AP2

Force the blood exerts against the inner walls of all blood vesse

• Rises when the ventricles contract
• Falls when the ventricles relax

Maximum pressure during ventricular contraction

Minimum pressure when the ventricles relax

• Blood enters the arterial system during ventricular systole, the elastic walls of the arteries stretch
• Pressure begins to dec. almost immediately at end of the ventricular contraction & the artery walls recoil
• Strong radial pulse indicates high b.p. & weak radial pulse indicates low b.p.

• Heart rate = Pulse rate
• Stroke vol =Vol of blood discharged frm the ventricle w/ each contraction, abt 70 ml for an avg. male @ rest
• Cardiac output = Vol of blood discharged frm the ventricle in 1 min = Stroke vol X H.R.

• Blood vol = Vol of formed elements + Vol of plasma
• ~5 liters for avg adult
• Directly proportional to vol of blood w/in cardiovascular sys
• Changes in vol initially change b.p., then body attempts to return body to normal b.p.

• Cause=friction btw blood & walls of blood vessels
• Slows blood flow
• Must overcome by b.p. so blood continues to flow
• Contraction of walls of arteries & arterioles raises b.p., but helps to move blood against peripheral resistance
• Elastic recoil of artery walls maintains some b.p. during diastole & converts intermittent flow of blood in arteries to smoother flow in capillaries

• Ease of flow of blood components past each other
• Blood cells and some blood proteins increase viscosity

• B.P. is determined by cardiac output (CO) & peripheral resistance (PR)
• BP = CO x PR
• Maintenance of b.p. requires regulation of CO & PR
• C.O. limited by venous return to ventricles

• Can be influenced by contractility, the force produced during a contraction when a given vol of blood is in the ventricle immediately prior to contraction
• Influenced by autonomic nervous sys & hormones
• EX: epinephrine, norepnephrine, & thyroid hormones
• Influenced by arterial blood pressure detected by baroreceptors in the aortic arch & the carotid sinuses

• B.P. decreases as the blood moves through the arterial sys & into the capillary network, so little pressure remains at the venular ends of the capillaries
• Only partly a directresult of heart action
• Dependent on:
• Skeletal Muscle Contraction
• Breathing
• Venoconstriction

• Pressure in the right atrium
• All veins, except those returning to the heart from the lungs, drain into the right atrium
• Affects pressure within the peripheral veins
• Weak heart beat increases central venous pressure
• Increase in central venous pressure causes blood to back up into the peripheral veins

• The pulmonary circuit
• The systemic circuit

• Between heart & lungs only
• Pulmonary trunk divides into lt & rt pulmonary arteries, which divide into lobar branches, which enter the lungs
• After further divisions, arterioles continue into
• capillary networks associated w/ the walls of the alveoli, aka, air sacs
• Gas exchange occurs btw air in alveoli & blood in the capillary networks
• Slightly different hydrostatic osmotic forces push fluid
• out of the capillary and into alveolar tissues
• Epithelial lining of alveoli prevents transfer of ions & H20 frm the interstitial fluids into the alveoli
• Excess interstitial fluids drawn back into capillary by
• osmosis or into lymphatic vessels

• Composed of vessels that lead frm the heart to all body parts (except the lungs) & back to the heart
• Includes the aorta & its branches
• Includes the sys of veins that return blood to the rt atrium

• Return blood to the heart after gas, nutrient, & waste exchange in the tissues of the body
• Vessels of the venous sys originate w/ the merging of capillaries into venules, venules into small veins, & small veins into larger ones
• Unlike arterial pathways, those of the venous sys are difficult to follow due to irregular networks & unnamed tributaries
• Larger vessels usually parallel arteries

• Cholesterol deposit in the blood vessels
• Heart enlargement caused by cardiovascular disease
• Death of cardiac muscle cells
• Increase in fibrous connective tissue of the heart
• Increase in adipose tissue of the heart
• Valves may thicken or calcify
• S-A & A-V nodes and A- V bundle become more elastic & may alter the ECG
• Inc. in b.p. due to dec. diameter of blood vessels & dec. elasticity of arteries
• Decrease in resting heart rate
• Number of capillaries decreases
• Veins change less with age than do arteries

• Is a vast collection of cells & biochemicals that travel in lymphatic vessels & the organs & glands that produce them
• Is a network of vessels that assist in circulating fluids
• Is closely associated with the cardiovascular system
• Transports excess fluid away from the interstitial spaces
• Transports fluid to the bloodstream
• Transports fats to the bloodstream
• Helps defend the body against diseases

• Begin as lymphatic capillaries
• Merge to form larger lymphatic vessels
• Largest lymphatic vessels unit with veins in the thorax

• Microscopic, closed-ended tubes
• Located in interstitial spaces
• Networks parallel networks of blood capillaries
• Walls similar to those of blood capillaries
• The fluid in the vessels is called lymph
• Special lymphatic capillaries in the lining of the sm. intestine absorb digest fats & transport them to venous circulation

• Walls are similar to but thinner than those of veins
• Lymphatic vessels are composed of three layers
• Have semilunar valves to help prevent backflow
• Larger vessels lead to lymph nodes and then to larger lymphatic trunks

• An endothelial lining (inner)
• Smooth muscle & elastic fibers (middle)
• Connective tissue (outer)

• Trunks drain lymph from the lymphatic vessels
• Named for the regions they serve.such as lumbar, intestinal, intercostal, bronchomediastinal, subclavian, & jugular
• Rt lymphatic duct starts at the union of the right jugular, right subclavian, & right bronchomediastinal trunks & dumps into the subclavian vein near the junction of the rt jugular vein
• Lt lymphatic duct begins in the abdomen, passes upward through the diaphragm beside the aorta, ascends anterior to the vertebral column through the mediastinum, & empties into the lt subclavian vein near the junction of the lt jugular vein

• Lymph is essentially tissue fluid that has entered a lymphatic capillary
• Lymph formation depends on tissue fluid formation

• Capillary b.p. filters H20 & sm molecules frm plasma
• Fluid contains:
• Much the same composition as plasma
• Includes nutrients, gases, and hormones
• Contains water and dissolved substances
• Smaller proteins which create plasma colloid osmotic pressure
• Lacks plasma proteins due to their large size

• Filtration from the plasma normally exceeds reabsorption, leading to the net formation of tissue fluid
• This increases the tissue fluid hydrostatic pressure within interstitial spaces forcing fluid into lymphatic capillaries forming lymph
• This process prevents accumulation of excess tissue fluid (edema)

• Absorption of dietary fatsDelivery of fats to the bloodstream
• Collection of small proteins filtered out of the blood capillaries
• Delivery of these small proteins to the blood stream
• Collection of excess interstitial fluids
• Delivery of excess fluids to the bloodstream
• Delivery of foreign particles, such as bacteria & viruses, to the lymph nodes

7,000 liters

2.5 billion times

O2 depleated blood goes to lungs to release CO2 and gain O2

• O2 rich blood goes to all body cells
• Wastes collected from body cells

• 14 cm long
• 9 cm wide

• Fibrous pericardium
• Visceral pericardium
• Parietal pericardium

• Outer sac
• Fibrous and tough

Inner of two layers of serous membrane

• Inner lining of the fibrous pericardium
• Contiguous with visceral pericardium

• between visceral and parietal pericardia
• Contains serous fluid, reduces friction b/t membrane layers during movement

• Epicardium (outer layer)
• Myocardium
• Endocardium

• Aka, visceral pericardium
• Protects the heart by reducing friction
• Serous membrane of connective tissue covered by epithelium
• Has nerve fibers & blood and lymph capillaries
• Has fat in deeper layers, especially near coronary
• arteries & cardiac veins

• Thick
• Responsible for pumping action of heart
• Mostly cardiac muscle tissue
• Muscle fibers are arranged in planes separated by connective tissue &richly supplied with nerve fibers & blood & lymph capillaries

• •Epithelium & underlying connective tissue
• Lines all heart chambers, covers valves, & is continuous w/ inner linings of blood vessels
• Contains blood vessels
• Contains specialized cardiac muscle fibers called Purkinje fibers

• Separate parts of the heart
• Interatrial septum separates right and left atrium
• Interventricular septum separates right and left ventricle

• Grooves on surface of heart marking divisions b/t chambers of heart
• Contains major arteries & veins that supply heart tissue
• Atrioventricular sulcus encircles heart between atria & ventricles
• Interventricular sulci separate right and left ventricle
• Anterior & posterior

• Strong, fibrous strings attached to cusps on ventricular side
• Originate frm papillary muscles, which contract when ventricle contracts to prevent cusps frm swinging backward into atrium during contraction

Provide alternate routes of blood flow in case a capillary becomes blocked

• Heart actions are regulated so that atria contract (atrial
• systole) while ventricles relax (ventricular diastole); followed by ventricles contract (ventricular systole) while atria relax (atrial diastole)

30%

• Heat sound:
• The “lubb”
• The first heart sound
• Occurs during ventricular systole
• The A-V valves are closing
• The “dupp”
• The second heart sound
• Occurs during ventricular diastole
• The pulmonary and aortic semilunar valves are closing
• Murmur: abnormal heart sound frm the cusps not completely closing

Cardiac muscle fibers form a functional syncytium, a mass of merging cells that act as a unit

• SA Node -
• Atrial Synctium -
• Junctional Fibers -
• AV Node -
• AV bundle -
• Bundle Branches
• Purkinje fibers
• Ventricular synctium

Sinoatrial node (SA Node)

Recording of electrical changes that occur in the myocardium during the cardiac cycle

Slow atrial depolarization triggered by a cardiac impulse frm the S-A node

• Rapid depolarization
• Walls are thick so greater change in electrical potential so stronger deflection/signal

Slow ventricular repolarization

• SA node controls heart rate
• Sympathetic and parasympathetic fibers that control the heart rate
• Regulatory reflex centers that influence heart rate
• Additional factors that may influence heart rate include:
• Physical exercise
• Body temperature
• Concentration of various ions including:
• Potassium
• Calcium

• Arteries - carry blood away from the ventricles of the
• heart
• Arterioles - receive blood from the arteries and carry blood to the capillaries
• Capillaries - sites of exchange of substances between the blood and the body cells
• Venules -receive blood from the capillaries
• Veins - carry blood toward the atria of the heart

• Thick strong wall (three layers or tunics)
• Endothelial- tunica interna
• Middle layer- tunica media
• Thickest layer of arterial wall
• Outer layer- tunica externa or adventitia
• Thin

• Thick, strong wall with three layers
• -Endothelial lining
• -Middle layer of smooth muscle & elastic tissue
• -Outer layer of connective tissue

Carries blood under relatively high pressure from heart to arterioles

• Thinner wall than an artery but w/ 3 layers
• Smaller arterioles have:
• -endothelial linning
• -some smooth muscle tissue
• -small amt of connective tissue

• Connects an artery to a capillary
• helps control the blood flow into a capillary by vasoconstricting or vasodilating

Single layer of squamous epithelium

• Provides a membrane through which nutrients, gases, & wastes are exchanged b/t the blood & tissue
• Connects an arteriole to a venule

• Thinner wall than an arteriole
• less smooth muscle & elastic tissue

Connects a capillary to a vein

• Thinner wall than an artey but with smaller layers
• middle layer is poorly developed
• some have flaplike valves

• Carries blood underrelatively low pressure from a venule to the heart
• Valves prevent a backflow of blood
• Serves as blood reservoir

• Smallest diameter blood vessels
• Semi-permeable to allow exchange of substances b/t blood & interstitial fluid

• Methods of exchange:
• Diffusion
• Most important
• O2, nutrients, CO2, wastes
• Lipid solubility determines if diffusion is directly through the cell wall or through pores
• Plasma proteins trapped in capillary b/c they are not lipid soluble & too large to pass through pores
• Filtration
• Hydrostatic pressure frm ventricular contractions forces molecules through membranes
• Force reduced w/ greater distance frm heart due to friction
• Osmosis
• Due to impermeable solute on one side of membrane
• Plasma proteins

• Superior vena cava
• Inferior vena cava
• Pulmonary trunk
• Left and right pulmonary arteries
• Left and right pulmonary veins
• Aorta/Aortic arch
• Left and right coronary arteries

• Brachiocephalic
• Common carotid arteries
• Subclavian arteries
• Celiac arteries
• Phrenic arteries
• Mesenteric arteries

• Radial arteries
• Femoral arteries

• Brachiocephalic veins
• Internal jugular veins
• External jugular veins
• Subclavian veins
• Hepatic portal vein
• Mesenteric veins

• Radial arteries
• Femoral arteries

• Vast collection of cells and biochemicals that travel in lymphatic vessels and the organs and glands that produce them
• Network of vessels that assist in circulating fluids
• Closely associated with the cardiovascular system
• Transports excess fluid away from the interstitial spaces
• Transports fluid to the bloodstream
• Transports fats to the bloodstream
• Helps defend the body against diseases

• Begin Lymphatic capillaries
• Merge to form larger lymphatic vessels
• Largest lymphatic vessels unite w/ veins in the thorax

Fluid in the lymph vessels

• Hydrostatic pressure of tissue fluid drives the lymph into the lymphatic capillaries
• Epithelial cells of walls of lymphatic capillaries overlap but are not attached to each other creating flap-like valves
• Valves are pushed open when fluid pressure is greater in the interstitial spaces than in the lymph vessel & close when the pressure is greater inside the vessel
• Epithelial cells of capillary wall are attached to surrounding connective tissue cell by thin protein filaments

• Blood vessels and nerves enter through the concave region called the hilum
• Afferent lymph vessels enter nodes separately and at various locations on the node’s convex surface
• Efferent vessels leave the node from the hilum
• A capsule of connective tissue with numerous fibers encloses the node and subdivides it into compartments called lymph nodules
• Germinal centers within nodules contain actively
• dividing lymphocytes and monocytes
• Lymph nodules occur singly and in groups associated w/ mucous membranes of the respiratory & digestive tracts
• Lymph sinuses are spaces w/in the nodes that provide a complex network of chambers & channels through
• which the lymph circulates

• Lymph nodes are found in groups or chains along the paths of the larger lymphatic vessels throughout the body, including the:
• Cervical region
• Axillary region
• Supratrochlear region
• Inguinal region
• Pelvic cavity
• Abdominal cavity
• Thoracic cavity

• Lymph nodes have two primary functions:
• Filter potentially harmful particles from the lymph before returning it to the blood stream
• Provide immune surveillance using macrophages & lymphocytes
• Attack viruses, bacteria, & other parasites that reach the lymph nodes
• Macrophages phagocytize foreign substances, damaged cells, & cellular debris
• Along with the red bone marrow, the lymph nodes are centers for lymphocyte production

Thymus and Spleen

• Larger in infancy and during puberty
• Small in an adult
• Replaced by fat and connective tissue in the elderly
• Subdivided into lobules by connective tissue extending inward frm the surface
• Site of T lymphocyte (or T cell) production
• Secretes protein hormones called thymosins that induce maturation of T cells after they migrate to other lymphatic tissues

• largest lymphatic organ
• Located in the upper left abdominal quadrant
• Has sinuses filled with blood (the major difference from large lymph nodes)
• Contains two tissue types:
• White pulp
• -In tiny islands throughout spleen
• -Contains lymphocytes
• Red pulp
• -Rest of lobules
• -Contains red blood cells, lymphocytes & macrophages

• The skin & mucous membranes create mechanical barriers
• Considered the first line of defense (all other non-specific defenses are part of the second line of defense)

• Chemical barriers
• Natural killer cells
• Inflammation
• Phagocytosis
• Fever

• Enzymes in body fluids provide a chemical barrier to pathogens, and they may include:
• Interferons are horomone-like peptides and stimulate phagocytosis
• Defensins are peptides produced by neutrophils & other granulocytes. They cripple microbes.
• Collectins are proteins w/ broad protection against bacteria, yeast & some viruses
• Complement is a group of proteins in plasma & other body fluids that stimulate inflammation, attract phagocytes & enhance phagocytosis

• NK cells are a small population of lymphocytes defending against viruses & cancer by secreting cytolytic substances called perforins that destroy the infected cell
• NK may also enhance inflammation

Inflammation produces local redness, swelling, heat and pain

• Removes foreign particles from the lymph
• In the blood vessels and in the tissues of the spleen, liver or bone marrow
• The most active phagocytic cells are neutrophils and monocytes
• Chemicals attract these phagocytic cells to the injury and this is called chemotaxis

Begins when a viral or bacterial infection stimulates lymphocytes to proliferate, producing cells that secrete a substance called interleukin-1 (IL-1)

• Third line of defense and known as immunity
• It is resistance to particular pathogens or to their toxins or metabolic by-products
• It is based on the ability to distinguish molecules that are part of the body (“self” from “non-self”)
• Antigens are molecules that can elicit an immune response

• Antigens may be:
• Proteins
• Polysaccharides
• Glycoproteins
• Glycolipids
• The most effective antigens are large and complex
• Haptens are small molecules that are not antigenic by themselves, but when they combine with a large molecule can stimulate an immune response

• A lymphocyte must be activated before it can respond to an antigen
• T cell activation requires antigen-presenting cell (accessory cell) and may include macrophages, B cells and several other types of cells
• Requires major histocompatibility complex (MHC) or human leukocyte antigens (HLA) to recognize “non-self”
• T cells can synthesize and secrete polypeptides called
• cytokines
• Types of specialized T cells include:
• -Helper T cells
• -Cytotoxic T cells
• -Memory T cells

• B cells can be activated when an antigen fits the shape of its receptor
• Most of the time B cell activation requires T cells
• T cells release cytokines that stimulate B cells
• Some B cells may become memory B cells while others differentiate into plasma cells and produce and secrete large globular proteins called antibodies or immunoglobulins

• Type I
• -Immediate-reaction allergy
• -Occurs minutes after contact with allergen
• -Symptoms include hives, hay fever, asthma, eczema, gastric disturbances, and anaphylactic shock
• Type II
• -Antibody-dependent cytotoxic reaction
• -Takes 1-3 hours to develop
• -Transfusion reaction
• Type III
• -Immune-complex reaction
• -Takes 1-3 hours to develop
• -Antibody complexes cannot be cleared from the body
• -Damage of body tissues
• Type IV
• -Delayed-reaction allergy
• -Results from repeated exposure to allergen
• -Eruptions and inflammation of the skin
• -Takes about 48 hours to occur

• Successfully transplanted tissues and organs:
• -Cornea
• -Kidney
• -Liver
• -Pancreas
• -Heart
• -Bone marrow
• -Skin
• When the donor’s tissues are recognized as foreign there is a tissue rejection reaction
• -Resembles the cellular immune response against antigens
• -Important to match MHC antigens
• -Immunosuppressive drugs used to prevent rejection

• Isograft
• Donor: Identical twin
• EX: Bone marrow transplant from a healthy twin to a twin who has leukemia
• Autograft
• Donor: Self
• Ex: Skin graft from one part of the body to replace burned skin
• Allograft
• Donor: Same species
• Ex: Kidney transplant from a relative or close matched donor
• Xenograft
• Donor: Different species
• Ex: Heart valves from a pig