Flashcards in Peak Performance Deck (27):
What's aerobic capacity?
Ability to take in, transport and use oxygen
Describe heart rate
Everyone has a slightly different resting heart rate caused by many factors
Large heart- lower due to expelling more blood per beat
Ability to contract without external nervous stimulation
What is stroke volume?
Volume of blood pumped out of the left ventricle each time it contracts
What is the equation for cardiac output?
Stroke volume x heart rate
Describe how the heart beats
Depolarisation at the SAN generating an impulse spreading across right to left atria causing contraction
Impulses pass to ventricles via AVN following a delay
Impulses go to Purkyne fibres (conduct impulses to apex of ventricles)
Impulses spread up through ventricle walls causing contraction from apex upwards
blood squeezed into arteries
What is the SAN?
Sinoatrial node - small area of specialised muscle fibres locating in wall of right atrium below superior vena cava (Pacemaker)
Why is there a delay in heart beats?
Ensures atria have finished contracting and that the ventricles have filled with blood before contraction
What does the non-conducting layer do?
Prevent waves of electrical activity from being passed directly to the ventricles
What is an ECG?
Measures electrical activity of the heartbeat
Change in polarisation causes a small electrical current to be detected
Whats the P wave?
Depolarisation of the atria
Whats the PR interval
Time taken for impulses to be conducted from SAN arcoss to ventricles through AVN
Whats the QRS complex?
Wave of depolarisation
Whats the T wave
Repolarisation of ventricles
How is an ECG carried out?
Electrodes attached to chest
What is tidal volume?
volume of air inhaled and exhaled in one breath
What is basal metabolic rate?
rate of respiration
What is minute volume?
Volume of air inhaled in one minute
What is vital capacity?
Max amount of air a person can inhale and exhale
Describe slow twitch fibres?
Specialised for slower contraction and long periods of excerise
Red (lots of myoglobin)
Little sarcoplasmic reticulum
Low glycogen content
Describe fast twitch fibres?
Specialised for faster contraction
White (little of myoglobin)
Many sarcoplasmic reticulum
High glycogen content
Which nerves are involved in controlling heart rate?
Sympathetic nerve (Increasese)and parasympathetic nerve (vagus nerve)(decreases)
What are the axis of ECG?
X = time
Y = electrical activity
How is heart rate increased?
Skeletal muscles contract and stretch receptors in muscles are stimulated sending impulses to the CCC increasing heart rate
How does increase heart rate increase cardiac output?
Increases venous return increasing stroke volume
How is cardiac output prevented from rising too far?
Pressure receptors in aorta and carotid atery send impulses back to CCC and send inhibitory impulses to SA node