Circulatory System Flashcards
List the 3 functions of the circulatory system
Transportation
Regulation
Protection
list the 3 basic components of the circulatory system and their roles
Blood - transport medium
Heart - pumps blood
Blood vessels - network that distributes blood
List the constituents of plasma
36% globulins 4% fibrinogen albumins proteins electrolytes nutrients + waste
List the 3 cellular elements
Erythrocytes 95.1%
Leukocytes 0.1%
Thrombocytes 4.8%
Name the 2 types of leukocytes
Granulocytes 70%
Agranulocytes 30%
What proteins are found in granulocytes?
Neutrophils 65%
Eosinophils 4%
Basophils 1%
What proteins are found in agranulocytes?
Lymphocytes 25%
Monocytes 5%
What are the 2 components of blood?
Cellular elements
Plasma
How many Oxygens can Haemoglobin carry?
4
List 3 characteristics of RBCs
Round, flexible biconcave discs
Lack most organelles
Carry haemoglobin to transport O2 + CO2
Which granulocyte protein appears most in the blood?
Neutrophils
Describe the function of neutrophils
Active phagocytes that are the 1st line of defence
Act to slow + localise infection
Describe the function of basophils
- Mediate hypersensitivity reactions + infections
- synthesise, store and release heparin + histamine
Describe the function of eosinophils
Moderate allergic reactions
Increase in parasitic infections
List 3 characteristics of thrombocytes
Maintain structure of endothelial lining
Initiate haemostasis
Short life span of 7-10 days
What double layered membrane surrounds the heart?
Pericardium
The right sided pump receives oxygenated/deoxygenated blood from the body and pumps it to the heart/lungs for oxygenation.
Deoxygenated
lungs
The left sided pump receives oxygenated/deoxygenated blood from the lungs and pumps it to the body/heart.
Oxygenated
Body
Which valve opens the ventricle into the pulmonary artery?
Pulmonic valve
Which valve opens the ventricle into the aorta?
Aortic valve
What are the 2 types of blood vessels?
Great cardiac vessels
Coronary vessels
Name the 5 great cardiac vessels
Superior vena cava Inferior vena cava Pulmonary artery Pulmonary vein Aorta
Which vessel sustains the highest systolic pressure?
Aorta
What is the function of a valve?
Ensure unidirectional flow
Name the 2 AV valves
Tricuspid (right)
Biscupid (left)
Name the 2 Semilunar valves
Pulmonic (right)
Aortic (left)
Name the 3 layers of the heart wall
Endocardium
Myocardium
Epicardium
Name the 2 cardiac cell types
Contractile cells
Electrical cells
Describe the role of contractile cells
Mediate pumping work of the heart
Describe the role of electrical cells
Initiate + conduct action potentials to activate and contract muscle cells
Give examples of electrical cells
Bundle of His
Purkinje fibres
SA node
AV node
List the properties of cardiac cells
Excitability
Refractoriness
Automaticity
Cardiac resting membrane potential that is polarised
Define excitability
Ability to respond to electrical stimulus by eliciting an action potential
Define refractoriness
protecting against premature excitation
Define automaticity
Ability to initiate action potentials spontaneously
Describe the sequence in which electrical cells initiate an action potential
SA node –> Atria –> AV node –> Bundle of His –> Purkinje fibres –> Ventricles
What does an ECG tell us
The summation of overall spread of electrical activity throughout the heart during depolarisation and repolarisation
What does the P wave represent?
Atrial depolarisation
What does the QRS complex represent?
Ventricular depolarisation
What does the T wave represent?
Ventricular repolarisation
Name the 2 types of membrane junctions within an intercalated disc
Desmosomes - anchoring
Gap junctions - communication
Name the 3 tunics in blood vessel walls
Externa
Media
Interna
State the phases and sub phases of diastole and sytsole
Diastole - ventricular filling + relaxation
sub phase - isovolumetric relaxation + filling
Systole - ventricular contraction + emptying
sub phase - isovolumetric contraction + ejection
Name the 2 elastic arteries
Aorta
Pulmonary artery
Name the 2 muscular arteries
Femoral artery
Coronary artery
Which vessel contains the highest % of smooth muscle in the walls?
Arterioles
What 2 processes exchange materials in the capillaries?
Diffusion
Bulk flow
Name the 3 types of capillaries
Continuous
Fenestrated
Discontinuous
What are the determinants of bulk flow?
Capillary blood pressure - OUTWARD
Interstitial fluid colloid osmotic pressure - OUTWARD
Plasma colloid osmotic pressure - INWARD
Interstitial fluid hydrostatic pressure - INWARD
System veins have a high/low resistance due to their small/large radius
Low
Large
Define CO
Volume of blood pumped by the heart per min
Define SV
Volume of blood ejected by the left ventricle per heart beat
What is the equation needed to calculate CO
CO = SV x HR
Describe the determinants of HR
Autonomic tone of the heart
Increasing SNS, increases release of noradrenaline which increases HR
Increasing PNS, binds to muscarinic receptor, decreasing depolarisation, which decreases HR
State the 3 factors affecting SV
Preload
Afterload
Contractility
Increasing preload increases/decreases the stretch of cardiac muscle fibres, which increases/decreases contraction, increasing/decreasing SV
increases
increases
increasing
SV is _____ proportional to preload
directly
Define afterload
Pressure the heart must generate to be able to eject blood into the aorta
SV is ______ proportional to afterload.
Inversely
Increasing afterload _____ SV
decreases
Decreasing afterload increases/decreases SV so the curve shifts up/down and right/left
decreases
up
left
Increasing afterload increases/decreases SV so the curve shifts up/down and right/left
increases
down
right
Define contractility
Heart’s ability to change its force of contraction without changing its resting muscle length
SV is ______ proportional to contractility
directly
Increasing Ca 2+ increaes/decreases actin-myosin cross bridge formation, which increases/decreases contractility, which increases/decreases SV
Increases
increaes
increases
list the determinants of BP
CO
TPR
What determines TPR
Sympathetic tone
Circulating + local hormones
What 2 mechanisms control BP
Short term via baroreceptors
Long term via Kidneys
Describe 3 ways that maintain balance between supply and demand of the coronary circulation
- reduced coronary blood flow during systole
- disproportionate share of CO
- High O2 extraction, low O2 reserve
