Neuro - Pt II Brainstem and Reflexes

Question 1

What are the 3 sections of the brain stem?

Answer 1

Midbrain

Pons

Medulla

Question 2

Which type of “matter” connects the cerebral cortex to the brain stem?

Answer 2

Gray matter

Question 3

Midbrain:

• important relay center for [] and [] pathways and contains [] as well as [] and [] fiber tracts
• Corpora []
  
  • 2 superior colliculi are involved in []reflexes
  • 2 inferior colliculi are involved in relaying [] input
• Cerebral peduncles: contain [] and [] fiber tracts
• Red nucleus: connects to [] and [] and is inolved in [] functions
• Sbstantia nigra: connects to [] ganglia and is involved in [] coordination

Answer 3

Midbrain:

• important relay center for sensory and motor pathways and contains nuclei as well as ascending and descending fiber tracts
• Corpora quadragemini
  
  • 2 superior colliculi are involved in visual reflexes
  • 2 inferior colliculi are involved in relaying auditory input
• Cerebral peduncles: contain ascending and descending fiber tracts
• Red nucleus: connects to cerebrum and cerebellum and is inolved in motor functions
• Sbstantia nigra: connects to basal ganglia and is involved in motor coordination

Question 4

Midbrain:

• important relay center for sensory and motor pathways and contains nuclei as well as ascending and descending fiber tracts
• [] []
  
  • 2 superior colliculi are involved in visual reflexes
  • 2 inferior colliculi are involved in relaying auditory input
• [] [] contain ascending and descending fiber tracts
• [] []: connects to cerebrum and cerebellum and is inolved in motoro functions
• [] []: connects to basal ganglia and is involved in motoro coordination

Answer 4

• important relay center for sensory and motor pathways and contains nuclei as well as ascending and descending fiber tracts
• Corpora quadragemini
  
  • 2 superior colliculi are involved in visual reflexes
  • 2 inferior colliculi are involved in relaying auditory input
• Cerebral peduncles: contain ascending and descending fiber tracts
• Red nucleus: connects to cerebrum and cerebellum and is inolved in motoro functions
• Substantia nigra: connects to basal ganglia and is involved in motoro coordination

Question 5

Pons:

• integration of [] and other functions. Involved in control of different [] functions and contains relay stations for control of activities initiated at [] levels of the brain
• Surface fibers connect to the []
• Also contains several nuclei associated with [] nerves
• Contains the 2 respiratory centers: [] and []

Answer 5

• integration of motor and other functions. Involved in control of different autonomic functions and contains relay stations for control of activities initiated at higher levels of the brain
• Surface fibers connect to the cerebrellum
• Also contains several nuclei associated with cranial nerves
• Contains the 2 respiratory centers: apneustic and pneumotaxic

Question 6

Medulla:

• All [] and [] tracts between the brain and spinal cord pass through here
  
  • The crossing tracts form visible []
• Contains several nuclei associated with the [] nerves
• The three important centers in the medulla: [], [], and [] centers
• Generally controls functions which are confined to [] organ.

Answer 6

• All ascending and descending tracts between the brain and spinal cord pass through here
  
  • The crossing tracts form visible pyramids
• Contains several nuclei associated with the cranial nerves
• The three important centers in the medulla: Vasomotor, Cardioinhibitory, and Medullary Respiratory Center
• Generally controls functions which are confined to one organ.

Question 7

Reticular Formation:

• Complex network of nuclei and nerve fibers within the [bunch of areas….]
• Activated in a []-[] fashion by many types of sensory information
• Organizes [] [] patterns involving the whole body
• Nerve fibers from here project diffusely to the [] cortex

Answer 7

• Complex network of nuclei and nerve fibers within the midbrain, pons, medulla, thalamus and hypothalamus
• Activated in a non-specific fashion by many types of sensory information
• Organizes basic behavioral patterns involving the whole body
• Nerve fibers from here project diffusely to the cerebral cortex

Question 8

The “core” of the CNS can be thought of as the [] []- [] [] continuum

Answer 8

reticular formation-intermediate zone

Question 9

1. [] horns receive sensory input
2. [] ventral horns contain cell bodies of motor neurons
3. Intermediate zone houses [] between sensory and motor neurons

Answer 9

1. Dorsal
2. Ventral
3. synapses

Question 10

Vasomotor center in the medulla, is involved in regulating [] [] diameter

Answer 10

blood vessel

Question 11

Cardioinhibitory center [] heart rate and [] force of contraction

Answer 11

Slows; decreases

Question 12

Medullary Respiratory Center is the [] [] for breathing

Answer 12

pattern generator

Question 13

The alpha motor neuron goes from the [] [] to the [] []

Answer 13

spinal cord to the skeletal muscle

Question 14

Spinal Cord:

• Contains [] centers and can serve as an [] area for spinal reflexes
• [] divisions of CNS can send signals to the spinal cord to trigger reflex
• Some reflexes are evoked without [] involvement
• Many spinal cord reflex involve: posture, walking, withdrawl etc…

Answer 14

Spinal Cord:

• Contains reflex centers and can serve as an integrative area for spinal reflexes
• Upper divisions of CNS can send signals to the spinal cord to trigger reflex
• Some reflexes are evoked without brain involvement
• Many spinal cord reflex involve: posture, walking, withdrawl etc…

Question 15

• The 3 major ascending, or [], tracts in the spinal cord are: []
• The 2 major descending, or [], tracts in the spinal cord are: []

Answer 15

• The 3 major asceding, or sensory, tracts in the spinal cord are: Spinocerebellar, Spinothalamic, and Dorsal column/medial lemniscal
• The 2 major descending, or motor, tracts in the spinal cord are: Corticospinal and Rubrospinal

Question 16

Spinocerebellar spinal tract:

1. carries sensory input from [] receptors to the []
2. Considered to be [] []

Answer 16

1. muscle receptors to the cerebellum
2. extra pyramidal

Question 17

Spinothalamic spinal tract:

1. carries sensory information from [] and [] receptrs to the thalamus and cortex-[]-[]-[]
2. Considered to be []

Answer 17

1. carries sensory information from pain and temperature receptors to the thalamus and cortex-post-central-gyrus
2. considered to be pyramidal

Question 18

Dorsal column spinal tract:

• Also called the [] []
• Carries sensory information from [] and [] receptors to the thalamus and cortex-[]-[]-[].
• Considered to be []

Answer 18

• Also called the medial lemniscal
• Carries sensory information from joint and touch receptors to the thalamus and cortex-post-central-gyrus.
• Considered to be pyramidal​

Question 19

The corticospinal spinal column tract:

1. carries information from the [] cortex to [] [] of the skeletal muscle
2. Considered to be []

Answer 19

1. carries information from the motor cortex to motor neurons of the skeletal muscle
2. Considered to be pyramidal

Question 20

Rubrospinal spinal column tract:

1. connects the red nucleus to the [] and []
2. Conisered to be [] []

Answer 20

1. connects the red nucleus to the cerebrum and cerebellum
2. Conisered to be extra pyramidal

Question 21

The final common output from pyramidal/extra pyramidal tracts are the [] [] [].

Answer 21

lower motor neurons

Question 22

The simplest reflex arc =

• Involves a single [] between afferent and efferent neuron
• Contains large, fast [] [] fibers

Answer 22

Monosynaptic Reflex

• Involves a single synapse between afferent and efferent neuron
• Contains large, fast afferent myelinated fibers

Question 23

Muscle Spindle:

• Consists of [] [] fibers in a connective tissue capsule
• Intrafusal fibers are in [] to the extrafusal fibers
• The sensory nerve of the muscle spindle is a fast [] fiber
• The sensory nerve synapses on the [] [] neuron which supplies the extrafusal fibers
• The motor nerve supply to the muscle spindle is know as the [] [] nerve

Answer 23

• Consists of intrafusal muscle fibers in a connective tissue capsule
• Intrafusal fibers are in parallel to the extrafusal fibers
• The sensory nerve of the muscle spindle is a fast 1a fiber
• The sensory nerve synapses on the alpha motor neuron which supplies the extrafusal fibers
• The motor nerve supply to the muscle spindle is know as the gamma motor nerve

Question 24

Activation of the gamma motor neuron causes the muscle spindle to [], causing excitation of its sensory [] nerve fiber. Sufficient [] would causee the regular contractile units of the muscle to [] .

Answer 24

Activation of the gamma motor neuron causes the muscle spindle to contract, causing excitation of its sensory afferent nerve fiber. Sufficient excitation would cause the regular contractile units of the muscle to contract.

Question 25

The function of the muscle spindle is to maintain [] []

Answer 25

The function of the muscle spindle is to maintain muscle length

Question 26

The muscle spindle provides feedback about the muscle length and the [] [] [] in muscle length

Answer 26

The muscle spindle provides feedback about the muscle length and the rate of change in muscle length

Question 27

1. T/F - Gamma efferent discharge directly leads to muscle contraction
2. Gamma efferent discharge leads to a [] [] of the extrafusal muscle fibers

Answer 27

1. False - they do not directly lead to contraction
2. Gamma efferent discharge leads to a reflex contraction of the extrafusal muscle fibers

Question 28

1. Gamma efferent discharge [] intrafusal fibers which stretches the muscle spindles - this causes the reflex [] of anatomical muscle
2. With gamma efferent discharge, the muscle spindle is more [], and thus, is more sensitive to changes in [] []
3. The firing rate of the 1a [] fiber is proportional to the stretch of the [] fiber

Answer 28

1. Gamma efferent discharge contracts intrafusal fibers which stretches the muscle spindles - this causes the reflex contraction of anatomical muscle
2. With gamma efferent discharge, the muscle spindle is more taught, and thus, is more sensitive to changes in muscle length
3. The firing rate of the 1a afferent fiber is proportional to the stretch of the intrafusal fiber

Question 29

Types of Intrafusal Fibers:

1. Nuclear Bag fibers: detect fast, [] changes in muscle length and tension
2. Nuclear Chain FIbers: Detect [] changes in muscle length and tension

Answer 29

1. Nuclear Bag fibers: detect fast, dynamic changes in muscle length and tension
2. Nuclear Chain FIbers: Detect static changes in muscle length and tension

Question 30

Poly-Synaptic Reflex:

• Reflex arcs where there are one or more [] between the afferent and efferent neurons
• T/F - only 1 interneurons is used

Answer 30

• Reflex arcs where there are one or more interneurons between the afferent and efferent neurons
• False - the number of interneurons varies

Question 31

The Inverse Stretch Reflex:

• When tension becomes great enough, contraction suddenly ceases and the muscle []
• Golgi Tendon Organ (receptor): Its afferent are called [] fibers, and are [] to the alpha motor neuron
  
  • Located in [] with the muscles and tendons
• Stimulation leads to the production of []

Answer 31

• When tension becomes great enough, contraction suddenly ceases and the muscle relaxes
• Golgi Tendon Organ (receptor): Its afferent are called 1b fibers, and are inhibitory to the alpha motor neuron
  
  • Located in series with the muscles and tendons
• Stimulation leads to the production of IPSP’s

Question 32

Golgi Tendon Organ:

• Utilizes a single inhibitory [] to relax muscle
• Whenever a muscle stretches, the GTO is [] in some capacity
• Stimulated by muscle [] or []
• This is a great [] detector

Answer 32

• Utilizes a single inhibitory interneuron to relax muscle
• Whenever a muscle stretches, the GTO is activated in some capacity
• Stimulated by muscle stretch or contraction
• This is a great tension detector

Question 33

The Withdrawal Reflex

1. A []-[] reflex elicited by [] stimuli
2. A [] reflex that causes withdrawal from site of stimulation
3. It [] spinal pathways from other reflex activity taking place at the moment.
   
   1. Reflex = causes flexor muscles [] and extensor muscle []
4. The [] of the reflex depends on the site of pain.

Answer 33

1. A poly-synaptic reflex elicited by noxious stimuli
2. A protective reflex that causes withdrawal from site of stimulation
3. It preempts spinal pathways from other reflex activity taking place at the moment.
   
   1. Reflex = causes flexor muscles contraction and extensor muscle relaxation
4. The pattern of the reflex depends on the site of pain.

Question 34

Reciprocal Innervation

1. [] of one group of muscles is often associated with the [] of another gorup of muscles

Answer 34

Excitation of one group of muscles is often associated with the inhibition of another gorup of muscles

Question 35

T/F

The crossed extensor reflex does not use reciprocal innervation.

Answer 35

False

it does.

Question 36

Somatic motor activity depends on the [] and [] [] [] of spinal motor neurons and neurons in the motor nuclei of cranial nerves

Answer 36

Somatic motor activity depends on the pattern and rate of discharge of spinal motor neurons and neurons in the motor nuclei of cranial nerves