human circulatory system

Question 1

composition of blood

Answer 1

blood 55%
plasma(including wbc and platelets) 45%

Question 2

function of blood

Answer 2

–> transports oxygen, carbon dioxide and nutrients and waste products
–> protection against pathogens
–> protection against blood loss through blood clotting

Question 3

plasma
-colour of liquid?
-function

Answer 3

pale yellowish liquid
transport water, proteins and dissolved substances, co2 and waste products, blood cells and platelets around the body

Question 4

red blood cells
-structure
-function

Answer 4

biconcave, circular disc:
–> increases SA:VOL ratio to the cell, increases rate of diffusion of OXYGEN
presence of haemoglobin:
–> combines reversibly with oxygen
absence of nucleus:
–> can pack more haemoglobin and thus more oxygen can be transported

transport oxygen to other body cells

Question 5

white blood cells
-structure
-function

Answer 5

-circular and oval or irregular shape
-presence of nucleus
-some able to change shape, move and squeeze through narrow capillaries
*-produce antibodies that identify and neutralise pathogens
*-engulf pathogen

Question 6

platelets

Answer 6

just a fragment of a cell
contains clotting factors and enzymes needed for blood clotting

Question 7

mechanism of clotting!! **
-5 steps!
-small cut and deep cut diff

Answer 7

1. when there is a cut, platelets in the blood form a platelet plug by sticking to each other at the wound site
2. platelets plug cannot stop the bleeding for deep cuts effectively
3. the damaged tissue and platelets will trigger a series of enzymatic reactions to form a mesh(protein) which traps blood cells and bacteria
4. as blood clot solidifies , it forms a scab
5. scabs protects the underlying layers where new cells formed to replace damaged cells

Question 8

blood groups!! impt but refer to ipad for template

Answer 8

universal donors:
blood type O
universal receivers:
blood type AB

Question 9

blood vessels
-functions?
- thickness of walls?
-presences of valves?
-rate of blood flow?
-pressure of blood?

Answer 9

artery:
–>lumen is narrower than vein
–>transport blood AWAY from heart
–>thick, elastic, muscular wall: withstand high pressure of blooding flowing
–>no valve
–>rate of blood flow is FAST
–>pressure of blood is HIGH

vein:
–>lumen bigger
–>transports blood TOWARDS the heart
–> thick, elastic and muscular wall
–>valves present
–>rate of blood flow is SLOW
–>pressure of blood LOW

capillary:
–>one-cell thick wall
–>allow the exchange of 1. oxygen, 2. carbon dioxide, 3. nutrients and 4. waste products between tissue fluid and blood by diffusion
–> reduce the distance for higher rate of diffusion or 4 things^

Question 10

coronary heart disease

Answer 10

see ipad for reference