Cardiovascular System SEM2 Flashcards
What does high blood pressure (hypertension) increase the risk of
Stroke
Heart attack
Aortic aneurysm
Kidney disease
Dementia
What is normal blood pressure compared to hypertension
Normal = 120/80 mmHg
Hypertension = 140/90 mmHg
What is systolic blood pressure (SBP)
Left ventricle contracting
What is diastolic blood pressure (DBP)
Left ventricle refilling
How do you calculate cardiac output
Cardiac output = heart rate x stroke volume
What is filling time
The duration of ventricular diastole during which filling occurs
How do you calculate stroke volume
SV= end-diastolic volume (full EDV) - end-systolic volume (empt ESV)
SV= EDV - ESV
What does stroke volume depend on
Contractility - force of contraction
End diastolic volume
What is preload in starlings law of the heart
Preload is the initial stretching of the cardiomyocyte sarcomeres during filling (just before contraction)
What is the consequence of cardiomyocytes stretching more
Incudes greater contraction force - elastic recoil
What are the effects of hypertension on arteries
Induces remodelling and stiffening of arteries
Loss of elasticity
What is Ohm’s law applied to fluid flow
Flow (Q) = to the pressure gradient (delta P) / by resistance (R)
What causes constriction of arteries and arterioles
Ca2+ signalling in vascular smooth muscle cells
What causes dilation of arteries and arterioles
Reduced Ca2+ signalling in vascular smooth muscle cells
What does healthy endothelium regulate
Vessel tone
Movement of fluid into tissue
Leukocyte adhesion
platelet aggregation
What are the three layers the wall of the heart is composed of
Epicardium
Myocardium
Endocardium
What does the epicardium consist of
Simple squamous epithelium called mesothelium
What does the myocardium consist of
Consists of cardiac muscle cells - muscle layer of the heart
What does the endocardium consist of
Layer of endothelial cells in contact with the blood in the chambers of the heart
What valves prevent blood flowing back into the ventricle
Mitral and tricuspid valves (AV valves)
What valves prevent blood flowing back from the ventricle from the aorta and main pulmonary artery
The aortic and pulmonary valves - both are semilunar valves
What is a feature of cardiac muscles and its relation to its contraction
Cardiac muscles are striated - only contract along their long axis
What are properties of cardiac myocytes
Short with single nucleus
Held together by intercalated disks
Cells often branch
Cells held together by adherens junctions
What are muscle fibres surrounded by
Sarcolemma (muscle cell membrane)
What is the triad
The region that consists of a t-tubule with sarcoplasmic reticulum on either side
What is the role of coronary arteries
An extensive network ensuring oxygen supply
What are the names of the 3 layer structure present in all blood vessels (except capillaries)
Intima
Media
Adventitia
How is the pacemaker of the heart formed/initiated by
Cardiac muscle is myogenic -> generates its own action potentials spontaneously at the sino atrial (SA) node
What does skeletal muscle require by being neurogenic
Requires nerve impulse in order to initiate contraction
What are intercalated discs
Specialised junctions that allow for rapid transmission of the action potential
Why are intercalated discs important in the heart
As they allow for the cardiac myocytes in the heart to beat as one
What does the electrocardiogram (ECG) measure
Measure automaticity - HR, rhythmicity, pacemaker
Measure conductivity - pathway, reentry, block
What does the electrocardiogram (ECG) reveal
Reveal hypertrophy
Reveal ischemic damages- location, size and progress
