Nervous System Core Concepts and Functions

Afferent division

Sensory input to the CNS

Efferent division

Motor output from the CNS

Somatic nervous system

Voluntary control of skeletal muscles

Autonomic nervous system

Involuntary control of smooth muscle, cardiac muscle, and glands

Small receptive field

Greater sensitivity

Tonic receptors

Slow adapting receptors (e.g., pain)

Phasic receptors

Fast adapting receptors (e.g., smell)

Special senses

Vision, hearing, equilibrium, taste, smell

General senses

Temperature, pain, touch, pressure, vibration, proprioception

Sensation vs. perception

Sensation is signal arrival; perception is awareness of the signal

Nociceptors

Pain

Thermoreceptors

Temperature

Mechanoreceptors

Physical distortion such as pressure or stretch

Chemoreceptors

Chemical changes like pH or CO?

Merkel cells

Light touch

Baroreceptors

Pressure in blood vessels

Proprioceptors

Body position and movement

Spinothalamic pathway

Pain, temperature, and crude touch

Posterior column pathway

Fine touch, vibration, proprioception

Spinocerebellar pathway

Proprioceptive input

Referred pain

Pain perceived in an unrelated body area

Phantom pain

Pain felt in a missing limb due to cortical rewiring

Corticospinal pathway

Voluntary control of skeletal muscles

Medial pathway

Subconscious control of posture and balance

Lateral pathway

Control of distal limb muscles

Corticobulbar pathway

Voluntary movement via cranial nerves

Motor homunculus

A map of the body on the motor cortex

Basal nuclei

Filtering and refining movements

Cerebellum

Coordination and balance