OVERVIEW NERVOUS SYSTEM

Question 1

What makes up the structural part of the Nervous System?

Answer 1

The Peripheral Nervous System (ganglia and nerves) and Central Nervous System (gray matter and nuclei, white matter and tracts)

Question 2

What makes up the functional part of the Nervous System?

Answer 2

Visceral and Somatic, which both consist of motor (efferent) and sensory (afferent)

Question 3

parasympathetic

Answer 3

The parasympathetic nervous system affects the same body functions as the sympathetic nervous system, but in a completely different way. It works to slow down certain responses and bring about a state of calm to the body, allowing it to rest, relax, and repair itself. The primary function of the parasympathetic nervous system is to maintain long-term health and a healthy balance across all of the body’s functions. Parasympathetic responses include an increase of digestive enzymes, decreased heart rate, constriction of bronchial tubes in lungs, and more relaxed muscles.

Question 4

Sympathetic

Answer 4

The fight or flight response is commonly known, but what may be lesser known is that this reaction to external stimuli is based completely on the sympathetic nervous system. When we are faced with a perceived threat of any kind, whether physical or emotional, our sympathetic nervous system kicks into gear and brings about automatic and involuntary responses, such as increased heart rate, elevated blood pressure, heightened awareness, elevated respiratory rate, and more sweating. The sympathetic nervous system also shuts down many parasympathetic responses in order to utilize more energy for the fight or flight response.

Question 5

CNS

Answer 5

Brain and Spinal Cord

Question 6

central sulcus

Answer 6

The sulcus between the frontal and parietal lobes

Question 7

Lateral fissure (Sylvian fissure)

Answer 7

The fissure superior to the temporal lobe

Question 8

Parieto-occipital sulcus

Answer 8

The sulcus that runs between the parietal and occipital lobes

Question 9

calcarine fissure

Answer 9

Fissure in the occipital lobe

Question 10

How many pairs of spinal nerves are in the spinal cord?

Answer 10

31 pairs of spinal nerves

Question 11

How many nerves are there in the cervical cord?

Answer 11

8 cervical nerves

Question 12

How many nerves are in the thoracic cord?

Answer 12

12 thoracic nerves

Question 13

How many nerves are in the lumbar cord?

Answer 13

5 lumbar nerves

Question 14

How many nerves are in the sacral cord?

Answer 14

5 sacral nerves

Question 15

How many nerves are in the coccygeal?

Answer 15

1-2 coccygeal

Question 16

What is conus medullaris?

Answer 16

The conus medullaris is the bundled, tapered end of the spinal cord nerves. Situated near the first two lumbar vertebrae, the conus medullaris ends at the cauda equina, a bundle of spinal nerves and nerve roots. Consequently, problems with the conus medullaris often affect the cauda equina.

Question 17

What is cauda equina?

Answer 17

The cauda equina is the continuation of these nerve roots in the lumbar and sacral region. These nerves send and receive messages to and from the lower limbs and pelvic organs. Cauda equina syndrome (CES) occurs when there is dysfunction of multiple lumbar and sacral nerve roots of the cauda equina.

Question 18

posterior root

Answer 18

sensory neurons (pseudounipolar)

Question 19

posterior root ganglion

Answer 19

cell bodies of sensory neurons

Question 20

anterior root

Answer 20

motor neurons (multipolar)

Question 21

ANS =

Answer 21

sympathetic + parasympathetic

Question 22

neuron =

Answer 22

functional unit

of the nervous system

Question 23

Types of neurons

Answer 23

multipolar neurons (99% of all neurons)
pseudounipolar neurons (sensory ganglia)
bipolar neurons (retina, cranial nerve I, cranial nerve VIII)

Question 24

How many layers do the cerebral cortex have?

Answer 24

– six layers

Question 25

Layers of the cerebral cortex-

Answer 25

I. Molecular (plexiform) layer
II. External granular layer
III. External pyramidal layer
IV. Internal granular layer
V. Internal pyramidal layer
VI. Multiform (fusiform) layer

Question 26

I. Molecular (plexiform) layer

Answer 26

Layer I is the molecular layer and contains a few scattered neurons, including GABAergic rosehip neurons.[22] Layer I consists largely of extensions of apical dendritic tufts of pyramidal neurons and horizontally oriented axons, as well as glial cells.

Question 27

II. External granular layer

Answer 27

Layer II, the external granular layer, contains small pyramidal neurons and numerous stellate neurons.

Question 28

III. External pyramidal layer

Answer 28

Layer III, the external pyramidal layer, contains predominantly small and medium-size pyramidal neurons, as well as non-pyramidal neurons with vertically oriented intracortical axons; layers I through III are the main target of interhemispheric corticocortical afferents, and layer III is the principal source of corticocortical efferents.

Question 29

IV. Internal granular layer

Answer 29

Layer IV, the internal granular layer, contains different types of stellate and pyramidal cells, and is the main target of thalamocortical afferents from thalamus type C neurons (core-type )[28] as well as intra-hemispheric corticocortical afferents. The layers above layer IV are also referred to as supragranular layers (layers I-III), whereas the layers below are referred to as infragranular layers (layers V and VI).

Question 30

V. Internal pyramidal layer

Answer 30

Layer V, the internal pyramidal layer, contains large pyramidal neurons. Axons from these leave the cortex and connect with subcortical structures including the basal ganglia. In the primary motor cortex of the frontal lobe, layer V contains giant pyramidal cells called Betz cells, whose axons travel through the internal capsule, the brain stem, and the spinal cord forming the corticospinal tract, which is the main pathway for voluntary motor control.

Question 31

VI. Multiform (fusiform) layer

Answer 31

Layer VI, the polymorphic or multiform layer, contains few large pyramidal neurons and many small spindle-like pyramidal and multiform neurons; layer VI sends efferent fibers to the thalamus, establishing a very precise reciprocal interconnection between the cortex and the thalamus.[29] That is, layer VI neurons from one cortical column connect with thalamus neurons that provide input to the same cortical column. These connections are both excitatory and inhibitory. Neurons send excitatory fibers to neurons in the thalamus and also send collaterals to the thalamic reticular nucleus that inhibit these same thalamus neurons or ones adjacent to them.[30] One theory is that because the inhibitory output is reduced by cholinergic input to the cerebral cortex, this provides the brainstem with adjustable “gain control for the relay of lemniscal inputs”.

Question 32

cell body

Answer 32

contains a nucleus, nucleolus,
Nissl bodies (ribosomes and endoplasmic reticulum), Golgi complexes,
mitochondria, neurofilaments, microtubules

Question 33

dendrites

Answer 33

contains same organelles as cell body except nucleus

Nissl bodies and Golgi complexes only in proximal portion

Question 34

axon

Answer 34

contains mitochondria, neurofilaments

and microtubules, but no protein-making machinery

Question 35

oligodendrocytes

Answer 35

branched processes radiate from the cell body
myelination of CNS axons
multiple internodal segments on multiple axons
multiple sclerosis demyelinates neurons of the CNS
treatment includes interferon
to diminish the immune response

Question 36

astrocytes

Answer 36

numerous thin stellate processes radiate from the cell body
regulation of the extracellular ionic environment
guidance of migrating neurons during brain development
blood-brain barrier
glioblastoma - a multiform severe type of brain tumor

Question 37

Schwann cells

Answer 37

myelination of PNS axons
single internodal segment
axons can regenerate to target

Question 38

sensory ganglia

Answer 38

sensory
pseudounipolar neurons
neuron density higher
satellite cells greater
no synapses

Question 39

autonomic ganglia

Answer 39

motor
multipolar neurons
neuron density lower
satellite cells fewer
synapses

Question 40

non -neuronal cells - CNS

Answer 40

oligodendrocytes - myelinate axons
ependymal cells - line ventricle (brain)
astrocytes - have numerous functions
microglial cells - phagocytose (swallow) foreign matter

Question 41

non -neuronal cells -PNS

Answer 41

neurolemmocytes - (Schwann cells) myelinate axons

satellite cells - are support cells for PNS neurons