Cardiac Conduction System Flashcards
What is the systole?
Contraction phase
What is the diastole?
Relaxation phase
What does the sinotrial node do?
It is the pace maker
- Creates an impulse
- Creates atrial systole
How does the Cardiac Conduction System work?
- Sinotrial Node (SAN) creates an impulse which creates atrial systole
- Impulse reaches Atrioventricular Node (AVN) (0.1-0.2s)
- Impulse sent down bundle of HIS
- Goes to Purkinje Fibres which causes ventricular systole
What does the AVN node do?
Atrioventricular Node (AVN) holds the impulse from thee SAN for 0.1s-0.2s then releases the impulse into the bundle of HIS
What does the bundle of HIS do?
Spreads out the impulse released from the AVN into the Purkinje Fibres
What do the Purkinje Fibres do?
Causes the ventricles to contract (ventricular systole)
What is the mnemonic for the Cardiac Conduction System? SAABPV
Sally Always Aims Balls Past Vicky
- SAN
- Atrial Systole
- AVN
- Bundle of HIS
- Purkinje Fibres
- Ventricular Systole
What is the Sympathetic System?
A part of the autonomic nervous system that speeds up heart rate
What is the Parasympathetic System?
A part of the autonomic nervous system that decreases heart rate
What are Chemoreceptors?
Tiny structures in the carotid arteries and aortic arch that detect changes in blood acidity causes by an increase or decrease in the concentration of carbon dioxide.
Increased concentration of carbon dioxide will stimulate the sympathetic nervous system, causing heart to beat faster.
What are Baroreceptors?
Special sensors in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decrease heart rate.
What are Proprioceptors?
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement.
At start of exercise they detect an increase in muscle movement which sends an impulse through the sympathetic nervous system to the SAN to increase heart rate.
What is Myoglobin?
An iron-containing muscle pigment in slow-twitch muscle fibres which has a higher affinity for oxygen than haemoglobin.
It stores the oxygen in muscle fibres which can be used quickly when exercise begins.
What is Haemoglobin?
An iron-contains pigment found in red blood cells, which combines with oxygen to form oxyhemoglobin.
Red blood cells carry oxygen to the areas needed in the body.