Sensory Receptors and Pathways(48-52pg)

Flashcards covering key concepts related to sensory receptors, their pathways, and functions.

What are the types of sensory receptors and their functions?

Mechanoreceptors (pressure, touch, vibration, stretch), Thermoreceptors (temperature changes), Photoreceptors (light), Chemoreceptors (chemicals), Nociceptors (pain).

Define receptor field.

A receptor field is the area of the body that one sensory neuron monitors; smaller fields = more precise touch.

What is the difference between tonic and phasic receptors?

Tonic receptors are always active and slow to adapt (e.g., pain), while phasic receptors are active only when a stimulus changes and adapt quickly (e.g., touch).

How does the brain distinguish between different sensory inputs?

The brain knows the type of sensation (e.g., pain vs. light) based on where the sensory signal ends in the brain.

Do all body areas have the same density of somatosensory receptors?

No, areas like fingertips and lips have high receptor density, while areas like the back have low density.

What is the somatosensory homunculus?

The somatosensory homunculus is a 'tiny body map' in the brain where larger, more sensitive areas take up more space.

How does the CNS distinguish between strong and weak stimuli?

A strong stimulus generates more frequent action potentials, while a weak stimulus generates fewer action potentials.

Describe the pathway for pain and temperature sensation to the somatosensory cortex.

1st neuron from receptor to spinal cord, 2nd neuron crosses to the opposite side of the spinal cord, 3rd neuron to the thalamus → somatosensory cortex.

What is a dermatome?

A dermatome is a skin area supplied by one spinal nerve used to check levels of spinal cord injury.

Explain referred pain with an example.

Referred pain is pain felt in a different area from where it originates, e.g., a heart attack causing pain in the left arm.

Where are olfactory receptors located and how are they activated?

Olfactory receptors are located in the top of the nasal cavity and are activated by odor molecules binding to receptors on olfactory cilia.

What are the five types of taste receptors?

1. Sweet, 2. Sour, 3. Salty, 4. Bitter, 5. Umami.

How are taste receptors activated?

Taste receptors are activated when chemicals from food dissolve in saliva and bind to taste receptor cells in taste buds.