Lecture 11: Sensory Neurons and Receptors

These flashcards cover the key concepts related to sensory neurons, receptor types, and functions discussed in Lecture 11.

1st Order Sensory Neuron

Typically synapses with spinal cord or brainstem; encodes type of stimulus, intensity, location, duration.

2nd Order Sensory Neuron

Located in spinal cord or brainstem sensory nuclei; functions to relay, process, and cross information to the opposite side.

3rd Order Sensory Neuron

Found in the thalamus; it relays signals to the sensory cortex and sensory info.

Thalamus

Receives all sensory input except olfaction; relays it to appropriate cortical areas.

Cerebrum

Processes sensory stimuli; integrates, interprets, and gives context.

Cerebellum

Coordinates fine motor control and precision movement; maintains posture and balance.

Sensation

Transmission of stimuli information to the CNS.

Perception

Occurs in the cerebral cortex.

4 types of sensory receptors

Free nerve endings, encapsulated nerve endings, specialized receptor cells, photo receptors

Examples of exteroreceptors

Mechano/thermo/photo/olfactory taste

Examples of internoreceptors

Chemo/baro/stretch

Examples of proprioceptors

Muscle spindles, vestibular hair cells

Receptor Potential

Stimulus activates specialized receptor cell resulting in a graded change in membrane potential. → ca influx → n.t releases→depolarization

Generator Potential

A graded potential that reaches threshold and generates action potential.

Exocrine Glands

Glands such as sweat glands and sebaceous glands.

Merkel Cells

Respond to light touch and texture. Tonic

Meissner's Corpuscles

Phasic receptors for light touch and low frequency vibrations.

Ruffini Endings

Detect skin stretch and sustained pressure. Tonic

Pacinian Corpuscles

Phasic receptors for deep pressure and high frequency vibrations.

Cold Receptors

Active below 35°C.

Warm Receptors

Active between 30 to 45°C.

Chemoreceptors

Detect chemical stimuli and convert them to neural signals.

Extreme cold

TRPA 1

Extreme heat

TRPV I