Anatomy and Physiology: Sensory Perception, Central Processing, and Motor Responses

Vocabulary flashcards covering key terms and definitions for sensory perception, central processing pathways, and motor responses from chapter review materials.

Alkaloid

Substance, usually from a plant source, that is chemically basic with respect to pH and will stimulate bitter receptors.

Amacrine cell

Type of cell in the retina that connects to the bipolar cells near the outer synaptic layer and provides the basis for early image processing within the retina.

Ampulla

In the ear, the structure at the base of a semicircular canal that contains the hair cells and cupula for transduction of rotational movement of the head.

Anosmia

Loss of the sense of smell; usually the result of physical disruption of the first cranial nerve.

Anterior corticospinal tract

Division of the corticospinal pathway that travels through the ventral (anterior) column of the spinal cord and controls axial musculature through the medial motor neurons in the ventral (anterior) horn.

Aqueous humor

Watery fluid that fills the anterior chamber containing the cornea, iris, ciliary body, and lens of the eye.

Ascending pathway

Fiber structure that relays sensory information from the periphery through the spinal cord and brain stem to other structures of the brain.

Association area

Region of cortex connected to a primary sensory cortical area that further processes the information to generate more complex sensory perceptions.

Basilar membrane

In the ear, the floor of the cochlear duct on which the organ of Corti sits.

Betz cells

Output cells of the primary motor cortex that cause musculature to move through synapses on cranial and spinal motor neurons.

Binocular depth cues

Indications of the distance of visual stimuli on the basis of slight differences in the images projected onto either retina.

Bipolar cell

Cell type in the retina that connects the photoreceptors to the RGCs.

Broca's area

Region of the frontal lobe associated with the motor commands necessary for speech production.

Capsaicin

Molecule that activates nociceptors by interacting with a temperature-sensitive ion channel and is the basis for 'hot' sensations in spicy food.

Chemoreceptor

Sensory receptor cell that is sensitive to chemical stimuli, such as in taste, smell, or pain.

Cochlea

Auditory portion of the inner ear containing structures to transduce sound stimuli.

Cone photoreceptor

One of the two types of retinal receptor cell that is specialized for color vision through the use of three photopigments distributed through three separate populations of cells.

Cornea

Fibrous covering of the anterior region of the eye that is transparent so that light can pass through it.

Decussate

To cross the midline, as in fibers that project from one side of the body to the other.

Dorsal column system

Ascending tract of the spinal cord associated with fine touch and proprioceptive sensations.

Dorsal stream

Connections between cortical areas from the occipital to parietal lobes that are responsible for the perception of visual motion and guiding movement of the body in relation to that motion.

Encapsulated ending

Configuration of a sensory receptor neuron with dendrites surrounded by specialized structures to aid in transduction of a particular type of sensation, such as the lamellated corpuscles in the deep dermis and subcutaneous tissue.

Fovea

Exact center of the retina at which visual stimuli are focused for maximal acuity, where the retina is thinnest, at which there is nothing but photoreceptors.

Gustation

Sense of taste.

Interaural intensity difference

Cue used to aid sound localization in the horizontal plane that compares the relative loudness of sounds at the two ears, because the ear closer to the sound source will hear a slightly more intense sound.

Interaural time difference

Cue used to help with sound localization in the horizontal plane that compares the relative time of arrival of sounds at the two ears, because the ear closer to the sound source will receive the stimulus microseconds before the other ear.

Lateral corticospinal tract

Division of the corticospinal pathway that travels through the lateral column of the spinal cord and controls appendicular musculature through the lateral motor neurons in the ventral (anterior) horn.

Macula

Enlargement at the base of a semicircular canal at which transduction of equilibrium stimuli takes place within the ampulla.

Nociceptor

Receptor cell that senses pain stimuli.

Olfaction

Sense of smell.

Optic chiasm

Decussation point in the visual system at which medial retina fibers cross to the other side of the brain.

Organ of Corti

Structure in the cochlea in which hair cells transduce movements from sound waves into electrochemical signals.

Photoisomerization

Chemical change in the retinal molecule that alters the bonding so that it switches from the 11-cis-retinal isomer to the all-trans-retinal isomer.

Proprioception

Sense of position and movement of the body.

Rod photoreceptor

One of the two types of retinal receptor cell that is specialized for low-light vision.

Sensory homunculus

Topographic representation of the body within the somatosensory cortex demonstrating the correspondence between neurons processing stimuli and sensitivity.

Spinothalamic tract

Ascending tract of the spinal cord associated with pain and temperature sensations.

Suprachiasmatic nucleus

Hypothalamic target of the retina that helps to establish the circadian rhythm of the body on the basis of the presence or absence of daylight.

Transduction

Process of changing an environmental stimulus into the electrochemical signals of the nervous system.

Umami

Taste submodality for sensitivity to the concentration of amino acids; also called the savory sense.

Ventral stream

Connections between cortical areas from the occipital lobe to the temporal lobe that are responsible for identification of visual stimuli.

Vestibulo-ocular reflex (VOR)

Reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures images are stabilized on the retina as the head and body move.