Nervous System: Sensory Function & Physiology

A comprehensive set of flashcards covering key concepts from the lecture on sensory physiology and the nervous system function.

What is the primary focus of Chapter 1 in the lecture?

The sensory function of the nervous system.

What are the two additional graded potentials introduced in this lecture?

Generator potentials and receptor potentials.

What type of stimuli do Pacinian corpuscles detect?

They detect mechanical stimuli, such as deep pressure.

Where is the cell body of the first order sensory neuron located?

In the dorsal root ganglion.

What must be met for the trigger zone to fire an action potential?

The threshold potential.

What is the term for the potential generated by the distortion of a receptor?

Generator potential.

What is unique about receptor potentials compared to generator potentials?

Receptor potentials are initiated by specialized sensory receptors, while generator potentials arise from non-specialized sensory endings.

What is meant by the term 'label lines' in sensory pathways?

Label lines refers to the concept that different sensory modalities are transmitted via specific pathways to the brain.

What are the four general senses mentioned in the lecture?

Pain, temperature, pressure, and touch.

What is the functional name of the cortex responsible for perceiving sensory information?

Primary somatosensory cortex.

What is the anatomical name for the primary somatosensory cortex?

Post central gyrus.

Which neurons are classified as part of the central nervous system?

The second order neuron and third order neuron.

What does a sensory unit consist of?

One afferent neuron and all the receptors it innovates.

What is the definition of a receptive field?

The area from which a sensory neuron can receive input.

What is the effect of a larger receptive field on sensory perception?

It decreases the brain's ability to distinguish between two stimuli.

What is frequency coding in sensory perception?

The number of action potentials fired per unit time indicating stimulus intensity.

What is population coding?

The activation of multiple sensory neurons representing stimulus intensity.

How does the brain determine the location of a stimulus?

Through lateral inhibition and mapping of sensory input onto the cortex.

What concept allows the brain to distinguish the exact location of a noxious stimulus?

Lateral inhibition.

Name one example of a slowly adapting receptor.

Muscle stretch receptors.

What type of sensory receptors respond only at the onset and offset of stimuli?

Rapidly adapting or phasic receptors.

Which pathway conveys pain and temperature sensations?

Spinothalamic tract.

What is the difference in neural pathways for nociceptors and mechanoreceptors?

Nociceptors travel through the spinothalamic tract, while mechanoreceptors use the dorsal column medial lemniscal pathway.

What structure does pain perception travel through to reach the primary somatosensory cortex?

Thalamus.

What type of potential is generated when a stimulus exceeds a certain threshold?

Action potential.

What do free nerve endings primarily detect?

Pain and temperature.

What is the role of nociceptors?

To detect noxious stimuli leading to the perception of pain.

What is defined as visceral or referred pain?

Pain that originates from internal organs but is perceived in another area of the body.

What is the primary neurotransmitter released by first order sensory neurons?

Substance P.

What is the function of enkephalins in pain modulation?

To inhibit neurotransmitter release from first order neurons, reducing pain perception.

Which sensory modality has the largest area of the cerebral cortex dedicated to its processing?

Vision.

What happens to your ability to taste food if your sense of smell is compromised?

It decreases significantly; 80% of taste is dictated by smell.

Why is the sense of smell unique compared to other senses?

It directly connects to memory centers in the brain, bypassing the thalamus.

What is the primary role of the hypothalamus in temperature regulation?

It acts as a thermostat to regulate body temperature.

What is phototransduction?

The process of converting light into graded potentials in the retina.

What is the main neurotransmitter involved in the phototransduction process in darkness?

Cyclic GMP.

What initiates the phototransduction process when light strikes the retina?

Activation of rhodopsin and the subsequent breakdown of cyclic GMP.

In the absence of light, what is the state of photoreceptors?

They are depolarized and continuously releasing neurotransmitters.

What is the role of the ganglion cells in the retina?

They generate action potentials and transmit visual information to the brain.

What is the function of the superior colliculus in vision?

It is involved in visual reflexes.

What type of sensory neuron is involved in the response to pain?

C fibers.

In what kind of sensory processing do A-beta fibers participate?

They facilitate the inhibition of pain through touch sensation.

What is the relationship between stimulus strength and action potentials in frequency coding?

Stronger stimuli generate more action potentials.

What happens to the release of glycine when rubbing an injured area?

It increases, which decreases pain perception.

What are the five special senses?

Taste, smell, sight, hearing, and balance.

What do mechanoreceptors respond to?

Stretch and compression.

How does the body prioritize pain over other sensations?

Pain perception overrides other sensory modalities because it protects from injury.

What is the purpose of the endogenous analgesia system?

To inhibit pain signals in the spinal cord and brain.

What do the carotid and aortic bodies detect?

Chemical changes in the blood, specifically levels of oxygen and carbon dioxide.

What happens to cells during phototransduction when light hits them?

They hyperpolarize, leading to decreased neurotransmitter release.

What is the major function of the primary visual cortex?

To process visual information and enable visual perception.

What is the primary reason vision is considered the most important sense?

It occupies a significant portion of the cerebral cortex for processing visual stimuli.

How do sensory receptors transmit signals to the central nervous system?

Through graded potentials that, when above threshold, generate action potentials.

What leads to the conscious perception of a sensation?

Transmission of sensory signals to the primary somatosensory cortex.