Cardiovascular System- ALL NOTES Flashcards
What are the 3 phases of the Cardiac Cycle (Haemodynamic)?
1) Ventricular filling
2) Ventricular systole
3) Early diastole
What does Haemodynamic mean?
-This is the Cardiac Cycle, how the blood flows through the body of which takes place through 3 phases.
What does Systole mean?
-Heart Contraction
What does Diastole mean?
-Heart Relaxation
Diagram of the heart?
Valves graph diagram?
What phase of Cardiac cycle is the sound S1 (LUBb)?
-Isvolumetric contraction, caused by the closure of AV vavles
What phase of Cardiac cycle is the sound S2 (DUBb)?
-Isvolumetric relaxation, cause by the closure of SL vavles
What phase of Cardiac cycle is the sound S3?
-Early ventricular filling, caused by tensing of the chordae tendinease and the atrioventricular ring.
- Adults: Ventricular systolic failure, normal in children
What phase of Cardiac cycle is the sound S4?
-Atrial contraction, caused by vibration of the ventricular wall, stiff ventricle, hypertrophy or ischemic ventricle
Electrical system within the heart, what is it?
–Right artrium, there is a SA node, which involuntary stimulates heartbeat. It is a muscle which contracts and generates electrical signals and sends a pulse throughout the body
- AV node of the left side of the heart
- These signals inter nodal tracts
Electrical system within the heart, what is it?
–Right artrium, there is a SA node, which involuntary stimulates heartbeat. It is a muscle which contracts and generates electrical signals and sends a pulse throughout the body
- AV node of the left side of the heart
- These signals inter nodal tracts
Heart Electrical flow diagram?
What is the Bundle Of His?
-It is an elongated segment connecting the AV node and the left and right bundle branches of the septal crest.
-It carries electrical impulses through the centre of the heart.
What happens if the Bundle Of His fibres are blocked?
-You will have problems with your heartbeat
What are the purkinje fibres?
-Fibres of which carry the electrical impulse to the ventricles.
What is the atrioventricular node?
-The atrioventricular node sends an electrical signal to the bundle of his. The electrical signal moves to the purkinje fibres
What are the 4 key properties of the Cardiac Muscle?
-Auto-rhythically
-Excitability
-Conductivity
-Contractility
What does heart Auto-rhythically mean?
-Ability to initiate heartbeat, consistent and continuous at regular pace without any external stimuli
What does the heart Excitability mean?
- Ability to respond to stimuli of adequate strength and duration (threshold or more)
- Ability to generate and process action potential
What does heart Conductivity mean?
-Ability to conduct and transmit impulse through the cardiac tissue
What does heart Contractility mean?
-Ability to contract in response to stimulation (mechanical)
What are the Excitation- Contraction Coupling in Contractile Myocytes steps?
1) AP from adjacent cell excites myocytes and trigger membrane depolarisation in T-tubules
2) Calcium enter the cells via voltage gated channel opens and calcium enters the cells
3) Calcium binds to Ryanodine receptor (RYR) and induce Calcium release from SR
4) Calcium binds to troponin and triggers acting-myosin complex and contraction
5) Calcium unbind from troponin and pumped back into SR
6) Calcium unbinding cause relaxation and excess Ca2+ exchanged with Na+
7) Na+ gradient is maintained by sodium-potassium-ATPase pump
Excitation- Contraction Coupling in Contractile Myocytes steps diagram?