the left and right sides of the heart to prevent the mixing of oxygenated and deoxygenated blood.

Superior and inferior vena cava

Major veins that bring deoxygenated blood into the right atrium from the upper body and lower body, respectively.

Pulmonary artery

The blood vessel that transports deoxygenated blood from the right ventricle to the lungs.

Pulmonary veins

The four veins that bring oxygenated blood from the lungs into the left atrium.

Aorta

The main artery that transports oxygenated blood from the left ventricle to the rest of the body.

Tricuspid valve

An atrio-ventricular valve with three flaps located between the right atrium and right ventricle that prevents backflow into the atrium.

Bicuspid valve

An atrio-ventricular valve with two flaps located between the left atrium and left ventricle that prevents backflow into the atrium.

Semi-lunar valves

Valves located at the base of the pulmonary artery and the aorta that allow blood to enter the arteries and prevent backflow into the ventricles.

Tendinous chords

Tendons attached to each flap of the AV valves that anchor the flaps and prevent them from being pushed back too far.

Systole

The contraction phase of the cardiac muscle.

Diastole

The relaxation phase of the cardiac muscle.

General Diastole

A $0.4$\,second phase of the cardiac cycle where both atria and ventricles relax, allowing blood to flow into the atria.

Atrial Systole

A $0.1$\,second phase of the cardiac cycle where both atria contract simultaneously to push blood into the ventricles.

Ventricular Systole

A $0.3$\,second phase of the cardiac cycle where the walls of the ventricles contract, pumping blood into the pulmonary artery and aorta.

Sinoatrial (SA) node

The natural pacemaker located in the wall of the right atrium that generates electrical impulses to initiate heart contraction.

Automatism

The inherent property of cardiac muscle to contract and relax automatically without external nervous stimulus.

Medulla oblongata

The region of the brain containing the cardio-vascular centre that regulates heart rate via the autonomic nervous system.

Accelerator nerve

A sympathetic nerve that releases neurotransmitters at the SA node to increase heart rate.

Vagus nerve

A parasympathetic nerve that releases neurotransmitters at the SA node to decrease heart rate.

Arteries

Macroscopic, muscular blood vessels with small lumens that carry blood away from the heart under high pressure.

Veins

Blood vessels with thin muscular layers, large lumens, and semi-lunar valves that carry blood back toward the heart under low pressure.

Capillaries

Microscopic blood vessels consisting of a single layer of endothelium that allow exchange of nutrients, gases, and wastes with tissue fluid.

Hypertension

A condition characterized by abnormally high blood pressure, often referred to as 'the silent killer'.

Hypotension

A condition characterized by low blood pressure that can cause dizziness, fainting, or severe organ damage if prolonged.

Stroke

A medical condition caused by a blocked artery in the brain, depriving brain tissue of oxygen.

Tissue fluid

Blood plasma (minus plasma proteins) that filters through capillary walls into the spaces surrounding tissue cells.

Oedema

Swelling of body tissues caused by an accumulation of excess tissue fluid when lymphatic vessels are blocked.

Lymph nodes

Structures situated along lymphatic vessels that produce lymphocytes and filter out waste products, foreign matter, and bacteria.