3.1.2 Transport In Animals Flashcards
what are the similarities between circulatory systems of mammals and fish?
- both are closed systems
- both have a heart
- both carry oxygen using haemoglobin
- both have arteries/veins/capillaries
what are the differences between circulatory systems of a mammal and a fish?
- fish have single circulation and mammal has double
- blood pressure is lower in fish
- fish is less efficient at supplying oxygen to tissues
- fish only has 2 chambers in heart
what is the function of arteries are how are they adapted?
- carries blood away from heart under high pressure
- elastic layer: allows it to stretch and recoil
- collagen: provides support
- smooth muscle: provides strength to withstand the pressure
what is the function of veins and how are they adapted?
- carries blood back into the heart
- thin elastic layer: no stretch and recoil
- valves: prevent backflow of blood
- collagen: more than arteries for more support, carry large volumes of blood
what is the function of capillaries and how are they adapted?
- allow substances to diffuse between blood and tissue fluid
- walls are one cell thick: small diffusion distance
- small: forms network needed to exchange substances
what’s diastole?
- atria and ventricles both relax
- blood flows through AV valves
- blood enters and fills atria and ventricles passively
what’s atrial systole?
- atria contract
- pressure in atria increases
- blood flows through AV valves into ventricles
- ventricles fill and volume increases
- pressure in arteries is low
what’s ventricular systole?
- ventricles contract
- volume of ventricles decreases
- AV valves close
- SL valves open
- blood flows into aorta and pulmonary arteries
what are the steps in the cardiac cycle?
- diastole
- atrial systole
- ventricular systole
how is the action of the heart initiated and coordinated?
- SAN creates wave of excitation
- atrio ventricular node picks up electrical activity from SAN
- wave spreads over atrial wall which causes atria contract
- contraction is synchronised
- there is a delay caused by the AVN
- ensures blood has entered ventricles
- waves spread down the septum
- goes along bundle of his
- bundle of his conducts waves to apex
- purkyne fibres in walls of ventricles
- ventricles contract at the same time
how are hydrogencarbonate ions formed?
- CO2 diffuses from cells into red blood cells
- CO2 binds with water
- Enzyme carbonic anhydrase is used to form carbonic acid
- Carbonic acid dissociates into H+ and hydrogencarbonate ions
- Cl- ions diffuse in to balance out the charge (chloride shift)
how is the H+ reduced in the RBC after H2CO3 dissociates?
- oxyhaemoglobin (HbO3) dissociates into Hb and O2
- Hb acts as a buffer and binds to the H+ ions to keep pH constant —> forms haemoglibinic acid
- more CO2 leads to more dissociation of HbO3
describe why the Bohr shift takes place
- high conc of co2 means shape of Hb is altered (more H+ ions change tertiary structure)
- Hb’s affinity for o2 is reduced
- more dissociation of oxyhemoglobin so more o2 available for respiring tissues
- Hb acts as a buffer by forming haemoglobinic acid
- Hb binds to co2 to form carbaminohaemoglobin
what direction is the curve for fetal haemoglobin and why?
- to the left
- fetal haemoglobin has a higher affinity for oxygen than adult
- fetal Hb takes up o2 in lower partial pressure of o2
- placenta has low partial pressure of o2
- adult Hb dissociates in low o2 partial pressure
how do large plasma proteins result in oncotic pressure?
- cannot pass out through capillary wall but other solutes can
- imbalance of large plasma proteins between blood and tissue fluid results in oncotic pressure
why is there a downward trend in the ECG?
- volume of air in chamber decreases
- CO2 absorbed by soda lime
what does the standard deviation tell us?
- spread of data compared to the mean
- reduces affect of anomalies
