Gaseous Exchange Flashcards
Squamous epithelium (tissue) function:
Provides short diffusion distance
Ciliated epithelium function (tissue)
Cilia waft mucus along airway
Glandular tissue function (contain goblet cells)
Produces mucus
Cartilage tissue function
Supports airway
Smooth muscle tissue function
Constricts airway
Elastic tissue function
Recoils to dilate airway or help expel air from alveoli
Blood function (tissue)
Transport gases
Nervous tissue function
Carries messages to coordinate action
Connective tissue function
Holds other tissue together
Explain process of inspiration
- diaphragm contracts to move down and become flatter
- external intercostal muscles raise the ribs
- volume of chest cavity increases
- pressure in chest cavity drops below atmosphere pressure
- air is moved into lungs
Explain process of expiration
-diaphragm relaxes and is pushed up by displaced organs underneath
- external intercostal muscles relax and ribs fall
-internal intercostal muscles can contract - helps push air out
What’s tissue
Collection of cells to perform specific functions
Why do elastic fibres recoil after deformation
To dilate the airway and recoil in alveoli to reduce the size of alveoli during expiration
Explain process of respitory system
-gases pass by diffusion through thin walls of alveoli
-O2 passes from air in alveoli to the blood in capillaries
-blood supply maintain steep concentration gradient - blood system transports CO2 from tissue to lungs
-concentration of CO2 in blood is higher than in air of alveoli and CO2 diffuses into alveoli
-blood transports o2 away from lungs ensures o2 concentration in blood is lower than in alveoli
What’s a spiracle (insect tracheal system)
An opening in exoskeleton where air enters body of insect
They open and close to minimise water loss
Insect tracheal system
Air is transported into body from spiracle via trachea
Ends of tracheole are open and it’s filled with tracheal fluid
Gas exchange is direct from tracheal to tissue
Oxygen dissolves into tracheal fluid and diffuses into cells where needed
Tracheal fluid can be withdrawn into muscle tissue when oxygen needed quickly
things needed for efficient gas exchange in fish
gill filaments have large SA so increase diffusion
single layer capillary
Lots of capillaries so good blood supply so short diffusion pathway
Counter current as water and blood flow opposite direction
Features of specialised exchange surfaces
Large SA - achieved by folding
Thin barrier to reduce diffusion distance
Good blood supply - higher concentration gradient = faster diffusion
Diffusion distance :
Distance molecules need to travel to reach cells
