Sensory Physiology Overview

The modalities of sensation include chemical, thermal, light, mechanical, nociceptive, and proprioceptive sensations.

The main types of sensory receptors are chemoreceptors, thermoreceptors, photoreceptors, mechanoreceptors, nociceptors, and proprioceptors.

A receptive field is the specific area of skin that, when stimulated, causes a response in a sensory neuron.

<p>The Two-Point Discrimination Test assesses the ability to perceive two separate points of contact on the skin, indicating the density of sensory receptors in a given area.</p> Signup and view all the answers

<p>Generator potentials are created when sensory receptors transduce stimuli into electrical signals, leading to depolarization in response to adequate stimulus strength.</p> Signup and view all the answers

<p>Action potentials in sensory neurons are initiated when the generator potential reaches a threshold level, resulting in the rapid depolarization of the neuron's membrane.</p> Signup and view all the answers

<p>Sensory information is transmitted from sensory neurons to the sensory cortex via specific neural pathways, where it is interpreted and perceived.</p> Signup and view all the answers

<p>Rapidly adapting receptors decrease their discharge rate when a constant stimulus is applied, while slowly adapting receptors continue to respond as long as the stimulus persists.</p> Signup and view all the answers

<p>Nociceptors are responsible for detecting noxious stimuli that can cause pain, serving a protective function by alerting the body to potential harm.</p> Signup and view all the answers

<p>Proprioception refers to the awareness of body part positions and movements, playing a critical role in spatial orientation and coordination.</p> Signup and view all the answers

<p>Photoreceptors transduce light energy into electrical signals.</p> Signup and view all the answers

<p>Discriminative touch is the sensation that includes light touch, precise location identification (two-point discrimination), and stereognosis.</p> Signup and view all the answers

<p>The spinothalamic tract transmits sensory information related to pain, temperature, crude touch, itch, and tickle via a three-neuron relay system.</p> Signup and view all the answers

<p>The sensory homunculus represents the distribution of sensory receptors across the body, indicating that cortex area allocation is based on receptor density rather than physical size.</p> Signup and view all the answers

<p>Third-order axons relay sensory information from the thalamus to specific areas of the somatosensory cortex, enabling precise perception of sensations.</p> Signup and view all the answers

<p>It transmits sensations of pain, temperature, crude touch, itch, and tickle.</p> Signup and view all the answers

<p>The somatosensory cortex is located in the parietal lobe and is responsible for the conscious perception of incoming sensory information.</p> Signup and view all the answers

<p>The sensory cortex is organized according to a sensory homunculus, where various areas correspond to the density of sensory receptors in different body parts.</p> Signup and view all the answers

<p>Stereognosis is the ability to recognize objects through touch alone, relying on discriminative touch for detailed sensory feedback.</p> Signup and view all the answers

<p>Conscious perception of sensations occurs when sensory information reaches the somatosensory cortex for analysis and interpretation.</p> Signup and view all the answers

<p>Receptive field size varies inversely with the number of receptors; smaller receptive fields are found in areas with a higher density of receptors.</p> Signup and view all the answers

<p>Generator potentials are local graded changes in membrane potential; when they reach a threshold, they result in action potentials.</p> Signup and view all the answers

<p>The thalamus serves as an important relay center for sensory information on its way to the sensory cortex.</p> Signup and view all the answers

<p>Sensory information travels from receptors to first order neurons, then synapses in the medulla, proceeds through the thalamus, and finally reaches the somatosensory cortex.</p> Signup and view all the answers

<p>The medial lemniscal tract carries information about fine touch and proprioception, while the spinothalamic tract transmits pain and temperature sensations.</p> Signup and view all the answers

<p>Dorsal columns carry sensory information from skin, muscles, tendons, and joints regarding touch, pressure, and proprioception.</p> Signup and view all the answers

<p>The two main dorsal column nuclei are the nucleus gracilis and the nucleus cuneatus.</p> Signup and view all the answers

<p>Two-point discrimination is a measure of tactile acuity that depends on small receptive fields found in areas with a high density of cutaneous receptors.</p> Signup and view all the answers

<p>Sensory neurons synapse on third order neurons in the thalamus before sending information to the somatosensory cortex.</p> Signup and view all the answers

<p>The trigeminal nerve (Cranial Nerve V) is responsible for the sensory innervation of the face via its sensory fibers.</p> Signup and view all the answers