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The Peripheral Nervous System

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Presentation on theme: "The Peripheral Nervous System"— Presentation transcript:

1 The Peripheral Nervous System
Key Note: The 12 pairs of cranial nerves are responsible for the special senses of smell, sight, and hearing/balance, and control movement of the eye, jaw, face, tongue, and muscles of the neck, back, and shoulders. They also provide sensation from the face, neck, and upper chest and autonomic innervation to thoracic and abdominopelvic organs.

2 The Cranial Nerves

3 The Peripheral Nervous System
The Spinal Nerves _________ __________ 12 Thoracic ___________ ____________—Region of the body surface monitored by a pair of spinal nerves

4 The Peripheral Nervous System
Nerve Plexus—A complex, interwoven network of nerves Four Large Plexuses _____________

5 Cervical Plexus C1-C4 ventral rami Some fibers from C5
Innervates muscles of the ___________ ______________ Phrenic nerve

6 Brachial Plexus Ventral rami of C5-T1
Innervates __________________________

7 Clinical Correlations
Erb-Duchene palsy waiter’s tip position fall on shoulder Radial nerve injury improper deltoid injection or tight cast wrist drop Median nerve injury numb palm & fingers; inability to pronate & flex fingers Ulnar nerve injury (clawhand) inability to adduct/abduct fingers, atrophy of interosseus Long thoracic nerve injury (winged scapula) paralysis of serratus anterior, can’t abduct above horizontal

8 The Brachial Plexus

9 The Cervical and Brachial Plexus

10 Lumbar and Sacral Plexuses
____________- ventral rami of T12–L4 ____________– ventral rami of L4–S4 Innervate pelvic girdle and lower limbs

11 The Lumbar and Sacral Plexuses,

12

13 The Autonomic Nervous System
Branch of nervous system that coordinates cardiovascular, ______________________, and reproductive functions Should the lower text be 30 pt?

14 The Autonomic Nervous System
Divisions of the ANS ______________ division neurons in the thoracic and lumbar segments of the spinal cord “Fight or flight” system ___________________ division neurons in the brain and sacral segments “Rest and digest” system

15 The Autonomic Nervous System
Key Note: The two divisions of the ANS operate largely without our awareness. The sympathetic division increases alertness, metabolic rate, and muscular abilities; The parasympathetic division reduces metabolic rate and promotes visceral activities such as digestion.

16 The Sympathetic Division

17 The Autonomic Nervous System
Effects of ___________ Activation Generalized response in crises ______________________ Feeling of euphoria and energy Increased cardiovascular activity __________________________ Increased muscle tone

18 The Parasympathetic Division

19 The Autonomic Nervous System
Effects of _____sympathetic Activation Relaxation _________________ Brief effects at specific sites

20 The Autonomic Nervous System
Relationship between the Two Divisions: Sympathetic division reaches visceral and somatic structures throughout the body Parasympathetic division reaches only visceral structures via cranial nerves or in the abdominopelvic cavity _________________________________ In general, the two divisions produce opposite effects on the their target organs

21 The Peripheral Nervous System
Key Note: Reflexes are rapid, automatic responses to stimuli that “buy time” for the planning and execution of more complex responses that are often consciously directed.

22 The Peripheral Nervous System
Reflex—An automatic involuntary motor response to a specific stimulus The 5 steps in a reflex arc Arrival of stimulus and activation of receptor ___________________________ CNS processing of information Response by effector (_______________)

23 Reflex Action Sensation relayed to the brain by collateral Dorsal root
Arrival of stimulus and activation of receptor Activation of a sensory neuron REFLEX ARC Receptor Stimulus Effector Ventral root Information processing in CNS Response by effector Activation of a motor neuron KEY Sensory neuron (stimulated) Excitatory interneuron Reflex Action Motor neuron (stimulated)

24 Stretching of muscle tendon stimulates muscle spindles Muscle spindle
(stretch receptor) Stretch Spinal cord REFLEX ARC Contraction Activation of motor neuron produces reflex muscle contraction Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

25 The Flexor Reflex

26 Aging and the Nervous System
Age-Related Changes Reduction in brain size and weight _______________ ______________________ Changes in synaptic organization of the brain Intracellular and extracellular changes in CNS neurons


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