Somatic Nervous System

Somatic Nervous System

Part of PNS controlling voluntary movements.

Effectors

Skeletal muscles act as effectors for SNS.

Sensory Integration

Process of detecting and interpreting sensations.

Sensory Receptors

Cells that detect stimuli and send signals.

Exteroceptors

Receptors near the surface for external stimuli.

Interoceptors

Receptors monitoring internal organ stimuli.

Proprioceptors

Receptors monitoring body position and movement.

Nociceptors

Detect pain from tissue damage or intense stimuli.

Thermoreceptors

Detect temperature changes above or below normal.

Photoreceptors

Light-detecting cells located in the retina.

Mechanoreceptors

Detect physical stimuli like pressure and vibration.

Chemoreceptors

Respond to chemical stimuli like taste and smell.

Osmoreceptors

Monitor solute concentrations in body fluids.

Receptive Field

Area monitored by a specific sensory receptor.

Action Potential (AP)

Electrical signal transmitted by sensory receptors.

Spinal Cord

Central nervous system structure transmitting signals.

Brain Stem

Connects brain to spinal cord, regulates vital functions.

Ascending Pathway

Carries sensory information to the brain.

Dorsal Column System

Pathway for touch and proprioception signals.

Spinothalamic Tract

Carries pain and temperature sensations.

Fasciculus Gracilis

Transmits signals from legs and lower body.

Fasciculus Cuneatus

Transmits signals from arms and upper body.

Dorsal Root Ganglion

Cluster of sensory neuron cell bodies.

Medulla

Part of brainstem, relays sensory information.

Thalamus

Brain region processing and relaying sensory info.

Primary Motor Cortex

Frontal lobe region controlling voluntary movements.

Precentral Gyrus

Location of primary motor cortex in the brain.

Cortical Processing

Integration of sensory information in the cortex.

Sensory Homunculus

Map of body sensory receptors in the cortex.

Secondary Motor Cortices

Areas aiding in planning and coordinating movements.

Premotor Cortex

Coordinates movements of core muscles.

Supplemental Motor Area

Plans and coordinates complex movements.

Corticobulbar Tract

Pathway from motor cortex to brainstem.

Corticospinal Tract

Pathway from motor cortex to spinal cord.

Betz Cells

Large neurons in primary motor cortex.

Extrapyramidal System

Motor control system outside corticospinal pathways.

Ventral Horn

Spinal cord region containing lower motor neurons.

Neuromuscular Junction

Synapse between motor neuron and muscle fiber.

Reflexes

Automatic responses to stimuli, spinal or cranial.

Withdrawal Reflex

Protective reflex removing body part from harm.

Stretch Reflex

Muscle contraction in response to stretching.

Sensory Receptors

Cells detecting environmental stimuli.

Free Nerve Endings

Sensory receptors for pain and temperature.

Encapsulated Endings

Receptors enhancing sensitivity in connective tissue.

Photoreceptors

Specialized cells in retina for light detection.

Sensory neurons

Neurons that transmit sensory information to the brain.

Free nerve endings

Unencapsulated sensory receptors for pain and temperature.

Encapsulated endings

Specialized sensory receptors enclosed in connective tissue.

Photoreceptors

Specialized cells in the eyes detecting light.

Rod cells

Photoreceptors sensitive to low light conditions.

Bipolar cell

Intermediary neuron connecting photoreceptors to optic nerve.

Optic nerve neurons

Neurons transmitting visual information to the brain.

General sense

Distributed throughout body; includes touch, proprioception.

Visceral sense

Autonomic-related sensory perception.

Special sense

Specific organ dedicated to sensory function.

Gustation

Taste sensation associated with the tongue.

Umami

Savory taste; detected by L-glutamate.

Taste buds

Contain gustatory receptor cells for taste.

Papillae

Raised bumps on tongue housing taste buds.

Salty taste

Perception of sodium ions; sensory neuron depolarization.

Sour taste

Perception of H+ ions; indicates acidity.

Bitter taste

Food molecules bind to G protein coupled receptors.

Sweet taste

Glucose and similar sugars activate taste receptors.

Olfaction

Smell sensation associated with the nose.

Olfactory tract

Axons connecting olfactory receptors to olfactory bulb.

Audition

Hearing sensation associated with the ear.

Auricle

External ear structure directing sound waves.

Ossicles

Three small bones in the middle ear.

Cochlea

Inner ear structure containing receptor cells for hearing.

Vestibule

Inner ear structure regulating balance.

Hair cells

Mechanoreceptors detecting sound frequency vibrations.

Tympanic membrane

Ear drum vibrating in response to sound waves.

Retina

Contains nervous tissue for photoreception in the eye.

Fovea

Center of retina with high photoreceptor concentration.

Photoreceptors

Rods and cones responsible for light detection.