Gas Exchange Flashcards
Respiration
A chemical reaction that releases energy from organic molecules and transfers it to ATP
Gas exchange
A consequence of respiration/ photosynthesis
Ventilation
Forcing water or air in or out so that a diffusion gradient is maintained
(In animals)
Gas exchange in single cell organisms like bacteria and algae
Via diffusion
As they are small so have a large SA:V
Gas exchange in insects
Air enters through spiracles in the abdomen and thorax which open and close according to the insects needs
Coverings ensure an unidirectional flow of air
Spiracles open to trachea that branch into tracheoles that are kept open by rings of chitin
The walls of the tracheoles are very thin and pass close to the muscle fibres or enter cells which allows for. Avery short diffusion pathway
Diffusion of O2 in the gaseous phase is a lot quicker than if the O2 were dissolved in water
Abdominal pumping
During ventilation art rest the muscles contract drawing air in through spiracles
To maintain a concentration gradient when the insect is active the air is expired through different spiracles to those of which it entered through
Maximising SA
- gas exchange in insects
When at rest the tracheoles are filled with fluid. When active this water moves into the muscle cells via osmosis inc the SA in the thracheole this is bc. The muscle cells respire anerobically and therefore decrease the W.P. Allowing a concentration gradient for the water to move int the cell via osmosis
Therefore there is more space for more air to be drawn in
How is CO2 removed in insects
It diffuse into the blood and out through the cuticle
However some does escape through spiracles
How is water loss dec in insects
Small SA:V
Waterproof layer and right chitin exoskeleton
Spiracles close
O2 in water
1% in water- 20% in air Not very stable Slower diffusion More dense so harder to move Nit enough O2 to support endothermy
Best O2 content in water
Water is
Cold- more O2 can dissolve
Clean- no bacteria respiring
Turbulent- maintained conc gradient
Gas exchange in fish
Water passes over flat plates called filaments in the gills
On top of the surface of these filaments are projections called lamellae that increase the SA
There is a short diffusion pathway as only membrane between blood and water
There is a counter current flow
Counter current flow
Maintains the diffusion gradient by inc the opportunity for O2 to diffuse and avoiding equilibrium
Gas exchange in mammals
- anatomy
Nasal cavity Epiglottis Trachea Bronchus- w/ rings of cartilage Lung ( pleural membrane - 1covers ribs, 1 covers lung w/ pleural space between the two ) Bronchioles- w/ rings of cartilage Terminal bronchioles - smooth muscle Alveoli
Where does Asthma occur
Bronchioles
What can trigger the allergic reaction ( asthma )
Dust
Pollution
Pollen
Exercise
Asthma cause the bronchioles to have
More mucus and thicker muscle
The alveoli is made up of
This cells - squamous epithelium ( alveolar epithelium )
tissue that lines bronchi and bronchiole is made up of
- what does it do
Ciliates columnar epithelium
- stops dust and bacteria penetrating the lungs
Rate of diffusion is quick as there is a large SA for it due to
Capillary networks surrounding millions of air sacs called alveoli
Alveoli have elastic tissue between them it separate them
Diffusion of gasses in mammals
O2 dissolves in the film of water on the surface of the squamous epithelium wall
It diffuses across the epithelial cells and the across the endothelial cells of the capillaries into the blood plasma.
The O2 diffuses into red blood cells and combines with haemoglobin to form oxyhemoglobin
CO2 diffuses vies Versa
Advantage and disadvantage of narrow capillaries
Passage of blood through lungs is slow
But slow passage allows Time for O2 to combine with haemoglobin and for CO2 to leave the solution
Not all air inspired reaches alveoli as…
Some stays in dead air space
Eg. Bronchi and trachea
When pressure of lungs < atmospheric pressure then …
Air in
When pressure of lungs > atmospheric pressure then …
Air out
What happens to the intercostal muscle during inspiration and expiration
Inspiration- contract
Expiration - relax
What happens to the rib cage during inspiration and expiration
Inspiration- moves up and out
Expiration - moves down and in
What happens to the diaphragm during inspiration and expiration
Inspiration- the muscle contracts and it moves down/ flattens
Expiration- the muscle relaxes and it moves up/ curves
What’s happens to the volume and pressure of the thorax during inspiration and expiration
Inspiration- vol increases and pressure dec
Expiration- vol dec and pressure increases
Tidal volume
Volume of air taken in/ given out during normal rhythmic breathing
Inspiratory reserve vol
The extra volume inhaled
Higher than tidal volume
Expiration reserve volume
The extra volume exhales
Below the tidal volume
Vital capacity
Total usable volume
Residual volume
The approximate air that remains in the lungs
Pulmonary ventilation =
Tidal vol x breathing rate
What is the ventilation of the thorax controlled by
Respiratory centre in the medulla
Exercise causes you to breathe…
Deeper and faster
Nicotine has what effects
Psychological and addictive effects
Nicotine cause harm to which places and why
Mimics neurotransmitter
Cardiovascular system - inc B.P and H.R so inc chance of CVD
Lungs - paralyses cilia so more bacteria in the lungs. Also constricts bronchioles so reduces air flow
How does CO harm you
Poisons RBC by combining with haemoglobin so O2 carrying capability dec by 10%
How does Tar harm you
Releases free radicals
- carcinogen
Can damage/ irritate lung tissue leading to bronchitis and emphysema
Cigarettes contain
Tar
Carbon monoxide
Nicotine
Emphysema
-chronic breathlessness
- caused by the breakdown of Thin walls of the alveoli
Alveoli walls become thicker and less elastic
Two types of Bronchitis are
Chronic and acute
Acute bronchitis
Lasts a few days and is associated with colds
Chronic bronchitis
Due to tar irritating bronchiole walls and triggering inflammation
Coughing
Usually contributes to development of emphysema
Other than bronchitis and emphysema smoking can cause _________
Pneumoconiosis
-Inc Chance of lung cancer
Fibrosis of the lungs
Permanent scarring of lunch tissue
Can develop an auto immune response to dust
Short breath and coughing
Worsens over time
Control of breathing after exercise
Exercise use starts
Muscles respire
More CO2 detected by chemoreceptors in carotid and aortic bodies
Impulse sent to respiratory centre in medulla
Impulse sent from medulla to intercostal muscle and diaphragm
Breath more often and deeper therefore pulmonary ventilation inc
