exchange and breathing Tracker test Flashcards
- Explain why some organisms need specialised exchange surfaces. (3)
They have a small surface area to volume ratio
High metabolic rate
Some cells are too deep in the body for rate of diffusion alone to supply the cells
. Describe the general features of an efficient exchange surface, for example root hair cells, alveoli and gills. (4)
A large surface area
Thin – short diffusion distance
Good blood supply (not root hair)
Steep concentration gradient
- Complete the table to describe the functions of cartilage, ciliated epithelium, goblet cells, smooth muscle and elastic fibres in the mammalian gaseous exchange system. (5)
Cartilage
Cartilage Provides support in the trachea and bronchi
Stops the trachea and bronchi collapsing when the pressure is low
- Complete the table to describe the functions of cartilage, ciliated epithelium, goblet cells, smooth muscle and elastic fibres in the mammalian gaseous exchange system. (5)
Ciliated epithelium
Waft mucus containing microorganisms to the back of the throat
- Complete the table to describe the functions of cartilage, ciliated epithelium, goblet cells, smooth muscle and elastic fibres in the mammalian gaseous exchange system. (5)
Goblet cells
Goblet cells Secrete mucus
Mucus traps dust and microorganisms
- Complete the table to describe the functions of cartilage, ciliated epithelium, goblet cells, smooth muscle and elastic fibres in the mammalian gaseous exchange system. (5)
Smooth muscle
Can contract to constrict the diameter of the bronchi and bronchioles
More air can flow into the alveoli
- Complete the table to describe the functions of cartilage, ciliated epithelium, goblet cells, smooth muscle and elastic fibres in the mammalian gaseous exchange system. (5)
Elastic fibres
Recoil to push air out of the lungs during exhalation
- Describe the mechanism of ventilation (inspiration and expiration) in mammals. (6)
During inspiration: (ORA for exhalation) External intercostal muscles contract Ribs move up and out Diaphragm contracts And flattens Volume of the thorax increases Pressure in the thorax falls below atmospheric pressure Air is drawn into the lungs
- Define the term tidal volume. State a typical value of tidal volume. (2)
The volume of air moved in and out of the lungs with each breath
Approximately 0.4 – 0.5dm3
- Define the term vital capacity. State a typical value of vital capacity. (2)
The maximum volume of air that can be breathed in, following the maximum possible exhalation.
Approximately 5dm3
- Describe how a spirometer works. (6)
The person puts a sterile mouthpiece in their mouth
Attaches a nose clip
As they inhale air is drawn out of the chamber
The lid moves down and a downwards line is drawn on the trace
As they exhale air is added to the chamber
The lid moves up and an upwards line is drawn on the trace
Soda lime absorbs the CO2
Therefore the volume of air in the chamber decreases
- Calculate the breathing rate and oxygen uptake from this spirometer trace. (3)
(SKIP)
Breathing rate = 10.5 breaths per minute
Oxygen uptake = 3.0 – 2.35 = 0.65
dm3min-1
- Describe the mechanism of ventilation and gas exchange in bony fish. (7)
Fish open mouth Lowers floor of buccal cavity Volume of buccal cavity increases Pressure becomes lower than the pressure in the water Water is sucked into the cavity Fish closes its mouth Pressure inside the buccal cavity increases Operculum opens Water moves backwards, over the gills Oxygen diffuses into the blood
- Describe the mechanism of ventilation and gas exchange in insects. (5)
If active spiracles open
Air diffuses through spiracles into the trachaea
Then into the tracheoles
Oxygen diffuses from the tracheoles into the cells
Carbon dioxide diffuses from the cells into the tracheoles
Muscle contraction can increase the volume of the thorax
If very active
- Describe how to dissect the gas exchange system of a bony fish. (2)
Push back the operculum
Remove the gills by cutting each gill arch
