Gas exchange Flashcards
correlation co-effect
Scatter diagrams/scattergrams can be plotted and used to identify a relationship between two variables.
Features of a strong correlation
A strong correlation = large sample of data points, few outliers, most plots on/close to line of best fit.
why correlation cannot be sure there is an effect
Just because there is a correlation, does NOT mean that there is a causal link there could be other factors (gender, exercise, lifestyle and age).
Risk factors associated with lung disease
- smoking: 90% of people suffering from COPD are, or have been heavy smokers
- Air Pollution: Pollutant particles and gases for example sulfur dioxide increases the likelihood of COPD, especially in area of heavy instrusty
- Genetic makeup: some people are genetically more likely to get lung diseases, other less so this explains why some long term smokers never get lung disease while some die early.
- Infections- people who frequently get other chest infections also have a higher chance of COPD
- Occupation- people working with harmful chemicals, gases and dusts that can be inhaled have an increased risk of lung disease.
Risk factors of heart disease
- Smoking: 2 to 6 times more likely to get heart disease
- Carbon monoxide- combines with hemoglobin in the blood cells to form carboxyhemoglobin, reducing oxygen carrying ability of oxygen.
- Nicotine- stimulates the hormone adrenaline which increases heart rate and increases blood pressure
- Blood cherestol- essential component of membranes which carries the essential plasma
What is a risk factor
A risk factor is a factor that increases the probability of getting that disease.
Describe the relationship between the size of an organism, its SA:VOL ratio and gas exchange?
The larger an organism becomes, the smaller its surface area to volume (SA:VOL) ratio.
What are the features of a specialised gas exchange system?
Large surface area relative to the volume (large SA:VOL ratio).
Thin so the diffusion pathway is short and gas diffusion is rapid.
Selectively permeable so specific gases (carbon dioxide and oxygen) can diffuse easily.
Moist so gases can dissolve easily.
Maintain a steep concentration gradient using a method of ventilation.
Describe the structure of fish gills and how they are adapted for gaseous exchange.
- Gill arches
- Pairs of gill filaments
- Many parallel lamella - large SA:VOL ratio
- Lamella very thin - short diffusion distance
- Blood capillaries flow counter current to water
- Counter current flow maintains concentration gradient along the entire length of the lamella.
- Blood leaving the gills is almost fully saturated with oxygen / very low carbon dioxide.
Describe how fish ventilate their gills to maintain a steep concentration gradient.
Inspiration:
The mouth opens
The operculum closes the opening at the back of the pharynx.
The floor of the buccal cavity is lowered.
The volume inside the mouth cavity increases and so the pressure inside the cavity decreases.
This allows water to flow into the mouth.
Expiration:
The mouth closes.
The floor of the buccal cavity is raised.
The volume inside the mouth cavity decreases and so the pressure inside the cavity rises, forcing water back over the gills.
The operculum opens and water flows out.
Describe the gas exchange system in insects.
Spiracles are valved openings which helps limit water loss by evaporation.
Network of larger trachea and smaller tracheoles gives a large surface area.
Trachea are supported by rings of chitin to prevent collapse.
Insect’s abdomen move up and down to change pressure and ventilate the tracheal network (maintains concentration gradient for diffusion).
Tracheoles are ‘open ended’ and filled with fluid to help gases dissolve, speeding up gas exchange with the tissues.
Describe how oxygen and carbon dioxide concentrations in trachea change when insects ventilate.
Insect abdomen moves down.
Increase volume and decrease pressure.
Spiracles open and air moves into the tracheae.
Oxygen concentration increases and CO2 concentration decreases as gas exchange through diffusion occurs with the tissues.
Insect’s abdomen moves up.
Decreases volume and increase pressure.
Spiracles close.
Oxygen concentration decreases.
CO2 Concentration increases.
describe the gross structure of the human gas exchange system in terms of the alveoli, bronchioles, bronchi, trachea and lungs?
LUNGS - highly branched network of tubules ending in many air sacs called alveoli - large SA:VOL ratio for ‘gas exchange’.
TRACHEA - flexible airway supported by rings of cartilage to prevent collapse
BRONCHI - two tube divisions leading to the left and right lung. Lined with ciliated epithelium and mucus secreting cells to remove dirt particles.
BRONCHIOLES - smaller branches with smooth muscle walls. Lined with ciliated epithelium.
ALVEOLI - microscopic, elasticated, very thin air-sacs. Closely associated with pulmonary capillaries. Site of gas exchange.
describe the essential features of the alveolar epithelium as a surface over which gas exchange takes place?
Ventilated from the bronchioles - maintains the concentration gradient for gas exchange.
Thin, flat, one-cell thick alveolar walls - short diffusion distance so diffusion is rapid.
Alveolar epithelium (walls) are folded - increase SA.
Moist - helps gases dissolve (oxygen / carbon dioxide).
Associated with many capillaries - large SA:VOL ratio for gas exchange with the blood
Capillary cells are thin…
describe ventilation and the exchange of gases in the lungs including describing the mechanism of breathing, including the role of the diaphragm and the antagonistic interaction between the external and internal intercostal muscles in bringing about pressure changes in the thoracic cavity
Inspiration:
External intercostal muscle contract
Diaphragm contracts
Volume in thorax increases
Air pressure decreases
Air pressure outside greater than inside so air flows IN, inflating the lungs.
Expiration:
Internal intercostal muscle contract
Diaphragm relaxes
Elasticated alveoli recoil
Volume in thorax decreases
Air pressure increases
Air pressure in lungs greater than outside so air flows OUT, deflating the lungs.
