Circulatory System
Aortic Valve
Located between left ventricle and aorta, largest artery in the body Closes when left ventricle is finished contracting and pushing blood into aorta Prevents blood from flowing back into left ventricle
Tricuspid Valve
Located between right atrium and right ventricle Closes when right ventricle contracts and pushes blood to the lungs Prevents blood from flowing back into right atrium
Pulmonary Valve
Located between right ventricle and pulmonary artery, a blood vessel that carries blood to lungs Closes when right ventricle has finished contracting and pushing blood into pulmonary artery Prevents blood from flowing back into ventricle
Myocardium
Thickest layer Muscular middle layer
Path that blood takes
heart, artery, arteriole, capillary, venule, vein, heart
PHLEBITIS
inflammation of the walls of a vein
endocardium
inner lining of the heart Smooth layer of cells Lines inside of the heart and is continuous with the inside of blood vessels Allows for smooth flow of blood
HEMOPHILIA
nherited disease occurs almost exclusively in males but carried by females Most cases diagnosed by age 2 Often diagnosed during circumcision Blood not able to clot due to lack of plasma protein Minor cut can lead to prolonged bleeding Minor bump can cause internal bleeding Tx: life long disease with no cure Regular infusions of the deficient clotting factor can help control the bleeding
SA node
pacemaker of the heart
LEUKOCYTES
white blood cells 5 Types of Leukocytes: Neutrophils—remove toxins and defend body from allergic reactions by producing antihistamines Eosinophils—remove toxins and defend body from allergic reactions by producing antihistamines Basophils—participate in body's inflammatory response; produce histamine, a vasodilator, and heparin(anticoagulant) Monocytes—phagocytize bacteria and foreign body Lymphocytes—provide immunity for the body by developing antibodies; protect against formation of cancer cells
DIASTOLE
"dub" =S2 closing of the semilunar valves (pulmonary & aortic valves)
SYSTOLE
"lub" =S1 closing of the AV valves (mitral & tricuspid valves)
CIRCULATORY SYSTEM
AKA the cardiovascular system Consists of the heart, blood vessels, and blood Often referred to as the transportation system because it transports oxygen and nutrients to body cells and transports wastes away from the body cells
How many blood cells die every second?
About 8 million blood cells die in the human body every second, and the same number are born each second.
ARTERIES
Carry oxygenated blood away from the heart More muscular and elastic than other blood vessels because they receive blood as it is pumped from the heart Aorta Largest artery in the body receives blood from left ventricle of the heart Branches off into all other arteries that supply blood to the body Arterioles Smallest branches of arteries Join with capillaries
CAPILLARIES
Connect arterioles with venules Located in close proximity to almost every cell in the body Have thin walls that contain only one layer of cells Allow oxygen and nutrients to pass through to the cells At the same time, carbon dioxide and metabolic products from the cells enter the capillaries
Pericardium
Double-layered membrane or sac Covers outside of the heart Pericardial fluid fills space between 2 layers and prevents friction and damage to membranes as the heart beats, or contracts
cardiac cycle
At start of cycle, atrium contract and push blood into ventricles Then atrium relax Blood returning from the body enters right atrium While atria are filling, systole begins and ventricles contract Right ventricle pushes blood into pulmonary artery so it can go to the lungs for oxygen Left ventricle pushes blood into aorta so it can be carried to all parts of the body Blood in the right side of the heart is low in oxygen and high in carbon dioxide When it gets tot the lungs, carbon dioxide is released into lungs and oxygen is taken into blood Oxygenated blood is then carried to left side of heart by pulmonary veins Now blood in left side of heart is high in oxygen and low in carbon dioxide and ready to be carried to body cells
ANEURYSM
Ballooning out or saclike formation on wall of artery Causes: disease, high BP, congenital defects, injuries leading to a weakening structures of wall of artery Sx: some cause pain and pressure, some have no Sx at all If aneurysm ruptures, hemorrhage occurs, which can cause death Tx: risks of surgical repair are similar to risks of rupture, so watchful waiting approach with control of BP is often used Surgical plastic graft can be performed in severe cases
myocardial infarction (heart attack)
Blockage in the coronary arteries cuts off supply of blood to the heart Lack of blood flow can cause ischemia, tissue injury, or tissue death Acute coronary syndrome is a term used to identify patients who are suspected of having myocardial ischemia With myocardial infarction, death can occur immediately if large area is affected Sx: severe crushing pain that radiates to arm neck, and jaw Pressure in the chest Perspiration and cold, clammy skin Dyspnea A sense of doom Change in blood pressure
HYPERTENSION
High BP Systolic pressure above 140 to 150mm Diastolic pressure above 90 mm Risk factors that increase incidence Family Hx Race: higher in African Americans Obesity Stress Smoking Aging: high in postmenopausal women Diet high in saturated fat
BLOOD COMPOSITION
Blood is often called a tissue because it contains many kinds of cells About 4-6 quarts of blood in the average adult Blood circulates throughout the body continually Transports many substances Oxygen from the lungs to body Carbon dioxide from body to lungs Nutrients from digestive tract to cells Metabolic waste products from cells to organs of excretion Heat produced by various body parts Hormones produced by endocrine glands to organs in the body
BLOOD VESSELS
Blood leaving the heart is carried throughout the body in blood vessels Heart and blood vessels form a closed system for flow of blood 3 main types of blood vessels: arteries, veins, and capillaries
VEINS
Blood vessels that carry blood away from the body to the heart Veins are thinner that arteries and have less muscle tissue Superior and Inferior Vena Cava Two largest veins that drain into the right atrium Venules Smallest branches of veins that connect with capillaries
ATHEROSCLEROSIS
Fatty plaques, frequently cholesterol, deposited on wall of arteries Lack of blood flow to the heart, brain, or extremities can cause a heart attack, stroke or gangrene If plaques break loose, they can circulate through blood stream as emboli Tx: low-cholesterol diet, medications to lower BP and cholesterol blood levels, abstaining from smoking, reduction of stress, and exercise Surgeries to open clogged arteries Balloon angioplasty Coronary atherectomy Coronary stent Bypass surgery when arteries are completely blocked
PLASMA
Fluid or liquid portion of blood Consists of about 90% H2O Many substances are dissolved or suspended in the water Blood proteins such as fibrinogen and prothrombin, necessary for clotting Nutrients such as vitamins, carbs, and proteins Mineral salts or electrolytes such a sodium, potassium, and calcium Gases such as carbon dioxide and oxygen Metabolic and waste products Hormones Enzymes
EMBOLUS
Foreign substance circulating in blood stream Can be air, blood clot, bacterial clumps, fat globule Blockage of vessel occurs when embolus enters an artery or a capillary too small for passage
ARTERIOSCLEROSIS
Hardening or thickening of arterial walls Causes loss of elasticity and contractility Commonly occurs as result of aging Causes hypertension and can lead to aneurysm or cerebral hemorrhage Main focus of Tx is lowering blood pressure through the use of diet and/or medications
CONGESTIVE HEART FAILURE
Heart muscles do not beat adequately to supply blood needs to the body May involve right or left sides of the heart Risk factors include high BP, high cholesterol, obesity and diabetes Sx: edema, dyspnea, pallor or cyanosis, distention of the neck veins, weak and rapid pulse, cough with pink frothy sputum Tx: Cardiotonic drugs to slow and strengthen heartbeat Diuretics to remove fluid Elastic support hose to improve circulation Oxygen therapy Weight loss/ low-sodium diet Exercise
ANEMIA
Inadequate number of erythrocytes hemoglobin, or both Hemoglobin carries O2 tissues and organs Decrease in hemoglobin can cause hypoxia, a lack of oxygen supply Sx: paleness, fatigue, dyspnea, rapid HR
How long does it take a blood cell to circle the whole body?
It takes about 20 seconds for a red blood cell to circle the whole body.
bicuspid valve
Located between left atrium and left ventricle Closes when left ventricle is contracting and pushing blood into aorta so blood can be carried to the body Prevents blood from flowing back into left atrium
LEUKEMIA
Malignant disease(cancer) of bone marrow or lymph tissue Results in large number of immature or abnormal white blood cells that do not function properly to fight infection Different types of leukemia: some acute, some chronic, some common in children while others more prominent in adults Sx: fever, frequent infections, pallor, swelling of lymphoid tissues, persistent fatigue, anemia, bleeding gums, excessive bruising, joint pain Tx: Varies with type of Leukemia Can include chemotherapy, radiation and stem cell or bone marrow transplants
THE HEART
Muscular hollow organ Often called the pump of the body Weighs less than 1 pound About the size of your fist Contracts about 100, 000x each day to pump the equivalent of 2,000 gallons of blood through the body Located between the lungs
THE SEPTUM
Muscular wall Separates heart into a right & left sides Upper part of the septum called the interatrial septum Lower part called the interventricular septum
Cardiac arrhythmia
Premature atrial contraction(PAC), an early contraction of the atria, can occur in anyone and usually goes unnoticed Ventricular fibrillation, in which ventricles contract at random without coordination, decreases or eliminates blood output and causes death if not treated TX: External or internal artificial pacemakers Small battery-powered device with electrodes Electrodes are threaded through a vein and positioned in R atrium and apex of R ventricle Pacemakers monitors heart's activity and delivers electrical impulse through electrodes to stimulate contraction Fixed pacemakers deliver electrical impulses at predetermined rate Demand pacemakers, the most common type, deliver electrical impulses only when the heart's own conduction system is not responding correctly
How many trips do red blood cells make around the body?
Red blood cells make approximately 250,000 round trips of the body before returning to the bone marrow, where they were born, to die.
How long do red blood cells live?
Red blood cells may live for about 4 months circulating throughout the body, feeding the 60 trillion other body cells.
Blood clot
When a blood vessel is cut, thrombocytes collect at the site to form a sticky plug They secrete a chemical, serotonin, which causes the blood vessel to spasm and narrow, decreasing the flow of blood Also release an enzyme, thromboplastin, which acts with calcium and other substances in the plasma to form thrombin Thrombin acts on the blood protein fibrinogen to form fibrin, a gel-like net of fine fibers that traps erythrocytes, platelets, and plasma to form a clot Effective method for controlling bleeding in smaller blood vessels If a large blood vessel is cut, the rapid flow of blood can interfere with the formation of fibrin Doctor may have to insert sutures to close the opening and control bleeding
How many red blood cells are in a drop of blood?
Within a tiny droplet of blood, there are some 5 million red blood cells.
varicose veins
abnormally swollen, twisted veins with defective valves; most often seen in the legs
THROMBOCYTES
platelets Usually described as fragments or pieces of cells Do not have a nucleus Vary in shape and size Formed in bone marrow and live about 5-9 days Important for the clotting process which stops bleeding
AV bundle (bundle of His)
fibers in the heart that relay a nerve impulse from the AV node to the ventricles
Purkinje fibers
fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract
Right Atrium
receives blood as it returns from the body
Right Ventricle
receives blood from right atrium and pushes blood into the pulmonary artery, which carries the blood to the lungs for oxygen
Left Ventricle
receives blood from the left atrium and pushes blood into the aorta so it can be carried to the body
Left Atrium
receives oxygenated blood from the lungs
ERYTHROCYTES
red blood cells Contains a complex protein called hemoglobin Composed of a protein molecule called globin and an iron compound called heme Carries both oxygen and carbon dioxide When hemoglobin carries oxygen, it gives blood its characteristic red color When there is less oxygen and more CO2, blood is a much darker red
AV node
relays electrical impulses from atria into ventricles
Blood doping
the practice of boosting the number of red blood cells in the bloodstream in order to enhance athletic performance. Because such blood cells carry oxygen from the lungs to the muscles, a higher concentration in the blood can improve an athlete's aerobic capacity (VO2 max) and endurance Because it improves stamina, athletes in extended time competitions(biking, running) may practice blood doping via Blood transfusions EPO injections Injections of synthetic oxygen carriers Banned by the Olympic Committee
