3.1 Exchange And Trasnport Flashcards
What happens to a animals exchange surface as it gets larger?
- their cells are too far from the exchange and membranes or surfaces for substances to simplify diffuse across
- so they need special exchanges surfaces (eg. Lungs )
What can single celled organisms do?
- they can exchange across outer surfaces
- due to a large SA:V
What special about larger organisms when exchanging substances?
- as they are more active they need special ways as they demand more ( eg. 02 )
- travel long distances
What is an exchange surface?
An exchange surface is a specialised area that is adapted to make it easier for molecules to cross from one die to another
- eg alveoli and root hair cells
What makes an exchange system efficient ?
- a large SA, this allows more movement of particles across the cell
- a thin layer, this allows for a short diffusion distance
- maintain a good concentration gradient, as this allows for a good blood supply and ventilation
What is the passage of airway through the gas exchange system?
- trachea, which divides into two
-bronchi, which further divides - bronchioles, which terminate into millions of alveoli
Explain how the alveoli create a surface for efficient gaseous exchange
- wall is one cell thick for shorter
diffusion distance - squamous epithelium provide
short diffusion distance
3.elastic in walls can recoil to expel air which helps
ventilation - ventilation maintains concentration
gradient
5.large number of alveoli provide large
surface area
6.small size alveoli provide larger
surface area to volume ratio
Why does air move into and out of the lungs?
differences in volume and pressure
Ventilation
Movement of air in and out of the lungs
Function of Trachea ( what does it contain )
allows air to reach lungs. contains c-shaped rings of cartilage, smooth muscle, elastic fibres, goblet cells, ciliated epithelium.
function of Cartilage
strong connective tissue that supports the trachea and bronchi. it is found in rings (so when the pressure drops the trachea doesn’t collapse)
Ciliated epithelium. what do they prevent
Cilia on epithelium that line the airways can beat/waft mucus up the airways away from the alveoli.
The mucus traps bacteria or pathogens, which prevents lung infections.
Goblet cells
Unicellular exocrine glands that secrete mucus. they line the trachea, bronchi and bronchioles.
function of elastic fibres?
They are found in the trachea, bronchi and bronchioles. Elasticity is needed for the lungs to recoil to push air out
function of smooth muscle?
also found in the trachea, bronchi and bronchioles. It controls the diameter of the airways as the muscle can contract and relax.
Contraction narrows the lumen, restricting air flow. this is important if harmful substances are present.
It can also relax, to make tubes wider during exercise. This means there is less resistance to airflow so air can enter lungs more easily.
Bronchus
similar to trachea but have a smaller diameter and thin walls. contain complete rings of cartilage, smooth muscle, elastic fibres, goblet cells and ciliated epithelium
Bronchioles
Airways in the lungs that lead from the bronchi to the alveoli. Airways in the lungs that lead from the bronchi to the alveoli.
what do large bronchioles contain
no cartilage as more self-supporting, they contain elastic and muscle fibres so can adjust the diameter to increase the airflow. do contain ciliatated epithelium
what do smaller bronchioles contain?
smooth muscle and elastic fibres, no goblet cells and no cilia on epithelium
what do smallest bronchioles contain
elastic fibres, no smooth muscle, no goblet or cilia
Alveoli
tiny sacs of lung tissue specialized for the movement of gases between air and blood
Elastic recoil
tendency for the lungs to reduce in volume after being stretched or expanded
Inspiration
The process of actively contracting the inspiratory muscles to move air into the body
Thorax
The body region between the head and the abdomen