Topic 1- Lifestyle, health and risk

Question 1

as size of organism increases

Answer 1

SA:V rat decreases
diffusion distance increases
metabolic rate increases
diffusion becomes insufficient for transport

Question 2

mass transport system

Answer 2

consists of heart and circulation which moves the substances around the body
allows exachange of substances to take place

Question 3

features of MTS

Answer 3

network to move through (vessels)
medium for movement- fluid (eg blood)
-controlled direction ( eg pressure gradient created by heart)
-maintenance of speed ( eg contraction of heart/elastic recoil)

Question 4

water properties

Answer 4

polar molecule ( H+ and O- due to difference in electronegativity- one end is more pos than other)
polar solvent
transport biological molecules (many are polar so can be dissolved)
H bonding creates cohesion and adhesion( transport through xylem vessels)
H bonding is strong- high SHC - minimise temp fluctuations

Question 5

arteries

Answer 5

oxy blood -> tissues ( except PA)
small lumen
high BP
thick muscular wall- contract and relax to constrict/ dilate blood vessels
elastin ( prevent bursting)
lots of collagen fibres
smooth inner endothelial lining

Question 6

veins

Answer 6

deoxy blood to lungs (except PV)
large lumen
thinner muscle/ elastic fibres layer
valves to prevent backflow
reduced collagen fibres

Question 7

capillaries

Answer 7

very small
narrow lumen
thin endothelium- one cell thick- short diffusion pathway

Question 8

atrial systole

Answer 8

atria contract
AV valves OPEN
blood -> ventricles

Question 9

ventricular systole

Answer 9

AV valves closed
SL valves open
ventricles contract- pressure increases
blood-> aorta ( left) + RV (right)

Question 10

cardiac diastole

Answer 10

SL valves closed
all chambers relaxed
pressure decreases

Question 11

atherosclerosis

Answer 11

hardening of arteries caused by build up of fibrous plaque- atheroma
atheroma formation is large cause of many CDV diseases

Question 12

atherosclerosis development

Answer 12

endothelium damaged ( by high chol/ smoking/ HBP)
increase risk of blood clotting
leads to inflammatory response
WBCs move into artery
WBCs/chol/calcium/fibres build up
- leads to atheroma formation
plaque build up leads to narrowing of artery
- restricts blood flow
- incr blood pressure
- damage endothelial lining ( cycle )
- positive feedback

Question 13

atherosclerosis risk factors

Answer 13

genetics
age (elasticity of arteries decreases)
die (incr chol)
gender ( oestrogen makes arteries more elastic)
high BP - damage endothelium
high chol
smoking
sedentary lifestyle
obesity

Question 14

blood clotting

Answer 14

thrombosis- prevents blood loss when a blood vessel is damaged
prevents entry of disease-causing microorganisms and provides framework for repair

Question 15

series of reactions leading to blood clot

Answer 15

when BV is damages - platelets attch to exposed collagen fibres
thromboplastic released from platelets
triggers conversion of inactive prothrombin -> active thrombin ( protein -> enzyme)
calcium and vitamin K must be present for this ( clotting factors)
thrombin catalyses conversion of soluble fibrinogen into insoluble fibrin
fibrin forms fibres
- platelets and RBCs trapped to form blood clot