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39 Cards in this Set
- Front
- Back
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wha are the 5 main functions of muscular tissue?
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support the body (maintain posture)
produce body movements move substances within body produce heat (shivering, rapid contraction) protect internal organs & stabilize joints |
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what are the 4 characteristics of muscle?
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excitable: responds to stimuli
contractible: shortens with force extensible: can be stretched elastic: can recoil to original length |
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what are the 2 types of muscles?
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single-cell contractile units and multi-cellular contractile units
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what are the 3 single-cell contractile muscles?
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myoepithelial cells
pericytes myofibroblasts |
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what are the 3 multi-cellular contractile muscles?
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skeletal muscle
smooth muscle cardiac muscle |
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which muscle is voluntary, used for body movement and heat, has long multinucleated fibers, striated, and is controlled by motor nerves?
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skeletal muscle
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The following describes which muscle:
no striations, involuntary, small, uninucleated, mostly intrinsic contractions, slower contraction but able to hold for much longer than skeletal muscle, mostly found around tubes in your body (digestive tract, blood vessels, etc) |
smooth muscle
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cardiac muscle is also known as ___________
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myocardium
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what are the characteristics of cardiac muscle?
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involuntary, found only in the heart, 1-2 nuclei, intercalated disks, branched and striated
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what is the name of the layer that surrounds the whole skeletal muscle?
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epimysium
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which layers surrounding the skeletal muscle/fibers contain dense connective tissue?
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epimysium, perimysium, endomysium
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which layers surrounding the skeletal muscle/fibers contain loose connective tissue?
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perimysium and endomysium
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what are striations?
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ordered arrangement of contractile proteins
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what 2 things make up a sarcomere?
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myosin and actin
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arrange the following from smallest to largest:
muscle, myofibril, myofilaments, fascicle, myofiber |
myofilaments (contain actin and myosin), myofibril, myofiber, fascicle, myofiber
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what is the thick filament made up of?
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myosin
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what is myosin made up of?
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2 heavy chains, 2 light chains, head (crossbridge) has ATPase activity & tail present
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what is the thin filament made up of?
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actin, troponin, and tropomyosin (covers myosin binding site)
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what is the T system of the skeletal muscle comprised of?
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T tubules, cisternae (SR), triad
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Describe how contraction occurs in skeletal muscle
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1. ACh released, binding to receptors
2. action potential reaches T tubule 3. SR releases Ca++ 4. active-site exposure, cross-bridge binding 5. contraction begins |
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are there actin and myosin present in smooth muscle?
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yes but in irregular arrangement
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what is the shape of a smooth muscle cell?
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fusiform
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what is the length of a smooth muscle cell?
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20-500 microns
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what are smooth muscles specialized for?
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sustained contractions without fatigue
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describe the process of smooth muscle contraction
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Ca++ influx from extracellular space binds CALMODULIN -> activation of myosin light chain kinase -> phosphorylation of myosin light chains -> conformational change -> myosin/actin interaction
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which muscles are gap junctions found in?
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smooth muscles and cardiac muscles
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what are the 3 layers of the wall of the heart?
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epicardium(visceral pericardium), myocardium (cardiac myocytes), endocardium
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what kind of cells are found in the epicardium in terms of shape and layer?
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simple squamous epithelium
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what is the epicardium made up of?
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fibrocollagenous tissue with abundant elastic fibers, adipose, nerves, coronary vessels
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what is the myocardium made up of?
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collagenous connective tissue skeleton containing adipose, blood vessels, & nerves
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what type of cells make up the endocardium in terms of shape/layer?
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simple squamous epithelium
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what is the endocardium made up of?
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layer of fibroelastic tissue containing specialized cardiac fibers (purkinje fibers), blood vessels, & nerves
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what helps control blood flow in capillaries?
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precapillary sphincters
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where is the site for gas and nutrient exchange?
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capillaries (60,000mi!)
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how are nutrients and gases exchanged across the capillaries?
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diffusion across membrane (gases)
small molecule transporters transcytosis (high MW) leaks between cells |
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which type of capillary is found in most tissues, has continuous endothelium, scattered tight junctions, and transport by diffusion and pinocytosis?
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continuous capillary
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what is a fenestrated capillary?
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perforated endothelium enables extensive molecular exchange with the blood, continuous basement membrane, much great permeability, most notable in kidney glomerulus, SI, and endocrine glands
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which type of capillary has the highest permeability? why?
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discontinuous (sinusoidal) capillary because it has a perforated endothelium AND basement membrane and RBCs, WBCs, and platelets all need to be able to pass through the membrane
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where is the discontinous (sinusoidal) capillary found?
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liver, lymphoid, endocrine, hematopoietic
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