A Level PE (AQA) - The Cardiovascular System

Cardiovascular System

The body's transport system, which includes the heart and the blood vessels

Septum

The muscular wall, dividing the heart into 2

Atria

The smaller chamber of the heart, which has thinner muscular walls

Ventricles

The larger chamber of the heart, with thicker muscular walls

Vena Cava

Brings deoxygenated blood back to the Right Atrium

Pulmonary Vein

Beings oxygenated blood to the Left Atrium. Only vein to carry oxygenated blood

Pulmonary Artery

Exits the Right Ventricle with deoxygenated blood, to go to the lungs. Only artery to carry deoxygenated blood

Aorta

Exits the Left Ventricle with oxygenated blood, to go to the body

Valves

Regulate blood flow by ensuring that it moves in one direction. They open to allow blood to pass through, and then close to prevent back flow

Tricuspid Valve

Between the Right Atrium and the Right Ventricle

Bicuspid Valve

Between the Left Atrium and the Left Ventricle

Semi-Lunar Valve

Between the Right and Left Ventricle and the Pulmonary Artery and Aorta

Cardiac Conduction System

How a heart beats

Movement of blood

IN through Atria and OUT through Ventricles

Myogenic

The capacity of the heart to generate its own impulses

Systole

When the heart contracts

CCS Order

SAN - Atrial Systole - AVN - Bundle of His - Purkinje Fibres - Ventricular Systole

Neural Control Mechanism

Involves sympathetic and parasympathetic nervous systems

Nervous System

Consists of the CNS and the Peripheral Nervous System that are both controlled by the Cardiac Control Centre

CNS

One part of the Nervous System that consists of the Brain and Spinal Cord

Peripheral Nervous System

One part of the Nervous System that consists of the nerve cells to transmit information to and from the CNS

Cardiac Control Centre

Found in the Medulla Oblongata in the brain and controls the Nervous System. It is stimulated by Chemoreceptors, Baroreceptors and Proprioceptors

Chemoreceptors

Located in the Carotid Arteries and sense chemical changes as they detect and increase in Carbon Dioxide during exercise. It stimluates the Sympathetic Nervous System. An increase in Carbon Dioxide means an increase in Heart Rate

Baroreceptors

Contain nerve endings, that respond to the stretching of the arterial wall, which is caused by the changes in blood pressure. An increase in Blood Pressure means a decrease in Heart Rate

Proprioreceptors

Sensory nerve endings which are located in the muscles, tendons and joints. They provide information about movements and body position. An increase in Muscle Movement means an increase in Heart Rate

Adrenaline

A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise, which causes an increase in heart rate. The release of Adrenaline acts as Hormonal Control

Stroke Volume

The volume of blood pumped out by the heart ventricles in each contraction. Depends on Venous Return and the Elasticity of Cardiac Fibres

Venous Return

Volume of blood returning to the right side of the heart via the vena cava. An increase in Venous Return means a increase in Stroke Volume

Elasticity of Cardiac Fibres

How much the cardiac tissue can stretch during the diastole phase

Heart Rate

The number of times the heart beats per minute

Cardiac Output

The volume of blood pumped out by the heart ventricles per minute

Diastole phase

The relaxation of the heart, allowing it to fill up with blood

Ejection fraction

The percentage of blood pumped out of the Left Ventricle per beat

Starlings Law

Increased Venous Return means that there is a greater diastolic filling of the heart, meaning that the cardiac muscle is stretched so that there is a larger force of contration and therefore an increased ejection fraction

Cardiac Hypertrophy

The thickening of the muscular wall of the heart so that it becomes bigger and stronger. It can also mean a larger ventricular cavity

Bradycardia

A decrease in resting heart rate to below 60 beats per minute

Maximal exercise

Exercise to (exhaustion) maximum intensity. A sharp rise in heart rate due to anarobic work, followed by a rapid decline in heart rate as exercise stops

Sub-maximal exercise

A sharp rise in heart rate due to anaerobic work, followed by a steady state as the athlete is able to meet the oxygen demands. This is then followed by a rapid decline

Atherosclerosis

Occurs when arteries harden and narrow as they become clogged up by fatty deposits. This can be caused by high blood pressure, high levels of cholesterol, lack of exercise and smoking

Atheroma

A fatty deposit found in the inter lining of an artery

Angina

Chest pain that occurs when the blood supply through the coronary arteries to the muscles of the heart is restricted

Blood pressure

Force exerted by the blood against the blood vessel wall

High blood pressure

Leads to extra strain on the arteries and heart, which can increase the risk of a heart attack, heart failure, kidney disease, stroke or dementia

Low Density Lipoproteins

The 'bad' cholesterol that leads to an increased risk of heart disease. Transport cholesterol in the blood to tissues.

High Density Lipoproteins

The 'good' cholesterol that transports excess cholesterol in the blood back to the liver where it is then broken down. It lowers the risk of heart disease

Stroke

Occurs when the blood supply to the brain is cut off

Ischaemic stroke

Most common form of a stroke and occurs when a blood clot stops the blood supply to the brain

Haemorrhagic stroke

A type of stroke that occurs when a weakened blood vessel supplying to brain bursts

Cardiovascular drift

A progressive decrease in stroke volume and arterial blood pressure, which means a progressive rise in heart rate

Steady state

Where the athlete is able to meet the oxygen demand with the oxygen supply

Pulmonary circulation

Deoxygenated blood from the heart to lungs AND oxygenated blood back to the heart

Systematic circulation

Oxygenated blood to the body from the heart AND then the return of deoxygenated blood from the body to the heart

The Vascular System

Made up of blood vessels that carry blood through the body, delivering oxygen and nutrients to the blood vessels and taking away waste products

Arteries

Blood vessel of systematic circulation. The largest blood vessels that spread away from the heart and reduce in size to become arterioles and capillaries

Capillaries

A reduced artery in systematic circulation. They flow into venues and then veins before entering the Right Atrium from either the inferior Vena Cava from the lower body OR the superior Vena Cava from the upper body

Smooth muscle

Involuntary muscle found in the blood vessel walls

Vasodilate

Widening of arteriole blood vessels

Vasoconstrict

Narrowing of arteriole blood vessel walls

Venodilate

Widening of venous blood vessels

Venoconstrict

Narrowing of venous blood vessel walls

Systolic Pressure

The pressure in the arteries when the ventricles are contracting

Diastolic Pressure

The pressure in the arteries when the ventricles are relaxing

Pocket Valves

Venous Return Mechanism - Located in the veins, preventing back flow of blood, which in turn helps the blood to go to the heart. Once the blood passes through it, it closes

Skeletal Muscle Pump

Venous Return Mechanism - Major mechanism promoting venous return by the contracting muscles squeezing the veins as they change shape when they contract and relax. The squeezing of the veins cause a pumping effect

Respiratory Pump

Muscles contract and relax during breathing in and out. Pressure changes occur in the thoracic and abdominal cavities. The changes in the pressure compress the nearby veins and assist blood returning to the heart

Venous Pressure (Pv)

Pressure in veins bringing blood back to the heart

Right Atrial Pressure (Pra)

Pressure in the Right Atrium

Venous Vascular Resistance (Rv)

Amount of resistance in the circulatory system during venous return

Pressure gradient

Venous pressure - Right atrial pressure / Venous vascular resistance

Plasma

The fluid part of blood (mainly water) that surrounds blood cells and transports them

Haemoglobin

An iron-containing pigment found in red blood cells, which combines with oxygen to form oxyhaemoglobin

Myoglobin

Iron containing muscle pigment found in slow twitch muscle fibres where oxygen is stored

Mitochondria

The powerhouse of the cell, where aerobic respiration takes place and energy is produced

Oxyhaemoglobin Dissociation

Release of oxygen from oxyhaemoglobin to the tissues and muscles

pH

A measure of acidity. The range goes from 1 to 14, and anything less than 7 indicates acidity

BOHR shift

When an increase in blood carbon dioxide and a decrease in pH results in a reduction of the affinity of haemoglobin for oxygen

Vascular Shunt Mechanism

The redistribution of cardiac output. Skeletal muscles require more oxygen during exercise, so more blood needs to be redirected to them in order to meet the increased oxygen demand

A-VO2 Difference

Difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles