Transport in animals 3.2

Question 1

the need for transport systems in multicellular animals

Answer 1

• larger animals have a smaller surface area to volume ratio
• have a longer diffusion distance so they cannot rely on diffusion aloneas it will be too slow the high metabolic rates of animals

Question 2

single circulatory system

Answer 2

the blood flows through the heart once for each circuit in the body

Question 3

double circulatory system

Answer 3

blood flows through the heart twice for each circuit in the body

Question 4

pulmonary circulation

Answer 4

-carries blood to the lungs to pick up oxygen

Question 5

systematic circulation

Answer 5

carries the oxygen and nutrients around the body to the tissues,

Question 6

why is having a double cirulatory system benefical for mammals

Answer 6

-Because blood pressure is reduced when being taken to the lungs to avoid damaging delicate capilaries but it would be too slow for the rest of the body so it allows blood to be carried at a high pressure around the rest of the body

Question 7

closed circulatory system

Answer 7

blood remains within the vessels

Question 8

disadvantages of open circulatory system

Answer 8

• blood pressure is low and blood flow is slow

- circulation of blood may be affected by body movements or lack of body movements

Question 9

open circulatory system

Answer 9

blood is not held within the blood vessels

Question 10

structure of the arteries

Answer 10

• thick walls to withstand high pressure
• small lumen to maintain high pressure
• inner layer(tunica intima) consist of a relatively thick layer of elastic tissue to allow the walls to stretch and recoil maintaining blood pressure
• middle layer(tunica media) consists of a thick layer of smooth muscle which controls the diameter of the artery
• outer layer(tunica adventitia) consists of collagen fibres to provide strength to withstand high pressure

Question 11

function of the arterioles

Answer 11

distribute the blood from an artery to a capillaries

Question 12

structure of the arterioles

Answer 12

• walls consists of a layer of smooth muscle which constrict the diameter of the arterioles

Question 13

structure of the capillaries

Answer 13

• thin walls one endothelium cell thick
• red blood cells squeeze against the walls of the capillary reducing the diffusion distance

Question 14

function of the venules

Answer 14

collect blood from the capillaries to the veins

Question 15

structure of the venules

Answer 15

• Has elastic tissue and collagen

Question 16

structure of the veins

Answer 16

• thin walls
• large lumen to maximise blood flow
• contains values to stop backflow

Question 17

describe the cardiac cycle

Answer 17

• Blood enters the atria via the vena cava and pulmonary vein
  -At atrial systole the atria contracts which decreases their volume and increase their pressure pushing blood into the ventricles through the atrioventricular values
• the atria relaxes(diastole). The ventricular systole occurs decreasing their volume and their pressure becomes higher than in the artful so the atrioventricular values shut and the semi-lunar values open
• blood is forced out into the pulmonary artery and aorta
• when both atria and ventricles are in diastole the semi-lunar value close

Question 18

How is tissue fluid formed ?

Answer 18

• the blood at the arteriole end of then capilary is under a higher blood pressure than at the venule end
• the hydrostatic pressure is higher than the oncotic pressure at the ateriol end
• water,dissolved solutes,glucose and amino acids are forced out of the capilaries through fenestrations
• large proteins and red blood cells stay in the blood and reduce the water potential
• the oncotic pressure is higher than the hydrostatic pressure at the venule end so water, dissolved solutes,glucose and amino acids diffuse back into the capilaries
• only about 90% the rest gos to the lympthatic system

Question 19

Oxyhaemaglobin

Answer 19

• oxygen binds reversibility to the haemoglobin.

Question 20

Describe the oxygen dissociation curve

Answer 20

• at low partial pressure(respiring tissue) the haemoglobin has a low affinity for oxygen so it has less saturated oxygen
• At a high partial pressure(e.g the lungs) Haemoglobin had a high affinity for oxygen so it has a high saturation of oxygen

The graph is an S-shape because when the first O2 molecule combines to haemoglobin it cause a conformation change making it easier for other molecules to bind too
- But as Hb becomes saturated it gets harder for more oxygen molecules to join too

Question 21

Describe the Bohr effect

Answer 21

• reduces haemoglobins affinity for oxygen
  -to prevent the build up of H+ ions in the blood Hb acts as a buffer
• therefore H+ binds with Hb forming haemoglobinic acid
  -the alters the structure of Hb
• more oxygen is released for Hb where needed

Question 22

How are hydrocarbonate ions formed

Answer 22

• carbon dioxide diffuses into the red blood cells
  -the carbon dioxide combines with water forming carbonic acid catalysed by the enzyme carbonic anhydrase
  -carbon acid dissociates to form hydrocarbonate ions and hydrogen ions

Question 23

Fetal haemoglobin

Answer 23

• has a higher affinity for oxygen at low partial pressure than adult haemoglobin
  -At the placenta there is a lower partial pressure of oxygen because some some oxygen has been used up by the mothers body so for the Cetus to survive it needs to have a higher affinity at lower PO

Question 24

Bradycardia

Answer 24

Slow heart rate

Question 25

Tachycardia

Answer 25

Fast heart rate

Question 26

Atrial fibrillation and ventricular fibrillation

Answer 26

Artia is beating more frequently than ventricles. No clear P wave seen.

• ventricular is beating more frequently= more frequent Qrs complex

Question 27

order of blood vessels

Answer 27

-arteries
-arterioles
-capilaries
-venules
-veins

Question 28

how to discet a heart

Answer 28

-use a scapel to cut from the ventricle up thrpugh to the artium to be able to see both sides od the heart

Question 29

how is heart action initiated and coordinated

Answer 29

-SAN initiates a wave of excitation
-wave spreads over atrial walls
-this causes the atria to contract
the contaction is synchronised
-The wave of ecitation passes to the AVN which causes a delay to ensure the atria is fully emptied
-excitation spreads down the Bundle of is to the purkyne tissues surrounding the ventricle walls
-this causes the ventricles to contract

Question 30

ECG stand for

Answer 30

• Electrocardiogram

Question 31

What does the letter stand for in a EEG

Answer 31

P- atria contraction
- QRS complex ventricular contraction
T- ventricles relax

You can compare between the start of a P wave and T wave

Question 32

Explain the chloride shift

Answer 32

-Hydrocarbonate ions leave the red blood cells
- to balance out the charge Chlorine ions are diffused into the red blood cells

Question 33

Describe the role of haemoglobin in transporting oxygen around the body

Answer 33

-Hb has a high affinity for oxygen
-oxygen bind to Hb in the lungs
- oxyhameoglobin is formed
-oxygen is released where needed