Cardiovascular System

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Cardiovascular System
2015-02-02 20:47:10
Anatomy Physiology

Exam of 2/4/2015
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  1. Components of the cardiovascular system
    • heart
    • blood
    • blood vessels
    • blood forming & destroying cells
  2. What system is connected to the circulatory system?
    lymphatic system- structurally and functionally
  3. Functions of circulatory system
    • transportation
    • regulation of body functions and homeostasis
    • protection
  4. Transportation
    • the distribution of substances to and from cells in the blood
    • nutrients & O2 transported to cells
    • CO2 + wastes removed from cells to be excreted (through lungs or urinary system)
    • red blood cells- important for CO2 and O2 transport
    • hormones also transported through this system
  5. Regulation of Body Functions + homeostasis
    • Body Temperature: blood carries heat in addition to specific chemicals
    • Acid-Base balance: maintained through buffers in the blood
    • Homeostasis of fluid volume in body and blood pressure (fluid volume influenced by water and various solutes in it- protein, salts etc)
  6. Protection
    • against physical injury by preventing blood loss (platelets are critical for blood clotting)
    • against infectious diseases (white blood cells)
  7. Blood
    • the liquid that circulates through the heart and blood vessels
    • a fluid connective tissue, composed of formed elements (cells)
  8. composition of blood
    • cells compose 45% of total blood
    • "whole blood" -including cells, all of the blood
    • plasma- 55%
    • WBCs and platelets make up less than 1% of whole blood
  9. plasma
    • the intercellular fluid of the blood
    • no cells, least dense
  10. 3 types of blood cells
    • Erythrocytes: RBCs- most numerous
    • Leukocytes- WBCs
    • Platelets- cell fragments
  11. Characteristics of blood
    • Red in color due to RBCs carrying hemoglobin with red pigment
    • 5x more thick than water (due to RBCs and proteins)
    • pH kept between 7.35 and 7.45
    • makes up 8% of your body weight
  12. How does O2 in blood affect its color
    • more o2- bright red
    • less o2- deeper red
  13. How much blood do women and men have approximately
    • women: 4-5 liters
    • men: 5-6 liters
  14. Composition of blood plasma
    • 90% water
    • 10% solutes
  15. solutes in plasma
    • plasma proteins- most abundant type
    • nutrients
    • nitrogen containing wastes
    • o2
    • co2
    • electrolytes
    • hormones
  16. Where are most plasma proteins made?
    • the liver
    • hormones and gamma globulins (antibodies) are an exception
  17. Plasma protein functions
    • viscosity (thickness) and maintaining osmotic pressure
    • important in blood pressure
  18. types of plasmid proteins
    • albumin
    • prothrombin
    • globulins
    • fibrinogen
  19. Albumin
    • most abundant plasma protein
    • key for function of osmotic pressure
    • carrier for fat soluble substances (ex- estrogen) (makes them water soluble)
    • important as buffer
  20. prothrombin
    • a type of albumin
    • blood clotting factor
  21. globulins
    • alpha and beta globulins: transport proteins transporting lipids and metals
    • gamma globulins: antibodies, made in plasma cells, a type of WBC
  22. fibrinogen
    a blood clotting factor
  23. Red Blood Cells
    • most numerous
    • very small and anucleate when matured
    • a biconcave disc due to extrusion of nucleus (cell caves in to get rid of nucleus when adult)
    • streamlined for transport of gasses
    • contain hemaglobin
    • red blood cells get smaller until they eject the nucleus
  24. Hemaglobin- parts
    • glob in: protein part made of 4 polypeptide chains; this part binds to CO2
    • heme: red pigmented compound; one attached to each chain; contains iron that binds to oxygen
    • 4 oxygen per hemaglobin
  25. Hematopoesis
    the synthesis of blood cells
  26. Erythropoesis
    • the synthesis of RBCs
    • happens in the red  (active myeloid tissue) bone marrow
  27. Hemocytoblast
    • the hemopoetic stem cell
    • all blood cells come from these
  28. reticulocyte
    form of RBC released in the blood which then releases the nucleus to become the mature RBC
  29. How long does the process of erythropoesis take
    about 15 days
  30. how long do RBCs live
    • about 120 days
    • they keep replenishing
  31. what does the process of erythropoeisis require
    • iron to make hemoglobin 
    • 2 B vitamins (folic acid + vitamin B12) to stimulate the process
    • Erythropoietin hormone (made in kidneys)
  32. Erythropoietin hormone
    • triggered by things such as low RBC count, low amount of hemoglobin, low oxygen availability for the body (hypoxia)
    • used therapeutically to increase RBC production for example in cancer
    • abused by athletes
  33. WBCs general function
    defense against microbes, toxins and foreign substances/cells
  34. 5 types of WBC all have some ability for
    phagocytosis: 2 engulf and destroy; some can migrate into tissues and destroy
  35. how can you know the number of each type of WBC
    • they can be determined by a differential WBC count
    • a higher level of one type could indicate a certain disorder
  36. granuloleukocytes
    • granules are visible in the cytoplasm of the WBC when you stain the blood smear
    • 3 of the 5 types of WBCs are these
  37. 5 types of WBCs
    • neutrophils
    • eosinophils
    • basophils
    • ---> these first 3 are granuleukocytes 
    • lymphocytes
    • monocytes
  38. neutrophils
    • stain best with neutral dyes
    • have a multi-lobe nucleus and granules in cytoplasm
    • usually most common
    • specialize in phagocytosis in bacteria
    • especially important in short term infection
  39. eosinophils
    • stain best with acidic dyes
    • granules appear very red
    • 2 lobe nucleus
    • important in allergies- inactivate foreign chemicals are predominant in an allergic reaction
    • also can kill parasitic worms
  40. basophils
    • stain best with basic dye
    • granules are purple-black
    • important in inflammations- they release histamine (a vasodilator- widens bcd to increase blood flow to affected area)
    • contain heparin (coagulant that prevents abnormal blood clots)
  41. Lymphocytes
    • smaller, important in immune response
    • can directly attack the foreign cells/chemicals or they can attack by making antibodies
    • ex: plasma cells are a type of lymphocytes
  42. monocytes
    • use phagocytosis to protect
    • in tissues they develop into macrophages (large phagocytic cells)
    • important in long term chronic infections
  43. Platelets
    • made in bone marrow by the fragmentation of larger cells called megakaryocytic
    • life span- about 10 days
    • synthesis of platelets is stimulated by thrombopoeitin
  44. platelet function
    to set up the blood clotting mechanism (coagulation)
  45. hemostasis
    • stoppage of bleeding
    • coagulation is part of this process
  46. what happens if you are cut
    • 1. vasoconstriction or vascular spasm occurs to prevent blood loss- tightening the vessel
    • 2. platelet plug forms 
    • 3. blood clotting
  47. What does blood clotting require
    • platelets 
    • 12 clotting factors called procoagulants
    • blood clotting is a cascade effect- keeps going until vessel is plugged with a clot
    • inactive compounds that are already in the blood (including plasmid proteins and calcium) become active clotting factors
  48. Blood transfusions
    compare the donors antigens to the recipients antibodies
  49. Type A blood
    • Antigen on RBC: A
    • Contains antibodies: anti-B
    • Can donate to: A or AB
    • Can receive from: A or O
  50. Type B blood
    • Antigen on RBC: B
    • Contains antibodies: anti-A
    • Can donate to: B or AB
    • Can receive from: B or O
  51. Type AB blood
    • Antigen on RBC: A and B
    • Contains antibodies: neither-universal recipient 
    • Can donate to: AB only
    • Can receive from: Any
  52. Type O blood
    • Antigen on RBC: neither (universal donor)
    • Contains antibodies: anti-B and anti A
    • Can donate to: all
    • Can receive from: O only
  53. What is the Rh factor
    • Rh+ blood has the Rh antigen on RBCs, Rh- does not
    • Good transfusions: Rh- to Rh+, Rh- to Rh-, Rh+ to Rh+
  54. Are there anti Rh antibodies
    • no, unless an Rh- person gets Rh+ blood, then they are made
    • this can happen in a bad transfusion or pregnancy when Rh- mom has Rh+ fetus
  55. What happens in the pregnancy of an Rh- mom with Rh+ fetus
    • mom can make antibodies which travel to fetus and destroy fetal RBCs
    • treated by injecting Rh- mother after birth so not make antibodies
  56. Memorize blood clotting mechanism- coagulation sheet
  57. Pericardium
    • double layered sac
    • covering of the heart
  58. pericardium layers
    • fibrous pericardium
    • serous pericardium
  59. fibrous pericardium
    • dense connective tissue
    • losse over heart
    • lubricates, protects, anchors and prevents overfilling of heart
  60. serous pericardium
    • contains 2 layers
    • parietal layer
    • visceral layer
  61. parietal layer
    lines fibrous pericardium (pericardial cavity with pericardial fluid between layers, prevents friction)
  62. visceral layer
    • on the heart itself 
    • also called epicardium- part of heart wall
  63. heart wall layers
    • Epicardium: outermost, membrane on surface
    • Myocardium: middle layer, cardiac muscle beneath pericardium and epicardium
    • Endocardium: inner layer, membrane lining chambers, covers valves and continuous with endothelial lining of blood vessels
  64. Heart chambers
    • atria: 2 upper, small chambers, right and left
    • ventricles: 2 lower chambers, right and left
  65. Heart valves
    • ensure one way flow of blood
    • 2 types: atrioventricular valves (bi and tricuspid valves) and semilunar valves
  66. Arteries- carry direction
    • carry blood from heart to organs
    • oxygenated blood, except for pulmonary arteries
  67. Veins- carry direction
    • carry blood from organs to heart
    • deoxygenated blood, except pulmonary veins
  68. Circulation of blood- 2 types
    • systemic circulation: to and from body tissues except lungs
    • pulmonary circulation: flow of blood to and from lungs
  69. Circulation of left and right sides of heart
    • Right: pulmonary circuit pump (to lungs)
    • Left: systemic circuit pump (to tissues other than lungs)
  70. pulmonary circuit pump
    • collect deoxygenated blood (low o2 high co2) and sends it to lungs
    • from veins to superior and inferior vena cava to RA to RV to lungs via pulmonary trunk and arteries to lungs for gas exchange (rid co2, get o2)
  71. Systemic circuit pump
    collect oxygenated blood (high o2 low co2) from lungs via pulmonary veins to LA to LV to aorta to arteries to tissues for gas exchange (tissues pick up o2 and release co2 into blood)
  72. Attached to right atrium
    • superior vena cava 
    • inferior vena cava
  73. attached to right ventricle
    pulmonary trunk branching into 2 pulmonary arteries
  74. attached to left atrium
    2 pulmonary veins (empty into it)
  75. Attached to left ventricle
    aorta (largest)- all systemic arteries branch off of this
  76. How does the heart pump blood
    • nature of cardiac muscle 
    • regulation of heart beat
    • components of the conduction system
  77. nature of cardiac muscle
    • myocardium is critical- involuntary striated cells that are short (unlike skeletal muscle), branched and interconnectedcells electrically coupled to contract in coordinated way
    • branching important for simultaneous coordinated contraction
  78. Regulation of heart beat
    • the heart generates its own beat in humans, but we have nervous impulses that can slow and speed it, but naturally it is automatic
    • you are born with an intrinsic rhythm 
    • intrinsic cardiac conduction (does not rely on NS but is influenced by autonomic)
    • auto rhythmic cells generate impulses and send through heart (not Ns, automatic impulses in a pattern that spreads through the muscle)
  79. components of conduction system
    • sinoatrial node
    • atrioventricular node
    • atrioventricular bundle (bundle of his)
    • R+L bundle branches
    • purkinje fibers
    • impulses spread to the atria first which contract simultaneously, then ventricles which contract simultaneously
  80. sinoatrial node
    SA node, natural pacemaker in RA  near superior vena cava- group of cells that generate impulses
  81. atrioventricular node
    • AV node in lower RA in intertribal septum
    • impulse goes from here to atrioventricular bundle
  82. atrioventricular bundle
    • bundle of his 
    • in interventricular septum
    • impulse goes from here to R+L bundle branches
  83. R+L bundle branches
    impulse travels from here to Purkinje fibers
  84. purkinje fibers
    extending into ventricular muscle
  85. Regulation of heart rate
    • autonomic nervous system
    • cardiac centers in medulla oblongata
    • hormones
  86. autonomic nervous system- heart rate regulation
    • sympathetic: increases rate and force of heartbeat via norepinepherine from cardiac sympathetic nerve
    • parasympathetic: decreases rate via acetylcholine from vagas nerve
  87. cardiac centers in medulla oblongata- heart rate regulation
    • cardioacceleratory center (sympathetic) to SA (sets pace), AV nodes, heart muscle, coronary artery
    • cardioinhibitory center (parasympathetic) to SA and AV nodes only
  88. Hormones- heart rate regulation
    • epinephrine increases rate and force of contraction
    • thyroid hormone slower, more stimulation of heart, enhances eli and NE
  89. ECG
    impulse conduction through heart, measure through skin
  90. Cardiac cycle
    • events of complete heartbeat (about .8 sec, 75 beats per minute)
    • 1. 2 atria relaxed, fill with blood (AV valves closed) then contract simultaneously and AV valves open and pressure pushes blood to ventricles (relaxed while they fill) and semilunar valves closed so ventricles can fill efficiently
    • 2. 2 ventricles contract, semilunar valves open to push blood out the aorta and pulmonary trunk, AV valves close to avoid blood backing up and atria fill for next contraction
  91. systole
    • contraction of chamber (systolic)
    • usually refers to ventricles
  92. diastole
    • relaxation of chamber (diastolic)
    • blood pressure numbers relate to systole and diastole
  93. 2 distinct heart sounds heard through stethoscope
    • 1. systolic sound when ventricles contract, due to closing of AV valves (lub dub)
    • 2. diastolic sound when ventricles relax, due to closing of semilunar valves (quieter sound)
  94. Cardiac output
    • amount of blood pumped by ventricle in one minute (liters)
    • equal to heart rate times stroke volume
  95. heart rate units
    beats per minute
  96. stroke volume
    volume of blood pumped by ventricle in one contraction
  97. Disorders of circulatory system
    • heart murmur
    • heart block
    • congestive heart failure
    • myocardial infarction
    • tachycardia
    • brachycardia
    • ectopic heart beat
    • heart palpitations
  98. heart murmur
    • abnormal heart sounds (normal should be crisp)
    • may be due to incomplete valve closings
    • usually mild
  99. heart block
    • not the blockage of blood vessels or blood flow
    • impaired impulses from atria to ventricles
    • damage to AV node (which is in the intertribal septum of right atrium)
    • impulses are blocked- slow heart rate
    • need artificial pacemaker
  100. congestive heart failure
    • Cardiac output so low that circulation is inadequate
    • ex- due to weak myocardium- muscle in heart tissue
  101. myocardial infarction
    • heart attack
    • dead tissue areas of myocardium due to blocked blood coronary blood supply
  102. where is the pacemaker
    right atrium
  103. why is the myocardium on the left thicker than the right?
    bc left pumps blood everywhere while right is just lungs
  104. Tachycardia
    a fast heart rate so that at resting, a person may have more than 100 bpm
  105. brachycardia
    a slow heart rate so that at resting a person may have less than 60bpm
  106. ectopic heart beat
    • a change in the usual heartbeat 
    • there can be an extra or skipped beat
    • usually harmless with no clear cause
    • can happen from having a low potassium level, low blood supply, heart diseases, not common causes, but can make condition serious
  107. what is an extra heart beat also called in ectopic heart beat
    • extrasystole (contraction of chamber)
    • can be premature ventricular or atrial contraction
    • most go untreated fine, but may get worse if you smoke, drink a lot of alcohol, have high caffeine intake, use drug stimulants and other drugs
  108. Heart palpitations
    • sensation like the heart is pounding or racing
    • can be felt in chest, throat or neck
    • generally not serious- can be due to anxiety, stress, fear, caffeine, nicotine, exercise, fever
    • can be caused by abnormal rhythm (extrasystole, etc), heart valve problem, low blood o2, abnormal K+, overactive thyroid, heart disease
    • if the person has shortness of breath, chest pain, unusual sweating, dizziness you should see a doctor
  109. Blood vessels
    • arteries
    • veins
    • capillaries
  110. Arteries
    • carry blood from the heart to an organ
    • transport oxygenated blood except for pulmonary arteries which have deoxygenated blood and travel to the lungs
  111. Arteriole
    • small artery
    • branches off a larger artery
  112. 3 layers of arteries
    • 1. Tunica Intima
    • 2. Tunica Media
    • 3. Tunica Externa
  113. Tunica Intima
    the innermost layer- made of endothelial tissue (tissue that is one cell thick)
  114. Tunica Media
    • middle layer
    • smooth muscle
    • elastic fibers
    • much thicker than this layer in the veins
  115. Tunica Externa
    outermost fibrous layer
  116. veins
    • carry blood from the organs to the heart
    • carry deoxygenated blood except pulmonary veins which carry oxygen rich blood from the lungs to the heart
  117. venules
    small veins branching off larger veins
  118. 3 layers of veins
    • same but veins are thinner
    • they have much less tunica media (muscle)
  119. What do veins have that arteries dont
    • semilunar valves at intervals to ensure a one way flow of blood
    • veins are also thin and collapsable if cut, arteries are stronger
  120. Varicose veins
    • dilated and twisted veins due to inefficient leaky valves
    • if the valves are leaky, blood can flow back down if gravity acts
  121. capillaries
    • microscopic 
    • only made of endothelium (tunica intima)
    • they are one cell thick
  122. capillary function
    • exchange of substances between the blood and the tissues
    • --> o2+nutrients from blood to tissues
    • --> Co2 + waste from tissues to blood
    • the fact that capillaries are one cell thick allows for diffusion of these substances
  123. Systemic circulation- blood flow
    blood starts in heart, comes out the aorta, to the arteries to arterioles to capillaries, to venues, to veins to superior and inferior vena cava to heart
  124. What is blood circulation through vessels due to?
    differences in blood pressure in different parts of the body
  125. blood pressure
    • the force of blood against the blood vessel walls
    • measured with a sphygmomanometer
    • the units are in mmHg
    • upper number-systolic pressure-when the ventricles contract
    • lower number- diastolic pressure-ventricles relaxed
  126. where is the highest blood pressure
    aorta- where it joints the left ventricle of the heart has the highest bp, biggest place where blood is pumped, pumping action causes high bp
  127. area of lowest blood pressure
    where the vena cava join the right atrium- farthest place away from where the heart is pumping
  128. blood pressure gradient
    • blood flows down the blood pressure gradient from an area of higher bp to areas of lower bp
    • highest- aorta>arteries>arterioles>capillaries>venules>veins>vena cava- lowest
  129. why is bp in arteries greater than in veins
    b/c arteries are closer to the pumping of the heart and have more smooth muscle and elastic fibers in the tunica media
  130. Velocity (speed) of blood flow is related to the
    • blood vessel size
    • the wider the vessel, the faster the flow
    • in wide vessels nothing is preventing flow, no resistance, but narrower ones have more resistance causing slower flow
  131. where is the slowest flow of blood
    • capillaries because they are narrowest
    • this is good because it gives time for diffusion
  132. where is the fastest flow of blood
    • in the aorta and venacava because their wide
    • aorta>arteries>arterioles>capillaries<venules<veins<vena cava
  133. Regulation of venous blood pressure
    • you need to create pressure to work against gravity in the lower part of the body
    • 1. Respiratory "Pump"
    • 2. Muscular "Pump"
  134. Respiratory "pump"
    • different from circuit pump
    • you create a pressure gradient difference by breathing
    • inhale- chest expands, decreasing thoracic pressure and increasing abdominal pressure
    • pressure in abdomin>pressure in chest- pushes blood into chest
    • valves in veins prevent back flow of blood when you exhale
  135. Muscular "pump"
    • muscle contraction
    • contraction of skeletal muscles when you move puts pressure on nearby veins which push the blood along and valves prevent backup
    • inactivity/holding the same position can be a problem because the blood can collect (pool) and cause swelling (edema)
  136. Factors affecting arterial blood pressure
    • blood pressure is due to blood volume
    • -->the bigger the volume in an artery, the bigger the bp will be
  137. 2 factors regulating blood volume in arteries
    • cardiac output: the faster the heart rate and the stronger the heart contraction, the more blood volume and therefore higher blood pressure
    • perifferral resistance: resistance to blood flow; if something prevents the blood from flowing freely, the blood inside that vessel will build up
  138. peripheral resistance due to..
    the friction of the blood against the blood vessel walls
  139. friction of the blood against bv walls is due to..
    • blood viscosity: due to RBCs and plasma proteins as the main factors - thicker fluid= slower flow=more friction
    • small diameter: the more narrow the more resistance and the slower the flow; capillaries- most narrow
  140. arteriole sclerosis
    • abnormal resistance due to a plaque that builds up in the blood system
    • eventual hardening of the arteries
  141. atherosclerosis
    • occurs when the plaque is fatty
    • a blood clot can later from from this and arteriole sclerosis, blood tries to get through before plaque (blood pressure is high here because it builds up) while only a small amount trickles through after plaque (low blood pressure here)
    • if this or arteriole sclerosis occurs in blood vessels to brain- it can cause stroke
    • if before pressure is so big the vessels can burst- can cause cerebral hemorrhage or stroke  if in bvs to brain
  142. Homeostasis of blood pressure by altering the cardiac output
    involves a blood pressure reflex
  143. baroreceptors
    • sense stretch in blood vessels
    • if you have a high blood volume and bp, this will increase the stress in blood vessels
    • located in the carotid sinuses in internal carotid arteries and the aortic arch
    • also found in large arteries in the neck and chest
  144. sinus
    a dilation in a blood vessel
  145. carotid arteries
    go to the head
  146. aortic arch
    part of the aorta that arches around in the chest
  147. If there is a increase in bp… (homeostasis- cardiac center of medulla)
    • 1. Baroreceptors stimulated by high bp +impulses travel to medulla oblongata
    • 2. Inhibitory center stimulated- sends parasympathetic impulses in vegas nerve to heart
    • 3. Heart rate decreases, therefore cardiac output decreases, blood volume then decreases and bp decreases returning to homeostasis
  148. If you have a low bp.. (homeostasis- cardiac center of medulla)
    impulses in the medulla go to the acceleratory center, stimulate sympathetic impulses which increase heart rate, cardiac output, blood volume and then blood pressure returning it to homeostasis
  149. Maintaining blood pressure by affecting the blood vessels
    • medulla oblongata also has vasomotor center which regulates the blood vessel diameter, esp arterioles
    • -->sympathetic impulses to the smooth muscle will cause constriction of the blood vessels making a more narrow vessel and maintaing vascular or vasomotor tone
    • --> norepinepherine is the neurotransmitter
  150. if constriction is too high… (maintaining bp by affecting bvs)
    we want to dilate the bvs and inhibit constriction
  151. Blood pressure reflex (vasomotor center of medulla)
    if you have high bp, baroreceptors sense this and send impulses to the medulla and inhibit the vasomotor center causing a reflex dilation of the blood vessels (they become wider) causing a drop in bp (bc you have more space in bvs) and you return to homeostasis
  152. Higher brain centers
    • the cerebral cortex and hypothalamus can influence the medullary centers (both cardiac and vasomotor)
    • ex: in stress- impulses can go to medulla to speed heart
    • ex: varying needs in the body such as body temp (measured by hypothalamus), exercise, respiratory factors (such as low o2 level)
  153. hormones effects on blood vessel constriction and dilation- adrenal medulla
    • epinepherine
    • norepinepherine
  154. epinepherine- effect on bv constriction
    • increases cardiac output
    • tends to be a vasoconstrictor with a few exceptions
  155. when is the exception where epinephrine is a vasodilator
    increased blood flow to heart and skeletal muscle and blood vessels at these muscles dilate (shunting of blood so you can for ex run faster)
  156. Norepinepherine- effect on bv constriction
    always a vasoconstrictor
  157. hormones that increase the blood volume and bp by retaining fluids in the blood and not excreting them through the kidney
    • antidiuretic hormone (made in hypothalmus)
    • aldosterone (made by adrenal cortex)
    • these hormones are faso constrictors in times of hemorrhage (large blood loss) bc they will try to maintain bp and keep blood in the body
  158. hormones that decrease the blood volume and pressure by excreting fluid in the urine not keeping it in the blood
    • these are vasodilators, they decrease blood pressure and make more room in vessels
    • atrial natriuretic hormone- made by heart
  159. Exchange of substances at the capillaries (specifically h2o flow out of capillary into tissue and into cap from tissue)
    • by arteriole: bp is higher than osmotic pressure so H2O flows out into tissues
    • near venule end: blood pressure is lower than osmotic pressure and water is attracted to solutes in blood so flows along the gradient from tissues into capillaries.
  160. blood pressure (compared to osmotic)
    • hydrostatic pressure- due to the volume of fluid, a physical pressure
    • high pressure pushes h2o out of capillary into tissue
  161. osmotic pressure
    • due to the plasma proteins in the blood (esp albumin- most abundant)- more solutes makes water flow from tissues towards them in the capillary membrane
    • these proteins are too large (colloids)to get out of the capillary so H2o diffuses in- colloidal osmotic pressure
  162. Lymphatic system components
    • lymphatics or lymphatic vessels
    • lymph
    • lymphoid tissues and organs
  163. lymphatics
    • like veins but thinner and have more valves
    • circulation through them is like through the veins but with pulmonary and muscular pumps
    • collect excess fluid and protein from tissues and return them to venous blood (lymph empties into subclavian veins)
  164. lymph
    clear interstitial fluid in the lymphatics
  165. lymphoid tissues and organs
    concerned with defense against diseases and foreign cells
  166. lymphatic capillaries
    • blind ended- no arteriole end like in reg capillaries, pouch instead of arteriole end
    • these empty into larger lymphatic vessels which empty into the main lymphatic trunks which empty into subclavian veins
  167. main lymphatic trunks
    right lymphatic ducts and thoracic ducts