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Flashcards in CNS Deck (156):
1

What are the two parts of the CNS?

brain and spinal cord

2

evolution of a CNS with an elaboration of the anterior end of the CNS along with an increase in the number of neurons in the head

cephalization

3

a thickening of the surface ectoderm along the dorsal midline of the embryo that eventually becomes the CNS

neural plate

4

the invagination of the neural plate

neural groove

5

the superior edges of the neural folds come together to turn the neural groove into this

neural tube

6

What does the neural tube do shortly after it forms?

detaches from the ectoderm and sinks to a deeper position

7

small groups of neural fold cells migrate between the surface ectoderm and the neural tube to form this

neural crest

8

What will the cells of the neural crest eventually become?

ganglia

9

Give the simple and the complex name for the three primary brain vesicles

1. prosencephalon - forebrain
2. mesencephalon - midbrain
3. rhombencephalon - hindbrain

10

meaning of encephalo

brain

11

swellings of the anterior end of the neural tube

primary brain vesicles

12

what the primary brain vesicles divide to become

secondary brain vesicles

13

What does the forebrain divide into?

telencephalon - endbrain
diencephalon - interbrain

14

What does the hindbrain divide into?

metencephalon - afterbrain
mesencephalon - spinal brain

15

What does the telencephalon become

cerebral hemispheres

16

What 4 things does the diencephalon form?

1. thalamus
2. hypothalamus
3. epithalamus
4. retina

17

What does the metencephalon divide to form?

1. pons
2. cerebellum

18

What does the myelencephalon form?

medulla oblongata

19

What three structures are considered the brain stem?

1. midbrain
2. pons
3. medulla oblongata

20

What does the mesencephalon become?

midbrain

21

What does the cavity of the neural tube enlarge to form?

brain ventricles

22

Why does the brain need to flex and fold?

not enough room in the skull

23

What are the two major flexures?

midbrain flexure
cervical flexure

24

What are the foldings of the cerebral surface called? What is their purpose?

convolutions - increase SA for more neurons

25

What is the outer layer of gray matter on both the cerebrum and cerebellum?

cortex -

26

What happens to the gray and white matter as you proceed down the spinal cord?

switch places - spinal cord has gray interior and white exterior

27

What fills the brain ventricles?

CSF - cerebrospinal fluid

28

What lines the brain ventricles and circulates the CSF?

ependymal cells (neuroglia)

29

What are the paired C shaped cavities that fill the cerebral hemispheres?

lateral ventricles

30

What thin membrane separates the anterior horns of the lateral ventricles?

septum pellucidum

31

What connects the lateral ventricles to the third ventricle?

interventricular foramina

32

Where is the third ventricle?

diencephalon

33

What connects the third and fourth ventricles?

cerebral aqueduct

34

Where is the cerebral aqueduct?

midbrain

35

Where is the fourth ventricle?

dorsal to the pons and superior medulla

36

What cavity runs through the spinal cord and connects to the fourth ventricle?

central canal

37

What are the openings in the fourth ventricle that connect to the subarachnoid space around the brain?

2 lateral apertures and a median aperture

38

What portion of the brain accounts for 83% of the total brain mass?

cerebral hemispheres

39

What are the ridges on the cerebral surface?

gyri/gyrus

40

What are the shallow grooves on the cerebral surface?

sulci/sulcus

41

What are the deep grooves on the brain surface?

fissures

42

What fissure separates the cerebral hemispheres?

longitudinal fissure

43

What fissure separates the cerebral hemispheres from the cerebellum?

transverse cerebral fissure

44

What are the 5 major lobes of the brain?

frontal
temporal
parietal
occipital
insula

45

What sulcus separates the frontal and parietal lobes?

central sulcus

46

What gyrus is in front of the central sulcus? What is its function?

precentral gyrus - primary motor cortex

47

What gyrus is behind the central sulcus? What is its function?

postcentral gyrus - primary somatosensory cortex

48

What sulcus separates the parietal and occipital lobes?

parieto-occipital sulcus

49

What sulcus separates the parietal and frontal lobes?

lateral sulcus

50

What lobe is an "island" of cortex hidden beneath the temporal, parietal, and frontal lobes?

insula

51

What are the pieces of gray matter buried inside the white matter of the brain? (2 terms)

basal nuclei (or historically basal ganglia)

52

the depressions in the skull where the brain fits - name the three, and say what part of the brain is in each.

cranial fossa
1. anterior - frontal lobes
2. middle - temporal
3. posterior - brain stem and cerebellum

53

What is gray matter? How thick is it? What do the convolutions do for it?

neuron cell bodies dendrites, glia, and blood vessels - 2-4mm - surface area is tripled by convolutions

54

What is white matter? What is its function?

myelinated axons bundled into tracts - that communicate between different parts of the brain

55

What type of imaging technique allows us to see maximal metabolic activity of the brain?

PET scan

56

What type of imaging technique shows blood flow in the brain?

functional MRI

57

In general, which hemisphere controls the sensory and motor functions of which side of the body?

opposite - contralateral

58

What is the term for the understanding that the two hemispheres are specialized for certain functions?

lateralization

59

Do the functional areas of the brain work independently of one another? Explain.

NO! Most conscious behavior involves the entire cortex

60

What are the large neurons in the primary motor cortex? What are their descending tracts called? (2 terms)

pyramidal cells - form pyramidal tracts also called corticospinal tracts

61

the representation of the entire body as a "little man" on the primary motor cortex
- the same thing on the primary somatosensory cortex

motor homunculi
somatosensory homunculi

62

mapping of the body in CNS structures

somatotopy

63

Where is the premotor cortex, and what is it responsible for?

anterior to the primary motor cortex - learned, repetitious motor skills and planning movements

64

the motor speech area is called what? Where is it located? What does it do?

Broca's area - anterior to the premotor cortex - controls speech planning and production

65

What is unusual about Broca's area?

usually only on one side of brain

66

Where is the frontal eye field, and what does it do?

above Broca's area - controls voluntary eye movements

67

What is the term for the ability of a person to discriminate what portion of the body is being stimulated?

spatial discrimination

68

What two portions of the somatosensory homunculus are represented by the largest areas?

lips and fingertips

69

Where is the somatosensory association area, and what is its function?

just posterior to the primary somatosensory cortex - to integrate sensory information and understand what you are sensing

70

Where is the primary visual cortex, and what is its function?

extreme tip of occipital lobe (calcarine sulcus) - sight

71

Where is the visual association area, and what is its function

surrounding the primary visual cortex - recognize what is seen

72

Where is the primary auditory cortex, and what is its function?

superior margin of temporal lobe - hearing

73

Where is the auditory association area, and what is its function?

posterior to the primary auditory cortex - interpret sounds

74

Where is the olfactory cortex, and what is its function?

medial part of temporal lobe called the piriform lobe - smell

75

What is the olfactory cortex part of?

rhinencephalon (primitive brain)

76

Through evolution, the new functions of the rhinencephalon include what? What do we call this system?

memory and emotions - limbic system

77

Where is the gustatory cortex, and what is its function?

insula - taste

78

Where is the visceral sensory area, and what is its function?

insula - posterior to taste region - sense organs (full or upset stomach, full bladder...)

79

Where is the vestibular cortex, and what is its function?

posterior part of insula and adjacent parietal lobe - equilibrium

80

What do we call areas that receive input from multiple senses and send outputs to multiple areas?

multimodal association areas

81

What is the purpose of multimodal association areas?

give meaning, tie to previous experience, store as a memory

82

What are the three parts of the multimodal association areas, and what is the function of each?

1. anterior association area - also known as the prefrontal cortex - most complicated region - intellect, cognition, recall and personality
2. posterior association area - recognizing patterns and faces, locating us in space, and making a coherent whole of our senses
3. limbic association area - emotions and memory

83

What are the parts of the limbic association area?

cingulate gyrus, parahippocampal gyrus, and hippocampus

84

Which of the multimodal association areas is the last to develop, and what is the significance of this?

prefrontal cortex - abstract ideas, judgment, reasoning, persistence and planning all develop slowly and depend on feedback from the social environment

85

What happens with tumors or lesions in the anterior association area?

mental and personality disorders - loss of normal social restraints

86

What happens with tumors or lesions in the posterior association area?

won't wash or dress part of body because don't recognize it as self

87

What does the term cerebral dominance refer to?

the side dominant for language

88

In 90% of people, what does the left brain control?

language, math and logic

89

In 90% of people, what does the right brain control?

creativity, intuition, emotion

90

Most people with left cerebral dominance dominantly use what hand?

right

91

a reading disorder where otherwise intelligent people reverse letters and words - How is it related to cerebral dominance?

dyslexia - thought to be a processing disorder in one hemisphere

92

What are the three types of white matter tracts in the brain, and what is their function?

1. commissural - connect corresponding gray areas of the two hemispheres for coordinated function
2. association fibers - connect different parts of the same hemisphere (short and long)
3. projection fibers - tie the cortex to the rest of the nervous system - ascending and descending

93

What is the largest commissure?

corpus callosum

94

projection fibers that form a compact band of white matter tracts between the thalamus and some of the basal nuclei - what are the fibers called as they radiate out to the cortex?

internal capsule - corona radiata

95

Name the 3 major bodies that make up the basal nuclei. What are they all called together? Why are they called this?

caudate nucleus, globus pallidus, and putamen - corpus striatum (look striped)

96

The putamen and globus pallidus are collectively called what?

lentiform nucleus

97

What is the function of the basal nuclei?

unsure - regulate attention and cognition, start and stop movements, monitor movement intensity

98

Disorders of the basal nuclei controlling movement are linked to what two diseases?

Parkinson's and Huntington's

99

What is the thalamus? What is the function of the thalamus?

a collection of specialized nuclei - relay station for information coming in to the cerebral cortex - sorts, edits, and groups similar

100

Where is the hypothalamus, and what are its functions (7)?

below the thalamus - contains many nuclei that serve to control the viscera
1. autonomic control center
2. center for emotional responses - limbic system
3. body temperature control
4. regulates food intake
5. regulates water balance and thirst - antidiuretic hormone
6. regulates sleep/wake cycles - suprachiasmatic nucleus
7. controls the endocrine system by controlling the anterior pituitary

101

What are the tiny, paired nuclei that extend from the hypothalamus, and what is their function?

mammillary bodies - olfactory relay station

102

What important gland connects to the hypothalamus? What is the stalk of tissue connecting the two structures?

pituitary - infundibulum

103

What happens when the pituitary doesn't function?

body wasting/obesity, sleep disorders, dehydration, emotional imbalances, failure to thrive

104

Where is the epithalamus?

most dorsal part of diencephalon

105

What is the gland that extends from the back of the epithalamus, and what does it do?

pineal gland - secretes melatonin

106

What is the function of melatonin?

induce sleep and antioxidant

107

The brain stem is similar histologically to the spinal cord with what major exception?

gray matter nuclei embedded in white matter

108

What is the function of the brain stem?

survival functions
10 or 12 cranial nerves root here

109

What does the term peduncle mean? What are the cerebral peduncles?

little feet - two vertical columns of white matter tracts above the pons

110

What is the corpora quadrigemina? How does the corpora quadrigemina get its name?

nuclei that protrude from the dorsal midbrain - 4 domes - quadruplets

111

What is the periaqueductal gray matter, and what is its function?

gray matter around cerebral aqueduct - pain suppression, link between fear perceiving area (amygdala) and fight or flight response, contains nuclei for oculomotor and trochlear nerves

112

What is the fear-perceiving center called?

amygdala

113

What are the parts of the quadrigemina and their functions?

superior colliculi - visual reflex center for tracking
inferior colliculi - auditory relay and startle reflex

114

What is the substantia nigra? Where is it located? What is its function?

nuclei in side of midbrain - makes dopamine

115

Why is the substantia nigra so dark?

accumulated melanin

116

What is the purpose of the melanin in the substantia nigra?

precursor to dopamine production

117

What is the ultimate cause of Parkinson's disease?

degeneration of dopamine producing neurons in substantia nigra

118

What is the red nucleus? Where is it located? What is its function?

gray matter deep to substantia nigra in the reticular formation that function as a relay for some motor neurons

119

Why is the red nucleus red?

blood supply and iron pigment

120

What is the meaning of the word pons? Why does it have this name?

bridge - conduction tracts between midbrain and medulla

121

What are the numerous nuclei in the pons called, and what is their function?

pontine nuclei - connect motor cortex and cerebellum, serve as part of reticular formation, maintain normal breathing rhythm

122

the middle portion of the brain stem, anterior bulge

pons

123

the most inferior part of the brain stem

medulla oblongata

124

What are the longitudinal ridges on the medulla called? What is their function?

pyramids - corticospinal tracts (descending)

125

the crossing of the corticospinal tracts or pyramids at the junction between the medulla and spinal cord - What does this explain?

decussation of the pyramids - explains why right side of brain controls left side of body and left brain controls right body

126

oval swellings lateral to the pyramids that contain nuclei that relay sensory information about the stretch of muscles and joints

olives

127

a measure of the electrical activity of the brain using electrodes

EEG - electroencephalogram

128

patterns of electrical activity in an EEG

brain waves

129

What generates brain waves?

synaptic activity

130

How are brain waves measured?

Hertz - Hz

131

What is a Hertz?

1 wave or cycle per second

132

What is amplitude?

the height of a wave or the depth of a trough

133

Name, and describe the four major patterns of brain waves.

1. alpha - 80=-13 HZ, regular and rhythmic, low amplitude, calm and relaxed state of wakefulness
2. beta - 14-30 Hz, rhythmic but not as regular, higher frequency, mentally alert and concentrating
3. theta - 4-7 Hz, irregular, common in children, uncommon in awake adults
4. delta - 4HZ or less, high amplitude, deep sleep, under anesthesia, may indicate brain damage in awake adults

134

brain waves that are 4HZ or less, high amplitude, deep sleep, under anesthesia, may indicate brain damage in awake adults

delta

135

brain waves that are 80=-13 HZ, regular and rhythmic, low amplitude, calm and relaxed state of wakefulness

alpha

136

brain waves that are 14-30 Hz, rhythmic but not as regular, higher frequency, mentally alert and concentrating

beta

137

brain waves that are 4-7 Hz, irregular, common in children, uncommon in awake adults

theta

138

What four factors can change brain waves?

age, stimulation, disease, chemical state

139

What are EEGs useful at diagnosing?

epilepsy, sleep disorders, brain function

140

a flat EEG is clinical evidence of what?

brain death

141

a flood of electrical activity that interferes with brain function

epilepsy - seizure

142

List 5 things that can cause seizures.

trauma, stroke, infection, high fever, tumors, genetic factors

143

What are the two main kinds, and how are they different?

1. absence (petit mal) - goes blank for a few seconds where not everyone will notice
2. tonic-clonic (Grand mal) - intense convulsions

144

What sometimes precedes a seizure, and how can it be helpful?

aura - light, smell, or taste hallucination that allows the person to lie down

145

What is a difference after the absence or tonic-clonic seizures?

tonic clonic seizures leave the person disoriented

146

What can control epilepsy?

anticonvulsive drugs or vagus nerve stimulator

147

What 3 factors indicate consciousness?

1. ability to initiate movement
2. perception of sensation
3. higher mental functioning

148

What are the 4 degrees of consciousness?

1. alert
2. drowsy (lethargy)
3. stupor
4. coma

149

a brief loss of consciousness (2 terms)

fainting or syncope

150

How is sleep different from a coma?

Sleeping people use almost as much oxygen as people who are awake, and they can be aroused by stimulation.

151

Give 5 things that can cause a coma.

1. blow to the head
2. tumor
3. infection
4. metabolic disturbance - hypoglycemia
5, overdose
6. liver or kidney failure

152

What are the two major types of sleep?

REM and non-REM

153

What happens during the first part of our sleep?

brain waves decline, respiration, blood pressure and heart rate decline

154

What happens when we are in REM sleep?

alpha waves appear, digestion is inhibited, BP, respiratory rate,and heart rate increase, use more oxygen than when awake, dream

155

When do most nightmares and night terrors happen?

NREM stages 3-4

156

our alternating sleep and wake cycles reflect a natural 24 hour cycle called what?

circadian rhythm