Post on 17-Jan-2016
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LABORATORY SIX
Skeletal Muscle Physiology &
Neuroendocrine System
1
An Introduction to Electromyogram
• Muscle contraction begins with ion flow across the muscle cell membrane, causing depolarization of the muscle cell
• The flow of electrically charged ions causes electrical current
• Using electrodes, we can detect this current and visualize it with a computer - EMG
2
EMG TraceForearm flexors contraction by making a fist
3
Motor Unit Recruitment More grip force, more motor units
activation, more muscle fibers contraction, Successively higher EMG amplitude
3/10/2008 4
Electromyogram Recording
• Biopac Student software is used to look at graded response in a whole muscle
• Calibrate the software for each volunteer– Eliminate electrical noise– Normalize for each individual muscle action
• To see a graded response, the volunteer does a minimal (1/4), a small (1/2), a medium (3/4), and a full (4/4) grip force
• By increasing the grip force, you are activating more motor units
5
The Neuroendocrine System(homeostasis control)
• Nervous system (rapid & transient)
• Central• Peripheral
• Endocrine system (slow & long lasting)
The Endocrine System
Islets of Langerhans
Microscopic view of a group of cells in the pancreas that are endocrine in function
Neuron Anatomy
• Neurons: functional cells that transport electrical impulses
• Neuroglia: non-conductive – Schwann cells
• Reflex arc on P239
The Peripheral Nervous System
• Cranial Nerves - 12 pairs– Sensory (afferent) - carry impulses toward the CNS– Motor (efferent) - carry impulses away from the CNS– Mixed (both sensory & motor in a nerve bundle)– Located inferiorly, numbered in order, anterior to
posterior
• Spinal Nerves - 31 pairs– Mixed– Numbered based on the name and number of their
associated vertebrae
Cranial Nerves
Auditory
Spinal
(When studying the Cranial Nerves model, turn the
page 180o)
Memory Tool for Learning Cranial Nerves
Nerve Name FunctionOlfactory nerve I On Some (sensory)Optic nerve II Old Say (sensory)Oculomotor nerve III Olympus’ Marry (motor)Trochlear nerve IV Towering Money (motor)Trigeminal nerve V Top But (both S & M)Abducens nerve VI A My (motor)Facial nerve VII Finn Brother (both)Auditory nerve VIII And Says (sensory)Glossopharygeal nerve IX German Big (both)Vagus nerve X Viewed Brains (both)Spinal Accessory nerve XI Some Matter (motor)Hypoglossal nerve XII Hops More (motor)
Spinal Nerves(both sensory and motor
in function)
• Cervical (C1-C8)• Thoracic (T1-T12)• Lumbar (L1-L5) • Sacral (S1-S5)• Coccygeal (Co)
Plexuses
Collection of nerves that innervates a specific region of the body:
• Cervical: head & neck, diaphragm
• Brachial: upper limb• Lumbar: anterior thigh• Sacral: buttocks, lower
limb, and pelvis