L2 Organization of the Nervous System I

Question 1

what makes up the PNS?

Answer 1

neuronal processes + Glia outside the CNS

Question 2

what makes up the somatic nervous system?

Answer 2

afferent and efferent structures of the PNS that communicate between skin, skeletal muscles, or joints and the CNS

Question 3

what makes up the autonomic nervous system?

Answer 3

parasympathetic, sympathetic, enteric

Question 4

what makes up the boundary between the PNS and the CNS?

Answer 4

• shift from oligodendrocytes - CNS to schwann cells - PNS = Redlich Obersteiner’s zone
• the axons here cannot regenerate - they can in limbs sometimes etc.

Question 5

what are the 5 parts of the brain?

Answer 5

1. telencephalon - cerebrum (and cortex)
2. diencephalon (between 2 hems = 3rd ventricle with CSF
3. mesencephalon - midbrain
4. metencephalon - pons + cerebellum
5. myelencephalon - medulla oblongata

Question 6

what are the lobes of the brain?

Answer 6

• frontal
• temporal
• parietal
• occipital
• limbic - only seen from medial surface, joins the other lobes together
• insular - hidden from view

Question 7

where is the grey and white matter in the brain?

Answer 7

grey is outside/surface
white is inside
*opposite of spinal cord

Question 8

when a person shows back extended and arms outstretched/extended, what should I suspect?

Answer 8

midbrain injury

Question 9

what makes up the myelon and what is its function?

Answer 9

spinal cord

-contains cells and axonal pathways related to somatosensory, motor and autonomic function

Question 10

What are the 6 layers of the cerebral cortex?

Answer 10

1. molecular layer
2. external granular layer
3. external pyrimidal layer (small pyrimidal cells)
4. internal granular layer
5. ganglionic layer (large pryamidal cells)
6. multiform layer (polymorphus layer)

Question 11

what do pyrimidal cells do?

Answer 11

• yield output pathway from cortex
• layers 2,3,5,6
• largest pyrimidal cells (Betz cells) found in layer 5 of primary motor cortex making synaptic connections with lumbar spinal motor neurons

Question 12

what are all other neurons with cortical cell bodies?

Answer 12

local interneurons

Question 13

All local interneuron have an _____ action?

Answer 13

inhibitory - except spiny stellate cells in layer 4

Question 14

What are thalamic neurons?

Answer 14

most end in layer 4

axons of some thalamic neurons and other neurons regulating cortical excitability end in all layers.

Question 15

what makes up the telencephalon (endbrain derived from rostral prosencephalon)?

Answer 15

-cerebral hemispheres
cerebral cortex
basal ganglia
lateral ventricle + foramina of Monro
closely tied to CN I olfactory n.

Question 16

what makes up the diencephalon (inter brain - derived from the caudal prosencephalon)?

Answer 16

thalamus
hypothalamus + pituitary
subthalamus
epithalamus
third ventricle
CN II Optic n.

Question 17

what makes up the mesencephalon (midbrain)?

Answer 17

tegmentum - floor
tectum - roof
cerebral aqueduct
CN III and IV - oculomotor and trochlear n.

Question 18

what makes up the met encephalon (derived from rhombencephalon)?

Answer 18

pons
cerebellum
rostral fourth ventricle
CN V-VIII - trigeminal, abducens, facial, vestibulocochlear

Question 19

what makes up the myelencephalon (derived from rhombencephalon)?

Answer 19

medulla oblongata
causal fourth ventricle - foramen of Magendi and Luschka - central canal of medulla is continous with spinal cord
CN IX-XII glossopharyngeal, vagus, spinal accessory, hypoglossal.

Question 20

what is the function of the cerebral hemisphere (cortex, white matter, BG, amygdala, hippocampal formation)?

Answer 20

motor activity - also perceptual, cognitive, visceral and emotional functions

commonly divided into lobes

Question 21

what does the frontal lobe do?

Answer 21

motor planning and execution, language production, judgement, and working (ST) memory

Question 22

what does the parietal lobe do?

Answer 22

somatosensory processing

Question 23

what does the occipital lobe do?

Answer 23

visual processing

Question 24

what does the temporal lobe do?

Answer 24

auditory processing

Question 25

what does the limbic lobe do?

Answer 25

functionally tied to emotion and memory.

Question 26

what is the function of the insular lobe?

Answer 26

varied function - autonomic and interoceptive

Question 27

what does the thalamus do?

Answer 27

modulates and relays sensory info and motor info from BG and cerebellum to the cerebral cortex

Question 28

what does the hypothalamus do?

Answer 28

homeostasis and reproduction

Question 29

what does the subthalamus do?

Answer 29

motor and sensory function

Question 30

what does the epithalamus do?

Answer 30

endocrine function

Question 31

what does the midbrain do?

Answer 31

contains neurons forming part of the motor system regulates eye movements promotes alertness/arousal

Question 32

what does the pons do?

Answer 32

ventral - relay motor info from cerebral cortex to cerebellum dorsal - respiration, taste, circuits controlling sleep/wake cycles regulates motor function

Question 33

what does the cerebellum do?

Answer 33

receives somatosensory info from spinal cord, motor info from cerebral cortex and vestibulo info from organs of inner ear maintains posture and balance smoothes and coordinates movement by regulating motor centers

Question 34

what does the medulla oblongata do?

Answer 34

some nuclei control respiration, BP and motor activity of mouth other nuclei receive sensory info from chemoreceptors and mechanoreceptors

Question 35

whats in the molecular layer?

Answer 35

- few neuronal sonata - apical dendrites located in deeper cortical layers - axons passing through or making cnx - axons arising from this layer travel parallel to pia

Question 36

whats in the external granular layer

Answer 36

- small granule cells (local interneurons that inhibit other cortical cells) and some slightly larger pyrimidal cells - communcations with opsilateral cortical areas (via association fibers)

Question 37

whats in hte external pyramidal layer?

Answer 37

- small to med pyramidal neurons projecting from cortex | - communications with homotopic contralateral cortices (via commisural fibers)

Question 38

whats in the internal granular layer?

Answer 38

- no pyramidal neurons - interneurons receive ascending sensory input and projecting to layers II and III - contains dense band of tangenital axons that form the outer band of Baillarger - hypertrophic and visible to naked eye in a discrete occipital region

Question 39

whats in the internal pyramidal layer

Answer 39

med to lrg pyramidal neurons - major source of cortical output to brainstem and SC - contains dense band of tangenital axons

Question 40

whats in the multiform layer?

Answer 40

- assortment of cell types, few pyramidal cells - small cells receive input from thalamus and from layers II, III, and V - axons of the cells project to superficial cortical layers and to the thalamus

Question 41

what does the Golgi stain reveal?

Answer 41

morpholog of some neurons

Question 42

what does the Niddl stain reveal?

Answer 42

rough ER of the nerve cell bodies

Question 43

what does the Weigert stain reveal?

Answer 43

myelin of axons

Question 44

what layer are pyramidal cells found and where are the largest ones found?

Answer 44

II, III, V and IV largest found in V of primary motor cortex and can make synaptic cnx with caudal spinal motor neurons

Question 45

where do most thalamo-cortical neurons end?

Answer 45

layer IV