Transport in animals

Question 1

Why do animals need large transport systems

Answer 1

Have high metabolic demands
Need large supply of O2
Diffusion alone not sufficient
SA:Vol to low
Wastes need to be removed from body

Question 2

Difference between single and double circulatory system

Answer 2

In single - blood flows through heart once for single circuit of body but
In double blood flows through heart twice for single circuit of body

Question 3

Difference between open and close circulatory system

Answer 3

Blood contained within vessels in close and not in open

Question 4

Issues with single circulatory system + advantages of double circulatory system

Answer 4

Low bp after capillaries in gills but blood still needs to flow to rest of body
Further inc in pressure = gills rupture
Lack of pressure = lack of flow rate

ADV
Bp in pulmonary system can be maintained at lower lvls than systemic to protect capillaries lungs
Systemic bp high = transport gases + nutrients

Question 5

Compare artery to vein

Answer 5

Artery = smaller diameter, less collagen, more elastic tissue + muscle

Question 6

Artery: Function + structure

Answer 6

Carry blood away from heart - high pressure

Thick elastic layer - withstand pressure + stretch recoil
Collagen - support
Smooth muscle - change shape - control blood pressure + strength to withstand pressure

Question 7

Veins: Function + structure

Answer 7

Carry blood to heart - less pressure

Thin elastic layer
Valves - prevent back flow
More collagen than artery - structural support - since carries large vols of blood

Question 8

Capillaries: Function + structure

Answer 8

Allows substance exchange between blood + tissue fluid

Wall = one cell thick - short diffusion distance
Large enough to allow only RBCs
Small enough to form network

Question 9

Formation of tissue fluid

Answer 9

Arterial end = high hydrostatic pressure
Plasma out capillary - through fenestrations
Fluid that leaves = plasma, containing nutrients + O2
Hydrostatic > oncotic

Question 10

What is tissue fluid made of

Answer 10

O2, CO2 + some WBCs

Question 11

2 ways in which blood plasma is different to tissue fluid

Answer 11

No erythrocytes
No large plasma proteins

Question 12

What is filtration pressure

Answer 12

HP - OP

Question 13

Lymph fluid compared to tissue fluid

Answer 13

Less O2
Fewer nutrients
More CO2
More waste products
More fatty material from intestines

Question 13

Lymph fluid compared to tissue fluid

Answer 13

Less O2
Fewer nutrients
More CO2
More waste products
More fatty material from intestines

Question 14

What does the LHS + RHS of heart pump for

Answer 14

LHS = systemic circulation
RHS = pulmonary circulation

Question 15

Why does LV have thicker walls than RV

Answer 15

Blood pumped further distance in LV (around body)
So thicker walls to create higher pressure

Question 16

Types of valves in heart
Location
Number of cusps

Answer 16

Atrioventricular
Between atria + ventricle
Tricuspid - RHS
Bicuspid - LHS

Semilunar
Aorta + pulmonary artery
(prevent backflow into ventricles)
Bicuspid

Question 17

What causes the lub-dub sound in the heart

Answer 17

Lub = closing of bicuspid valve
Dub = backflow of blood closing semi lunar valves

Question 18

Events of cardiac cycle

Answer 18

Atrial diastole
Atria relax
Blood enters atria
Ventricular diastole
Ventricles relax
Blood flow through AV valve - open
Blood enters both atria + ventricle

Atrial systole
Atria contracts
Inc pressure atria
More blood flow through AV
Ventricles fill more
Vol + pressure inc in ventricles

Ventricular systole
Ventricles contract
Vol in ventricle = dec
Pressure inc
AV = close
SL = open
Blood flow into - aorta + pulmonary artery

Question 19

Function SAN

Answer 19

Sends wave of excitation
To signal cardiac muscles in atria to contract
Initiates heart beat

Question 20

How is the wave of excitation from SAN prevented from reaching ventricles

Answer 20

Layer of non conducting tissues
Between atria + ventricle
Prevent wave travelling further

Question 21

Role of AVN

Answer 21

Delays contraction
To allow ventricles to fill
(Passes signal from SAN to AVN)

Question 22

How does AVN send signals to ventricle

Answer 22

Signal sent down bundle of His + purkyne fibres
To apex of heart + around external ventricle walls

Question 23

P
QRS
T

Answer 23

P = atrial systole (SAN excitation)
QRS = ventricular systole
T = diastole

Question 24

What does the distance from P to R show

Answer 24

Time taken for SAN signal to travel to AVN and down purkyne fibres

Question 25

Cardiac output =
(Units)

Answer 25

stroke vol x heart rate
dm3 per min

Question 26

O2 dissociation curve

Answer 26

Low pO2 = low % saturation
High pO2 = high % saturation
(never 100%)

Question 27

O2 dissociation curve of Hb

Answer 27

Sharp rise
Binding of one O2 = conformational change in Hb allows further binding of O2 easily

Leveling off
Remaining Hb group difficulty associating with O2
Due to limited space

Question 28

Why is it important that fetal Hb has a higher affinity for O2 than adult Hb

Answer 28

Low pO2 in placenta
O2 passed from adult Hb to fetal Hb in placenta

Question 29

Fetal Hb on dissociation curve

Answer 29

Above + left
Fetal Hb able to associate with O2 at lower pO2
Since higher affinity for O2

Question 30

CO2 transport

Answer 30

Carbonic anhydrase catalyses reaction - carbonic acid
Dissociates into HCO3- + H+
HCO3- diffuses out into plasma
Cl- diffuse into RBC - maintain charge

Question 31

Why does RBC release more O2 in respiring tissues

Answer 31

High conc of H+
Hb higher affinity for H+ than O2
Hb disassociates from O2
Forms heamoglobonic acid
Thus releasing O2 in respiring tissues = Bohrs effect

Question 32

What determines how much affinity haemoglobin has for oxygen

Answer 32

DNA
Amino acid sequence + number (primary structure)
Folding + bonding (secondary helix structure)
Tertiary structures