introduction to circulation Flashcards
what are 2 functions of circulation?
- supply oxygen to tissues
- remove waste
where do pathologies in circulation arise from?
- diminished oxygen
- diminished perfusion
what is the single objective of the cardiovascular system?
perfusion (flow through a given tissue)
what leads to hypertension?
vessel damage, heart damage, many pathologies
what leads to hypotension?
syncope (or shock)
what leads to shock?
insufficient perfusion
which side of the heart is responsible for pulmonary circulation?
right side
what side of the heart is responsible for systemic circulation?
left side
what are some functions of cardiovascular circulation?
- carry oxygen, glucose & nutrients to cells
- removes waste: carbon dioxide & heat
- homeostasis of the extracellular fluid
- distribution of hormones
- temperature regulation
- defence against infections
what is the key blood pressure equations?
BP = CO x PR
CO = cardiac output PR = peripheral resistance
what is the function of the aorta?
stretch & recoil, stores energy
what is the function of the arteries?
distribute, volume adjust
what is the function of the arterioles?
regulates caps, resistance, set BP & TPR
what is the function of the capillaries?
exchange (gas, nutrients & fluid)
what is the function of the venules?
collect blood, some exchange
what is the function of the veins?
reservoir for blood (nearly 2/3of blood volume), muscle pump
describe a few distinctive features of the pulmonary circulation
- right ventricle
- thin walled
- crescent X-section
- lungs only
- low pressure
- high flow
- low resistance
describe a few distinctive features of the systemic circulation
- left ventricle
- thick wall
- circular X-section
- multiple organs
- high pressure
- variable flow
- variable resistance
what is systole?
when ventricles contract, blood is ejected
what is diastole?
when ventricles relax, blood can fill the ventricles
what is the apex beat?
at systole the apex of heart moves forward and strikes chest wall
what are valves?
flaps of tissue inside a blood vessel, they guarantee one-way flow of blood
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
how many leaflets do heart valves have?
3 leaflets except mitral (bicuspid) valve
what is the function of the chordae tendinae?
stop valve leaflets from flipping inside out
what are the 13 steps in order of the blood circulation in the heart?
1) superior & inferior vena cava (arrives deoxygenated)
2) right atrium
3) tricuspid valve
4) right ventricle
5) pulmonary valve
6) pulmonary artieries
7) lungs (oxygenated)
8) pulmonary veins
9) left atrium
10) mitral (bicuspid) valve
11) left ventricle
12) aortic valve
13) systemic circulation
which 2 valves are artioventricular?
mitral and tricuspid
which 2 valves are semilunar?
aortic and pulmonary
describe the atrioventricular valves & what their function is
- papillary fibres (prolapse)
- close during systole
- S1: first heart sound (lub)
describe the semilunar valves & what their function is
- moon shaped
- close during diastole
- S2: second heart sound (dub)
which is longer: systole or diastole?
diastole
how does the heart contract?
- heart muscular cell is electrically stimulated by a neighbour & conducting system
- myocyte becomes electrically activated by an action potential
- free intracellular calcium increases
- muscle contracts
- calcium is removed & muscle relaxes
is an extracell or intracell positive?
intracell
what is blood pressure determined by?
circulating blood volume & circulatory capacity
what are the kidneys controlled by?
endocrine system & autonomic nervous system
how do you decrease filtration in the kidney?
constrict afferent artery
how do you increase filtration in the kidney?
dilating afferent artery & constricting efferent artery
what is the 1 input of the kidney?
afferent arteriole
what are the 2 exits in the kidney?
into the Bowman’s capsule or the efferent arteriole
what is the glomerular filtrate rate (GFR) measured in?
ml/min
what happens when glomerular filtrate rate is increased?
fluid lost to urine
what happens when there is increased renal blood flow?
increased glomerular filtrate rate
what is anoxia?
complete deprivation of oxygen supply
what is anaemia?
low haemoglobin
what is ischaemia?
insufficient blood flow to a region
what causes ischaemia?
- clog, constriction or closed blood vessel
- insufficient blood volume
- insufficient pressure generation of the heart
what is angina pectoris?
- a symptom
- chest pain due to over-exertion of (damaged) heart tissue
how do you treat angina pectoris?
nitrate for immediate relief
what is the immediate cause of angina pectoris?
ischaemia or heart tissue due to an obstruction (or spasm) of a coronary artery
what is a myocardial infarction (MI)?
- death of one region in the heart
- sudden crushing chest pain
what causes a myocardial infarction?
occlusion of a coronary artery
what is the treatment for a myocardial infarction?
- immediate reperfusion (PCI)
- morphine, oxygen, nitrates, aspirin
what is heart failure?
- heart pumps out insufficient blood
- results from previous MIs
what are the symptoms of heart failure?
fatigue, dyspnoea, oedema
what is shock?
critically low perfusion
what does shock affect?
cerebral & renal function
what is syncope?
loss of consciousness (fainting)
what causes syncope?
insufficient blood flow to the brain caused by a heart malfunction (shock & arrhythmia)
