Dr Gawad Physiology Course Online Exams – Sensory Receptors

1. All the following are important for coding of sensory information except:

Modality discrimination

Locality discrimination.

Cytoplasmic discrimination.

Strength discrimination

The coding of sensory information involves various processes, such as modality discrimination (differentiating between different sensory modalities), locality discrimination (determining the location of the sensory input), and strength discrimination (perceiving the intensity or magnitude of the sensory stimulus). However, cytoplasmic discrimination is not a recognized or relevant process in the coding of sensory information.

Explanation

The coding of sensory information involves various processes, such as modality discrimination (differentiating between different sensory modalities), locality discrimination (determining the location of the sensory input), and strength discrimination (perceiving the intensity or magnitude of the sensory stimulus). However, cytoplasmic discrimination is not a recognized or relevant process in the coding of sensory information.

2. Which of the following is a phasic adapting receptor:

Baroreceptor

Muscle spindles

Nociceptors

Touch receptors

Touch receptors are considered phasic adapting receptors because they rapidly adapt to a constant stimulus. When a stimulus is first applied, touch receptors respond strongly, but their response diminishes over time, allowing them to focus on detecting changes in the stimulus rather than maintaining a constant response. This adaptation allows us to quickly detect new or changing tactile sensations while filtering out continuous or unchanging stimuli.

Explanation

Touch receptors are considered phasic adapting receptors because they rapidly adapt to a constant stimulus. When a stimulus is first applied, touch receptors respond strongly, but their response diminishes over time, allowing them to focus on detecting changes in the stimulus rather than maintaining a constant response. This adaptation allows us to quickly detect new or changing tactile sensations while filtering out continuous or unchanging stimuli.

3. About receptor potential which of the following is true:

It obeys the all or none rule.

It is a form of a local un-propagated action potential.

Its absolute refractory period is too short.

It is blocked by local anesthetics.

The correct answer is that receptor potential is a form of a local un-propagated action potential. Receptor potential refers to the electrical signals generated by sensory receptors in response to a stimulus. Unlike action potentials, which can propagate along the length of a neuron, receptor potentials are localized and do not travel far. They are typically generated at the sensory receptor site and are responsible for initiating the transmission of sensory information to the central nervous system.

Explanation

The correct answer is that receptor potential is a form of a local un-propagated action potential. Receptor potential refers to the electrical signals generated by sensory receptors in response to a stimulus. Unlike action potentials, which can propagate along the length of a neuron, receptor potentials are localized and do not travel far. They are typically generated at the sensory receptor site and are responsible for initiating the transmission of sensory information to the central nervous system.

4. The law of projection means that:

Each receptor is specific to a single stimulus.

With increasing the intensity of the stimulus the receptor action potential amplitude increases.

With stimulation of a receptor, this sensation is referred to a specific location in the brain areas.

Increasing the number of the receptors stimulated leads to increasing number of nerve impulses.

The law of projection refers to the phenomenon where the brain localizes a sensation to a specific location based on the stimulation of a receptor. This means that when a receptor is stimulated, the brain is able to determine where the sensation is coming from and attribute it to a specific location in the brain areas. This allows us to perceive sensations in a spatially organized manner, providing us with a sense of location and directionality in our perception of stimuli.

Explanation

The law of projection refers to the phenomenon where the brain localizes a sensation to a specific location based on the stimulation of a receptor. This means that when a receptor is stimulated, the brain is able to determine where the sensation is coming from and attribute it to a specific location in the brain areas. This allows us to perceive sensations in a spatially organized manner, providing us with a sense of location and directionality in our perception of stimuli.

5. Which is false regarding receptor differential senstivity

Each receptor has its own most senstive stimulus called adequate stimulus

Any receptor will never be stimulated by any other form of stimulus rather tha its adequate stimulus

Low of projection is important and related to specificity

None of the above

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Explanation

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6. Redarding sensation intensity detection, which is true:

It depends on the frequency of receptor potential

It is inversly related to the stimulus strenght

It is directly proportional to receptor potential amplitude

None of the above

The correct answer is that sensation intensity detection is directly proportional to receptor potential amplitude. This means that as the amplitude of the receptor potential increases, the sensation intensity also increases. In other words, the stronger the receptor potential, the stronger the perception of the sensation. This relationship suggests that the magnitude of the receptor potential plays a crucial role in determining the intensity of the sensation experienced by an individual.

Explanation

The correct answer is that sensation intensity detection is directly proportional to receptor potential amplitude. This means that as the amplitude of the receptor potential increases, the sensation intensity also increases. In other words, the stronger the receptor potential, the stronger the perception of the sensation. This relationship suggests that the magnitude of the receptor potential plays a crucial role in determining the intensity of the sensation experienced by an individual.