Heart Flashcards
Why is the left ventricle wall thicker?
higher pressure blood to reach all areas of body
What is the function of the coronary arteries and veins?
supply heart muscles with oxygenated blood and remove waste
what is the function of the papillary muscles?
preventing blood flow by restricting movement of atrioventricular valves beyond the closed position
why is mixing of blood bad?
maximum amount of oxygenated blood to rest of body
transport of fully oxygenated blood through systemic circulation
How is blood flow controlled to be unidirectional
AV valves close -> prevents V to A back flow
SL valves close -> prevents arterial to ventricular back flow
What is the coordination of contraction?
SAN depolarises -> wave of excitation through atria causing contraction
Gathers at AVN to allow full contraction of atria (push all blood to ventricles)
Wave travels down bundle of his and up through purkinje fibres
wave of excitation spread through ventricle walls causing contraction from base upwards
Compare the functions of the sympathetic and parasympathetic nervous system?
sympathetic: accelerator nerve
parasympathetic: vagus nerve
Explain the effect of increase carbon dioxide on heart rate
chemoreceptors in carotid arteries detect decrease in pH
sned impulse via sensory neurone to cardiac control centre in medulla oblongata
stimulates more action potentials along accelerator nerve
SAN increases rate of contractions, increasing heart rate
pumping more blood to lungs for removal of carbon dioxide
What are some examples of cardiovascular disease?
coronary heart disease (angina, heart attacks, heart failure)
strokes
peripheral arterial disease
how does atherosclerosis result in a heart attack?
damage to endothelium (high bp, chemicals, high salt)
LDLs deposited in wall
Phagocytes engulf LDLs
forms foam cells, remain in walls
Fibrous collagen fibres and smooth muscle build up to ‘contain’ damage
Plaque builds up over time
causes narrowing -> if clot forms then blockage
What are LDLs and HDLs?
LDL: more fat, specifically cholesterol
HDL: more protein
Why are fats transported as LDL and HDL?
fats are hydrophobic -> stick together
What are the factors that increase the risk of cardiovascular disease?
smoking
diet - salt, cholesterol/saturated fats
high blood pressure
exercise
genetic tendency
age
gender
