Transport in animals 3.2 Flashcards
the need for transport systems in multicellular animals
- larger animals have a smaller surface area to volume ratio
- have a longer diffusion distance so they cannot rely on diffusion aloneas it will be too slow the high metabolic rates of animals
single circulatory system
the blood flows through the heart once for each circuit in the body
double circulatory system
blood flows through the heart twice for each circuit in the body
pulmonary circulation
-carries blood to the lungs to pick up oxygen
systematic circulation
carries the oxygen and nutrients around the body to the tissues,
why is having a double cirulatory system benefical for mammals
-Because blood pressure is reduced when being taken to the lungs to avoid damaging delicate capilaries but it would be too slow for the rest of the body so it allows blood to be carried at a high pressure around the rest of the body
closed circulatory system
blood remains within the vessels
disadvantages of open circulatory system
- blood pressure is low and blood flow is slow
- circulation of blood may be affected by body movements or lack of body movements
open circulatory system
blood is not held within the blood vessels
structure of the arteries
- thick walls to withstand high pressure
- small lumen to maintain high pressure
- inner layer(tunica intima) consist of a relatively thick layer of elastic tissue to allow the walls to stretch and recoil maintaining blood pressure
- middle layer(tunica media) consists of a thick layer of smooth muscle which controls the diameter of the artery
- outer layer(tunica adventitia) consists of collagen fibres to provide strength to withstand high pressure
function of the arterioles
distribute the blood from an artery to a capillaries
structure of the arterioles
- walls consists of a layer of smooth muscle which constrict the diameter of the arterioles
structure of the capillaries
- thin walls one endothelium cell thick
- red blood cells squeeze against the walls of the capillary reducing the diffusion distance
function of the venules
collect blood from the capillaries to the veins
structure of the venules
- Has elastic tissue and collagen
structure of the veins
- thin walls
- large lumen to maximise blood flow
- contains values to stop backflow
describe the cardiac cycle
- Blood enters the atria via the vena cava and pulmonary vein
-At atrial systole the atria contracts which decreases their volume and increase their pressure pushing blood into the ventricles through the atrioventricular values - the atria relaxes(diastole). The ventricular systole occurs decreasing their volume and their pressure becomes higher than in the artful so the atrioventricular values shut and the semi-lunar values open
- blood is forced out into the pulmonary artery and aorta
- when both atria and ventricles are in diastole the semi-lunar value close
How is tissue fluid formed ?
- the blood at the arteriole end of then capilary is under a higher blood pressure than at the venule end
- the hydrostatic pressure is higher than the oncotic pressure at the ateriol end
- water,dissolved solutes,glucose and amino acids are forced out of the capilaries through fenestrations
- large proteins and red blood cells stay in the blood and reduce the water potential
- the oncotic pressure is higher than the hydrostatic pressure at the venule end so water, dissolved solutes,glucose and amino acids diffuse back into the capilaries
- only about 90% the rest gos to the lympthatic system
Oxyhaemaglobin
- oxygen binds reversibility to the haemoglobin.
Describe the oxygen dissociation curve
- at low partial pressure(respiring tissue) the haemoglobin has a low affinity for oxygen so it has less saturated oxygen
- At a high partial pressure(e.g the lungs) Haemoglobin had a high affinity for oxygen so it has a high saturation of oxygen
The graph is an S-shape because when the first O2 molecule combines to haemoglobin it cause a conformation change making it easier for other molecules to bind too
- But as Hb becomes saturated it gets harder for more oxygen molecules to join too
Describe the Bohr effect
- reduces haemoglobins affinity for oxygen
-to prevent the build up of H+ ions in the blood Hb acts as a buffer - therefore H+ binds with Hb forming haemoglobinic acid
-the alters the structure of Hb - more oxygen is released for Hb where needed
How are hydrocarbonate ions formed
- carbon dioxide diffuses into the red blood cells
-the carbon dioxide combines with water forming carbonic acid catalysed by the enzyme carbonic anhydrase
-carbon acid dissociates to form hydrocarbonate ions and hydrogen ions
Fetal haemoglobin
- has a higher affinity for oxygen at low partial pressure than adult haemoglobin
-At the placenta there is a lower partial pressure of oxygen because some some oxygen has been used up by the mothers body so for the Cetus to survive it needs to have a higher affinity at lower PO
Bradycardia
Slow heart rate
Tachycardia
Fast heart rate
Atrial fibrillation and ventricular fibrillation
Artia is beating more frequently than ventricles. No clear P wave seen.
- ventricular is beating more frequently= more frequent Qrs complex
order of blood vessels
-arteries
-arterioles
-capilaries
-venules
-veins
how to discet a heart
-use a scapel to cut from the ventricle up thrpugh to the artium to be able to see both sides od the heart
how is heart action initiated and coordinated
-SAN initiates a wave of excitation
-wave spreads over atrial walls
-this causes the atria to contract
the contaction is synchronised
-The wave of ecitation passes to the AVN which causes a delay to ensure the atria is fully emptied
-excitation spreads down the Bundle of is to the purkyne tissues surrounding the ventricle walls
-this causes the ventricles to contract
ECG stand for
- Electrocardiogram
What does the letter stand for in a EEG
P- atria contraction
- QRS complex ventricular contraction
T- ventricles relax
You can compare between the start of a P wave and T wave
Explain the chloride shift
-Hydrocarbonate ions leave the red blood cells
- to balance out the charge Chlorine ions are diffused into the red blood cells
Describe the role of haemoglobin in transporting oxygen around the body
-Hb has a high affinity for oxygen
-oxygen bind to Hb in the lungs
- oxyhameoglobin is formed
-oxygen is released where needed
