Circulatory/cardiovascular system - SB8

Question 1

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which way does blood in arteries flow?

Answer 1

away from the heart

Question 2

which way does blood in the veins flow?

Answer 2

to the heart

Question 3

what do arteries divide into?

Answer 3

narrow capilaries

Question 4

what are qualities of arteries?

Answer 4

• blood away from heart
• narrow tube (lumen)
• thick layer of elastic and muscle fibres

Question 5

what are qualities of veins?

Answer 5

• veins carry blood to heart
• wide tube
• thin, flexible wall

Question 7

how is a pulse created?

Answer 7

heart squirts blood into arteries at high pressures - arteries stretch and pass along artery walls

Question 8

how is blood enabled to flow smoothly?

Answer 8

muscle and elastic fibres in the artery walls cause arteries to contract again. Stretching / contracting of arteries makes blood flow smoothly

Question 9

what prevents backwards bloodflow?

Answer 9

valves

Question 10

why are only thin walls needed in viens?

Answer 10

blood flows under low pressure

Question 11

how many red blood cells is in a cubic milimeter of blood?

Answer 11

5 mil

Question 12

how many white blood cells are in a cubic milimeter of blood?

Answer 12

7,000

Question 13

how many platelets are in 1 cubic milimeter of blood?

Answer 13

0.25 mil

Question 14

what substance are cells suspended in?

Answer 14

plasma

Question 15

what substances does plasma carry?

Answer 15

glucose, CO2 and urea

Question 16

what is in red blood cells that binds with oxygen, what does it do with oxygen?

Answer 16

haemoglobin - releases O2 in tissues

Question 17

What are the physical features of red blood cells? why are they designed this way?

Answer 17

• No nucleus - more space for haemoglobin
• Shaped like discs with dips in ‘biconcave’ shape allows large surface area : volume ratio for oxygen to diffuse in and out

Question 18

What are the 2 types of white blood cell?

Answer 18

phagocytes and lymphocytes

Question 19

what is the general role of white blood cells?

Answer 19

to remove foreign cells inside you

Question 20

what do lymphocytes do to remove foreign cells?

Answer 20

produce proteins called antibodies that stick to foreign cells and help destroy

Question 21

what do phagocytes do to get rid of foreign cells?

Answer 21

surround foreign cells and digest them

Question 22

what are platelets?

Answer 22

tiny fragments of cell with no nucleus

Question 23

why do platlets produce substances?

Answer 23

needed to clot blood prevent further blood loss

Question 24

What are the 2 main features of the heart ?

Answer 24

• 4 chambers
• valves stop backwards blood flow

Question 25

what is the first step of blood pathway?

Answer 25

de-oxygenated blood enters through the vena carva (vein)

Question 26

what is the second step of blood pathway?

Answer 26

blood pumped into right atrium and passes valve into right ventricle

Question 27

what is the third step of blood pathway?

Answer 27

passes valve into pulmonary artery to bring de-oxygenated blood to lungs

Question 28

what is the fourth step of blood pathway?

Answer 28

gaseous exchange takes place in the lungs to turn de-oxygenated blood into oxygenated blood

Question 29

what is the fifth step of blood pathway?

Answer 29

blood returns through the pulmonary vein and enters left atrium of heart

Question 30

what is the sixth step of blood pathway?

Answer 30

blood goes to left ventricle through valve - blood is pumped at high pressures into aorta to carry to rest of the body

Question 31

What valve is between the right atrium and ventricle? what does it do?

Answer 31

tricuspid valve - seperates right atrium and ventricle - opens due to high pressure in atrium and prevents backwards blood flow

Question 32

what valve seperates the right ventricle and left atrium? what does it do?

Answer 32

semilunar valve - prevents backflow of blood to heart

Question 33

what valve is between the left atrium and left ventricle? what does it do?

Answer 33

bicuspid valve - seperates left atrium and ventricle and prevents backwards blood flow. opens due to pressure in left atrium

Question 34

what valve seperates the left ventricle and the aorta? what does it do?

Answer 34

semi lunar valve - stops back blood flow to heart

Question 35

How often do heart attacks occur in the UK?

Answer 35

one every 3 minutes

Question 36

when does a heart attack occur?

Answer 36

when the blood stops flowing to muscles in part of the heart - damaging them and stopping heart pumping properly.

Question 37

what can be done if the heart stops completely?

Answer 37

can be re-started usinga defribrilator

Question 38

what is controlled by impulses from the nervous system?

Answer 38

contraction and relaxation of muscles during a heartbeat

Question 39

what is heart rate?

Answer 39

the number of times the heart beats per minute

Question 40

what is stoke volume?

Answer 40

the amount of blood pulsed into the aorta in each beat

Question 41

what is stroke volume measured in?

Answer 41

litres

Question 42

what is cardiac output?

Answer 42

volume of blood pushed into the aorta each minute

Question 43

what is the equation for cardiac output?

Answer 43

stroke volume (liters /beat) x heart rate (beats per min)

Question 44

why do fit people have bigger stroke volumes and slower heart beats? - why is this important?

Answer 44

regular excercise increases the strength of the heart muscle ad ventricle sixe - so fitter people have bigger stroke volumes and slower heart beats and can achieve the same cardiac output as a less fit person - this puts less strain on the heart