BIOL 67B Test 2
How is the blood brain barrier created?
-Blood Brain Barrier --CNS capillaries do not have intercellular channels --Joined by tight junctions --Brain cannot obtain filtering processes: must use diffusion, active transport, endocytosis --Extremely specific --Criteria for treatment of disease
Know the normal value for blood immorality, blood pH, and crematoria (both female and male)
-Blood Osmolality: 280-296 mOsm -Blood pH: 7.35-7.45 -Hematocrit -Female: 37-48% -Male: 45-52%
Describe the formation of lymph
-Capillary beds: osmotic and BP components --Starling forces -Net result: fluid in tissues -Retrieval mechanism: fluid enters blind lymphatic capillaries -Lymph content: interstitial fluid, lymphocytes, macrophages
Describe the anatomy of a lymphatic vessel
-Walls similar to veins -Valves -Larger ducts have smooth muscle in their walls -Skeletal muscle pumps
What is contained in plasma? Why are Na+ and H2O concentrations so important? Why is pH balance so Important?
-Water (90%), Ions (0.9%), Proteins (8%) [hormones, enzymes, antibodies], Metabolites (1.1%) -Water balance is critical for blood pressure -Na+ is major solute in plasma -Increase in concentration (ingestion, loss of water) creates osmotic issues -ADH and renin-angiotensin-aldosterone -pH is critical for proteins, PM function etc. -Lungs, bicarbonate ion, kidney control
Myocardium
Aerobic respiration --Myoglobin --Mitochondria --Extensive circulation --Cellular respiration occurs when heart isn't contracting -Striated -Short, branched -Involuntary -Intercalated discs --Syncytium
What causes clots to dissolve in the body?
Clot Retraction -The drawing away of the clot from the wall of a vessel, a stage of wound healing caused by contraction of platelets -Fluid squeezed from clot as it retracts is serum -Problem? Internal clots... Clot Dissolution -Factor XII causes activation of Kallikrein -Kallikrein catalyzes conversion of plasminogen to plasmin -Plasmin hydrolyzes fibrin
Circulatory System Components: Protection Components
Clotting: platelets and plasma clotting factor Immunity: leukocytes
What are the two semilunar valves: their location, function, and characteristics.
Pulmonary semiulnar valve Atrial semiulnar valve
What is the pulmonary circuit?
Pulmonary trunk and veins and function is gas exchange in lungs
1. Ventricular systole 2. Depolarization (of ventricles) propagates across septum, down septum to apex, and around ventricular walls toward base 3. Repolarization of atria is masked
QRS Complex
Circulatory System Components: Transportation Components
Respiratory gases: erythrocytes for O2; bicarbonate for CO2 Nutrient Molecules: plasma; protein carriers Excretory molecules: plasma
What is an agglutination reaction? Why does it occur? In the test for blood types which antibody reacts with which antigen?
Agglutination Reaction: -Antibodies produced against alternate antigen without prior exposure -RBCs will stick together due to antigen-antibody binding -Agglutination will occur when antigen-antibody complex is formed
What are thrombocytes and why are they important?
Aka "Platelets" -Fragments of megakaryocytes -No nuclei -Amoeboid -5-9 days Importance... -Clotting -Serotonin -Mass of clot
What are the plasma proteins and what are their functions?
Albumin (60%): major contributors to osmotic concentration of plasma; transport lipids, steroid hormones -Liver, osmotic effect, viscosity Globulins (35%): transport ions, hormones, lipids; immune function -Alpha: liver, transport -Beta: liver, transport -Gamma: lymphocytes, antibodies Fibrinogen (4%): essential component of clotting system; can be converted to insoluble fibrin -Liver, clotting
What does a reduced ejection fraction mean?
- Measure of the heart's efficiency - Proportion of the EDV that is ejected against a given afterload - The percentage of blood ejected from the ventricle with each heart beat - 50% indicates that the ventricle ejects have its volume each time it contracts - A normal, at rest ejection fraction is approximately 60% A reduced ejection fraction indicates that cardiomyopathy is present (heart disease that has various symptoms)
What characterizes anemias? How do we divide anemias clinically (three ways)? Know the terms for size and color of the rbcs.
Anemia -Over 400 types --Decrease in hematocrit or malfunction of Hb -Divided clinically into 3 groups based on causes --Blood loss --Decreased of faulty blood cell production --Blood cell destruction RBC Color -Hypochromic: pale color -Normochromic: normal color -Hyperchromic: dark color RBC Size -Microcytic: small size -Normocytic: normal size -Macrocytic: large size
Know the structure of blood vessels and the functions of the different tunica layers. Why would an artery have an elastic layer?
Artery would have elastic layer due to blood pressure, blood moving away from heart. Sometimes more blood is pumped out due to environmental changes, so arteries need to be able to adapt to BP change Arteries would have a muscular layer to increase resistance to blood flow?
What is the term used for production (formation) of the formed elements of blood? What is the hormone that stimulates RBC production and where does it originate? What triggers erythropoiesis?
Hemoatopoeisis -Hormone that stimulates RBC production: erythropoietin --Secreted by kidneys when O2 levels are decreased -Triggers for Erythropoisesis --Reduced RBC count (blood loss, RBC destruction, decreased production) --Insufficient Hgb (anemia, e.g., iron deficiency) --Reduced [O2] (high altitude, disease states)
What are the granular and agranular leukocytes and what are their characteristics and functions?
Leukocytes (WBCs) Granular Leukocytes Short life span (12 hours to 3 days) ENSINOPHILS BASOPHILS NEUTROPHILS (most numerous, 54-62%) Agranular Leukocytes Life span 100-300 days LYMPHOCYTES (25-33%) MONOCYTES
Describe the anatomy of a lymphatic trunk.
Lymphatic Trunks -Superficial lymphatics --Hypodermis --Parietal and visceral peritoneum, pericardium, and pleura --CT of mucous membranes in digestive, respiratory, urinary and reproductive systems Dee Lymphatics -Jugular trunks -Subclavian trunks -Bronchomediastinal trunks -Intestinal trunks -Lumbar trunks
Circulatory System Components: Lymphatic System Components
Lymphatic vessels and nodes. Lymphoid Organs
What causes lymphedema?
Lymphedema is recognized as an accumulation of interstitial fluid that occurs due to interference with lymph drainage in a part of the body. Interstitial fluid increases, and the affected area both swells and becomes painful. If lymphedema is left untreated, the protein-rich interstitial fluid may interfere with wound healing and can even contribute to an infection by acting as a growth medium for bacteria.
What is a hematocrit?
Measurements of the amount of formed elements in total blood volume, Plasma 55%---> Buffy Coat----> Formed Elements (45%) (RBCs)
Why is most of the blood volume in the veins, and how is blood returned to the heart in this low pressure system?
Most blood volume is in the veins because veins do not have a strong pump to push blood back towards the heart. Veins have valves, skeletal muscle contractions and respiratory pumps in order to return blood back to the heart.
1. Phase 1: atrial systole begins 2. SA Node initiates depolarization of atrium 3. Transmission of stimulus: internodal tracts to AV node and Bachmann's Bundle to left atrium 4. Note change in direction as spread of summation of depolarization changes vectors between leads
P Wave
1. Atrial systole completes 2. No vector changes (summation is equal) 3. Stimulus transmitted across AV bundle and down bundle branches
PR Segment
What is the pericardial cavity? The pericardium?
Pericardial cavity: contains serous fluid for buoyancy Pericardium: visceral and parietal layers, parietal is reinforced by dense, irregular connective tissue, fibrous pericardium
What are Starling forces? What do they mean in terms of water balance?
Four Forces: 1. Hydrostatic pressure in the capillary (Pc) 2. Hydrostatic pressure in the ISF (Pi) 3. Oncotic pressure in the capillary (pc) 4. Oncotic pressure in the ISF (pi) -Calculate net driving pressure: --(Pc +pi) - (Pi +pc) --Fluid out - fluid in -Regulation of fluid balance across capillary membranes
What is the Frank-Starling law and why does it affect contractility?
Frank Starling Law: strength of ventricular contractions varies directly with the end diastolic volume At the end of systole, sarcomere length is short Contractility: the strength of contraction at any given sarcomere length (increases with increased length)
What is (are) the homeostatic function(s) of the lymphatic system?
Functions: -Return excess tissue fluid to the cardiovascular system -Absorption of lipoprotein from the gastrointestinal system -Immunological defense component Lymph -Capillaries: closed ended with porous junctions between endothelial cells -Excess interstitial fluid, proteins, microorganisms, absorbed fat (intestines)
What causes heart murmurs?
Heart Murmur: abnormal heart sounds, indicative of valve problems, hole between the atria to add hissing sound
Circulatory System Components: Cardiovascular System Components
Heart: Double pump with four chambers and pulmonary (gas exchange) and systemic circulation (somatic vessels)
What is stroke volume?
the amount of blood pumped by the left ventricle of the heart in one contraction, usually 2/3 of the amount of blood in the third ventricle is expelled with each beat
What is the tetrology of Fallot and what sound would it make?
Tetralogy of Fallot: defect of the septum between the ventricles, causing deoxygenated blood to mix with oxygenated, being sent out to the body Four aspects 1. There is a ventricular septal defect 2. There is narrowing of the valve leading to the pulmonary arteries (pulmonic stenosis) 3. The aorta "overrides" the ventricular septal defect 4. There is thickening (hypertrophy) of the right ventricle -Sound crescendo and decrescendo between S1 and S2
What are the functions of the RBCs? What are the characteristics of RBCs? Why are rbcs shaped the way they are and why don't they contain mitochondria? What is their main solute content?
Red Blood Cells aka "Erythrocytes" -No nuclei -No mitochondria (mitochondria produce ATP by use of O2, and RBCs main function is to transport O2) -Short life span (120 days) -Biconcave discs create high surface area ----Gas exchange -Shape maintained by cytoskeletal network (mostly spectrin) -Flexible (fit through capillaries) Main solute content: Hemoglobin
What factors influence blood flow?
Regulation of blood flow -Vasoconstriction --Sympathetic, NE & a --Ca++ -Vasodilation --Parasympathetic, Ach & M --GPCR beta gamma subunit --Opening K+ channel inhibits
How are old rbcs removed from circulation? What happens to the toxic iron in hemoglobin? What is bilirubin?
Removed from circulation by phagocytic cells in spleen, liver, and bone marrow Either ruptured when they enter narrow capillaries or macrophages engulfs them as they pass the spleen Spleen destrosy old RBC and converts Hb to bilirubin Bilrubin -Broken down heme molecule from hemoglobin -Carried by plasma protein albumin -Yellow compound -Secreted in the urine
Major Branches of the Coronary Circulation
Right and Left Coronary Artery
What are the two atrioventricular valves: their location, function, and characteristics.
Right atrioventricular valve aka "tricuspid valve" Left atrioventricular valve aka "bicuspid valve" or mitral valve 1. Open and close with pressure gradients 2. Papillary muscles 3. Open when blood flows from atrium to ventricles 4. Close when blood fills the ventricles to prevent backflow
What are the components of the conduction system of the heart? What is the function of the SA node and where is it located? The AV node? What are the three pacemaker regions and their rhythm?
SA node -Primary pacemaker (70-80 bpm) -Internodal Tracts & Bachmann's Bundle AV node -Secondary pacemaker (40-60 bpm) AV bundle R & L bundle branches Purkinje fibers Tertiary pacemaker (30-40 bpm) Flow of electrical charge SA node → internodal tracts & bachmann's bundle → AV node → AV bundle (R & L) → Purkinje Fibers
1. Ventricular systole is completed 2. Depolarization equal in all directions so no deflection of tracing
ST Segment
Know the drainage patterns (what drains into it, where does it empty into) for the R lymphatic duct and the thoracic duct.
Thoracic duct -Cisterna chyli at base --Right and left lumbar trunks --Intestinal trunks -EMPTIES INTO LEFT SUBCLAVIAN VEIN Right Lymphatic duct -EMPTIES INTO RIGHT SUBCLAVIAN VEIN
Know the components and functions of the circulatory system and the lymphatic system
Vascular Circuits Pulmonary --Pulmonary trunk and veins --Function is gas exchange in lungs Systemic Aorta and venae cava --Carotid, subclavian arteries and veins --Mesenteric arteries, hepatic portal vein, hepatic vein --Renal arteries and veins --Iliac arteries and veins Function is to transport blood to and from the body Coronary --Right and left coronary arteries and veins --Function is to provide blood for the heart muscle
What regulates EDV?
Venous return to the heart controls End-diastolic volume (the final volume in ventricles just before the heart contracts) Depends on venous pressure
What are the dietary requirements for Hematopoiesis? Leukopoiesis?
-Amino acids, lipids, carbohydrates -Iron (toxic, so stored in protein-iron complexes) --Ferritin, hemosiderin (intracellular) --Transferrin (blood plasma) -B-complex vitamins (assist DNA synthesis) --Vitamin B 12 --Folic acid Leukopoiesis -Formation of WBCs -Occurs in both myeloid tissue and lymphoid tissue
What is the coronary circuit?
-Aorta and Vena Cava --Carotid, subclavian arteries and veins --Mesenteric arteries, hepatic portal vein, hepatic vein --Renal arteries and veins --Iliac arteries and veins -Function is to transport blood to and from the body
Describe the anatomy of a lymphatic capillary
-Blind ended -Thin walls with incomplete basal lamina -Endothelial cells overlap --One way valve for ISF --Anchoring filaments -Trap for ISF
How is microcirculation controlled?
-Blood flow dependent on --Resistance in arterial network --Autoregulation (oxygen, metabolites) --Hormonal --ANS (vasoconstriction and vasodilation) -Precapillary sphincter --ANS (vasoconstriction and vasodilation) -Arteriovenous anastomoses (metarterioles)
What structures drive/hold fluid in the lymphatics? What contents are present in lymph?
-Fluid and proteins escaping from vascular capillaries is collected by lymphatic capillaries --Vessels --Trunks --Ducts -Respiratory and muscular pumps promote flow of lymphatic fluid -Lymphatic ducts empty into subclavian veins
Basophil Function
-Inflammatory response -Release of histamine -Affinity for hematoxylin stain -Blue color
Monocyte Function
-Largest leukocyte -Phagocytic (macrophage) -Horse shoe shaped nucleus
Eosinophil Function
-Phagocytize antigen-antibody complex -Secretes enzymes for dissolution of clots -Response to parasitic infection -Affinity for eosin stain -Red/orange color
Neutrophil Function
-Phagocytize pathogens -Little affinity for eosinic r hematoxylin stain -Polymorphonuclear leukocytes (PMNs) -Pale lavender color
What causes arteriosclerotic plaques (make sure you understand the process, not just the molecule) and why are they significant?
-Plaques of cholesterol, deposited by LDL, form atheromas (usually at branch points) -Site of fibrous plaque may serve as site for thrombus -Smoking, hypertension, high blood cholesterol, diabetes contribute to this
What is the significance of the precapillary sphincter?
-Precapillary sphincters are the smallest arteries -Control blood flow through smooth muscle -Littler to no tunica externa
What is the systemic circuit?
-Right and left coronary arteries and veins -Function is to provide blood for the heart muscle
Describe the anatomy of a Lymphatic Ducts
-Similar to veins -Three layers -Valves -Smooth muscle peristalsis moves lymph --Pacemaker action potential increased by stretch of duct
Lymphocyte Function
-Specific immunity (B-cell) antibody production -Cell mediated immunity (T-cell) -Large circular nucleus and small ring around
What is the cisterna chyli, where is it located, and what is its function?
-The cisterna chyli gets its name from the milky, lipid-rich lymph called chyle, it receives from vessels that drain the small intestine of the gastrointestinal (GI) tract. -Both left and right intestinal and lumbar trunks drain into the cisterna chyli. The thoracic duct extends superiorly from the cisterna chyli and lies directly anterior to the vertebral bodies.
CARDIAC CYCLE
1. Repetitive pattern of contraction and relaxation in the heart 2. Systole: contraction, blood is force forward 3. Diastole: relaxation, chambers fill with blood 4. Simplistic cycle: -Atria in systole (ventricles diastole) -Ventricle in systole (atria diastole) -Both in diastole
CARDIAC CYCLE Phase 3: Rapid Ejection
1. Semilunar valves open due to increased ventricular systolic pressure
How do TPR and the Frank-Starling law affect the stroke volume differently in the right and left ventricles?
1. A rise in TPR causes a decrease in the stroke volume of the ventricle 2. The EDV is greater for the next cycle because more blood remains in the ventricle due to #1 3. The ventricle is stretched due to #2 4. #3 leads to increased contractility and greater stroke volume 5. Normal cardiac output is maintained
CARDIAC CYCLE Phase 1: Atrial Systole
1. AV Valve Opens 2. Semiulnar valve closes 3. Systolic contraction of atria adds final volume to ventricles (end-diastolic volume)
CARDIAC CYCLE Phase 6: Rapid Ventricular Filling
1. AV valves open due to pressure of venous blood 2. Both atria and ventricles fill with blood
CARDIAC CYCLE Phase 7: Reduced Filling
1. AV valves open, cardiac cycle ready to begin again
CARDIAC CYCLE Phase 2: Isovolumetric Contraction
1. All valves closed (first heart sound "lub") 2. Pressure in ventricles increases with systolic contraction
CARDIAC CYCLE Phase 5: Isovolumetric Relaxation
1. All valves closed (second heart sound "dub") as pressure in arteries exceeds that of ventricles 2. 1/3 of blood left in ventricles: end systolic volume
What are the three types of capillaries, and what functions do each serve?
1. Continuous (intracellular transport of materials) 2. Sinusoids (proteins, rbcs can pass through) 3. Fenestrated (restriction of proteins and larger molecules between capillary and interstitial fluid)
What are the factors influencing stroke volume?
1. End-diastolic volume 2. Total peripheral resistance 3. Contractility
What are the three layers of the cardiac wall?
1. Epicardium (visceral pericardium) 2. Myocardium (syncytium of cardiac muscle) 3. Endocardium (CT, endothelium)
What regulates cardiac rate? What are the different chronotropic effects and what causes them?
1. SA node sets sinus rhythm 2. NE from SNS: increase cardiac rate through Beta 1 GPCR --Opening of Na+ and Ca++ channels --Increased spontaneous depolarization --Increased firing rate (+ chronotropic) --Increased conduction rate (+ dromotropic) 3. E from adrenal medulla: increase cardiac rate --As SNS 4. Ach from PSNS: decrease cardiac rate through muscarinic M2 GPCR --Opening of K+ channels, close Ca++ channels --Decreased spontaneous depolarization --Decreased firing rate (-chronotropic) --Decreased conduction rate (-dromotropic)
What is the cause of the heart sounds? Which is first? Which is second? Which can be separated into two distinct sounds, and how can it be separated?
1. Lub sound is when AV valves close, isovolumetric contraction 2. Dub sound is when semilunar valves close, isovolumetric relaxation
What is unique about the myocardial action potentials? Why is this difference critical for heart function (think absolute refactory period and contraction of the myocardium)?
1. Once stimulated by the pacemaker, myocardial cells produce their own action potential 2. Depolarized to threshold 3. Na+ VGCs 4. Level of depolarization is maintained for 200-300 msec before repolarization --Plateau phase due to slow Ca++ channel 5. Rapid repolarization from K+ VGCs 6. Heart CANNOT SUSTAIN contractions --Long action potential --Long refractory period --No summation 7. Myocardium must relax after each contraction
What is the function of the fibrous skeleton of the heart?
1. Structural separation 2. Electrical separation 3. Annuli fibrosis (supports valve tissues, ring around the surface of the valve to strengthen valve and provide attachment point for flaps) Stabilize valves and myocardium, physical support from myocardium, distribution of forces during contraction, reinforcement of valves, fibroelastic tissue facilitates return to original shape after contraction, physical isolation of atrial myocardium and ventricular myocardium
CARDIAC CYCLE Phase 4: Reduced Ejection
1. Ventricles finish systole 2. Total ejection from phases 3 and 4 is approximately 2/3 of the blood volume in the ventricles: stroke volume
How is cardiac output measured?
1. Volume of blood pumped per minute by each ventricle 2. Measured in ml/min
Know the genotypes and antigenic components of the ABO blood types and the Rh typing system. Know which type is the universal donor and which is the universal receiver and why. Know what antigens are expressed, how one tests for the antigens, and the significance in transfusions, etc.
ABO System -Gene expression of antigenic proteins located on chromosome number 9 -Type A: only A antigen --Either IaIa or Iai -Type B: only B antigen --Either IbIb or Ibi -Type AB: A and B antigen --IaIb -Type O: neither A nor B --Ii Universal Donor: O- because it is compatible with any blood type Universal Reciever: AB+ because it can receive any type of blood
Know the hormones responsible for Na+ and H2O balance
AH and Renin-angiotensin-aldsoterone system
Circulatory System Components
Cardiovascular System, Lymphatic System, Transportation, Regulation, Protection
Know the structure of hemoglobin and the differences between oxyhemoglobin and deoxyhemoglobin. How does it function?
Hemoglobin -Iron group (heme) bound to protein globin --2 alpha subunits and 2 beta subunits --Each subunit can carry 1 O2 molecule --1 RBC can carry about 1 billion O2 molecules --Binds O2 in [hi], neutral pH (oxyhemoglobin) -Releases O2 in [lo] acidic pH (deoxyhomoglobin) Oxyhemoglobin has unique 3-D shape, high affinity for O2 Reused (deoxyhemoglobin) also has unique shape, reduced affinity for O2 Shape change determines ability to attach O2
What are the causes of hemorrhagic anemia? What happens with decreased/faulty rbc production? What is hemolytic anemia?
Hemolytic anemia: a faulty mechanical heart valve. Once rbcs pass through the fake valve, the rbcs are torn up Hemorrhagic anemia: constant loss of blood
Circulatory System Components: Regulation Components
Hormonal: plasma; protein carriers Temperature: blood vessels
What causes pernicious anemia? Iron deficiency anemia? Sickle cell? Eosinophilia? What is polycythemia and when is it normal to have it?
Pernicious anemia Caused by Vitamin B12 deficiency Can be either macrocytic hyperchromic or macrocytic normochromic Enlarged, dark red rbcs, hypersegmental neutrophil Iron Deficiency Anemia Caused by iron insufficiency (decreased hemoglobin) Microcytic hypochromic anemia Small erythrocytes (sizes also vary), large area of pallor in center Sickle Cell Anemia Caused by single amino acid substitution (valine instead of glutamic acid) in beta subunits Normochromic, normocytic anemia Sickle shape occurs in O2 deficient environment (tissues) Eosinophilia Many causes (malignancy, CT diseases, parasitic diseases, allergies) Abnormal eosinophil count (normal cells) Polycythemia Numerous causes, abnormally high counts of rbcs When you are a child it is normal because you are growing, and when you are returning from high altitudes because your body produces more RBCs when there is less oxygen levels
Name the three tonsils, state where they are located, and describe their function.
Pharyngeal -Aka adenoids -Posterior superior wall of nasopharynx Palatine (pair) -Posterior margin of oral cavity Lingual (pair) -Base of tongue
What is the composition of blood?
Plasma: Water and dissolved solutes Formed Elements: Erythrocytes, Leukocytes, and Platelets
Know how fibrinogen is converted to fibrin, understand the basics of the extrinsic and intrinsic pathways, and know the steps of the common pathway.
Platelets and damaged tissue cells release → Prothrombin Activator → Prothrombin + Ca2+ → Thrombin → Fibrinogen → Fibrin threads (RBCs are trapped among fibrin threads)
What is the function of platelets in hemostasis and what is the PRR?
Platelets attach to collagen and degranulate PRR = Platelet Release Reaction -ADP, serotonin, thromboxane A (prostaglandin) --VASOCONSTRICTION -More platelets attach, undergo PRR
What is the preload of the ventricle and how does it influence stroke volume?
Preload: the initial stretching of the cardiac myocytes prior to contraction Related to the sarcomere length STROKE VOLUME IS DIRECTLY PROPORTIONAL TO PRELOAD
What is unique about the spontaneous depolarization of myocardial pacemaker cells?
Spontaneous depolarization 1. K+ VGCs hyperpolarize 2. VGCs for Ca++ open as membrane potential becomes MORE NEGATIVE 3. Slow influx of Ca++ to -40 mV
What is the function of the annuli fibrosi?
Stabilize the left and right ventricles
Trace the blood through a human heart from the venae cavae to the aorta using the correct names for all blood vessels, atria, valves, and ventricles.
Superior/inferior vena cava or coronary sinus → right atrium → tricuspid valves → right atrium → pulmonary semilunar valve → pulmonary trunk → R and L pulmonary arteries → lungs → R and L pulmonary veins → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → ascending aorta → aortic arch → descending aorta → body
1. Repolarization begins at apex (opposite direction of QRS and flattened) 2. End of ventricular systole
T Wave
What are the three mechanisms for hemostasis? What is the sequence of events for formation of a blood clot?
Three mechanisms for Hemostasis -Vasoconstriction -Formation of platelet plug -Production of a web of fibrin In the absence of damage to the endothelium, platelets are repelled from it and each other Prostacyclin (prostaglandin) Damage to the vessel exposed subendothelial tissue collagen Von Willebrand factor (paracrine hormone) Platelets attach to collagen and degranulate Platelet Release Reaction ADP, serotonin, thromboxane A (prostaglandin) VASOCONSTRICTION More platelets attach, undergo PRR Formation of platelet plug Platelet plug is strengthened by fibrin and rbcs In arteries, blood flow may be too fast for rbcs to be trapped in clot Conversion of fibrinogen to fibrin
What are the forces that control movement of substances through the capillary wall (be specific)?
Three ways to exchange substances in the blood and interstitial fluid: Diffusion Transcytosis Bulk flow Diffusion: -Plasma proteins, rbcs do not cross in all but sinusoidal capillaries -Diffusion through --Endothelium plasma membrane (lipid soluble) --Intercellular clefts --Fenestrations -If based on diffusion --Blood to ISF to cells ---O2, glucose, amino acids, hormones --Cells to ISF to Blood ---CO2, waste products Transcytosis -Transport of large, lipid-insoluble molecules that cannot cross the endothelial plasma membrane -Enter from plasma by endothelial endocytosis and are exocytosed into interstitial fluid -Selective Bulk Flow -Filtration: fluid moves out of the capillary because of --Blood hydrostatic pressure (BP) --Interstitial fluid osmotic pressure -Reabsorption: --Blood colloid osmotic pressure (created by proteins/rbcs that stay in the capillary) --Interstitial fluid hydrostatic pressure
What is and what affects TPR (total peripheral resistance)? What is the afterload of the ventricle and how does it influence stroke volume? What effect does an increase in TPR have on cardiac output?
Total Peripheral Resistance (TPR) 1. Pressure in arterial system in diastole --Muscular arteries do not expand: resistance vessels 2. Systolic contraction causes bolus of blood which increases mean arterial pressure 3. Impedes blood flow: AFTERLOAD after ejection has begun --Ejection will cease after aortic pressure and intraventricular pressure become equal 4. Stroke Volume is INVERSELY PROPORTIONAL to afterload --An increase in TPR will cause a decrease in stroke volume
Know the common final pathway used by both the extrinsic and intrinsic clotting pathways, and know what activates each clotting pathway.
Two Pathways -Instrinsic pathway --No further chemicals needed --Occurs when collagen is exposed to plasma -Extrinsic pathway --Initiated by exposure of plasma to negatively charged surface --Factor XII (protease) is activated --Cascade of enzymes is activated -Both pathways merge to form a common pathway for the final steps of conversion Platelets and damaged tissue cells release → Prothrombin Activator → Prothrombin + Ca2+ → Thrombin → Fibrinogen → Fibrin threads (RBCs are trapped among fibrin threads)
What controls the extrinsic regulation of contractility?
Two effects of sympathoadrenal system: -Positive inotropic defect --For a given sarcomere length, the contractility varies directly with sympathoadrenal stimulation -Positive chronotropic effect
Know how the pH of blood is maintained for homeostasis
pH balance is critical for proteins, PM function lungs, bicarbonate ion, kidney control
What is cardiac rate?
the speed of the heartbeat measured by the number of contractions of the heart per minute. --CO ml/min + SV ml/beat x CR beat/min
