Circulatory System

• Circulatory System


  Responsible for transporting materials throughout the entire body
• Circulatory System

  • Transports nutrients, water, and oxygen to body cells
  • Carries away wastes such as carbon dioxide that body cells produce
  • An amazing highway that travels through your entire body connecting all your body cells
• Gases transported to and from body cells

  • Carbon dioxide
  • Oxygen
• Oxygen is the gas needed for respiration and is transported to the body's cells
• Blood in circulatory system

  • Oxygen-rich blood
  • Oxygen-poor blood
• Arrangement of circulatory system means that oxygen-rich and oxygen-poor blood do not mix
• Components of circulatory system

  • Heart
  • Blood
  • Vessels
  • Arteries
  • Veins
  • Capillaries
• Heart


  Organ at the centre of the circulatory system that pumps blood around the body
• Heart

  • Divided into two sections to keep oxygen-rich and oxygen-poor blood apart
  • Right side contains oxygen-poor blood
  • Left side contains oxygen-rich blood
• Heart structure

  1. Septum separates right and left sides

  2. Atria (upper chambers) receive blood

  3. Ventricles (lower chambers) pump blood out of heart
• Heart chambers

  • Two atria (upper chambers)
  • Two ventricles (lower chambers)
• Valves

  • Connected to inner walls of heart by tough tendons
  • Allow valves to close and hold valve flaps in place
  • Prevent valves from flipping up and turning inside out
• Valves act like a door that only opens in one direction
• Tendons holding valves are like the arm holding the door, allowing valve to only open in one direction
• How heart pumps blood

  • Heart is made of muscle that contracts (squeezes) and relaxes
  • Parts of heart work together in a repeated sequence - atria contract and relax, then ventricles contract and relax
  • This is how blood moves through heart and is pumped to lungs and body
  • One complete sequence of contraction and relaxation is a heartbeat
• Path of blood through circulatory system

  1. Superior/Inferior Vena Cava

  2. Right Atrium

  3. Tricuspid Valve

  4. Right Ventricle

  5. Pulmonary Valve

  6. Pulmonary Artery

  7. Lungs

  8. Pulmonary Vein

  9. Left Atrium

  10. Mitral Valve

  11. Left Ventricle

  12. Aortic Valve

  13. Aorta

  14. Body
• Types of blood vessels

  • Arteries (carry blood away from heart)
  • Capillaries (link arterioles to veins)
  • Veins (carry blood towards heart)
• Arteries

  • Large vessels
  • Carry oxygen-rich blood (except pulmonary arteries)
  • Thick walls to withstand pressure from heart
• Capillaries


  • Smallest blood vessels
  • Walls are only one cell thick and very narrow
  • Important for bringing nutrients and oxygen to tissues and absorbing CO2 and other waste products
• Veins


  • Contain connective tissue and smooth muscle
  • Largest veins contain one-way valves to keep blood flowing towards heart
  • Many found near skeletal muscles, which contract to force blood through veins
• Blood pressure


  The force of blood on the walls of the arteries
• Measuring blood pressure


  1. Cuff is wrapped around upper arm and pumped with air until blood flow is blocked

  2. As pressure in cuff is relaxed, two numbers are recorded:

  Systolic pressure - force when ventricles contract

  Diastolic pressure - force when ventricles relax
• Blood composition


  Plasma (55%)

  Cellular components (45%)
• Types of blood cells

  • Red blood cells

  White blood cells

  Platelets
• Plasma


  Straw-colored

  90% water

  10% dissolved gases, salts, nutrients, enzymes, hormones, wastes, and proteins
• Plasma proteins


  Albumins and globulins - transport substances

  Fibrinogen - responsible for blood clotting
• Red blood cells


  • Most numerous type

  Transport oxygen

  Get color from hemoglobin

  Disk-shaped

  Made in red bone marrow

  Circulate for 120 days
• White blood cells

  • Guard against infection, fight parasites, and attack bacteria

  Number increases when body is fighting
• Lymphocytes


  Produce antibodies which fight pathogens and remember them
• Platelets


  • Aid the body in clotting

  Small fragments

  Stick to edges of broken blood cells and secrete clotting factor to help form clot
• Types of white blood cells

  • Granulocytes (basophils, neutrophils, eosinophils)

  Agranulocytes (lymphocytes, monocytes)
• Main functions of blood

  • Transport

  Protection

  Temperature regulation
• Circulatory System

  Responsible for transporting materials throughout the entire body
• Circulatory System

  • Transports nutrients, water, and oxygen to body cells
  • Carries away wastes such as carbon dioxide that body cells produce
  • An amazing highway that travels through your entire body connecting all your body cells
• Gases transported to and from the body's cells

  • Carbon dioxide
  • Oxygen
• Oxygen is the gas needed for respiration and is transported to the body's cells
• Two types of blood in the circulatory system

  • Oxygen-rich blood
  • Oxygen-poor blood
• Arrangement of the circulatory system means that the two types of blood do not mix
• Components of the circulatory system

  • Heart
  • Blood
  • Vessels
  • Arteries
  • Veins
  • Capillaries
• Heart

  The organ at the centre of the circulatory system that pumps blood around the body