A&P II

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Receptor

Structure specialized to detect a stimulus.

Sense Organ

Combination of nerve tissue and accessory tissues.

Transduction

Conversion of stimulus energy into nerve signals.

Sensation

Detection of stimulus creating local electrical change.

Perception

Conscious interpretation of sensory stimuli.

Modality

Type of stimulus or perception produced.

Location

Where a stimulus is detected by nerve fibers.

Intensity

Strength of a stimulus measured by various factors.

Duration

Length of time a stimulus is present.

Receptive Field

Area where a sensory neuron detects stimuli.

Sensory Adaptation

Decreased awareness of a prolonged stimulus.

Phasic Receptors

Adapt quickly, signaling only at stimulus onset.

Tonic Receptors

Adapt slowly, signaling continuously while stimulus is present.

Photoreceptors

Respond to light, providing vision sense.

Thermoreceptors

Detect heat and cold stimuli.

Nociceptors

Respond to tissue injury and pain.

Labeled Line

Pathway transmitting specific modality information to CNS.

Firing Frequency

Rate of action potentials indicating stimulus intensity.

Receptor Potential

Small electrical change in response to stimulus.

Fine Two-Point Discrimination

Ability to distinguish between two close stimuli.

Accessory Tissues

Additional structures enhancing receptor response.

Action Potentials

Electrical impulses generated by neurons.

Neurons in Fingertips

Have small receptive fields for high resolution.

Chemoreceptors

Respond to chemical stimuli like odors and tastes.

Mechanoreceptors

Detect physical deformation such as touch and pressure.

Thermoreceptors

Respond to heat and cold sensations.

Nociceptors

Detect noxious stimuli causing pain.

Analgesia

Inability to feel pain.

Hypergesia

Increased sensitivity to pain.

Type A Axons

Large myelinated fibers for fast pain transmission.

Type C Axons

Small unmyelinated fibers for slow pain transmission.

Tactile Receptors

Sensitive receptors for fine touch and pressure.

Crude Touch Receptors

Less sensitive, large receptive field for touch.

Baroreceptors

Monitor changes in pressure in organs.

Proprioceptors

Monitor joint position and muscle tension.

Carotid Bodies

Monitor blood pH, CO2, and O2 levels.

Aortic Bodies

Located in aortic arch, monitor blood gases.

Free Nerve Endings

Basic receptors for pain and temperature.

Phasic Receptors

Adapt quickly to changes in stimulus.

Receptive Field

Area monitored by a single sensory receptor.

Joint Capsule Receptors

Detect pressure and movement in joints.

Golgi Tendon Organs

Monitor tension in tendons during muscle contraction.

Adaptation

Decreased sensitivity to a constant stimulus.

Reticular Formation

Brainstem area involved in pain pathways.

Primary Sensory Cortex

Brain area processing sensory information.

Somatic Reflexes

Involuntary responses triggered by sensory input.

Mechanically-Gated Ion Channels

Open in response to physical distortion.

Muscle Spindles

Monitor skeletal muscle length; trigger stretch reflexes.

Somatosensory Receptors

Detect stimuli related to touch, pressure, pain.

Unencapsulated Nerve Endings

Dendrites without connective tissue wrapping.

Free Nerve Endings

Tonic receptors for temperature and pain detection.

Tactile Discs

Flattened nerve endings detecting light touch and texture.

Hair Receptors

Dendrites around hair follicles; respond to hair movement.

Encapsulated Nerve Endings

Nerve fibers wrapped in glial cells or connective tissue.

Tactile Corpuscles

Detect fine/light touch; concentrated in hairless skin areas.

End Bulbs

Sensory fibers in connective tissue; similar to tactile corpuscles.

Bulbous Corpuscles

Tonic receptors detecting heavy touch and skin stretching.

Lamellar Corpuscles

Detect deep pressure and vibration; sensitive to high-frequency.

Exteroceptors

Sense stimuli from outside the body.

Interoceptors

Detect internal stimuli like pressure and visceral pain.

Proprioceptors

Sense body position and movements; located in muscles.

General Senses

Widely distributed receptors for touch, pain, temperature.

Special Senses

Limited to head; involve complex sense organs.

Afferent Division

Transmits sensory information to the central nervous system.

Tonic Receptors

Adapt slowly; respond continuously to stimuli.

Phasic Receptors

Adapt quickly; respond to changes in stimuli.

Nociceptors

Pain receptors; detect harmful stimuli.

Dermal Papillae

Structures in skin; contain tactile corpuscles.

Visceral Pain

Pain originating from internal organs.

Sensory neurons

Relay sensory information to the CNS.

Sensory pathways

Nerves and tracts delivering sensory info to CNS.

Efferent Division

Sends commands from CNS to effectors.

Nuclei

Clusters of cell bodies in the CNS.

Motor neurons

Transmit commands to effectors via axons.

Somatic Nervous System

Controls voluntary skeletal muscle movements.

Autonomic Nervous System

Regulates involuntary commands to organs.

First-order neuron

Transmits signals from receptors to CNS.

Second-order neuron

Crosses to opposite side, relays signals.

Third-order neuron

Connects thalamus to primary sensory cortex.

Projection pathway

Route for sensory signals to cerebral cortex.

Spinothalamic pathway

Carries crude touch, pain, and temperature sensations.

Posterior column pathway

Transmits fine touch and proprioception signals.

Spinocerebellar pathway

Conveys proprioceptive information to cerebellum.

Tracts

Bundles of axons within the CNS.

Nerves

Bundles of axons in the PNS.

Dorsal root

Entry point for sensory signals to spinal cord.

Decussate

Crossing over of nerve fibers.

Cerebellum

Coordinates voluntary movements and balance.

Thalamus

Relay station for sensory information.

Interneurons

Connect sensory and motor pathways in CNS.

Somatosensory Cortex

Processes sensory information from the body.

Posterior Column Pathway

Carries fine touch, pressure, vibration, proprioception.

First-order Neurons

Enter spinal cord, synapse at medulla.

Second-order Neurons

Cross to contralateral side, ascend to thalamus.

Third-order Neurons

Located in thalamus, send information to cortex.

Spinocerebellar Pathway

Transmits proprioceptive information to cerebellum.

Proprioception

Sense of body position and movement.

Pain

Unpleasant perception of tissue damage.

Nociceptive Pain

Results from activation of nociceptors.