CV system

• explain systemic circulation

  between the heart and the body. the left atrium pumps blood to the left ventricle via the bicuspid valve then leaves through the aorta towards the body. oxygenated blood is recieved from the lungs to the left atrium through the pulmonary vien.
• explain pulmonary circulation

  between the heart and the lungs. the right atrium recieves deoxygenated blood from the vena cava which then goes to the right ventricle through the tricuspid valve. then out of the right ventricle to the lungs via the pulmonary artery.
• systole

  when the heart contracts and pumps blood out
• diastole

  when the heart relaxes and the chambers fill with blood
• what is the cardiac conduction system

  SA node

  AV node causes the atriums to contract and pump blood into the ventricles.

  Bundle of HIS start ventricular contraction which sends a impulse to the purkinge fibres to cause the ventricles to contract and pump blood to the body or lungs.

  - intrinsic contol of heart rate

  - heart muscle is myogenic
• what contols blood pressure

  vasomotor system
• what is anticipatory rise

  heart rate rises before exercise due to adenaline
• adrenaline

  hormone that speeds up heart rate before exercise
• acetylcholine

  hormone that slows down heart rate
• what is the sympathetic nervous system

  increases heart rate down the accelerating nerve
• what is the parasympathetic system

  slows down heart rate down the vagus nerve
• medulla oblongata

  part of the brain that detects signals from the muscles

  CCC- cardiac control center
• chemoreceptors

  detect changes in carbon dioxide levels in the blood
• baroreceptors


  detect changes in blood pressure
• proprioceptors

  detect movement
• srtoke volume

  the volume of blood pumped out of the left ventricle in one beat

  increases during exercise

  at rest = 70ml
• cardiac output

  the volume of blood pumped out of the left ventricle in one minute

  increase during exercise

  Q=SV x HR

  at rest = 4900ml
• ejection fraction

  fraction of blood ejected from the left ventricle in one beat

  increase during exercise

  fitter people leave less blood
• bradycardia

  heart rate under 60bpm
• maximum HR

  220-age
• starlings law

  what leaves the heart must come back
• venous return

  the amount of blood returing back to the heart
• venous return mechanisms

  pocket valves - prevent backflow

  sketetal muscle pump - muscle contract squeezing blood back

  respiatory pump = pressure changes when we breathe in and out which helps suck blood back
• blood pressure and what controls it

  the pressure exerted on the artery walls as blood flows through it

  vasomotor center contols it
• systolic pressure

  pressure on the artery walls as the heart contracts and pumps blood - leaves the heart
• diastollic pressure

  pressure on the artery walls as the heart relaxes and fills with blood
• explain vascular shunt

  - vasocinstriction and vasodialation

  - chemoreceptors and proprioceptors send signals to the CCC to know when to redistribute blood

  - vasomotor centre contols it
• vasoconstriction

  blood vessles constricting
• vasodialation

  blood vessels opening
• pre capillary sphincters

  when we aren't eating it constricts when when the digestive system needs oxugen it dialates

  located in the opening if capilaries
• why does blood go to the skin during exercise

  to help us cool down during exercise
• what is atrio-venous difference

  the difference in the amount of oxygen in the arteries and viens.

  how much is extracted and used
• cardiovascular drift

  - explaination for why heart rate increases even when exercising at a steady state

  - when we are exercising the body cools us down through evaporation (sweat) and radiation (red face)

  - blood gets more viscise + venous return decreases

  - as a result, HR increases to keep suppling the working muscles with oxygen
• adaptations to training - CV system

  - lower resting HR

  - decreased blood pressure

  - increased stroke volume

  - increased cardiac output

  - cardiac hypertrophy

  - resynthesise ATP quicker

  - more capillaries

  - improved development of mitochondria
• plasma

  3% of oxygen is dissolved in the plasma
• haemoglobin


  oxygen sticks to the haemoglobin in the blood which creates oxyhaemoglobin
• myoglobin

  oxygen-store unit, provides oxygen to working muscles
• mitochondia

  power house of the cell, aerobic respiration takes place
• oxygen dissociation

  - in the lungs there is a high concentration on carbon dioxide which dissociates with the haemoglobin and diffuses out of the lungs

  - there is a high concentration of oxygen in the blood which associates with haemoglobin in the lung and difffues into the lungs

  - in the muscles there is a high concentration of carbon dioxide which associates with haemoglobin in the muscles

  - there is a low concentration of oxygen which dissocations with haemoglobin
• explain the Bohr shift/effect

  rising carbon dioxide levels in the tissue decreases the affinity of haemoglobin for oxygen. so there is a greater dissocation of oxygen from haemoglobin, this increases the amount of oxygen released to the tissue.