How is sensation different from perception ?
Sensation: detection of a stimulus (a change) in the environment.
This may or many not include conscious awareness of the stimulus.
Perception: Being conscious of a stimulus, able to interpret the sensation.
What is a sensory modality?
Sensory modality is a specific type of sensation (touch, smell, etc)
How are generator potentials and receptor potentials similar?How are
they different?
Generator potential is a graded potential, which, if strong enough,
will trigger a nerve impulse in a first order sensory neuron. Receptor
potential also leads to nerve impulse. This is a graded potential as
well, which causes a neurotransmitter release, leading to an EPSP or
IPSP in a first order sensory neuron.
What is the difference between rapidly adapting and slowly adapting receptors?
Rapidly adapting signals a change in a stimulus, slowly adapting
triggers and remains for as long as the stimulus persists.
Which somatic sensory receptors are encapsulated?
Touch, pressure, vibration
Why do some receptors adapt slowly and others adapt rapidly?
Fast adapting alerts you if there is a change in the stimulus, like
the onset of touch. They are more sensitive to small changes because
they fire rapidly. Slow adapting fire slower, and are usually involved
in static perception (e.g. holding an object).
Which somatic sensory receptors mediate touch sensations?
Meissner's corpuscles, hair root plexus, Merkel disc, Ruffini corpuscles.
Stimulation of receptors in skeletal muscles, joints, tendons, and
fascia causes;
Deep Somatic Pain
Pain that arises from stimulation of receptors in the skin is called;
Superficial Somatic Pain
Nociceptors are found in every tissue of the body except:
the brain
What are Muscle spindles?
Proprioceptors in skeletal
What is the awareness of body position?
Proprioception
What is referred pain ?
Visceral pain that is felt at a site remote from its origin, such as
in an area of skin that is far away from the affected visceral organ.
How does fast pain differ from slow pain?
Fast pain is perceived 0.1 seconds after the stimulus, it is sharp,
acute pain. Slow pain is perceived 1 second or more after the stimulus
and tends to be chronic, throbbing pain.
What type of stimuli activates nociceptors?
Intense thermal, mechanical,or chemical stimuli
What aspects of the muscle function are monitoring by muscle spindles
and tendon organs ?
Stretch and tension in the muscle.
How is a muscle spindle activated?
When the central area of the intrafusal fibers is stretched.
When a muscle contracts it exerts a force that pulls the points of
attachment of the muscle at either end toward each other. What is this
force called?
Muscle Tension
What is ischemia?
inadequate blood flow to an organ
What type of pain is acute, sharp, or prickling ? And is not felt in
deeper tissues of the body ?
Fast pain
The Anterolateral Pathway is also know as:
The Spinolateral Tract
Each muscle spindle consists of several slowly adapting sensory nerve
endings that wrap around 3 to 10 specialized muscle fibers. A
connective tissue capsule encloses the sensory nerve endings and
anchors the spindle to________ & _____________.
The endomysium and perimysium
Which pathway conveys nerve impulses for pain, warmth, itch, tickle,
and posterior head to the cerebral cortex?
The Anterolateral Pathway
What are the two major tracts that form the posterior columns ?
Gracile faciculus and cuneate fasciculus
Where do first neurons conduct impulses ?
from the somatic receptors into the brain stem or spinal cord.
What pathway relays information from the somatic sensory receptor to
the primary somatosensory area in the cerebral cortex and to the cerebellum?
Somatic sensory pathway
Which cranial nerve conveys impulses for most somatic sensations from
the left side of the face into the pons ?
The left trigeminal nerve V conveys nerve impulses from the left side
of the face to into the pons.
What are the functional differences between the posterior column -
medial lemniscus pathway, the anterolateral pathway, and the
trigeminothalamic pathway ?
Medial lemniscus pathway: touch, pressure, vibration, conscious
proprioception in body, neck and back of head. Anterolateral pathway:
pain, cold, heat, itch, tickle, throughout body. Trigeminothalamic
pathway: tactile, thermal, pain, proprioception in face/head.
What type of sensory information is carried in the spinocerebellar
tracts, and what is its function?
proprioception. Helps to maintain balance, motor coordination, balance.
Which body parts have the largest representation in the primary
somatosensory area ?
Face, tongue, lips, fingertips/hands.
How do the functions of upper motor neurons from the cerebral cortex
and from the brain stem differ?
Cerebral cortex Upper motor neurons are essential for the execution
of voluntatry movements of the body. Brain stem UMN regulate muscle
tone, comtrol posture
Name the pathway ; touch,pressure, vibration, and conscious
proprioception from limbs, trunk, neck, and posterior head to
the cerebral cortex.
Posterior column-medial lemniscus pathway
What are the two major tracts that are located in the spinal cord
that carries proprioceptive impulses to the cerebellum.
Anterior and Posterior Spinocerebellar Tracts
Name the pathway; pain, cold,
warmth, itch, and tickle from limbs, trunk, neck, and
posterior head to the cerebral cortex.
Anterolateral (spinothalamic) pathway
Name the pathway; touch, temperature, pain,
and proprioception from face, nasal cavity, oral cavity, and teeth
to cerebral cortex.
teeth to cerebral cortex.
Trigeminothalamic pathway =
What are the three pathways that are somatic sensory pathways?
Anterolateral, Trigeminothalamic, Posterior- medial lemniscus Pathways.
Neurons from __________ and cerebellum help regulate the activity of
upper motor neurons.
the basal nuclei
Because only the lower motor neurons transmit output from the CNS to
skeletal muscles, they are referred to as
The final common pathway
________ motor neurons have their cell bodies in the brain stem and
spinal cord and their axons are in the cranial and spinal nerves.
Lower Motor Neurons
________ motor neurons in the cerebral cortex or brain stem connect
directly or, more often, indirectly (via interneurons called local
circuit neurons) with lower motor neurons that innervate skeletal muscles.
Upper Motor Neurons
The direct (voluntary) motor pathways that control muscles of the
limbs and trunk:
The lateral and anterior corticospinal, cortico-bulbar pathways
The pathway controls the distal muscles responsible for precise,
skilled movements. Axons decussate in the medulla (pyramidal decussation).
Lateral pathway