Phlebotomy Chapter 6 Review
Layers of heart
Epicardium: thin outer layer ▪ Myocardium: middle muscle layer ▪ Endocardium: thin inner layer
Blood type
Inherited o Determined by presence or absence of antigens on surface of red blood cells o A person's blood either contains or has the ability to develop antibodies directed at the opposite blood type
Intrinsic
Inside bloodstream ▪ Produces thrombin on the surface of activated platelets
Lumen
Internal space of a blood vessel, through which blood flows
Electrical conduction system
Specialized cells that initiate & distribute electrical impulses throughout the myocardium to coordinate cardiac cycle
tunica media
middle; smooth muscle & elastic fibers
pulmonaries take
deoxygenated blood to the lungs and to the veins
Thrombocytes (platelets):
essential to coagulation
Hemostasis
o Arrest or stoppage of bleeding after injury as a body response o Requires coordinated interaction of endothelial cells lining blood vessels, platelets, other blood cells, plasma proteins, & clotting o Is ongoing daily, in conjunction with vessel repair
Lymph
excess tissue fluid that filters into lymphatic capillaries
M-Shaped pattern of antecubital veins
o Cephalic vein o Median vein ▪ First choice o Median cephalic vein ▪ Second choice o Median basilic vein ▪ Third choice o Basilic vein
In Vivo/Cell-Based Coagulation
o Initiation o Amplification o Propagation
structure of lymphatic system
o Lymph (fluid) o Lymphatic vessels, ducts, & nodes
two ducts empty into large veins in upper body
o Lymph is moved by skeletal muscle contraction o Lymph passes through lymph nodes that filter out impurities
H-shapes pattern of antecubital veins
o Median cubital vein ▪ Located near center of AC ▪ Preferred vein/first choice o Cephalic vein ▪ Located in the lateral aspect of AC ▪ Second choice o Basilic vein ▪ Located in the medial aspect of AC ▪ Last choice o Displayed by approximately 70% of population
lymphatic system functions
o Returns tissue fluid to bloodstream o Protects body by removing microorganisms & impurities o Processes lymphocytes o Delivers fats absorbed from small intestine to bloodstream
The Role of the Liver in Hemostasis
o Synthesizes many coagulation factors: V, VIII, prothrombin, & fibrinogen o Produces bile salts needed for synthesis of some factors o Produces heparin
pulmonary
pertaining to the lungs
Which formed element is the first to play a role in sealing an injury to a blood vessel?
platelet
Cardiac output
volume of blood pumped by heart in 1 minute.
Secondary hemostatic plug formation
▪ Amplification ▪ Propagation
Rh blood group system
▪ Based on the "D" antigen (also called Rh factor) ▪ Rh positive (Rh+): RBCs have the D antigen ▪ Rh negative (Rh-): RBCs lack the D antigen
plasma
▪ Contains fibrinogen ▪ Specimen must be collected in an anticoagulant tube ▪ Used in cases when serum cannot be used ▪ Fluid portion of whole blood separated from the RBCs, WBCs, & platelets by centrifugation
serum
▪ Fluid portion of blood remaining after clotting ▪ Can be separated from clot by centrifugation ▪ Does not contain fibrinogen (used up in clotting)
Septa: partitions separating right & left sides of heart
▪ Interatrial ▪ Interventricular
Capillaries
▪ Microscopic, one-cell--thick vessels that connect arterioles & veins ▪ Site of gas exchange between blood & body tissues
Cardiac cycle
▪ One complete contraction (systole) & relaxation (diastole) of heart ▪ Lasts about 0.8 seconds
Fibrinolysis
▪ Process by which fibrin is dissolved ▪ Ongoing process: ➢ Dissolves clots that form in intact vessels, reopening them ➢ Removes hemostatic clots from tissue as healing occurs
Vasoconstriction
▪ Reduction in diameter of blood vessel ▪ Caused by contraction of smooth muscle fibers in vessel ▪ Decreases blood flow past injured area & limits blood loss
Capillaries join to form larger vessels that empty into terminal vessels:
▪ Right lymphatic duct ▪ Thoracic duct
ABO blood group system
▪ Two antigens (A & B) ▪ Four blood types (A, B, AB, & O)
Leukocytes (white blood cells)
➢Formed in bone marrow & lymphatic tissue ➢Neutralize or destroy pathogens ➢Types: granulocytes & agranulocytes
Erythrocytes (red blood cells)
➢Most numerous cells in body ➢ Carry O2 & CO2 ➢ Produced in bone marrow
Coagulation Pathways
extrinsic and intrinsic
Main components of the cardiovascular system
heart, blood vessels, blood
tunica externa
inner; single layer endothelial cells, basement membrane, connective tissue, & elastic internal membrane
aorta
largest artery
The basilic vein is the last choice for venipuncture because it is:
located near a major nerve
Main components of the lymphatic system
lymph, lymph vessels, lymph node
Two commonly used blood group systems
ABO blood group system Rh blood group system
veins
Return deoxygenated blood from tissues to heart ▪ Thin walls, low pressure
Antecubital fossa
Shallow depression in arm anterior to & below bend of elbow ▪ Site of major veins, & thus first choice for venipuncture
size and surrounding of heart
Size of a man's fist Surrounded by pericardium (thin, fluid-filled sac)
arteries always take blood
away from the heart
Second heart sound
"dupp" (ventricles relax, semilunar valves close)
Describe the first heart sound
"lubb" (ventricles contract, AV valves close)
Coronary circulation
: flow of blood through arteries and veins within the heart muscle, also called cardiac circulation
Heart Attack components
-Myocardial ischemia: partial obstruction of coronary artery OR ➢Myocardial infarction: complete obstruction or prolonged ischemia
Functions of the circulatory system
1. Transport to cells 2. Protection away from cells 3. Regulation aids in coagulation and defense
Process of hemostasis
1. Vasoconstriction 2. Formation of a primary platelet plug 3. Progression to a stable blood clot 4. Fibrinolysis (dissolving of clot)
Separated whole-blood specimen
55 liquid to 45 blood
The normal composition of blood is approximately
55% plasma, 45% formed elements
How large is a normal erythrocyte
7-8 microns
average heart rate
72 beats per minute
Plasma
90% water ▪ Gases (O2, CO2, N) ▪ Minerals (Na, K, Ca, Mg) ▪ Carbs & lipids ▪ Proteins ▪ Waste products ▪ Vitamins, hormones, drugs
Diastolic
: arterial pressure during relaxation of ventricles
Electrocardiogram (ECG)
A graphic record of heart's electrical activity during cardiac cycle
Chambers of the heart
Atria, right & left ▪ Ventricles, right & left
Valves of the heart
Atrioventricular (AV), right (tricuspid) & left (bicuspid) ▪ Semilunar, right (pulmonary) & left (aortic)
whole blood
Blood in the same form as it is in the bloodstream ▪ Not allowed to clot or separate ▪ Specimen must be collected in an anticoagulant tube ▪ Must be mixed a minimum of 2 minutes just prior to test
Pulmonary circulation
Carries blood from right ventricle of heart to lungs ▪ Carbon dioxide is removed; oxygen is picked up ▪ Oxygenated blood returns to left atrium of heart
Systemic circulation
Carries oxygenated blood & nutrients from left ventricle to body cells ▪ Returns deoxygenated blood with carbon dioxide & wastes from cells to right atrium
Arteries
Carry oxygenated blood away from heart to tissues ▪ Thick walls to withstand high pressure
diagnostic tests for vascular system
Diagnostic Tests o DIC screen o Lipoproteins o Prothrombin time o Partial thromboplastin time o Triglycerides
Structure of the heart
Four-chambered, hollow, muscular organ
Leg, ankle, and foot veins
High risk for phlebitis or thrombosis, only used with physician permission
Arm and leg arteries
Not routinely used for blood collection
Extrinsic
Outside bloodstream ▪ Initiates the coagulation process
pulse of the heart
Palpable rhythmic throbbing caused by alternating expansion & contraction of an artery as blood passes through
Bicipital aponeurosis
The median vein and the lateral aspect of the median cubital vein overlie this fibrous membrane ▪ An attempt should be made to locate one of these veins on either arm before an alternate AC vein is considered
valves
Thin, membranous leaflets in veins prevent backflow of blood
Dorsal forearm, hand, and wrist veins
Veins on lateral wrist above thumb to mid-forearm must not be used due to risk of nerve injury
Blood transfusion of the wrong type can
agglutinate and hemolyze red blood cells (transfusion reaction)
veins always take blood
back to the heart
aorta goes to
body
Atherosclerosis
buildup of plaque causing narrowing of coronary arteries and reduced blood flow to the heart
Angina (pectoris)
chest pain due to reduced blood flow to the heart
vein blood is moved by
skeletal muscle movement, valves that prevent backflow, & pressure changes in cavities in breathing
Arterioles
small branches of arteries that join capillaries
Venules
small veins that join capillaries
puloamr
take oxygen blood
which part initiates electrical impulse
the Sinoatrial (SA) node (pacemaker)
tunica intima
the innermost layer of a blood vessel
systolic blood pressure
the pressure created in the arteries when the left ventricle contracts and forces blood out into circulation
Which is the medical term for a blood clot circulating in the bloodstream?
thrombus
Layers of blood vessels
tunica intima, tunica media, tunica externa
The greatest chance of nerve injury is
venipuncture in the most medial and lateral portions of the antecubital fossa.
