12. Chapter 14- Cardiovascular Physiology Flashcards
What does the circulatory system do?
Provides a concentration gradient from the blood to cells for nutrients and in the opposite direction for waste
What are the primary and secondary roles (3 of them) of the circulatory system?
Primary- distribution of gases and other molecules for nutrition, growth and repair, while simultaneously removing cellular wastes
Secondary- chemical signalling to cells by circulating hormones or neurotransmitters
- dissipation of heat by loving heat from core to surface of body
- mediation of inflammatory and host defense responses against invading microorganisms
How was the circulatory system originally thought to be? (The two systems)
Who proved it wrong?
- Venous blood was made in liver and distributed throughout body
- Arteries contained air from lungs and spirits which flow to heart
Tissues were thought to consume all blood delivered to them and liver constantly made new blood
Dr William Harvey showed that the heart pumped more than entire body weight in blood in an hour and there was no way the liver could do that
What were Dr William Harvey’s 2 big discovery’s on the heart?
- Showed the valves of the heart and veins created a one way flow of blood and that veins carried blood back to the heart not limbs
- Showers blood entering the heart from the right side had to be pumped through the lungs before entering the left side of the heart
What are the three types of transport in the circulatory system?
- Materials entering the body
- Materials moved from cell to cell
- Materials leaving the body
Examples on slide 7 Nov 7
What are the two circuits the heart uses to pump blood?
What are the 4 compartments of the heart?
Pulmonary circuit- leaves right side of heart and enters left side and goes to pulmonary capillaries in lungs
Systemic circuit- leaves left side of heart and enters right side
Right atrium, right ventricle, left atrium, left ventricle
Slide 8 Nov 7 (notice the left and right are relative to how the heart would be placed in us)
What are arteries, veins, vena cava, and capillaries
Arteries- carry blood away from heart
Veins- carry blood back to heart
Capillaries- smallest vessels where transport takes place
Vena cava- there is superior vena cava which brings blood into the right atrium from the head brain and arms and the inferior vena cava which brings blood from the trunk, liver, digestive tract, kidneys, pelvis and legs
Slide 9
Study the heart (slide 10 nov 7) and location of the: Superior vena Cana Right pulmonary arteries Right pulmonary veins Inferior vena cava Aorta Left and right atrium Left and right ventricle Septum Left pulmonary arteries Left pulmonary veins Descending Aorta Know where each takes blood on slide 11 nov 7
Systematic veins->Venae cavae->right atrium->right ventricle->pulmonary trunk (artery)->lungs
Pulmonary veins->veins of lungs->left atrium->left ventricle->aorta->all body except lungs (systemic arteries)
How does blood flow through cardiovascular system?
What is driving pressure?
Flow down pressure gradients (high pressure to low pressure)
Initial region of high pressure in cardiovascular system is created by contraction of heart, blood flows out of high region into low pressure vessels
Driving pressure is the high pressure in ventricles
Graph on slide 12 nov 7
How is pressure gradient found?
ΔP=P1-P2
Needs to be positive pressure gradient for fluid to flow through a tube
Size of the pressure gradient determines the flow
Look at examples on slide 14 nov 7
What opposes flow?
What is flow directly proportional to?
What about inversely proportional to?
Resistance
Friction in the walls of a tube
Flow is directly proportional to the fourth power of the vessel radius
When radius of tube decreases, resistance to flow increases
Flow is inversely proportional to the length of the vessel and viscosity of the liquid
Short length tube will have less resistance and more flow
Slides 16 and 17 nov 7
How long does the heart rest between beats?
In one minute of work how much work will the heart perform?
How many times will the heart contract in a 70 year lifetime?
Rests for milliseconds between beats
In one minute heart performs the same work of lifting a five pound weight up 1 foot
In a 70 year life span the heart will contract >2.2 billion times
What is the pericardium?
What is the Hart mainly composed of?
Double walled sac filled with a thin layer of clear pericardial fluid
Lubricates the external surface of the heart as it beats within the sac
The heart itself is mostly composed of myocardium covered by thin inner and outer layers of epithelium and connective tissues
What is the tricuspid valve and the mitral valve?
What are these valves attached by?
What are semilunar valves? (2 types)
Tricuspid valve- right atrium to right ventricle
Mitral valve- left atrium to left ventricle
The atrium-ventricle valves are attached to papillary muscle in each ventricle by chordae tendineae
Slide 22 nov 7
Semilunar valves are one way valves that exist between the ventricle and outflow artery
Left ventricle to aorta- aortic valve
Right ventricle to pulmonary artery- pulmonary valve
Slide 23 nov 7
Slide 24 nov 7
What is the cardiac conduction system? (Cardiac action potential SA node AV node)
The cardiac action potential originates in a group of cells in the SA node (pacemaker) then spreads through network of autorhythmic cells (these set heart rate)
The AV node and purkinje fibres have slower pacemaker activity over ridden by SA node
SA node->internodal pathways->AV mode->AV bundle (bundle of His)->bundle branches->purkinje fibres
Slide 13 Nov 9
What is atrial conduction and it’s four conduction bundles?
Backmans bundle- conducts action potential from SA pacemaker into left atrium causing contraction
Anterior, middle, and posterior intermodal pathways- conduct the action potential from SA node to AV node, depolarizing right atrial muscle along the way
Slide 15 Nov 9
What is ventricular conduction?
Layer of connective tissue prevents conduction directly from atria to ventricle
- conduction slows through AV node to allow blood from atria to empty in to ventricles, depolarization proceeds through the septum to the apex, then spreads up walls of the ventricles from apex to bad
Slide 16 nov 9
What happens if electrical activity cannot be transferred from the atria to ventricles?
Complete conduction block is caused by damage in conduction pathway
Ex: block at bundle of His results in complete dissociation between the atria and ventricles
Sa node continues to be a pacemaker for atria, but electrical activity does not make it to the ventricles so purkinje fibers take over as pacemakers for ventricles
THIS REQUIRES ARTIFICIAL PACEMAKERS