Respiratory systems Flashcards
What are the physical laws applied to respiration and examples?
Fick’s law (e.g. tracheole, amphibian skin, alveoli)=Rate of diffusion ∝ surface area × difference in concentration gradient / thickness of membrane.
Boyles law (e.g. buccal breathing, mammalian diaphragm)=States that a gas’s pressure and volume are inversely proportional
What is partial pressure?
What is atmospheric pressure at sea level?
What is the partial pressure of oxygen?
What is the partial pressure of CO2?
*pressure a specific gas would exert in isolation in the same volume
*760mm Hg (millimetres of mercury)
*21% (in air) of 760 =160 mmHg
*4% of 760=30.4mm Hg
What does movement of gas along the lung surface depend on, name the laws?
Which diffuses across the lung surface quicker, oxygen or carbon dioxide?
*Its partial pressure (Henry’s law)
*Its solubility and weight (Graham’s law)
CO2 is 22 x the solubility of O2 even though it is heavier (lighter molecules move faster)
O2 is not very soluble so how does it move around the body?
What do invertebrates have instead?
Haemoglobin in red blood cells for O2 transport
* 4 sub-units so can bind 4 X O2 binding heme molecules
- Haemocyanin in invertebrates can only bind 1 X O2
How many red blood cells do humans have?
- 250 million haemoglobin per RBC (25 trillion RBC)
What happens when the curve in an oxygen dissociation curve shifts to the left?
It has a higher affinity of oxygen
Explain what can affect the affinity of oxygen?
*When the curve is shifted to the left, this shows a higher affinity for oxygen which means lower CO2, higher pH and lower temperature.
*When the curve shifts to the right this shows a lower affinity for oxygen which means an increase in partial pressure of carbon dioxide, a decrease in the pH and an increase in temperature
pH= Bohr effect
What happens when CO2 dissolves in the blood?
It dissolves into the blood and is hydrated into bicarbonate.
Its slow in the blood but rapid in red blood cell carbonic anhydrase= forces the reaction to the right (amplifies Bohr effect)
In the lungs the reverse occurs driving the hydration reaction to the left
Arthropod respiration: insects
What do they use to respire?
How do they prevent water loss?
Spiracles around body to allow gas exchange pair per body segment in thorax & abdomen
However they need to prevent water loss:
-Guard hairs create air pocket to reduce air flow and decrease gradient. They can also close their spiracles via muscular contraction.
Taenidia (allows stretch)=They prevent the collapse of the trachea if the pressure within is reduced.
Insects take in Oxygen and expel Carbon Dioxide using the tracheae which branch out into tracheoles.
Trachaeole cells have a moist interface which facilitates the diffusion of the gases into those tubes to the fluid of the body tissue
What are the other adaptations of respiration in larger insects?
What is oxygen intake constrained to?
*Air sacs in dry conditions for oxygen storage to conserve water
“Discontinuous breath”
*Air sacs underwater for oxygen storage and keep out water
Not connected to circulatory system
-Oxygen intake constrained by rate of diffusion
-Targeted oxygen delivery constrained by open circulatory system.
Arthropod: amphibian respiration
arthropod=no lungs
amphibian= lungs with buccal pumping
What do Type II alveoli cells secrete and why?
pulmonary surfactant a fluid that will increase the rate of diffusion and prevent it from sticking to itself.
Describe how our lungs allow us to breath
When you inhale:
the intercostal muscles contract, pulling the ribcage upwards and outwards
the diaphragm contracts, pulling downwards, volume of the thorax increases and the pressure inside decreases
air is drawn into the lungs down a pressure gradient.
When you exhale:
the intercostal muscles relax pulling the ribcage downwards and inwards, the diaphragm relaxes, doming upwards,
volume of the thorax decreases and the pressure inside increases
air is pushed out of the lungs.
Do we use the whole capacity of lungs why?
Why don’t we have a maximum breath rate all the time?
No we always have a residual volume of air because otherwise our lungs would stick together costing us a lot of energy to unstick as well there being a lot of rigid structures such as the bronchioles that will not deflate.
There is a cost to breathing more due to muscle contraction in expanding the ribcage which is energetically expensive and more water loss.
Why do fish have a different respiratory system to mammals?
What is the order?
*water is more viscous than air and there is a lower concentration of oxygen in the water than there is in air.
They have a countercurrent system to maximise oxygen uptake
*Mouth opens –>buccal cavity –> over gills (lamellae)–>opercular cavity–> operculum open= air pushed out
A decrease in volume opens the operculum to force air out.
