Mass Transport Flashcards
1
Q
name the functions of these blood vessels: arteries, arterioles, capillaries and veins
A
art = carry oxygenated blood away from heart arteri = control blood flow to capillaries capil = link art to veins and carry out exchange vein = carry deoxygenated blood back to heart
2
Q
why do arteries have thick muscle layer (compared to veins) and thick walls?
A
muscle layer = allow constrict and dilate/recoil to control volume of blood thru them
thick walls = resists bursting under pressure
3
Q
why do arteries have a thick elastic layer (compared to veins)?
A
because it maintains high pressure thru stretching in systole/recoiling in diastole
4
Q
why is there the aortic SLV but no other valves in arteries?
A
SLV prevents backflow of blood back into left ventricle. No other valves as blood under high pressure
5
Q
why do arterioles have thicker muscle layer compared to arteries?
A
- contraction = constriction of lumen, increase pressure
- recoils = decrease pressure
- helps to control blood flow to capillaries
6
Q
why do arterioles have a thinner elastic layer compared to arteries?
A
blood is at lower pressure so reduced risk of bursting
7
Q
why to veins have a thinner muscle layer and elastic layer compared to arteries?
A
muscle: constriction/dilation of lumen does not control blood flow
elastic: blood low pressure, low risk of bursting so no recoil
8
Q
why are valves present in veins?
A
prevents backflow as blood under low pressure, ensure pressure directed to heart
9
Q
why are capillaries 1 cell thick and what is this called?
A
called endothelium: short diffusion pathway = rapid diffusion
10
Q
why is there lots of capillaries and why are they highly branched?
A
large SA for exchange
11
Q
why do capillaries have narrow diameter and lumen?
A
permeate tissues (no cell far from them) = reduces diffusion pathway
12
Q
why to capillaries have spaces between their endothelial cells?
A
allow white blood cells to escape and deal with infection in tissue
13
Q
what are capillary beds and why important?
A
a network of capillaries:
- blood flow is slow = increase time for diffu.
- large SA = increase rate of exchange
- exchange of nutrients, hormones, gases and wastes
14
Q
what is tissue fluid?
A
- blood plasma minus the plasma proteins and erythrocytes (red blood cells)
- bathes all tissues
- transport medium between blood and cells (supplies H2O, amino acids, fatty acids, glucose and receives CO2, waste material)
15
Q
what is the difference between tissue fluid and lymph?
A
lymph: excess tissue fluid without nutrients more fatty acids and CO2, less O2
16
Q
capillaries narrow than arterioles so pressure builds up this is called ________ _____and this causes tissue fluid to _____ ____ of blood plasma
A
- hydrostatic pressure
2. move out
17
Q
name the 2 factors that oppose the outward hydrostatic pressure (tissue fluid)
A
- hydrostatic pressure of tissue fluid on capillaries from outside
- lower H2O potential due to plasma proteins (too large to leave capillaries)
18
Q
when tissue fluid is pushed out of capillary by the _______ _______ it leaves the cells and ______ as they are too ______. This is called _________.
A
- hydrostatic pressure
- proteins
- large
- ultrafiltration
19
Q
Return of tissue fluid to circulatory system:
- loss of tissue fluid at _________ end ______ hydrostatic pressure in them.
- ________ end of capillary: hydrostatic pressure ______ outside the capillary so _____ is forced ____ capillary
- plasma still has _____ so has a ______ water potential than tissue fluid
- so water _____ tissue by ________ down a conc. gradient
- remaining tissue fluid enters _________ ______ which will drain back into ____ close to the ____.
A
- arteriole, reduces
- venule, higher, water, into
- proteins, lower
- leaves, osmosis
- lymphatic system, veins, heart
20
Q
how is the contents of the lymphatic system moved? (2 ways)
A
- hydrostatic pressure of tissue fluid that left capillaries
- contraction of body muscles
21
Q
describe the primary, secondary, tertiary and quaternary structure of haemoglobin
A
pri = sequence of amino acids sec = alpha helices ter = folded into a precise 3D shape quat = 4 polypeptide chains (2 alpha and 2 beta chains) and 4 haem groups
22
Q
1 haemoglobin can:
carry ___ oxygen molecules
carry ___ oxygen atoms
A
4 molecules
8 atoms
23
Q
the haem group is an ____ ion and only binds with ___ oxygen _______.
A
iron, 1 , molecule
24
Q
red blood cells are also called…
A
erythrocytes
25
why do erythrocytes not have any nucleus? (2 reasons)
more room for haemoglobin, increases oxygen carrying capacity
26
why do erythrocytes have a biconcave shape? (2 reasons)
- scrapes edges along capillary wall (shorter distance for diffu.)
- if spherical shape: haemoglobin too far from membrane = less diffu.
27
why do erythrocytes have an increased SA:V? (2 reasons)
- increases SA where O2 can diffu.
| - all haemoglobin molecules close to cell surface membrane = reduces diffu. pathway
28
why are erythrocytes flexible?
bend/squeeze thru narrow capillaries
29
role of haemoglobin?
transport oxygen from lungs to respiring tissues
30
definition of affinity
chemical attraction between molecules which results in the formation of a new molecule
31
what is loading/associating? where does it occur? and what affinity?
- process by which haemoglobin binds with O
- in the lungs/alveoli
+ high affinity with O
32
what is unloading/dissociating? where does it occur? and what affinity?
- process by which haemoglobin releases O
- occurs at tissues
+ low affinity with O
(respiring tissues produce CO2, carbonic acid = decreases pH of blood plasma = changes the shape of haemoglobin = O released)
33
name the 2 reasons why organisms have different haemoglobins
1. different environmental conditions i.e. altitude
| 2. slightly different tertiary and quaternary structure = different binding properties
34
llamas live at high altitude where the pO2 is ____. so their haemoglobin has a ______ affinity and loads _____ O2. Their curve shifts to the _______ of the human one.
1. low
2. higher
3. more
4. left
35
definition of partial pressure
pressure that would be exerted by 1 gas in a mixture if it occupied the same volume on its own
36
where is the pO2 the highest and where is it the lowest? and what does it cause?
```
highest = lungs (loading)
lowest = blood circulation/respiring tissues (unloading)
```
37
what is haemoglobin called when its saturated with oxygen?
oxyhaemoglobin
38
explain positive cooperativity
1. binding of 1st O2 molecule hard, polypeptide subunits close together
2. 1st molecule binds, easier for 2nd and 3rd = changes quaternary structure slightly
3. 4th molecule hard to bind = less likely to bind as most binding sites occupied
39
The further left the curve....
the greater the affinity of haemoglobin for O (so loads more readily but unloads less easily)
40
what does the Bohr shift show?
influence of CO2 conc. on O2 dissociation curve
- o2 has lower affinity with haemoglobin in presence of CO2
- increase CO2, increase unloading
41
in humans normally not all __ binding sites filled (normally ___% saturation). Low_______ tissue normally __ molecule ____ released (75% saturated back to lungs). Lots of ______ usually ___ molecules ______.
1. 4
2. 97
3. respiring
4. 1
5. unloaded
6. respiration
7. 3
8. unloaded
42
why do large organisms need a transport system? (3 reasons)
- cells need constant supply of O2/nutrients
- constant removal of CO2
- large animals small SA:V so diffu. too slow
43
the smaller the SA:V the ____ active the organism is so a _____ is needed
more, pump
44
name the reasons why H2O and a closed system is used in transport systems
```
H2O = readily dissolves substances/moved around easily
closed = blood confined to vessels/forms branching network which distributes to all parts
```
45
why is a mechanism for moving transport medium important in transport systems?
- requires a pressure difference (hight to low)
| - pump (animals), evap. (plants)
46
what does it mean by a double circulatory system and why is it important?
blood passed thru heart twice, as when it comes back from lungs pressure low. 2nd pump increases pressure which is needed to pass blood around body to tissues.
47
what is the name of the artery and the vein for the kidneys?
renal artery and renal vein
48
The heart:
1. Right side: ________ blood from body via ____ ____
2. Left side: _______ blood from lungs via _______ ______.
3. The _________ valves are located on both sides of the heart (______ on the left and ______ on the right).
1. deoxygenated, vena cava
2. oxygenated, pulmonary vein
3. atrioventricular , bicuspid, tricuspid, atria
49
why are the ventricle walls thicker than atria walls?
need to contract strongly to pump blood to lungs/body, increasing pressure
50
what is the role of coronary arteries and what is a myocardial infarction?
- supply oxygenated blood to heart for respiration
+ heart attack, happens when coronary arteries blocked
+ area of heart deprived of O2 = unable to respire
51
name the risks associated with cardiovascular disease?
- smoking
- high blood pressure
- Diet (lots of low-density lipoproteins)
52
describe what happens in diastole (atrial and ventricular)
1. heart muscles relaxed
2. atria fills with blood
3. SLV close (prevents backflow of blood into ventricles)
4. pressure in atrium exceeds that of ventricles = AV open
53
describe what happens in atrial systole
1. walls of atria contracts
2. blood forced into ventricles
3. walls of ventricles relaxed
54
describe what happens in ventricular systole
1. ventricles contract
2. AV shut (tendons prevent inversion)
3. pressure in ventricles exceeds blood vessels = blood thru SLV
4. pressure in aorta/pulmonary artery exceeds ventricles = SLV close
55
The haemoglobins are a group of _______ similar molecules found in many different __________.
chemically, organisms
56
Haemoglobin is a _______with a __________structure.
protein, quaternary
57
the further right the curve....
the lower the affinity of haemoglobin for O (loads less easily but unloads more easily)
58
Shape of human O dissociation curve:
1. why is the gradient of the curve initially shallow?
2. Why does the gradient steepen?
3. Why does it flatten out?
due to positive cooperativity:
1. difficult for 1 O to bind
2. easier for 2nd/3rd
3. spaces occupied
59
for the Bohr shift: what happens at the gas exchange surface and what direction does the curve shift?
- O readily loaded
| - dissociation curve shifts to the left
60
for the Bohr shift: what happens at respiring tissues and what direction does the curve shift?
- O readily unloaded
| - dissociation curve shifts to the right
61
more respiration....
- more CO2 produced = lower the pH
| - greater haemoglobin shape change = more readily O unloaded
62
when the tide goes out H2O left in burrow has low O levels. How is the lugworm's haemoglobin adapted to this?
- haemoglobin can load O more readily/easily at low pO2
| - dissociation curve shifts to left of humans
63
what 2 things determine if a transport system needs a pump?
- the SA:V
| - how active the organism is
64
why is unidirectional flow important in a transport system?
maintains mass flow movement in one direction i.e. valves
65
importance of a closed, double circulatory system?
```
closed = blood confined to vessels
double = blood passed thru heart twice (increases pressure for blood to pass thru body, so keep high temp + metabolism)
```
66
name the blood vessels that:
1. enter the heart
2. leave the heart
3. enter the lungs
4. leave the lungs
5. enter the kidneys
6. leave the kidneys
1. vena cava
2. aorta
3. pulmonary artery
4. pulmonary vein
5. renal artery
6. renal vein
67
why does the heart have 2 adjacent pumps?
- to keep oxygenated/deoxygenated blood separate
| - to keep the pressure high
68
How does smoking increase risk of cardiovascular disease?
- nicotine stimulates adrenaline = increase heart rate/pressure
- CO reduces O2 carrying capacity
69
how does high blood pressure increase risk of cardiovascular disease?
heart works harder to pump blood into arteries = more likely for arteries to have aneurysm + burst or become thicker (restricting flow)
70
how does diet increase risk of cardiovascular disease?
(lots of low-density lipoproteins) = transport cholesterol from liver to artery walls
71
why do atrioventricular valves close?
prevent the backflow of blood from ventricles into atria as pressure in ventricles exceeds that of atria
72
role of the Semi lunar valves
prevents the backflow of blood from aorta/pulmonary artery into the ventricles as the pressure in them exceeds that of ventricles
73
role of pocket valves and where they located?
- located in veins in venous system
| - blood flows towards the heart
74
what is cardiac output?
volume of blood pumped by 1 ventricle of the heart in 1 min
75
how id cardiac output measured?
heart rate x stroke volume (volume of blood pumped out of heart at each beat)
