Paper 1 Cardiovascular System Flashcards
Myogenic
The capacity of the heart to generate its own electrical impulse
Diastole
The relaxation phase of cardiac muscle where the atria and ventricles relax, they expand drawing blood into the atria
Pressure in the atria increases, opening AV valves
Blood passively enters the ventricles
Do valves are closed to prevent blood from leaving the heart
Atrial Systole
The contraction phase of cardiac muscle when the atria contract, forcing remaining blood into the ventricles
Stroke volume
The volume of blood ejected from the left ventricle per beat
Cardiac output
Volume of blood ejected from left ventricle per minute
Venous return
The volume of blood returning to the right atria through the veins
Cardiac control centre
A control centre in the medulla oblongata responsible for HR regulation
Sympathetic nervous system
Part of the automatic nervous system responsible for increasing HR, specifically during exercise.
Parasympathetic nervous system
Part of the automatic nervous system responsible for decreasing HR, specifically during recovery
Vascular shunt
The redistribution of cardiac output
Sternocleidomastoid muscle
Long muscle at the side of neck
Ventricular systole
- The ventricles contract, increasing the pressure closing the AV valves to prevent backflow into the atria
- SL valves are forced open as blood is ejected from the ventricles into the aorta and pulmonary artery
Conduction system order
- Sino- atrial node
- Atrial ventricular node
- Bundle of his
- Purkinje fibres
Bradycardia
A resting heart rate below 60 bpm
Very efficient hearts
Protective effect against cardiovascular and coronary heart disease
Three types of heart rate regulation
- Neural control
- Intrinsic control
- Hormonal control
Neural control
- Chemoreceptors located in the muscles, aorta and cartoid arteries inform the CCC of chemical changes in the blood stream, such as increased co2 and lactic acid
- Proprioceptors located in the muscles, tendons and joints inform the CCC of motor activity
- Baroreceptors located in the blood vessel walls inform the CCC of increased blood pressure
Intrinsic control
- Temperature changes will affect the viscosity (thickness) of the blood and speed of nerve impulse transmission
- Venous return changes will affect the stretch in the ventricle walls, force of ventricular contraction and therefore stroke volume
Hormonal control
- Adrenaline and noradrenaline are released from the adrenal glands increasing the force of ventricular contraction (therefore SV) and increasing the speed of electrical activity through the heart (therefore HR)
Vasodilate
Widening of arteries, artérioles and pre capillary sphincters
Vasoconstrict
Narrowing of arteries, artérioles and pre capillary sphincters
Blood pooling
Accumulation of blood in the veins due to gravitational pull and lack of venous return
Artérioles
Blood vessels carrying oxygenated blood from the arteries to the capillary beds, which can vasodilate and vasoconstrict to regulate blood flow
Pre capillary sphincters
Rings of smooth muscles at the junction between arterioles and capillaries, which can dilate it constrict to control blood flow stheough the capillary bed.
How age affects Vo2 max
After the age of 25, vo2 max decreases by 1% per year.
Regular physical activity can help to offset this decline.
How gender affects vo2 max
Women:
- Generally have 15-30% lower vo2 max than men
This takes into account differences in body weight.
With straight like for like comparisons, the difference is even greater
Training status affect on vo2 max
Athletic training can alter a persons vo2 max by as much as 20% depending on their lifestyle and fitness habits
Conduction system - Sino atrial node
Located in the right atrial wall
The SA node generates its own electrical impulses that pass through the muscular walls, forcing them to contract
The SA node is more commonly known as the “pacemaker” as the firing rate will determine heart rate
Conduction system - Atrio-ventricular node
The AV node collects the impulse and delays it for approximately 0.1 seconds to allow the atria to finish contracting.
It then releases the impulse to the Bundle of His
Conduction system - Bundle of His
Located in the septum of the heart
The bundle of His splits the impulse in two, ready to be distributed through each separate ventricle
Conduction system - Bundle Branches
These carry the impulse to the base of each ventricle
Conduction system - Purkyne fibres
These distribute the impulse through the ventricle walls, causing them to contract
Effects of regular training on lifestyle diseases on the cardiovascular system
- Reduced levels of blood lipids (fats) and overall cholesterol and increase the proportion of HDL to LDL cholesterol
- This will slow the development of atherosclerosis
- Increased coronary circulation (blood flow around the heart) as coronary artérioles gain an increased diameter and density
- This will help to reduce the incidence of heart attacks
What is the name of the main vein in the body
Vena Cava
Veno constriction
Narrowing/constriction of veins
Veno dilation
Widening/dilating of veins
