RRECEPTORS

Classification of Nerves Mixed Nerves carry impulses both ot and from CNS contain both sensory and motor axons most common Sensory (affterent ) Nerves only toward the CNS rare – only three pair I. – Olfacatory II. Optic VIII. Vestibulocochlear Motor (efferent) Nerves only axons away from CNS rare – only 5 pairs of carainal nerves III. Oculmoror IV. Trochclear VI Abducens XI Accesory XII Hypoglossal

Sensory receptors – simple, unencapsulated exteroreceptors (nociceptors, thermoreceptors, mechanoreceptors)

Sensory receptors – simple, encapsulated exteroreceptors and interoreceptors (mechanoreceptors)

Sensory receptors – simple, encapsulated proprioceptors (mechanoreceptors)

Sensory Receptors (Chapter 12) Thermoreceptors – extremes cause pain receptors to respond Photoreceptors – rods and cones of the eye Mechanoreceptors Pressoreceptors Meissner's Pacinian baroreceptors

Proprioceptors – stretch receptors send information to CNS concerning lengths and tensions of muscles muscle spindle, golgi tendon

Pain receptors (nociceptors) pain exposure to excesses, free nerve endings visceral pain -> referred acute pain chronic pain

Receptors – Chemoreceptors taste, smell, changes in pH, oxygen and glucose

CENTRALCENTRAL NERVOUS SYSTEM TRACTS

White matter: ascending and descending tracts

Ascending pathway (nonspecific)

Direct pathway (pyramidal)

Indirect pathway (extrapyramidal)

Ascending pathway (specific)

Peripheral Nervous System

Nervous system organization

From sensation to perception Sensation is the awareness of changes in the internal and external environment Perception is the conscious interpretation of those stimuli

Neural integration Receptor level Circuit level Perceptual level

Motor control

Reflex arc

Stretch reflex

Flexor reflex (withdrawal reflex) pain contraction

Spinal Nerves

Spinal nerve organization and rami

Spinal nerve organization and rami

Dermatomes