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25 Cards in this Set
- Front
- Back
How many types of Joint receptors are there? |
Four types! 3 are capsulated and convey information about joint position and movement 1 is non-capsulated and conveys excessive movements and pain |
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What do Neuromuscular (muscular) spindles do? |
found inside skeletal muscle near the tendons and convey sensory information to the CNS about muscle activity |
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Anatomy of a muscular spindle |
The Spindle is surrounded intrafusal Muscle fibers, which is encased by a Capsule. Extrafusal fibers are outside the capsule |
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What are the two types of intrafusal fibers? |
Nuclear bag - have nuclei in equitorial area and the fibers go beyond the capsule and are attached to extrafusal fibers Nuclear chain - One row of of nuclei in center |
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What are the two types of Muscle spindle innervation? |
Annulospiral endings- At the distal end of a large myelinated fiber that pierces the capsule which becomes unmyelinated and spin around the equator of intrafusal muscle fibers Flower spray endings- Also has unmyelinated ends that attach to nuclear chain fibers away from equator and looks like a flower spray |
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What happens when a muscle is stretched? |
Stimulates both annulospiral and flower spray afferent endings --> convey to spinal cord --> Gamma motorneurons are activated and stimulate contraction of Intrafusal fibers --> this activates sensory endings and activates Alpha Motorneurons that innervate extrafusal muscle --> causing contraction |
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What do Alpha and gamma motorneurons do? |
Alpha motorneurons- Innervate the Extrafusal muscle for contraction Gamma motorneurons- Innervate the intrafusal fibers for contraction |
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What is the function of the muscle spindle? |
Indirectly influences control over voluntary muscle Convey length information to CNS to determine position of body parts |
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What do gamma efferents do? |
Shorten the intrafusal fibers --> causes a reflex contraction of extrafusal fibers |
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What do Nuclear bag fibers ad Nuclear chain do? |
Nuclear Bag- Give information about the position and velocity of contraction Nuclear Chain- slow static contractions of voluntary muscles |
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Stretch reflex |
When the intrafusal fibers get stretched causing stimulation of the annulospiral and flower spray endings --> causes afferent signal sent to Spinal cord to synapse on Alpha motoneurons --> causing contraction the Extrafusal fibers (The whole muscle) |
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Monosynaptic reflexes |
Only involve afferent and Alpha motoneuron (one synapse) Fastest reflex Knee jerk reflex |
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Reciprocal inhibition |
Muscles on one side relaxing in order for the contracted muscle to continue movement |
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5 Essential components of the Reflex arc |
1.Receptor 2. Sensory neuron 3. Integration center: 1 or more synapses in CNS 4. Motor neuron: conducts efferent signals to effector 5. Effector: Contracts or secretes |
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Golgi tendon organ/Neurotendinous spindles detect..... |
Detects changes in muscle tension and length |
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Function of Golgi tendon organ/Neurotendinous spindles |
Neurotendinous reflex that inhibits muscle contraction so that it won't get too much tension and tear |
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3 motor nerve types that innervate muscles |
1. Large Alpha fibers (Myelinated) --> inn. Extrafusal 2. Small Gamma fibers (Myelinated) --> Inn. Intrafusal 3. Thin C fibers (nonmyelinated) --> postganglionic autonomic efferents for smooth muscle of blood vessels |
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3 sensory nerve types that innervate muscles |
1. Myelinated fibers of muscular spindle --> Annulospiral and Flower Spray endings 2. Myelinated fibers of Gogli tendon organ/Neurotendinous spindle 3. Myelinated and non-myelinated fibers that are from other sensory endings in connective tissue |
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Hyperreflexia |
Caused by Upper Motor Neuron Damage |
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Areflexia or Hyporeflexia |
Lower Motor Neuron damage |
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Neuromuscular junction in smooth muscle |
Non-Myelinated and pass through the muscle like a train with terminals Cholinergic nerves --> Ach released Adrenergic nerves --> Norepinephrine |
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Digestive system is Innervated by two plexuses... |
The submucosal flex us of Meissner and the Myenteric plexus of Auerbach (parasympathetic) |
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Dermatomes |
Nipple --> Lower T4/T5 Navel --> T10 |
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Gillian-Barre Syndrome |
An Acute Polyneuropathy Segmental demyelination --> muscle weakness and paresthesia from legs to the arms Possible Respiratory paralysis |
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Roots of Reflexes of...... Biceps Brachii Reflex Triceps reflex: Brachioradialis reflex: Abdominal reflexes: Patellar Reflex (Knee jerk): Achilles tendon reflex (Ankle jerk): |
Biceps Brachii Reflex --> C5-C6
Triceps reflex --> C7-C8 Brachioradialis reflex --> C5-C6 (same as biceps) Abdominal reflexes --> Upper T6-7, Mid T8-9, Lower T10-12 Patellar Reflex (Knee jerk) --> L3-L4 Achilles tendon reflex (Ankle jerk) --> S1-S2 |