2 structure and functions in living organisms G (gas exchange in humans) Flashcards
main components of the breathing system:
- ribs
- intercostal muscles
- lungs
- diaphragm
- trachea
- bronchi
- bronchioles
- alveoli
- plural membranes
where is the gas exchange system located?
in the thorax (upper part of the body)
structure of the trachea:
- tube with connects the mouth and the nose to the bronchi in the lungs
- made of C-shaped rings which prevent the tube from collapsing into itself
- made with goblet and epithilial cells
structure of the ribs:
help to protect the organs in the thorax
structure of the intercostal muscles
between the ribs, help to connect the bones and are important in moving air in and out of the lungs
structure of the diaphragm:
- below the lungs, separating the organs of the thorax and the abdomen
- domed sheet of tissue and muscle is important in moving air into and out of the lungs
structure of the bronchi:
- when the trachea splits open it forms the bronchi
- these tubes lead to the lungs
- also surrounded by cartilage rings
structure of the bronchioles:
- when the bronchi divide or branch into smaller and smaller tubes
- carry air deep into the thorax
structure of the alveoli:
- at the end of each bronchiole
- site of gas exchange
structure of the pleural membranes:
- lungs are surrounded by these
- forms a double layer between the lungs and the thorax walls
- in between the membranes there is a thin layer of pleural fluid
- together they form an air tight seal and prevent the lungs from sticking to the thorax wall as they inflate and deflate
define ventilation:
the process of moving air into and out of the lungs, moving air relies on differences in air pressure between the lungs and the atmosphere
describe the process of inhalation:
- diaphragm contracts, moving down and flattening, intercostal muscles contract, moving ribcage up and out
- this causes the volume of the thorax to increase and air pressure in the thorax to fall
- air pressure in the thorax is now less than atmospheric pressure, causing air to move into the lungs
describe the process of exhalation:
- diaphragm relaxes, moving up and doming, intercostal muscles relax, moving rib cage down and in
- this causes the volume of the thorax to decrease and air pressure in the thorax to rise
- air pressure in the thorax is now more than atmospheric pressure
how are the alveoli adapted for gas exchange?
- lots of them- large surface area- increases the rate of diffusion
- lots of capillaries- high concentration gradient- increases rate of diffusion
- one cell thick- very short diffusion distance- faster diffusion
what is present in tobacco smoke?
carbon monoxide in tobacco smoke- permanently binds to haemoglobin- reduces the amount go oxygen in the blood
what effect do the chemicals in the tobacco smoke have on cilia?
- destroy and reduce the number of cilia
- increase mucus production
- mucus cannot be moved out of the airways quickly so builds up
- this causes smokers cough and increases the risk of infections
- bronchitis is a disease resulting from the build- up of infected mucus in the bronchi and bronchioles
what effect do the chemicals in the tobacco smoke have on alveoli?
- damages them
- alveoli walls freak down in places and fuse together forming larger, irregular air spaces
- decreases the surface area for gas exchange
- so less oxygen diffuses into the blood
- this disease is called emphysema
what does smoking increase your risk of?
- coronary heart disease
- lung cancer
Practical: The Effect of Exercise on Breathing:
- count the number o breaths someone takes in 30 seconds at rest
- ask them to jog or five minutes
- calculate the number of breaths in the first 30 seconds straight after exercise
- limewater to calculate the release of CO2- inhaled air stays colourless, exhaled air turns milky white
- control age, gender, fitness
