Chapter 7 Flashcards
Why can singled celled organism rely on diffusion to take in the oxygen needed and release the carbon dioxide
1) metabolic activity is low so oxygen demand and carbon dioxide production is low
2) the surface area to volume ratio is large
3) there is a small distance substances must travel
Why must multicellular organisms have specialised exchange surfaces?
1) they have billions of cells so metabolic activity is incredibly high thus so is oxygen demand and carbon dioxide production
2) the distance to inner cells is too far to diffuse
3) the surface area to volume ratio is small
How do you calculate surface area to volume ratio?
By dividing surface area by volume
What are the features of an efficient exchange surface?
1) a large surface area providing the area needed for exchange
2) a good blood supply/ ventilation system to help maintain a high concentration gradient
3) thin layers- so the diffusion pathway is short speeding up the process
Give an example of a cell/ organ with a good blood supply/ good ventilation system
The alveoli have a large capillary network with a good blood supply and are ventilated constantly as we breath
The gills have a capillary network with a good blood supply and are constantly ventilated as water passed over them
Give an example of a cell with a large surface area
A root hair cell had a long ‘hair’ like projection which gives it a larger surface area for absorption
Give an example of a organ with thin layers
The alveoli are made from a single layer of flat cells called alveolar which decrease the distance O2 and CO3 have to travel
What is cartilage?
Cartilage is in the walls of the trachea and bronchi, they are flexible and provide support to prevent collapse when pressure decreases during inhalation
What is the cilliated epithelium?
Beats mucus away from the alveoli to the throat where it is swallowed
What are goblet cells?
Goblet cells secrete mucus which traps microorganisms and dust stopping them reaching the alveoli
What is smooth muscle?
In the walls of the trachea , bronchi and bronchioles and allows diameter to be controlled by tensing and relaxing
What are elastic fibres?
In the walls of the trachea , bronchi and bronchioles they help exhalation by stretching as the lungs inflate and recoil to help push the air out while exhaling
Which components does the trachea and bronchi have?
The trachea had cartilage , cilliated epithelium, goblet cells , smooth muscle and elastic fibres
Which components do the bronchioles have?
Cilliated epithelium, smooth muscle and elastic fibres
Which components do the alveoli have?
Elastic fibres
Explain the process of inspiration and what type of process it is
1) the external intercostal muscles and the diaphragm contract causing the ribcage to move up and out and the diaphragm to flatten increasing the volume
2) lung pressure thus decreases causing air to flow into the lungs
This is an active process
Explain the process of expiration and what type of process it is
1) the external intercostal muscles and diaphragm relax causing the ribcage to move down and in and diaphragm curve decreasing the volume
2) lung pressure increases forcing air out
It is a passive process
What is forced expiration?
Forced expiration is when the internal intercostal muscles are contracted forcing air out
What is vital capacity?
Vital capacity is the maximum volume of air that can be breathed in or out
What is oxygen consumption
Oxygen consumption is the rate at which an organism uses up oxygen
Ventilation rate=
Ventilation rate= tidal volume X breathing rate
What is breathing rate?
Breathing rate is the number of breaths per minute
What is tidal volume?
Tidal volume is the volume of air in each resting breath
What is a spirometer
A spirometer has an oxygen filled chamber with a movable lid
The subject breathes through a tube causing the lid to move up and down
A pen is attached to the lid and writes on a rotating drum creating a spirometer trace
The soda lime in the tube absorbs the carbon dioxide
