Term
| Where is smooth muscle located? |
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Definition
located in the walls of hollow organs.
-tunica media of blood vessels
-digestive, respiratory tract
-in skin arector pili |
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Term
| Where is the tunica media derived from |
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Definition
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Term
| the intermediate filaments found in the smooth muscle of blood vessels |
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Definition
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Term
| what is visceral smooth muscle derived from |
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Definition
| from the embryonic lateral plate and splanchopleural mesoderm |
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Term
| the intermediate filaments of visceral smooth muscle |
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Definition
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Term
| the strucure of smooth muscle |
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Definition
form layers or bundles around hollow organs
orthogonal arrangement of layers |
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Term
| describe the shape of the smooth muscle cells |
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Definition
| spindle shaped or fusiform |
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Term
| Where actin filaments attach in smooth muscle |
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Definition
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Term
| the type of rhythm found in smooth muscles |
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Definition
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Term
| how is the nerve impulse delivered to smooth muscle cells and how is it transmitted from cell to cell. |
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Definition
the nerve endings lie nearby but ni synapses are formed.
gap junctions transmit the impulses from cell to cell |
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Term
| Describe the contrile appartatus of smooth muscle |
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Definition
Actin filaments radiate from dense bodies
Myosin filaments found between and overlapping actin. Form “on demand.”
Dense bodies are attached to one another by intracellular protein bridges; serve as “Z lines” |
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Term
| How is the intrinsic rhythm of smooth muscle modulated |
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Definition
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Term
| how is the contraction of smooth muscle regulated |
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Definition
| regulated by the phosphorylation of one of the myosin light chains (regulatory light chaim) |
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Term
| How is the thin filament of skeletal muscle different from smooth muscle |
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Definition
| smooth muscle does not have troponin only tropomyosin |
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Term
| Describe myosin activation in smooth muscle |
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Definition
1. an increase in calcium causes calmodulin to bind to myosin light-chain kinase.
2. the now activated ca-calmodulin-myosin light chain kinase phosphorylates the myosin light chain
3. Inactive myosin is converted to active myosin which then binds to F-actin |
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Term
| types of smooth muscle connections and organizations |
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Definition
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Term
a type of smooth muscle with the following traits:
1. APs not common because the fibers are too small
2. ANS stimulation throgh varicosities that release ACh/NE that causes local depolarization "junctional potential" that spreads over the fibers causing contractions.
3. Examples: Iris, cillary muscles of the eye, vas deferens, pilorector muscles
4. fine motor control |
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Definition
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Term
a type of smooth muscle with the following traits:
1. cells form hollow tubes-sheets of cells
2. APs normally occur; 30-40 muscle fibers must depolarize simultaneously before the AP occurs
3. Gap Junctions permit coordinated contraction where they can exchange cytoplasmic interaction
4. GI tract, bile ducts, bladder, ureter, uterus, blood vessels |
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Definition
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Term
| Types of visceral smooth muscle that has plateau action potentials |
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Definition
| uterus, ureter, vascular smooth muscle |
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Term
| Why is repolarization delayed in plateau smooth muscle AP |
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Definition
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Term
| APs that are elicited without extrinsic stimulation. like in the gut and intestinal wall |
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Definition
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Term
| What produces low oscillation of RMP that do not reach threshold unless strong enough |
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Definition
| slow waves AKA pacemaker waves |
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Term
| What occurs if slow wave potential reaches threshold (-35mV) causing trains of AP |
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Definition
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Term
| pacemakers for the electrical and contractile activity of smooth muscle |
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Definition
| interstitial cells of Cajal |
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Term
| Where is calcium stored in smooth muscle? |
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Definition
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Term
| A type of contraction characterized by a twitch like shortening followed by relaxation |
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Definition
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Term
a type of contraction caused by a force sustained for a very long period. THis leads to the ability to maintain force of contraction with a decreased number of activated crossbridges greatly reducing levels of energy consumption
more energy efficient |
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Definition
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Term
| How is length-tension relationship different in smooth muscle versus skeletal |
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Definition
in smooth muscle tension can be developed over a greater range of lengths.
can create tension with even large increases in organ volume. Example: stomach, bladder |
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Term
| What processes lead to an increase in cytoplasmic calcium and promote contraction? |
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Definition
1. leak channels
2. voltage gated channels
3. ligand gated channels
4. IP3-gated SR Ca channels |
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Term
| What processes lead to a decrease in internal calcium promoting relaxation? |
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Definition
1. Ca ATPase
2. Ca/Na Exchanger |
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Term
A disorder caused by abnormal spasm of vascular smooth muscle in peripheral tissue. Leads to diminished blood supply to local tissue.
Skin discoloration upon temperature or emotional changes: initially, digit(s) involved turn white due to diminished blood supply. The digit(s) then turn blue because of prolonged lack of oxygen. Finally, the blood vessels reopen, causing a local "flushing" phenomenon, which turns the digit(s) red |
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Definition
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