animal transport Flashcards
examples what of blood plasma carries?
glucose
amino acids
mineral ions
hormones
large blood proteins (albumin)
fibrinogen( blood clotting)
globulins (transport/immue system)
wbcs
what are the functions if the blood?
transport of: • O2 & CO2 to and from respiring cells •digested food from small intestine •nitrogenous waste • hormones •platelets •cells/ antibodies
- help maintain:
BODY TEMP
pH —> acts as a buffer
how does TISSUE FLUID form FROM PLASMA
• as blood flows from arterioles into capillaries
—> is still under pressure from surge of blood from each time the heart pumps
HYDROSTATIC PRESSURE
• at arterial end
hydrostatic»_space; oncotic pressure
= net flow of fluid out of the capillary
—> this fluid fills spaces between cells (containing oxygen/nutrients)
—> TISSUE FLUID
• at venous end
—> the hydrostatic pressure FALLS
—> the oncotic pressure had remained the same
SO
oncotic pressure > hydrostatic pressure
—> water moves back into capillaries by osmosis
= net flow of fluid (containing carbon dioxide/waste products) back into capillary by oncotic pressure
how is composition of tissue fluid different from plasma
Its the same apart from things that cant fit through fenestrations in capillaries
so:
- rbcs
- albumin
both STAY IN BLOOD
what is lymph
•some tissue fluid doesnt move hack into the capillaries
—> it drains into a system of blind ended tubes —> lymph capillaries
—> this is called LYMPH
what is lymph composed of?
similar to tissue fluid/plasma
- much less oxygen + nutrients
- fatty acids from intestine
how is lymph transported?
squeezing body muscles
—> lymph vessels have valves which stop the backflow of lymph
what do lymph nodes do
•lymphocytes build up in lymp nodes
—>produce antibodies into blood when necessary
• intercept bacteria/ other debris
how is oxygen transported?
haemoglobin in rbcs
4 oxygen binds to 1 haemoglobin
how do red blood cells carry oxygen?
POSITIVE COOPERATIVITY
•blood entering lungs capillaries have low o2 conc
—> creates a steep concentration gradient
between air in alveoli and blood
•o2 enters rbcs
—> binds to haemoglobin
•when one o2 binds to a haem group
—> molecule changes shape
—> making it easier for another o2 to bond to another haem group
• as the FREE o2 conc in an rbc remains LOW
—> steep conc gradient is maintained
—> until haemoglin in saturated with o2
what happens to oxyhaemoglobin when it reaches cell tissue
•conc of o2 is lower in cytoplasm of body cells , than in rbcs
—>o2 moves lit of rbc down conc gradient
• once first o2 is released
—> molecule changes shape
—>now easier to remove the rest of the o2
what does an oxygen dissociation curve show?
the affinity of haemoglobin for oxygen
—> a very small change in p(o2) causes sig diff to the saturation of haemoglobin
•this us because:
- once the first o2 molecule is attached
- Δshape of Hb causes other o2 to be added very rapidly
what is the shape of an oxygen dissociation curve?
it is sigmoidal
—> due to +ve cooperativity
•higher p(o2) in pulmonary capillaries
—> allows more o2 to bind with Hb
—> until the Hb becomes saturated so little addition binding of o2 occurs
= curve flattens out at this point
•with lower p(o2) in body cells
—> results in large amount of o2 being unloaded needed by cells
—> shown by steep curve
what is the Bohr effect?
change in oxygen affinity of haemoglobin at different p(CO2)
as p(co2) rises —> Hb gives up more o2 more easily
why is rhe bohr effect important?
•in more active cells
—> are respiring more
—> producing more co2
-these cells will jeed more o2 to maintain activity
—> so the increased co2 will cause more o2 to be unloaded by Hb
•in lungs p(co2) is low
—> allows o2 to bind more readily to Hb
why is the curve for foetal hamoglobin steepee than adult?
•fetus gets o2 only from mother
•oxygenated blood from mother
—> runs next to deoxygenated fetal blood
• if fetal Hb had same affinity for o2
—> no o2 would be transferred to fetal Hb
SO
a higher affinity is required
—> so fetal Hb can take o2 from adult Hb
3 ways co2 is transported?
• 5% dissolved in plasma
•10-20% as carbaminohaemoglobin
—> co2 combines with Hb
• 75-85% converted to HCO3-
—> in cytoplasm of rbcs
reversible reaction of co2 forming HCO3-
what is the chloride shift?
movement if bicarbonate ions (HCO3-) into red blood cells as H+ ions move out
—> to maintain electeochemical equilibrium
how does the chloride shift work
• co2 diffuses into rbcs
• co2 is converted to H2CO3
—>using carbonic anhydrase enzyme
•H₂CO₃ dissociates into HCO₃ - and H+ ions
•-ve hydrogen carbonate ions move out of rbcs by diffusion down conc gradient
—> -ve CHLORIDE ions move in
—> maintains electrochemical balance
why is co2 converted into hco3- ?
so rbcs can maintain a conc gradient for co2 to be removed from body cells
how is co2 released back into the lungs
• at lungs there is low conc of co2
• carbonic anhydrase
—> reversed reaction
—> h2co3 is converted back into co2 + h20
—>co2 diffuses back into lungs
how long does the cardiac cycle last
0.8s
what happens in diastole?
•the heart RELAXES
—> atria + ventricles fill will blood
—>pressure + volume of blood increases
-pressure in arteries is lower
