Term
| where is smooth muscle located? |
|
Definition
- blood vessels
- hollow organs: respiratory tract, GI tract, urinary system, reproductive system |
|
|
Term
| small intestine has an outer ___ layer of smooth muscle and an inner ___ layer of smooth muscle. |
|
Definition
|
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Term
|
Definition
- fusiform
- spindle shaped
- no connective tissue sheath
- fine endothelium
- no striations or sarcomeres
- single centrally located nucleus
- sarcolemma with caveoli, dense bodies, receptors, ion channels, and pumps
- mitochondria- near nucleus |
|
|
Term
| Smooth muscle has or does not have an organized tubular system? |
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Definition
| SMOOTH MUSCLE DOES NOT HAVE AN ORGANIZED TUBULAR SYSTEM |
|
|
Term
| Is the sarcoplasmic reticulum more abundant in smooth muscle or skeletal muscle? |
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Definition
|
|
Term
| smooth muscle cells are inbedded in a __tissue. |
|
Definition
|
|
Term
| smooth muslce cells are arranged how? |
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Definition
| - arranged in sheets of closely apposed fibers |
|
|
Term
| what are the contractile filaments of smooth muscle? |
|
Definition
- thick (myosin)
- thin (actin and tropomyosin, but NO TROPONIN)
- intermediate: desmin, vimentin
- |
|
|
Term
| what contractile filament does skeletal muscle have that smooth muscle does not have? |
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Definition
|
|
Term
| The ratio thick to thin filaments in smooth muscle is ___ than the ratio is skeletal muscle. |
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Definition
|
|
Term
| In smooth muscle, thick and thin filaments are arranged ___ causing the muscle to contract in a ___ fashion. |
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Definition
|
|
Term
| dense bodies in smooth muslce are analogous to __ ___ in skeletal muscle |
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Definition
|
|
Term
| In smooth muscle, noncontractile intermediate filaments attach to the ___ ___. |
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Definition
|
|
Term
| With smooth muslce, myosin has heads where? |
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Definition
| - thick myosin filaments in smooth muscle have heads all along the filament |
|
|
Term
| dense bodies in smooth muscle is where ___ attaches. |
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Definition
|
|
Term
| smooth muscle has lots of ___ ___ for communication, specifically ephaptic conduction of ____ signals and functional syncitium |
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Definition
|
|
Term
| smooth muscle will contract in response to: |
|
Definition
Nerve stimulation
Hormonal stimuli
Pharmacologic stimuli
Presence or lack of metabolites
Cold (temperature)
Pressure
Stretch
Touch
Spontaneous activity as well |
|
|
Term
| when skeletal muscle is stimulated it always ___, but smooth muscle can either ___ or relax when stimulated |
|
Definition
- contracts
- contract or relax |
|
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Term
| large blood vessels, the stomach,and intestines have ___ ___ cells that spontanelously depolarize, which spreads through ___ ___. |
|
Definition
- pacemaker
- gap junctions |
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|
Term
| a hyperpolarized muscle will contract with less ___. |
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Definition
|
|
Term
| In smooth muscle the depolarization phase is due to the entry of ___, while in skeletal muscle depolarization is due to the entry of ___. The repolarization phase of both smooth and skeletal muscle is due to the exit of ___. |
|
Definition
|
|
Term
| smooth muscle is always partially ___ |
|
Definition
|
|
Term
| Single-unit smooth muscle is called this b/c all the individual cell fibers conctract as a __ ___. This is also called ___ ___ ___. All the fibers in single unit smooth muscle are ___ ___ to each other, so an action potential will spread rapidly through __ ___ so that entire sheet of muscle will contract. All fibers contract every time with single unit smooth muscle, so the amount of ___ that enters the cell determines the ___ of contraction. |
|
Definition
- single unit
- visceral smooth muscle
- electrically connected
- gap junctions
- calcium
- force |
|
|
Term
| mutli-unit smooth muscle consists of cell that are not ___ ___. Thus each individual muscle fiber must be closely associated with an ___ __ or ___ and stimulated ___. This arrangement allows for __ contraction through selective activation. As in skeletal muscle, increasing force requires recruiting __ __. |
|
Definition
- not electrically connected
- axon terminal or variscosity
- individually
- fine
- additional fibers |
|
|
Term
| where is multiunit smooth muscle found? |
|
Definition
- iris
- ciliary body
- male reproductive tract
- uterus but not at end of pregnancy |
|
|
Term
| Smooth muscle has _____ junctions not ___ ___ plates like skeletal muscle. |
|
Definition
- neuroeffector junctions
- motor end plates |
|
|
Term
|
Definition
| - synapse between a postganglionic autonomic neuron and its target cell (in this case smooth muscle) |
|
|
Term
| an autonomic neuron is unique b/c they have swellings at their distal ends called ___ which contain vesicles filled with ____. But the target cell does not have neurstranmitter receptors at specific sites so the neurotransmitter diffuses wherever the receptors are. |
|
Definition
- varicosities
- neurotransmitter |
|
|
Term
| variscosities on autonomic neurons release their neurotransmitter in response to: |
|
Definition
|
|
Term
| the neurotransmitter may be: |
|
Definition
| - excitatory or inhibitory |
|
|
Term
| few muscle cells actually get direct contact with the neurotransmitter, so the rest of the smooth muscle fibers are stimulated by gap junction communication |
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Definition
|
|
Term
| the final trigger for contraction of smooth muscle in a rise in __ calcium. actin and myosin still contract according to sliding filament theory. |
|
Definition
|
|
Term
| caclium is released from the SR and from the ___ space. |
|
Definition
|
|
Term
| In smooth muscle, calcium interacts with ___and ___ ___ __ ___to activate ___. |
|
Definition
- calmodulin
- myosin light chain kinase
- myosin |
|
|
Term
| describe process of smooth muscle contraction: |
|
Definition
| - either a hormone binds to its receptor or depolarization of the cell membrane opens calcium ion channels in the plasma membrane> calcium ions diffuse into the cell via calcium ion channels and combine with calmodulin> calmodulin with calcium bound to it, binds to myosin kinase and activates it> myosin kianse phosphorylates the myosin heads with ATP> cross bridge attachment, movement and detachment occurs> myosin phosphatase removes phosphate from myosin= relaxation |
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|
Term
| alpha 1 receptors, found in most sympathetic target tissues, bind ___, which activates ____ which results in increased ___, leading to ___. |
|
Definition
- NE
- IP3
- calcium
- contraction |
|
|
Term
| alpha 2 receptors, in the gastrointestinal tract and pancreas, bind ___ and decrease ___ resulting in ___. |
|
Definition
- NE
- decrease cAMP
- relaxation |
|
|
Term
| beta 1 receptors, which are in certain blood vessels and smooth muscle of some organs, binds ___ and ___, causing a decrease in ___, resulting in ___. |
|
Definition
- NE and Epi
- cAMP
- relaxation |
|
|
Term
| beta receptors work by increasing/decreasing ____, while alpha receptors work by activating ____ which creates ____. |
|
Definition
- cAMP
- phospholipase C, IP3 |
|
|
Term
| Both alpha and beta receptors are ___ receptors and are associated with the ___ nervous system. |
|
Definition
- adrenergic
- sympathetic |
|
|
Term
| muscarinic receptors bind ____ and are associated with the ___ nervous system. |
|
Definition
- acetylcholine
- parasympathetic |
|
|
Term
| visceral aka single unit smooth muscle: |
|
Definition
Contract rhythmically as a unit
Are electrically coupled to one another via gap junctions
Cells capable of generating inherent spontaneous activity (without neural input)
Normally responds to stretch - exhibit stress-relaxation response
Location: hollow organs of blood vessels, G.I., urinary, reproductive, and respiratory systems |
|
|
Term
| where is single unit smooth muscle located? |
|
Definition
- hollow organs
- blood vessels
- GI tract
- repdroductive tract
- urinary sytem
- respiratory system |
|
|
Term
| single unit smooth muscle can generate ___ ___ ___ without ___ ___. |
|
Definition
-inherit spontaneous activity
- without nerural input |
|
|
Term
| multiunit smooth muscle : |
|
Definition
Rare gap junctions - cells not electrically connected
Muscle cells structurally independent of each other
Infrequent spontaneous depolarizations
Each cell innervated
Rich nerve supply, which, with a number of muscle fibers, forms motor units
Respond to autonomic neural and humoral stimulation with graded contractions
Fine control
Location: large airways to the lungs, large arteries, in arrector pili muscles (attached to hair follicles) internal eye muscles |
|
|
Term
| where is multiunit smooth muscle found? |
|
Definition
- large airways to lungs
- large arterioles
- arrector pilli muscles
- internal eye muscles |
|
|
Term
| smooth muscle has very slow or very fast myosin atpase activity? |
|
Definition
| - very slow myosin ATPase in smooth muscle |
|
|
Term
| special characteristics of smooth muscle: |
|
Definition
Smooth muscle tone
Slow, prolonged contractile activity
Low energy requirements
Response to stretch |
|
|
Term
| b/c smooth muscle does not have sarcomeres and is not attached to bone, it has a greater ___ ___ than skeletal muscle. |
|
Definition
|
|
Term
| smooth muscle can operate at longer ___ of lenght (___%) than skeletal muscle (___%). |
|
Definition
| - ranges of length (150% for smooth muscle, 60% for skeletal muscle) |
|
|
Term
| at the same CSA, smooth muscle can develop the same amount of ___ as skeletal muscle. |
|
Definition
|
|
Term
| smooth muscle exhibits stress-relaxation response, explain this: |
|
Definition
- smooth muscle responds to stretch only briefly, and then adapts to new length
- the new length retains its ability to contract
- this allows organs like ths stomach and bladder temporary storage of contents |
|
|
Term
| with the stress-relaxation response, if you stretch to a new length, you ___ initial force, ie the ____ response, but this is followed by a ___ in force. |
|
Definition
- increase initial force
- elastic response
- decrease |
|
|
Term
|
Definition
| - exposure to constant force> slow elongation to new length- this is creeping |
|
|
Term
| t tubules in skeletal muscles are at what junctions? does smooth muscle have t tubules? |
|
Definition
A- I
no, smooth has caveolae instead |
|
|
Term
| does skeletal, cardiac, or smooth have the most elaborate SR? |
|
Definition
|
|
Term
| explain what types of muscle gap junctions are in: |
|
Definition
- skeletal= no gap junctions
- cardiac= gap junctions at intercalated discs
- smooth= gap junctions in single unit smooth muscle |
|
|
Term
| what types of muscle have individual neuromuscular junctions? |
|
Definition
- skeletal
- multiunit smooth muscle |
|
|
Term
| explain where each muscle type gets its calcium: |
|
Definition
- skeletal: SR
- cardiac: extracellular calcium
- smooth: extracellular calcium |
|
|
Term
| in skeletal and cardiac muslce, ___ regulates calcium. in smooth muscle, __ regulates calcium |
|
Definition
|
|
Term
| pace maker cells are in what types of muscle? |
|
Definition
- cardiac
- single unit smooth muscle |
|
|
Term
| what types of muscle have rhythmic contractions? |
|
Definition
- cardiac
- single unit smooth muscle |
|
|
Term
| describe each muscle types response to stretch: |
|
Definition
- skeletal: contractile strength increases with degree of stretch up to a point
- cardiac: contractile strenght increases with stretch
- smooth: stress-relaxation response |
|
|
Term
| smooth muscle and cardiac muscle use only aerobic respiration, skeletal muscle can use aerobic and anaerobic |
|
Definition
|
|
Term
| see slides 40-44 for good charts comparing muscle types |
|
Definition
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