1829214
Description
Mind Map by Katie Kenney, updated more than 1 year ago
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Created by Katie Kenney
almost 10 years ago
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The Heart
- The Cardiac Cycle
- Atrial Systole - ventricles are relaxed, atria fill with blood decreasing
the volume and increasing the pressure forcing the atrioventricular
valves to open, allowing blood to flow into ventricles.
- Ventricular Systole - ventricles contract and atria relax, pressure is higher in ventricles
than in atria so the AV valves close to prevent backflow, high pressure in ventricles
opens semilunar valves forcing blood out into the pulmonary artery and aorta
- Diastole - atria and ventricles both relax increasing the volume and lowering the pressure, the higher
pressure in pumonary artery and aorta forces the semi lunar valves to closepreventing backflow, the
atria fill with blood again due to the high pressure in the vena cava and pulmonary vein
- Atrial Systole - ventricles are relaxed, atria fill with blood decreasing
the volume and increasing the pressure forcing the atrioventricular
valves to open, allowing blood to flow into ventricles.
- cardiac muscle is MYOGENIC - it can
contract and relax without receiving
signals from nerves
- Controlling a Regular Heartbeat
- process starts in the sino atrial
node in the wall of the right atrium
- the SAN sends out regular waves of electrical activity to the atrial
walls causing the right and left atria to contract at the same time
- a band of non-conducting collagen tissue prevents the waves of electrical
activity from being passed directly from the atria to the ventricles
- instead, the waves are transferred from the SAN to the atrioventricular node. the
AVN passes the waves onto the bundle of His, but theres a slight delay before the
AVN reacts to make sure the ventricles contract after the atria have emptied
- the bundle of His conducts the waves to the Purkyne tissue, which
carries the waves into the walls of the right and left ventricles
causing them to contract simultaneously from the bottom upwards
- the bundle of His conducts the waves to the Purkyne tissue, which
carries the waves into the walls of the right and left ventricles
causing them to contract simultaneously from the bottom upwards
- instead, the waves are transferred from the SAN to the atrioventricular node. the
AVN passes the waves onto the bundle of His, but theres a slight delay before the
AVN reacts to make sure the ventricles contract after the atria have emptied
- a band of non-conducting collagen tissue prevents the waves of electrical
activity from being passed directly from the atria to the ventricles
- the SAN sends out regular waves of electrical activity to the atrial
walls causing the right and left atria to contract at the same time
- process starts in the sino atrial
node in the wall of the right atrium
- Electrocardiograph
- P wave - contraction of atria QRS
complex - contraction of
ventricles T wave - relaxation of
ventricles
- Heart Problems
- Trachycardia - fast heartbeat (around 120 beats per min),
if at rest heart won't be pumping blood out efficiently
- problem with AVN - impulses aren't travelling
from the atria through to the ventricles
- Fibrillation - really irregular heartbeat, heart loses it's
rhythm and stops contracting properly, can lead to death
- Trachycardia - fast heartbeat (around 120 beats per min),
if at rest heart won't be pumping blood out efficiently
- P wave - contraction of atria QRS
complex - contraction of
ventricles T wave - relaxation of
ventricles
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