Chapter 14: The Brain And Cranial Nerves

Front 1

Cerebrum

Back 1

largest part of the brain with ridges,called gyri, and depressions called sulci

Functions:conscious thought, memory storage and processing, control skeletal muscles

Front 2

Cerebellum

Back 2

second largest part of brain, also has gyri and sulci

Functions:muscle coordination

Front 3

Diencephalon

Back 3

(3 parts)

Thalamus

Hypothalamus

Epithalamus

Front 4

Thalamus

Back 4

relay and processing center of sensoryinformation

Front 5

Hypothalamus

Back 5

emotions, hormones, autonomic function

Front 6

epithalamus

Back 6

sleep cycles

Front 7

Brain Stem

Back 7

Midbrain

Pons

Cuada equina

Front 8

Midbrain

Back 8

processes visual and auditory information, andmaintain consciousness

Front 9

pons

Back 9

relays information to cerebellum

Front 10

Cuada equina

Back 10

relays information to thalamus,autonomic control of heart rate, breathing rate, and blood pressure

Front 11

VENTRICLES ANDCEREBROSPINAL FLUID

Back 11

the brain has 4 internal chambers called ventricles

Front 12

2 lateral ventricles

Back 12

which run like rams horns within the cerebralhemispheres; they are separated by the septumpellucidum

Front 13

septum pellucidum

Back 13

a thin membrane

Front 14

interventricular foramen

Back 14

connectthird ventricle tolateral ventricles

Front 15

corpus aqueduct

Back 15

- connects to a fourth ventricle

in the midbrain of the brain stem

Front 16

CRANIAL MENINGES

Back 16

includes duramater, arachnoid mater, pia mater

Front 17

dura mater

Back 17

consists of 2 layers:

periosteal layer

meningeal layer

Front 18

periosteal layer

Back 18

lines the inside of the cranium, between thebrain and skull

Front 19

meningeal layer

Back 19

overlies the arachnoid mater surrounding thebrain only

Front 20

3 Dural Folds

Back 20

1. falx cerbri

2. tentoriumcerebelli – “tent”

3. falx cerebelli

Front 21

falx cerbri

Back 21

a fold of dura mater separating the left andright cerebral hemispheres

-superior sagittal and inferior sagittal sinuses

Front 22

superior sagittal and inferior sagittal sinuses

Back 22

run along midsagittal line of cranium, collectsvenous blood and CSF then empties into the jugular veins

Front 23

tentorium cerebelli – “tent”

Back 23

separates cerebrum from cerebellum

--- transversesinus

Front 24

Transverse sinus

Back 24

runs transversely from theoccipital region toward each ear, aids in blood removal from the brain

Front 25

falx cerebelli

Back 25

separates left and right lobes of cerebellum

Front 26

CEREBRAL SPINAL FLUID(CSF)

Back 26

serves 3 basic functions:

1. buoyancy

2. protection

3. chemical stability

Front 27

buoyancy

Back 27

the brain can grow large without being damaged by its own weight

Front 28

protection

Back 28

protects the brain from colliding with the skull

Front 29

chemical stability

Back 29

rinses away metabolic wastes of highly activebrain cells

Front 30

choroid plexus

Back 30

a network of blood capillaries covered in ependymal cells, which both fill theventricles with cerebrospinal fluid

Front 31

cerebrospinal fluid

Back 31

filtered blood plasma so that it has more Na+ andCl- ions and less K+, Ca+ ions, glucose orproteins

*½ a liter (17oz.) is produced and reabsorbed bythe brain each day

Front 32

arachnoid villi

Back 32

reabsorbed CSF

- protrude from the arachnoid mater through the dura mater andinto the superior sagittal sinus

Front 33

hydrocephalus

Back 33

“water on the brain”

– problem with reabsorption of CSF through arachnoid villi

Front 34

Epiduralhemorrhage

Back 34

(arterial = higher blood pressure) – head injuryleading to bleeding between the dura mater and skull; may lead tounconsciousness and death

Front 35

subdural hemorrhage

Back 35

(venous = lower blood pressure and slower effects)– bleeding between the dura and arachnoid mater

Front 36

Blood –Brain barrier

Back 36

the endothelial cells of the capillaries aretightly joined by the perivascular feet of astrocytes to prevent anything frompassing from the blood to the brain unless it goes through the endothelialcells themselves

Front 37

circumventricular organs (CVO)

Back 37

places in the third and fourth ventricles where the bloodand brain have direct access to each, enables the brain to monitor bloodglucose, pH, osmolarity and other variables

Front 38

cerebrovascular accident or stroke

Back 38

blood supply to a portion of the brain is shut off, due toan embolus (floating blood clot)

Front 39

THE BRAIN CONSISTS OF3 MAJOR PORTIONS: HINDBRAIN, MIDBRAIN, AND FOREBRAIN

Back 39

1. HINDBRAIN2. MIDBRAIN3. FOREBRAIN

Front 40

hindbrain

Back 40

- includes medulla oblongata, pons, andcerebellum

Front 41

MEDULLA OBLONGATA

Back 41

- directly superior to the spinal cord, the most inferiorportion of the brain

Front 42

Includes 3 groups of Nuclei

Back 42

1. Autonomic NucleiControlling Visceral Activities- contains the vital centers (motor nuclei) necessary forsurvival

cardiac center- regulates rate andforce of heartbeat

vasomotor center- regulates bloodpressure

respiratory centers- regulates rate anddepth of breathing

2. Sensory and MotorNuclei of Cranial Nerves 8-12- cranial nerves that originate from the medulla:glossopharyngeal (IX), vagus (X), accessory (XI), and hypoglossal (XII)

- controls muscles of pharynx, neck and visceral organs

3. Relay Stationsalong Sensory and Motor Pathways

- nucleus gracilis (sensoryfrom lower body) and nucleus cuneatus(sensory from upper body) are 2 tracts that lead to the thalamus and _____________________________ (crossover) to the opposite side at the pyramids,anterior swellings

Front 43

PONS

Back 43

connects the cerebellum to the other parts ofthe brain

Front 44

apneustic and pneumotaxis centers

Back 44

modify breathing rates

Front 45

CEREBELLUM

Back 45

mainly involved in balance and equilibrium, as well ascoordination

- largest portion of the hindbrain, second largest part ofthe brain

Front 46

folia

Back 46

2 hemispheres of the CEREBELLUM

Front 47

vermis

Back 47

along the midlineof the CEREBELLUM

Front 48

Arbor Vitae

Back 48

the white matter resembles a “tree of life”

- has 4 deep nuclei,masses of gray matter embedded in the white matter, where all of the outputsignals come from

Front 49

cerebellar peduncles

Back 49

connect the cerebellum to the midbrain, diencephalon,cererbrum, pons, and medulla oblongata

Front 50

* Ataxia

Back 50

a disturbance in coordination, possibly due todrugs, alcohol or trauma

Front 51

. MIDBRAIN

Back 51

connects the hindbrain to the forebrain

gives rise to 2 cranial nerves controlling eye movements:the oculomotor (III) and the trochlear (IV)

- contains the cerebralaqueduct connecting the third and fourth ventricles

Front 52

Major Regions of the Midbrain

Back 52

tectum “roof”-contains the corpora quadrigemina quadruplets”

Corporaquadrigemina composed of 2 pairs of nuclei

1. Superior colliculus

2.inferior colliculus

tegmentum and red nuclei-

cerebral pedunclessubstantia nigra

Reticular ActivatingSystem (RAS)

Front 53

* Parkinson’sdisease

Back 53

deterioration of neurons in the substantia nigra leading touncontrolled muscle contractions

Front 54

Superior colliculus

Back 54

receives visual information andcontrols reflexes to visual cues

Front 55

.inferiorcolliculus

Back 55

receives auditory information and controlsreflexes to sounds

Front 56

tegmentum andred nuclei

Back 56

the main mass of the midbrain, collaborates withcerebellum in fine motor control and muscle tone

Front 57

cerebral peduncles

Back 57

anchor the cerebrum to the brainstem

Front 58

substantia nigra

Back 58

“black substance” due to melanin pigment, a motor centerthat relays signals to the thalamus and basal nuclei, center of dopamine synthesis

Front 59

Reticular Activating System (RAS)

Back 59

part of reticular formation; controls alertness andconsciousness

Front 60

- reticular formation

Back 60

is a an organized web of gray matter that runs verticallythrough all levels of the brain stem and to the cerebrum.

Front 61

Functionsofreticular formation

Back 61

- somatic motorcontrol

cardiovascularcontrol

pain modulation

sleep andconsciousness

habituation

Front 62

somatic motor control

Back 62

some motor neurons from the cerebrum give rise to the reticulospinal tract ofthe spinal cord, which modulate tone, balance and posture.

Thisincludes the gaze center for fixatingthe eyes on moving objects and the centralpattern generator controlling rhythmic patterns of breathing and swallowing

Front 63

cardiovascular control

Back 63

includes cardiac and vasomotor center of medulla

Front 64

pain modulation

Back 64

descendinganalgesic pathways block transmission of pain signals

Front 65

sleep and consciousness

Back 65

has projections to the thalamus andcerebral cortex allowing control over what sensory signals reach the cerebrum(our consciousness)

Front 66

habituation

Back 66

brain learns to ignore repetitive signals whileremaining sensitive to new ones. An example being, you cannot feel your watchafter several minutes, but you can still feel a fly crawling on your arm.

Front 67

FOREBRAIN

Back 67

– includes the diencephalon and cerebrum

Front 68

DIENCEPHALON

Back 68

consists of 3 major derivatives: thalamus, hypothalamus, epithalamus

Front 69

1. Epithalamus

Back 69

very small mass of tissue

contains Pinealgland

Front 70

Pineal gland

Back 70

produces melatonin,involved in sleep and possibly onset of puberty

Front 71

Thalamus

Back 71

“gateway to the cerebral cortex”

- passes nearly all sensory input going to the cerebrumthrough its thalami nuclei

- includes signals for: taste, smell, hearing, equilibrium,vision, touch, pain, pressure, heat and cold

- the thalamus acts as a filter for the passing information

- plays a key role in motor control relaying signals fromcerebellum to cerebrum

- involved in memory and emotional functions of the limbicsystem

- plays a part in waking up or becoming alert

- plays a role in expressing emotions such as rage and fear

Front 72

. Hypothalamus

Back 72

major control center of the autonomic nervous system andendocrine system- structures of the hypothalamus include:

optic chiasma

infundibulum

Pituitary gland

Mammillary bodies

hormone secretion

autonomic effects

thermoregulation

food and water intake

sleep and circadianrhythms

emotional behavior

memory

Front 73

optic chiasma

Back 73

the crossing place for the optic nerves of theeyes

Front 74

infundibulum

Back 74

the stalk of the pituitary gland

Front 75

Pituitary gland

Back 75

a major control center of the endocrine system

Front 76

Mammillary bodies

Back 76

feeding reflexes like suckling andswallowing- plays a major role in the homeostatic regulation ofnearly all the organs of the body

Front 77

hormone secretion

Back 77

regulates growth, metabolism, reproduction, stress responses,labor contractions, lactation, and water conservation

Front 78

autonomic effects

Back 78

controls the “fight or flight” responses

Front 79

thermoregulation

Back 79

acts as a thermostat, controlsvasodilation, vasoconstriction, sweating, shivering and piloerection

Front 80

food and water intake

Back 80

monitors blood glucose and produceshunger pains, also stimulates antidiuretic hormone which conserves water

Front 81

sleep and circadian rhythms-

Back 81

regulates sleeping and waking

Front 82

memory

Back 82

lie in the pathway of memories between thehippocampus and thalamus

Front 83

emotional behavior

Back 83

part of the system involved inexpressing emotions

Front 84

LIMBIC SYSTEM

Back 84

border between the diencephalon and cerebrum

Front 85

Functions ofLIMBIC SYSTEM

Back 85

1. emotions

2. links conscious cerebrum to unconscious autonomicfunction of brain stem

3. memory storage and retrieval

Front 86

amygdala

Back 86

links emotions to memories, like fear at thesight of a rattlesnake

Front 87

cingulate gyrus

Back 87

superior to corpus callosum

Front 88

Hippocampus

Back 88

important in storing memories, as we sleep, itdecides which events in our day to forget and which we remember

Front 89

CEREBRUM

Back 89

the “conscious mind”

- largest portion of the brain

- composed of 2 cerebralhemispheres separated by a longitudinalfissure

- has many gyri (folds) and sulci (depressions between gyri) which increase the brains surfacearea

Front 90

Cerebral Cortex

Back 90

– outer layer of gray matter, cortical neurons called pyramidal cells

- one hemisphereis made up of 5 Lobes:

1. frontal lobe

2. parietal lobe

3. occipital lobe

4. temporal lobe

5. insula

Front 91

frontal lobe-

Back 91

voluntary motor functions,motivation, foresight, planning, memory, mood, emotion, social judgement,and aggression

Front 92

2. parietal lobe

Back 92

sensory perception and integrationof somesthetic, taste, and some visual information

Front 93

occipital lobe

Back 93

visual center of the brain

Front 94

. temporal lobe

Back 94

hearing, smell, learning, memory,visual recognition, and emotional behavior

Front 95

. insula

Back 95

understanding spoken language,sense of taste, integrating sensory information from visceral receptors

Front 96

White Matter

Back 96

- association fibers

-commissural fibers

- projection fibers

Front 97

association fibers

Back 97

interconnect lobes within the same hemisphere

Front 98

commissural fibers

Back 98

connect the different hemispheres

includes a thick bundle of nerve fibers called the corpus callosum

Front 99

- projection fibers

Back 99

– collectively known as the internal capsule connect the cortex to the diencephalon, brainstemand cerebellum

Front 100

Deep Nuclei – Gray Matter

Back 100

- basal nuclei

- corpus striatum

Front 101

- basal nuclei

Back 101

masses of cerebral gray matter buried deep in the whitematter, lateral to the thalamus, includes 3 nuclei

** the basalnuclei are inhibited by dopamine from themidbrain, thus Parkinson’s leads to increased muscle tone, opposing muscleswill not relax during voluntary movements

Front 102

corpus striatum

Back 102

includes 3 nuclei: caudate nucleus, putamen globus pallidus

Front 103

Primary Motor cortex (precentral gyrus)

Back 103

voluntary control of skeletal muscles

Front 104

somatic motor association area (premotor cortex)

Back 104

– coordinates learned movements, itplans the movements before they start

Front 105

gustatory cortex

Back 105

taste

Front 106

frontal lobe

Back 106

Primary Motor cortex (precentral gyrus)

somatic motor associationarea (premotor cortex)

gustatory cortex

Front 107

Parietal Lobe

Back 107

primary sensorycortex (postcentral gyrus

somatic sensoryassociation area

Front 108

primary sensorycortex (postcentral gyrus

Back 108

receive somatic sensory information abouttouch, pressure, pain, and temperature

Front 109

somatic sensoryassociation area

Back 109

makes us aware of the positions ofour limbs, and location of touch or pain, and the shape, weight, and texture ofobjects in our hands

Front 110

Occipital Lobe

Back 110

-visual cortex

- visual associationarea

Front 111

visual cortex

Back 111

conscious perception of visual stimuli

Front 112

visual association area

Back 112

spatial perception, recognition of faces andother objects

Front 113

Temporal Lobe

Back 113

auditory and olfactory cortexauditory

associationarea

Front 114

- auditory andolfactory cortex

Back 114

conscious perception of hearing and smell

Front 115

auditory association area

Back 115

remember name of song by hearing itor identify people by their voice

Front 116

INTEGRATIVE CENTERS

Back 116

Prefrontal cortex

Wernicke’s area(usually in left hemisphere)

Broca’s area (usuallyin left hemisphere)

Front 117

Prefrontal cortex

Back 117

integrates information from sensory association areas and“thinks” about them, predicts consequences etc.; doesn’t develop fully untilthe early 20’s- controls feelings of anxiety,frustration associated with predicting the outcome of events; if removed by frontal lobotomy, anxiety removed andso are socially acceptable actions like not flatulating in public

Front 118

Wernicke’s area (usually in left hemisphere)

Back 118

responsible for the recognition of spoken and writtenlanguage, formulates phrases according to learned grammar and transmits to theBroca area

Front 119

Broca’s area (usually in left hemisphere)

Back 119

generates a motor program for the muscles of the larynx,.tongue, cheeks, and lips to produce speech

Front 120

aphasia-

Back 120

any language deficit resulting from lesions inthe hemisphere containing the Wernicke’s and Broca’s areas

Front 121

CEREBRAL LATERALIZATION

Back 121

the 2 hemispheres of your brain differ in function:

- categorical hemisphere

-representationalhemisphere

Front 122

categorical hemisphere

Back 122

- usually the lefthemisphere, specialized for spoken and written language, and the sequential andanalytical reasoning used in areas such as science and math

Front 123

representational hemisphere

Back 123

usually the right hemisphere, used in imagination, insight,music and artistic skill, as well as perception of patterns and comparisons oftastes, smells and sounds

- adult males exhibit more lateralization and thus suffermore functional loss when a hemisphere is damaged than do women

- this is thought to be due to a thicker caudal portion ofthe corpus callosum in women, thought to provide better communication betweenthe 2 hemispheres

Front 124

brain waves

Back 124

rhythmic voltage changes resulting from synchronizedpostsynaptic potentials in the superficial layers of the cerebral cortex

Front 125

electroencephalogram (EEG)-

Back 125

recordings of brain waves4 types of brain waves:

1. alpha (a)waves

2. beta (b)waves

3. theta (q)waves

4. delta (d)waves

Front 126

Cranial nerves

Back 126

Olfactory (I)

Optic (II)

OCULOMOTOR (III)

TROCHLEAR (IV)

Trigeminal (V)

ABDUCENS (VI)

Facial (VII)

Vestibulochochlear (VIII)

GLOSSOPHARYNGEAL (IX)

Vagus(X)

ACCESSORY (XI)

HYPOGLOSSAL (XII)

Front 127

Olfactory(I)

Back 127

sensory; sense of smell

-olfactory foramen

*CN1 is the only cranial nerve that does not pass through thethalamus on the way to the olfactory cortex

Front 128

Optic(II)-

Back 128

sensory; sense of sight

- optic foramen

Front 129

OCULOMOTOR (III)-

Back 129

motor; eye movements and upper eyelid movements

- superior orbitalfissure

Front 130

TROCHLEAR (IV)

Back 130

motor; eye movement medially

- superior orbitalfissure

Front 131

Trigeminal (V

Back 131

divided into 3 divisions ophthalmic(V1), maxillary (V2­) mandibular (V3)

ophthalmic- sensory; touch, temperature, pain of upperface

-superior orbital fissure

maxillary- sensory; tough, temperature, pain of middle face

- foramen rotundum

mandibular- mixed (sensory/motor); sensory- touch, temperature,pain of lower face motor- mastication

- foramen ovale

Front 132

ABDUCENS (VI)-

Back 132

motor; eye movement laterally

-superior orbital fissure

Front 133

Facial(VII)

Back 133

mixed (sensory/motor);

sensory- taste

motor- facial expression, secretion of tears, saliva, nasal and oral mucus

- stylomastoid foramen

*CN7 passes through the parotid gland, but does not innervateit.

Front 134

Vestibulochochlear (VIII)-

Back 134

sensory; hearing and equilibrium;

-internal acoustic meatus

Front 135

GLOSSOPHARYNGEAL (IX)

Back 135

mixed;

sensory- taste, touch, pressure, pain, temperature sensations from tongue, outer ear,regulation of blood pressure and respiration

motor- salivation, swallowing, gagging;

-jugular foramen

*CN9 innervates the parotid.

Front 136

Vagus(X)-

Back 136

mixed;

sensory- taste, sensations of hunger, fullness, andgastrointestinal pain;

motor- swallowing, speech,deceleration of heart, bronchoconstriction,gastrointestinal secretion and motility

-jugular foramen

Front 137

ACCESSORY (XI)

Back 137

motor; swallowing, head, neck, and shouldermovements;

-jugular foramen

Front 138

HYPOGLOSSAL (XII)-

Back 138

motor; tongue movements of speech, food manipulation, and swallowing;

-hypoglossal canal

Front 139

Somatic Reflexes

Back 139

Corneal reflex –contact with eye (trigeminal - sensory) stimulates blinking (facial – motor)

Tympanic reflex –very loud noise (cochlear – sensory) reduces movement of ossicles (facial –motor) preventing damage

Auditory reflex-loud noise (cochlear – sensory) movement of head (accessory – motor)

Front 140

Visceral ReflexesDirect light reflex

Back 140

bright light (optic – sensory) constriction of pupil (oculomotor – motor)

Front 141

Cerebral Palsy

Back 141

motor disorders caused by damage to the motor areas of thebrain during fetal life, birth, or infancy. It is irreversible. May be causedby German measles (rubella), during the first three months of pregnancy.Characterized by partial paralysis and a lack of muscular coordination. 70% ofcerebral palsy victims appear to be mentally retarded, but they are not

Front 142

Multiple Sclerosis

Back 142

An autoimmune disease of the CNS characterized by loss ofmyelin and the appearance of scar like patches throughout the brain and spinalcord or both. Impulse transmission is interrupted. The onset of age is between20-40 years of age, and affects females 2x as often as males. Death may occur7-30 years later.

Front 143

Epilepsy

Back 143

Second most common disorder of the brain. Characterized bytemporary disturbances in normal brain impulses. May be accompanied byconvulsive seizures and loss of consciousness.

Front 144

Brain tumors

Back 144

benign or malignant growth within the cranium

Front 145

Dyslexia

Back 145

- Involves an inability of an individual tocomprehend written language. Letters seem transposed, reversed, or upside down

Front 146

Reye’s syndrome

Back 146

- Seems to occur following a viral infection, particularlychickenpox or the flu. Aspirin at normal doses is believed to be a risk factorin the development of Reye’s syndrome. Characterized by vomiting, braindysfunction, and liver damage

Front 147

Transient Ischemic Attack (TIA)-

Back 147

An episode of temporary cerebral dysfunction caused byimpaired blood flow to the brain. The attack usually persists for 5-10 minutesand only rarely lasts as long as 24 hours. Estimated that about 1/3 of patientswho experience a TIA will have a cerebral vascular accident within 5 years.