Lecture 13 CNS

Question 1

Development of the CNS

Answer 1

CNS develops from neural tube of embryo starting around 3 weeks
anterior neural tube first differentiates into forebrain, midbrain, and hindbrain (4weeks)
forebrain greatly enlarges to form cerebral hemispheres

Question 2

Supporting structures of the CNS

Answer 2

meninges
brain ventricles and cerebrospinal fluid (CSF)
Glial cells

Question 3

Meninges

Answer 3

Dura mater - outer layer
Arachnoid mater - middle
Pia mater - inner layer

Question 4

Brain ventricles and CSF

Answer 4

CSF is produced by the choroid plexuses of the brain ventricles
CSF circulates through ventricles and into subarachnoid space
CSF composition is regualted; low protein concentration compared to plasma

Question 5

Glial cells

Answer 5

supporting cells of the NS 
astrocytes 
microglia
oligodendrocytes 
ependymal cells

Question 6

Astrocytes

Answer 6

provide physical and metabolic support to neurons
blood-brain barrier- tight junction between capillary endothelial cells
regulates passage of substances from blood to CNS interstitial fluid

Question 7

microglia

Answer 7

phagocytes, protective functions

Question 8

oligodendrocytes

Answer 8

myelinate axons in CNS

Question 9

ependymal cells

Answer 9

produce CSF

Question 10

Spinal Cord

Gray matter

Answer 10

nuclei, contain cell bodies, dendrites, axon terminals integration areas of CNS
dorsal (posterior) horn
ventral (anterior) horn

Question 11

Spinal Cord

White matter

Answer 11

tracts (bundles of axons in the CNS)
contains myelinated areas
conduct APs over long distances
ascending tracts & descending tracts

Question 12

Ascending tracts

Answer 12

sensory information

carries info to the brain in the dorsal white columns

Question 13

Descending tracts

Answer 13

motor information
down to appropriate level of the spinal cord and then out to the appropriate body part
in lateral anterior parts of white matter

Question 14

Ganglia

Answer 14

clusters of cell bodies in the PNS

Question 15

Spinal nerves

Dorsal Root

Answer 15

incoming axons of sensory neurons

cell bodies in dorsal root ganglia

Question 16

Spinal nerves

Ventral Root

Answer 16

outgoing axons of motor neurons

cell bodies in ventral horn

Question 17

How many pairs of spinal nerves

Answer 17

31 pairs

C1-8, T1-12, L1-5, S1-5 Co1

Question 18

Spinal Reflexes

Parts of the reflex arc

Answer 18

sensory receptor 
sensory neuron 
integration center
motor neuron 
effector (muscle)

Question 19

2 spinal reflexes

Answer 19

monosynaptic reflex (e.g. muscle spindle stretch reflex)
polysynaptic reflex (e.g withdrawal reflex and crossed extensor reflex

Question 20

Brain stem

Answer 20

medulla ,pons, and midbrain
transition from spinal cord to higher brain regions
sensory motor tracts pass through
origins of cranial nerves

Question 21

reticular formation

Answer 21

network of neurons involved in arousal of cerebral cortex (sleep/wake)

Question 22

Medulla Oblongata

Answer 22

ascending (somatosensory) tracts convey sensory information to higher brain areas
descending (corticospinal) tracts carry motor signals, cross over in pyramids of the medulla
respiratory and cardiovascular control centers
other involuntary control centers (swallowing, vomiting)

Question 23

Pons

Answer 23

connections between cerebellum and other CNS areas

respiratory centers coordinate with medulla to control breathing

Question 24

Midbrain

Answer 24

visual and auditory reflexes

role in unconscious motor control (red nucleus, substantia nigra)

Question 25

Cerebellum

Answer 25

major role in coordination of movement
cortex (gray matter)
arbor vitae (white matter)

Question 26

Parts of the diencephalon

Answer 26

thalamus
hypothalamus
pineal gland

Question 27

thalamus

Answer 27

sensory “relay station” from lower CNS centers to the cerebral cortex

Question 28

hypothalamus

Answer 28

major center for homeostasis
regulates appetite, thirst, body temp
regulate endocrine function via control of the pituitary gland
activates sympathetic division of ANS
mediates physiological responses of emotional states (via autonomic NS)

Question 29

Pineal gland

Answer 29

endocrine gland

secretes melatonin

Question 30

Cerebrum

Answer 30

higher brain functions, sensory perception, voluntary control of movement
lobes: frontal, parietal, temporal, occipital

Question 31

Cerebral gray matter

Answer 31

cerebral cortex
basal ganglia
limbic system

Question 32

Cerebral white matter

Answer 32

association fibers
commissural fibers (corpus callosum) - connect 2 hemispheres
projection fibers - ascending and descending tracts

Question 33

Basal ganglia

Answer 33

deep gray matter areas, involved in subconscious control of movement
part of cerebrum

Question 34

Limbic system

Answer 34

emotional brain
amygdala - control center of strong emotions (fear, anger) role in memory processing
hippocampus - major role in consolidation of long term memory

Question 35

Cerebral cortex

Answer 35

highest level processing and integration area
what makes you, you
gyri and sulci increase surface area
6 distinct cell layers of cortex
functional areas of the brain
cerebral lateralization (left brain- right brain)

Question 36

Frontal love

Answer 36

primary motor area
speech (Broca’s) area
prefrontal cortex - higher level thinking, plannin, judgement, personality

Question 37

Parietal lobe

Answer 37

primary somatosensory area

sensory association areas

Question 38

Occipital lobe

Answer 38

visual cortex

Question 39

temporal lobe

Answer 39

auditory cortex 
language association (Wernicke's) area