Term
| What is responsible for cells changing shape? |
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Definition
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Term
The 3 Muscle Types Voluntary - Nuclei Number - Nuclei Location - Intercalated Discs - Cross Striated |
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Definition
Nuclei Nuclei Cross- Interca Voluntary Number Location Striaed Disc SK Yes Multiple Peripheral Yes No
C No 1-2 Central Yes Yes
SM No One Central No No
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Term
| Smooth Muscle Myofilament Arrangment |
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Definition
| Less orderly b/c not striated |
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Term
Involuntary Smooth and Cardiac Contraction (Nerve Role) |
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Definition
-sympathetic and parasympathetic autonomic (visceral) efferent nerves have postganglionic unmyelinated axons that terminate in these muscle cells -nerves modify the intrinsic contractions DO NOT initiate them
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Term
| Epi-, Peri-, and Endo- mysium |
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Definition
Epi = surrounds entire named muscles Peri = surrounds bundles (fascicles) Endo = surrounds individual mucle cells |
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Definition
-dark staining -birefringent/birefractive in polarized light -refract twice -split light ray into 2 |
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Definition
DO NOT alter polarized light |
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Definition
-occupy most of cytoplasm -banding does not occupy cytoplasm between myofibrils |
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Term
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Definition
-composed of a bundle of myosin molecules -"two-headed" dnetal mirror -head and shaft region |
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Term
| Head of Thick Myofilament |
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Definition
- have ATP binding sites and ATPase which splits ATP - can bind to actin on thin filaments (actin-binding sites) -pair of light chains |
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Term
| Shaft of Thick Myofilament |
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Definition
-shaft = 2 heavy elongated chains twisted around each other Heavy Chain has 2 regions Light Meromyosin = most of shaft Heavy Meromyosin = head and adjacent part of shaft
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Term
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Definition
-Major structural component = filamentous actin(F-actin) which is a polymer of globular (G-actin) monomers -2 F-actin twist around each other forming double helix -have binding sites for myosin heads |
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Term
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Definition
-filamentous structure (thinner than F-actin) -double chain of plypeptides -lies in grooves on F-actin surface -rest: covers myosin-binding sites on G-subunits |
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Term
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Definition
-at intervals attached tropomyosin -complex of 3 globular subunits -binds to Ca+ ion |
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Term
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Definition
Attachment (myosin head to actin) Bending (of myosin head pulling thin over thick filam) Detachment (of myosin head) Straightening (of myosin head) |
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Term
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Definition
| Depends on stimulation of muscle by impulse conveyed by nerve axon |
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Term
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Definition
-system of tubules and cisternae -form shealth around each myofibril -form 2 "terminal cisternae" at A-I region -part of triad
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Term
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Definition
-part of triad -transverse with respect to long axis of myofibrils -narrower than termial cisternea -are the invaginations of the sarcolemma at A-I boundaries at right angles -invaginations undergo branching -Blind end of T tubule is between the 2 terminal cisternea -in direct contact with Ca+ channels in terminal cisternea -during depol; change shape |
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Term
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Definition
-where axons communictae with skeletal muscle -where motor axons terminate -axon splits into branches here; the branches have acetylcholine |
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Definition
| occupies narrow cleft between axolemma and sarcolema (sarcolemma is heavily folded) |
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Term
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Definition
Impulse reaches end of axon --> depol opens Ca channels --> Calcium into nerve --> release of acetylcholine vessicles --> binds to receptors on sarcollema -->opens Na and K channels --> depol of muscle --> AP
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Term
| Type I Skeletal Muscle Fibers |
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Definition
-smaller -red (myoglobin) -many mitochondria -continuous, slow contraction -resistant to fatigue |
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Term
| Type II Skeletal Muscle Fibers |
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Definition
-larger -paler (less myoglobin) -fewer mitochondria -rapid, discontinuous contractions -fatigue rapidly |
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Term
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Definition
-Have both motor (efferent) and sensoy (afferent) nerve endings -convey info to CNS |
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Term
| Neurotendonous Organs (Golgi Tendon organs) |
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Definition
-at junctions of skeletal muscles and their tendons -sensory nerve endings terminate b/w bundles of collogen -no motor nerve fibers -stretching tendon stimulates sensory nerve endings which transmit impulses to the CNS |
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Term
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Definition
-cross striated -cross banding less evident -cells often branch near ends |
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Term
| Cardiac Muscle Ultrastructure |
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Definition
-mitochondria arranged in rows (more numberous) -SR less developed -SR surrounds groups of myofibrils -T tubles larger and occur in Z line -Diads not triads -T tubules associated with 1 lateral expansion of SR (not 2 terminal cisternea) |
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Term
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Definition
-junctions between ends of cells -coincide with z-lines -zig-zag of ends of cells |
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Term
| Intercalated Disc Junctions |
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Definition
Transverse Desmosomes- bind adjacent cells and transmit tension along fibers Zonule Adherens- anchorinf sites for actin myofilaments Longitudinal Gap Junctions- permit impulses to pass from cell to cell |
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Term
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Definition
-smaller -contain fewer T tubules -contain more membrane-limited granules precurser of atrial natriuretic factor -acts on kidney by opposing ADH and aldosterone leading to H2O and Na loss
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Term
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Definition
-in subendocardium -involved in impulse conduction -larger than ordianry cardiac cell -cytoplasm occupied by glycogen |
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Term
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Definition
Both sypathetic and parasympathetic terminate in nodes
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Definition
-slow contraction without fatigue -innervated by both sypathetic and parasympathetic |
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Term
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Definition
In connective tissue in prostate gland
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Term
| Smooth Muscle - Small Bundles |
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Definition
In -arrector pili muscles of skin -iris of eye -larger arteries Richly innervated (each cell gets its own nerve axon) Very precise graded contractions |
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Term
| Smooth Muscle - Unitary or Visceral |
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Definition
-Occurs in sheets -Poor nerve supply one axon for group -Cells receiving impulse transmits it to adjacent cells via gap junctions (abundent)
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Term
| Smooth Muscle - Ultrastructure |
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Definition
-have RER and Golgi b/c secrete collegen, elastin, and ground subst. -each cell enclosed by basal lamina and reticular fibers -no T tubules |
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Term
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Definition
Gap junctions between adjacent cells in smooth muscle
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Term
How smooth muscle delivers Ca+ to cytoplasm (3 was) |
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Definition
1. rudimentary SR 2. many cytoplasmic vesicles near SR 3. small invaginations of cell surface (caveolae) |
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Term
| Smooth Muscle - Cytoskeleton |
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Definition
Consists of: Intermediate Filaments Desmin = non-vascular smooth muscle Desmin + Vimentin = vascular smooth muscle Dense Bodies (alpha-actinin) = in cytoplasm Attachment Plaques (alpga-actinin) = on inner surface of cell membrane Thin myofilaments may be attached to dense bodies |
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Term
| Smooth Muscle Contraction |
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Definition
1a. Ca/calmodulin binds to caldesmon 1b. Tropomyosin changes location (ATP stimulated) essentially caldesmon replaces troponin as a calcium 2. Ca/calmodulin activates MLCK 3. MLCK phosphoylates myosin p-light chains 4. Myosin p-light chains activate ATP activity Both phosphorylation of myosin p-light chains and removal of caldesmon from thin filaments required for contraction |
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Term
Sliding Fliament Theory Smooth Muscle |
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Definition
1. Thin slide over thick 2. Transmitted to dense bodies and intermediate filaments 3. Transmitted to attachment plaques at cell membrane 4. Inward pulling of cell membrane changes cell shape 5. Change in shape of several cells = muscle contraction |
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Term
| Cardiac Muscle Regeneration |
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Definition
Almost no regeneration beyond early childhood
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Term
| Ischemia and Heart Attack |
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Definition
Ischemia (reduction of blood supply) results in replacement of cardiac muscle by dense coolagenous fiberous connective tissue (myocardial infraction)
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Term
| Skeletal Muscle Regeneration |
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Definition
Limited regeneration from satellite cells (spindled cells with basal lamina) |
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Term
| Smooth Muscle Regeneration |
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Definition
Active regeneration by mitosis in surviving smooth muscle cells
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