System Unit

• Circulatory System Major Functions?

  1. Protection + Repair - WBC’s protect against illness/infection
  2. Transportation - O2 and CO2, nutrients, water, WBC’s, platelets, heat
  3. Regulation - homeostasis
• What organisms have an open circulatory system?

  Insects
• What is an open circulatory system?

  Blood flows freely within the body cavity and makes contact with organs & tissues
• What organisms have a closed circulatory system?

  Mammals, have 4 chambered hearts
• What is a closed circulatory system?

  Blood is physically contained within vessels and are separate from other body tissues
• What two loops of circulation do mammals have?

  The pulmonary circuit and systemic circuit
• What is the pulmonary circuit?

  Heart to lungs then lungs to heart
• What is the systemic circuit?


  Heart to body then body to heart
• What are the 3 different types of blood vessels?

  Arteries, capillaries and veins
• What do arteries do? 


  Carry blood AWAY from the heart
• What do veins do?

  Carry blood TO the heart, closer to skin’s surface
• What do capillaries do?

  Capillaries facilitate the exchange of oxygen, nutrients, and waste products between the bloodstream and surrounding tissues.
• What are the formed elements?

  WBC’s, RBC’s, platelets
• What is the liquid component of blood?

  Plasma, is yellow and mostly H2O
• Why do veins have valves?


  To allow blood flow only towards the heart and to prevent backwards flow when closed. Helps fight against gravity
• Another term for RBC’s


  erythrocytes
• another term for WBC’s

  leukocytes
• another term for platelets

  thrombocytes
• Red blood cells…

  Make up 44% of blood volume and are specialized in transporting oxygen
• Plasma makes up how much of blood volume?


  55%
• White blood cells…


  Make up 1% of total blood volume but this may increase when your body is fighting an infection
• Platelets do what ?

  Help with blood clotting from an injury
• What are the electrical signals carried by nerves called?

  Action potentials (AP)
• Where are action potentials produced?


  The sinoatrial node (RIGHT ATREUM)
• Bottom tip of the heart is called what?

  Apex
• What is an electrocardiogram?

  Produces a graph that shows the electrical activity of the heart (QRS complex)
• What happens when cardiac muscles receive action potential?

  They contract, allowing blood to be pumped
• Why do RBC’s have a bioncave shape? 


  To increase surface area for gas exchange and their lack of nucleus makes them more flexible to travel through body tissues
• In what order does blood enter the heart?

  Vena cava, right atrium, right ventricle, pulmonary arteries
• Importance of plasma


  Contains proteins to help resists against infections, adjusts body’s fluid balance, muscle contraction + nerves
• Ventricular diastole is when…

  Heart ventricles at rest filling up with blood
• Ventricular systole is when…

  Heart ventricles are contracting and pushing blood through the arteries
• The valve separating the right atrium and ventricle is called..?

  The tricuspid valve
• The valve separating the left atrium and ventricle is called the..?

  Bicuspid valve
• The pulmonary valve takes blood from the right ventricle into the…pulmonary arteries
• The vena cava carries …. blood into the heart?

  Deoxygenated
• The aorta carries _ blood to the body?

  Oxygenated
• What pitch is the first heart sound?

  Low pitched, ”lub” produced at the beginning of systole when the atrioventricular valves close
• What pitch is the second heart sound?

  High pitched, ”dub”, occurs at the end of ventricular systole, produced by closure of pulmonary + aortic valves
• Systole is what?

  the contraction of a heart chamber