Micro Review 6: Even more Blood cell review and Vasculature

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Micro Review 6 Even more Blood cell review and
Vasculature

• Boggusrl_at_email.uc.edu

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Lymphocytes

• Agranulocyte
• 6-18 um, 20-30 in circ. blood
• Small, with thin rim of cytoplasm around dense
  round nucleus
• Size of nucleus same size as RBC
• 3 classes
• B cells (bone marrow derived, activated into
  plasma cells to produce antibodies humoral
  response)
• T cells (from thymus, helpers, suppressors,
  cytotoxics, recognize foreign antigens cell
  mediated immunity)
• NK cells

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Monocytes

• 12-20 um, 3-8 in circ. blood
• Largest white cell in peripheral blood smear
• Nucleus round to horseshoe-shaped
• Chromatin less condensed and more delicate than
  lymphocytes
• Azurophilic granules but still called an
  agranulocyte
• 1.5 days in circ.
• Differentiate into macrophages in tissues
  (mitotic division)
• Phagocytosis and APC

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Eosinophils

• 2-4 of leukocytes in circulating blood
• 12-15 um
• 3-4 hours in bloodstream
• 8-12 day life span
• Easiest to recognize on EM on because of large
  oval specific granules that each contain
  elongated crystalloid
• About 200 specific granules per cell
• Crystalloid center has large amounts of major
  basic protein that accounts for eosinophilia
• Granules also contain peroxidase, eosinophilic
  peroxidase, acid phos, and ribonuclease

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Neutrophils

• 60-70 of leukocytes in circulating blood
• 12-15 um
• In circulation 6-7 hours, life span few days
• Highly lobulated nucleus
• Kill bacteria (know how that works with proton
  pumps, granule dumping, and superoxide anions)
• Azurophilic granules primary lysosomes
• Myeloperoxidases, acid phos
• Specific granules most abundant
• Contain alk phos, collagenase, lactoferrin,
  lysozyme

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Eosinophils

• Large increase seen in parasitic infections and
  allergic states
• Ingest antigen-antibody complexes
• Counteract with histamine secreted by basophils
  and mast cells
• Lots of them in mucosa lining opennings to
  exterior

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Basophils

• 12-15 um, 0-1 of circ. blood
• Segmented nucleus, irregular of lobes
• Biggest granules ever (in size)!
• Water soluble, containing peroxidase, histamine,
  and heparin NO lysosomal enzymes!
• Have IgE receptors to dump granules when it comes
  in contact with an allergen

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Reticulocytes

• Larger than mature erythrocyte
• Nucleus is extruded
• Cytoplasm is faintly basophilic
• Why? RNA

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Plasma cells

• Differentiated B cells that secrete antibodies
• Beer belly displaced nucleus (isnt it cute?)
• Humoral immunity

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Megakaryocytes

• Where platelets come from
• Found next to sinuses in hematopoietic
  compartment
• Progenitor is megakaryoblast, that exhibits
  endomitosis (usually go to 16n polyploidy), one
  large lobulated nucleus
• Non-platelet forming megakaryocyte (less
  cytoplasm and basophilia, more azurophilic
  granules)
• Platelet forming has proplatelets projecting into
  marrow sinuses
• Each forms 4000-8000 platelets

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Basophilic erythroblast

• Intense basophilia extremely purple
• No nucleoli
• Clumped chromatin with spoked wheel appearance
  know these stupid ways they tell you to
  remember certain cells because they can use this
  on the written
• Spoked wheel
• Lacy appearance
• Checkerboard
• know what these go with

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Myelocyte red is eosinphilic and green is
neutrophilic

• Mitotic cells
• Has specific azurophilic granules
• No nucleoli
• Nucleus round to oval
• More condensed chromatin

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Band form / Stab cell neutrophilic circled here

• Postmitotic
• Full complement of specific granules
• Horseshoe-shaped or U-shaped nucleus

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Metamyelocyte - eosinophilic is green circle

• Postmitotic
• Almost full complement of specific granules
• Kidney-shaped nucleus

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Orthochromatophilic erythroblast red circle

• Dense heterochromatin in large clumps with no
  intervening euchromatin
• Cytoplasm nearly as eosinophilic as mature
  erythrocyte (but still faintly basophilic)

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Myeloblast

• Basophilic cytoplasm
• NO granules
• Light staining nucleus
• 5 or more nucleoli

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Promyelocyte green circle

• Azure granules
• Some condensing of chromatin
• 1-3 nucleoli
• Really big
• Ps. Red circle is eosinophilic myelocyte

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Polychromatophilic erythroblast blue circle

• Coarse condensed chromatin
• Greyish cytoplasm
• Marks beginning of heme synthesis
• Mitotic cell
• Ps. Red circle is neutrophilic band/stab cell

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Promyelocyte

• Azure granules
• 1-3 nucleoli
• Really big
• Look purplish

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Promyelocyteremember the azurophilic
gtranules!!!!!Still has a few nucleoli
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Vascular Systems

• What are the two vascular systems in the human
  body and their components?

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Vascular Systems

• What are the two vascular systems in the human
  body and their components?
• Blood vascular system
• Composed of all blood vessels (arteries
  capillaries and veins) and the heart
• Lymphatic system
• Consists of vessels that retrieve lymph
• What is lymph?
• Tissue fluid derived from plasma plus WBCs

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Organization of Vessels

• What are the three layers of a blood vessel?

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Organization of Vessels

• What are the three layers of a blood vessel?
• Tunica intimainnermost layer
• Tunica mediamiddle layer
• Tunica Adventitiaoutermost layer

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Tunica Intima

• What does it include?

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Tunica Intima

• What does it include?
• Layer of simple squamous epithelium (endothelial
  cells) lining lumen of the tube
• Endothelial cells form basal lamina
• Subendothelial layerloose CT and in some cases
  scattered sm. muscle

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Tunica Media

• What is it composed of?

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Tunica Media

• What is it composed of?
• Circularly arranged smooth muscle cells and CT
  (elastic fibers!)

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Tunica Adventitia

• What is it composed of?

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Tunica Adventitia

• What is it composed of?
• Outermost layer composed of collagenous CT with
  some elastic fibers
• May be indistinguishable from surrounding CT

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• What can separate the tunica intima from the
  tunica media?
• Where is this separation likely to happen?
• What about the tunica media from the tunica
  adventitia?

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• What can separate the tunica intima from the
  tunica media?
• Internal elastic lamina
• Where is this separation likely to happen?
• In arteries, large arterioles, and sometimes
  large veins
• What about the tunica media from the tunica
  adventitia?
• External elastic lamina

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• What is the vasa vasorum?

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• What is the vasa vasorum?
• Branches that supply the outer layers of a
  vessel can be branches from the same vessel (if
  its an artery) or from a nearby artery

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Large Conducting/Elastic Artery

• Thick Tunica Intima
• Tunica media is smooth muscle alternating with
  elastin sheets (helps control blood pressure)
• Tunica adventitiathin, collagenous
• Cannot distinguish internal and external elastic
  laminae from other elastin in section think
  LOTS OF ELASTIC FIBERS HERE!!!!!!!

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Medium/Muscular/Distributing Arteries

• Tunica intimascattered sm. Muscle cells in
  subendothelial layer
• Tunica media is thickestcircularly arranged sm.
  musc, some elastic lamina
• Assists in distribution of blood to organs
• Tunica adventitiacollagenous, often not
  distinguishable from surrounding CT
• Can see internal elastic lamina.

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Small artery and arterioles

• Tunica intimasingle layer of endothelial cells
• Tunica media1-2 layers spirally arranged sm.
  Muscle (arterioles) up to 6 layers for sm.
  arteries.
• Are used to control vasoconstriction and dilation
• Tunica Adventitiathin and collagenous
• Internal elastic lamina present in large vessels
• Endothelial cells of arterioles contain
  Weibel-Palade granules

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Capillaries

• Involved in exchange of material between blood
  and surrounding tissue
• Basically endothelial cells and basal lamina
• Pericytespartially surround endothelial cells
  and have their own basal lamina (fuses with
  endothelial cell lamina)
• Sinusoidshave wider diameter

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Capillaries and Sinusoids

• Continuous Capillaries/sinusoids endothelial
  cells joined by tight junctions and a continuous
  basal lamina
• Have pinocytic vesicles suggesting transcytosis
  as transport mechanism because tight junctions
  dont allow stuff to cross
• Fenestrated Capillaries/sinusoidsendothelial
  cells have pores (fenestrations) through the
  cytoplasm
• Thin diaphragm transverses these pores
• Basal lamina is continuous even across
  fenestrations
• Discontinuous Capillaries/sinusoidsincomplete
  endothelial lining and basal lamina

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Capillary Bed

• Describe the following
• Thoroughfare
• Precapillary sphincters
• Areteriovenous shunts

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Capillary Bed

• Describe the following
• Thoroughfare main path through capillary bed,
  flow through it is continuous whereas it can be
  intermittent to branches
• Precapillary sphincters rings of sm. Muscle that
  control flow from metarterioles into capillaries
  (respond to things like lactic acid conc, and O2
  conc.
• Arteriovenous shunts allow blood to bypass
  capillary bedsregulated by ANS

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Veins

• Carry blood towards the heart
• Wall thickness is apprx. 1/5 size of lumen
• Leads to more irregular profile
• Blood pressure is lower in veins

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Venules - here blue is venule and red is
arteriole COMPARE LUMEN and WALLS

• Tunica intimaendothelial cells
• Tunica mediafew pericytes? 1-2 layers of sm.
  Muscle in larger venules
• Tunica adventitia thick and continuous with
  surrounding CT

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Medium veins

• Tunica intimathin, endothelial cells, maybe some
  CT
• Tunica mediamore sm. Muscle than venules but
  less than medium arteries
• Tunica adventitiathick with some elastic fibers
• Some have valvesextensions of tunica intima

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Large Veins

• Tunica intimawell developed (that means
  prominent)
• Tunica mediaunderdeveloped
• Tunica adventiathick/well developed, can contain
  longitudinally arranged sm muscle this is KEY

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Heart

• Endocardiumanalagous to tunica intima
• Simple endothelial layer with subendothelial
  later of CT
• Subendocardial layeradjacent to myocardium
• Contains veins, nerves, sm muscle, and purkinje
  cells
• Endocardium is THICK in ATRIA, thin in ventricles
• Myocardiumtunica mediathickest layer of heart,
  esp in ventricles
• Epicardiumtunica adventitiaelastic and adipose
  tissue

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KNOW THIS!

• You will be expected to say where on the heart a
  specimen is from!!!! You cannot just say heart
  tissue You will need to know atrium vs.
  ventricle

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Valves

• Elaborations of the endocardium
• Core of collagen and elastic fibers?lamina
  fibrosa, covered by endothelium
• At base of the valves, lamina fibrosa froms
  annulus fibrosus
• Separates myocardial cells of atria and ventricle
  physically and electrically
• Chordae tendineae anchors free edges of valves
  to ventricle wall
• Papillary musclespresent where chordae tendinae
  insert

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Atrium
Ventricle
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Circleannulus fibrosis
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Lymphatic system

• Structure similar to veins but usually thinner
  walls
• Held open by anchoring filaments
• Have numerous valves to prevent back-flow

Valveprevents back flow
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Portal Systems

• Variations from normal flow of heart?arteries?capi
  llaries? veins?heart
• They are veins/venules or arteries/arterioles
  that connect two capillary beds before returning
  to the heart
• Hepatic portal systempicks up nutrients absorbed
  in digestive tract and delivers them to liver for
  processing and all the fun crap that SER does
  like de-tox.

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Tumors and angiogenesis

• Tumors--- angiosarcomas (endothelial cells) or
  hemangiopericytomas (from pericytes)
• Angiogenesisformation of new blood vessels
• Angiogenic factors play a role

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Atherosclerosis and arteriosclerosis

• Arteriosclerosishardening of arteries due to
  death of sm. Muscle cells in tunica
  media?replaced by scar tissue and calcium
  deposits
• Atherosclerosis focal thickenings of tunica
  intima
• Steps involved?

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Atherosclerosis and arteriosclerosis

• Arteriosclerosishardening of arteries due to
  death of sm. Muscle cells in tunica
  media?replaced by scar tissue and calcium
  deposits
• Atherosclerosis focal thickenings of tunica
  intima
• Steps involved?
• Injury to endothelium
• Monocytes attach to damaged surface
• Monocytes migrate subendothelially become
  macrophages
• Macrophages accumulate lipid? foam cells
• Platelets adhere to endothelial surface
• Platelets and endo cells produce PDGF
• Chemoattractant and mitogen for sm. Muscle
• Smooth muscle migrates from tunica media into
  intima and proliferates also accumulate
  lipid?more foam cells
• Sm. Muscle cells produce ECM?plaques

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Aneurysm

• Thinning of the wall of a blood vessel allows
  formation of an aneurysm
• Ballon like extention of a vessel that may
  rupture
• Dissecting aneurysmpools of blood accumulate
  between tunics

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Some general hints for blood vessel ID

• First decide if its artery, vein, or lymph
• Look at thickness of tunica media and for the
  presence of elastic fibers
• Look for valves
• Look for shape integrity
• Also look for RBCs in the lumen, if you THINK
  its a lymph vessel but its full of RBCs then you
  are wrong.
• Then look for relative sizelook at other vessels
  in section, count muscle layers, make an educated
  decision

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Identify
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Hints Look at size of lumen compared to wall
thickness Then look at the tunica media How many
layers of muscle?
Arteriole because it has less than 6 layers of
muscle in tunica media
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Identify
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• Hints picture it if the outer layer were a blue
  green color
• Look at the relative size of the luminal later
  compared to the middle layer
• ATRIUM OF THE HEART

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Identify
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• Hints Look at wall thickness
• What is in the lumen (purple cells)
• LYMPHATIC VESSEL

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Identify
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• Same hints applylook at size of tunica media and
  for the presence of elastic
• Large Conducting/Elastic Artery

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Identify
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• Hints look at color of cytoplasm
• Look at shape of nucleus
• Neutrophilic band/stab cell

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Identify
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• Hints size!
• Number of layers
• Capillary
• Notice that the RBC in the lumen takes up almost
  the entire lumen

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Identify
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• Hints lumen? wall ratio
• Thickness of sm muscle layer
• Internal elastic lamina
• Muscular artery

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Identify
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• Green arrow endothelial Cell
• Red Arrow pericyte
• Note the shared basal lamina

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Identify
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• Hints
• -- granules
• -- nucleoli
• Promyeloctye

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Identify
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• Hints
• The orientation of the muscle remember the dead
  giveaway is the longitudinal smooth muscle in the
  adventitia
• The thickness of the various layers
• Large Vein

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Identify
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• Hints Layers?
• Size?
• Venule
• The other thing is an arteriole so you can see
  they are almost the same size appreciate the
  thicker walls and smaller lumen of the arteriole

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Identify
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• Hints
• What is the tissue?
• Look at the thickness of the layers?
• Ventricle

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Identify
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• platelet
• Small size compared to RBCpurple color

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Muscular artery

• Tunica media thickest
• Highlighted internal elastic lamina
• Can see external elastic lamina in big ones

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Medium veins

• Tunica intima thin with endothelial cells and
  scant subendothelial connective tissue
• Less smooth muscle than arteries in tunica media
• Tunica adventia thick with some elastic fibers
• Have valves
• Extension of tunica intima

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Internal Elastic Lamina

• Found here in.. MUSCULAR ARTERY

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Elastic artery

• Tunica intima thick
• Tunica media has many layers of smooth muscle
  cells alternating with parallel fenestrated
  sheets of elastin
• Tunica adventia thin
• Internal and external elastic lamina may be
  present

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Large veins

• Tunica intima well developed
• Tunica media undeveloped
• Tunica adventia thick and well developed with
  longitudinally arranged smooth muscle (definitely
  the easiest way to remember what this looks like)

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Arterioles red arrow

• Tunica intima is single layer of endothelial
  cells
• Tunica media is one or two layers of spiral
  smooth muscle (not four layers of smooth muscle,
  which would be a small artery)
• Tunica adventia thin and collagenous
• Internal elastic lamina may be present in largest
  ones

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Venules blue arrow

• Tunica intima is endothelial cells
• Tunica media is few pericytes to 1-2 layers of
  smooth muscle
• Tunica adventia thick, continuous with
  surrounding CT

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Lymphatics

• Numerous valves prevent backflow
• Will have WBCs in the lumen

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More lymphatics

• Although you dont see WBC notice how thin the
  walls are and how there are VALVES

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Heart

• Annulus fibrosis (green circle) is where
  ventricle, atrium, and valve all meet
• Epicardium (green layer, blue arrow) the tunica
  adventitia of the heart
• Myocardium (red arrow)
• Ventricle has thicker myocardium
• Atrium has thinner myocardium and thicker
  epicardium

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heart

• Ventricle opening into large artery, with heart
  valve
• Right ventricle, valve (do remember which one
  from Gross lab?), pulmonary artery
• OR Left ventricle, valve, aorta

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Purkinje fibers

• Impulse conducting system of the heart
• Recognized because they are larger than their
  neighboring contractile fibers and their
  myofilaments are located in the periphery of the
  cell. (Look at an EM of this)
• Lots of perinuclear glycogen gives center a pale
  appearance

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Capillary

• Can fit exactly one RBC in lumen

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Another capillary

• Because only ONE endothelial cell surrounds the
  lumen

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CONTINUOUS capillary

• Pinocytic vesicles are KEY
• The wall is continuous this makes sense

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FENESTRATED capillary

• Notice the basal lamina still continues over the
  fenestrations
• I guarantee they will give you EMs of capillaries
  (contin, fenes, discontin) so I highly suggest
  taking a peek at these in the EM book that you
  can check out in the comp lab

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PEACE OUT

• If you have questions do not hesitate
  boggusrl_at_email.uc.edu