Exchange Surfaces And Breathing

Question 1

Why can large or multicellular organisms not use diffusion alone to absorb nutrients?

Answer 1

They have a greater metabolic activity and more demands which means more oxygen and other nutrients are needed,

Diffusion also occurs too slowly and doesn’t reach all the necessary cells,

This means they have specialised transport systems

Question 2

What is the equation for the surface area and circumference of a circle?

Answer 2

Area-π𝒓²

Circumference-2π𝒓

Question 3

What is the equation for the surface area and volume of a cuboid?

Answer 3

Surface area-2 (bh+bl+hl)

Volume of cuboid-hbl

Question 4

What are the three characteristics of a well adapted exchange surface?

Answer 4

Large surface area

Thin barriers for a short diffusion pathway

Concentration gradient is maintained by molecules being constantly supplied and removed

Question 5

What is the role of the alveoli?

Answer 5

They are tiny air sacs in the lungs that facilitate gaseous exchange. They transport oxygen into the bloodstream and take in carbon dioxide.

Question 6

How are the lungs adapted to their function?

Answer 6

-The alveoli provide a large surface area for gaseous exchange

-Surfactant prevents the alveoli from sticking together and allows gases to dissolve

-Permeable to oxygen and carbon dioxide as they can diffuse across the membrane

-Thin barriers reduce diffusion distance-alveolar and capillary walls are one cell thick

-Concentration gradient is maintained by blood flow and ventilation

Question 7

Explain the mechanisms of ventilation when inhaling

Answer 7

-The diaphragm contracts and moves down

-External intercostals contract which moves ribs up and out while the internals contract

-Volume of the chest increases

-Pressure in the lungs falls below atmospheric pressure to allow air to move in

Question 8

Explain the mechanics of ventilation when exhaling

Answer 8

-Diaphragm relaxes and moves up

-External intercostals relax which causes the ribs to move down and in while the internals contract

-Volume of the chest decreases

-Pressure in the lungs rises above atmospheric pressure to allow air to move out

Question 9

What muscle is used during forced exhalation?

Answer 9

Abdominals

Question 10

What tissues and cells make up a bronchiole?

Answer 10

Smooth muscle,

Ciliated epithelium,

Goblet cells,

Blood vessels,

Loose tissue with elastic fibres

Question 11

What tissues and cells make up a bronchus?

Answer 11

Cartilage,

Smooth muscle and elastic fibres,

Blood vessels,

Ciliated epithelium with goblet cells

Question 12

What is the role and shape of cartilage in the trachea?

Answer 12

C-shaped cartilage rings

Used to prevent collapse and bursting of the trachea during pressure changes,

Flexible to allow movement of the neck and expansion of the oesophagus when swallowing

Question 13

What is the role of cartilage in ventilation?

Answer 13

Used to keep the airways open and prevent them from being damaged by pressure changes or air flow

Question 14

What is the role of smooth muscle in ventilation?

Answer 14

It can contract or relax to open or close the airways and change airflow

Question 15

What is the role of elastic fibres in ventilation?

Answer 15

Allows the airways to stretch and recoil which helps prevent damage

Question 16

What is the role of goblet cells in ventilation?

Answer 16

They produce mucus which traps dust and microorganisms that have been inhaled to protect the alveoli

Question 17

What is the role of ciliated cells?

Answer 17

They line the airways and waft mucus towards the throat to be swallowed

Question 18

Define vital capacity and tidal volume

Answer 18

Vital capacity- The maximum volume of air that can be inhaled or exhaled in one breath

Tidal volume- The volume of air that is inhaled or exhaled in one breath at rest (around 15% of vital capacity)

Question 19

Define residual volume and how you can calculate total lung capacity

Answer 19

The volume of air left in the lungs after hardest possible exhale

Lung capacity can be calculated by
Vital capacity + residual volume

Question 20

Define oxygen uptake and breathing rate

Answer 20

Oxygen uptake- Rate of oxygen consumption (dm³/min)

Breathing rate- Number of breaths per unit of time

Question 21

What are the average vital capacities of males and females in normal and athletic conditions

Answer 21

Normal:
Male- 4.6 dm³
Female- 3.1 dm³

Athlete:
Male- 6.0 dm³
Female- 4.6 dm³

Question 22

What is the function of a peak flow meter?

Answer 22

Measures the rate at which air can be expelled and taken into the lungs (L/min)

Question 23

What is the function of vitalograpghs?

Answer 23

Advanced version of the peak flow meter that puts data onto a graph

Question 24

What is the function of a spirometer?

Answer 24

Measures volume of the lungs and can be used to check breathing patterns

Question 25

Explain how a spirometer produces a graph

Answer 25

When inhaling the spirometer chamber goes down, This causes a pen to go down of graph paper, This means when the trace goes down it represents inhalation And when it goes up it represents exhalation

Question 26

What are 4 precautions to take when setting up a spirometer

Answer 26

There is enough oxygen in the chamber, The mouthpiece is disinfected, The person wears a nose clip to ensure all air breathed out come from the chamber There is a counterbalance in place

Question 27

What chemical can be used to remove CO2 from a spirometer

Answer 27

Soda lime

Question 28

Why does a spirometer graph gradually drop and what does this allow us to do?

Answer 28

Soda lime absorbs CO2 in the spirometer, This reduces the total volume of gas in the chamber, Causing the graph to drop as more CO2 is absorbed, CO2 being absorbed tells us how much O2 is used up so we can calculate O2 usage

Question 29

How do you calculate oxygen uptake?

Answer 29

Measure the reduction in the chamber between two points, Calculate the time taken between these two points, Divide the reduction by the time then times by 60, Reduction in chamber -------------------------------- X 60 Time taken This gives oxygen consumption in dm³/min and the same value applies to carbon dioxide removed

Question 30

Define breathing rate and ventilation rate

Answer 30

Breathing rate- The number of breaths per minute Ventilation rate- The total volume of air inhaled in one minute

Question 31

What is the buccal cavity?

Answer 31

The mouth on a fish

Question 32

Explain the process of ventilation in a bony fish

Answer 32

The fish opens its mouth and lowers the floor of the buccal cavity, Volume of the buccal cavity increases which decreases pressure as water enters the mouth, The fish closes its mouth which raises the floor of the buccal cavity which decreases volume and increases pressure, This forces water out across the fill filament, The operculum is then forced open and water leaves the gills

Question 33

Explain the role of the operculum

Answer 33

It is a gill covering made of bone that is involved in the protection of the gills, It allows water pressure to build when the fish opens its mouth resulting in it being forced open when the mouth closes allowing water to flow through the gills

Question 34

Explain the key characteristics of the gills

Answer 34

The gill arch contains an artery which transports deoxygenated blood to the gill, The gill arch also contains vessels that carry oxygenated from the gill, The gill arch has primary lamellae attached to it and secondary lamellae line the top

Question 35

State and explain how the gills are adapted for gas exchange

Answer 35

Each gill is made of many primary lamellae which results in a large SA- this is helpful because a larger SA means there is more space for oxygen to diffuse onto, The primary lamellae are covered in secondary lamellae which further increases the SA- this means there is more space for oxygen to diffuse onto Secondary lamellae have a lot of capillaries and a thin layer of cells- this means oxygen can diffuse across quickly and then transported away quickly due to the high blood supply The arch has an artery and multiple vessels to carry oxygenated and deoxygenated blood- this means that oxygen can be transported in larger quantities due to the larger vessel size

Question 36

Explain the counter current system

Answer 36

Blood flows through the gills in the opposite direction to the water flow which maintains a steep concentration gradient, This results in the net movement of oxygen by diffusion is always into the blood

Question 37

What are the steps involved in a fish dissection?

Answer 37

1)Ensure you are wearing an apron and gloves as it can be messy 2)Place your chosen fish in a dissection tray or cutting board 3)Push back the operculum and use scissors to carefully remove the gills. Cut each gill arch through the bone at the top and bottom 4)Look closely to identify the fill filaments (primary lamellae) and then draw and label

Question 38

Explain how gas exchange occurs in an insect

Answer 38

Air moves in the spiracles and then into tiny air filled tracheae, The tracheae branch off into smaller tracheoles which have thin permeable walls, Oxygen goes from the air, to the tracheae, to the tracheoles, to the cells, Carbon dioxide diffuses the opposite way, Insects use rhythmic abdominal movements and wing movements when flying to move air in and out of the spiracles

Question 39

How are insects adapted for gas exchange?

Answer 39

The tracheae and tracheoles give a large surface area for more diffusion, The tracheoles are lines with singular cells to minimise diffusion distance while also providing a larger SA

Question 40

What can an insect do to further increase SA?

Answer 40

They can withdraw a fluid from within the tracheoles when active