CHAPTER 16 Sensory, Motor, and Integrative Systems Flashcards
What is the definition of sensation?
is the conscious or subconscious
awareness of changes in the external or internal environment.
What is perception?
is the conscious interpretation of sensations and is primarily a function of the cerebral cortex
Each unique type of sensation such as touch, pain, vision, or hearing is called?
Sensory Modailty
The nature of a sensation and the type of reaction generated vary according to ___________________
the destination of sensory impulses in the CNS.
How many sensory modalities does a sensory neuron serve?
only 1
What 4 events need to occur for a sensation to arise?
stimulation
transduction
generation of impulses
integration.
What type of receptors consist of free nerve endings and encapsulated nerve endings, are associated with the general senses
Simple receptors
What types of receptors are associated with the special senses?
Complex receptors
Sensory receptors respond to stimuli by producing _______________
receptor potentials
Another way to group sensory receptors is based on the location of the receptors and the origin of the stimuli that activate them. What are the three locations?
Exteroceptors
Interoceptors
Proprioceptors
Where are Exteroceptors located and what stimulates them?
They are located at or near the external surface of the body
They are sensitive to stimuli originating outside the body and pro- vide information about the external environment.
Where are Interoceptors located and what activates them?
-located in blood vessels, visceral organs, muscles, and the nervous system and monitor conditions in the internal environment
- not consciously perceived
Where are Proprioceptors located and their function?
Located in muscles, tendons, and joints
They provide information about where your body is in space (balance)
What are the 6 types of receptors for stimulation detection?
Mechanoreceptors
Thermoreceptors
Nociceptors
Photoreceptors
Chemoreceptors
Osmoreceptors
What do Mechanoreceptors detect?
mechanical stimulation of the body
What do Thermoreceptors detect?
Changes in tempurature
What do Nociceptors detect?
Painful stimuli resulting from physical or chemical damage to tissue
What do Photoreceptors detect?
the light that strikes the retina of the eye
What do Chemoreceptors detect?
chemicals in the mouth (taste), nose (smell), and body fluids.
What do Osmoreceptors detect?
Osmotic pressure of body fluids
A characteristic of most sensory receptors is their ability to adapt what are the two types of adapting receptors?
Rapidly adapting receptors
Slowly adapting receptors
_________ are sensations that arise from stimulation of sensory receptors embedded in the skin or subcutaneous tissue; in mucous membranes of the mouth, vagina, and anus; and in skeletal muscles, tendons, and joints.
Somatic sensations
Somatic sensations that arise from stimulating the skin surface are called _____________
cutaneous sensations
The________ sensations include touch, pressure, vibration, itch, and tickle
tactile
What are the 5 tactile sensations?
touch, pressure, vibration, itch, and tickle
Sensations of _______ generally result from stimulation of tactile receptors in the skin or subcutaneous layer
touch
What are touch receptors that are located in the dermal papillae of skin and hair called?
Corpuscles of touch
What are the two types of slow-adapting touch receptors?
Type I cutaneous mechanoreceptors
Type II cutaneous mechanoreceptors
What are Type I cutaneous mechanoreceptors? AKA tactile discs
are saucer-shaped, flattened free nerve endings that make contact with tactile epithelial cells of the stratum basale
What are Type II cutaneous mechanoreceptors?
are elongated, encapsulated receptors located in the dermis, subcutaneous layer, and other tissues of the body
What is pressure?
a sustained sensation that is felt over a larger
area than touch, occurs with deeper deformation of the skin and subcutaneous layer
What is vibration?
Vibration results from rapidly repetitive
sensory signals from tactile receptors
what is a lamellated corpuscle
nerve ending surrounded by a multilayered connective tissue capsule
What causes the itch sensation?
The itch sensation results from the stimulation of the free nerve endings by certain chemicals
What are thermoreceptors?
Free nerve endings that have receptive fields
about 1 mm in diameter on the skin surface.
Where are cold receptors located?
they are located in the stratum basale of the epidermis
What temperatures activate cold receptors?
Temperatures between 10° and 35°
Where are warm receptors located?
Located in the dermis
What temperatures activate warm receptors?
Temperatures between 30° and 45°
What are nociceptors?
the receptors for pain, are free nerve endings found
in every tissue of the body except the brain
What activates the nociceptors?
Intense thermal, mechanical, or chemical stimuli
What are the two types of pain?
Fast and Slow pain
What is fast pain?
Fast pain occurs very rapidly, usually within 0.1 seconds after a stimulus is applied because the nerve impulses propagate along medium-diameter
What is slow pain?
begins a second or more after a stimulus is applied. It then gradually increases in intensity over a period of several seconds or minutes.
Pain that arises from stimulation of receptors in the skin is called ___________
superficial somatic pain
Pain that arises from stimulation of receptors in skeletal muscles, joints, tendons, and fascia are called ___________
deep somatic pain
What type of pain results from the stimulation of nociceptors in organs?
Visceral pain
____________________is very precisely localized to
the stimulated area
Fast pain
______________ is well localized but more diffuse, as
it usually appears to come from a larger area of the skin
Somatic slow pain
Visceral pain can be felt in or just deep to the skin that overlies the stimulated organ, or in a surface area far from the stimulated organ. What is this called?
Referred pain
What is kinesthsia?
is the perception of body movements.
Proprioceptors also allow weight discrimination, what does this mean?
the ability to assess the weight of an object
__________ are the proprioceptors that
monitor changes in the length of skeletal muscles and participate in stretch reflexes
Muscle spindles
What are intrafusal fibres?
a specialized cell population in skeletal muscle that is responsible for proprioceptive function
Near the middle of intrafusal fibres, muscle spindles contain motor neurons called___________
gamma motor neurons
Surrounding muscle spindles are ordinary skeletal muscle fibres, called _________
extrafusal muscle fibers
___________ are slowly adapting receptors located at the junction of a tendon and a muscles
tendon organs
Several types of joint kinesthetic receptors are present within and around the ___________ _________ of synovial joints.
articular capsules
Somatic sensory pathways relay information
from what type of sensory receptors to the primary somatosensory area?
somatic sensory receptors
Where is the primary somatosensory cortex area located?
in the parietal lobe of the cerebrum and to the cerebellum
A somatic sensory pathway consists of thousands of sets of three neurons:
a first-order neuron
a second-order neuron
a third-order neuron.
What are the first-order neurons?
are sensory neurons that conduct nerve impulses from somatic sensory receptors into the brainstem or spinal cord
What are second-order neurons?
conduct nerve impulses from the brainstem or spinal cord to the thalamus
Axons of second-order neurons _____________ as they course through the brainstem or spinal cord before ascending to the thalamus.
decussate (cross over to the opposite side)
What are third-order neurons?
conduct nerve impulses from the thalamus to the primary somatosensory cortex on the same side.
Regions within the CNS where neurons synapse with other neurons that are a part of a particular sensory or motor pathway are known as _______ ____
Relay stations
Particular sensory or motor pathways are known as relay stations because?
neural signals are being relayed from one region of the CNS to another
Somatic sensory impulses ascend to the cerebral cortex via three general pathways:
(1) the posterior column–medial lemniscus pathway
(2) the anterolateral (spinothalamic) pathway
(3) the trigeminothalamic pathway.
The posterior column medial—lemniscus pathway conveys nerve impulses for?
touch, pressure, vibration, and proprioception to the cerebral cortex
Where does the posterior column medial—lemniscus pathway convey information to?
the cerebral cortex
After entering the spinal cord, axons of these first-order neurons ascend to the medulla via tracts known as the _____ ________
posterior columns
Axons of the second-order neurons cross to the opposite side of the medulla and enter the __________ ___________
medial lemniscus
What is medial lemniscus?
a thin ribbonlike projection tract that extends from the medulla to the thalamus
The __________pathway conveys nerve impulses for pain, temperature, touch and pressure to the cerebral cortex
anterolateral (spinothalamic)
The anterolateral pathway conveys nerve impulses for pain, temperature, touch and pressure to where?
cerebral cortex
What is the trigeminothalamic pathway?
Nerve impulses for pain, temperature, touch, and proprioception from the face, nasal cavity, oral cavity, and teeth ascend to the cerebral cortex along
Nerve impulses for pain, temperature, touch, and proprioception from the face, nasal cavity, oral cavity, and teeth ascend to the _______ ______
cerebral cortex
The trigeminothalamic pathway sends signals to the ______
Pons
The trigeminothalamic pathway sends signals from the pons to what nerve?
the trigeminal (V) nerves
The axons of the second-order neurons cross
to the opposite side of the pons and medulla and then ascend as the _________ tract
trigeminothalamic tract
Precise localization of somatic sensations occurs when nerve impulses arrive at the?
primary somatosensory cortex
The primary somatosensory cortex occupies the?
postcentral gyri of the parietal lobes of the cerebral cortex.
Two tracts in the spinal cord are the major routes proprioceptive nerve impulses take to reach the cerebellum. What are the two tracts?
the anterior spinocerebellar tract
the posterior spinocerebellar tract
What are lower motor neurons?
responsible for transmitting the signal from the upper motor neuron to the effector muscle to perform a movement.
Nerve cells that only participate in the local aspects of a circuit are called __________ ________ neurons
local circuit
Local circuit neurons receive input from what type of receptor?
somatic sensory
What are upper motor neurons?
The nerves in the CNS which carry the impulses for movement
What are corpus striatum neurons?
neurons that assist in movement by input to upper motor neurons
A prime function of the ________ is to monitor differences between intended movements and movements actually performed.
cerebellum
Neural circuits interconnect the corpus striatum nuclei with motor areas of the _________ ____________ and the brain stem
cerebral cortex
What do cerebellar neurons do?
aid movement by controlling the activity of upper motor neurons.
What is the premotor cortex?
A crucial part of the brain, which is believed to have direct control over the movements of voluntary muscles.
What is the premotor cortex?
A crucial part of the brain, is believed to have direct control over the movements of voluntary muscles.
What is the primary motor cortex?
is the major control region for the execution of voluntary movements.
The primary motor cortex controls muscles by forming _______ pathways that extend to the spinal cord and brainstem
descending
The axons of upper motor neurons extend from the brain to lower motor neurons via two types of pathways what are they called?
Direct and indirect
What is a direct motor pathway?
They provide input to lower motor neurons via axons that extend directly from the primary motor cortex
What is an indirect motor pathway?
provide input to lower motor neurons from motor centers in the brainstem
Direct and indirect pathways both govern the generation of nerve impulses in the lower motor neurons, the neurons that stimulate the contraction of what type of muscle?
Skeletal
Nerve impulses for voluntary movements propagate from the primary motor cortex to lower motor neurons via the DIRECTor INDIRECT motor pathways
Direct
What is another name for the direct motor pathway?
Pyramidal pathway
Why is the pyramidal pathway called its name?
Because direct motor pathways consist of axons that descend from pyramidal cells
What are pyramidal cells?
Are upper motor neurons that have pyramid-shaped cell bodies
What is the purpose of pyramidal cells?
They are the main output cells of the cerebral cortex.
The direct motor pathways consist of twp pathways what are they?
corticospinal pathways
corticobulbar pathway
what is the corticospinal pathway?
conduct impulses for the control of muscles of the limbs and trunk
Axons of upper motor neurons in the primary motor cortex form the _________ tracts
corticospinal
What is the corticospinal tract?
a tract which descends through the internal capsule of the cerebrum and the cerebral peduncle of the midbrain
what are the two types of corticospinal tracts?
lateral corticospinal tract
the anterior corticospinal tract.
what is the Lateral corticospinal tract function?
The primary responsibility of the lateral corticospinal tract is to control the voluntary movement of contralateral limbs
What is the anterior corticospinal tract?
a small bundle of descending fibres that connect the cerebral cortex to the spinal cord.
What is the corticobulbar pathway?
A pathway that conducts impulses for the control of skeletal muscles in the head
Axons of upper motor neurons from the cerebral cortex form the ________ tract. Associated with the movement of the face
corticobulbar
The lower motor neurons of the cranial nerves convey impulses that control what type of movement?
precise and voluntary movements of the face
The brainstem contains four major motor centers that help regulate body movements what are they?
(1) the vestibular nuclei in the medulla and pon(2) the reticular formation located throughout the brainstem
(3) the superior colliculus in the midbrain
(4) the red nucleus
The brainstem motor centers give rise to the indirect motor pathways, also known as __________ ____________
extrapyramidal pathways
What does the indirect motor pathway include?
all somatic motor tracts other than the corticospinal and corticobulbar tracts
Axons of upper motor neurons descend from the brainstem motor centers into five major tracts of the spinal cord what are they?
Rubrospinal
Tectospinal
Vestibulospinal
Lateral reticulospinal
medial reticulospinal tracts
In general, the indirect motor pathways convey nerve impulses from the brainstem to cause
involuntary movements
Where are the vestibular nuclei located?
located in the medulla and pons of the hindbrain
What is the postural reflexes?
keep the body in an upright and balanced position.
What does the vestibulospinal tract do?
Conveys signals to the skeletal muscles of the trunk and proximal parts of the limbs
The vestibulospinal tract causes ________ of __________ in order to maintain posture in response to changes in equilibrium.
contraction of muscles
The reticular formation also helps control posture. TRUE or FALSE
True
discrete nuclei in the reticular formation generate action potentials along what two reticulospinal tracts?
medial reticulospinal tract
lateral reticulospinal tract
The _______ _________ receives visual input from the eyes and auditory input from the ears
superior colliculus
What is the tectospinal tract?
It is involved in orienting the eyes and the head toward sounds as part of the auditory and visual reflex
What is saccades?
a rapid movement of the eye between fixation points.
What is the rubrospinal tract function?
The rubrospinal tract mainly transmits signals into the red nucleus from the motor cortex and cerebellum to the spinal cord
What are the 4 functions of the corpus striatum?
Initiation of movements
Suppression of unwanted movement
Regulation of muscle tone
Regulation of nonmotor processes
The cerebellar function involves what four activities?
Monitoring intentions for movement
Monitoring actual movements
Comparing command signals with sensory information
Sending our corrective feedback
What is integration?
The processing of sensory information by analyzing and storing it and making decisions for various responses
What are the integrative functions of the cerebrum?
include cerebral activities such as wakefulness and sleep, learning and memory, and language.
The cerebral cortex contains two language areas what are they called?
Wernicke’s area
Broca’s area
What is Wenicke’s area responsible for in language?
It is responsible for the ability to comprehend spoken language
What is Broca’s area responsible for in language?
Speech production
