Exchange Surfaces And Breathing Flashcards

1
Q

What are the three features of an efficient exchange surface

A

Large surface area, thin, permeable barrier and a good blood supply

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2
Q

Why is a large surface area a feature of an efficient exchange surface

A

To provide more space for molecules to pass through.

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3
Q

Why is a thin barrier a feature of an efficient exchange surface?

A

To reduce distance of diffusion and must be permeable to substances being exchanged.

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4
Q

Why is a good blood supply a feature of an efficient exchange surface?

A

Can bring a fresh supply of molecules to supply side or remove molecules from demand side. This maintains steep high to low concentration gradient for rapid diffusion.

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5
Q

Why do organisms with a small surface area to volume ratio need specialised exchange surfaces?

A

As the distance for diffusion is too long and diffusion would be too slow.

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6
Q

How do the lungs have a large surface area

A

Numerous alveoli to create a large surface area about 17 m²

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7
Q

How are the lungs adapted to have a thin barrier to exchange

A

To cells thick, squamous cells, narrow capillaries squeezing red blood cells against capillary wall, total barrier less than 1 Micro meter

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8
Q

How is a good blood supply shown in the mammalian gaseous exchange system

A

Blood transports carbon dioxide to the lungs ensuring the blood has a higher concentration of carbon dioxide so it diffuses out. The blood transports oxygen away from the lungs ensuring that the blood has a lower concentration so that oxygen diffuses into the blood.

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9
Q

How does ventilation give sufficient gaseous exchange

A

Breathing movements ventilate the lungs to refresh the air in the alveoli replacing oxygen and expelling carbon dioxide. This also maintains the concentration gradient

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10
Q

How is the barrier permeable the oxygen and carbon dioxide?

A

The wall of the alveolus and the wall of the blood capillary allow the diffusion of oxygen and carbon dioxide as the molecules are small and nonpolar

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11
Q

Describe structure and function cartilage?

A

Rings which supports the trachea and bronchi which prevents collapsed during inspiration. The horseshoe shape allows flexibility when food is passing down the oesophagus.

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12
Q

Describe the structure and role of ciliated epithelium

A

Lines the airways which contributes to keep in the lungs healthy by containing goblet cells

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13
Q

Describe the role of goblet cells

A

Releases mucus which traps bacteria and dirt.

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14
Q

Describe the role of smooth muscle and elastic fibres

A

Found in the bronchial wall. Smooth muscle can contract to constrict the airway. This deforms shape of elastic fibres. The elastic fibres recoil as the muscle relaxes to elongate the smooth muscle and dilate the airway.

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15
Q

The structure of the trachea and bronchi?

A

Have a similar structure however the bronchi are narrower than the trachea. Supported by rings of cartilage.

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16
Q

The structure and role of the bronchioles

A

Much narrower than the bronchi. Wall is comprised mostly of smooth muscle and elastic fibres. The smallest bronchioles ending clusters of alveoli.

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17
Q

Mechanism of inspiration

A

Diaphragm contracts moves down and becomes flatter displacing digestive organs. External intercostal muscles contract to push the ribs upwards and outwards. Volume of chest cavity is increased. The pressure drops below atmospheric pressure and air is drawn into the lungs.

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18
Q

Mechanism of expiration?

A

The diaphragm relaxes is pushed up. The external intercostal muscles relax and the ribs move downwards. The volume of the chest cavity is decreased. The pressure in the lungs increases and rises above atmospheric pressure air is pushed out of the lungs.

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19
Q

Definition of tidal volume?

A

The volume of air moved in and out in one breath usually measured at rest.

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20
Q

Definition of vital capacity

A

The greatest volume of air that can be expelled from the lungs after taking the deepest possible breath

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21
Q

How does a spirometer work?

A

A float chamber spirometer consists of a chamber of air floating on a tank of water. When a person inhales the lid moves down and when they exhale the lid is raised. These movements are recorded on a data logger

22
Q

How to find the vital capacity from a spirometer trace

A

The greatest distance between a peak and trough

23
Q

How to measure oxygen uptake

A

Mark point and A at the first trough and point b at the last. Measure the length of time between these points. Measure difference in volume between these points. Difference in volume over difference in time. Unit is dm cubed to second minus 1.

24
Q

What does the alveolus wall contain?

A

Elastic fibres

25
Q

What are the function of elastic fibres in the alveolus?

A

So the alveolus walls can stretch during inspiration but then recoil to push out air during expiration.

26
Q

What is residual volume?

A

The volume of air that remains in the lungs even after forced expiration. The air remains in the airways and alveoli

27
Q

What is oxygen uptake?

A

The volume of carbon dioxide released and absorbed equals the volume of oxygen absorbed

28
Q

What will increase oxygen uptake?

A

Increased breathing rate

Deeper breaths

29
Q

What is the structure of a fishes gaseous exchange system?

A

Gills covered by a bony plate- operculum
Gil consists of 2 rows of gill filaments- primary and secondary lamellae
Blood capillaries close to the surface of the secondary lamellae

30
Q

Why do fish have gills?

A

To absorb dissolved oxygen from the water.

31
Q

How does a fish have an effective exchange system?

A

Thin filaments are folded into secondary lamellae- large surface area.
Short diffusion distance- blood capillaries are close to the surface of secondary lamellae.
Countercurrent flow. - maintains steepest gradient

32
Q

Where does gaseous exchange take place in fish?

A

Secondary lamellae.

33
Q

What movements are coordinated in fish.

A

Buccal cavity and operculum. As water is pushed from buccal cavity the operculum moves outwards. This reduces pressure and water flows through the hills.

34
Q

What is the operculum?

A

A bony flap that covers and protects the gills.

35
Q

What are the two parts of an insect?

A

Thorax and abdomen.

36
Q

How does air enter an insects circulatory system?

A

Via a pore called a spiracle.

37
Q

How is air transported into the the insects body?

A

Through a system of tubes called the tracheae

38
Q

What are the tracholes?

A

Smaller tubes which the tracheae divide into. Ends are open and filled with tracheal fluid.

39
Q

How does gaseous exchange occur in insects?

A

Between the air in the tracheole and the tracheal fluid. Or across the thin walls of the tracholes.

40
Q

Why can more oxygen be absorbed when insect is active?

A

When tissues are active the tracheal fluid can be withdraw into the body fluid to increase the surface area of the tracheole wall exposed to air.

41
Q

How can some insects increase the volume of their thorax?

A

The tracheal system has flexible walls which can expand and contract.
Fying insects wings can alter the volume of thorax.
Locusts can alter the volume of abdomen with specialised breathing movements coordinatied with opening and closing valves in the spiracles.

42
Q

Explain countercurrent flow?

A

Blood flows in opposite direction to water. Blood increases in O2 concentration as it goes along. However even when blood is highly saturated the fresh water will always have a higher O2 conc. This ensures there is always a conc gradient.

43
Q

What are the 3 structures of the airways?

A

Trachea, bronchi and bronchioles

44
Q

What do smaller bronchioles not have?

A

Cartilage

45
Q

What requirements do airways need to be efficient?

A

Flexible to allow movement
Large enough to allow sufficient air the flow
Supported to prevent collapse when air pressure is low.

46
Q

When may the smooth muscle need to contract?

A

If there is harmful substances in the air. It is an involuntary act may be a result of an allergic reaction. Overreaction of this is asthma.

47
Q

What is a tissue?

A

A group of similar cells working together to carry out a specific function.

48
Q

What may cause airways to collapse?

A

Low pressure during inspiration.

49
Q

How do the cilia cells and goblet cells work to keep lungs healthy?

A

Goblet cells release mucus to trap pathogens.

Cilia cells waft mucus to the top of the airway to be swallowed

50
Q

Factors that affect vital capacity?

A

Age
Gender
Activity levels
Size of person (height)

51
Q

Precautions that should be taken before using a spirometer?

A

Mouthpiece should be sterilised
Subject should be healthy- free from asthma
No air leaks in apparatus
Water chamber must not me overfilled