Blood Vessels Heart and Circulation System

AQA GCSE BIOLGY B3

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  • Created by: nom
  • Created on: 08-06-08 14:43

Heart

The heart is:

  • a pump
  • situated in the thorax (chest cavity) - slightly to left
  • the size of a clenched fist
  • always drawn as though it is in the animal- lying on its back

Deoxygenated blood - blood going to the heart / lungs not carrying oxygen

Oxygenated blood - blood going to the rest of the body containing oxygen

pulmonary artery - goingto the lungs

pulmonery vein - going to the heart - from lungs

aorta - main artery of the body - leaving heart

vena cava - main vein of body - going to heart

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Blood Vessels

veins:

  • carry deoxgenated blood to the heart
  • don't have a pulse - have valves to prevent back-flow of blood
  • have thin walls - large lumen (hole inside)

arteries:

  • carry oxygenated blood away from the heart
  • stretch as blood is forced through them - go back into shape afterwards - feels like pulse where they go close to the surface
  • have thick walls + small lumen + thick layer of muscle+elastic fibres

Capillary :

  • narrow walls a single cell thick so oxygen+glucose can pass from blood into cells easily - diffusion + carbon dioxide can pass from cells into blood
  • tiny vessel with narrow lumen
  • take blood from arteries to body cells to veins
  • walls
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Double Circulation System

Blood passes through the heart twice for every 1 circulation around the body

2 separate systems supply the lungs + the rest of the body

Blood travels in aCONTINUOUScircuit round the body

Gut -> blood vessel -> Liver -> Vena Cava->Heart -> Pulmonary Artery -> Lungs -> Pulmonary Vein -> Heart -> Aorta

Red Blood cells:

  • contains haemoglobin -> when lots of oxygen-> OXYHAEMOGLOBIN
  • shape - biconcave disk - increases surface area - allows for more absorption of oxygen
  • have no nucleus

Whit blood cells:

  • have a nucleus
  • 2 types lymphocytes + phagocytes
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Pulse Rate

Pulse Rate - measure of how quickly the heart beats -depressing an artery - makes you able to feel it

Muscle cells contract during exercise -> using energy -> released from respiration ->reaction between oxygen + glucose

heart beats faster using oxygen -> transports more oxygen + glucose to cells + removes waste carbon dioxide

exercise makes- heart rate increase + rate+depth of breathing increase +arteries supplying muscles dilate

All of these increase flow of blood to muscles - INCREASES supply of glucose + oxygen + INCREASES removal of carbon dioxide

Rate of breathing increaes/decreases after change in pulse rate - body needs to detect changes due to increased muscle activity

Glucose is stored as glycogen = glycogen stores in muscles + used during exercise

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