Cardiac Physiology Flashcards
Blood enclosed in specialised vessels is what type of Circulatory system?
Closed
Carries oxygenated blood from heart throughout the body. Arterial or venous circulation
Arterial circulation
Returns de-oxygenated Blood back to the heart
venous circulation
Characteristics of vertebrate cardiovascular system
Multi-chambered heart with complex valves
Blood transported in vessels
Specialist circulatory system in order to carry both oxygenated and deoxygenated blood
Pulmonary circulation function
Responsible for oxygenated Blood that we need to use
Pulmonary circulation is described as an inversed system. Explain
Inversion means artery carries deoxygenated blood and vein carries oxygenated Blood back to the heart
Innovation define:
Process of supplying nerves to an organ or part of the body
Refers to nerve impulses, growth of nerves and control of heart via the nervous system
Stages of mammalian cardiac development
Heart tube formation around week3
Two stages of developmental process:
- Pre-innervation
- Post-innervation
Vena cava function
Responsible for returning Blood to the heart
Inferior vena cava function:
Returns blood from lower body
Superior vena cava function:
Returns Blood from the brain
Atrioventricular ( tricuspid / mitral) valve function:
Responsible for stopping blood returning back into the atrium upon ventricular contraction so no regurgitation of the blood going back into the atrium
Semilunar values function
Stop any black flow going into the ventricle; allows closed pressurised system of Blood travelling around the body
Number of key tendons found within each of the ventricles: function
Protect the values and facilitate the expulsion of Blood from the heart
Chambers of the heart
Atria
Ventricles
Intraventricular septum
AVN
Semilunar valves
Atria function
Receive blood from body (vena cava) or lungs (pulmonary vein)
Ventricles function (RIGHT)
Deliver blood to lungs
Ventricles function (LEFT)
Deliver Blood to rest of the body
Intraventricular septum function
Dividing wall between the ventricles
Contractile cells of the heart called?
Cardiomyocytes
Cells of the heart include:
Cardiomyocytes - contractile cells
Fibroblasts, endothelial cues etc - used to maintain integrity (ECM) and transfer of nutrients from coronary arteries
What is responsible for laying down extracellular matrix such as collagens and other fibrous proteins?
Fibroblasts
What happens to fibroblasts when disease comes?
They become hyperactivated which can lead to inefficient contractile properties
Role of endothelial cells in heart
Transfer nutrients from a coronary circulation, so that cardiomyocytes can use them
Levels of the heart wall from pericardium to heart interor ( endocardium)
Pericardium -> pericardial space -> epicardium -> myocardium -> endocardium
Pericardial space surrounded by sac is?
Pericardium
Epicardium function:
Lots of coronary vessels
Responsible for providing the heart with Blood
Function of fat cells in heart wall
For rapid conversion to energy
Location of cardiomyocytes
Myocardium
Endocardium layer: inside of the heart. Subdivides into:
Endothelial layer:
Subendocardial layer
Subendothelial layer
Endothelium
Coronary arteries function:
Supply Blood a throughout the myocardium
What supplies the left side of the heart with blood, including LAD and circumflex systems
Left coronary arteries
When does myocardial perfusion occur?
In diastole (cardiac relaxation)
Right corny arteries function
Supply the right side of the heart with blood, including the areas controlling cardiac rhythm (SAN and AVN nodes)
Lad = left ascending artery: also known as?
Widowmaker
In coronary artery disease, if LAD blocked, what effect does this have?
Means that not enough oxygen and nutrients get to left side of heart → heart can’t contract property → heart attack
Define cardiac output CO
Volume of blood expelled from LV at each beat
Define ejection fraction EF
% Blood expelled from (left) ventricle at each beat
Normal EF value =
60%
Why is EF 60%?
Because you can’t have complete closure of the ventricles
Will be difficult to open up again
How is EF calculated?
Difference between diastolic and systolic volume
Initiating region for electrical impulse =
SAN
Delay node to enable ventricular filling?
AVN node
Bundle branches: function
Electrical conductance pathways through left and right myocardium, include bundle of HIS
Specialised cardiac myocyte-like cells that are responsible for translating electrical impulse into contractile force?
Purkinje fibres
Delay node is?
AV node
P wave in Cardiac cycle shows?
Atrial depolarisation
QRS complex in Cardiac cycle shows?
Ventricular depolarisation
T wave in Cardiac cycle shows?
Ventricular repolarisation
Volume of blood pumped by one ventricle per minute?
Cardiac output
CO equation
CO = Heart rate X stroke volume
ml/min (Beats/min). (ml/beat)
Effects of exercise on CO
Increased venous return → increased stroke volume → increased cardiac output
Preload is greater → cardiac muscle contracts with greater force
