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154 Cards in this Set
- Front
- Back
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Which muscle type is multinucleated?
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Skeletal (multinucleate) and cardiac (binucleate)
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Where is the nucleus located in different muscle types?
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Skeletal - to the edge right below sarcolemma
Smooth and cardiac = central |
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What is a motor unit.
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motor neuron, its axons, and all innervated muscle fibers.
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Why do muscles die when innervated?
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There are trophic factors supplied by nerves.
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what are the names of the three layers of connective tissue coverings of muscle.
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Endomysium Perimysium, Epimysium
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Muscle tendon junctions occur where relative to muscle coverings>
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Within the epimysium. The layers fuse with collagen of the tendon
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Where are satellite cells found in muscle?
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In skeletal muscle they are found outside the sarcolemma but within the basement membrane.
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What do satellite cells do?
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repair or build muscle fibers.
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Describe Red fibers (Type I) in skeletal muscle.
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Smaller than White
Resistant to Fatigue lots of myoglobin lots of mitochondria slow twitch Less tension than white Strong NADH and succinate dehyudrogenase activity (histochemical) |
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Histochemical analysis of skeletal muscle depends on what?
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NADH and succinate dehydrogenase reaction products.
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Describe White Fibers (Type IIb)
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larger diameter than red.
fast twitch glycolysis based fatigue easily LArge peak force of contraction. |
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What are Type IIA Fibers.
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- Intermediate fibers with characteristics of white (type II) and red (type I ) fibers
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breakdown a muscle into its components.
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Muscle fascicle Muscle fiber - myofibril - sarcomere
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Thick filaments are what?
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Myosin
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Thin Filaments are what?
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actin
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Z line
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boundaries of sarcomere - anchor thin filaments
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A band
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the length of thick filaments including overlapping thin filaments.
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I band
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only thin filaments
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H band
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Only thick filaments
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M line
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center of the sarcomere... holds the thick filaments.
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During contraction, which bands shorten?
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I and H bands
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what moves in muscle contraction.
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Interaction with myosin head moves actin filaments over myosin filaments.
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Troponin has what 3 subunits.
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TnT - binds tropomyosin
TnC - binds calcium TnI - inhibits. |
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Where do t-tubules exist?
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In between terminal cisternae at the AI junction (triads) in skeletal muscle.
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Muscle Spindle
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Stretch receptor. - contains intrafusal fibers.
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Intrafusal fibers are subdivided into two categories.
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Nuclear bag and nuclear chain
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Differentiate Nuclear Bag Fibers and Nuclear Chain Fibers.
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Bag fibers on only sesory and are found centrally.
Chain fibers - are toward the ends... linearly arranged. |
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Golgi tendon organ
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sensory organ which responds to tension in skeletal muscle... purely sensory (Affarent)
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Intercalated disks
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found only in cardiac tissue... separates cardiac muscle cells - contains adhesive junctions, gap junctions, and desmosomes.
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Differentiate Skeletal and Cardiac Muscle?
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Cardiac muscle has some branching, there are Diads formed at the Z line instead of triads at the AI junction. Junctions are intercalated dsks. Cardiac muscles are stimulated by pacemaker and purkinje cells rather than nerves (autonomic rather than somatic control) Centrally placed nuclei. NO satellite cells.
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Desmin and vimentin are found where?
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dense bodies in smooth muscle.
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Dense bodies.
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Substitute for the organized myofilaments of skeletal or cardiac muscle.
This are areas where contractile elements criss cross. they contain alpha actinin and bind with vimentin and desmin. |
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What are caveoli
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similar to t-tubules... these are pinocytic invaginations.
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Does smooth muscle atrophy or develop with aging?
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Develops. Vascualr structures see growth of smooth muscle
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Is tromomyosin in the thick or thin filament?
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The thin filament [ Actin, troponin, tropomyosin]
The thick filament is only myosin |
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Troponin C has what bound to it when calcium is not present?
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Magnesium
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Why is aTP required for skeletal muscle function.
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1.) causes contraction
2.) Sequesters calcium - relaxation |
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Recruitment
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continulous sensory feedback enabling you to use the appropriate motor units for a function.
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Golgi tendon vs Muscle spindle: what do they detect?
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Golgi tendon = tension
Spindle = stretch. |
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What protein is not produced in muscular dystrophy? What is this protein's function?
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distrophin - maintains structure of plasma membrane.
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Botulinum toxin does what?
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blocks Ach Release = relxation = botox
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Curare does what?
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inhibits ACh receptors
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Succinyl Choline
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inds to Ach receptors and keeps channels open
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Physostigmine
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inhibits Acetylcholine esterase.
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Which has more finite control? Skeletal or smooth?
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Skeletal muscle
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Smooth muscle... is it controlled by calcium? does it have troponin?
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Yes it is controlled by calcium... but it does not have troponin.
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Myosin Light Chain kinase... explain.
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It is located in smooth muscle, activated by calmodulin when calcium binds.
MLCK phosphorylates and activates smooth muscle myosin. |
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Epinephrine causes smooth muscle relaxation how!
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Activates andenylate cyclase whch leads to phosphorylation of myosin light chain kinase and deactivates it.
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What is unique about ventricular action potentials?
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The presence of a plateu phase during repolarization. (controls contraction rate of the heart.)
Caused by calcium influx |
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Myoepithelial cells
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aid in secretion by contraction near acinal protions of glands or ducts. contain desmin
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where are myoepithelial cells located.
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within the basement membrane (they are part of the epithelium
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Myofibroblast.
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Looks like a fibroblast with rER. you find actin and myosin filaments. (varient of smooth muscle cells.
Secondary would healing and tooth eruption. - bring tissues together after injury. |
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What are the general features of the tunica intima?
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Endothelium, basal lamina, subendothelial space
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What are the general features of the tunica media
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Muscular layer, smooth muscle, elastic lemellae, reticular fibers, ground sunstance.
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What are the general features of the tunica adventia?
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Type 1 collagen, macrophages, vasovasorum, nervi vascularis.
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What produces the elastin in the tunica media of eleastic arteries?
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Smooth muscle (NOT FIBROBLASTS)
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Elastic Arteries have what distinct feature in the tunica intima.
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an elastic band called the internal elastic lamina
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stenosis
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narrowing of the lumen of a vessel
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Cardiac Tamponade
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When the pericardial cavity fills with blood and hinders beating.
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Key features of muscular arteries.
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Thinner tunica intima (still has internal elastic lamena) No external elastic lamina though.
Thinner tunica media Tunica media may have vaso vasorum and nervi vascularis. |
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Arteries
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thinner tunica intima
Thinner tunica media (1-2 layers of smooth muscle) |
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What are pericytes?
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stem cells for the vasculature.
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What is the diameter of a capillary?
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7.5 um
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Whwere are fenestrated capillaries?
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Gastrointestinal system + endocrine system
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how large are fenestrations?
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80nm
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Where are discontinuous capillaries?
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spleen live bone marrow - allows transport of RBCs
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Which of the 3 classes is the largest capillary?
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Discontinulous 20um ish...
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The vena cava has what distinct feature.
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Very thick adventitia
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Why do we not see atherosclerosis in veins?
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You need oxidized LDL - veins carry deoxygenated blood.
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What should you not use intravenous lines for?
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concentrated solutions.
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What is a central line?
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a catheter in the right side of the heart... you can put in concentrated solutions.
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How much of CO goes to the kidney?
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25%
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Flow equation
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Pressure difference / resistance
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What is the major determinant of resistance in blood flow?
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radius
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if you double the radius, how much will it increase flow
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16 times!
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How do you control arterial pressure? (what part)
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arterioles.
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Why do the veins have valves.
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Keeps directionality- muscle movement allows movement of blood through veins.
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Continuous capillaries... where?
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lungs and brain!
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Fenestrated capillaries where?
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kidneys, liver, digestive tract, endocrine
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COX inhibitors lead to low or high blood pressure? Why?
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High - it blocks prostacyclin dilation.
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Endothelin and ACE lead to high or low blood pressure?
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High - vasocontriction.
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sheer stress causes dilation or constriction.
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usually dilation... until it is chronic or severe... then it is constriction.
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67% of your blood is where?
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In your veins.
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what leads to venous tone increase?
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Epinephrine -> adrenal medulla
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Pituitary glands and blood flow
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pituitary gland produces vasopressin which leads to vaso constriction.
It is triggered by baroreceptors in the heart and arteries. |
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What is the critical parameter of blood flow.
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mean arterial pressure
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what is the easiest way to determine if it is an artery or a vein?
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Veins are more distorted
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What is unique about smooth muscle in the tunica media of the Aorta?
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It produces the elastic material of the ECM... typically this is the job of a fibroblast.
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how can you tell the tunica media from the tunica adventitia in large veins.
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nuclei of small veins are oriented differently.
Media = longitudinal Adventia = circular |
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Do you see vaso vasorum in Large veins?
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YES! in the tunica adventitia
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What is the difference between elastic and muscular arteries?
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Muscular arteries have no external elastic lamina
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how can you differentiate peripheral nerve from smooth muscle?
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peripheral nerve fasicles are naturally wavy.
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What is severed in a vasectomy?
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the vas deferens
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Pampiniform Plexus
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Veins strategically placed around testicular artery. - acts as countercurrent heat exchanger.
arterial blood is cooled by the veins |
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PostCapillary-Venules look like what?
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muchwider than an RBC but still only an endothelial tube
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Sinusoidal capillaries
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Discontinulous capillaries common in the liver.
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The liver has what type of capillaries.
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Discontinuous (sinusoid)
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What are the layers of epidermis from inside to outside?
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Basal (germinativum), Spinosum, Granulosum, Lucidum, corneum
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What is produced in the stratum Basale which is a precursor to keratin?
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tonofilaments
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Stratum Spinosum converts Tonofilaments to what? What function does the stratum spinosum confer?
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Tonofibrils
Prevents skin abrasions. |
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What is visually unique about the stratum spinosum?
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presence of desmosomes that look like spines.
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Lamellr bodies
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lipid pockets which confer waterproof nature to skin. Found in stratum granulosum.
Nuclei begin to breakdown in keratinization process. |
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Stratum Lucidum
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Only part of thick skin. Pale to eosinophilic, not easily seen
may be part of stratum corneum |
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Stratum corneum
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mostly keratin.
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Rete Ridges
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Epidermal extensions into the dermis
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Dermal papillae
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dermal extensions moving up to the epidermis.
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What are the two layers of the dermis?
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Papillary Layer - meissners corpuscle (not meisners plexus) - tornadic touch receptors.
reticular |
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what is found in the hypodermis?
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PAcinian corpuscles (vibration sensors)
unilocular fat, sweat glands, hair, sweat gland ducts |
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pacinian corpuscles sense what? where are they found?
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vibration - hypodermis and pancreas
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Sebaceous cysts
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formed when an outlet of a seaceous gland is obstructed... very firm.
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how do you perform reepithelization. (3 cell sources)
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Periphery cells
Hair follicle cells migrations Sweat gland cells migration. |
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Small intestine layers
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Mucose
submucosa Muscularis externa Adventitia |
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what cells line villi?
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enterocytes: simple columnar
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what makes up the mucosa of the small intestine?
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Mucosa: muscularis mucosa, lamina propria, basal lamina, epithelium
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Goblet cells increase as you travel distally or proximally to the stomach?
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Distally
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what do goblet cells secrete - what mechanism.
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mucinogens - mericrine.
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Crypts of lieberkuhn
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Undifferentiated cells which igrte with time.
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Panneth cells.
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secrete lysozyme (antibacterial)
Red found in base of crypt of lieberkuhn |
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Ulcers occur when damage breaks through what layer of the intestine?
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Lamina Propria of the mucosa.
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Muscularis externa is composed of what?
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Inner circular smooth muscle - contraction shrinks lumen diameter
Outter longitudinal layer - contraction shortens the intestinal tract. |
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Serosa
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smooth endothelial layer which prevents volvulus. - lowers friction.
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absence of bowel sounds indicates what?
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ileus (shutting down the gut)
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during ileus what is your hosptial feeding pattern?
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NPO - nothing by mouth.
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Brunner's glands.
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Duodenum glands which secrete alkaline mucus to neutralize the acidic chyme.
Located in the sumucosa |
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What is found in the jejunum?
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moderate goblet cells and panneth cells.
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Peyer's patch
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found in ileum - has M cells with microvilli called microplicae.
it is antigen presenting cells. |
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What kind of epithelium faces the outside world?
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Keratinized stratified squamous epithelium
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Why is this type of epithelium found here?
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Protection
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Which layer of the epidermis is especially rich in desmosomes?
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Stratum Spinosum
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Which layer of the epidermis is especially rich in hemidesmosomes?
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Stratum Basale?
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What separates the dermis from the epidermis?
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Basal Lamina
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How many layers are there in the dermis?
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Two - pappillary (top) Reticular (below
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The dermis is comprised of what?
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vessels. type 1 collagen (reticular layer), dense ireegular connective, ground substance, some eleastic andreticular fibers
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Which is the most basophilic layer of the epidermis?
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Stratum granulosum
Coratohyaline granules Keratinization starts here. |
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Pruning is caused by what?
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glycolipid removal from stratum granulosum
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Meissner's corpuscles look like what?
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Tornadoes - touch!
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Pacinian corpuscle
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Huge circular strutcture with a unmyelinated axon at the center and spiralling nuclei of fibroblasts
vibration sensor Looks like an onion cut. |
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Coarse fibers of collagen indicate that you are looking at what layer of the dermis?
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reticular layer
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what part of the hair follicle is acted upon by sebaceous glands?
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upper 1/3rd
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pyknotic nuclei
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condensed down (as is seen in sebaceous gland secretions)
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What is the terminal web.
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holds microvilli in simple columnar epithelium of small intestine.
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What do brunners glands look like?
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tall simple columnar. - only in duodenum
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Ulcers have reached what layer f the small intestine?
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Submucosa
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Goblet cells are found where in the small intestine.
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Few Duodenum
Some Jejunum Most Ileum |
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Panneth cells are found where in the small intestine.
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Duodenum... some jejunum
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How do we differentiate between Jejunum and Duodenum.
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Jejunum will have panneth cells but no brunner's glands.
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The nuclei in lymphatic vessels are a dead giveaway... why?
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They are all white blood cells!
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Meissner's plexus
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neurons which facilitate epithelial function in the small intestine.
NOT meisners corpuscles |
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Circular muscle has what appearance in their nuclei
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long not very round.
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longitudinal smooth muscle has what appearance of nuclei?
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more round.
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Auerbach's plexus
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foudn in between inner circular and outter longitudinal muscle... they initiate peristalsis in the small intestine.
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Peyer's patches
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confluent lymphatic nodules. with flattened villi. Found in the ileum
Contain M cells with microplicai (small microvilli) |
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M cells are found where?Where?
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in peyers patches - in the ileum of the small intestine.
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between the muscularis externa smooth mucle components you find what?
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aeurbach's plexus - important for peristalsis.
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