Lecture 8. CNS

Question 1

What constitutes the central nervous system

Answer 1

brain and spinal cord

Question 2

What are the 3 segments of the brain (What are the embrologic names)?

Answer 2

1. forebrain (prosencephalon)
2. midbrain (mesencephalon)
3. hindbrain (rhombencephalon)

Question 3

What are the subdivisions of the forebrain?

Answer 3

1. telecephalon ( cerebrum)

2. diencephalon (thalamus)

Question 4

Describe the diencephalon

Answer 4

structures which surround the 3rd cerebral ventricle and is a narrow gap sitting at the midline

Question 5

What are the subdivisions of the midbrain

Answer 5

It has no subdivision

Question 6

What are the subdivisions of the hindbrain

Answer 6

1. metencephalon ( pons +cerebellum)

2. mylencephalon ( medulla oblongata)

Question 7

What constitutes the Peripheral nervous system?

Answer 7

• cranial nerves (12 pairs)

- spinal nerves (31 pairs)

Question 8

What constitutes the brain stem?

Answer 8

medulla oblongata + pons+ midbrain

Question 9

What surrounds the diencephalon

Answer 9

1. right and left hemisphere

Question 10

What is the purpose of the foldings on the cerebral hemisphere?

Answer 10

To increase the surface area.

Question 11

How many grades of the foldings are there?

Answer 11

3 grades
grade 1: present in everyone
grade 2: present in 70%-75% of people
grade 3: present in 10-15% of people

Question 12

What is the functional classification of the nervous system

Answer 12

1. somatic nervous system

2. autonomic nervous system

Question 13

What is the somatic nervous system

Answer 13

collects sensory information from the external environment and initiates motor info to skeletal muscles

Question 14

What is the autonomic /visceral nervous system

Answer 14

it collects sensory info from the internal environment targets motor info to smooth muscles and glands

Question 15

Where are the enlargements of the spinal cord?

Answer 15

1. cervical enlargement

2. lumbar enlargement

Question 16

Why are there enlargements

Answer 16

• there are more nerve cell bodies due to the formation of motor neurons
• will give rise to nerves that will supply the upper limbs for cervical and lumbar for lower limbs

Question 17

What is the end of the spinal cord called

Answer 17

conus medullaris

Question 18

What is the position on the vertebrae level ( NOT vertebrae segments) where the conus medullaris is (end of spinal cord).

Answer 18

In between L1 and L2 of the vertebrae

Question 19

What is the arrangement of white matter and gray matter in the spinal cord

Answer 19

white matter surrounds the gray matter ( which is a core)

Question 20

what are the grooves present at the anterior(=ventral) and posterior(=dorsal) end of the spinal cord

Answer 20

1. ventral median fissure (= anterior median fissure)

2. dorsal median sulcus ( =posterior median sulcus)

Question 21

What is the difference between fissure and sulcus

Answer 21

fissure is typically deeper and wider

Question 22

There are nerve fibers extending from the anterior median fissure - what structure arises as a result

Answer 22

ventral root/anterior root

Question 23

There are nerve fibers extending from the posterior median fissure - what structure arises as a result

Answer 23

dorsal root/ posterior root - which associates with the ganglion

Question 24

What is a ganglion?

Answer 24

cluster of nerve cell bodies sitting outside the CNS

Question 25

What are the 3 regions of the gray matter in the spinal cord?

Answer 25

1. anterior horn 2. posterior horn 3. lateral horn

Question 26

Which horns are present throughout the length of the spinal cord

Answer 26

anterior and posterior horn are present throughout the length of the spinal cord

Question 27

What does the anterior horn of the spinal cord contain

Answer 27

carries cell bodies of motor neuron

Question 28

What does the posterior horn of the spinal cord contain

Answer 28

sensory neurons are contained along the posterior horn of the spinal cord

Question 29

Where can the lateral horn be found

Answer 29

found in T1 -L2 AND S2-S4

Question 30

What neurons are found in the lateral horn

Answer 30

T1-L2 houses sympathetic neurons | S2-S4 houses parasympathetic neurons

Question 31

What are the regions of white matter

Answer 31

1. dorsal (=posterior) funiculus( = column ) 2. ventral funiculus 3. lateral funiculus

Question 32

Describe the myleinated fibers at the white columns ( of the white matter)

Answer 32

fibers can be ascending or descending ascending: carry sensory info descending: carry motor impulses

Question 33

What are bundles

Answer 33

millions of nerve fibers | AKA specific tracks that carry either sensory or motor information

Question 34

What does the posterior column typically contain

Answer 34

carries sensory tracks

Question 35

What does the lateral column carry

Answer 35

they carry mix tracks - both sensory and motor

Question 36

What does the anterior column carry

Answer 36

they carry mix tracks - both sensory and motor

Question 37

What are spinal cord segments

Answer 37

they refer to a sectioned part of the spinal segments

Question 38

Which part of the brain gathers proprioceptor information

Answer 38

cerebellum

Question 39

What does the medial lemiscus track do

Answer 39

connects information regarding touch and unconscious proprioception

Question 40

Where does the 1st order neuron sit

Answer 40

dorsal root ganglia

Question 41

Where are the 2nd order neuron

Answer 41

for the medial lemniscus the 2nd order neuron site in the medulla oblongata

Question 42

What do we call when the nerve sections crosses the midline

Answer 42

Decussation

Question 43

What is the medial lemiscus

Answer 43

are the axons of the 2nd order neuron that crosses the midline (only AFTER it crosses midline)

Question 44

What is the nucleus gracilis and nucleus cuneatus

Answer 44

are the locations of the axons of the 2nd order neuron

Question 45

Where does the medial lemiscus go to meet the 3rd order neuron

Answer 45

It passes through the pons and cerebellum to enter the midbrain and meets the 3rd order neuron at the thalamus. The 3rd order neuron sends information to the cortex

Question 46

What is the disease that attacks the dorsal column of the spinal cord - what happens?

Answer 46

patient loses sense of touch and position. Syphilis. tabes dorsalis

Question 47

What does the cortex of the brain refer to?

Answer 47

gray matter of the brain

Question 48

Where is the start and end of the spinal cord

Answer 48

starts at the magnum foraman and ends at the L1-L2 vertebrae level