CNS Lecture 1B Flashcards
What is the Afferent division of the PNS?
Sensory inputs conveyed to CNS by sensory (afferent) nerve axons of the PNS
What is the Efferent division of the PNS?
Motor commands conveyed from CNS to the muscles and glands by motor efferent axons
The Afferent division of the PNS has what three divisions?
- Somatic sensory
- Visceral sensory
- Special sensory
The efferent division of the PNS can be subdivided into the ________ and the ________
Somatic motor and Autonomic Motor
The somatic motor division of the PNS controls ______
The autonomic motor division controls ______ (heart, gut, bladder etc)
The somatic division of the PNS controls voluntary movement (skeletal muscle)
The autonomic motor division controls involuntary movement (heart, gut, bladder etc)
The autonomic subdivision of the PNS can be further divided into the _______, _______ and the ______ divisions
The autonomic subdivision of the PNS can be further divided into the parasympathetic, sympathetic and the enteric divisions
Where is the cell body of a sensory axon of the PNS located?
Just outside the spinal cord in the posterior (dorsal) root ganglion
The axon of the afferent (sensory) neuron enters the spinal cord where it terminates on synaptic connections on _____\_ and ______
The axon of the afferent (sensory) neuron enters the spinal cord where it terminates on synaptic connections on interneurons and efferent neurons
The axons of efferent (motor) neurons synapse on effector organs: ______, ______, or _____
The axons of efferent (motor) neurons synapse on effector organs: muscles, glands, or other neurons
In general terms, the autonomic nervous system innervates _____, ______, and _____
In general terms, the autonomic nervous system innervates smooth muscle, cardiac muscle, and glands
The PNS transmits _______ information from the CNS to _______
The PNS transmits motor information from the CNS to effector organs and tissues
What neurotransmitters is released by efferent (motor) neurons onto skeletal muscle fibres causing contraction?
Acetylcholine
Parasympathetic and sympathetic divisions differ not only in their anatomy but in the _______ used and the _____ they bind to
Parasympathetic and sympathetic divisions differ not only in their anatomy but in the neurotransmitters used and the receptors they (the neurotransmitters) bind to
The _______ nervous system is a two-neuron chain while the ______ nervous system has only one neuron that transmits the signal from the CNS to the Effector organ
The AUTONOMIC nervous system is a two-neuron chain while the SOMATIC nervous system has only one neuron that transmits the signal from the CNS to the Effector organ
Two Neuron Pathway (autonomic NS)
The cell body of the first neuron (called the ________ neuron) is found within the _____ and it’s axon terminates in a ______ (cluster of cell-bodies in PNS).
The cell body of the second neuron (called the ________) is found within the ______ and it’s axon terminates on the _______.
The cell body of the first neuron (called the Pre-ganglionic neuron) is found within the CNS and it’s axon terminates in a Ganglion (cluster of cell-bodies in PNS).
The cell body of the second neuron (called the Post-ganglionic Neuron) is found within the Ganglion and it’s axon terminates on the Effector Organ.
How many pairs of spinal nerves are there?
What are they divided into?
31
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Each spinal nerve innervates a specific area of the skin called a ______ and a specific set muscles called a _____
Each spinal nerve innervates a specific area of the skin called a dermatome and a specific set muscles called a myotome
Where is the spinal cord found?
In the spinal Canal of the Vertebra column
What are three functions of the spinal cord?
- Relays signals from the sensory receptors to the brain and from the brain to the effector organs
- Contains neuronal circuitry that generates reflexes and simple rhythmic movements such as walking
- Controls breathing
What is De-afferentation?
Loss of sensory inputs
-has a severe impact on our ability to control our bodies
Sensory afferents ______ (split) into _____ and _____ axons
Sensory afferents bifurcate (split) into ascending and descending axons
The ascending axons (of sensory afferents) form the ______ which ascend to the ______ carrying sensory info to the brain
The ascending axons (of sensory afferents) form the Dorsal Column which ascend to the brainstem carrying sensory info to the brain
The descending sensory afferent axons travel ____ (towards the tail) for 2-3 spinal segments. Every mm or so for the 2-3 segments, the ascending and descending axons send branches into the ______ of the spinal cord which synapse on ______ and ______
The descending sensory afferent axons travel caudally (towards the tail) for 2-3 spinal segments. Every mm or so for the 2-3 segments, the ascending and descending axons send branches into the grey matter of the spinal cord which synapse on interneurons and motorneurons
Where are motor neurons located in the spinal cord?
Their efferent axons leave the spinal cord and form the _______
In the ventral horn
Their efferent axons leave the spinal cord and form the ventral roots
The Spinothalamic Tract (a sensory tract) mediates _____ sensation
Pain
The Spinocerebellar tracts transmit signals from _____ to the _____
The Spinocerebellar tracts transmit signals from muscle receptors to the cerebellum
The dorsal (posterior) columns convey _____ information from _____ and ____ receptors from the leg (______ portion) and arms (_____ portion) to sensory cortex via neurons in the thalamus
The dorsal (posterior) columns convey sensory information from skin and joint receptors from the leg (gracilis portion) and arms (cuneate portion) to sensory cortex via neurons in the thalamus
Which two spinal tracts originate from the brainstem?
- (from latter vestibular nucleus)
- (from reticular formation (nuclei))
Reticulospinal and Vestibulospinal Tracts
Which tract originates ipsilaterally from the motor cortex of the brain?
Anterior Corticospinal tract
Which spinal tract originates ipsilaterally from the Red Nucleus in the Midbrain
Rubrospinal tract
Which spinal tract originates contralaterally from the motor cortex?
Lateral corticospinal tract
How is the knowledge of dermatomes used clinically?
Helps determine the level of spinal cord injury
The ____ (number) cervical nerves mediate sensory info from:
8 cervical nerves mediate sensory info from the arms
The ____ (number) thoracic nerves mediate sensory information from the _____
The 12 (number) thoracic nerves mediate sensory information from the abdomen (trunk)
The ____ lumbar, ____ sacral and __ coccygeal nerves mediate sensory info from the _____ and ____
The 5 lumbar, 5 sacral and 1 coccygeal nerves mediate sensory info from the legs and feet
What is shingles?
Occurs when neurons in the dorsal root ganglia (often in just one or two segments) become infected with a virus related to chicken pox
What is tetraplegia (quadriplegia)?
- Paralysis in all four limbs
- Paralysis of hand and finger movements but not paralysis of breathing or heart rate.
- Results from a cervical injury (eg complete transection) at C6 or C7
What will be affected if someone has a spinal cord injury at L1 or L2?
What is this type of paralysis called?
Only functions below that level
= paraplegia
- Hands, fingers, wrists and elbows will all be able to move
- breathing, heart rate and blood pressure will all be normal
- Voluntary movements of the legs and voluntary and reflex control of the bladder, bowel and sex functions will be affected
