introduction to circulation Flashcards
how can pathologies arise from circulation? 2
- diminished oxygen
- diminished perfusion
what is perfusion?
flow through a given tissue
what happens if blood pressure is too low? 3
hypotension
insufficient delivery of blood and oxygen
syncope or shock
what happens if blood pressure is too high? 2
hypertension
vessel/heart damage
what are the two circulations of the heart, their pumps and types of flow?
pulmonary- right heart- series based flow, one direction, no branching
systemic- left heart- parallel circulation, branching paths which are concurrent
what are the functions of circulation? 6
- carry oxygen, glucose and nutrients to cells
- removing waste (CO2 and heat)
- homeostasis of the extracellular fluid (via kidneys)
- distribution of hormones
- temperature regulation
- defence against infections
what is the formula for blood pressure?
BP= cardiac output x peripheral resistance
between which points are sounds heard when taking bp and what do they show?
systole
diastole
artery is opening and closing
what is the function of the aorta? 2
- stretch and recoil
- stores energy
what is the function of the arteries? 2
- distribute
- volume adjust
what is the function of the arterioles? 2
- resistance
- set BP and TPR (total peripheral resistance)
what is the function of the capillaries?
exchange
what is the function of the venules? 2
- collect blood
- some exchange
what is the function of the veins? 2
- reservoir for blood
- muscle pump
how much of the blood volume is in the veins?
64%
describe the right heart? 5
- lungs only
- low pressure
- high flow
- low resistance
- right ventricle= thin walled= crescent cross section
describe the left heart? 4
- multiple organs
- variable flow
- variable resistance
- left ventricle= thick walled= circular cross section
what is systole?
when the ventricles contract and blood is ejected
what is diastole?
when ventricles relax, blood can fill the ventricles
what is an apex beat?
at systole, apex of the heart moves forward and strikes the chest wall
when do valves open?
when pressure is higher on the inflow side
when do valves close?
when the pressure is higher on the outflow side to prevent backflow
how many leaflets do most heart valves have? what is the exception?
3
mitral valve/ bicuspid valve in left heart
what prevents valves flipping inside out?
chordae tendineae help the valves withstand the pressure
name 2 types of AV valves and what they do? 3
- mitral and tricuspid
- papillary fibres
- close during systole
- S1 (first heart sound- lub)
name 2 types of semilunar valves and what they do? 4
- aortic and pulmonary
- moon shaped
- close during diastole
- diastole is longer that systole
- S2 (second heart sound-dub)
what is blood pressure determined by?
-the balance between circulating blood and circulatory capacity
what is blood volume determined by? 2
the kidneys
sodium and water are central to volume setting
why do blockages in your vessels affect bp?
decreases the circulatory capacity for the same amount of blood, increasing the pressure
why is kidney filtration important for bp? 5
- many small molecules go through the filter (water, glucose, ions)
- blood cells and proteins can’t go through
- desirable molecules are reabsorbed
- excess fluid and undesirables are left behind are excreted
- this keeps the blood volume consistent
what is the filter in the kidney called? what is the filtration unit called?
glomerulus (1 million per kidney)
nephron
what is glomerular filtration rate? 3
- fluid entering all bowman’s capsules under the glomerulus
- in ml/min
- increase leads to fluid loss in urine
what is the input to the glomerulus?
the two outputs?
- afferent arteriole
- bowman’s capsule or efferent arteriole
what is hypoxia
anoxia
hypoxaemia
- insufficient oxygen supply to tissues
- no oxygen supply
- insufficient oxygen supply to the whole blood system
what is ischemia?
insufficient blood flow to a region
always leads to hypoxia
what is angina pectoris? 3
treatment? 2
- chest pain due to overexertion of damaged heart tissue
- can occur with or without physical exertion
- immediate cause is ischaemia of heart tissue due to an obstruction
- nitrates for immediate relief
- long term treatments are the same for coronary heart disease
what is myocardial infarction? 4
treatment?
- death of one region in the heart
- sudden crushing pain
- occlusion of coronary artery
- immediate reperfusion (PCI)
-MONA morphine oxygen nitrates aspirin
what is heart failure? 5
- pump failure- insufficient blood
- fatigue
- dyspnoea (difficulty breathing)
- oedema
- results from previous MI
what is shock? 4
- critically low perfusion
- medical emergency
- affects critically ill patients
- affects cerebral and renal function
what is syncope? 4
- loss of consciousness
- fainting due to insufficient blood flow to the brain
- not a seizure
- can be due to heart malfunction
