WEEK 11

• Cardiovascular system


  The system that pumps blood through the body
• Heart


  • Complex muscle that pumps blood through the three divisions of the circulatory system: coronary, pulmonary, and systemic
• Coronary circulation


  Blood taken directly from the aorta to the heart
• Pulmonary and systemic circulation


  Heart pumps blood to the lungs or the rest of the body
• In vertebrates, the lungs are relatively close to the heart in the thoracic cavity
• The shorter distance to pump means that the muscle wall on the right side of the heart is not as thick as the left side which must have enough pressure to pump blood all the way to your big toe
• Circuits of the mammalian circulatory system

  • Systemic circuit
  • Pulmonary circuit
  • Coronary circuit
• Blood flow through the circulatory system

  1. Pumped from veins of the systemic circuit into the right atrium

  2. Into the right ventricle

  3. Enters the pulmonary circuit and is oxygenated by the lungs

  4. Re-enters the heart through the left atrium

  5. From the left ventricle, blood re-enters the systemic circuit through the aorta and is distributed to the rest of the body
• The coronary circuit, which provides blood to the heart, is not shown
• Heart muscle


  • Asymmetrical as a result of the distance blood must travel in the pulmonary and systemic circuits
  • Right side is smaller than the left side
• Heart


  About the size of a clenched fist, divided into four chambers: two atria and two ventricles
• Atria


  Chambers that receive blood
• Ventricles


  Chambers that pump blood
• Blood flow through the right side of the heart

  1. Right atrium receives deoxygenated blood from the superior and inferior vena cava and coronary sinus

  2. Passes to the right ventricle through the tricuspid valve

  3. Right ventricle pumps blood through the pulmonary arteries and semilunar valve to the lungs
• Blood flow through the left side of the heart

  1. Left atrium receives oxygenated blood from the lungs via the pulmonary veins

  2. Passes through the mitral valve to the left ventricle

  3. Left ventricle pumps blood out through the aorta and aortic valve to the body
• This pattern of pumping is referred to as double circulation and is found in all mammals
• Heart layers


  • Epicardium (outer layer)
  • Myocardium (middle muscle layer)
  • Endocardium (inner lining)
• Pericardium


  Membranous layered structure that surrounds and protects the heart
• Coronary circulation


  1. Coronary arteries branch from the aorta and surround the heart

  2. Diverge into capillaries to supply the heart muscle with oxygen

  3. Converge into coronary veins to take deoxygenated blood back to the right atrium
• The heart muscle will die without a steady supply of blood
• Atherosclerosis


  Blockage of an artery by the buildup of fatty plaques
• Atherosclerosis in the coronary arteries

  Can be deadly due to the size and function of these arteries in serving the heart
• Angina

  Severe pain caused by the slowdown of blood flow and oxygen deprivation from atherosclerosis
• Myocardial infarction


  Death of cardiac muscle tissue, commonly known as a heart attack
• The heart is primarily made of a thick muscle layer, called the myocardium, surrounded by membranes. One-way valves separate the four chambers.
• Blood vessels of the coronary system, including the coronary arteries and veins, keep the heart musculature oxygenated.
• Cardiac cycle


  The coordination of the filling and emptying of the heart of blood by electrical signals that cause the heart muscles to contract and relax
• The human heart beats over 100,000 times per day
• Cardiac cycle


  1. Heart contracts (systole), pushing out blood

  2. Heart relaxes (diastole), filling with blood

  3. Atria contract, forcing blood through the atrioventricular valves into the ventricles

  4. Closing of the atrioventricular valves produces a "lup" sound

  5. Ventricles contract, forcing blood through the semilunar valves

  6. Closing of the semilunar valves produces a "dup" sound
• Respiratory system


  The system that brings oxygen into the body and removes carbon dioxide
• Breathing


  The process that brings oxygen in the air into your lungs and moves oxygen through your body
• Sinuses


  • Hollow spaces in the bones of the head that help regulate temperature and humidity of air, lighten the bone structure, and give tone to the voice
• Nasal cavity


  The best entrance for outside air into the respiratory system, with hairs that are part of the air-cleansing system
• Oral cavity


  Can also be an entrance for air, especially if nasal passages are blocked
• Adenoids


  Overgrown lymph tissues at the top of the throat that can interfere with breathing
• Lymph system

  Carries fluid throughout the body and helps resist infection
• Tonsils


  Lymph nodes in the wall of the pharynx that are not an important part of the germ-fighting system
• Pharynx


  Collects incoming air from the nose and passes it downward to the trachea
• Epiglottis


  Flap of tissue that guards the entrance to the trachea and closes when swallowing
• Larynx


  Contains the vocal cords that create voice sounds