NAME: ______________________________________ DATE: ___________ BLOCK: _____
BLOOD
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The only fluid tissue in the human body
Classified as a connective tissue
– Living cells = formed elements
– Non-living matrix = plasma
Physical Characteristics of Blood
• Color range
– Oxygen-rich blood is scarlet red
– Oxygen-poor blood is dull red
• pH must remain between 7.35–7.45
• Blood temperature is slightly higher than body temperature
Blood Plasma
• Composed of approximately 90 percent water
• Includes many dissolved substances
– Nutrients
– Salts (metal ions)
– Respiratory gases
– Hormones
– Proteins
– _______________________ products
Plasma Proteins
• Albumin – regulates osmotic pressure
• Clotting proteins – help to _____________ blood loss when a blood vessel is injured
• Antibodies – help protect the body from antigens
Formed Elements
• Erythrocytes = ___________ blood cells
• Leukocytes = _______________ blood cells
• Platelets = cell fragments
Erythrocytes (Red Blood Cells)
• The main function is to _____________________________
• Contains hemoglobin
• Anatomy of circulating erythrocytes
– Biconcave disks
– Essentially bags of hemoglobin
– Anucleate (no nucleus)
– Contain very few organelles
• 4 - 6 million per mm3 of blood
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Hemoglobin
• ________________-containing protein
• Binds strongly, but reversibly, to ______________________
• Each hemoglobin molecule has four oxygen binding sites
• Each erythrocyte has 250 million hemoglobin molecules
Homeostatic Imbalance
• Anemia – _________________________ in oxygen-carrying ability of blood
• May be caused by:
– Low red blood cell count (RBC)
– Abnormal or deficient hemoglobin
– Lack of B12 or intrinsic factor
– Lack of iron
– Cancer
• Sickle cell anemia – genetically defective hemoglobin
• Polycythemia – abnormal increase in RBC
– May be from bone marrow cancer or living at high altitudes
– Causes increased viscosity of blood
Leukocytes (White Blood Cells)
• Crucial in the body’s _________________________ against disease
• These are complete cells, with a nucleus and organelles
• Able to move into and out of blood vessels (diapedesis)
• Can move by ameboid motion
• Can respond to chemicals released by damaged tissues
Leukocyte Levels in the Blood
• Normal levels are between 4,000 and 11,000 cells per mm 3
• Abnormal leukocyte levels
– Leukocytosis
• Above 11,000 leukocytes/ml
• Generally indicates an infection
• Could indicate _____________________ (WBC cancer)
– Leukopenia
• Abnormally low leukocyte level
• Commonly caused by certain drugs
Platelets
• Derived from ruptured cells
• Needed for the ___________________________ process
• Normal platelet count is 250,000 - 500,000/mm3
Hematopoiesis
• Blood ________ formation
• Occurs in ________________________________________
• All blood cells are derived from a common stem cell (hemocytoblast)
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Hemocytoblast differentiation
– Lymphoid stem cell produces lymphocytes
– Myeloid stem cell produces other formed elements
Fate of Erythrocytes
• Unable to divide, grow, or synthesize proteins
• Wear out in 100 to 120 days
• When worn out, are eliminated by phagocytes in the _________________ or liver
• Lost cells are replaced by division of hemocytoblasts
Control of Erythrocyte Production
• Rate is controlled by a hormone (_______________________________)
• Kidneys produce most erythropoietin as a response to reduced oxygen levels in the
blood
• Homeostasis is maintained by negative feedback from blood oxygen levels
Hemostasis
• Stoppage of blood flow
• Result of a break in a blood vessel
• Hemostasis involves three phases
– Platelet plug formation
– Vascular spasms
– Coagulation
Platelet Plug Formation
• Collagen fibers are exposed by a break in a blood vessel
• Platelets become “__________________” and cling to fibers
• Anchored platelets release chemicals to attract more platelets
• Platelets pile up to form a platelet plug
Vascular Spasms
• Anchored platelets release serotonin
• ________________________________ causes blood vessel muscles to spasm
• Spasms narrow the blood vessel, decreasing blood loss
Coagulation
• Injured tissues release thromboplastin
• PF3 (a phospholipid) interacts with thromboplastin, blood protein clotting factors, and
calcium ions to trigger a clotting cascade
• Prothrombin activator converts prothrombin to ______________________________ (an
enzyme)
• Thrombin joins fibrinogen proteins into hair-like fibrin
• Fibrin forms a meshwork (the basis for a clot)
Blood Clotting
• Blood usually clots within 3 to 6 minutes
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The clot remains as endothelium regenerates
The clot is broken down after tissue repair
Undesirable Clotting
• _________________
– A clot in an unbroken blood vessel
– Can be deadly in areas like the heart
• _________________
– A thrombus that breaks away and floats freely in the bloodstream
– Can later clog vessels in critical areas such as the brain
Bleeding Disorders
• Thrombocytopenia
– Platelet deficiency
– Even normal movements can cause bleeding from small blood vessels that
require platelets for clotting
• Hemophilia
– Hereditary bleeding disorder
– Normal clotting factors are missing
Blood Groups and Transfusions
• Large losses of blood have serious consequences
– Loss of 15 to 30 percent causes weakness
– Loss of over 30 percent causes shock, which can be fatal
• Transfusions are the only way to replace blood quickly
• Transfused blood must be of the same blood group
Human Blood Groups
• Blood contains genetically determined proteins
• A foreign protein (antigen) may be attacked by the immune system
• Blood is “typed” by using antibodies that will cause blood with certain proteins to clump
(agglutination)
• There are over 30 common red blood cell antigens
• The most vigorous transfusion reactions are caused by ABO and Rh blood group
antigens
ABO Blood Groups
• Based on the presence or absence of two antigens
– Type ____ (only A antigen)
– Type ____ (only B antigen)
– Type AB (both A and B antigen)
– Type O (neither A or B)
Rh Blood Groups
• Named because of the presence or absence of one of eight Rh antigens
• Most Americans are ______________
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Problems can occur in mixing Rh+ blood into a body with Rh– blood
Rh Dangers During Pregnancy
• Danger is only when the mother is Rh– and the father is Rh+, and the child inherits the
Rh+ factor
• The mismatch of an Rh– mother carrying an Rh+ baby can cause problems for the
unborn child
– The first pregnancy usually proceeds without problems
– The immune system is sensitized after the first pregnancy
– In a second pregnancy, the mother’s immune system produces antibodies to
attack the Rh+ blood (hemolytic disease of the newborn)
Developmental Aspects of Blood
• Sites of blood cell formation
– The fetal liver and spleen are early sites of blood cell formation
– Bone marrow takes over hematopoiesis by the seventh month
• Fetal hemoglobin differs from hemoglobin produced after birth
CARDIOVASCULAR SYSTEM
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A closed system of the heart and blood vessels
– The heart pumps blood
– Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver ________________ and
nutrients and to remove ___________________ and other waste products
The Heart
• Location
– Thorax between the lungs
– Pointed apex directed toward left hip
• About the size of your fist
The Heart: Coverings
• ___________________________ – a double serous membrane
– Visceral pericardium
• Next to heart
– Parietal pericardium
• Outside layer
• Serous fluid fills the space between the layers of pericardium
• Pericarditis – inflammation of pericardium, which causes a decrease in serous fluid
The Heart: Heart Wall
• Three layers
– Epicardium
• Outside layer
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• This layer is the parietal pericardium
• Connective tissue layer
– _______________________________
• Middle layer
• Mostly cardiac muscle
– Endocardium
• Inner layer
• Endothelium
The Heart: Chambers
• Right and left side act as separate pumps
• Four chambers
– _______________________
• Receiving chambers
– Right atrium
– Left atrium
– _______________________
• Discharging chambers
– Right ventricle
– Left ventricle
The Heart: Valves
• Allow blood to flow in only one direction
• Four valves
– Atrioventricular valves – between atria and ventricles
• ___________________ valve or _______________ (left)
• ___________________ (right)
– Semilunar valves between ventricle and artery
• Pulmonary semilunar valve
• Aortic semilunar valve
• Valves open as blood is pumped through
• Held in place by chordae tendineae (“heart strings”)
• Close to prevent backflow
The Heart: Associated Great Vessels
• Aorta
– Leaves left ventricle
• Pulmonary arteries
– Leave right ventricle
• Vena cava
– Enters right atrium
• Pulmonary veins (four)
– Enter left atrium
Coronary Circulation
• Blood in the heart chambers does not nourish the myocardium
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The heart has its own nourishing circulatory system
– ___________________ arteries
– Cardiac veins
– Blood empties into the right atrium via the coronary sinus
Homeostatic Imbalance
• Valvular stenosis – valve flaps become stiff, often from endocarditis (bacterial infection
of endocardium)
• Faulty valves may be replaced by synthetic or pig valves
• Angina pectoris – chest pain as a result of the myocardium being deprived of oxygen
• _______________________________ (heart attack) – prolonged angina that kills
heart cells
The Heart: Conduction System
• Intrinsic conduction system
(nodal system)
– Heart muscle cells contract, without nerve impulses, in a regular and continuous
way
• Special tissue sets the pace
• ___________________ or pacemaker
– In right atrium
– Starts impulse
• Atrioventricular node
– At junction of right atrium and ventricle
• Atrioventricular bundle
– In interventricular septum
• Bundle branches
• ____________________________
– In wall of ventricles
Homeostatic Imbalance
• Heart block – damage to AV node causing ventricular contraction to beat at own rate
(much slower)
• Ischemia – lack of adequate blood supply to heart muscle
• Fibrillation – rapid uncoordinated shuddering of heart muscle (caused by ischemia)
• Tachycardia – rapid heart rate (over 100 bpm)
• Brachycardia – much slower rate (under 60 bpm)
The Heart: Cardiac Cycle
• Atria contract simultaneously
• Atria relax, then ventricles contract
• ___________________ = contraction
• ___________________ = relaxation
• Cardiac cycle – events of one complete heart beat
– Mid-to-late diastole – blood flows into ventricles
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– Ventricular systole – blood pressure builds before
ventricle contracts, pushing out blood
– Early diastole – atria finish re-filling, ventricular pressure
is low
Heart sounds – __________ (closing AV valves) _______
(semilunar valves close)
Heart murmur – abnormal or unusual heart sounds
– From blood hitting thin walls
– Valves not closing tightly
– Narrowed valves
The Heart: Cardiac Output
– ___________________ Amount of blood pumped by each side of the heart in
one minute
– CO = (heart rate [HR]) x (stroke volume [SV])
• Stroke volume
– Volume of blood pumped by each ventricle in one contraction
The Heart: Regulation of Heart Rate
• Stroke volume usually remains relatively constant
– Starling’s law of the heart – the more that the cardiac muscle is stretched, the
stronger the contraction
• Changing heart rate is the most common way to change cardiac output
• Increased heart rate
– Sympathetic nervous system
• Crisis
• Low blood pressure
– Hormones
• Epinephrine
• Thyroxine
– Exercise
– Decreased blood volume
• Decreased heart rate
– Parasympathetic nervous system
– High blood pressure or blood volume
– Dereased venous return
Homeostatic Imbalance
• Congestive heart failure – pumping efficiency of heart is diminished
– Often from clogging of coronary arteries (atherosclerosis), persistent high blood
pressure, and MI
• _______________________________– left side of heart fails so blood not pumped out
to body, but blood continues to move into lungs causing fluid to leak into lungs
– Can lead to suffocation
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Blood Vessels: The Vascular System
• Taking blood to the tissues and back
– ___________________ (away from heart)
– Arterioles
– Capillaries
– Venules
– ___________________ (toward heart)
Differences Between Blood Vessel Types
• Walls of arteries are the thickest
• Lumens of veins are larger
• Skeletal muscle “milks” blood in veins toward the heart
• Walls of capillaries are only one cell layer thick to allow for exchanges between blood
and tissue
Movement of Blood Through Vessels
• Most arterial blood is pumped by the heart
• Veins use the milking action of muscles to help move blood
• Capillary beds consist of two types of vessels
– Vascular shunt – directly connects an arteriole to a venule
• True capillaries – exchange vessels
• Oxygen and nutrients cross to cells
• Carbon dioxide and metabolic waste products cross into blood
Homeostatic Imbalance
• Varicose veins – pooling of blood in feet and legs and inefficient venous return
resulting from inactivity or pressure on the veins; veins become twisted and dilated
• Thrombophlebitis – inflammation of vein that results when clot forms in a vessel with
poor circulation; if the clot moves to the lungs it causes a pulmonary embolism
Pulse
• ___________________ – pressure wave of blood
• Monitored at “pressure points” where pulse is easily palpated
Blood Pressure
• Measurements by health professionals are made on the pressure in large arteries
– ___________________ – pressure at the peak of ventricular contraction
– ___________________ – pressure when ventricles relax
• Pressure in blood vessels decreases as the distance away from the heart increases
Blood Pressure: Effects of Factors
• Neural factors
– Autonomic nervous system adjustments (sympathetic division)
• Renal factors
– Regulation by altering blood volume
– ___________________ – hormonal control
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Temperature
– Heat has a vasodilation effect
– Cold has a vasoconstricting effect
Chemicals
– Various substances can cause increases
or decreases
Diet
Variations in Blood Pressure
• Human normal range is variable
– Normal
• 140–110 mm Hg systolic
• 80–75 mm Hg diastolic
– Hypotension
• Low systolic (below 110 mm HG)
• Often associated with illness
– ______________________________
• High systolic (above 140 mm HG)
• Can be dangerous if it is chronic; weakens myocardium and causes
atherosclerosis
Capillary Exchange
• Substances exchanged due to concentration gradients
– Oxygen and nutrients leave the blood
– Carbon dioxide and other wastes leave the cells
Capillary Exchange: Mechanisms
• Direct diffusion across plasma membranes
• Endocytosis or exocytosis
• Some capillaries have gaps (intercellular clefts)
– Plasma membrane not joined by tight junctions
• Fenestrations of some capillaries
– Fenestrations = pores
Developmental Aspects of the Cardiovascular System
• A simple “tube heart” develops in the embryo and pumps by the fourth week
• The heart becomes a four-chambered organ by the end of seven weeks
• Few structural changes occur after the seventh week
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