Paper 1

• pulmonary circuit


  circulation of blood through pulmonary artery to the lungs and pulmonary vein back to the heart
• systemic circuit


  circulation of blood through aorta to the body and vena cava back to the heart
• myogenic


  muscle tissue that has the capacity to generate its own electrical impulse that passes through muscular walls, forcing them to contract
• SA (Sino-atrial) node


  located in the right partial wall, it generates electrical impulse and forces walls to contract
• AV (atrio-ventricular) node


  it collects the impulse and delays it for 0.1 seconds to allow the atria to finish contracting.
• Bundle of His


  located in the septum of the heart, it splits the impulse in two, so its ready to be distributed through each separate ventricle
• bundle branches


  it carries impulse to base of each ventricle
• purkyne fibres


  these distribute impulse through ventricle walls, causing them to contract
• cardiac dystole


  the relaxation phase of the cardiac cycle
• cardiac systole


  the contraction phase of the cardiac cycle
• diastole


  As the atria then ventricles relax, they expand; drawing blood into the atria

  The pressure in the atria increase, opening av valves

  Blood passively enters the ventricles

  SL valves close to prevent blood leaving the heart
• atrial systole


  the atria contract, forcing remaining blood into ventricles
• ventricular systole


  the ventricles contract, increase pressure closing AV valves to prevent back flow into atria

  SL valves and forced open as blood is ejected from ventricles into the aorta and pulmonary artery
• AV valves


  bicuspid and tricuspid valves
• SL valves


  semilunar valves (in arteries leaving the heart)
• heart rate


  number of times the heart beats per minute
• stroke volume


  the volume of blood ejected from the left ventricle per beat
• cardiac output


  the volume of blood ejected from the left ventricle per minute

  Q = HR x SV
• Bradycardia


  RHR below 60bpm
• 220-age


  heart rate max
• venous return


  the return of blood to the right atria through the veins
• venous return methods


  1. pocket valves

  2. smooth muscle

  3. gravity

  4. muscle pump

  5. respiratory pump
• submaximal exercise


  low to moderate intensity exercise within performers aerobic capacity
• maximal exercise


  a high intensity of exercise above a performer's aerobic capacity that will induce fatigue
• chemoreceptor


  located in the muscles, aorta and arteries inform the CCC of chemical changes in the blood stream, such as CO2 or lactic acid
• proprioceptors


  located in the muscles, tendons and joints inform CCC of motor activity
• baroreceptors


  located in blood vessels inform CCC of blood pressure
• cardiac control centre


  receives information from the sensory servers and sends direction through motor nerves to change HR
• intrinsic control


  temperature change - affects viscosity of blood and speed of nerve impulse transmission

  venous return changes - affects stretch in ventricle walls, force of ventricular contraction and therefore stroke volume
• hormonal control


  adrenaline and noradrenaline are released from the adrenal gland increase force of ventricular contraction and increasing spread of electrical activity through the heart
• sympathetic nervous system


  responsible for increasing HR, releasing adrenaline, noradrenaline and sending stimulation to the SA node via the cardiac nerve
• parasympathetic nervous system


  responsible for decreasing HR, inhibit effects via the vagus nerve lowering HR
• medula oblongata


  part of the brain that controls breathing, heartbeat, and the size of blood vessels
• vasodilation


  widening of arteries, arterioles and pre-capillary sphincters
• vasoconstriction


  narrowing of arteries, arterioles and pre-capillary sphincters
• pre-capillary sphincters


  rings of smooth muscle at the junction between arterioles and capillaries, which can dilate or constrict to control blood flow through the capillary bed
• vascular shunting


  the redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to the skeletal muscles
• arterioles


  blood vessels carrying oxygenated blood from the arteries to the capillary beds, which can vasodilate and vasoconstrict to regulate blood flow
• vasomotor control centre (VCC)


  the control centre in the medulla oblongata responsible for cardiac output distribution
• vasomotor tone


  the partial state of smooth muscle constriction in the arterial walls