Biology 2213         Review Sheet for Test #1    Dr. James Adams

Chapter 17: Blood -- a Connective Tissue
     Matrix (plasma): 55% of blood volume (with dissolved fibrous proteins)
     Cells: 45% of blood volume, almost all RBC's (<1% WBC's & platelets)

Functions:
         I. Distribution -- O2, nutrients, nitrogenous wastes, hormones
         II. Regulation -- body heat, fluid volume, pH
         III. Protection -- Platelets (blood loss), WBC=s, antibodies, complement

Matrix -- Plasma: 90% water, 10% Solutes (Table 17.1, pg. 644)
          Electrolytes: inorganic ions -- sodium and associated chloride, many others
          Nitrogenous substances:  urea and others, mostly waste products
          Nutrients
          Gases: CO2 (mostly as bicarbonate ion), not much O2 since most is inside RBC's
          Hormones
          Plasma proteins (8% by weight):  albumins (for osmotic balance), transport proteins,
                antibodies, fibrinogen (inactive form of fibrin for clots)
      Osmolarity of plasma quite constant.

Formed ElementsAll come from stem cells (hemocytoblasts) in red bone marrow
        Called formed elements because only leukocytes are complete cells
  I. Erythrocytes (red blood cells, RBC=s) -- carry O2 (attached to Hb) 
            lack all organelles, including nucleus and mitochondria (makes sense -- why?);
            hemoglobin (Hb) makes up 33% of cell mass; spectrin in membrane makes cells pliable
            size and shape contribute to exchange of gases, including the 20% of CO2 they carry
            approx. 5,000,000 RBC's/microliter of blood (major contributor to viscosity of blood)
          Hemoglobin:  4 globin subunits, each with an Fe containing heme group (porphyrin ring)
                Each RBC contains 250,000,000 Hb; one cell can therefore carry 1 billion O2
      Production (hematopoiesis): 15 days in red blood marrow (where in adults?); released and  
            mature in two days (from reticulocytes); production/destruction remarkably constant
            (two million per second turnover).  SEE Fig. 17.5, pg. 647.
         Hormonal regulation (erythropoietin [from kidney -- WHY?], testosterone); nutrients
            required for produciton (organics, iron, B-vitamins).  Since production is so rapid, B12
            vitamin deficiency often first indicated by reduced RBC procution (pernicious anemia)
      RBC's in turn destroyed in spleen/liver/ bone marrow (100 - 120 day lifespan).  Hb turnover   
            rapid as well -- iron must be stored/transported (ferritin/transferrin) for reuse; rest of 
            heme destroyed and eliminated (released in bile [bilirubin] into small intestine); globin
            A.A.'s reused.
     RBC disorders: Anemias (know pernicious, sickle-cell), polycythemia (blood doping)
  II. Leukocytes (white blood cells, WBC=s) -- major immune system cells; production
            (of some) dramatically increases with infection/injury
        Types: (Most to least numerous: N, L, M, E, B) -- recognize these for lab practical
                    Will discuss these in much greater detail in the Immune system chapter (21)

            A. Granulocytes
                1. Neutrophils (PMNL's): active bacterial and fungal phagocytes
                2. Eosinophils: respond to allergens (inflammation) and macroendoparasites
                3. Basophils (& mast cells): release histamines/heparin
            B. Agranulocytes
                1. Lymphocytes: T- mature in thymus; attack virus-infected/tumor cells
                                          B- produce antibodies
                        These cells are SPECIFIC; with each individual attacking a very specific
                               invader; different invader, different lymphocytes
                2. Monocytes: become macrophages ("big eaters") upon leaving the bloodstream
       Production (leukopoiesis): in red bone marrow; hormonal control:  colony-stimulating  
            factors (CSF=s) released by several cell types (mainly other WBC's - why?); granulo-
            cytes stored in red bone marrow, short life-spans; agranulocytes in lymphoid tissues,
            with long life-spans. Must know myeloid and lymphoid stem cells, and which WBC's
            come from them.  SEE Fig. 17.11, pg. 655.
       WBC disorders: Leukemia (cancerous), mononucleosis (viral)
  III. Thrombocytes (platelets [not true cells]) -- fragments of megakaryocytes; form platelet 
            plug during clotting (to be discussed, below)
        Production: thrombopoietin (produced by the liver).  SEE Fig. 17.12, pg. 657. 

     Hemostasis/Maintenance of blood flow (stoppage of blood flow through wound)
        Three Steps:                   NOTE: chemicals you need to know are in BOLD
            1. vascular spasms -- damaged blood vessels constrict; normal response of smooth
                    muscle in vessel walls, and response to several chemicals (see below)
            2. platelet plug formation -- intact endothelial cells normally release NO and prostacyclin
                    that prevent platelets from sticking; however, platelets stick to damaged tissue edges,
                    and, in turn, release a number of chemicals themselves (see below), which induce
                    more platelets to stick (ADP and thromboxane); chems. also promote a wide
                    variety of other clot enhancing phenomena, including vascular spasms
                    (thromboxane) and coagulation.                     
            3. Coagulation (clotting) -- cascade of events (pgs. 658-659), several steps involve Ca+2
                    Vitamin K involved in making several clotting proteins in the liver.
        Two pathways:  intrinsic, involving PF, and extrinsic, involoving TF -- see Fig. 17.14, pg. 659.
        Both feed into common pathway:  Prothrombin activator --> (pro-)thrombin -->
            fibrin(-ogen)

        Complete in 3-6 minutes.
    Clot Retraction: platelets contract (actin/myosin); pull edges of wound together
    Fibrinolysis: tissue-plasminogen activator --> plasmin(-ogen).  Interestingly, thrombin can also
            activate plasminogen; will explain in class.
    Prevention of undesirable clottingantithrombin, heparin -- found on endothelial cells
    Healing: Platelet derived growth factor (PDGF)

     Hemostatic disorders:
        1. Thromboembolic disorders: persistent clots (thrombus, embolus)
        2. Bleeding disorders: Thrombocytopenia (reduced platelet #), liver damage, hemophilia


Transfusions and Blood Groups
: A/B Antigens (agglutinogens) and anti-A & anti-B.  Table 17.4. 
        antibodies (agglutinins; unique because they are produced without exposure to antigens)
                Blood types; who is universal donor/acceptor, and why?
            We will do a lab on blood typing
        Rh blood groups
        Volume expanders

Diagnostic Blood tests:  blood is the most frequently tested tissue of the body -- WHY?

Chapter 18: Heart A & P
     Heart (the transport system pump); in mediastinum

  ANATOMY:  See also "Circulatory System Structures -- to know" sheet for lab
        Landmarks:  Apex/base; ant/post interventricular sulci; atrioventricular (coronary) sulcus
        Coverings: visceral (epicardium)/parietal pericardium (serous); fibrous pericardium.
        Heart Wall: epicardium (as above)/mycardium with elastic CT skeleton/endocardium
            (simple squamous)
      Chambers, valves and associated vesselsKnow right and left atria and ventricles; interatrial
            septum with fossa ovalis, interventricular septum; fossa pectinate muscles (in atria),
            trabeculae carneae with papillary muscles/chordeae tendineae in ventricles; superior/inferior
            vena cavae (entering R atrium), pulmonary trunk (exiting R ventricle), pulmonary arteries
            and veins (entering L atrium), aorta (exiting L ventricle); atrioventricular [tricuspid (R) and 
            bicuspid (mitral) (L)] valves, semilunar [pulmonary (R) and aortic (L)] valves

      Systemic/pulmonary circuits (know where oxygenated and deoxygenated)
           ( Simplified diagram of flow )  (will be handed out in class)

     Cardiac circulation: Arteries-- right coronary artery, and its branches: marginal and posterior 
        interventricular artery (in posterior interventricular sulcus); left coronary artery, and its 
        branches; anterior interventricular (in anterior interventricular sulcus) and circumflex artery.
        Veins -- Great and middle (draining anterior and posterior respectively), which feed into
        coronary (cardiac) sinus, which, in turn, empties into R atrium

PHYSIOLOGY: Cells called fibers -- they tend to branch and all form intercalated disks with
        numerous gap junctions (heart a functional syncytium); contain lots of mitochondria. Difs.
        from skeletal muscle: some cardiac cells autorhythmic, heart contracts as a unit; no tetanic
        contractions in heart muscle (long refractory period); heart almost exclusively aerobic
    Membrane potential (from chap 2); Na+, K+, Cl-, A.A.-; action potential (from chap 11)
         Cardiac muscle contraction: ("fast") Na+ channels involved, as is typical for AP, but "slow"
            Ca+2 channels also involved (Ca+2 also enters from extracellular fluids), increases
            refractory period; makes tetany virtually impossible.  Actual contraction typical of
            muscle -- Ca+2 release from SR, binds to troponin . . . (as in chap 9)
         Intrinsic conduction system: autorhythmic cells-- use fast Ca+2 channels for depolarization
            sinoatrial (SA) node (the pacemaker); atrioventricular (AV) node (delays impulse so
            atria contract before ventricles) -- see Fig. 18.13, Page 687:  AV node
            feeds into AV bundle, R & L bundle branches, and subendocardial conducting network

            (Purkinje fibers) distribute impulse to walls of ventricles synchronously, with papillary
            muscles contracting just ahead of rest of ventricles to tighten chordae tendineae.   
            Nodal system determines synchronicity of heartbeat

 Modifying the basic rhythm:
   External (ANS, hormonal) stimulation required to accelerate/decelerate heart rate (H.R.)
        Cardiac centers in medulla oblongata  -- see Fig. 18.14, page 688.
        Sympathetic nervous system (including adrenal gland):  release norepinephrine (also 
            called noradrenalin) -- speeds H.R.
        Parasympathetic (mainly vagus nerve): releases acetylcholine -- slows H.R.
   Cardiac cycle: systole and diastole, with associated heart sounds (valves); know basic
        sequence of events (pgs. 693 - 696)
 
   Cardiac output (C.O.): (stroke volume)  x  (heart rate)     [S.V. x  H.R.]
        Regulation of S. V.:  preload and the Frank-Starling Law, contractility, afterload
        Regulation of H. R.: autonomic nervous system controls (as above, hormonal controls
            (thyroxine, epinephrine), ions, physical factors (age, gender, etc.). All, of course,
            influence blood pressure as well.*  (see below)
        C.O. remains remarkably consistent throughout adult life (avg. of 5.25 l/min.), which
            means anything that changes either S.V. or H.R. will inversely affect the other.

Chapter 19: Vessels
         60,000 miles of vessels in the body; arteries/veins just conduits, exchange in capillaries

  Walls of vessels three-layered:
        1. tunica intima (interna) -- endothelium (simp. squam.); slick, continuous with endo-
                cardium; sparse conn. tissue basement membrane
        2. tunica media -- circularly arranged smooth muscle, w/vasomotor nerve fibers, and  
                elastin fibers; partly regulates blood flow/pressure (vasodilation/-constriction);
                thickest in big arteries, non-existent in capillaries/small veins, thinner and ill-defined
                in larger veins
        3. tunica externa (adventitia) -- loosely woven collagen with nerves; thickest in large
                veins. Contains networks of smaller vessels, the vaso vasorum, which branch into
                tunica media as well.
  Arteries: carry blood away from the heart
        1. Elastic (conducting)-- large lumen; closest to heart; withstand large pressure fluctuations,
                 and act as auxilliary pumps; arterial pulse
   
     2. Muscular (distributing) -- small to medium-sized; carry blood to specific organs
        3. Arterioles -- diameter <0.3mm down to 10 microns; smaller lose tunica externa; fine
                control of blood flow here
  Capillaries: 8-10 microns (barely bigger than diameter of RBC); tunica intima (endothelium) only
        1. Continuous capillaries -- blood-brain barrier; skin; muscles, etc.. Numerous pinocytotic
                vesicles.
        2. Fenestrated capillaries -- pores increase permeability; mucosa of intestine, glomerulus in
                kidney; hypothalamus; many other places.
        3. Capillary sinuses -- sluggish flow allows cleaning by special phagocytes
    Thoroughfare channels and capillary beds,
with numerous precapillary sphincters

  Veins: Low pressure; have very important one-way valves
        1. Venous sinuses -- flattened endothelium only (intracranial [dural sinuses], coronary)
        2. Venules -- no tunica media, except in largest; shunt blood to veins
        3. Veins -- all layers (tunics), but thinner than arteries (particularly media), with larger
            lumen than arteries; up to 65% of blood in veins at one time (blood reservoirs)
    Because of low pressure, have modifications to aid in blood movement (see below*)
            one way valves, large lumen (low resistance), respiratory/muscular "pumps"
        Varicose veins
   Vascular Anastomoses -- more common between veins

Physiology of Circulation: blood flow -- from high to low pressure areas, flow velocity (rate),
            blood pressure, resistance -- know definitions; relationship: F = ΔP/R
      Resistance: influenced by blood vessel diameter and length, and viscosity; the only regulated
                one of these is the diameter.  Resitance is greatest in small diameter vessels (most
                friction), especially arterioles and capillaries hence, most resistance peripheral (P.R.)
      Systemic blood pressure (B.P.): greatest at heart, highest at systole (lower with diastole), 
                declines further from heart, near zero at vena cavae -- pressure gradient
               
(see fig. 19.7, pg. 716)
            *Factors aiding venous return: B.P. gradient, valves, muscular/respiratory pumps, mild
                venoconstriction (with sympathetic stimulation)

    *Maintaining B.P.: regulation of cardiac output (see above), blood volume, P.R.
    Regulation of B.P.: anything that influences the above factors influence B.P.
        I. Short Term controls   
            A.  Neural controls: sympathetic/parasympathetic stimulation
                1.  The cardiovascular/vasomotor centers in the medulla -- vasomotor tone
                2.  Baro-(presso-)receptor reflexes -- carotid and aortic
                3.  Chemoreceptors responding to various chemicals -- CO2 & pH (& O2)
                4.  Higher brain centers (emotional influences, etc.)
            B.  Hormonal controls:  adrenal hormones ([nor-]epinephrine), ANP, ADH, NO
        II.  Long Term controls: largely involve changing volume of blood
            A.  Renal regulation:
                1.  Direct mechanism
                2.  Indirect mechanism: involves renin/angiotensin/aldosterone
                        Further involves, as you would expect, ADH from above
For summary of effects of different factors on smooth muscle in the walls of blood vessels, see
     Fig. 19.16, page 727.

      Blood Flow to special areas (specific organs); at rest/during exercise (Fig. 19.15, pg. 726)
            autoregulation:  
                metabolic controls: concentration of various substances in blood -- CO2 , H+ (& O2),
                    adenosine.  Involves NO or endothelin release from endothelium
                myogenic controls:  Fast flow results in stretch of tunica media and automatic constric-
                    tion response of smooth muscle cells; slow flow results in opposite response.
           Different regional flow: skeletal muscle, brain, skin, lungs, heart, kidneys

      Flow rate (velocity): (see Fig. 19.18, pg. 730) fastest in large arteries, slowest in capillaries
         (largest cross-sectional area), faster again in veins.  This is exactly what you would want --
        WHY?

     Capillary fluid dynamics: fenestrated capillaries; SEE pgs. 732-733.
        involves hydrostatic pressure (on plasma) forcing fluid out at arteriole end of capillary bed
        and (colloid) osmotic pressure (due to concentrated plasma solutes [particularly albumins]
        left behind) pulling fluid back in at the venule end of the cap. bed, resulting in a Net Filtration
        Pressure (NFP) that is outward at the arteriole end and inward at venule end of the capillary
        bed. Not all fluid leaving a fenestrated cap bed at arteriole end returns at venule end --
        explains need for another fluid "pick up" system -- the Lymphatic system (the next chapter
        and on the next test!).

(Circulatory pathways:  Pages 736 - 758.  You will find out in lab which specific vessels
    you will need to know for lab practical)