Day 9: The Circulatory System
Overview of the circulatory system
-Carries oxygen and food to the cells of the body
Carries carbon dioxide and other waste away from cells to excretory organs, kidney, lungs and skin
Aids in coagulation process
Assists in defending body against disease
And in regulation of body temperature
The circulatory system is a system of closed tubes. Circulation occurs in two large loops- the pulmonary circulation and the systemic circulation. The pulmonary circulation carries blood between the heart and the lungs for gas exchange, and the systemic circulation carries blood between the heart and the rest of the body's tissues. In both cases, arteries carry blood from the heart to capillary beds, where exchange occurs. Veins return blood to the heart.
Atria, right and left
Ventricles, right and left
Septa: partitions separating the right and left sides of the heart
One complete contraction (systole ) and relaxation ( diastole ) of the heart
Last about 0.8 seconds
Carries blood from right ventricle of heart to lungs
Carbon dioxide is removed: oxygen is picked up
Oxygenated blood returns to the left atrium of the heart
Carries oxygenated blood and nutrients from left ventricle to body cells
Returns deoxygenated blood with carbon dioxide and wastes from cells to right atrium
-Origin of the heart sounds
The first sound: “LUBB” (ventricles contract, AV valves close )
The second sound: “DUPP” ( ventricles relax, semilunar valves close )
Heart rate: number of heartbeats per minute
Cardiac output: volume of blood pumped by the heart in one minute
Pulse: palpable rhythmic dropping caused by alternating expansion and contraction of an artery as blood passes through
Blood pressure: force exerted by blood on the walls of vessels
Carry oxygenated blood away from the heart to issue
Thick walls to withstand high pressure
Aorta is the largest artery
Return deoxygenated blood from tissue to heart
Thin walls, low pressure
Blood is moved by skeletal muscles movement, valves that prevent back flow, & pressure changes in breathing
Microscopic, one-cell-thick vessels that connect arterioles & veins
Site of gas exchange between blood and body tissues
Blood vessels layers
Tunica Adventitia: outer, connective tissue
Tunica Media: Middle. Smooth muscles & elastic fibers
Tunica Intima: inner, Single layer endothelial cells, basement membrane, connective tissue & elastic internal membrance
Lumen: Internal space a blood vessel through which blood flows
Valves: thin membrane leaflets in veins prevents back flow of blood
Coronary artery diseases (CAD): Illness where the arteries that supply the heart muscle become narrowed, thickened, and hardened by the buildup of fatty deposit called plaque.
The plaque damages the inner lining of the vessel and causes hardening and thickening of the vessel wall. The name of this condition is atherosclerosis.
The major cause of coronary artery diseases is atherosclerosis (is the build-up of fat in the wall of the arteries).
As coronary artery diseases progress, the damaged to the coronary arteries can cause increase in the blood pressure and decreases blood flow to the heart muscle.
In extreme cases, a total blockage of the artery can result in heart muscle death (Heart Attack or Myocardial Infarction, MI).
Arteriosclerosis can also affect other arteries, including those in the brain and those that supply the arms and legs.
Coronary artery diseases can also cause complications if plaque becomes dislodged from the artery wall or if damage in the artery results in the formation of a blood clot.
Thrombus: blood clot that stays in the wall of the blood vessels.
Embolus: is when this thrombus dislodged from the wall of the blood vessel and goes into the blood flow.
Ischemia and Myocardial Infarction
When an embolus (Blood Clot) blocks the coronary artery, the heart muscle supplies by that vessel does not get enough oxygen, creating a condition called ischemia
Ischemia: pain cause by a lack of oxygen and blood
If ischemia in not treated, it may results in myocardial infarction (MI).
Myocardial infarction (MI) or heart attack:
Caused by complete block of blood flow to heart muscle, which results in tissue death.
Area of dead tissue may be large or small. Can result in serious heart damage or death.
Symptoms of a heart attack:
sudden severe pain in the chest, usually on the left side
skin color maybe pale or cyanotic (bluish)
anxiety- sense of doom
cold and clammy skin
skin that is pale, blue or gray, due to low levels of oxygen in the bloodstream
the medical term for chest pain, pressure, or discomfort due to coronary artery disease.