Cardiovascular System

• Atherosclerosis 


  The hardening and narrowing of arteries due to fatty deposit build ups
• Carbon Monoxide in the Blood

  Affects the red blood cells

  Combines with hemoglobin and reduces the capacity of red blood cells
• Chambers of the Heart

  2 Atriums (Left and Right)

  2 Ventricles (Left and Right)
• Valves of the Heart

  Bicuspid valve - connect left atrium and left ventricle

  Aortic Semilunar valve - connect the left ventricle and the aorta

  Tricuspid valve - connect right atrium and right ventricle

  Pulmonary Semilunar valve - connect right ventricle and pulmonary artery
• Cardiac Conduction System 


  SA node - AV node - Bundle of His - Bundle of Branches - Purkinje fibres
• SA Node (Sino-Atrial Node)


  Contraction at the heart begins here

  Spreads through the heart in waves rather than one contraction
• AV Node (Atria-Ventricular Node)

  Electrical impulses spread through the walls of the heart

  Reaches the AV Node which delays the spread by 0.1 seconds
• Bundle of His


  Specialized bundle of nerve cells located in the Septum

  Spreads the electrical signal
• Purkinje Fibres 


  Spread the signal through the ventricles

  The contraction is called Ventricular Systole
• Chemoreceptors 


  Found in the arteries and aorta

  Detect an increase in carbon dioxide

  Stimulates an increase in heart rate
• Starling's Law


  The more blood that enter the heart = the more elasticity in the heart fibre

  The more elasticity the more powerful the contractions

  Ejection fracture = %of blood pumped out the left ventricle per heart beat
• Contractility of the Cardiac Tissue

  The more powerful the heart = the greater the stroke volume

  Due to an increased ejection fraction

  Normal Adult = 60%

  Trained Adult = 85%
• Heart Rate 


  Number of times the heart beats per minute

  Average resting value = 72bpm

  Unfit = over 72bpm

  Fit = under 72bpm
• Cardiac Output 


  Q = HR X SV
• Heart Rate Response to Exercise

  Short Term:

  Increased HR to match intensity

  Max HR = 220-Age

  Long Term:

  Max HR increases

  Bradycardia decreased resting HR
• Heart Disease 


  Coronary Heart Disease

  Blocking and narrowing or artery = atheroma

  Caused by high blood pressure, high cholesterol, lack of exercise
• Angina 


  Pain and discomfort caused by the narrowing of the arteries

  Lack of oxygen to the heart

  If atheroma's beak off it can cause heart attacks
• Preventing Heart Disease 


  Regular exercise keeps the heart efficient

  Cardiac hypertrophy pumps more blood around the body

  Increased SV

  Improved flexibility and elasticity of the blood vessels
• High Blood Pressure 


  Known as hypertension

  Caused by hardening of the arteries and reduction in the lumen

  Aerobic exercise increases health of blood vessels
• Cholesterol 


  LDL - transports cholesterol in the blood tissue, increased chance of a heart attack

  HDL - transports excess cholesterol to the liver where it can be broken down
• Stroke 


  Occurs when the blood is cut off from the brain

  Can lead to permanent and life changing damage

  Regular exercise can drastically reduce chances of a stroke
• Cardiovascular Drift 


  An increase in HR while working at the same intensity

  Changes to Cardiac Output, Stroke Volume and Heart Rate during a period of steady exercise

  Occurs due to a loss of fluid and increased blood viscosity
• Blood Vessels 


  Heart - Arteries - Arterioles - Capillaries - Venules - Veins - Heart
• Blood Pressure 


  The force exerted on the walls of the blood vessels by the heart

  Increases during exercise due to demand
• Venous Return


  The amount of blood returning to the right side of the heart via the vena cava
• Venous Return Mechanisms


  Skeletal Pump

  Respiratory Pump

  Pocket Valves
• Skeletal Muscle Pump


  The changing shape of muscles causes pressure to be placed on the blood, creating a pump
• Respiratory Pump


  Pressure changes compress nearby veins and cause the pump of blood
• Pocket Valves 


  Valves only allow the flow of blood in one direction

  The open and closing of valves causes pressure and allows for greater force
• Transportation of Oxygen 


  97% of oxygen is transferred to the muscles during exercise and forms oxyhemoglobin

  Oxygen is released into the muscle during oxygen dissociation

  Mitochondria releases the energy which allows for contraction
• Myoglobin 


  Stores oxygen in the muscles

  Found in slow twitch fibres

  Has a higher affinity for oxygen and stores oxygen until it is needed

  Site of aerobic cell respiration
• Oxyhemoglobin Dissociation Curve 


  How hemoglobin in our blood transports and releases oxygen

  Association = O2 to HB

  Dissociation = O2 from HB

  Graph which measures the relationship between hemoglobin saturation and partial pressure of oxygen
• Bohr's Shift


  Where the Oxyhemoglobin Curve shifts to the right during exercise

  Extra oxygen is delivered to the legs

  Caused by blood temperature increase, pH levels in the blood, increased in Co2 partial pressure
• Control of Blood Flow

  Vasodilation - opening of blood vessels

  Vasoconstriction - closing or narrowing of blood vessels
• Pre-Capillary Sphincters 


  Rings of muscle which control blood flow through the certain capillary

  Helps in allowing or stunting blood flow
• A-VO2 Difference 


  Anterior-Venous Difference

  Rest - Low due to little oxygen present

  Exercise - High as muscles need more O2

  A difference between the presence of oxygen and carbon dioxide
• Baroreceptors 


  Found in the arteries

  Sense an increase in blood pressure

  Hold threshold points at rest and during exercise

  Send signals to the medulla oblongata to balance pressure
• Proprioceptors 


  Sensors located in the nerve endings of muscles and joints

  Detect an increase in movement and send impulses to increase or decrease heart rate
• Anticipatory Rise 


  The release of adrenaline prior to action

  Increases the speed and force of cardiac contraction

  More blood is pumped at a higher intensity