class 3 the nervous system and somatic and special senses
TRANSCRIPT
Cranial Nerves•12 Pairs of nerves that originate on the brain.
I - Olfactory II - Optic III - Oculomotor IV - Trochlear V - Trigeminal VI - Abducens VII - Facial VIII - Auditory IX - Glossopharyngeal X - Vagus XI - Accessory XII - Hypoglossal
Spinal Nerves
• 31 pairs of spinal
nerves (mixed nerves)– 8 cervical (C1 – C8) C1
between skull and atlas– others exiting at
intervertebral foramen
– 12 thoracic (T1 – T12)
– 5 lumbar (L1 – L5)
– 5 sacral (S1 – S5)
– 1 coccygeal (Co)
Spinal cord
Anterior median fissure
Pia mater
Denticulateligaments
Dorsal root
Ventral root, formed byseveral “rootlets” fromone cervical segment
Arachnoid mater(reflected)Dura mater (reflected)
Spinal blood vessel
Receptor
Sensory neuron
Integration center
Motor neuron
Effector
Spinal cord(in cross section)
Interneuron
Stimulus
Skin
1
2
3
4
5
Reflex Arc
Nerve Plexus
• Where 2 or more nerves come together, are re-sorted, and form a new nerve
• Include:– Cervical– Brachial– Lumbosacral
Peripheral NervesPhrenic Nerve diaphragmAxillary Nerve armpitMedian Nerve** associated with carpal tunnel syndromeUlnar Nerve medial forearmRadial Nerve posterior arm, lateral forearm, posterior
handMusculocutaneous Nerve muscles and skin of armSciatic Nerve** posterior thigh to bottom of foot to big toe; splits into Tibial and Fibular at knee; largest
and longest nerve in the body; can oftenbeen impinged by the piriformis muscle
Femoral Nerve** anterior and lateral thighObturator Nerve pelvis
Cervical plexus Brachial plexus Lumbosacral plexus
Dermatomes • A dermatome is
a region of the skin supplied by a single spinal nerve.
C2C3
C2
C3 C3
C2C3
N V
C5
C5
C4
C4
C6
C7C6
T2
T1T2T3T4T5T6T7T8T9T10
T11
T12
T2T3T4T5T6T7T8T9T10T11T12L1L2
L3L4L5
L1
T1
T2
C8
C7
C8
L2
L3
L4
T1 L1
L2
L5
S5
S
S1
S2
4S3S2
S1
L3
L4
L5
ANTERIOR POSTERIOR
Sympathetic Division“Fight or Flight”
Thoracolumbar division it’s branches come from the
T₁ – L₂ or L₃
Effects
heart rate, breathing rate,sweating, pupil size, blood vessel size to skeletal muscle, adrenal gland secretions
intestinal function and saliva
Parasympathetic Division“Rest and Digest”
CranioSacral Division it’s branches come from
the CNs III, VII, IX, X and S₂, S₃, and S₄
Effects:•Increase Intestinal Activity and saliva•Decrease Heart Rate•Slower, deeper breathing•Constricts pupils
Role of Massage Therapy in Autonomic Nervous System Function
Stimulates a Parasympathetic
response
Relaxation!Relaxation!Relaxation!
Exception: Pre-event Massage/Sports Massage – which is
designed to “stimulate” the body to prepare it for the event about to take
place
Somatic and Special Senses
5 Types of Receptors:Chemoreceptors
Detect chemical concentrations in an aqueous solutionsex) taste buds and receptors of the nose
Pain ReceptorsDetect damage to tissueex) free nerve endings throughout body
ThermoreceptorsDetect changes in temperatureex) receptors found throughout skin and more
MechanoreceptorsDetect changes in pressure or movementex) receptors found in skin, inner ear and more
PhotoreceptorsDetect light energyex) rods and cones – the visual receptors
Sensations•All impulses (information) entering the CNS are virtually the same.
• The brain sends the signals to specific areas of the brain for interpretation.
•All sensation is subjective.
•Sensation is projected back to the site of the original stimulus, which makes us think we sense it at that point.
•Many senses will adapt, impulses rates will decrease.
Temperature Sensation2 categories of Thermoreceptors:
Hot and Cold receptors.
• Cold receptors – Most stimulated between 77º F and 41º F. Below that and area goes numb.
• Hot receptors – Perceive hot sensations above 86º F and are most stimulated at 113º F.
• Free Nerve Endings: Detect as burning sensation when temp is above 113⁰ or detect as numbing when temp is below 41⁰.
• Thermoreceptors are found all over the body, with highest concentration found in the face and ears (hence why your nose and ears always get colder faster than the rest of your body on a chilly winter day).
Pain Sensation• Acute Fibers (A-Delta
fibers)– sharp, myelinated,
remove stimulus & pain goes away
• Chronic Fibers (C fibers)– dull, unmyelinated,
remove stimulus & pain stays
Regulation of Pain Impulses
Endorphins and EnkephalinsOur Natural Pain Killers – special chemicals that when
released slow down the pain fiber impulses hence lessening pain.
• Hyperopia (farsightedness) – difficulty focusing on objects near the face.
• Myopia (nearsightedness) – difficulty focusing on distant objects.
• Astigmatism - An irregular shaped cornea or lens prevents light from focusing properly on the retina. Images focus at multiple points on retina
Static Equilibrium
• As the head moves, the thick fluid above the receptor cells, weighted with otoliths, pulls on the cilia of the cells, generating a nerve impulse
Dynamic Equilibrium
• As the body spins or moves in different directions, the cilia bend as the head changes position, generating nerve impulses.
This…….is….…JeopardyNervous System The BrainNeurons Senses
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Peripheral Nervous System