Mass Transport In Animals

Question 1

Low O2 environment

Answer 1

Needs higher affinity
Dissociation curve shifts to left
“Load more oxygen into body”

Question 2

High O2 environment

Answer 2

Graph shifted to right
Organism can afford to have lower affinity
Dissociates more in tissues
“Unload more oxygen into respiring tissues”

Question 3

Smaller animals

Answer 3

Lose heat faster
Faster metabolisms
Need to unload more oxygen into cells
Graph shifted to right

Question 4

Ventricles relax, atria relax (stage 3)

Answer 4

Atria fill again due to higher pressure in vena cava and pulmonary vein
Causes pressure to increase in atria, ventricles continue to relax until pressure in ventricles lower
Blood passively flows into ventricle as AV valves open
Atria contract to repeat process

Question 5

Systole

Answer 5

Cardiac contraction

Question 6

Diastole

Answer 6

Cardiac relaxation

Question 7

Cords

Answer 7

Attach AV valves to ventricles to stop them being forced up into the atria when the ventricles contract.

Question 8

Arteries

Answer 8

Muscular and elastic tissue
Stretch and recoil as heart beats
Maintains high pressure
Endothelium folded— stretching

Question 9

Veins

Answer 9

Contain valves to prevent back flow (low pressure)
Blood flow helped by surrounding muscle contraction.

Question 10

Why water re enters at venule end of capillary

Answer 10

Lower hydrostatic pressure due to fluid loss and increased concentration in plasma proteins

Question 11

Development of Atheroma

Answer 11

Damage to endothelium
White blood cells and lipids in blood clump together under the lining (endothelium) to form fatty streaks
Builds up, along with connective tissue, hardens to form fibrous plaque
Partial blockage of artery- causes higher blood pressure and restricted flow

Question 12

Aneurysm

Answer 12

Blood travels through weakened artery at high pressure
Pushes inner layers of artery through outer elastic layer to form a balloon like swelling
Bursts to form haemorrhage

Question 13

Thrombosis

Answer 13

Atheroma can rupture endothelium, damaging it to leave a rough surface
Platelets and fibrin accumulate to form a blood clot at site of damage (thrombus)
Blocks artery
Can dislodge and block vessel elsewhere
Debris from rupture can cause another blood clot further down artery

Question 14

Factors increasing risk of CVD

Answer 14

High blood cholesterol as cholesterol is a main constituent to the fatty deposits.
Diet high in saturated fat
Smoking (nicotine increases risk of high blood pressure, CO binds to haemoglobin, decreases amounts of antioxidants in the blood (antioxidants protect cells from damage—— Atheromas)
Increased blood pressure: overweight, lack of exercise, excessive alcohol consumption

Question 15

High concentration of carbon dioxide (due to cell respiration)

Answer 15

Increases rate of oxygen unloading/ dissociation from haemoglobin
Curve shifts to the right
(Bohr effect)

Question 16

Cardiac output equation

Answer 16

Heart rate x stroke volume

Question 17

Cardiac output

Answer 17

Amount of blood pumped by the heart per minute

Question 18

Stroke volume

Answer 18

Volume of blood pumped by the ventricles per contraction

Question 19

Heart rate

Answer 19

Number of times the heart beats in a minute

Question 20

Myocardial infarction

Answer 20

Coronary arteries blocked

Question 21

CVD risk factors

Answer 21

High cholesterol diet— one of the main constituents of atheromas
Salt- increases blood pressure
Nicotine increases risk of high blood pressure
Carbon monoxide binds to haemoglobin
Smoking decreases amounts of antioxidants in the blood (protect cells from damage)—— Atheroma formation

Question 22

Safety in dissections with the scalpel

Answer 22

Carry with blade protected
Cut away from body
Cut into hard surface
Use sharp blade
Disinfect/ dispose if used scalpel as instructed

Question 23

Describe how the structure of the insect gas exchange system:
Provides cells with sufficient oxygen
Limits water loss

Answer 23

Spiracles, trachea, tracheoles
Spiracles allow diffusion of oxygen or diffusion of oxygen through trachea/ tracheoles
Tracheoles are highly branched so large surface area for exchange
Tracheole walls thin so short diffusion pathway to cells or highly branches so short diffusion pathway or tracheoles enter cells so short diffusion pathway
Tracheole permeable to oxygen/ air
Cuticle/ chitin/ exoskeleton impermeable so reduces water loss
Spiracles can close so no/ less water loss or spiracles have valves (same reasoning)
Hairs around spiracles reduce water loss

Question 24

Fish vs mammal circulatory system

Answer 24

2 chambers vs 4 chambers
Blood doesn’t return to heart after being oxygenated vs mammals
One vein vs two veins
One artery vs two arteries