Chapter 7 ~ Exhange Surfaces And Breathing

Question 1

Why are specialise exchange surfaces needed?

Answer 1

Because they provide a surface area to volume ratio, which is needed for diffusion
For metabolic activity
Single celled and multicellular organisms

Question 2

What are the features of an efficient exchange surface?

Answer 2

Increase surface area which is provided by the root hair cells
Thin layer provided by the alveoli
Good blood supply/ventilation to maintain gradient provided by the girls and alveolus

Question 3

Mammalian gas exchange system:
Explain the features of nasal cavity

Answer 3

Large surface area with good blood supply this warms the air to body temperature. It has a hairy lining which secretes mucus to trap dust and bacteria. It has a moist surface which increases the humidity of incoming air which reduces evaporation from exchange services.

Question 4

Mamalian gas exchange system:
What is the function and structure of a trachea?

Answer 4

It is a wide tube, supported by incomplete ring of strong fixable cartilage which provides support. The rings are incomplete so that food can move easily. It is lined with ciliated epithelium with goblet cells between and below the epithelial cells. The goblet cells to create mucus and the cilia beat and move the mucus

Question 5

Mammalian gas exchange system:
Explain the function and structure of bronchus and bronchioles

Answer 5

The trachea splits to form two bronchi, which form bronchioles. the bronchioles contain cartilage for structural support. The smaller bronchioles have no cartilage rings, and the walls of the bronchi contains smooth muscles. When the small smooth muscles contract, the bronchi constrict when it relaxes the bronchi dilate.

Question 6

** mammalian gas exchange system:**
Describe the structure and function of alveoli

Answer 6

Alveoli are the main gas exchange surfaces of the body.
It has a large surface area, Good blood supply provided by lots of capillaries surrounding the alveolus Its one cell thick which provides a short diffusion distance -
There are moist surfaces which dissolve gases and facilitates diffusion.
Made up of thin flat cells

Question 7

What are the two ways of ventilate from the lungs?

Answer 7

Inspiration and expiration

Question 8

Explain the process of inspiration

Answer 8

The external intercostal muscles contract and the internal intercostal muscles relax.
The rib cage moves in and out and the diaphragm muscles contract flatten and move down.
The volume of the thorax increases .
The pressure in the thorax decreases and becomes lower than atmospheric pressure .
Air flows into the lungs and down the pressure.

Question 9

Explain the process of expiration

Answer 9

The external intercostal muscles relax and the internal intercostal muscles contract.
The rib cage moves down and inwards.
The diaphragm muscles relaxes and moves up.
The volume of the thorax decreases.
pressure in the thorax increases and becomes higher than atmospheric pressure.
Air flows out of the lungs down a pressure gradient

Question 10

What are ways to measure the capacity of the lungs with explanation?

Answer 10

A peak flow meter measures, the rate at which air can be exhaled from the lungs
A vitalograph is a sophisticated version of the peak flow meter
A spirometer measures the volume of air inhaled and exhaled

Question 11

Explain the definition of tidal volume

Answer 11

It is the volume of air in each breath

Question 12

Explain the definition of vital capacity

Answer 12

It is the maximum volume of air a person can expel from lungs after maximum inhalation

Question 13

What is oxygen uptake / consumption

Answer 13

Volume of oxygen used up by body

Question 14

What is the breathing rate?

Answer 14

Number of breath taken per minute

Question 15

Process of ventilation in fish

Answer 15

1.the fish opens its mouth, lowering the floor of the buccal cavity. This increases the volume of buccal cavity which lowers the pressure in the buccal cavity
2. As pressure in the buccal cavity is lower than outside pressure, water flows up.
3. The fish closes its mouth raising the floor of the buccal cavity. Volume inside buccal cavity decreases,pressure increases and water is forced out across gill filaments
4. The pressure now builds up in cavity which forces that are to open and water out.

Question 16

Explain, expiration in fish

Answer 16

The mouth opens. The floor of the mouth is lowered, this increases volume of buccal cavity. Pressure decreases und water moves into buccal cavity. Opercular value closes and opercular cavity expands. The pressure lowers and floor of buccal cavity moves up increasing pressure so water moves out

Question 17

Explain, inspiration in fish

Answer 17

The mouth closes, the operculum opens and the sides of the opercular cavity move inwards. All of these actions increase the pressure in the opercular cavity and force water over the gills and out of the operculum. The floor of the buccal cavity is steadily moved up, maintaining a flow of water over the gills.

Question 18

How does gas exchange take place in insects?

Answer 18

In the thorax and abdomen of insects, there are small openings known as spiracles air enters and leaves the system through the spiracles, but water is also lost. The spiracles sphinicors are kept closed as much as possible to minimise water loss.

Question 19

Explain gas exchange of insects

Answer 19

Waterproof waxy cuticles which reduce evaporation
Thin hairs
Spiracles where air enters and leaves, this is opened and closed by sphincters
tracheae lined by spirals of hint in which is impermeable to gases

Question 20

Explain how tracheal fluid buildup in insects

Answer 20

The end of the trachioles are filled with water, the muscle cells which are around the tracheal respire and carry out an aerobic respiration. This produces lactate. This lowers the water potential and water moves from the tracheal into the cell via osmosis. This decreases the volume of liquid in the tragal, causing more air from the atmosphere to move in.

Question 21

What are ways, insects control water loss?

Answer 21

The closest very close using muscles/sphinicters
They have waterproof, waxy cuticles, which were reduces evaporation
They have thin hairs which also reduce evaporation

Question 22

Explain the countercurrent system of gas exchange in fish

Answer 22

Blood in the capillaries flow in the opposite direction to the water to maintain the concentration gradient of oxygen in the blood
Oxygen concentration in the water is higher than in blood so lots of water flow in

Question 23

What is the function of cartilage?

Answer 23

It’s strength and flexibility provides support and prevent the airways from collapsing when pressure drops during inhalation

Question 24

What do globlet cells do?

Answer 24

They secrete mucus which which traps dust and microorganisms to prevent infection

Question 25

Explain smooth muscle

Answer 25

They control and relax to expand a narrow airways

Question 26

Explain elastic fibre

Answer 26

They stretch when we breathe in and recoil when we breathe out

Question 27

Explain cilia

Answer 27

Beat to move mucus up towards the throat when when it swallowed and destroyed by stomach acid

Question 28

Explain ciliated epithelium

Answer 28

It is at tissue which contains hair like projections called cilia which help move particles out of the body