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Flashcards in Unit 7 Deck (127):
1

Secondary embryonic vesicle from the proseencephalon

- Diencephalon

2

What does diencephalon mean?

- "Between brain"
- Actually means between the great cerebral hemispheres

3

Major parts of the diencephalon

- 3rd ventricle
- Epithalamus
- Thalamus (included metathalamus)
- Hypothalamus (under thalamus)
- Subthalamus (ventral thalamus)

4

Where is the choroid plexus?

- 3rd ventricle (CSF secretion)

5

Where are the medial and lateral geniculate bodies?

- Metathalamus of the Thalamus

6

Functions of the diencephalon

- Most significant relay center for sensory input to the cerebellum (all sensations except olfaction)
- Integrative as well as relay
- Significant center for control of autonomic and endocrine functions

7

Just superior to the midbrain tectum

- Epithalamus

8

Structures included in the Epithalamus

- Pineal gland
- Posterior commissure

9

Also known as the "Epiphysis Cerebri"

- Pineal gland (body)

10

"Brain sand"

- Calcifications of the pineal gland accumulating with age

11

Built like an endocrine gland, the pineal body secretes what?

- Melatonin
- Seratonin
- Norepinepherine

12

When is the secretion of neurotransmitters from the pineal gland active?

- Late night hours (2-4 AM)

13

The pineal body is not sensitve to light directly, but through what?

- A pathway originating in the retina and synapsing in the hypothalamus (specifically the suprachiasmic nucleus)

14

Melatonin levels appear to be a function of what?

- The circadial cycle (not the controller of the cycle)

15

Seasonal affective disorder (SAD) affects how many people in the U.S. and canada?

- 1 in 20

16

A small, but identifiable commissure just superior to the midbrain tectum

- Posterior commissure

17

What are located in the posterior commissure of the epithalamus?

- Pupillary light reflex fibers and nuclei

18

Just anterior and inferior to the posterior commissure is a small structure

- Subcommissural organ

19

What might the subcommissural organ do?

- Produce aldosterone

20

What is the subcommissural organ made primarily of?

- Ependymal cells

21

Included with the thalamus are the lateral and medial geniculate bodies, often classified separately as what?

- Metathalamus

22

The thalamus is composed of 2 ovoid masses of gray matter, joined together by a bridge of gray matter substace called what?

- Massa Intermedia (Interthalamic adhesion)

23

What is lateral to each thalamic mass?

- Posterior limb of the internal capsule

24

General functions of the thalamus

- All sensory input, except olfaction, is relayed here
- Helps focus the attention of the cerebral cortex
- Some appreciation of pain and pemperature sensations are interpreted here

25

The thalamus us divided into equal right and left thalamic masses held together by what?

- Massa Intermedia (MI)

26

Largest part of the thalamus; posteriorly located

- Pulvinar

27

What does the hypothalamus form?

- The floor for the 3rd ventricle
- Portions of the 3rd ventricles lateral walls

28

What is included as part of the hypothalamus' structure?

- Infundibular stalk
- Optic chiasma

29

Hypothalamus consists of what 2 zones?

- Medial
- Lateral

30

The medial zone of the hypothalamus is subdivided into what?

- Anterior
- Intermediate
- Posterior

31

Functions of the hypothalamus

- Vague control of the basic drives of hunger, thirst, and sex
- Controls physical aspects of emotional expressions
- Central control over autonomic functions

32

Parasympathetic control of the hypothalamus

- Anterior and intermediate areas
- Inc. digestive motility
- Dec. heart rate
- Constriction of the pupil

33

Sympathetic control of the hypothalamus

- Posterior area
- Inc. heart rate
- Vasoconstriction
- Dec. digestive motility
- Pupil dilation
- Piloerection
- Sweat gland secretion

34

Endocrine control from the hypothalamus

- Directly via neuron axon extensions into the posterior pituitary
- Indirectly via neurohormones to control the release of anterior pituitary hormones

35

The region of the hypothalamus superior and posterior to the optic chiasma and infundibular stalk is subdivided into 3 areas

- Anterior area
- Intermediate (central) area
- Posterior area

36

The area just above the optic chiasma

- Anterior area

37

Important nuclei in the anterior area

- Surpaoptic and Paraventricular nuclei
- Suprachiasmatic nuclei (SCN)
- Anterior nucleus
- Preoptic area (nucleus

38

This nucleus is responsible for much of our circadial 24 hour rhythms such as temperature, sleep, light, feeding, ect

- Suprachiasmatic Nuclei

39

The suprachiasmic nuclei is complexly connected to what?

- The pineal gland and its secretions into the bloodstream

40

Nucleus in the anterior area generally known for parasympathetic functions

- Anterior nucleus

41

Nucleus in the anterior area known to be a thermo-regulator; especially as the heat goes up

- Preoptic area (nucleus)

42

Nuclei in the intermediate area

- Dorsomedial nuclei
- Ventromedial nuclei
- Arcuate nuclei

43

Nuclei of the intermediate area that has significant GI tract parasympathetic influence

- Dorsomedial nuclei

44

Nuclei of the intermediate area which is a center for eating and thirst gratification

- Ventromedial nuclei

45

Nuclei of the intermediate area near the infundibular stalk that contributes axons to the tuberoinfundibular tract

- Arcuate nuclei

46

A term used to describe the undulating bulge between the infundibular stalk and the large mammillary bodies

- Tuber cinereum

47

Nuclei in the posterior area

- Mammillary bodies
- Posterior nuclei

48

Nucleus of the posterior area important for short term memory

- Mammillary bodies

49

Nucleus of the posterior area which is a thermoregulator; especially as the body cools down (shivering)

- Posterior nuclei

50

What is the posterior area known for?

- Diverse sympathetic actions

51

What does the posterior pituitary develop from embryologically?

- Diencephalon

52

Which area gives rise to the anterior and intermediate pituitary?

- Rathke's pouch

53

Most blood to the pituitary and infundibular stalk comes from branches off what?

- Internal carotid arteries

54

Within the infundibular stalk, the small arteries break into highly permeable capillaries called what?

- Fenestrated sinusoid

55

The fenestrated sinusoids do what?

- Picks up the "releasing factors" from the tuberoinfundibular tract fibers

56

A series of small veins drain the hormone-laden blood to the capillary beds of the ______

- Anterior pituitary

57

The veins that drain the hormone-laden blood to the capillary beds of the anterior pituitary are actually porting blood between two capillary beds are called what?

- Hypophyseal portal veins (and system)

58

Once the releasing factors enter the substance of the anterior pituitary they exert what?

- A controlling influence on the release of pituitary hormones

59

Locations of the subthalamus

-Just under the lateral ventral aspect of the thalamus

60

The subthalamus includes the following nuclei

- Parvocellular region of the red nucleus
- Superior portion of the substantia nigra
- Subthalamic nuclei (corpus Luysi)

61

Among other connections, the subthalamic nuclei sends and recieves fibers to and from what?

- The globus pallidus of the telecephalon

62

What system is the subthalamic nuclei part of?

- Extrapyramidal system

63

What may lesions of the subthalamic nucleus lead to?

- Usually vascular
- May lead to dramatic forceful flinging movements of the shoulders and/or hips
- This movement is called hemiballism or ballism

64

General characteristics of the telecephalon

- Anatomically: RIght and left hemispheres are equivalent
- Functionally: The 2 hemispheres have significant differences event hough most of the activity is eventually shared via commissural fibers

65

Parts of the telecephalon

- Pallium
- Centrum semiovale
- Basal ganglia

66

Outer convoluted gray cerebral cortex of the telecephalon

- Pallium

67

An underlying mass of white fibers of the telecephalon collectively called...

- Centrum semiovale

68

Deep within the white matter are collections of neuron cell bodies in the telecephalon

- Basal ganglia (nuclei)

69

Lobes on each side of the telecephalon

- Frontal lobe: Largest
- Temporal lobe
- Parietal lobe
- Occipital lobe (smallest)

70

Functions of the telecephalon

- Final integration of neural machanisms
- Initiation center for voluntary actions
- Memory and associative memory
- Abstract thinking: serves as basis for much of our emotional response

71

Total surface area of the pallium (cerebral cortex)

- About 2.5 square feet

72

Where is 2/3s of the surface of the pallium (cerebral cortex?

- Down in the sulci

73

What is the thickness of the pallium (cerebral cortex)?

- 1.5-4.5 mm

74

In most areas of the pallium, what is thicker, the gyrus cortex or the sulcus cortex?

- Gyrus cortex

75

What is the total number of neurons in the cerebral cortex?

- 50-60 billion

76

Each neuron of the pallium (cerebral cortex) may synapse with an average of how many other neurons? As high as how many neurons?

- Average: 600
- As high as: 4,000

77

Subdivisions of the pallium (cerebral cortex)

- Neocortex (isocortex)
- Allocortex

78

Subdivision of the pallium (cerebral cortex) which is phylogenetically new and occupies 90% of the total cerebral cortex

- Neocortex (isocortex)

79

Subdivision of the pallium (cerebral cortex) which includes 2 ancient parts that occupies about 10% of the total cerebral cortex area

- Allocortex

80

6 common laminae of the neocortex

- Molecular lamina I
- External granular lamina II
- External pyramidal lamina III
- Internal granular lamina IV
- Internal pyramidal lamina V
- Multiform lamina VI

81

Molecular layer (lamina I)

- The outermost lamina and nearest to the pia mater
- Filled with synaptic activity

82

External granular layer (lamina II)

- Small closely packed granular neurons
- Axons extend into deeper lamina of the same cortex area

83

External pyramidal layer (lamina III)

- Small pyramidal-shaped neurons
- Axons extend out of the cortex to the white matter and then returns to the gray matter

84

What are laminae II and III all called?

- Associative lamina
- Best developed in the human brain

85

Internal granular layer (lamina IV)

- Small closely packed cell bodies
- The specific thalamic inputs arrive here
- Well developed in sensory areas

86

Internal pyramidal layer (lamina V)

- Large pyramidal-shaped neuron cell bodies here
- Giant pyramidal (Betz) cells are found here in certain areas
- Axons "project" to other brain and cord centers from here

87

Multiform layer (lamina VI)

- A mix of incoming and outgoing fibers
- Has a large number of "projection" neurons

88

What are laminae V and VI are sometimes called?

- Projection laminae

89

Loss of power to communicate through writing, speaking or signs

- Aphasia

90

Inability to recognize faces

- Prosopagnosia

91

Functions of the telecephalon typically lateralized to the left

- Speech
- Linear reasoning
- Grammar
- Vocabulary
- Tool use

92

Functions of the telecephalon typically lateralized to the right

- Spatial manipulations
- Prosodic language: Facial expressions
- Intonation
- Singing

93

Parts of the basal ganglia

- Caudate nucleus
- Putamen nucleus
- Globus pallidus (paleostriatum
- Amygdaloid complex (archistriatum)

94

Where do the caudate nucleus and the putamen nucleus run?

- Neostriatum --> corpus striatum --> basal ganglia

95

Where does the globus pallidus run?

- Corpus striatum --> basal ganglia

96

Where does the amygdaloid complex run?

- Basal ganglia

97

What are the putamen and globus pallidus together called?

- Lenticular nucleus (lentiform)

98

What does striatal lesions of the basal ganglia normally lead to?

- Dyskinesia (muscle tone distubances)

99

What does dyskinesia include?

- Tremors
- Chorea
- Hemiballism (ballism)

100

Example of a tremor

- Parkinsonism

101

Chorea

- Results in a brisk series of graceful involuntary movements of extremities, facial muscles, tongue, ect
- Corpus striatum begins to deteriorate
- Genetic deficiency of GABA

102

Hemiballism

- More violent movement
- Can also occur from lesions in the globus pallidus

103

Parts of the caudate nucleus

- Head
- Body
- Tail

104

What is the head region of the caudate nucleus continuous with?

- Putamen nucleus by gray matter bridges

105

Afferent fibers synapse in the caudate from where?

- All lobes of the cortex, thalamus, substantia nigra, and putamen

106

Efferent output fibers extends from the caudate to where?

- Putamen, globus pallidus, substantia nigra and the thalamus

107

Most lateral of the corpus striatal nuclei

- Putamen nucleus (neostriatum)

108

Afferent fibers synapse in the putamen from where?

- Same as caudate
- Caudate also sends fibers to the putamen

109

Efferent fibers extends from the putamen from where?

- Same as caudate

110

Parts of the lenticular nucleus

- Globus pallidus nucleus
- Putamen nucleus

111

Separates the globus pallidus into medial and lateral segments

- Medial medually lamina

112

Separates the lateral part of the globus pallidus from the putamen

- Lateral medullary lamina

113

Cell appearance of the globus pallidus

- Much different than from the caudate and putamen

114

Afferents (also called pallidal fibers) include axons from the:

- Caudate nucleus
- Putamen nucleus
- Subthalamic nucleus

115

Efferent (often called pallidalfugal fibers) represents what?

- The primary efferent outflow from the corpus striatum

116

What does the basal ganglia play a key role in?

- The extrapyramidal system
- Some would call it a pre-upper motor influence

117

Name given to the collective white matter of the telecephalon

- Centrum semiovale

118

Fiber types in the white matter of the telencephalon

- Projection axons
- Commissural axons
- Association axon bundles (fasciculi)

119

Where do most projection axons of the telencephalon travel in?

- Corona radiata
- Internal capsule

120

Where are commissural axons of the telecephalon found?

- In the corpus callosum

121

Parts of the corpus callosum

- Splenium
- Body
- Genu
- Rostrum
- Forceps anticus
- Forceps posticus
- Tapetum

122

Lesions and surgery on the corpus callosum

- Alien hand syndrome
- Extreme seizures

123

The most abundant part of the white matter in the telecephalon

- Association axon bundles (fasciculi)

124

Types of the association axon bundles (fasciculi)

- Short fibers
- Long fibers

125

Association axon bundles that connects adjacent or near gyri, just inward from the gray cortex

- Short fibers

126

Association axon bundles that connects distal parts of the same hemisphere

- Long fibers

127

Dementia pugilistica

- Repeated head trauma
- Diffuse damage involving cerebellum and corpus callosum
- Increase ventricular size