Biology 2213         Review Sheet for Test #2    Dr. James Adams

Chapter 17: Blood -- a Connective Tissue
     Matrix (plasma): 55% of blood volume (with dissolved fibrous proteins)
     Cells (formed elements): 45% of blood volume

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

Matrix -- Plasma: 90% water, 10% solutes (wide variety, including albumins; KNOW
    Table 17.1, pg. 633); osmolarity quite constant.

Formed ElementsAll come from stem cells (hemocytoblasts) in red bone marrow
  I. Erythrocytes (red blood cells, RBC=s) -- carry O2; lack all organelles, including nucleus;
            hemoglobin (Hb) makes up 33% of cell mass; >95% of formed elements (major 
            contributor to viscosity of blood).  Hematocrit.
      Production (hematopoiesis): in red blood marrow (where in adults?); mature in 3-5
            days (from reticulocytes); production/destruction remarkably constant (two
            million per second turnover)
         Hormonal (erythropoietin [from kidney -- WHY?], testosterone) and nutrient
            (organics, iron, B-vitamins) requirements for production.
      RBC's in turn destroyed in spleen/liver/ bone marrow (100 - 120 day lifespan).  Hb   
            turnover rapid as well -- iron must be stored/transported for reuse; rest of heme
            destroyed and eliminated.   
     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
            A. Granulocytes
                1. Neutrophils: active bacterial and fungal phagocytes
                2. Basophils (& mast cells): release heparin/histamines
                3. Eosinophils: respond to allergic inflammation and macroendoparasites
            B. Agranulocytes
                1. Lymphocytes: T- mature in thymus; attack virus-infected/tumor cells
                                          B- produce antibodies
                2. Monocytes (macrophages)
       Production (leukopoiesis): in red bone marrow; hormonal control:  colony-stimulating  
            factors (CSF=s) released by several cell types; granulocytes 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.
       WBC disorders: Leukemia (cancerous), mononucleosis (viral)
  III. Thrombocytes (platelets [not true cells]) -- fragments of megakaryoblasts; form platelet 
            plug during clotting (to be discussed, below)
        Production: thrombopoietin (produced by the liver)

     Hemostasis/Maintenance of blood flow (stoppage of blood flow through wound)
        Three Steps:
            1. vascular spasms -- damaged blood vessels constricts, for several reasons
            2. platelet plug formation -- platelets stick to damaged tissue edges, release chemicals  
                    (see below), which induce more platelets to stick; also promote a wide variety 
                    of other clot enhancing phenomena, including vascular spasms and coagulation.                     
            3. Coagulation (clotting) -- a cascade of events (see book), many involve Ca+2
                    Vitamin K involved in making several clotting proteins in the liver.
        Two pathways (intrinsic and extrinsic) -- see Fig. 17.14, pg. 648. 
        Complete in 3-6 minutes.
    Clot Retraction: platelets contract (actin/myosin); pull edges of wound together
    Fibrinolysis: clot removal after tissue repair

    Chemicals to know involved in clotting/retraction/fibrinolysis: thromboplastin, 
        (pro-)thrombin, fibrin(-ogen), plasmin(-ogen), thromboxane, ADP,  prostacyclin, 
        antithrombin, heparin, histamine, tissue-plasminogen activator, PDGF, PF, TF
            Must be able to identify what cells release these and what they do.

    Hemostatic disorders:
        I. Thromboembolytic disorders: persistent clots (thrombus, embolus)
        2.. Bleeding disorders: Thrombocytopenia (red. platelet #), liver damage, hemophilia

Transfusions and Blood Groups: A/B Antigens (agglutinogens) and anti-A & anti-B 
        antibodies (agglutinins; unique because they are produced without exposure to antigens)
                Blood types; who is universal donor/acceptor, and why?
        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 intervent sulci; atriovent sulcus
        Covering: visceral (epicardium)/parietal pericardium (serous); fibrous pericardium.
        Heart Wall: epicardium/mycardium/endocardium (simple squamous)
      Chambers, valves and associated vesselsKnow right and left atria and ventricles,  
            fossa ovalis, interatrial/interventricular septa; trabeculae carneae, papillary muscles,
            chordeae tendineae; superior/inferior vena cavae, pulmonary trunk, pulmonary
            arteries and veins, aorta; atrioventricular [tricuspid and bicuspid (mitral) valves],
            pulmonary and aortic semilunar valves; pectinate muscles

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


      Cardiac circulation: right coronary artery, its branches -- marginal artery, posterior 
        interventricular artery (in posterior interventricular sulcus); left coronary artery, its 
        branches -- anterior interventricular artery (in anterior interventricular sulcus) and 
        circumflex artery. 
      Myocardial infarction

PHYSIOLOGY: Cells (described under tissues) called fibers, with intercalated disks, and  
        lots of mitochondria.  Most of heart a functional syncytium.
    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++ channels also involved (Ca++ also enters from extracellular fluids), increases
            refractory period; makes tetany virtually impossible.  Actual contraction typical of
            muscle -- Ca++ release from SR, binds to troponin . . . (as in chap 9)
         Nodal conduction system: autorhythmic cells-- use fast Ca++ channels for depolarization
            sinoatrial (SA) node (the pacemaker); atrioventricular (AV) node (delays impulse so
            atria contract before ventricles).
            Fig. 18.15, Page 675 (and handout):  Atrioventricular bundle, R & Lbundle 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

    External (ANS, hormonal) stimulation required to accelerate/decelerate heart rate (H.R.)
        Cardiac centers in medulla oblongata  -- see Fig. 18.16, page 677.
        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

    Cardiac output (C.O.): (stroke volume)  x  (heart rate)     [S.V. x  H.R.]
        Frank Starling Law
        Regulation of C.O.: autonomic nervous system controls, hormonal controls (thyroxine, 
            epinephrine), ions, physical factors (age, gender, etc.). All, of course, influence  
            blood pressure as well.*  (see below)

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

  Walls of vessels three-layered:
        1. tunica intima (interna) -- endothelium (simp. squam.); slick, continuous with 
                endocardium; 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);
                biggest in big arteries, non-existent in capillaries/small veins
        3. tunica adventitia (externa) -- loosely woven collagen with nerves/smaller vessels  
                 (vaso vasorum, branch into tunica media as well)

  Arteries: blood away from heart
        1. Elastic -- large lumen; closest to heart; withstands large pressure fluctuations, and 
                 act as auxilliary pumps; arterial pulse
   
     2. Muscular -- small to medium-sized; carry blood to specific organs
        3. Arterioles -- diameter <.5mm; smaller lose tunica adventitia; fine control of blood 
                 flow here, with precapillary sphincters

  Capillaries: 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

  Veins: Low pressure
        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 (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: 
            one way valves, large lumen (low resistance), respiratory/muscular "pumps"

     Vascular Anastomoses -- more common between veins

Physiology of Circulation: blood flow, flow velocity (rate), blood pressure, resistance -- 
            know definitions
      Resistance: greatest in small diameter vessels (most friction), especially arterioles 
                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

    *Factors affecting B.P.: cardiac output (see above), blood volume, peripheral resistance
    Regulation of B.P.: anything that influences the above factors influence B.P.
            1. neural controls: sympathetic/parasympathetic stimulation
            2. neural control units: vasomotor center (in medulla)/fibers, presso-(baro-)receptors,
                     chemoreceptors, higher brain centers (emotional, etc.)
            3. chemical controls: O2, CO2, pH, hormones (adrenal, ANF, ADH, NO)
            4. renal regulation: involves ANF, ADH, aldosterone, renin/angiotensin

For summary of effects of different factors on smooth muscle in the walls of blood vessels, see
     Fig. 19.15, page 714.

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


      Blood Flow to special areas (specific organs); at rest and during exercise
            autoregulation:   metabolic & myogenic controls; know basics of these mechanisms.

Capillary fluid dynamics: fenestrated capillaries
        involves hydrostatic pressure (on plasma) forcing fluid out and osmotic pressure (due 
        to concentrated plasma solutes [particularly albumins] left behind) pulling fluid back in.
        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 (next test!).

Circulatory Shock

(Circulatory pathways:  Pages 721 - 744.  You will find out in lab which specific vessels
    you will need to know for lab practical)