Exchange and Transport in Animals (not heart or O2/CO2 transport) Flashcards
1
Q
What does ventilation do?
A
Maintains the concentration gradient necessary for passive diffusion.
2
Q
Adaptations of trachea- 2
A
incomplete C-shaped rings of strong and flexible hyaline cartilage
Smooth muscle contracts for forced exhalation
3
Q
Adaptations of Nasal cavity - 3
A
Large surface area and good blood supply.
Goblet cells secrete mucus
Moist surfaces (due to mucus)
4
Q
Adaptations of bronchi- 3
A
Cartilage supports shape
smooth muscle helps control diameter
nerves of parasympathetic (slows down) and sympathetic (speeds up) nervous systems control muscle relaxation and contraction
5
Q
Adaptations of bronchioles- 2
A
smooth muscle controls diameter
lined with cilia and goblet cells
6
Q
Adaptations of alveoli- 6
A
Very flattened epithelial layer - 1 cell thick
Good blood supply
Collagen to strengthen
Elastin for recoil
Huge numbers to maximise SA
Covered with layer of fluid to dissolve gases
7
Q
Surfactant
A
Prevents collapse and allows inflation, ensures balanced surface tension.
8
Q
Role of smooth muscle in asthma
and asthma treatments- 2
A
Cells lining bronchioles release histamines (chemicals make epithelial cells inflamed and swollen), stimulating goblet cells to make excess mucus and smooth muscle in bronchiole walls to contract. - airways narrow and fill with mucus.
Relievers- chemicals attach to active sites of surface membrane of smooth muscle cells in bronchioles, making them relax and dilate airways.
Preventers- (often steroids) taken everyday reduce sensitivity of airway linings
9
Q
What does ventilation do?
A
Maintains the concentration gradient in alveoli necessary for passive diffusion by constantly cycling fresh air. O2 levels high and CO2 levels low in alveoli.
10
Q
Three ways we can measure ventilation.
A
Observation/ counting breaths per minute
Chest belt and pressure meter
Spirometer
11
Q
Are inspiration and expiration active or passive processes?
A
Inspiration = active Expiration= considered passive
12
Q
Inspiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
A
External intercostal muscles: contract, pulling ribs UPWARDS and OUTWARDS
Internal intercostal muscles: relaxed
Diaphragm: muscles contact, causing diaphragm to flatten
Air pressure in lungs: decreases
Air movement(along pressure gradient): air moves into lungs
Lung volume: increases
13
Q
Expiration: External intercostal muscles Internal intercostal muscles Diaphragm Air pressure in lungs Air movement(along pressure gradient) Lung volume
A
External intercostal muscles: relax
Internal intercostal muscles: contract, pulling ribs INWARDS and DOWNWARDS
Diaphragm: muscles relax, causing diaphragm to curve upwards
Air pressure in lungs: increases
Air movement(along pressure gradient): air moves out of lungs
Lung volume: decreases
14
Q
What happens during forced exhalation?
A
Internal intercostal muscles contract and abdominal muscles contract, pushing diaphragm upwards.
15
Q
What feature of tissues also aids expiration?
A
Elastic recoil of tissues (bronchi/bronchioles) aids expiration.
16
Q
What causes ventilation? (not muscles)
A
pressure gradient
17
Q
Ventilation equation with units
A
pulmonary ventilation (dm3min-1) = tidal volume (dm3) x ventilation rate (min-1)
18
Q
Considerations when using a spirometer
A
- Closed system- created by water
- Use of a nosepiece
- Patient health
- Sodalime absorbs CO2 (will cause trace to go down)
- Counterbalance removes resistance for breathing
19
Q
Which part of a spirometer is mobile?
A
The upper half which is full of oxygen.
20
Q
What is the lower half of a spirometer tank full of?
A
Water
21
Q
Will the trace on a spirometer rise or fall when the patient breathes in?
A
fall
22
Q
What is vital capacity?
A
Volume of air that can be exchanged via the lungs via a maximal inhalation and exhalation.
23
Q
What is residual volume?
A
Volume of air that is always present in the lungs.
24
Q
What is tidal volume?
A
Volume of air that is exchanged via normal breathing. (one breath)
25
What factors contribute to a person's lung capacity/ventilation rate?- 3
Height
Location
Lifestyle
26
What is emphysema?
Abnormal enlargement of the alveoli, forming air spaces and lowing the overall SA.
Most commonly caused by smoking.
27
What does an insect's tough, waxy exoskeleton do and what is its effect on gas exchange?
Protects tissues and prevents water loss. There is little or no gas exchange over its surface.
28
What is the name of an insect's specialised gas exchange system?
the Tracheal System
29
What are the components of the Tracheal System?- 4
Spiracles, trachea, tracheoles, tracheole fluid
30
In resting insects, how does air move and what happens to tracheole fluid?
Air moves along trachea and tracheoles by diffusion alone. It dissolves in the moisture of walls of tracheoles and diffuses into surrounding cells. (usually adequate due to large SA)
Tracheole fluid seeps into tracheoles from surrounding fluid.
31
During activity, how is gas exchanged (including what happens to tracheole fluid) in insects?
Oxygen demand increases and lactic acid builds up in cell, lowering water potential. Water leaved tracheoles to tissues via osmosis.
32
What effect does movement of tracheole fluid during respiration have? Insects- 2
Tracheole fluid moves via osmosis into tissues, taking O2 with it.
Fluid movement also increases SA of tracheoles, allowing increased area for direct diffusion out.
33
Why can mechanical ventilation be important in insects?
Increases efficiency of respiration.
Especially important for insects that use a lot of energy flying, as requires lots of O2.
34
What structures are used for mechanical ventilation in insects?
air sacs (enlarged areas of a trachea that can change in volume)
35
How do insects mechanically ventilate?
Change in pressure/volume of air sacs
(either muscular pumping movements in thorax and abdomen changing volume of body or compression of air sacs by pumping blood around bodies)
36
What does an aquatic organism's oxygen requirements correlate to?
The complexity of its gill structure
37
What is the operculum?
A moveable gill cover that is reinforced with rays of bone and encloses the gills within an opercular cavity.
It is removed during dissection so the gills are clearly visible.
38
Name the two parts of the gills 'gill l_____' and 'gill f____' and describe their functions/ adaptations
gill lamellae= rich blood supply and large SA are main site of gas exchange
gill filaments= finger-like projections occur in large stacks called gill plates. Gill plates had a rich supply of capillaries into which O2 can diffuse. Filaments need a flow of water to keep them apart, exposing large SA for exchange.
39
Water flow in fish (naming cavities) and What causes ventilation?
Water flows into buccal and pharyngeal cavities, passes across gills to opercular cavity and out to environment through operculum.
Volume changes in the buccal and opercular cavities create pressure that are responsible for ventilation - almost continuous flow of water created.
40
How many pairs of gills are located within the pharynx of a bony fish?
four pairs
41
Each pair of gills consists of:
two gills, each with two sets of gill filaments and lamellae.
42
Which way does water flow across gill plates?
Opposite direction to blood within capillaries. This provides a countercurrent exchange mechanism.
43
What is the benefit of a countercurrent?
An O2 gradient is maintained along the length of the gill plates. Oxygen is delivered to the blood at every point along the gas exchange surface, rather than reaching equilibrium, giving lower saturation. (parallel flow= maximum 50% saturation)
44
Inspiration in fish
Muscle contraction lowers floor of pharynx, buccal cavity volume increases, pressure decreases, water enters mouth. Operculum bulges outwards, opercular valves close, pressure decreases in opercular cavity, water flows in.
45
Expiration in fish
Buccal cavity contracts, mouth closes, floor of pharynx raises, pressure increases, water forced through gill slits. Opercular cavities contract, pressure increases causing opercular valves to open, water expelled.
46
When does RAM ventilation occur in fish?
At fast swimming speeds. Swim with mouths partially open and water flows continuously over gills.
47
Two main types of circulatory system with one example of organism with each.
Open e.g molluscs, arthropods- insects
| Closed e.g vertebrates- humans
48
Specialised/ mass transport system comprises of:
A pump, a circulating transport medium, vessels to carry the transport medium
49
Why is a transport system needed?
- Metabolic rate / high metabolic demands
- SA:V insufficient
- Transporting molecules made in one region of body and required elsewhere (e.g glucose, hormones, enzymes, removal of waste products)
50
Describe an open circulatory system
Consists of a heart that pumps haemolymph through short vessels and then freely into a large cavity called the haemocoel. This is under low pressure.
The fluid comes into direct contact with the cells, allowing diffusion. When the heart relaxes, heamolymph is sucked back in via pores called ostia.
51
a small opening or orifice is called an ...
ostium
52
what is haemolymph?
a circulating fluid in the bodies of some invertebrates that is the equivalent of blood
53
What is the haemocoel?
the system of cavities between the organs of arthropods and molluscs through which haemolymph circulates.
54
Describe a closed circulatory system
Blood is enclosed in vessels, through the walls of which substances diffuse through. Blood is pumped by the heart under pressure into vessels and returns directly to the heart. The amount of blood flowing can be adjusted by widening or narrowing the blood vessels.
55
Describe a single closed circulatory system
It has one circuit from the heart.
The heart has 2 chambers as the blood only passes through once. It passes through 2 sets of capillaries: one to exchange O2 and CO2 and the other between the blood and the cells.
The pressure is low (limits exchange processes) because blood goes through two sets of narrow vessels.
56
Disadvantages of a single circulatory system- 3
Low blood pressure
Slow movement of blood
Activity level of animal tends to be low.
57
Describe a double closed circulatory system
Blood travels in two circuits through the heart: pulmonary (through lungs and back to heart) and systemic (throughout rest of body and its organs).
Heart has 4 chambers so in mammals blood is separated into oxygenated and deoxygenated.
Blood is at relatively high pressure and fast flowing.
58
Name the 5 types of blood vessel
Arteries, Arterioles, Capillaries, Venules, Veins
59
In which blood vessel does gas exchange occur?
Capillaries
60
Three components of blood vessels and their functions
Elastic fibres - made of elastin (fibrous protein), stretch and recoil, provide flexibility
Smooth muscle- contracts and relaxes, changes the size of the lumen
Collagen (fibrous protein)- structural support, maintains shape and volume
61
Structure of arteries and how this relates to function - 3
Narrow lumen relative to wall thickness: maintains high blood pressure
Thick wall containing outer layer of collagen: prevents artery from rupturing under high pressure
Inner layer of muscle and elastic fibres: maintain pulse flow by contracting and stretching to control diameter (IT DOES NOT PUMP)
62
How does the histology of an arteriole differ to an artery?
Arterioles have more smooth muscle and less elastic fibres. Rings of smooth muscle contract and constrict the diameter of the arteriole.
Arterioles have little pulse surge but can constrict and dilate to move blood flow.
63
What does elastic recoil help to do in the artery?
Helps to even out the flow of blood between pulses. It also pushes blood through the artery to maintain arterial pressure between pump cycles.
64
Structure of capillaries and how it relates to their function
Very narrow diameter (10 micrometers): reduces blood flow to allow time for more efficient exchange
Thin walls (one cell thick): provides short diffusion pathways, ensuring maximum rate.
Walls are leaky/gaps in endothelium: high permeability/ allows plasma and dissolved substances to leave the blood.
65
How is high blood pressure in arteries dissipated?
Extensive branching of vessels and narrowing of lumen.
66
Capillaries:
Continuous
Fenestrated
Sinusoidal
Continuous: endothelial cells held together by tight junctions to limit permeability of large molecules
Fenestrated: contains pores/ found in capillaries specialised for absorption
Sinusoidal: open spaces between cells and are permeable to large molecules and cells
67
Structure of veins and how this relates to their function- 3
Very wide lumen relative to wall thickness: maximises blood flow for more effective return
Thin wall containing less muscle and elastic fibres but lots of collagen: carry blood flowing at a very low pressure
Valves: prevents backflow and pooling at lowest extremities
68
What percentage of blood is usually found in veins?
Around 60%
69
How does a vein differ from a venule?
Venules have no elastin fibres or smooth muscle.
70
Which vessel only has one layer? How many do the others have?
Capillary has one layer.
Arteries and veins have 3.
71
What is an aneurysm?
A bulge or weakness in a blood vessel
72
4 functions of blood
Transport, Defence, Thermoregulation, Maintaining pH of body fluids
73
How is hydrostatic pressure involved in blood flow in capillaries?
At arteriole end, fluid exits capillary into tissue fluid because capillary hydrostatic pressure is greater than blood osmotic pressure.
At venous end, fluid re-enters capillary as capillary hydrostatic pressure is less than blood osmotic pressure.
74
What are the three main things that make up blood and percentages of each?
PLASMA (55%)
Formed elements (45%)- 98-99% ERYTHROCYTES
- 1-2% BUFFY COAT - white
blood cells and platelets
75
Where does tissue fluid come from?
Capillary beds/ The substances that leak out of blood capillaries via fenestrations
76
What does tissue fluid do?
Helps bring oxygen and nutrients to cells and to remove waste products from them
77
What other name is tissue fluid know by?
Interstitial fluid
78
Why are plasma proteins important? (in blood plasma, not tissue fluid)
They help regulate the osmotic pressure of blood.
79
The tendency of water to move into the blood by osmosis is called...
oncotic pressure ( about -3.3kPa)
80
What is oncotic pressure?
Oncotic pressure is a form of osmotic pressure exerted by proteins either in the blood plasma or interstitial fluid.
81
What is hydrostatic pressure?
Hydrostatic pressure is a force generated by the pressure of fluid on the capillary walls either by the blood plasma or interstitial fluid
82
At which end of the capillary is hydrostatic pressure highest?
Arterial end
83
Why is fluid forced out of capillary at arterial end?
Hydrostatic pressure
84
Where does the diffusion occur at the capillary?
Tissue fluid- fluid flowing out fills the space between cells
85
Why does fluid re-enter capillaries at venous end?
Hydrostatic pressure falls and pulse is lost.
86
How does tissue fluid differ from blood plasma?
Similar but NO CELLS and NO PLASMA PROTEINS in tissue fluid
87
What two forces oppose outwards pressure of blood/tissue fluid from capillaries?
Hydrostatic pressure of tissue fluid outside capillaries.
Lower water potential of the blood.
88
Why does hydrostatic pressure fall at venous end of capillary?
Tissue fluid had moved out at arterial end, decreasing volume in capillary.
89
Describe pressure at arteriole end of capillary and state direction of flow of tissue fluid.
Large hydrostatic pressure, smaller osmotic pressure outside.
Tissue fluid forced out of capillary.
90
Describe pressure at ventriole end of capillary and state direction of flow of tissue fluid.
Hydrostatic lower so osmotic pressure now higher than hydrostatic.
Tissue fluid moves into capillary.
91
Name some major lymphatic organs
Spleen, tonsils, thymus, adenoids
92
What does the lymphatic system do?
Protects and maintains body by producing and filtering lymph.- immune function and absorbs fats and fluids from across body.
93
What is lymph? What three things does it contain?
Part of tissue fluid that does not return to the capillaries. It contains tissue fluid, fatty substances, and lymphocytes.
94
How is lymph moved in larger vessels?
Muscle contraction and valves to prevent backflow.
95
How is lymph finally returned to blood?
Enters right and left subclavian veins at their junctions with respective internal jugular veins.
96
Where is lymph filtered?
Lymph nodes
97
Blood plasma to tissue fluid is called
Ultrafiltration
98
Tissue fluid to blood plasma is called
Reabsorption
99
Tissue fluid to lymph is called
drainage
100
What does a peak flow meter measure?
Fastest rate of air flow from lungs/ indication of lung function
101
Main component of insects’ exoskeleton
Chitin
