Circulatory System Flashcards by Alexandra Armstrong

List the 3 functions of the circulatory system

Transportation
Regulation
Protection

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list the 3 basic components of the circulatory system and their roles

Blood - transport medium
Heart - pumps blood
Blood vessels - network that distributes blood

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List the constituents of plasma

36% globulins
4% fibrinogen
albumins
proteins
electrolytes
nutrients + waste

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List the 3 cellular elements

Erythrocytes 95.1%
Leukocytes 0.1%
Thrombocytes 4.8%

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Name the 2 types of leukocytes

Granulocytes 70%

Agranulocytes 30%

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What proteins are found in granulocytes?

Neutrophils 65%
Eosinophils 4%
Basophils 1%

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What proteins are found in agranulocytes?

Lymphocytes 25%

Monocytes 5%

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What are the 2 components of blood?

Cellular elements

Plasma

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How many Oxygens can Haemoglobin carry?

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List 3 characteristics of RBCs

Round, flexible biconcave discs
Lack most organelles
Carry haemoglobin to transport O2 + CO2

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Which granulocyte protein appears most in the blood?

Neutrophils

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Describe the function of neutrophils

Active phagocytes that are the 1st line of defence

Act to slow + localise infection

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Describe the function of basophils

Mediate hypersensitivity reactions + infections

- synthesise, store and release heparin + histamine

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Describe the function of eosinophils

Moderate allergic reactions

Increase in parasitic infections

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List 3 characteristics of thrombocytes

Maintain structure of endothelial lining
Initiate haemostasis
Short life span of 7-10 days

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What double layered membrane surrounds the heart?

Pericardium

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The right sided pump receives oxygenated/deoxygenated blood from the body and pumps it to the heart/lungs for oxygenation.

Deoxygenated

lungs

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The left sided pump receives oxygenated/deoxygenated blood from the lungs and pumps it to the body/heart.

Oxygenated

Body

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Which valve opens the ventricle into the pulmonary artery?

Pulmonic valve

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Which valve opens the ventricle into the aorta?

Aortic valve

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What are the 2 types of blood vessels?

Great cardiac vessels

Coronary vessels

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Name the 5 great cardiac vessels

Superior vena cava
Inferior vena cava
Pulmonary artery
Pulmonary vein
Aorta

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Which vessel sustains the highest systolic pressure?

Aorta

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What is the function of a valve?

Ensure unidirectional flow

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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