L3 - Circulatory System

• circulatory system

  • responsible for transporting throughout the body oxygenated blood from the heart and lungs via the arteries
  • delivers the oxygen and nutrients to all cells in the human body
  • it transports carbon dioxide and other wastes to other areas of body and away from the cells
  • it helps in the coagulation process, regulates body temperature, and assists the body in fighting diseases
• Components of Circulatory System

  Cardiovascular

  • composed of heart, blood vessels, and blood
  • it helps in the circulation process
• Components of Circulatory System

  Lymphatic

  • made up of lymph, lymph nodes and vessels
• Heart - a hollow muscular organ that has four chambers (left and right atrium and ventricle) and is surrounded by a thin, fluid-filled sad called pericardium
• a human heart is about the same size as that of a person's clenched fist
• Layers of the Heart

  Epicardium

  • thin, watery membrane on the outer layer of the heart
  • covers the heart and is attached to pericardium
• Layers of the Heart

  Myocardium

  • thick layer of cardiac muscle in the middle layer of the heart
  • pumps blood into the arteries by contracting
• Layers of the Heart

  Endocardium

  • thin layer of epithelial cells in the inner layer of the heart
  • lines the valves and interior chambers
• interatrial septum - partition that separates the right from the left atria
• interventricular septum - separates the right and the left ventricles
• the coronary circulation supplies the blood as well provides drainage to the tissues and is composed of the left and right coronary arteries and coronary veins
• poor circulation could lead to ischemia which is caused by inadequate supply of oxygen and myocardial infarction or heart attack which may be due to complete obstruction of the coronary artery
• cardiac cycle - systole (contraction) and diastole (relaxation) which lasts about 0.8 seconds
• electrical conduction system - sends electric impulses throughout the myocardium which is initiated by the sinoatrial (SA) node (pacemaker)
• electrocardiogram - provides the graphical representation of the cardiac cycle's activity
• origin of heart sounds - "lubb" which is the first sound as the ventricles contract or the AV valves close and "dupp" or the second sound which is heard when the semilunar valves close and the ventricles relax
• heart rate and cardiac output - the average heart rate is 72 beats per minute and the cardiac output refers to the volume of blood pumped per minute
• pulse - a rhythmic throbbing resulting from the alternating expansion and contraction of the artery
• blood pressure - the force exerted by the blood on the walls of the vessel measured by the sphygmomanometer ; the difference between the systolic and diastolic
• angina pectoris - chest pain resulting from reduced blood flow to the heart
• aortic stenosis - a murmuring sound produced when the aortic leaflets fail to fully open during systole
• bacterial endocarditis - an infection that happens when a bacteria enters and resides in the heart lining or blood vessel
• congestive heart failure - a chronic progressive condition that affects the pumping power of the heart muscles
• myocardial infarction - known as heart attack that is caused by a decrease or full stoppage of blood flow that damages the heart muscle
• pericarditis - inflammation of the pericardial sac that may be due to viral infection
• vascular system - the loop consisting of a network of blood vessels through which blood is circulated to the rest of the body
• Main Division of Vascular System

  Pulmonary Circulation

  • moves the blood between the right ventricle of the heart to the lungs
  • during the process, oxygen is absorbed and carbon dioxide is released
  • the oxygenated blood flows back to the left atrium of the heart
• Main Division of Vascular System

  Systemic Circulation

  • moves the oxygenated blood and nutrients from the left ventricle of the heart to the rest of the body
  • the deoxygenated blood with carbon dioxide and wastes flows back to the right atrium
• arteries - thick-walled blood vessels that carry oxygen-rich blood from the heart to the tissues of the body
• arterioles - small-diameter blood vessels that branch out from the arteries and lead to the capillaries
• veins - tubes with thin walls that carry deoxygenated blood from tissues to the heart
• venules - very small veins that collect blood from the capillaries
• capillaries - fine hair-like blood vessels that connect arterioles and veins
• Blood Vessel Layers

  Tunica adventitia - outer connective tissue

  Tunica media - middle, muscle and elastic fiber

  Tunica intima - inner, endothelial cell
• Lumen - space inside the blood vessel where the blood flows
• valves - found in the veins, these are thin membranous leaflets that prevent the backflow of blood
• aneurysm - enlargement of the artery due to the weakening of the artery wall
• arteriosclerosis - hardening of the artery wall due to aging
• atherosclerosis - formation of plaques (fat) in the inner walls
• embolism - clot or bubble that causes obstruction of an artery