circulatory system & Heart

• The atria are the upper chambers of the heart that filled with blood vessels from the veins.
• The lower chambers of the heart are called the ventricles and they pump blood through arteries
• Deoxygenated blood passes through the right and oxygenated blood leaves through the left
• The left and right sides of the heart are separated by the septum
• Blood flows in one direction through arteries due to the pressure from the heart beat and in veins due to valves
• When needed, blood vessels contain muscles which allows them to narrow or contract reducing blood flow
• Blood vessels can dilate which widens the vessels increasing blood flow, this helps regulate body temperature
• A


  1

  3

  6

  10
• C


  5

  8

  13
• How do doctors measure heartbeats? What blood vessels are involved?

  With each heartbeat, the arteries stretch and bulge from the force of the blood pumping. This bulge of the artery is called a pulse. A pulse is used to measure heart rate. It is felt by fingers pressing on an artery and measured in bpm.
• What is the difference between and open and closed circulatory system? Give example organisms for each type.

  Open: They have no blood vessels. Instead, hemolymph is pumped into body cavities where it contacts the body cells directly. (spiders, snail, slugs)

  Closed: Blood is always contained in blood vessels. Blood is kept separate from interstitial fluid (Kangaroos, humans, earthworm)
• Distinguish between the three types of blood vessels in terms of function, and walls.

  Arteries: directs blood away from the heart and into organs, thick but elastic walls

  Veins: direct deoxygenated blood towards the heart, thin walls

  Capillaries: site of oxygen, nutrient and waste exchange between bloodstream and tissue, one cell thin walls
• How do varicose veins occur?

  The valves of the veins do not close completely, and blood may flow and pool in the opposite direction.
• The heart is an organ of which body system?


  circulatory system
• What is the name of the muscular layer of the heart?

  myocardium
• What is the name of the bag that surrounds the heart?

  pericardium
• The tissue of the heart, the myocardium, is composed primarily of what type of cells?

  cardiac muscle cells
• What is the function of the heart?

  To pump blood around the body through blood vessels
• Which side of the heart has a thicker ventricular wall? Why?

  Left ventricle pumps oxygenated blood to the whole body
• What valves are found between the atria and ventricles?

  Atrioventricular valves
• What structure divides the two ventricles of the heart

  septum
• The superior vena cava attaches to which chamber?

  the right atrium
• What is the largest artery in the human body?

  aorta
• What is the name of the contraction phase of the cardiac cycle?


  Systole
• What is the name of the relaxation phase of the cardiac cycle?

  Diastole
• How can a heart attack happen?

  Coronary artery gets blood, limiting blood supply to the heart muscle
• things which are transported by the circulatory system.

  Oxygen, carbon dioxide, nutrients, hormones, heat, waste (to kidneys & liver).
• What is the difference between oxygenated and deoxygenated blood?

  Oxygenated blood has oxygen bound to hemoglobin in red blood cells. Deoxygenated blood has no oxygen (or very little), and may have CO2
• When blood is pumped out of the heart, the blood enters what type of blood vessel?

  artery