blood and oxygen transport Flashcards
boyle’s law
pressure inversely related to vol
inspiration
increase vol through diaphragm and external intercostals contract
decrease pressure in alveoli
air fills lungs
gases and pressure
move across membrane by diffusion
down pressure gradient
pressure higher in alveoli than blood
- oxygen cascade
dalton’s law
total pressure of a mixture is equal to the sum of the partial pressure if the individual gases in a mixture
partial pressure = % conc x total pressure of mixture
total pressure = 760 mm Hg or 1 ATM
atmospheric air
oxygen = 20.93%
co2 = 0.03%
nitrogen 79.04%
henry’s law
when mixture of a gas in contact with a liquid each gas dissolves in liquid in proportion to it’s partial pressure and solubility until equilibrium is achieved and gas partial pressure equal in both locations
= conc of gas dissolved in liquid proportional to its partial pressure and solubility
solubility constant
pressure gradient critical
fick’s law
rate of gas transfer proportional to tissue area, diffusion coefficient of gas and difference in partial pressure of gas on two side of tissue and inversely proportional to thickness
capillaries
single cell layer (thin)
skeletal muscles have dense capillary networks 200-300/mm^2
- large surface area
slower blood flow in capillary bed
- more time for exchange of gases
oxygen cascade (transport) and gas exchange
air enters lungs due to changes in total pressure
o2 enter system and then transported to be used in mitochondria / cells/ tissues/ organs
blood smaples
capillary
- fingertip
- ear
venous
- venipuncture
- cannula
needed for blood collection
disinfectant
sterile swabs
sterile gloves
safety-lancet
appropriate sample containers
plasters
waste container
sample container
capillaries/ vessels should be kept horizontal/ slightly inclined
invert after filled with blood
blood components
plasma
- 91.5% water
- 7% protein
- 1.5% other
buffy coat
- thin layer
red blood cells
- haematocrit
-> female 37-47 %
-> male 42-52%
oxygen transport
oxygen dissolved in plasma (%)
- ~3 mol of o2 per litre of blood
- dissolved o2 establishes po2 of blood which:
-> regulates bretahing
-> determines loading of haemoglobin
o2 combined with haemoglobin (~99%)
- o2 moves into RBC via diffusion
- binds with haemoglobin
- moves to tissue
- unbind and diffuse into tissue for use
red blood cell and haemoglobin
red blood cell
- ~8 um
- biconcave shape increases SA and thus rate of diffusion
haemoglobin
- 4 iron molecules per
- 1 molecule per iron group
- high affinity for o2 (degree to which a substance combines with another)
haemoglobin affinity factors
acidity (acidosis)
- acidity increases/ pH decreases
- affinity of Hb decrease
- more O2 delivered to acidic sites
pCo2
- rises during exercise
- affinity of Hb decrease
- harder tissue working more o2 released
2,3- biphosphoglyceric acid
- BPG formed during glycolysis
- helps to unload o2 by binding with Hb
temperature
- increases, higher unload
- affinity Hb decreases
- more o2 delivered to warmed muscle
- during hypothermia more o2 remains bound
myoglobin
iron-containing globular protein is skeletal and cardiac muscle
1 iron atom
even higher affinity than Hb
- even at low o2
transfer o2 from cell membrane to mitochondria/muscles
cytochrome C oxidase
o2 binds to Hb a3 group
higher affinity than myoglobin
o2 then the final electron acceptor in the muscle
importance of RBC
increased o2 demand = increased unloading
at same time RBCs release ATP and NO
O2 sensors increase blood flow
- stimulates vasodilation
- inhibits vasoconstriction
CO2 transport methods
dissolved CO2 (~7%)
carbamino compounds (~23%)
- carbamino- haemoglobin
bicarbonate ions (~70%)
- in plasma as HCO3-
training and O2 transport
legal advantage
- training elicits hypoxaemia (low 02 levels)
- changes in o2 levels cause kidneys to secrete EPO (erythroprotein) hormone
- stimulates RBC production in marrow of long bones
- increase RBC mass and thus haemoglobin
- increase 02 carry capacity
illegal advantage
- blood doping
- withdraw some blood and store in fridge
- training recovers RBC mass
- injection of own blood increase RBC
EPO injections
EPO is a hormone produced by the kidney
regulates the body’s production of RBCs
athletes using EPO do so to encourage their bodies to produce higher than normal amounts of RBCs to enhance performance
decreased O2 carrying capacity - hypobaric enviro
- conc of gases in mixture stays the same
- reduction in total pressure decreases the partial pressure of O2
- less molecules
- diff latitude is not conc of gases but total pressure
decreased O2 carrying capacity - anemia
- reduces RBCs
- reduces iron and thus O2 carrying capacity
