BY2 - Transport In Animals
- Created by: beth-marie2511
- Created on: 04-05-16 22:04
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- Transport in Animals (2)
- Heart Structure
- Right Hand Side
- Carries deoxygenated blood.
- Right atrium
- Right ventricle
- Pulmonary artery
- Takes blood to the lungs.
- Vena cava
- Veins which bring blood to the heart.
- Atrio-ventrixular valve
- Tricuspid
- Left Hand Side
- Carries oxygenated blood.
- Pulmonary vein
- Brings blood from the lungs to the heart.
- Aorta
- Atrio-ventricular valve
- Bicuspid
- Left ventricle
- Left atrium
- Septum is the separating wall between the left and right sides.
- Prevents blood flowing from one side of the heart to the other.
- Heart is made of cardiac muscle.
- Specialised tissue
- Capable of rhythmic contraction and relaxation of its own accord.
- MYOGENIC
- Has its own blood vessels.
- Coronary vessels
- Supply oxygen to the heart.
- Valves are connected by tendons
- Right Hand Side
- Cardiac Cycle
- 1. Atrial Systole
- Muscle wall of the atria contracts
- This forces blood through the open atrio-ventricular valves (bicuspid and tricuspid) and into the ventricles.
- Blood cannot flow backwards.
- This is because of a greater pressure in front of the valves that forces them to close.
- Blood cannot flow backwards.
- This forces blood through the open atrio-ventricular valves (bicuspid and tricuspid) and into the ventricles.
- Systole = Contract
- Contractions create pressure.
- Muscle wall of the atria contracts
- 2. Ventricular Systole
- Atria relaxes.
- Muscles in the wall of the left and right ventricles contract.
- Blood moves from the ventricles through the semi-lunar valves.
- This forces the valves to open.
- High pressure behind the valves causes them to open.
- Blood flows out and into the pulmonary artery and aorta.
- Tricuspid and bicuspid (atrio-ventricular valves) close because of the rise in pressure in the ventricles.
- This forces the valves to open.
- Blood moves from the ventricles through the semi-lunar valves.
- The ventricles contain more muscle than the atria so they generate more pressure to force the blood a greater distance.
- Ventricular Diastole
- Muscles in the wall of the atria and ventricles relax.
- Pressure inside the ventricles falls and the volume (space) increases.
- Blood would flow back into the aorta and pulmonary artery but the semi-lunar valves are forced shut because there is a high pressure in front of the valves.
- Pressure inside the ventricles falls and the volume (space) increases.
- During diastole the elastic rebound of the aorta helps to maintain arterial pressure.
- Diastole = Relax
- Muscles in the wall of the atria and ventricles relax.
- Blood from the vena cava and pulmonary vein enters the atria and the cycle starts over.
- The left ventricle has a thicker muscle than the right ventricle.
- It has to pump the blood all around the body while the right ventricle only has to pump it to the lungs.
- Atrial Systole
- High atrial pressure
- Low ventricular pressure
- Atrio-ventricular valves open
- Semi-lunar valves close.
- Ventricular Systole
- Diastole
- Low atrial pressure
- Low ventricular pressure
- Atrio-ventricular valves open
- Semi-lunar valves close
- 1. Atrial Systole
- How is the cardiac cycle initiated and controlled?
- Atrio-ventricular Node
- Receives impulses from the Sino-Atrial Node and passes the impulses onto the Purkyne Fibres.
- Allows for a delay which stops the atria and ventricles from contracting at the same time.
- Purkyne Fibres pass the impulse to the apex.
- Apex = Bottom of the heart
- Receives impulses from the Sino-Atrial Node and passes the impulses onto the Purkyne Fibres.
- Purkyne Fibres / Bundle Of His
- Conducts the impulses to the ventricles and ensures the heart contracts from the apex up.
- This forces the atrial walls to contract up from the apex and pumps blood into the aorta.
- Conducts the impulses to the ventricles and ensures the heart contracts from the apex up.
- Sino-Atrial Node
- Generates electrical impulses
- They cannot pass to the ventricles on their own
- Causes the atrial muscles to contract
- Initiates impulses
- Specialised cardiac fibres
- Acts as a pacemaker
- Sets the pace of the cardiac cycle
- Acts as a pacemaker
- Generates electrical impulses
- What can change the cycle?
- Adrenaline
- Increases heartbeat
- Exercise
- Increases heartbeat
- Adrenaline
- Atrio-ventricular Node
- Heart Structure
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