Pe

Section 1.1

Myogenic

Myogenic

The capicity of the heart to generate its own impulse

Blood pressure

The force excerted by the blood aganints the blood vessel wall

Sinoatrial node

A small mass of cardiac muscle found in the wall of the right atrium that generates the heart rate

Atrioventricular node

This node relays the impulse between the upper and lower sections of the heart

Systole

When the heart contracts

Bubdle of his

A collection of heart muscle cells that transmits electrical impulses from AVN to the ventricles

Purkinji fibres

Muscle fibres that conduct inpulses in the walls of ventricles

Sympathetic nervous system

A part of the autonic nervous system that increases heart rate

Parasympathetic nervous systems

Part of the autonic nervous system which decreases heart rate

Medulla oblongata

The most important part of the brain as it regulates processes that keeps us alive such as breathing and heart rate

Chemoreceptors

Tiny structures in the cartoid arteries and aortic arch that detect changes in blood acidity caused by an increase or decrease in carbon dioxide.

What happens to chemoreceptors during excersize

Chemoreceptors detect an increase in CO2 and send a message to the medulla to speed up heart rate

What is a barorecptor

Special sensors in tissues in the aortic arch,cartoid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decrease heart rate

What happens to baro receptors during exercise

Detect an increase in blood pressure and decrease heart rate

What is a propioreceptor

Sensory nerve endings in the muscles, tendons and joint that detect changes in muscle movement

What happens to propioreceptors during excersize

Detect increase in muscle movement and increase hesrt rate

What is adrenaline

A stress hormone that is released by the sympathetic nervous system and cardiac nerve during exercise which causes an increase in heart rate

What is strike volume

The volume of blood pumped out the heart per beat

Diastole

When the heart relaxes to fill with blood

Ejection fraction

The percentage of blood being pumped out by the left ventricle per beat

Starlings law

Increased venous return means greater diastolic filling of the heart resulting in the carduac muscle being streched and so theres mor force of contraction and therfore increased ejection fraction

Give the fraction for ejection fraction

Stroke volume / end diastolic volume ( volume of blood in ventricles at rest

What is heart rate

The number of times the heart beats per minute

Cardiac output

Volume of blood pumped out the heart by the ventricles per minute

Heart rate in relation to exercise

Directly proportional until maximum heart rate is reached

Cardiac hypertrophy

The thickening of muscular walls of the heart so it becomes bigger and stronger

Bradycardia

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

Atherosclerosis

Occurs when ateries harden and narrow as they become clogged up by fatty deposits

Atheroma

A fatty deposit found in the inner lining of an artery

Angina

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

Stroke

A stroke occurs when the blood supply to the brain is cut off

Disability

Physical, sensory or mental impairment which adversely affect preformance

Steady state

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

Effects of cardiovascular drift

Cardiovascular drift occurs after a period of exercise→ heart rate increases→ stroke volume decreases→ becayse fluid lost as sweat→ cardiac output increases due to more energy needed to cool body/sweat

Blood pressure

The force excerted by the blood against the blood vessel wall

Systolic pressure

The pressure in the ateries when the ventricles are contracting

Dyastolic pressure

The pressure in the ateries when ventricles are relaxing

Venous return

The return of blood to the rught side of the heart through the vena cava

Venous return mechanisms

Skeletal muscle pump, repiratory pump, pocket valves, thin layler of smooth muscle in veins to help squeeze blood back to heart, gravity to return blood from upper body and suction pump action from heart

Skeletal muscle pump

When muscles contact and relax they change shape. This means that the muscles press on the nearby veins and cause a pumping effect and squeeze the boood towards the heart

Respiratory pump

When muscles contract and relax during breathing in and out pressure changes occur in the thorrasic (chest) and abdominal (stomach) cavities

Pocket valves

In order for veins to flow in one direction, valves close once the blood has passed through to prevent backflow

Plasma

The fluid part of blood that transports blood cells , 3% of oxygen diffuses into plasma

Haemoglobin

An iron containing pigment flound in red blood cells which combines with 97% of oxygen to form oxyheamoglobin

Myoglobin

Also called the muscle heamoglobin. Its an iron containing muscle pigment in slow twitch muscle fibres which has a higher affinity for oxygen then heamoglonin

Bohr shift

When an increase in carbon dioxide and a decrease in pH results in a reduction of heamoglobin

pH

A measure of acidity the range goes from 1-14