Chapter 9 Flashcards
What is the function of the dorsal root?
They carry sensor/afferent neurons from receptors to the spinal cord (afferent)
What is the function of the dorsal root ganglia?
It transmits sensory info from the PNS to the CNS
What is the function of the Ventral root?
They carry motor/efferent neurons away from the spinal cord to an effector (efferent)
What is the function of the Dorsal gray horn?
cell bodies of interneurons that receive somatic and visceral sensory input (afferent)
What is the function of the Ventral gray horn?
Cell bodies of somatic motor neurons that the axons exit the ventral root to the skeletal muscles for motor output (efferent)
What is the function of the Sensory neuron?
to detect stimuli from the environment and send that information to the brain for processing
Where is the cell body, dendrites, and axons located in a sensory neuron?
Dendrites: In the nocireceptors (example in the hand getting the information)
Cell body: In the dorsal root ganglion OUTSIDE OF THE SPINAL CORD
Axons: DORSAL ROOT Then the axon goes to the interneurons in the spinal cord (DORSAL HORN)
Where is the cell body, dendrites, and axons located in a Interneuron?
Cell bodies: in ALL dorsal horns
Dendrites: dorsal horns
Axons: dorsal horns but extends to ventral horns to connect to the motor neuronss
Where is the cell body, dendrites, and axons located in a Motor neuron?
Cell body: In the gray matter of the spinal cords ventral horn
Dendrites: near the cell body in the gray matter
Axons: Goes out of the ventral horn to its effector (ventral root)
What is the function of the Afferent path?
To carry sensory information toward the brain (sensory input)
What is the function of the Efferent path?
To carry motor commands to the spinal cord (motor output)
What is the function of the ascending tract?
To carry sensory information toward the brain (sensory input) FROM SENSORY RECEPTORS TO THE BRAIN
What is the function of the descending tract?
To carry motor commands to the spinal cord (motor output) FROM THE BRAIN TO EFFERENT MUSCLES
Label the ascending and descending tracts and which pathway (afferent or efferent) belongs to it. in Pic #1.
Blue line: Ascending tract (Afferent)
Red line: Descending tract (efferent)
Label these on pic #2
* Dorsal root
* Dorsal root ganglia
* Ventral root
* Dorsal gray horn
* Ventral gray horn
* Sensory neuron
- Motor neuron
- White matter
- gray matter
- Dorsal root (#8)
- Dorsal root ganglia (#9)
- Ventral root (#5)
- Dorsal gray horn (#6)
- Ventral gray horn (#4)
- Sensory neuron (#10)
- Motor neuron (#2)
- White matter (#3)
- gray matter (#1)
List the start and finish of each neuron in an ascending tract.
1st order neurons
2nd order neurons
3rd order neurons
1st order neurons- STARTS: Dendrites (nociceptors), ENDS: Dorsal horn
2nd order neurons- STARTS: Spinal cord, ENDS: thalamus
3rd order neurons- STARTS:thalamus, ENDS: cerebral cortex
List the start and finish of each neuron in an descending tract.
Upper motor neuron
Lower motor neuron
Upper motor neuron- starts in the cerebral cortex or brainstem and ends on a lower motor neuron which then leads to the muscle
Lower motor neuron- in the ventral horn/spine that leads the motor neuron to the target effector
Now put the following process of sensory neurons in order. (which one is a 1st, 2nd, or 3rd neuron)
- The left side of my brain received the information of pain
- The thalamus sent it to the somatosensory cortex in the parietal lobe
- I got bit by a spider on my right hand and it hurt
The left side of my brain received the information of pain (3rd order neuron)
The thalamus sent it to the somatosensory cortex in the parietal lobe (2nd order neuron)
I got bit by a spider on my right hand and it hurt (1st order neuron)
What are the 7 different names for the ascending tract?
- Spinothalamic
- Dorsal Column
- Spinocerebellar
- Cuneocerebellar
- Spinotectal
- Spinoreticular
- Spino-olivary
What are the 5 different names for the descending tract?
- Corticospinal
- Reticulospinal
- Rubrospinal
- Vestibulospinal
- Tectospinal
What are the 5 steps in a reflex arc in order? (what parts are involved)
- Arrival of stimulus and activation of receptor- Sensory receptor
- Activation of sensory neuron- Afferent neuron
- Information processing in the CNS- Integration center
- Activation of a motor neuron- Efferent neuron
- Response by a peripheral effector- effector organ
what is the difference between monosynaptic and polysynaptic reflexes?
Monosynaptic- has 2 neurons, 1 synapse, and NO interneurons, efffects one part of the body
Polysynaptic- Has MORE than 2 neurons, and requires interneurons, effects multiple parts of the body
What are some examples of monosynaptic and polysynaptic reflexes?
monosynaptic- Stretch reflex (patellar reflex)
polysynaptic - Withdrawal reflex (when you touch something hot and pull yourself away from it), Crossed extensor reflex (when you step on something sharp and extend away from it)
When is an interneuron necessary in regards to reflexes?
When it is a polysynaptic reflex, when multiple synapses are involved and need to connected multiple sensory and motor neurons
Describe dura mater in the spinal cord and where is it located?
It is a tough outer single membrane NOT connected to the vertebral bodies
Location: outer layer of the spinal cord
Describe the Arachnoid mater and where it is located in the spinal cord?
It is the middle layer that consists of an arachnoid membrane and arachnoid trabeculae
Location: middle layer between the pia mater and dura mater
Describe the Pia mater and where it is located in the spinal cord?
It is the innermost membrane connected to the spinal cord
Where is the location of the epidural space in the spinal cord? And what makes it different from the subarachnoid space?
Location: It is between the vertebral body and dura mater
It contains adipose tissue NOT cerebral spinal fluid
Where is the location of the subarachnoid space in the spinal cord? And what makes it different from the epidural space?
Location: It is between the arachnoid membrane and the Pia mater.
It contains cerebrospinal fluid
What space in the spinal cord does the epidural and lumbar puncture (spinal tap) go into? (hint they are different spaces)
Epidural: Epidural space
Lumbar puncture (spinal tap): Subarachnoid space
Describe dura mater in the skull and where is it located?
Location: the outermost layer NOT CONNECTED TO THE SKULL
It is a double layer membrane that has NO EPIDURAL SPACE
Is there an epidural space in the brain?
NO THERE IS NOT
What is the sagittal sinus in the brain? Where is it located?
It is between the 2 layers of the dura mater and drains blood and CSF
Describe arachnoid mater in the skull and where is it located?
Location: in between the pia mater and the dura mater
It contains the arachnoid membrane and arachnoid trabeculae and has CSF to cushion the brain
What is the subarachnoid space in the brain? And where is it located?
It is located between the arachnoid membrane and pia mater
It consists of CSF
What are arachnoid granulations in the brain?
They absorb old CSF