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0

What is brain size proportional to?

Body size only and can be divided into three major portions

1

What 3 major portions can the brain be divided into?

1. Cerebrum
2. Cerebellum
3. Brainstem

2

Cerebrum appearance

-83% of brain volume
-consists of 2 cerebral hemispheres
-divided into multiple lobes each marked by gyri and sulcus

3

Sulcus

shallow groves (slits)

4

Fissure

DEEP groves (deep slits)

5

Gyrus

Convolutions (ridges that stick out)

6

Longitudinal fissure

Separates the left and right hemispheres, although they remain connected through the corpus callosum

7

Central sulcus

Separate front and back of cerebrum

8

Cerebellum location

Lies inferior and posterior to the cerebrum; more delicate surface markings
(Below and to the back of cerebrum)

9

Brainstem parts

Base of brain
Thalamus
Hypothalamus
Midbrain (top of brains stem/middle of brain)
Pons (bump)
Medulla oblongata (slight bump)

10

Cerebrospinal fluid location

Make in ventricles (lined with epithelium- ependemial cells)
-fills 4 hollow spaces in brain

11

Gray matter

Consisting of non-myelinated soma and dendrites

12

White matter

Myelinate nerve fibers (myelin is on axon)

13

**Location of gray matter in brain and spinal cord

Gray matter forms outer cortex* in brain, but is an inner core* in the spinal cord

14

White matter location in brain and spinal cord

White matter is inside brain and outside spinal cord

15

Meningitis

Very courageous and very deadly inflammation/infection in brain. Perform spinal tap to detect

16

Meninges

(Singular=meninx)
3 protective fibrous coverings that separate the brain and spinal cord from the skull and vertebrae

17

What separates brain and spinal cord from the skull and vertebrae

Meninges

18

Dura mater

Outermost meninx, really rough, consists of a periosteal layer and an inner meningeal layer

19

What part of and what does the dura mater form within the vertebral canal?

The meningeal layer (inner layer of dura mater) forms a dural sheath

20

Dural sheath

Same thing as the meningeal layer (inner layer) of the dura mater just the name for when it's in the vertebral canal!

21

Epidural space location

Between the dural sheath and surrounding bone

(Space is between the skull and the dura mater)

22

Arachnoid mater

The second meninx that adheres to the dura and sends spider like extensions out to the #3 pia mater (highly vascular)

23

#3 pia mater

Highly vascular, closely follows the contour of the brain

24

Subdural space

Between (below) dura mater and (above) arachnoid mater

25

Subarachnoid space

Separates arachnoid and pia mater

26

Cerebrospinal fluid appearance and function

Clear, colorless liquid that functions to lend buoyancy, for protection, in waste removal, and in providing a stable chemical environment

27

What is CSF produced by

The choroid plexus (area with ependymal cells) within each of the 4 ventricles

28

What do the ventricles in brain consist of?

Capillaries covered by simple cuboidal epithelium (ependymal cells that make CSF)

29

Blood-CSF fluid barrier

Tight junctions within capillaries in the choroid plexus form this that protects the brain; regulates substance entering the brain

30

Lateral ventricle

(2) located in each cerebral hemisphere; communicates with a third ventricle through an inter ventricular foramen

31

Interventricular foramen

How 2 lateral ventricles in each cerebral hemisphere communicate with a third ventricle

32

Cerebral aqueduct

Connects the third ventricle with the fourth ventricle

33

Circulation of CSF

Originated in choroid plexus, circulated through ventricles, makes its way into central canal of spinal cord, exits the fourth ventricle through two apertures (openings)

34

Does spinal cord go whole length of vertebrae?

NOOOO

35

Hydrocephalus

Hydro=water
Cephalus= head
"Water on the brain"- results from blockage of the route of CSF and its absorption
-causes- injury, rumors, infections, etc.

36

What fills up in hydrocephalus

The ventricles causing pressure and displacement

37

Blood supply in brain

Very metabolically active (demand for oxygen and glucose). Stopping blood supply for as little as 4 minutes can cause irreversible damage!!

38

Where is the blood-brain barrier NOT located?

It's absent in areas of the brain (called circumventricular organs) that monitor blood glucose, pH, salinity, etc.

39

Circumventricular organs

Circum= around
Ventricular= ventricles
Monitor blood glucose, pH, salinity etc. Blood-brain barriers absent here **

40

3 functions of spinal cord

Locomotion, conduction, and reflex activity control

41

Where does the spinal cord begin and end?

Begins at the foramen magnum and ends and the FIRST lumbar vertebrae

42

How many pairs of spinal nerves are there?

31 pairs

43

How many cranial nerves are there

12 pairs

44

where does the spinal cord enlarge?

Cervical and lumbar areas; nerves to the appendages arise

45

Conus medullaris

Cord tapers to a point and end

46

Cauda equina

Nerve bundle exits the bottom of spinal cord (nerve fibers coming off conus medullaris)

*cauda-caudal-tail

47

Filum terminale

In addition to cauda equina

48

Lumbar puncture

Between vertebrae through fibrocartilage, punctures dura mater to get fluid; gives idea of what's going on in brain

49

Fissure and sulcus in spinal cord cross section

Anterior median fissure (deep) and posterior median sulcus (not so deep)

50

Horns of spinal cord

Divided regions of a central area of gray matter in the spinal cord; 2 dorsal or posterior horns and 2 ventral or anterior horns

51

Gray commissure

Connects the right and left halves of horns in spinal cord

52

Central canal

Center of central gray matter (horns) in spinal cord

53

Route of sensory fibers **

Enter dorsal horn, synapse with an interneuron and somatic motor neurons exit via the central root of the spinal nerve.

54

How do nerves come out of spinal cord

In pairs (two roots)

55

Are tracts white or gray matter?

White matter
They are axons !!!

56

Ascending tracts

Spinal tracts that carry sensory information UP the spinal cord

57

Descending tracts

Spinal tracts that carry motor information DOWN the spinal cord

58

Decussation

a crossed tract of nerve fibers passing between centers on opposite sides of the nervous system

Left/right, right/left

59

What is the most important part of the brain?

Medulla oblongata

60

What does the medulla oblongata (hindbrain)control?

Coughing, hiccuping, sneezing, sweating, vomiting etc.

61

What 3 centers are in the medulla oblongata (hindbrain)

Cardiac, vasomotor, and respiratory centers

62

Hindbrain

Consists of the cerebellum, pons, and medulla oblongata

(Brain stem)

63

How does info get from the cerebrum to the cerebellum

Must go through pons

64

What does the pons (hindbrain) control

The gray matter of the pons contains nuclei (gray matter masses) concerned with sleep, posture, respiration, swallowing, and bladder control.

65

Nuclei in brain

Little areas of gray in inside (gray is usually outside of brain)

66

Cerebellum physical features

Largest of the hindbrain !!
Right and left cerebellar hemispheres connect via the vermis; three paired cerebellar peduncles (nerve tracts) connect the cerebellum to the brainstem

67

What connect he cerebellum (hindbrain) to the brainstem

3 paired peduncles (nerve tracts)

68

Peduncles

3 paired peduncles= nerve tracts that connect the cerebellum to the brainstem

69

What does the cerebellum (hindbrain) control?

Modulates and coordinates VOLUNTARY movement of the limbs, maintains muscle tone and posture, coordinated eye movements, and helps in learning motor skills

70

Tectum

Midbrain!
Consists of 4 nuclei called the corpora quadrigemina

71

What does the tectum (mid-brain) control

The corpora quadrigemina of the tectum function in visual attention, tracking objects, and visual reflexes

72

Reticular formation location

A group of 100 nuclei scattered throughout the medulla, midbrain, and pons

73

What does the reticular formation do?

Function in somatic motor control, autonomic control, arousal, and pain modulation.

74

What does the thalamus consist of (top of brain stem)

Two oval masses of gray matter, underneath each cerebral hemisphere

75

Function of the thalamus (top of brain stem)

It's the gateway to the cerebral cortex, nearly all info heading to the cerebrum passes through the thalamus, EXCEPT for sensory input from smell

76

What is the one thing that does not pass through the thalamus?

Sensory input from smell

77

What does the hypothalamus (brains stem) control

Major control center for ANS and endocrine; also homeostasis (involuntary and hormones)

78

Function of nuclei

(Gray covered by white)
Regulate food-water intake, thermoregulation, cardiovascular (medulla oblongata) regulation, sleep/waking, emotions

79

Epithalamus function

cone-shaped gland, best known for synthesis of melatonin from serotonin. Role in light-sensitive circadian rhythms

80

Melatonin

Influence on sleep; regulates time clock (nightly sleep cycle)

81

Cerebral white

The white matter of the cerebrum does NOT make decisions, but comprises most of the cerebral volume

82

Cerebral cortex anatomy

(40% of brain mass) a layer of gray matter (2-3mm thick) covering the cerebral hemispheres

83

What are the 4 lines regions of the cerebral cortex

Frontal, parietal, occipital, and temporal

84

Basal nuclei

Masses of gray matter buried deep in the cerebral hemispheres, involved in motor control and some thought process

85

Limbic system

A loop of cortical structures surrounding the corpus callosum and thalamus
PERSONALITY AND EMOTIONS

86

What emotions are controlled by limbic system

Fear, anger, love, and others

87

Brain waves

Rhythmic voltage changes resulting from synchronized postsynaptic potentials in the cerebral cortex

88

How can brain waves be recorded

As as electroencephalogram (EEG); often used as a legal criteria for death

89

Sleep

A temporary state of unconsciousness (can be aroused)

90

Coma

Person cannot be aroused

91

What in the brain controls sleep

Hypothalamus and brain stem

92

How many stages of sleep are there

4
The 4th stage is deep (slow wave)

93

What happens during sleep several times a night?

Person backtracks to stage 1 and enters REM sleep

94

Rapid eye movement (REM) sleep

Enter several times a night, also called paradoxical sleep because of the difficulty with which a sleeper can be aroused. Most dreams occur during this period. As sleep continues periods of REM get longer

95

What happens during REM and what happens to it as sleep continues

Dreams and periods of REM sleep get longer as sleep continues

96

Insomnia
Symptoms and percent of population

Inability to fall or remain asleep
10%

97

Narcolepsy

Abnormal REM sleep causes extreme daytime sleepiness, behind between ages 15 and 25.
0.02-0.06%

98

Obstructive sleep apnea syndrome

Upper airway collapses repeatedly during sleep, blocking breathing. Snoring and daytime sleepiness
4-5%

99

Parasomnias

Sleepwalking, sleep talking, and night terrors outgrown less than 5% children

100

Restless leg syndrome

Brief, repetitive leg jerks during sleep. Leg pain forces person to get up several times a night

Very rare

101

7 functions of the cerebral cortex

Motor control, somatic control, special senses, association areas, cerebral lateralization, language, and memory

102

Motor control

(Cerebral cortex)
Volunteers muscle contractions are initiated in the motor association area of the frontal lobes. The impulse is then sent to the precentral (front) of the gyrus (primary motor area)

103

Somatic control

(Cerebral cortex)
The postcentral gyrus functions as the primary sensory area. Here neurons receive sensory info. (Receive sensory info in back)

104

Special senses

(Cerebral cortex)
Input from the special senses (light, hearing, etc) does NOT enter the postcentral gyrus but instead travels to other specialized areas of the brain

105

Association areas

(Cerebral cortex)
Carious association areas are located in the cerebral cortex including the somatosensory association area, the visual association area, the auditory association area, and the front association area.

106

Cerebral lateralization

(Cerebral cortex)
The assignment of different tasks to different hemispheres, and is correlated with handedness. Most Americans are right handed (left hemisphere). Males show more lateralization.

107

Language

(Cerebral cortex)
Includes several abilities and is assigned to different regions of the cerebral cortex

108

Memory

(Cerebral cortex)
The storage and retrieval of acquired info or skills; established in phases

109

Short term memory

(Cerebral cortex)
Lasts up to a few hours and is limited to 7-12 bits of info

110

Long-term memory

(Cerebral cortex)
Last longer and can store an unlimited amount of info

111

Positron emission tomography (PET)

Shows both blood flow and metabolism (of oxygen and glucose) in the tissues of the working brain (sees how active the brain is)

112

Magnetic resonance imaging (MRI)

Uses magnetic fields and radio waves to produce high quality images of brain structures (better than CT in analyzing the nervous system and other soft tissue)

113

Cranial nerve name and function

I

Olefactory

Smell

114

Cranial nerve name and function

II

Optic
Vision

115

Cranial nerve name and function

III

Oculomotor
Eyelid and eyeball movement

116

Cranial nerve name and function

IV

Trochlear
Innervates superior oblique and turns eye downward and laterally

117

Cranial nerve name and function

V

Trigeminal
Chewing, face and mouth touch and pain

118

Cranial nerve name and function

VI

Abducens
Turns eye laterally

119

Cranial nerve name and function

VII

Facial
Controls most facial expressions, secretion of tears and saliva taste

120

Cranial nerve name and function

VIII

Vestibulocochlear (auditory)
Hearing; equilibrium sensation

121

Cranial nerve name and function

IX

Glossopharyngeal
Taste; sense carotid blood pressure

122

Cranial nerve name and function

X

Vagus
Senses aortic blood pressure, slows heart rate, stimulates digestive organs, taste

123

Cranial nerve name and function

XI

Spinal accessory
Controls trapezius and sternocleidomastoid, controls swallowing movements

124

Cranial nerve name and function

XII

Hypoglossal
Controls tongue movements

125

What are the two cranial nerves that take part in controlling taste?

X Vagus
and
VII facial

126

What 2 cranial nerves have to do with the heart and blood pressure

IX Glossopharyngeal
and
X vagus

127

What 4 cranial nerves have to do with eye movement

II Optic
III oculomotor
IV Trochlear
and
VI abducens

128

Frontal lobes

Motor areas- voluntary skeletal muscle

Association areas- high intellectual processing

129

Parietal lobes

Sensory areas- temp., touch, pressure, pain (skin)

Association areas- understanding speech and words to express thoughts and feelings

130

Temporal lobes

Sensory areas- hearing

Association areas- interpret sensory experiences and remember visual scenes, music, etc.

131

Occipital lobes

Sensory areas- vision

Association areas- combine visual images with other sensory experiences

132

How are fibers classified

Direction (afferent/efferent), types of organs they innervate (somatic/visceral) and distribution (general/local)

** S-A-M-E

133

Mixed nerves

Have BOTH motor and sensory fibers

134

Sensory nerves (Olfactory and optic) contain...

Mostly sensory fibers

135

Motor nerves contain ....

Motor fibers

136

Ganglion

Cluster of nerve cell bodies generally outside the CNS

137

Location of cranial nerves

(12 pairs)
Emerge from base of brain lead to muscles and sense organs in head and neck for most part

138

Are spinal and cranial nerves part of the CNS or ANS?

ANS NOT the CNS !!!

139

How does each spinal nerve branch?

Into dorsal root and ventral root

140

Dorsal root ganglion

Occupied by cell bodies from afferent neurons

141

Spinal nerve is formed by..

Convergence of dorsal and ventral roots

142

Cauda equina is formed by...

The roots arising from segments L2 to Cx of the spinal region

143

What does the spinal nerve do after emerging from the vertebral column

It divides into dorsal root and ventral root and a small meningeal branch that leads to the meninges and vertebral column

144

dorsal ramus

Innervates the muscles and joints of the spine and the skin of the back

145

Ventral ramus

Innervate a the ventral and lateral skin and muscles of the trunk, plus gives rise to nerves leading to the extremities

146

What spinal nerve receives sensory input from a specific area of the skin (dermatome)?

Every spinal nerve except C-1

147

How long do spinal nerves extend

From foramen magnum to 2nd lumbar vertebra

(End= conus medullaris)

148

What continues after conus medullaris and attaches to coccyx?

Pia mater as filum terminale

149

Spinal nerve extending downward from conus

cauda equina

150

What two groves extend the length of the spinal cord

Anterior medial fissure and posterior median sulcus

151

Somatic reflexes

Quick, involuntary, stereotypes reactions of peripheral effectors to stimulation.

152

What is a spinal reflex made up of?

Reflex arc including: Somatic receptors, afferent nerve fibers, interneurons (association neurons), efferent nerve fibers, and skeletal muscle

153

What happens when a muscle is stretched

It contracts to maintain tone (*stretch flex)

154

Tendon reflex

(Knee jerk)
An example of monosynaptic reflex arc.

155

Golgi tendon organs

Located at junction of a muscle and its tendon

156

What do Golgi tendon organs produce?

An inhibitory response called the Golgi tendon reflex when muscle contracts too tightly (prevents damage to tendon)

157

What is the peripheral nervous system a part of?

ANS

158

What are the two parts of the peripheral nervous system

Somatic (motor and sensory)
and autonomic (just motor)

159

Is the peripheral nervous system in the spinal cord?

NO outside of CNS

160

Somatic motor (efferent) divisions

Skeletal muscle, one efferent neuron, excitatory, acetylcholine (ONLY), voluntary

161

Autonomic divisions

Motor/efferent ONLY
Smooth muscle/cardiac muscle/glands (not endocrine), two efferent neurons, excitatory or inhibitory, post ganglionic, acetylcholine or norepinephrine, and involuntary

162

Can excitatory and inhibitory neurons go to same place?

Yea but stronger one wins or cancel each other out

163

What are the two efferent neurons in the autonomic peripheral nervous system

Pre ganglionic and post ganglionic

164

Pre ganglionic neuron

Dendrite + soma in CNS, axon exits
CNS proceeds to autonomic ganglion, always produces ACh!

165

Post-ganglionic neuron

Cell body WITHIN autonomic ganglion but refer to it as entirely in ANS. Produces ACh or Norepinephrine

166

What's the one exception with the 2 efferent neurons in the autonomic peripheral nervous system?

Usually 2 efferent neuron pathways found in ANS but there is NO post ganglionic neuron to the adrenal medulla (one 1 pre gang.)
---> direct route to adrenal medulla, NO connection to autonomic ganglion. ACh

167

Adrenal medulla gland

Above kidney, stimulated by norepinephrine; gland produces norepinephrine and 80% epinephrine, releases into blood can act as neurotransmitter

168

What are the two divisions of the ANS?

Sympathetic and parasympathetic

169

What division of ANS are most organs innervate by?

BOTH sympathetic and parasympathetic

170

Sympathetic

-Division of ANS
-EXCITATORY
-(Aka thoracolumbar)

171

Where are pre ganglionic neurons in sympathetic division of ANS

They exit the CNS from this region of the spinal cord (thoracolumbar)

172

What does the sympathetic division of the autonomic nervous system do for us?

Preparation for stressful situations ... "fight or flight system"

173

Do sympathetic and parasympathetic nervous systems combine?

Not usually bc they have opposite affects on cells/organs but they may both be active

174

Parasympathetic

-INHIBITORY
-craniosacral (head to tail)
-pre ganglionic neurons exit CNS from this region of the spinal cord

175

What does the parasympathetic nervous system do for us?

Returns body to normal conditions after stress
"Feed and breed"
"Resting and digesting"

176

What happens if both sympathetic and parasympathetic nervous systems are active?

The overall effect is influenced by the degree which one may predominate over the other and the particular nature of receptor sites

177

What is the result of the adrenal medulla exception to the sympathetic division of ANS?

Adrenal medulla releases its own norepinephrine, mostly epinephrine, which is carried via the blood stream to responsive receptor sites

178

What is a second exception to the sympathetic division of ANS?

Innervation of sweat glands, external genitalia, some skeletal muscle blood vessels. Here the post ganglionic neuron releases ACh not norepinephrine

179

What about the pre ganglionic cell is the same in both sympathetic and parasympathetic divisions?

It is ALWAYS myelinated sneaking out of spinal cord and ALWAYS releases ACh

180

How is the post ganglionic neuron different in sympathetic and parasympathetic?

Sympathetic- releases norepinephrine
Parasympathetic- ACh

181

Difference between pre and post ganglionic in both sympathetic and parasympathetic

Pre- myelinated
Post- not myelinated !!

182

Cholinergic receptors (membrane proteins)

Receptors that respond to ACh

183

2 different cholinergic receptors that bind ACh and other molecules with similar activity

Muscarinic (excite or inhibit)
and
Nicotinic (excite only)

184

Cholinergic fibers

Nerve fibers (cells) which produce (excite) ACh

185

Muscarinic receptors

-either excite or inhibit
-stimulated by muscarine (respond to mushroom poison)

186

Nicotinic receptors

-Stimulated by/respond to nicotine
-excite

187

Can you OD on nicotine?

Yes

188

Does it have to be ACh that turns on the cholinergic fibers: muscarinic receptors and Nicotinic receptors?

No, some chemicals can turn these on even though they're not ACh

189

Two catecholamines

-Norepinephrine and epinephrine

190

What can adrenergic receptors do and where are they found?

️-Bind catecholamines (epinephrine and norepinephrine) and other molecules with similar activity
- found on autonomic effector organs regulated by catecholamines

191

Alpha receptors

Norepinephrine/epinephrine
EXCITATORY

192

Beta receptors

Norepinephrine/epinephrine
INHIBITORY

193

Why are there exceptions for both beta and alpha receptors of adrenergic receptors?

Because of the existence of different alpha and beta subtypes

194

What's an example of a beta receptor exception?

Beta heart receptors- increased heart activity! (Excite instead of the normal function to inhibit)

195

Adrenergic fibers produce ...

NOREPINEPHRINE

196

Epinephrine is produced by...

ADRENAL MEDULLA