Physiology 4: Respiration Flashcards
What does respiration require?
O2 and C6H12O6
What are the by products of respiration?
CO2 and H20
What are the issues that must be overcome in respiration?
O2 and glucose need to get to the cells
Co2 is toxic
Gases cross surface by diffusion only
Label the gas exchange formula (add photo)
R = rate of diffusion
ΔP = Diff in partial pressure
A = Surface area
T = Temp
S = solubility
D = distance
Mw = molecular weight
What are the 3 general components of respiratory systems?
- Specialised surface where gas exchange takes place → need to be wet
- Breathing mechanisms to bring fresh air / water to the surfaces
- In some organisms circulatory mechanisms for transporting gases
Describe the process of respiration in insects
- Air diffuses in through spiracles
- Enters tracheae
- These branch into tracheoles
Describe how insects use active ventilation
Trachea inflate and deflate to pump air through
Larger may also exhibit rhythmic body movements
Tidal ventilation via spiracles
Why do insects close their spiracles?
Prevents water loss
Prevents debris from entering
Why do insects have a high water loss potential?
Because they have a large SA:V
How do insects maintain water loss
Must balance between losing water and gaining O2
Hairs around spiracles =decrease the diff gradient of water mols
Evolved hard cuticle
Close spiracles when environ is dry → air sacs store air
In vertebrates, describe what happens to Hb O2 affinity at lower temps.
Higher O2 affinity
In vertebrates, describe what happens to Hb O2 affinity at higher temps.
Lower affinity
Describe the Bohr effect.
(ore acidic) lower pH = lower affinity so haemoglobin readily dissociates O2
Co2 reacts with H2O = carbonic acid
Co2 dissolved in water lowers pH
Anaerobic resp = lactic acid (lowers pH)
In vertebrates, describe what happens to Hb O2 affinity at higher pH.
Lower affinity
In vertebrates, describe what happens to Hb O2 affinity at lower pH.
Higher affinity
Foetal haemoglobin has a _____ _____ for O2 compared to adult
higher affinity
What are O2 levels like in water?
Low
Warmer saltier waters hold ____ O2
less oxygen → challenge for respiration
Describe the gill filaments
Large SA
Capillary network
Thin membrane
Why do fish pump water across their gills?
Ensures fresh water is moving across gills
→ Energetically costly
Describe the countercurrent flow.
- Blood flows in the opposite direction to water
- Blood is deoxygenated after visiting tissues
- O2 diffuses from water into blood
- Conc. gradient maintained across the whole surface
Describe how birds use their 2 breaths.
Crosscurrent flow of air and blood:
First inhalation movies into the posterior air sac → expand
First exhalation moves from air sacs into lungs → gas exchange occurs
Second inhalation moves from the lungs to the anterior air sacs
Second exhalation air moves from the anterior sacs out of the bird
Do birds use tidal ventilation?
No, unlike insects or humans, air is completely exchanged
Describe the features of a birds gas exchange system
High SA for gas exchange
Significantly thinner surfaces for gas exchange
Can breathe easily at high altitudes
- Lower oxygen partial pressure
Adapted for the high metabolic demands of flight
Describe mammals inhalation
Intercostal muscles contract
Diaphragm contracts
Pressure inside chest decreases
Air rushes in
Describe mammals exhalation
Intercostal muscles relax
Diaphragm relaxes
Pressure inside chest increases
Air forced out
What are 2 adaptations mammals have for ventilation?
Lungs inside body
- Decreases water loss
Alveoli
- Increase SA
- 1 cell thick (decreases diffusion distance)
Describe mammals ‘ventilated pool’
- Fresh air comes in and fills the alveoli
- Air is never completely exchanged in the lungs
- Blood flows in 1 direction past the alveoli
- Less efficient than birds bc the O2 conc of the air is high
Describe tidal ventilation in mammals
Air enters and leaves via the same path
Not all air is exchanged
O2 conc. inside lungs always lower than the conc. outside the lungs
How are marine mammals suited to aquatic life (in terms of respiration)?
- Store O2 in muscles
- High myoglobin conc.
- Store O2 in blood
- Higher Hb conc.
- More efficient at extracting O2
- Temporarily cut off circulation to some parts of body
