3. Cardiovascular system Flashcards
What is systemic circulation
Carries oxygenated blood blood from the heart, TO the body tissues and organs
Carries deoxygenated blood and wastes from the tissues, TO the heart
What is Pulmonary circulation
Carries deoxygenated blood from the heart TO the lungs
Carries oxygenated blood from the lungs, TO the heart
Structure of arteries
-thick muscular walls (made of smooth muscles)
-small lumen
Function of arteries
-carry blood at high pressure
-rapid blood flow
-carry blood away from the heart
(most carry OXYGENATED blood expect for the pulmonary artery)
Structure of arterioles
-branch off the arteries (small lumen)
-further from the heart
Function of arterioles
direct oxygenated blood from major artery into the capillary beds
Structure of capillaries
single layer of muscle smooth muscle cells
Function of capillaries
diffusion of nutrients and wastes from blood into tissue and vice versa
Structure of venules
capillaries converge into venues which converge into veins
Function of venules
direct oxygenated blood from a capillary into a vein
Structure of veins
-thin,floppy walled
-large lumen
-one way valves
Function of veins
-carry deoxygenated blood back to heart under low-pressure
-slow, even blood flow
-blood travels in one direction back to the heart
What is the pericardium + structure
outermost layer.
-A fibrous sac that encapsulates the heart
What is the myocardium + structure
middle layer.
-composed of cardiac muscle, involuntary muscle to transmits electrical stimuli
What is the endocardium
inner most layer.
-lines chambers and valves of the heart
Function of the aorta
transports oxygenated blood from left atrium to body tissues
Function of superior vena cava
transports deoxygenated blood from structures above the diaphragm to the right atrium
Function of inferior vena cava
transports deoxygenated blood from structures below the diaphragm to the right ventricle
Function of pulmonary artery
transports deoxygenated blood from the right ventricle to the lungs
Function of Pulmonary vein
transports oxygenated blood from the lungs to the left atrium
Function of right atrium
collects deoxygenated blood via the vena cavas (from the body) and transports it to the right ventricle
Function of right ventricle
collects deoxygenated blood from the right atrium and pumps it to the lungs via the pulmonary vein (through the pulmonary valve)
Function of left atrium
collects oxygenated blood from the pulmonary vein and transports it to the left ventricle
Function of left ventricle
collects oxygenated blood from the left atrium and pumps it to the body via the aorta (through the aortic valve)
What is the septum
muscular wall between the left and right side of the heart
Function of the septum
separates oxygenated and deoxygenated blood
Where is the bicuspid valve
left side
Function of bicuspid valve
prevents regurgitation of blood from left ventricle into left atrium
Where is the tricuspid valve
right side
Function of tricuspid valve
prevents regurgitation of blood from right ventricle into right atrium
What are semilunar valves
aortic and pulmonary valves
What are atrioventricular valves
bicuspid and tricuspid valve
What is the chordae tendinae
thin strong fibrous chords that connect leaflets of bicuspid and tricuspid valve to the papillary muscle
Function of chordae tedinae
regulate opening/ closing valves
Function of bicuspid valve
prevent back flow of blood from left ventricle to left atrium
Function of tricuspid valve
prevent back flow of blood from right ventricle to right atrium
Function of coronary arteries
supply blood and nutrients to the heart
Describe a myocardial infarction
-reduced blood flow in coronary arteries
-Atherosclerosis
-Occlusion (embolus/ thrombus)
Order of structures in cardiac conduction system
SA node, Av node, bundle of HIS, bundle branches, Purkinje fibres
Function of SA node
spontaneously generate electrical impulses (depolarisation)
-triggers atrial contraction
What is the SA node
collection of specialised pacemaker cells
Where is the SA node
upper wall of right atrium/junction of where superior vena can enters
What is the AV node
collection of specialised pacemaker cells
Where is the AV node
inferior right atria
interatrial septum
Function of AV node
conducts electrical impulses from atria and ventricles, controls heart rate
What is the bundle of HIS
specialised conductive cells
Where are the bundle of HIS
an elongated segment connecting AV node and left/right bundle branches of the septum
Function of bundle of HIS
carry electrical signals from AV node to bundle branches
What are the Purkinje fibres
specialised conductive cells
Where are purkinje fibres
myocardium of ventricular walls
Function of purkinje fibres
ventricular contraction
Identify Steps in cardiac cycle
atrial diastole
atrial systole
ventricular systole
ventricular diastole
What is atrial diastole
-all heart muscles in relaxation
-all heart valves are CLOSED
-blood returning to atria
What is atrial systole
-Atria in contraction
-ONLY AV valves open
-blood to ventricles
What is ventricular systole
-Ventricles in contraction
-ONLY semilunar valves are open
-blood passing to arteries
What is ventricular diastole
-all heart muscles in relaxation
-all heart valves are closed
-blood returning to atria
How to measure pulse (tool)
pulse oximeter or stethoscope
What is blood pressure
force of pressure that blood exerts on artery walls during contraction and relaxation
WNL of blood pressure
120/80
What is systolic pressure
When left ventricle contracts it pumps blood into the aorta (120)
What is diastolic pressure
heart is at rest following ejection of blood (80)
How to measure BP (tool)
sphygmomanometer
Where are baroreceptors
aorta and carotid arteries
Steps in Baroreceptor reflex
(stimulus) increase or decrease in BP –> baroreceptors stimulated or inhibited –> message sent to vasomotor and cardioregulatory centres (in brain) –> triggers vasodilation (increased BP) or vasoconstriction (decreased BP) and changes in Q,HR and SV
Outline the functions of the blood
Transport nutrients , oxygen
Maintain body temperature by vasodilation and vasoconstriction
Control pH
Remove toxins from the body
Regulation of fluids / electrolytes through blood plasma
Protection by WBC’s in the immune system
Prevent excessive bleeding by clotting
Identify components of blood
Plasma, erythrocytes, leukocytes, platelets
Whats Buffy coat
platelets and leukocytes (most potent regulating pH)
Structure of erythrocytes
biconcave shape and no nucleus
Function of erythrocytes
carry oxygen and transport it to tissues around the body
Purpose of biconcave shape
increase SA:V, increase rate of diffusion of O2 in and out of cell
increases flexibility and hence oxygen can fit through small capillaries (be delivered very close to the cell)
Purpose of no nucleus
increased space for haemoglobin and hence more oxygen can be carried
Describe blood clot formation
-Vasoconstriction- (blood vessels spasm) to decrease blood flow/loss
-Platelet plug - platelets become activated and sticky, join together
-Coagulation- fibrinogen converted to fibrin (fibrin meshwork forms) and blood goes from liquid to gel (blood clot)
mitral=
bicuspid
