TRANSPORT IN ANIMALS (3.1.2) Flashcards
1
Q
Why do multi-cellular organisms require transport systems
A
- low SA:V volume
- high metabolic rate
- movement of substances around the body (e.g. hormones, antibodies)
2
Q
What is the single circulatory system
A
Blood passes through the heart once to complete a circuit
3
Q
Describe the circulatory system of a fish
(Single or double)
A
- single circulatory system
- heart pumps blood to the gills for O2
- blood then carries O2 to the rest of the body in one single circuit
4
Q
What is a double circulatory system
A
When blood passes through the heart twice
5
Q
Describe the circulatory system of a mammal
(Single or double)
A
- double circulatory system
1. Right side of the heart pumps blood to the lungs to pick up O2
2. Oxygenated blood travels back to the heart
3. Left side of the heart pumps the blood around the body to deliver O2
4. Deoxygenated blood returns to the right side of the heart
6
Q
What is a closed circulatory system
A
- all vertebrates have this
- blood is enclosed inside blood vessels
7
Q
Describe the circulatory system of a fish
(Closed or open)
A
- Heart pumps blood into arteries, branching into capillaries
- Oxygen glucose etc diffuse from blood inside capillaries into body cells
- Veins take blood back to the heart
- blood remains inside the vessels as it circulates
8
Q
What is an open circulatory system
A
- some invertebrates
- blood flows freely in the body cavity and is not enclosed in blood vessels
9
Q
Describe the circulatory system of an insect
(Open or closed)
A
- Segmented heart contracts in a waves, pumping blood into single main artery
- Artery opens into body cavity
- Blood flows freely around organs, making its way back into heart segments through valves
- this supplies nutrients, not O2 (this is done by the tracheal system)
10
Q
Describe the structure of an artery
A
- folded endothelium
- elastic fibres
- smooth muscle
- collagen fibres
11
Q
describe the structure of an arteriolar
A
- endothelium
- smooth muscle
- fewer elastic fibres
- collagen fibres
12
Q
Describe the structure of capillaries
A
- one cell thick endothelium
13
Q
Describe the structure of venules
A
- endothelium
- (sometimes) smooth muscle
- few collagen fibres
14
Q
describe the structure of veins
A
- thinner endothelium
- smooth muscle
- few elastic fibres
- collagen fibres
- valves
15
Q
State the function of the endothelium
A
- allows expansion
- maintains high pressure
- reduces friction
16
Q
State the function of elastic fibres
A
Stretch and re-coil to maintain high pressure
17
Q
state the function of smooth muscle
A
Thick to maintain high pressure
18
Q
State the function of collagen fibres
A
Resist pressure
19
Q
describe the pathway of blood through vessels from the heart
A
- Arteries
- Arteriolar
- Capillaries
- Venules
- Veins
20
Q
How do you work out heart rate (bpm)
A
60 / time taken for one heartbeat (s)
21
Q
What is the normal range for a heart rate
A
60 -100 bpm
22
Q
- what is it called when a heartbeat is too fast
- what is the bpm?
A
- tachycardia
- 120bpm
23
Q
- what is it called when a heartbeat is too slow
- what is the bpm
A
- bradycardia
- 50bpm
24
Q
What is an ectopic heartbeat
A
An extra heartbeat caused by an extra contraction
25
What is fibrillation
Very irregular heartbeat where the atria or ventricles completely lose rhythm
26
What do the P WAVE, QRS COMPLEX, T WAVE show on an electrocardiograph
P WAVE - atria contraction (depolarisation)
QRS COMPLEX - ventricles contract (depolarisation)
T WAVE - everything relaxes (repolarisation)
27
Where is the Sino Atrial Node located
Right atrium
28
What is cardiac muscle explained as
- myogenic
- contracts and relaxed without receiving signals from nerves
29
Describe how electrical activity in the heart leads to a regular heartbeat
1. Sino Atrial Node sends electrical waves over atrial walls, causing both atria to contract
2. Waves pass from SAN to the Atrio Ventricular Node, due to band of non-conducting tissue
3. AVN passes waves onto bundle o His fibres after a slight pause (to ensure all blood from atria has emptied)
4. Bundle of His conduct wave down septum to Purkyne tissue in both ventricle walls
5. Purkyne tissue conducts waves to muscular ventricle walls
6. Ventricles contract from the bottom up to ensure all blood moves to the arteries
30
Where can erthyrocytes be found and why
- blood plasma
- tissue fluid
- lymph
- blood plasma
- RBC’s are too large to pass out of capillary walls
31
Where can WBC’s be found and why
- blood plasma
- tissue fluid
- lymph
- blood plasma
- lymph
- WBCs only enter tissue fluid during an infection
32
Where can platelets be found and why
- blood plasma
- tissue fluid
- lymph
- blood plasma
- too large to leave capillary walls
33
Where are most proteins found and why
- blood plasma
- tissue fluid
- lymph
- blood plasma
- few SMALL proteins in tissue fluid
- most proteins are too large to leave capillary walls
34
Where is water found
- blood plasma
- tissue fluid
- lymph
- blood plasma
- tissue fluid
- lymph
35
Where are dissolved solutes found
- blood plasma
- tissue fluid
- lymph
- blood plasma
- tissue fluid
- lymph
36
Describe tissue fluid
- where it is found
- what it is for
- what it contains
- fluid surrounding tissue cells around the circulatory system
- needed for exchange of substances between cells and bloodstream (e.g. O2 into cells)
- contains substances that have been able to leave blood plasma
37
Define hydrostatic pressure
Pressure exerted by a liquid e.g. blood
38
Define oncotic pressure
- pressure exerted by plasma proteins inside a blood vessel
- lowers water potential ψ inside blood vessel
39
Describe how tissue fluid is formed
ARTERIAL END:
- ⬆️ hydrostatic pressure inside capillaries forces fluid out into space around cells, creating tissue fluid
- large proteins cannot leave the capillary
- hydrostatic pressure ⬆️ than oncotic pressure, net movement of water is out of capillary
VENOUS END:
- ⬇️ hydrostatic pressure inside capillary
- high conc. of proteins inside capillary ⬆️, generating oncotic pressure and low ψ
- ψ lower than in tissue fluid, so water re-enters
40
- what proportion of water is re-absorbed at the venous end
- what happens to the remainder
- 90% reasborbed
- remaining 10% collected by lymph vessels
41
- how is lymph formed
- what happens to it
- excess 10% tissue fluid enters lymph vessels
- valves inside lymph vessels prevent backflow
- lymph moves towards main lymph vessels and is returned to bloodstream near the heart
42
- describe the structure of haemoglobin
- what in Hb binds to O2
- globular protein
- quaternary structure
- 4 polypeptides, each having a Haem group containing iron
- haem group binds to O2
43
State an example of an area where haemoglobin has a high affinity for O2
- alveoli
- high concentration of O2, therefore high pO2
- increases affinity for O2, causing it to load onto Hb
44
State an example of an area where haemoglobin has a low affinity to O2
- respiring tissues
- low concentration of O2, therefore low pO2
- decreases affinity for O2, causing it to unload from Hb to tissues for respiration
45
- explain what is different about fetal haemoglobin on a dissociation curve
- why is this important?
- shifted to LEFT, meaning a higher affinity to O2 at the same partial pressure of O2
- affinity difference allows for fetal Hb to load the O2 that has been unloaded by the mother in the placenta, which has a low pO2
46
- explain the Bohr effect
- why is this important
- shifted to the RIGHT, meaning lower affinity to O2
- in areas of high pCO2, affinity for O2 decreases, meaning it can be unloaded to respiring tissues as a reactant
47
State the 3 ways that CO2 from respiring cells travels
- 5% dissolved in blood plasma
- 10% binds to Hb, forming carbaminohaemoglobin
- 85% diffuses into erythrocytes and reacts with water to form carbonic acid
48
What is the enzyme that catalyses the reaction of CO2 and H2O to form H2CO3 (carbonic acid)
Carbonic anhydrase
49
Outline what happens after H2CO3 dissociates into is ions
- H+ ions are mopped up by oxyhaemoglobin, forming HHb (haemoglobinic acid)
- as this happens, O2 is unloaded by the Hb
- HCO3- ions diffuse out of the RBC into plasma
- simultaneously, Cl- ions diffuse into the RBC (chloride shift) to maintain balance of charge
50
What is the chloride shift
- when Cl- ions diffuse into erythrocytes at the same time that HCO3- ions diffuse out
- maintains balance of charge between RBC and plasma
51
Describe the order of blood flow into the heart
1. Deoxygenated blood from body enters the VENA CAVA
2. Travels from R atrium into R ventricle
3. Deoxygenated blood leaves heart to lungs through PULMONARY ARTERY
4. Oxygenated blood returns to heart from lungs through PULMONARY VEIN
5. Travels through L atrium to L ventricle
6. Oxygenated blood leaves heart to body by AORTA
52
- what does the pulmonary vein carry
- where from/to
- oxygenated blood
- from lungs, to heart
53
- what does the pulmonary artery carry?
- where from/to
- deoxygenated blood
- from heart, to lungs
54
- what does the vena cava carry
- where from/to
- deoxygenated blood
- from body, to lungs
55
- what does the aorta carry
- where from/to
- oxygenated blood
- from heart, to body
