Ch. 13 Notes (The Cardiovascular System)
Functions of the Cardiovascular System
· Brings blood containing _______________, __________________, and ___________________ to cells
· Transports _______ and other wastes away from cells
· Fights infection
· Regulates body temperature
· Helps stabilize ______ and ______________________________ of body fluids.
Components
· Heart
· Blood
· Vessels: __________________________________________________
The Heart
· Is a muscular pump that moves blood through the body
· Is suspended in the _______________________
· Composed of four chambers
· Divided into right and left halves
· Made up of __________________ muscle cells
Layers of the Heart
· _____________________ – protective sac of connective tissue that surrounds the heart and filled with fluid
· _____________________ (outer) – (visceral pericardium) connective tissue that protects the heart from friction
· _____________________ (middle)
o The muscle of the heart
o Strong and thick
o Composed of spontaneously contracting cardiac muscle fibers
o Can conduct electricity like nerves
o It’s blood supply comes from the _____________________
· _____________________ (inner) – consists of epithelium and connective tissue that contains many elastic and collagenous fibers
Structures of the Heart
Chambers
· ___________ – (2) upper chambers
o Thin walled
o Receive blood from veins
o Send blood to ventricles
· _____________________ – (2) lower chambers
o Thick walled
o Receive blood from atria
o Pump blood out through arteries
· __________________ – a wall that divides heart into right and left halves
· Valves
o Prevent backflow of blood
o Keep blood moving in one direction
o Located between the chambers
· ___________________________
o “Heart strings”
o Cord-like tendons
o Connect papillary muscles to tricuspid and mitral valves
o Prevent inversion of valve
· _____________________ – small muscles that anchor the cords
Cardiac Cycle
· Refers to all of the events from the beginning of one heart beat to the beginning of the next heart beat
· When cardiac muscle contracts it does so as a single unit, creating a heart beat
· One heartbeat - a cardiac cycle - consists of two parts called ___________________and ___________________
· Diastole is the period of time when the heart relaxes after contraction
· Oxygenated blood from the lungs fills the _____________________________
· Deoxygenated blood from other parts of the body fills the _______________________________
· At the end of the diastole, the atria contract, starting the Systole
· Heart Sounds
o Two normal heart sounds with each heart beat described as a…..
o “_________”- sound- due to closure of the atrioventricular valves (____________and______________)
o “_________”- sound- due to closure of the aortic valve and pulmonary valve
· Heart Rate - count of each heart beat
· On average, a heart beats _______ times a minute when at rest
· Usually it is calculated as number of contractions of heart (heart beats) in one minute and expressed as "beats per minute" (bpm).
· The pulse is the most straightforward way of measuring the heart rate
· Heart rate is controlled by _____________________________
· An ____________________________ abbreviated as EKG or ECG is a test that measures the electrical activity of the heartbeat or one cardiac cycle.
Cardiac Conduction System
· Includes:
· _____________________ , _____________________ , _____________________ , _____________________
· Sinoatrial Node (SA node)
o Located high on the right atrium.
o _____________________ of the heart.
o Causes the wave of contractions in the atria to send blood into the ventricles
· Atrioventricular Node (AV node)
o Located in the interatrial septum close to the tricuspid valve
o Carries the electrical impulse from the SA node to fiber bundles in the ventricles.
o This causes the ventricles to contract from the apex (bottom) up squeezing blood up and out
Cardiovascular Circuits
· _____________________ Circulation
o Pumps blood low in oxygen to the lungs to pick up oxygen and return to heart
· _____________________ Circulation
o Oxygenated blood is pumped to the body cells thru the aorta and other arteries
o Blood low in oxygen returns to the heart
· _____________________ Circulation
o The coronary circulation consists of the blood vessels that supply blood to, and remove blood from the heart muscle itself.
o The vessels that supply blood high in oxygen to the myocardium are known as coronary arteries.
Blood Vessels
· Form a closed circuit of tubes that carry blood throughout the body
· Laid end to end, the blood vessels in an average human body will stretch approximately 62,000 miles……2.5 times around the earth
· _____________________
o Receive blood from ventricles
o Take blood away from the heart
o Usually carry _____________________ blood
o Thickest vessel walls
o Withstand greater blood pressure
o Are very elastic
o Connect to capillaries
o _____________________ is the largest artery
· ________________________
o Transport blood away from capillaries
o Carry blood toward heart
o Take blood to atria
o Have valves
o Thinner vessel walls with less smooth muscles than arteries
o Can stretch a great deal
o Have larger diameters
o Usually carry _____________________ blood
o _____________________ is the largest vein
o The contraction of muscles compressing veins helps push blood up through the leg veins back to the heart. The valves allow the blood to flow towards the heart only
· ___________________________
o Smallest of blood vessels
o Only one cell thick (epithelial cell)
o Connect ___________________ to _____________________
o Bring oxygen and nutrients to cells
o Removes CO2, urea, and other wastes from cells
o Where blood is under low pressure and moving slowly
Blood Pressure
· Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels
· The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, venules, and veins
· Blood pressure is most commonly measured via a _______________________________ (blood pressure cuff)
· A person's pulse is the throbbing of their arteries as an effect of the pressure waves (heart beat)
· Pulse is used to denote the frequency of the heart beat
· Pulse is usually measured in _________________________________________.
· In most people, the pulse is an accurate measure of heart rate.
Circulatory System Disorders
Heart Disease
· Risk factors
· Older age
· Male gender
· Cigarette smoking
· High cholesterol
· Diabetes
· Stress
· Obesity
· Heredity
· Physical inactivity
· High blood pressure
Atherosclerosis
· Starts with damage or injury to the inner layer of an artery
· Fatty deposits called plaque build up in the arteries
· This causes:
· Blockage in artery
· Less flexible vessels
· High Blood Pressure
Hypertension (High Blood Pressure)
· Makes the heart and blood vessels work harder
· Increases the chance of heart disease, heart attack or stroke
Heart Attack
· Acute myocardial infarction
· Interruption of oxygen supply to the heart
· Causes death of the heart muscle
· Leading cause of death in both men and women
· Symptoms
· Chest pain
· Squeezing or heavy pressure on chest
· Pain that radiates down left shoulder and arm
· Shortness of breath
· Nausea or vomiting
· Anxiety or Fainting
· Lightheadedness - dizziness
· Palpitations (feeling like your heart is beating too fast)
· Sweating, which may be extreme
Stroke
· Interruption of oxygen supply to the brain
· Caused by: A clot in an artery in the brain
· Breakage of an artery in the brain
· Causes brain cells to be deprived of oxygen and die
Thrombosis/Embolism
· Thrombosis is the formation of a clot (thrombus) inside a blood vessel, obstructing the flow of blood
· Embolism occurs when an object (usually a blood clot) migrates from one part of the body (through circulation) and causes a blockage (occlusion) of a blood vessel in another part of the body
Hemorrhage
· Hemorrhage is the medical term for bleeding - the loss of blood from the body
· Hemorrhage generally becomes dangerous, or even fatal, when it causes hypovolemia (low blood volume) or hypotension (low blood pressure).
Hemophilia
· A rare inherited bleeding disorder in which the blood does not clot normally
· The person is missing or has low levels of certain proteins in the blood called clotting factors
· Usually occurs only in males
· They suffer prolonged bleeding even with minor injuries
· Bleeding can occur internally, in joints and muscles, which causes swelling and pain
Anemia
· A condition where there is an abnormally low number of red blood cells circulating in the body or when the blood does not have enough hemoglobin
· The body's tissues are being starved of oxygen
· Most common disorder of the red blood cells, affecting (~) 3.5 million Americans
· There are different kinds of anemia
· Iron Deficiency
· Vitamin D eficiency
· Hemolytic Anemias
· Sickle Cell Anemia
· A person with anemia will feel tired, weak, breathless, and dizzy
· They may have a pale complexion, increased heart rate, low blood pressure, and difficulty concentrating
· The severity of the symptoms is related to the severity of anemia
Sickle Cell Disease
· Sickle cell trait- The person is carrying the defective gene, but also has some normal hemoglobin
Valve Disorders
· Valvular Regurgitation
· Valvular stenosis
· A condition in which there is a narrowing, stiffening, thickening, fusion or blockage of one or more valves of the heart.
Heart Murmur
· A whooshing sound between the heart beats
· The whoosh is an extra noise that blood makes as it flows through any of the heart's chambers or valves or even through a hole within the heart
· More than half of all children have a heart murmur at some time in their lives and most of these don't mean anything is wrong
· Innocent heart murmurs can occur when blood flows more rapidly through the heart - such as during physical activity or exercise, pregnancy, fever, anemia, from aging or even heart surgery
· Over time, innocent heart murmurs may disappear
· Abnormal heart murmurs are caused by structural defects in the heart…. congenital heart defects, valve abnormalities, or holes in the heart
· Some abnormal defects can be treated with medicines while others require surgical repair
Aneurysm
· Localized, blood-filled dilation (bulge) of a blood vessel caused by disease or weakening of the vessel wall
· Most commonly occur in arteries at the base of the brain and in the aorta
· Can burst and lead to death at any time