Animal Gas exchange & transport Flashcards
(105 cards)
1
Q
How do Amoeba undergo gas exchange?
A
Delivers oxygen to the cells by simple diffusion. (Lives in fresh water ponds (stagnant water) with a low O2 concentration: dissolved O2, diffuses freely across cell membrane)).
2
Q
How are Amoeba adapted for gas exchange?
A
Pseudopodia (extended projection of amoeba body) to increase SA:V. Has a short diffusion pathway.
3
Q
How do Flatworms undergo gas exchange?
A
Delivers O2 to cells by simple diffusion. (Lives in mostly aquatic water: dissolved O2 freely diffuses across cell membrane. Larger, more active flatworms have basic gills.
4
Q
How are Flatworms adapted for gas exchange?
A
Very thin and flat to increase SA:V.
5
Q
How do Earthworms undergo gas exchange?
A
Delivers O2 to each cell by diffusion across it’s moist skin, closed circulation and Hb to carry O2 to each cell. Lives in a damp habitat so O2 dissolves and diffuses across the body surface.
6
Q
How are Earthworms adapted for gas exchange?
A
Elongated to increase SA:V. Moist skin.
7
Q
What are common features of a gas exchange surface?
A
Large SA relative to V.
Permeable.
Mechanism to maintain diffusion gradient.
Thin.
Moist.
8
Q
How do Amphibians undergo gas exchange?
A
Terrestrial/aquatic.
Larvae live in water & have gills. The adult uses moist skin as a respiratory surface except when active, when some, (like frogs) use lungs as a respiratory surface. Undergo metamorphosis.
9
Q
How do Reptiles undergo gas exchange?
A
Terrestrial.
Reptiles have lungs as their gas exchange surface, with an in-out bellows-like arrangement. Movement of the ribs aid in the ventilation of the lungs.
10
Q
How do Birds undergo gas exchange?
A
Terrestrial.
Birds have lungs with air sacs attached as their gas exchange surface. When the bird breathes in, any air that remains in the lungs from the last breath gets sucked into the air sacs- lungs always filled with fresh air.
11
Q
What are the gas exchange organs of fish?
A
Gills
12
Q
What are Gill Filaments (and how are they adapted for gas exchange)?
A
Thin layers of cells, attached to gill arch, covered in capillaries. They provide a large SA and have a short diffusion pathway.
13
Q
What is the Gill Arch?
A
Bony structures to support the gill filaments and gill rakers.
14
Q
What is the function of the Gill Rakers?
A
They filter water and trap prey.
15
Q
What are the Gill Plates?
A
Gas exchange surface in fish.
16
Q
How does gas exchange take place in the Gill Plates?
A
The blood passes through tiny capillaries present in the gill plates.
O2 passes through the gill plates into the capillaries and CO2 passes out into the water.
Blood vessels carry oxygenated blood away.
17
Q
What are Bony Fish?
A
Covered in (waterprood) scales, no gas exchange through surface. Contain gills in the opercular cavity, have a small SA:V so have a system of internal gills.
18
Q
What are Gills?
A
Made up of numerous folds- providing a large SA- maximises gas exchange. Good blood supply & counter-current flow- maintain conc gradient. Thin layer of cells separate blood from the outside water- short diffusion pathway. Always moist.
19
Q
Does water contain a high amount of O2 and is it denser than air?
A
Water contains a relatively low amount of O2 (0-7%), is denser and more viscous than air.
20
Q
What is the process fish go through for inhalation?
A
The mouth opens.
The operculum closes.
The floor of the mouth cavity is lowered.
The volume of the mouth cavity increases and the pressure falls.
Water is pulled in.
21
Q
What is the process fish go through for exhalation?
A
The mouth closes.
The floor of the mouth cavity is raised.
The volume of the mouth cavity decreases and the pressure increases.
Water flows across the gills.
The operculum is forced open.
22
Q
What is Counter-Current flow?
A
Blood and water flow in the opposite direction. It maintains the conc gradient.
23
Q
Why is Counter-Current flow more efficient than Parallel flow?
A
Blood flowing through the gills always meets with water with a higher % sat of O2, so diffusion is constant.
24
Q
What is Parallel flow?
A
Blood and water flow in the same direction. Diffusion continues until blood and water have an equal % sat with 50% O2.
25
(Fish can also ventilate). How do they do this?
Opens mouth, gill covers shut, water flows in. Shuts mouth, opens gill covers, water flows out.
26
Compare gas exchange in bony fish with gas exchange in cartilaginous fish (sharks):
Bony fish skeleton is made of bones, whereas Cartilaginous fish skeleton is made of cartilage. Bony fish live in the sea and fresh water, whereas Cartilaginous fish just live in the sea. Bony fish contain gills in the opercular cavity, whereas Cartilaginous fish contain gill clefts. Bony fish use a counter-current system for gas exchange, whereas Cartilaginous fish use Parallel flow.
27
Why can't fish survive out of water?
When fish are out of water there is no longer water running past gill filaments (what was keeping theme separate). With fish out of water and the gill filaments still damp, H-bonds form between gill filaments and gill plates, meaning they stick together which reduces the SA for gas exchange.
28
What is the gas exchange system in insects?
Respiratory system = tracheal system. Involves diffusion of O2 directly from atmosphere into air filled sacs and tubes.
29
Explain the tracheal system in Grasshoppers:
10 pairs of spiracles; 2 pairs are thoracic and 8 pairs are abdominal. The spiracles are guarded by fine hairs and by valves that open/close the spiracles-reduces water loss. Spiracles open into long tubes: tracheae, which link to air sacs. Tracheae = fine tubes that have a wall of single layered epithelial cells. The cells secrete spiral cuticular thickenings around the tube: support (prevent tube collapsing in inspiration). Tracheal tubes branch into tracheoles-enter tissue.
30
What is the tracheal system?
A network of internal tubes that facilitate gas exchange.
Provides large SA.
Small insects rely on diffusion through the tracheal system alone.
Large insects ventilate their tracheal system by rhythmical body movements that suck air in and pump it out.
31
What are the ventilation mechanisms of insects?
Air flows in through the thoracic and first 2 abdominal spiracles and flows out through the remaining abdominal spiracles.
Air is moved by contraction and relaxation of muscles in the abdomen which change the size of the abdomen and cause pressure changes.
32
What is the process insects go through for Inspiration?
The thoracic and first 2 abdominal spiracles open. The other 6 abdominal spiracles-closed. The abdomen expands causing an increase in volume and a decrease in pressure. Air flows in.
33
What is the process insects go through for expiration?
The thoracic spiracles and first 2 abdominal spiracles close. The other abdominal spiracles are still open. The abdomen contracts causing a decrease in volume and an increase in pressure. Air flows out.
34
What happens when the spiracles open?
Air enters tracheoles.
35
Where is a Goblet cell found and what's it's function?
Found: Trachea, Bronchi, Bronchioles.
Function: Secrete mucus.
36
Where is a ciliated epithelial cell found and what's it's function?
Found: Trachea, Bronchi, Bronchioles.
Function: Waft mucus up airway to back of throat to be swallowed and bacteria killed by stomach acid.
37
Where is Cartilage found and what's it's function?
Found: Trachea, Bronchi, Bronchioles.
Function: Supports trachea and bronchi, holding them open and preventing them collapsing in inspiration. AC ring- allows oesophagus to expand when swallowing.
38
Where are Elastic Fibres found and what's their function?
Found: Trachea, Bronchi, Bronchioles, Alveoli.
Function: Stretch when inhaling, the alveoli expand increasing the SA. The fibres then recoil when breathing out-forces out more air.
39
Where is Smooth Muscle found and what's it's function?
Found: Trachea, Bronchi, Bronchioles.
Function: Adjusts size of airways. Relax during exercise and allow more air into lungs. In asthma, they contract-constriction-narrows airways = breathlessness.
40
Why is alveoli efficient for gas exchange?
Large SA.
Moist
Good blood supply-maintains conc gradient.
1 cell thick.
Permeable.
41
What is the process of inspiration in Human?
The external intercostal (rib) muscles contract, pulling the rib-cage up and out. This pulls out the pleural membrane- reduces pressure in the pleural cavity and the inner pleural membrane moves outwards. This pulls on the surface of the lungs and causes the alveoli to expand. The diaphragm contracts, pulling it from a domed to a flattened shape.
Volume of thorax and lungs increases.
Pressure is decreased.
Air enters, down the pressure gradient
42
What is the process of Expiration (relaxed) in Humans?
External intercostal (rib) muscles relax and the rib cage falls under it's own weight. Diaphragm relaxes and organs push it back to it's domed shape. Is an elastic recoil of lung tissue.
Volume of thorax and lungs decreases.
Pressure increases.
Air forced out
43
What is the process of Expiration (forced) in Humans?
Internal intercostal (rib) muscles contract, pulling the rib cage down and in. Abdominal muscle contracts- pushing the diaphragm up.
Volume of thorax and lungs decreases.
Pressure decreases
Air forced out
44
When does Expiration (forced)/ forced exhalation take place?
During exercise and singing.
45
What is an open circulatory system?
Blood not always held within blood vessels and can circulate through the body cavity so that cells are immersed directly in the blood. Little control over direction of circulation. Movement of muscles assist with the movement of blood back into the head region. No respiratory pigment-insect blood doesn't carry O2. Blood pumped at low pressure and slower.
46
Where are open circulatory systems found?
Insects.
47
What is a closed circulatory system?
Blood enclosed within vessels. Tissues aren't in direct contact with the blood, tissue fluid exits capillaries and bathes the cells- allows heart to pump at a higher pressure. Blood flow- more rapid and efficient. Blood flow can be directed to where it's needed, by vasoconstriction and dilation.
48
Where are closed circulatory systems found?
worms.
49
What is a single circulatory system?
Blood stays in vessels on a single pathway around the body. Blood only passes through heart once before returning to gills. Blood transported to body has been oxygenated at the gills. Slower rate of blood flow.
50
Where are single circulatory systems found?
Fish
51
What is a double circulatory system?
Heart pumps blood and it goes through heart twice because: mammals are endothermic (produce own body heat) so have high metabolic rate and energy requirement so cells need large amounts of glucose and O2 and the removal of waste products (CO2). Blood flows quicker to body tissues. More efficient delivery of O2 and nutrients to body tissues. Systemic-carry blood at higher pressure.
52
What are the two components involved in a double circulatory system?
Pulmonary Circulatory System: Heart-Lungs-Heart.
Systemic System: Heart-Body-Heart.
53
Where are double circulatory systems found?
Mammals
54
What is the function of the Vena Cava?
Returns blood from all organs except lungs.
55
What is the function of the Pulmonary Artery?
Distributes blood to the lungs.
56
What is the function of the Pulmonary Vein?
Returns blood from the lungs.
57
What is the function of the Aorta?
Distributes blood to all organs except lungs.
58
What is the function of the Right Atrium?
Receives blood from body organs and pushes it into the ventricle.
59
What is the function of the Right Ventricle?
Receives blood from the atrium and pushes it to the lungs.
60
What is the function of the Left Atrium?
Receives blood from the lungs and pushes it into the ventricle.
61
What is the function of the Left Ventricle?
Receives blood from the atrium and pushes it to the body.
62
What is the function of the Right Atrioventricular valve?
Stops blood flowing back into the atrium as the ventricle contracts.
63
What is the function of the Left Atrioventricular valve?
Stops blood flowing back in to the atrium as the ventricle contracts.
64
What is the function of the Semilunar Valve?
Stops blood flowing back into the ventricles as the ventricle relaxes.
65
What is the Mammalian heart?
A 4 chambered pump for both pulmonary and systemic circulatory systems. Double pump working synchronously keeping oxygenated and deoxygenated blood separated. Is a cardiac muscle- myogenic- beats from within the muscle itself - never gets tired- doesn't need to rely on nervous system.
66
What is an Artery?
Muscular-walled blood vessel, carrying oxygenated (high pressure) blood away from the heart to body.
67
How is an Artery adapted for it's function?
Thick walls- resist and sustain high pressure. Elastic- 'pulse' in arteries cause stretching and recoiling- smooths flow. Narrow lumen- maintain high pressure.
68
What is a Vein?
Returns deoxygenated (low pressure) blood to the heart from the body and lungs.
69
How is a Vein adapted for it's function?
Thin walls and large lumen- pressure reduced. Have Valves- prevents backflow. Outer layer of collagen- resist stretching.
70
What is a capillary?
Connect small arteries with small veins and allows exchange of materials with the tissues.
71
How are Capillaries adapted for their function?
'Leaky' (pores and gaps)- allows exchange of materials. Narrow- slow moving blood (allows time for exchange). Single layer of epithelial cells- short diffusion distance.
72
What are the 3 stages of the Cardiac Cycle?
-Diastole.
-Atrial Systole.
-Ventricular Systole.
73
What is Diastole?
The atria and ventricular muscles are relaxed. This is when blood will enter the atria via the vena cava and pulmonary vein. The blood flowing into the atria increases the pressure within the atria.
74
What is Atrial Systole?
The atrial muscular walls contract (because SA node regularly generates a wave of depolarisation), increasing the pressure further. This causes the AV valves to open and blood to flow into the ventricles. The ventricular muscular walls and relaxed (Ventricular Diastole).
75
What is the Ventricular Systole?
After a short delay, the ventricle muscular walls contract (because AV node sends a wave of depolarisation down the Bundle of His where it spreads the depolarisation up the walls of the 2 ventricles via the Purkinje Fibres) , increasing the pressure beyond that of the atria. This causes the AV valves to close and the SL to open. The blood is pushed out of the ventricles into the arteries (pulmonary and aorta).
76
What is Cardiac output?
Cardiac Output (volume of blood that leaves one ventricle in one minute) = heart rate (bpm) x stroke volume (volume of blood that leaves the heart each beat).
77
What causes the heart to contract?
SA node (in wall of right atrium) acts as a pacemaker by regularly generating a wave of depolarisation, causing the heart muscles to contract.
78
When do Valves open and close?
If the pressure behind the valves is higher than in front of the valve = valve is open.
If the pressure in front of the valve is higher than behind the valve = valve is closed.
79
When do the AV valves open?
Open when the pressure is higher in the atria than the ventricles.
80
When do the SL Valves open?
Open when the pressure is higher in the ventricles compared to the arteries (pulmonary and aorta).
81
What happens at the arteriole end in the formation of tissue fluid?
Hydrostatic pressure is high due to contraction of the left ventricle. The water potential of the blood is lower than the tissue fluid so water will want to enter the blood by osmosis. However, the HS pressure is higher than the osmotic pressure and therefore there is net movement of fluid out of the capillary and into the TF. The TF will now be high in glucose, ions, O2 and amino acids. However the blood will still contain RBCs, WBCs and the large plasma proteins.
82
What happens in the middle of the capillary bed (at the exchange part) of the formation of tissue fluid?
The cells will take in the glucose and O2 by diffusion and use it for aerobic respiration. The amino acids will be used in the cells to make new proteins. This ensures a conc gradients in maintained. CO2 and any other wast products will diffuse into the TF.
83
What happens at the Venous end during the formation of tissue fluid?
HS pressure is low due to loss of fluid from the capillary. The water potential of the blood is lower than the TF due to the retention of the large plasma proteins in the blood. So water will want to enter the blood by osmosis. This time the osmotic pressure is greater than the HS pressure, therefore there is net movement of fluid into the capillary by osmosis. The fluid returning into the capillary is high in waste products (including CO2). This will be returned to the heart via the vena cava and then to the lungs via the pulmonary artery.
84
What is the lymphatic system?
Normally 90% of the TF is returned to the capillary at the venous end. The excess drains into the lymphatic system. This fluid travels in the thoracic duct to the subclavian vein where it is returned to the blood.
85
What is Plasma?
A fluid that contains any solutes e.g glucose and soluble hormones.
86
What are Electrocardiograms (ECGs)
They measure the electrical activity of the heart. This can be measured by placing electrodes on the surface of the chest.
87
What are P waves in an ECG?
When the atria contracts (atrial systole).
88
What are the T waves of an ECG?
Relaxation of the ventricles/ the heart (diastole). Repolarisation of the heart.
88
What are the QRS complexes in an ECG?
Rapid depolarisation of the ventricles, causing the ventricles to contract (ventricular systole).
89
What should you see in a normal sinus rhythm on an ECG?
Complexes normal-evenly spaced. Rate 60-100 bpm.
90
What would you see in Asystole on an ECG?
A flat line on an ECG. No contraction or observable electrical activity.
91
What would you see in Arrhythmia on an ECG?
Without rhythm. All complexes are normal.
92
What would you see in Bradycardia on an ECG?
Heart rate slower than 60 bpm. Complexes normal and evenly spaced.
93
What would you see in Atrial Fibrillation on an ECG?
Chaotic electrical activity in atria, only QRS can be seen clearly.
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What would you see in Ventricular Fibrillation on an ECG?
Chaotic electrical activity in ventricles. No regular pattern of any sort can be seen.
95
What would you see in Tachycardia on an ECG?
Heart rate faster than 100 bpm. Complexes normal and evenly spaced.
96
Why are oxygen dissociation curves S shaped?
Cooperative binding- ppc on the Hb help to hold the haem groups in place and help load the O2-when the 1st haem group combines with O2, this changes the shape of the HB, relaxing the structure and allows 2 more haem groups to load O2 easily. Once 3 O2 molecules have combined with Hb, the molecule doesn't change shape, making it very difficult for the 4th O2 molecule to load.
97
What is the significance of the S shape of an oxygen dissociation curve?
Small change in ppo2 results in large change in % saturation of Hb with O2. More efficient unloading of O2 to the respiring cells/tissues = can reach high levels of % sat at lower ppo2 than you would in the linear curve (in the lungs).
98
What does it mean if the graph has shifted to the left?
Higher affinity for O2 than the human. Hb can become more highly saturated at lower ppo2, as the Hb loads the O2 more readily at these lower ppo2. However Hb can only unload at much lower ppo2.
99
What does it mean if the graph has shifted to the right?
Bohr Effect. Hb has a lower affinity for O2 (compared to normal-figures on graph). So, O2 dissociates more readily from Hb to respiring body cells for aerobic respiration. More respiration= more CO2= increased H+ ions= more acidic/lowers pH - alters bonds in protein (Hb).
100
What is Myoglobin?
Has a much higher affinity for O2 than Hb. Mb can load O2 from Hb and store it in muscles. Mb unloads O2 at much lower ppo2. Much lower ppo2 can only occur during exercise. Acts as an O2 store and will only dissociate it when low ppo2- can maintain aerobic respiration for longer.
101
Explain the transport of CO2 in the blood:
CO2 (produced by respiring tissues) enters the RBC by diffusion down a conc gradient. Carbonic Anhydrase catalyses the reaction between CO2 and H2O to form Carbonic acid. Carbonic acid dissociates into H+ ions and hydrogen carbonate ions (-). Hydrogen Carbonate ions diffuse out of RBC. Chloride ions diffuse into RBC to maintain electrochemical neutrality= Chloride Shift. H+ ions combine with Oxyhaemoglobinic acid (HHb), releasing O2. O2 diffuses out of the RBC into the plasma.
102
What does training at high altitudes do?
Produce more RBCs.
103
What are the 3 ways CO2 is transported in blood?
-5% dissolved in plasma as CO2.
-10-20% = CO2+HB-carboaminohaemoglobin
-75-85% CO2 is converted into hydrogen carbonate ions in RBC- then transported in plasma.
105
