Chapter 17 Flashcards
How does the CNS communicate with the body?
Via pathways
Pathways travel through what matter?
White
What does the pathways consist of?
A tract and a Nucleus
What does each tract work with?
multiple nuclei groups in the CNS
What is a nucleus?
collection of neuron cell bodies within the CNS
What is Ascending pathways?
carry sensory information from the peripheral body to the brain
What is Descending Pathways?
transmit motor information from the brain or brainstem to muscles or glands
somatotopy
Pathways that connect the primary motor cortex to a specific body part exhibit somatotopy.
All pathways are composed of….
paired tracts
A pathway on the left side of the CNS has a matching tract on the….
right side of the CNS
What does Sensory Pathways have?
have primary neurons, secondary neurons, and sometimes tertiary neurons that facilitate the pathway’s functioning
What does a Motor Pathway have?
upper motor neuron and a lower motor neuron
Somatosensory pathways
process stimuli received from receptors within the skin, muscles, and joints
Viscerosensory pathways
process stimuli received from the viscera
What do Sensory receptors detect?
stimuli and then conduct nerve impulses to the CNS
What do sensory pathways within the spinal cord and brain stem do?
process and filter the incoming sensory information
Sensory Pathways determine whether the sensory stimulus should be transmitted to the…..
cerebrum or terminated
What percent of incoming impulses do not reach the cerebral cortex and our conscious awareness?
more than 99%
How many pathways does the sensory use to transmit stimulus information from the body periphery to the brain?
two or three neurons
What neuron is the primary?
First neuron
Where do the cell bodies reside? (1st neuron)
in the posterior root ganglia of spinal nerves or the sensory ganglia of cranial nerves
Where is does the axon of the primary neuron project to?
projects to a secondary neuron within the CNS
The secondary neuron is a….
interneuron
Where do the cell bodies reside? ( 2nd neuron)
within either the posterior horn of the spinal cord or a brainstem nucleus
The tertiary neuron is also an….
interneuron
Where do the cell bodies reside? ( 3rd neuron)
within the thalamus
What is Funiculus cuneatus and gracilis do?
Conduct sensory impulses for information about limb position and discriminative touch, precise pressure, and vibration sensation
What is Located in the anterior and lateral white funiculi of the spinal cord?
anterior spinothalamic tract
lateral spinothalamic tract
Anterior spinothalamic tract conduct…
sensory impulses for crude touch and pressure
Lateral spinothalamic tract conduct…
sensory impulses for pain and temperature
What does Spinocerebellar Pathway conduct?
proprioceptive information to the cerebellum for processing to coordinate body movements
the spinocerebellar is composed of..
anterior and posterior spinocerebellar tracts
Spinocerebellar do NOT use
tertiary (3rd) neurons
Anterior spinocerebellar tract conduct….
proprioceptive impulses from inferior regions of trunk and lower limbs
Posterior spinocerebellar tract conduct….
proprioceptive impulses from lower limbs, regions of trunk and upper limbs
Direct Pathways include
Corticobulbar, anterior and posterior corticospinal tracts.
Indirect Pathways include
Rubrospinal tract, Reticulospinal tract, Tectospinal tract and the Vestibulospinal tract
Where do Corticobulbar Tracts originate from?
the facial region of the motor homunculus within the primary motor cortex
Corticobulbar control…
eye movements (via CN III, IV, and VI)
cranial, facial, pharyngeal, and laryngeal muscles (via CN V, VII, IX, and X)
some superficial muscles of the back and neck (via CN XI)
intrinsic and extrinsic tongue muscles (via CN XII)
How are pyramids form?
Descend from the cerebral cortex through the brainstem and form a pair of thick bulges in the medulla
The pyramids continue into….
the spinal cord to synapse on lower motor neurons in the anterior horn of the spinal cord
Lateral corticospinal tract:
Voluntary movement of limb muscles
Anterior corticospinal tract:
Voluntary movement of axial muscles
What do Axon take?
a complex, circuitous route before finally conducting the motor impulse into the spinal cord
Rubrospinal tract (Lateral pathway) regulates
Regulates and controls precise, discrete movements and tone in flexor muscles of the limbs
Reticulospinal tract ( Medial pathway) controls
Controls more unskilled automatic movements related to posture and maintaining balance
Tectospinal tract (Medial Pathway) regulates
Regulates positional changes of the upper limbs, eyes, head, and neck due to visual and auditory stimuli
Vestibulospinal tract (Medial Pathway) regulates
Regulates muscular activity that helps maintain balance during sitting, standing, and walking
What does the cerebral nuclei do?
Receive impulses from the entire cerebral cortex
Most of the output of the cerebral nuclei goes to…
the primary motor cortex.
The cerebral nuclei provides….
the patterned background movements needed for conscious motor activities
When are movements initiated?
when commands are received by the primary motor cortex from the motor association areas
The cerebral cortex controls…
Controls highly variable and complex voluntary motor patterns
The cerebral cortex occupies the highest level of
processing and motor control
Higher-order mental functions are…
consciousness, learning, memory, and reasoning
Where does the left hemisphere function?
in categorization and symbolization. ( science and math)
Cerebral Lateralization is the….
speech-dominant hemisphere
Right hemisphere is called the…
representational hemisphere (the seat of imagination)
