introduction to circulation

Question 1

how can pathologies arise from circulation? 2

Answer 1

• diminished oxygen

- diminished perfusion

Question 2

what is perfusion?

Answer 2

flow through a given tissue

Question 3

what happens if blood pressure is too low? 3

Answer 3

hypotension
insufficient delivery of blood and oxygen
syncope or shock

Question 4

what happens if blood pressure is too high? 2

Answer 4

hypertension

vessel/heart damage

Question 5

what are the two circulations of the heart, their pumps and types of flow?

Answer 5

pulmonary- right heart- series based flow, one direction, no branching
systemic- left heart- parallel circulation, branching paths which are concurrent

Question 6

what are the functions of circulation? 6

Answer 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

Question 7

what is the formula for blood pressure?

Answer 7

BP= cardiac output x peripheral resistance

Question 8

between which points are sounds heard when taking bp and what do they show?

Answer 8

systole
diastole
artery is opening and closing

Question 9

what is the function of the aorta? 2

Answer 9

• stretch and recoil

- stores energy

Question 10

what is the function of the arteries? 2

Answer 10

• distribute

- volume adjust

Question 11

what is the function of the arterioles? 2

Answer 11

• resistance

- set BP and TPR (total peripheral resistance)

Question 12

what is the function of the capillaries?

Answer 12

exchange

Question 13

what is the function of the venules? 2

Answer 13

• collect blood

- some exchange

Question 14

what is the function of the veins? 2

Answer 14

• reservoir for blood

- muscle pump

Question 15

how much of the blood volume is in the veins?

Answer 15

64%

Question 16

describe the right heart? 5

Answer 16

• lungs only
• low pressure
• high flow
• low resistance
• right ventricle= thin walled= crescent cross section

Question 17

describe the left heart? 4

Answer 17

• multiple organs
• variable flow
• variable resistance
• left ventricle= thick walled= circular cross section

Question 18

what is systole?

Answer 18

when the ventricles contract and blood is ejected

Question 19

what is diastole?

Answer 19

when ventricles relax, blood can fill the ventricles

Question 20

what is an apex beat?

Answer 20

at systole, apex of the heart moves forward and strikes the chest wall

Question 21

when do valves open?

Answer 21

when pressure is higher on the inflow side

Question 22

when do valves close?

Answer 22

when the pressure is higher on the outflow side to prevent backflow

Question 23

how many leaflets do most heart valves have? what is the exception?

Answer 23

3

mitral valve/ bicuspid valve in left heart

Question 24

what prevents valves flipping inside out?

Answer 24

chordae tendineae help the valves withstand the pressure

Question 25

name 2 types of AV valves and what they do? 3

Answer 25

• mitral and tricuspid
• papillary fibres
• close during systole
• S1 (first heart sound- lub)

Question 26

name 2 types of semilunar valves and what they do? 4

Answer 26

• aortic and pulmonary
• moon shaped
• close during diastole
• diastole is longer that systole
• S2 (second heart sound-dub)

Question 27

what is blood pressure determined by?

Answer 27

-the balance between circulating blood and circulatory capacity

Question 28

what is blood volume determined by? 2

Answer 28

the kidneys

sodium and water are central to volume setting

Question 29

why do blockages in your vessels affect bp?

Answer 29

decreases the circulatory capacity for the same amount of blood, increasing the pressure

Question 30

why is kidney filtration important for bp? 5

Answer 30

• 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

Question 31

what is the filter in the kidney called? what is the filtration unit called?

Answer 31

glomerulus (1 million per kidney)

nephron

Question 32

what is glomerular filtration rate? 3

Answer 32

• fluid entering all bowman’s capsules under the glomerulus
• in ml/min
• increase leads to fluid loss in urine

Question 33

what is the input to the glomerulus?

the two outputs?

Answer 33

• afferent arteriole

- bowman’s capsule or efferent arteriole

Question 34

what is hypoxia
anoxia
hypoxaemia

Answer 34

• insufficient oxygen supply to tissues
• no oxygen supply
• insufficient oxygen supply to the whole blood system

Question 35

what is ischemia?

Answer 35

insufficient blood flow to a region

always leads to hypoxia

Question 36

what is angina pectoris? 3

treatment? 2

Answer 36

• 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

Question 37

what is myocardial infarction? 4

treatment?

Answer 37

• death of one region in the heart
• sudden crushing pain
• occlusion of coronary artery
• immediate reperfusion (PCI)

-MONA
morphine
oxygen 
nitrates
aspirin

Question 38

what is heart failure? 5

Answer 38

• pump failure- insufficient blood
• fatigue
• dyspnoea (difficulty breathing)
• oedema
• results from previous MI

Question 39

what is shock? 4

Answer 39

• critically low perfusion
• medical emergency
• affects critically ill patients
• affects cerebral and renal function

Question 40

what is syncope? 4

Answer 40

• loss of consciousness
• fainting due to insufficient blood flow to the brain
• not a seizure
• can be due to heart malfunction