Component 3 - Animal Transport Flashcards
What is an open circulatory system
Blood is pumped into a haemocoel where it bathes organs and returns slowly to the heart with little control over direction of flow. Blood is not contained in blood vessels
What is a closed Circulation System
Blood is pumped into a series of vessels; blood flow is rapid and direction is controlled.
Organs are not bathed by blood but by tissue fluid that leaks from capillaries
What is a single circulation system
Blood passes through the heart once in each circulation
What is a double circulatory system
Blood passes through the heart twice in each circulation – once in the pulmonary (lung)
circulation and then again through the systemic (body) circulation.
Describe the circulatory system of Earthworms
- Closed circulatory.
- 5 pseudohearts.
- Respiratory pigment haemoglobin carries respiratory gases in blood.
Describe the circulatory system of insects
- Open circulatory system
- dorsal tube-shaped heart.
- No respiratory pigment in blood as lack of respiratory gases in blood due to tracheal gas exchange system
Describe the circulatory system of Fish
- Closed, single circulatory system.
- Blood pumped to and oxygenated in the gills continues around body tissues.
- This means a lower pressure and slower flow around the body
Describe the circulatory system of Mammals
- Closed, double circulatory system.
- High blood pressure to body delivers oxygen quickly.
- Lower pressure to lungs prevents hydrostatic pressure forcing tissue fluid into and reducing efficiency of alveoli
What is the function of the Aorta
carries oxygenated blood from the left ventricle to the body
What is the function of the Pulmonary Artery
takes deoxygenated blood to lungs from right ventricle
What is the function of the Pulmonary (semilunar) Valve
there is a similar valve in the aorta. They prevent blood flowing back into the ventricles between heart beats
What is the function of the Pulmonary Veins
return oxygenated blood from lungs to the left atrium
What is the function of the Bicuspid (mitral) Valve
prevents backflow of blood into the left atrium when the ventricles contract
What is the function of the Left Ventricle
prevents backflow of blood into the left atrium when the ventricles contract
What is the function of the Septum
wall dividing oxygenated blood (left) and deoxygenated blood (right) side of the heart
What is the function of the Right Ventricle
thinner muscular wall compared to the left ventricle as less pressure is produced on contraction
What is the function of the Tricuspid Valve
thinner muscular wall compared to the left ventricle as less pressure is produced on
contraction
What is the function of the Right Atrium
contracts and pumps deoxygenated blood into the right ventricle
What is the structure of an Artery
- Tough collagen outer coat to prevent overstretching
- Small lumen surrounded by smooth endothelium to prevent friction
- Thick layer of smooth muscle that contracts and
relaxes to alter blood flow to different organs.
Thick layer of elastic tissue recoils to propel blood
forward and even out flow
What is the structure of a vein
- Tough collagen outer coat to prevent overstretching
- Larger lumen as blood is under lower pressure. This gives less resistance to blood flow
- Less muscle and elastic fibres. Instead, veins contain semilunar valves to prevent backflow of blood
What is the structure of a capilliary
A single layer of endothelium giving a short diffusion path
How is the heartbeat initiated
- The heartbeat is myogenic
- The sinoatrial node acts as a pacemaker sending waves of excitation across the atria causing them to contract simultaneously
- A layer of connective tissue prevents the wave of excitation passing down to the ventricles. The wave of excitation passes to the atrio-ventricular node where there is a delay to allow the atria to complete contraction
- The atrio-ventricular node transmits impulses down the bundle of His to the apex of the heart
- The impulse then travels up the branched Purkinje fibres, simulating ventricles to contract from the bottom up. This ensures all the blood is pumped out
Name the Cardiac Cycle
- Atrial Systole
- Ventricular Systole
- Ventricular Diastole
- Diastole
What is Atrial Systole
- Atrial contract
- Pressure opens atrio-ventricular valves
- Blood flows into ventricles
What is Ventricular Systole
- Ventricles contract
- Atrio-ventricular valves close due to pressure in ventricles being higher than that in the atria
- Semilunar valves in aorta and pulmonary artery open
- Blood flows into arteries
What is Ventricular Diastole
- Ventricle muscle relaxes
- Semilunar valves close to prevent backflow of blood into the ventricles
What is Diastole
Heart muscle relaxes and atria begin to fill from vena cava and pulmonary veins
How is the electrical activity detected and what is it displayed as
A cathode ray oscilliscope ECG
On an ECG, what is the P wave - the small bump before the big one
Depolarisation of the atria corresponding to atrial systole
On an ECG, what is the QRS wave
Spread of depolarisation through the ventricles resulting in ventricular systole
On an ECG what is the T wave - The last small one
Repolarisation of the ventricles resulting in ventricular diastole
How is CO2 carried in the blood
- Some carried in the blood dissolved in plasma
- Scarried in the blood as carbaminohaemoglobin
- Most is carried as hydrogen carbonate ions
Explain the processes of the Chloride shift
- CO2 diffuses into a red blood cell (RBC).
- CO2 combines with H2O catalysed by the enzyme carbonic anhydrase, forming carbonic acid.
- Carbonic acid dissociates into hydrogen ions (H+) and hydrogen carbonate ions (HCO3-) diffuse out of the RBC into the plasma.
- Chloride ions (Cl-) diffuse (facilitated diffusion) into the RBC to maintain electrochemical neutrality – the chloride shift.
- H+ bind to oxyhaemoglobin, reducing its affinity for oxygen. This is the Bohr effect.
- Oxygen is released from the haemoglobin.
- Oxygen diffuses from the RBC into the plasma and body
cells.
