Chapter 16 218/Martini PPT... · Chapter 16 The Nervous System The Brain and Cranial Nerves ......

Lecture Presentation by

Steven Bassett

Southeast Community College

Chapter 16

The Nervous

System

The Brain and Cranial

Nerves

© 2015 Pearson Education, Inc.

Introduction

• The brain is a complex three-dimensional

structure that performs a bewildering

array of functions

• Think of the brain as an organic computer

• However, the brain is far more versatile than a

computer

• The brain is far more complex than the spinal cord

• The brain consists of roughly 20 billion neurons


An Introduction to the Organization of the Brain

• Embryology of the Brain

• The CNS begins as a neural tube

• The lumen of the tube (neurocoel) is filled with

fluid

• The lumen of the tube will expand thus forming the

various ventricles of the brain

• In the fourth week of development, the cephalic

area of the neural tube enlarges to form:

• Prosencephalon

• Mesencephalon

• Rhombencephalon


Table 16.1 Development of the Human Brain



• Embryology of the Brain (continued)

• Prosencephalon eventually develops to form:

• Telencephalon forms:

• Cerebrum

• Diencephalon forms:

• Epithalamus, thalamus, and hypothalamus.






• Mesencephalon

• Does not subdivide

• Becomes the midbrain






• Rhombencephalon

• Eventually develops to form:

• Metencephalon: forms the pons and cerebellum

• Myelencephalon: forms the medulla oblongata




Figure 16.1 Major Divisions of the Brain


Gyri

Sulci

Fissures

Spinal

cord

Brain

stem

Left cerebral

hemisphere

• Coordinates complex

somatic motor

patterns

• Adjusts output of

other somatic motor

centers in brain and

spinal cord

• Relays sensory information to thalamus and

to other portions of the brain stem

• Autonomic centers for regulation of visceral

function (cardiovascular, respiratory, and

digestive system activities)

• Relays sensory

information to

cerebellum and

thalamus

• Subconscious

somatic and visceral

motor centers

• Processing of visual

and auditory data

• Generation of reflexive

somatic motor

responses

• Maintenance of

consciousness

• Centers controlling

emotions, autonomic

functions, and hormone

production

• Relay and processing

centers for sensory

information

• Conscious thought processes,

intellectual functions

• Memory storage and processing

• Conscious and subconscious regulation

of skeletal muscle contractions

THALAMUS

HYPOTHALAMUS

CEREBELLUM

MEDULLA OBLONGATA

PONS

MESENCEPHALON

DIENCEPHALON

CEREBRUM


• Major Regions and Landmarks

• Medulla oblongata

• Pons

• Mesencephalon (midbrain)

• Diencephalon

• Cerebellum

• Cerebrum (telencephalon)


Figure 16.13a Sectional Views of the Brain


Postcentral gyrusCentral sulcus

Cingulate gyrus

Parieto-occipital sulcus

Fornix

Thalamus

Pineal gland

Hypothalamus

Superior colliculus

Inferior colliculus

Aqueduct of midbrain

Fourth ventricle

Cerebellum

Medulla oblongata

Pons

Temporal lobe

Mesencephalon

Mamillary body

Optic chiasm

Frontal lobe

Corpus callosum

Precentral gyrus

Membranous portion

of epithalamus

Corpora

Quadrigemina

Anterior

commissure

Interventricular

foramen

Septum

pellucidum

a A sagittal section

through the brain




• Relays information to the thalamus and brain stem

• Regulates heart rate, blood pressure, and digestion

• Pons

• Relays information to the cerebellum and the

thalamus

• Regulates somatic and visceral motor centers




Gyri

Sulci

Fissures

Spinal

cord

Brain

stem

Left cerebral

hemisphere


somatic motor

patterns


other somatic motor


spinal cord






• Relays sensory

information to

cerebellum and

thalamus

• Subconscious


motor centers


and auditory data


somatic motor

responses

• Maintenance of

consciousness


emotions, autonomic


production


centers for sensory

information






THALAMUS

HYPOTHALAMUS

CEREBELLUM

MEDULLA OBLONGATA

PONS

MESENCEPHALON

DIENCEPHALON

CEREBRUM



• Mesencephalon (midbrain)

• Processes visual and auditory data

• Maintains consciousness and alertness

• Involved with reflexive somatic motor responses to

stimuli




Gyri

Sulci

Fissures

Spinal

cord

Brain

stem

Left cerebral

hemisphere


somatic motor

patterns


other somatic motor


spinal cord






• Relays sensory

information to

cerebellum and

thalamus

• Subconscious


motor centers


and auditory data


somatic motor

responses

• Maintenance of

consciousness


emotions, autonomic


production


centers for sensory

information






THALAMUS

HYPOTHALAMUS

CEREBELLUM

MEDULLA OBLONGATA

PONS

MESENCEPHALON

DIENCEPHALON

CEREBRUM



• Diencephalon

• Epithalamus

• Contains the pineal gland

• Thalamus

• Relays information to the cerebrum

• Processes sensory information

• Hypothalamus

• Involved in emotions, thirst, some habitual activity




Gyri

Sulci

Fissures

Spinal

cord

Brain

stem

Left cerebral

hemisphere


somatic motor

patterns


other somatic motor


spinal cord






• Relays sensory

information to

cerebellum and

thalamus

• Subconscious


motor centers


and auditory data


somatic motor

responses

• Maintenance of

consciousness


emotions, autonomic


production


centers for sensory

information






THALAMUS

HYPOTHALAMUS

CEREBELLUM

MEDULLA OBLONGATA

PONS

MESENCEPHALON

DIENCEPHALON

CEREBRUM



• Cerebellum

• Coordinates somatic motor function

• Adjusts output of somatic motor centers resulting in

smooth operation

• Cerebrum (telencephalon)

• Conscious thought processes

• Intellectual functions

• Memory storage

• Conscious regulation of skeletal muscle

contractions




Gyri

Sulci

Fissures

Spinal

cord

Brain

stem

Left cerebral

hemisphere


somatic motor

patterns


other somatic motor


spinal cord






• Relays sensory

information to

cerebellum and

thalamus

• Subconscious


motor centers


and auditory data


somatic motor

responses

• Maintenance of

consciousness


emotions, autonomic


production


centers for sensory

information






THALAMUS

HYPOTHALAMUS

CEREBELLUM

MEDULLA OBLONGATA

PONS

MESENCEPHALON

DIENCEPHALON

CEREBRUM


• Gray Matter and White Matter Organization

• The cerebrum consists of:

• Inner region of gray matter

• Surrounded by tracts of white matter

• Gray matter consists of cell bodies


Figure 16.2d Ventricles of the Brain


Septum

pellucidum

Inferior horn

of lateral

ventricles

Cerebellum

Lateral ventricles

in cerebral

hemispheres

Interventricular

foramen

Third ventricle

Aqueduct of

midbrain

Fourth ventricle

Ventricular System

of the Brain

Central canal

Diagrammatic coronal section showing the

interconnections between the ventriclesd


• The Ventricular System of the Brain

• Ventricles are fluid-filled cavities

• Filled with cerebrospinal fluid (CSF)

• Fluid transports nutrients to the CNS and

transports waste away from the CNS

• CSF also provides cushion for the CNS




• There are four ventricles

• Ventricles 1 and 2 (called lateral ventricles)

• Located in the cerebral hemispheres (separated by

a partition called the septum pellucidum)

• Ventricle 3 is in the diencephalon

• Ventricle 4 lies between the pons and the

cerebellum


Figure 16.2a Ventricles of the Brain


Pons

Medulla oblongata

Central canal

Spinal cord

Anterior horns

of lateral

ventricles

Cerebral

hemispheres

Lateral ventricles

Interventricular

foramen

Posterior horns of

lateral ventricles

Inferior horns of

lateral ventricles

Aqueduct of

midbrain

Fourth

ventricle

Cerebellum

Third ventricle

Orientation and extent of the ventricles as

seen in a lateral view of a transparent brain

a



• Lateral ventricles (ventricles 1 and 2)

• Main portion of the ventricle lies in the parietal

lobes

• Each has an anterior horn extending into the frontal

lobe

• Each has a posterior horn extending into the

occipital lobe

• Each has an inferior horn extending into the

temporal lobe

• Each communicates with the third ventricle

• Through the interventricular foramen




• Third ventricle

• Communicates with the fourth ventricle

• Through the aqueduct of the midbrain

• Fourth ventricle

• Communicates with the central canal of the spinal

cord


Figure 16.2a Ventricles of the Brain


Pons

Medulla oblongata

Central canal

Spinal cord

Anterior horns

of lateral

ventricles

Cerebral

hemispheres

Lateral ventricles

Interventricular

foramen

Posterior horns of

lateral ventricles

Inferior horns of

lateral ventricles

Aqueduct of

midbrain

Fourth

ventricle

Cerebellum

Third ventricle

Orientation and extent of the ventricles as

seen in a lateral view of a transparent brain

a

Figure 16.2c Ventricles of the Brain


Inferior horn

of lateral

ventricle

Pons

Cerebellum

Medulla oblongata

Central canal

Lateral ventricles

in cerebral

hemispheres

Interventricular

foramen

Third ventricle

Aqueduct of

midbrain

Fourth ventricle

Longitudinal

fissure

Ventricular System

of the Brain

Anterior view of the ventricles as if

seen through a transparent brain

c

Protection and Support of the Brain

• Protection involves:

• Bones of the skull

• Parietal, frontal, occipital, and temporal bones

• Cranial meninges

• Dura mater, arachnoid mater, and pia mater

• Cerebrospinal fluid

• Blood–brain barrier



• The Cranial Meninges

• The cranial meninges surround the brain and the

spinal cord

• There are three layers of the meninges

• Dura mater

• Most superficial layer (outermost layer)

• Arachnoid mater

• Middle layer

• Pia mater

• Deepest (innermost layer)


Figure 16.3a Relationships among the Brain, Cranium, and Meninges


Dura mater

(endosteal

layer)

Dural sinus

Dura mater

(meningeal

layer)

Subdural

space

Arachnoid

mater

Cranium

Cerebral

cortexPia

mater

Subarachnoid

space

Cerebral

cortex

Cerebellum

Medulla

oblongata

Spinal cordLateral view of the brain showing

its position in the cranium and the

organization of the meningeal coverings.

a

Figure 16.4 The Cranial Meninges, Part I


Looseconnectivetissue and

periosteumof cranium

Epicranial

aponeurosis

Scalp

Cranium

Dura mater

Subarachnoid

space

Arachnoid

mater

Cerebral

cortex

covered

by pia mater

POSTERIOR

ANTERIOR



• The Dura Mater

• Consists of two layers

• Endosteal layer

• Outermost layer of the dura mater

• This is the layer felt within the anterior fontanel of a

baby

• Fused to the periosteum lining of the cranial bones

• Meningeal layer

• Innermost layer of the dura mater

• Space between the two layers contains the dural

sinus




Dura mater

(endosteal

layer)

Dural sinus

Dura mater

(meningeal

layer)

Subdural

space

Arachnoid

mater

Cranium

Cerebral

cortexPia

mater

Subarachnoid

space

Cerebral

cortex

Cerebellum

Medulla

oblongata




a



• Folds of the dura mater

• The meningeal layer forms folds called:

• Falx cerebri

• Tentorium cerebelli

• Talx cerebelli

• Diaphragma sellae



• Folds of the Dura Mater

• Falx cerebri

• Meningeal layer that extends into the longitudinal

fissure

• Inferior/anterior portion attaches to the crista galli

• Inferior/posterior portion attaches to the internal

occipital crest and the tentorium cerebelli

• Tentorium cerebelli

• Separates the cerebellar hemispheres from the

cerebral hemispheres

• Extends across the cranium at right angles to the

falx cerebri



• Folds of the Dura Mater (continued)

• Falx cerebelli

• Extends from the tentorium cerebelli to separate

the cerebellar hemispheres

• Diaphragma sellae

• Lines the sella turcica of the sphenoid bone

• It anchors the dura mater to the sphenoid bone

• It encases the pituitary gland


Figure 16.5a The Cranial Meninges, Part II


Superior sagittal

sinus

Subdural

space

Arachnoid

granulation

Falx cerebri

Subarachnoid

space Cerebral cortex

Dura mater

Arachnoid mater

Arachnoid

trabeculae

Pia mater

Cranial

Meninges

Cerebral vein

Organization and relationship of

the cranial meninges to the brain.

a

Figure 16.3b Relationships among the Brain, Cranium, and Meninges


Superior sagittal sinus

Inferior sagittal sinus

Cranium

Dura Mater

Falx cerebri

Tentorium

cerebelli

Diaphragma

sellae

Falx cerebelli

Transverse sinus

Diaphragma

sellae

Pituitary gland

Sella turcica

of sphenoid

A corresponding view of the cranial cavity with

the brain removed showing the orientation and

extent of the falx cerebri and tentorium cerebelli.

b



• The Arachnoid Mater

• Consists of projections called arachnoid

granulations

• CSF flows through these to enter into venous

circulation

• Consists of weblike material underlining the

arachnoid layer

• These collagenous fibers help anchor cerebral

blood vessels




Dura mater

(endosteal

layer)

Dural sinus

Dura mater

(meningeal

layer)

Subdural

space

Arachnoid

mater

Cranium

Cerebral

cortexPia

mater

Subarachnoid

space

Cerebral

cortex

Cerebellum

Medulla

oblongata




a



• The Pia Mater

• Attached to the surface of the brain

• Follows the sulci and gyri of the brain

• Helps to anchor the larger blood vessels of the

cerebrum


Figure 16.5a The Cranial Meninges, Part II


Superior sagittal

sinus

Subdural

space

Arachnoid

granulation

Falx cerebri

Subarachnoid

space Cerebral cortex

Dura mater

Arachnoid mater

Arachnoid

trabeculae

Pia mater

Cranial

Meninges

Cerebral vein

Organization and relationship of

the cranial meninges to the brain.

a

Figure 16.5b The Cranial Meninges, Part II


Dura mater

Arachnoid mater

Arachnoid

trabeculae

Pia mater

Cranial

Meninges

Cerebral vein

Perivascular space

Subdural

space

Subarachnoid

space

Cerebral

cortex

A detailed view of the arachnoid mater,

the subarachnoid space, and the pia

mater. Note the relationship between

the cerebral vein and the subarachnoid

space.

b


• Blood–Brain Barrier

• The lining of the blood vessels consists of

endothelial cells that are highly interconnected by

tight junctions

• Due to this tight connection, only lipid-soluble

material can pass from the blood to the cells of the

brain and spinal cord

• Water-soluble material can only pass via the action

of transport mechanisms

• These transport mechanisms are very specific



• Blood–Brain Barrier

• The blood-brain barrier is intact throughout the

CNS except in three areas

• Portions of the hypothalamus

• Pineal gland

• The roof portions of the third and fourth ventricles



• Cerebrospinal Fluid (CSF)

• Prevents contact of neural tissue with the

surrounding bones

• Provides support

• Transports nutrients to the CNS tissue

• Transports waste away from the CNS



• Formation of CSF

• Produced by the ependymal cells of the choroid

plexus

• They actively transport nutrients, vitamins, and

ions into the CSF

• They actively remove waste from the CSF


Figure 16.6 The Choroid Plexus and Blood–Brain Barrier


The location of the choroid plexus in

each of the four ventricles of the brain.

The structure and function of the

choroid plexus. The ependymal

cells are a selective barrier, actively

transporting nutrients, vitamins,

and ions into the CSF. When

necessary, these cells also actively

remove ions or compounds from

the CSF to stabilize its composition. CEREBROSPINAL FLUID IN THIRD VENTRICLE

CHOROID PLEXUS

Tight junction

Capillary

Ependymal

cells

INTERSTITIAL FLUID IN THALAMUS

Nutrients

(especially glucose)

Oxygen

Capillary

Endothelial cell

Tight

junction

CO2

Waste products

Astrocyte Neuron

Blood–brain

barrier

Choroid

plexus

cellsWaste products

Ions

Amino acids

(when necessary)

Ions

(Na+, K+, Cl–, HCO3–, Ca2+, Mg2+)

Vitamins

Organic nutrients

Oxygenb

a


• Circulation of CSF

• CSF from the choroid plexus of the lateral ventricles

• Flows through the interventricular foramen

• Flows into the third ventricle

• Flows into the aqueduct of the midbrain

• Flows into the fourth ventricle

• Through the lateral aperture and median aperture

• Most flows into the subarachnoid space and a small

amount enters the central canal of the spinal cord

• Flows around the brain and spinal cord eventually

enters circulation via the arachnoid granulations


Figure 16.7 Circulation of Cerebrospinal Fluid


Extension of

choroid plexus

into lateral ventricle

Arachnoid

granulations

Superior

sagittal sinus CraniumDura mater

(endosteal

layer)

Arachnoid

granulation

Fluid

movement

Arachnoid

trabecula

Dura mater

(meningeal

layer)

Subdural

space

Arachnoid

mater

Subarachnoid

space

Pia

mater

Cerebral

cortex

Superior

sagittal

sinus

Central

canal

Spinal

cord

Filum

terminale

Choroid plexus

of third ventricle


Lateral aperture

Choroid plexus of

fourth ventricle

Median aperture

Arachnoid mater

Subarachnoid space

Dura mater

The Medulla Oblongata

• The medulla oblongata is continuous with the

spinal cord to the brain stem

• All communication between the brain and spinal

cord passes through the medulla oblongata

• Nuclei in the medulla oblongata are:

• Relay stations for sensory or motor pathways

• Associated with cranial nerves connected to the

medulla oblongata

• Associated with the autonomic control of visceral

organs



• Relay Stations

• Nucleus gracilis and nucleus cuneatus

• Pass somatic sensory information to the thalamus

• Olivary nuclei

• Pass information from the cerebrum, spinal cord,

diencephalon, and brain stem to the cerebellum


Figure 16.8a The Medulla Oblongata


Olivary nucleus

Nucleus cuneatus

Nucleus gracilis

Reticular formation

Cardiovascular centers

Pons

Solitary nucleus

Olive

Pyramids

Spinal cord Lateral white column

Anterior view

Medulla

oblongata

a


• Nuclei of Cranial Nerves

• Contains sensory and motor nuclei of cranial

nerves:

• VIII, IX, X, XI, and XII

• Autonomic Nuclei

• Major reflex centers include:

• Cardiovascular centers (cardiac and vasomotor)

• Respiratory centers (rhythmic breathing)


Figure 16.8b The Medulla Oblongata


Posterior median sulcus

Posterior white columns

Lateral white column

Posterolateral view

Olivary nuclei

Cardiovascular centers

Respiratory rhythmicity centers

Nucleus gracilis

Nucleus cuneatus

Other nuclei/centers

Reticular formation

Attachment to

membranous roof

of fourth ventricle

Spinal

cord

b

The Pons

• The pons is a prominent bulge superior to

the medulla oblongata and consists of:

• Sensory and motor nuclei for cranial nerves:

• V, VI, VII, and VIII

• Nuclei involved with involuntary control of

breathing:

• Consist of apneustic center and pneumotaxic

center

• Nuclei that relay cerebellar commands:

• Consist of cerebellar peduncles

• Ascending, descending, and transverse tracts


Figure 16.12a The Hypothalamus


Corpus

callosum

Septum

pellucidum

Fornix

Anterior

cerebral artery

Frontal lobe

Anterior

commissure

Optic chiasm

Optic

nerveInfundibulum

(cut)

Tuberal

area

Mamillary

body

Parietal

lobe

Choroid plexus in

epithalamus

Thalamus (surrounds

third ventricle)

Pineal gland

Hypothalamus

Aqueduct of

midbrain

Cerebellum

Fourth ventricle

Midsagittal section through the brain. This view shows the major features

of the diencephalon and adjacent portions of the brain stem.

a

Figure 16.9 The Pons


Cerebellum

Olivary nucleus

Medulla oblongata

Pons

Descending tracts

Ascending tracts

Transverse fibers

Pneumotaxic center

Apneustic center

Reticular formation

Fourth

ventricle

The Mesencephalon

• Mesencephalon (also called the midbrain)

• Consists of two pairs of nuclei collectively called

corpora quadrigemina

• Responsible for processing auditory and visual

stimuli

• Auditory processing occurs in the inferior

colliculus

• Visual processing occurs in the superior colliculus

• Consists of nuclei of the reticular formation

• Involved in maintaining alertness





Cingulate gyrus


Fornix

Thalamus

Pineal gland

Hypothalamus

Superior colliculus

Inferior colliculus


Fourth ventricle

Cerebellum

Medulla oblongata

Pons

Temporal lobe

Mesencephalon

Mamillary body

Optic chiasm

Frontal lobe

Corpus callosum

Precentral gyrus

Membranous portion

of epithalamus

Corpora

Quadrigemina

Anterior

commissure

Interventricular

foramen

Septum

pellucidum


through the brain

The Mesencephalon

• Mesencephalon (continued)

• Consists of:

• Red nucleus

• Integrates information between the cerebrum and

cerebellum

• Substantia nigra

• Regulates motor output of the basal nuclei

• Cerebral peduncles

• Have ascending fibers that synapse in the thalamus

and descending fibers of the corticospinal pathway


Figure 16.10b The Mesencephalon


Pineal gland

ThalamusSuperior colliculi

Inferior colliculi

Substantia nigra

Red nuclei

Reticular formation

Cerebral pedunclesDiagrammatic view of the diencephalon and

brain stem. This view is drawn as if transparent,

to show the positions of important nuclei.

b

The Diencephalon

• The diencephalon consists of:

• Epithalamus

• Thalamus

• Hypothalamus





Cingulate gyrus


Fornix

Thalamus

Pineal gland

Hypothalamus

Superior colliculus

Inferior colliculus


Fourth ventricle

Cerebellum

Medulla oblongata

Pons

Temporal lobe

Mesencephalon

Mamillary body

Optic chiasm

Frontal lobe

Corpus callosum

Precentral gyrus

Membranous portion

of epithalamus

Corpora

Quadrigemina

Anterior

commissure

Interventricular

foramen

Septum

pellucidum


through the brain

The Diencephalon

• The Epithalamus

• Forms the roof of the third ventricle

• Posterior portion contains the pineal gland

• Produces the hormone melatonin

• Regulates our day-night cycles


The Diencephalon

• The Thalamus

• Forms the walls of the third ventricle

• There is a right and a left thalamus

• Thalamic nuclei are egg-shaped

• Each thalamic nucleus is divided into:

• Anterior nuclei: part of the limbic system

• Medial nuclei: relay information to the frontal lobe

• Ventral nuclei: relay information to the parietal lobes

• Posterior nuclei: relay information to the occipital lobe

• Lateral nuclei: adjust activity in the cingulate gyrus


Figure 16.11a The Thalamus


Lateral view of the brain showing

the positions of the major thalamic

structures. Functional areas of

cerebral cortex are also indicated,

with colors corresponding to those

of the associated thalamic nuclei.

Frontal

lobeParietal lobe

Occipital

lobe

a

Figure 16.11b The Thalamus


Enlarged view of the thalamic nuclei of the left side. The color

of each nucleus or group of nuclei matches the color of the

associated cortical region. The boxes either provide examples

of the types of sensory input relayed to the basal nuclei and

cerebral cortex or indicate the existence of important feedback

loops involved with emotional states, learning, and memory.

Limbic

systemFrontal

lobes

Parietal lobe and

cingulate gyrus

Association areas

of cerebral cortex

Anterior

group

Medial group

Lateral group

Posterior

group

V e n t r a l

g r o u p

Basal

nuclei

Cerebellum

General

sensory

input

Visual

input

Auditory

input

Pulvinar

Medial

geniculate

nucleus

Lateral

geniculate

nucleus

b

The Diencephalon

• The Hypothalamus

• Forms the floor of the third ventricle

• Consists of numerous nuclei

• Consists of an infundibulum, which connects to

the pituitary gland

• Consists of the mamillary body on the posterior

wall of the hypothalamus





Cingulate gyrus


Fornix

Thalamus

Pineal gland

Hypothalamus

Superior colliculus

Inferior colliculus


Fourth ventricle

Cerebellum

Medulla oblongata

Pons

Temporal lobe

Mesencephalon

Mamillary body

Optic chiasm

Frontal lobe

Corpus callosum

Precentral gyrus

Membranous portion

of epithalamus

Corpora

Quadrigemina

Anterior

commissure

Interventricular

foramen

Septum

pellucidum


through the brain

The Diencephalon

• The Hypothalamus (continued)

• Consists of nuclei to control:

• Subconscious control of skeletal muscles

• Heart rate, blood pressure, respiration, and

digestive functions

• Secretion of antidiuretic hormone and oxytocin

• Emotional and behavioral drives and thirst drives

• Coordination between voluntary and autonomic

functions

• Body temperature

• Circadian rhythm


Figure 16.12b The Hypothalamus


Enlarged view of the

hypothalamus showing

the locations of major

nuclei and centers. Paraventricular nucleus

Preoptic area

Sympathetic

Parasympathetic

Tuberal nuclei

Mamillary bodies

Suprachiasmatic nucleus

Supraoptic nucleusPons

Thalamus

HypothalamusTuberal area

Optic chiasm

Infundibulum

Posterior lobe of

pituitary gland

Pars distalis

Pars intermediaAnterior lobe of

pituitary gland

b

The Cerebellum

• The Cerebellum consists of:

• Two hemispheres

• Folia cerebelli

• Folds similar to gyri of the cerebrum

• Anterior and posterior lobes

• Vermis (separates the hemispheres)

• Flocculonodular lobes

• Arbor vitae

• Cerebellar peduncles





Cingulate gyrus


Fornix

Thalamus

Pineal gland

Hypothalamus

Superior colliculus

Inferior colliculus


Fourth ventricle

Cerebellum

Medulla oblongata

Pons

Temporal lobe

Mesencephalon

Mamillary body

Optic chiasm

Frontal lobe

Corpus callosum

Precentral gyrus

Membranous portion

of epithalamus

Corpora

Quadrigemina

Anterior

commissure

Interventricular

foramen

Septum

pellucidum


through the brain

Figure 16.15a The Cerebellum


Posterior lobe

Vermis

Anterior lobe

Primary fissure

Cerebellum

Folia

Superior surface of the cerebellum. This view shows major anatomical landmarks and regions.

Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum

a

Figure 16.15b The Cerebellum (2 of 3)


Dendrites projecting into the

gray matter of the cerebellum

Cell body of Purkinje cell

Axons of Purkinje cells

projecting into the white

matter of the cerebellum Purkinje cells

Sagittal view of the cerebellum showing the arrangement of gray matter

and white matter. Purkinje cells are seen in the photomicrograph; these

large neurons are found in the cerebellar cortex.

LM 120

b

The Cerebellum

• The Cerebellum

• Cerebellar cortex

• Subconscious coordination of movements

• Arbor vitae

• Connects cerebellar cortex with cerebellar

peduncles

• Cerebellar peduncles

• Superior: connect cerebellum with mesencephalon,

diencephalon, and cerebrum

• Middle: communicate between cerebellum and pons

• Inferior: connect cerebellum with the medulla

oblongata


The Cerebrum

• The cerebrum consists of:

• Two hemispheres

• Several lobes

• Frontal, parietal, occipital, and temporal

• Gyri and sulci

• Longitudinal fissure

• Corpus callosum

• Basal nuclei

• Limbic system


Figure 16.16a The Cerebral Hemispheres, Part I


Right cerebral

hemisphere

Cerebral veins and

arteries covered by

arachnoid mater

Central sulcus

Parieto-occipital

sulcus

Longitudinal

fissure

Left cerebral

hemisphere

Cerebellum

POSTERIOR

ANTERIOR

Superior view.a

Figure 16.21c The Basal Nuclei


Frontal section

Caudate nucleus

Putamen

Globus pallidus

Claustrum

Amygdaloid body

Corpus

callosum

Lateral

ventricle

Septum

pellucidum

Insula

Lateral sulcus

Internal

capsule

Anterior

commissure

Tip of inferior

horn of lateral

ventriclec

The Cerebrum

• The Cerebral Hemispheres

• The hemispheres consist of:

• Gyri and sulci

• Central sulcus

• Longitudinal fissure

• Cerebral lobes

• Lateral sulcus


The Cerebrum

• The Cerebral Hemispheres

• The cerebral lobes

• Frontal lobe

• Conscious control of skeletal muscles

• Occipital lobe

• Perception of visual stimuli

• Parietal lobe

• Conscious perception of touch, pressure, vibration,

pain, temperature, and taste

• Temporal lobe

• Conscious perception of auditory and olfactory

stimuli


Figure 16.17b The Cerebral Hemispheres, Part II


Postcentral

gyrus

Parietal Lobe

Cerebellum

Occipital lobe

Precentral gyrus

Central sulcus

Frontal lobe

of left cerebral

hemisphere

Lateral sulcus

Branches of middle

cerebral artery emerging

from lateral sulcus

Temporal lobe

Pons

Medulla

oblongata

Lateral view of intact brain after removal of the

dura mater and arachnoid mater showing

superficial surface anatomy of the left hemisphere.

b

The Cerebrum

• The Insula

• Lies deep to the lateral sulcus

• Consists of olfactory cortex and gustatory cortex


Figure 16.17a The Cerebral Hemispheres, Part II


Parietal Lobe

Primary sensory cortex

(postcentral gyrus)

Somatic sensory

association area

Occipital Lobe

Visual association area

Visual cortex

Temporal Lobe (retracted

to show olfactory cortex)

Auditory association area

Auditory cortex

Olfactory cortexMajor anatomical landmarks on the surface of

the left cerebral hemisphere. To expose the

insula, the lateral sulcus has been pulled open.

Lateral sulcus

Insula

Gustatory cortex

Prefrontal cortex

Retractor

Primary motor cortex

(precentral gyrus)

Somatic motor

association area

(premotor cortex)

Frontal Lobe (retracted

to show insula)

Central sulcus

a

The Cerebrum

• Motor and Sensory Areas of the Cerebral Cortex

• Precentral gyrus

• Anterior to the central sulcus

• Neurons direct voluntary movements by controlling

somatic motor neurons in the brain stem and spinal

cord

• Postcentral gyrus

• Posterior to the central sulcus

• Neurons receive somatic sensory information for

touch, pressure, pain, taste, and temperature from

the dorsal columns and spinothalamic tracts


Figure 16.17b The Cerebral Hemispheres, Part II


Postcentral

gyrus

Parietal Lobe

Cerebellum

Occipital lobe

Precentral gyrus

Central sulcus

Frontal lobe

of left cerebral

hemisphere

Lateral sulcus

Branches of middle

cerebral artery emerging

from lateral sulcus

Temporal lobe

Pons

Medulla

oblongata

Lateral view of intact brain after removal of the

dura mater and arachnoid mater showing

superficial surface anatomy of the left hemisphere.

b

The Cerebrum

• Higher-Order Functions

• Characteristics of higher-order functions

• They are performed by the cerebral cortex

• They involve communication between cerebral

cortex areas and other areas of the brain

• They involve conscious and unconscious

information processing

• The functions are subject to modifications and

adjustments


The Cerebrum

• Integrative Regions of the Cerebral Cortex

• The centers of the various regions of the cerebral

cortex do the following:

• Integrate complex sensory stimuli

• Integrate complex motor responses

• The various centers are:

• General interpretive area

• The speech center

• The prefrontal cortex

• Brodmann’s areas


Figure 16.18a Integrative Regions of the Cerebral Cortex


Frontal eye field

General interpretive

area (gnostic area)

Speech center

(Broca’s area)

Prefrontal

association

cortex

Higher-order integrative regions of

the cerebral cortex

a

Figure 16.18b Integrative Regions of the Cerebral Cortex


44

4039

6

4

1

42

18

17

41

Selected Brodmann’s areas of the

cerebral cortex

b

The Cerebrum


• The general interpretive area

• Found only in one hemisphere, usually the left

• Analytical center

• The speech center

• Also called Broca’s area

• A motor center that regulates patterns of breathing

and vocalization for speech


The Cerebrum


• The prefrontal cortex

• Performs complicated learning and reasoning

functions

• Brodmann’s areas and cortical function

• Assigned numbers to various brain regions by

analyzing each area's cellular structure

• Perhaps the various cellular structures can

correlate with specific functions


The Cerebrum

• Hemispheric Specialization

• Left hemisphere

• Speech center, writing, language, mathematics

• Right hemisphere

• Analysis by touch, spatial visualization


Figure 16.19 Hemispheric Specialization


LEFT HAND RIGHT HAND

Prefrontal

cortex

Prefrontal

cortex

Anterior commissure

Analysis by touch

Auditory cortex

(left ear)

Spatial visualization

and analysis

Visual cortex

(left visual field)

Visual cortex

(right visual field)

General interpretive center

(language and mathematical

calculation)

Auditory cortex

(right ear)

Writing

Speech center

Left Cerebral Hemisphere Right Cerebral Hemisphere

CORPUS

CALL

OSUM

The Cerebrum

• The Central White Matter

• Consists of bundles called:

• Association fibers

• Tracts that interconnect areas of neural cortex within

a hemisphere (arcuate fibers and longitudinal

fasciculi)

• Commissural fibers

• Tracts that connect the two hemispheres (anterior

commissure and corpus callosum)

• Projection fibers

• Tracts that link the cerebrum with other regions of

the brain and spinal cord


Figure 16.20a The Central White Matter


Arcuate fibers

Longitudinal fasciculiLateral aspect of the brain

showing arcuate fibers and

longitudinal fasciculi

a

Figure 16.20b The Central White Matter


Longitudinal fissure

Internal capsule

Corpus callosum

Anterior commissure

Projection fibers

Anterior view of the brain

showing orientation of

the commissural and

projection fibers

b

The Cerebrum

• The Basal Nuclei

• These are masses of gray matter embedded in the

white matter inferior to the lateral ventricles

• General function:

• Involved with subconscious control and integration

of skeletal muscle tone

• Involved with the coordination of learned

movement patterns

• Involved in the processing, integration, and relay of

information from the cerebral cortex


The Cerebrum


• Consist of:

• Caudate nucleus

• Amygdaloid body

• Claustrum

• Putamen

• Globus pallidus


Figure 16.21c The Basal Nuclei


Frontal section

Caudate nucleus

Putamen

Globus pallidus

Claustrum

Amygdaloid body

Corpus

callosum

Lateral

ventricle

Septum

pellucidum

Insula

Lateral sulcus

Internal

capsule

Anterior

commissure

Tip of inferior

horn of lateral

ventriclec

The Cerebrum


• Caudate nucleus, putamen, and globus

pallidus

• Control the cycles of arm and leg movements when

walking

• Claustrum

• Plays a role in subconscious processing of visual

information

• Amygdaloid body

• Component of the limbic system


The Cerebrum

• The Limbic System

• Located between the cerebrum and the

diencephalon just superior to the corpus callosum

• Functions:

• Establishes emotional states

• Links the conscious functions with the unconscious

autonomic functions

• Facilitates memory storage and retrieval


Figure 16.22a The Limbic System


Interthalamic

adhesion

Central

sulcus

Cingulate gyrus

(limbic lobe)

Pineal glandFornix

Corpus

callosum

Thalamus

Hypothalamus

Temporal lobe

Parahippocampal

gyrus (limbic lobe)

Hippocampus

(within dentate gyrus)

Mamillary

body

Sagittal section through the cerebrum showing the cortical

areas associated with the limbic system. The parahippocampal

and dentate gyri are shown as if transparent so that deeper

limbic components can be seen.

a

The Cerebrum

• The limbic system consists of:

• Cingulate gyrus

• Dentate gyrus

• Parahippocampal gyrus

• Hippocampus


Figure 16.22b The Limbic System


Additional details concerning the

three-dimensional structure of the

limbic system.

Anterior nucleus

of thalamus

Hypothalamic

nuclei

Olfactory

tract

Amygdaloid

body

Mamillary

bodyHippocampus


Parahippocampal

gyrus

Corpus

callosum

Cingulate

gyrus Fornix

b

The Cerebrum

• The Limbic System

• The fornix

• Tract of white matter connecting the hippocampus

with the hypothalamus

• Many fornix fibers extend to the mamillary bodies

• Mamillary bodies control reflex movements

associated with eating


Figure 16.22b The Limbic System


Additional details concerning the

three-dimensional structure of the

limbic system.

Anterior nucleus

of thalamus

Hypothalamic

nuclei

Olfactory

tract

Amygdaloid

body

Mamillary

bodyHippocampus


Parahippocampal

gyrus

Corpus

callosum

Cingulate

gyrus Fornix

b

The Cranial Nerves

• There are 12 pairs of cranial nerves

• These nerves innervate the periphery emerging

from the brain (not the spinal cord)

• These nerves are on the ventrolateral surface of

the brain

• They are numbered beginning at the anterior

aspect of the brain

• They are numbered CN I to CN XII


Figure 16.23b Origins of the Cranial Nerves


Trochlear nerve (N IV)

Abducens nerve (N VI)

Vagus nerve (N X)

Accessory nerve (N XI)

Olfactory tract

Optic nerve (N II)

Optic chiasm

Infundibulum

Oculomotor nerve (N III)

Trigeminal nerve (N V)

Facial nerve (N VII)

Hypoglossal nerve (N XII)

Olfactory bulb, termination

of olfactory nerve (N I)

Vestibulocochlear

nerve (N VIII)

Glossopharyngeal

nerve (N IX)

Diagrammatic inferior view of the human

brain. Compare view with part (a).

b

Figure 16.23a Origins of the Cranial Nerves


Trochlear nerve (N IV)

Abducens nerve (N VI)

Vagus nerve (N X)

Accessory nerve (N XI)

Olfactory tract

Optic nerve (N II)

Optic chiasm

Infundibulum

Oculomotor nerve (N III)


Facial nerve (N VII)

Hypoglossal nerve (N XII)Medulla oblongata

Cerebellum

Spinal cord

Pons

Vertebral

artery

Basilar

artery

Mamillary

body

Olfactory bulb, termination

of olfactory nerve (N I)

Vestibulocochlear

nerve (N VIII)

Glossopharyngeal

nerve (N IX)

The inferior surface of the brain as it

appears on gross dissection. The roots of

the cranial nerves are clearly visible.

a

The Cranial Nerves

• CN I: The Olfactory Nerve

• Function

• Sensory (smell)

• Origin

• Olfactory epithelium

• Foramen

• Olfactory foramina

• Destination

• Olfactory bulbs


Figure 16.24 The Olfactory Nerve


Left olfactory bulb

(termination of

olfactory nerve)

Olfactory tract

(to olfactory cortex

of cerebrum)

Cribriform plate

of ethmoid

Olfactory epithelium

OLFACTORY

NERVE (N I)

Olfactory

nerve fibers

The Cranial Nerves

• CN II: The Optic Nerve

• Function

• Sensory (vision)

• Origin

• Retina

• Foramen

• Optic canal

• Destinatio

• Diencephalon, then to occipital lobe


Figure 16.25 The Optic Nerve


Olfactory bulb

Olfactory tract

Pituitary gland

Lateral geniculate

nucleus

(in thalamus)

Optic projection

fibers

Visual cortex

(in occipital lobes)

OPTIC NERVE

(N II)

Optic chiasm

Optic tract

Mesencephalon

(cut)

Eye

The Cranial Nerves

• CN III: The Oculomotor Nerve

• Function: controls extra-ocular eye muscles

• Motor function

• Superior, inferior, medial rectus, inferior oblique

• Levator palpebrae superioris

• Origin

• Mesencephalon

• Foramen

• Superior orbital fissure

• Destination

• Extra-ocular eye muscles


Figure 16.26 Cranial Nerves Controlling the Extra-Ocular Muscles


Superior

oblique

muscle

Trochlea

Levator

palpebrae

superioris

muscle

Inferior

oblique

muscle

Inferior

rectus

muscleCiliary

ganglion

Medial

rectus

muscle Lateral

rectus

muscle (cut)

ABDUCENS

NERVE (N VI)

Facial nerve

(N VII), cut

Vestibulocochlear

nerve (N VIII), cut

Trigeminal

nerve (N V), cut

Superior

rectus

muscle

OPTIC

NERVE (N II)

Optic

chiasm

OCULOMOTOR

NERVE (N III)

TROCHLEAR

NERVE (N IV)

The Cranial Nerves

• CN IV: The Trochlear Nerve

• Function

• Controls extra-ocular eye muscles

• Motor function

• Superior oblique

• Origin

• Mesencephalon

• Foramen


• Destination

• Superior oblique muscle




Superior

oblique

muscle

Trochlea

Levator

palpebrae

superioris

muscle

Inferior

oblique

muscle

Inferior

rectus

muscleCiliary

ganglion

Medial

rectus

muscle Lateral

rectus

muscle (cut)

ABDUCENS

NERVE (N VI)

Facial nerve

(N VII), cut

Vestibulocochlear

nerve (N VIII), cut

Trigeminal

nerve (N V), cut

Superior

rectus

muscle

OPTIC

NERVE (N II)

Optic

chiasm

OCULOMOTOR

NERVE (N III)

TROCHLEAR

NERVE (N IV)

The Cranial Nerves

• CN V: The Trigeminal Nerve

• Function

• Mixed (sensory and motor) function

• Ophthalmic: sensations from the forehead,

eyelids, and nose

• Maxillary: sensations from lower eyelid, upper lip,

and cheek

• Mandibular: controls mastication

• Origin

• Ophthalmic, maxillary, and mandibular nerves


Figure 16.27 The Trigeminal Nerve


Supraorbital

nerves

Ciliary ganglion

Foramen

rotundum

Infra-orbital

nerve

Lingual nerve

Mental nerve

Submandibular

ganglion

PonsTRIGEMINAL

NERVE (N V)

Maxillary branch

Foramen ovale

Otic ganglion

Mandibular branch

Pterygopalatine

ganglion

Superior

orbital

fissureOphthalmic

branch

Semilunar

ganglion

The Cranial Nerves

• CN V: The Trigeminal Nerve (continued)

• Foramen

• Ophthalmic: superior orbital fissure

• Maxillary: foramen rotundum

• Mandibular: foramen ovale

• Destination

• Ophthalmic and maxillary: Pons

• Mandibular: mandibular muscles


The Cranial Nerves

• CN VI: The Abducens Nerve

• Function

• Controls eye movements

• Motor function

• Origin

• Pons

• Foramen


• Destination

• Innervates the lateral rectus eye muscle




Superior

oblique

muscle

Trochlea

Levator

palpebrae

superioris

muscle

Inferior

oblique

muscle

Inferior

rectus

muscleCiliary

ganglion

Medial

rectus

muscle Lateral

rectus

muscle (cut)

ABDUCENS

NERVE (N VI)

Facial nerve

(N VII), cut

Vestibulocochlear

nerve (N VIII), cut

Trigeminal

nerve (N V), cut

Superior

rectus

muscle

OPTIC

NERVE (N II)

Optic

chiasm

OCULOMOTOR

NERVE (N III)

TROCHLEAR

NERVE (N IV)

The Cranial Nerves

• CN VII: The Facial Nerve

• Function

• Mixed (sensory and motor)

• Sensory: sensations from the face/taste

• Motor: controls muscles of the face

• Origin

• Sensory: taste buds

• Motor: pons


The Cranial Nerves

• CN VII: The Facial Nerve

• Foramen

• Internal acoustic meatus

• Destination

• Sensory: pons

• Motor: muscles of the face


Figure 16.28a The Facial Nerve


Pterygopalatine

ganglionGreater

petrosal

nerve

Geniculate

ganglion

FACIAL

NERVE (N VII)

Pons

Posterior auricular

branch

Stylomastoid

foramen

Chorda tympani nerve

(with mandibular

branch of N V)

Lingual branch

(with lingual nerve

of N V)

Submandibular

ganglion

Origin and branches of the facial nerve

Cervical

branch

Mandibular

branch

Buccal

branch

Zygomatic

branches

Temporal

branch

a

The Cranial Nerves

• CN VIII: The Vestibulocochlear Nerve

• Function

• Sensory: balance and hearing

• Origin

• Receptors of the vestibule and cochlea

• Foramen

• Internal acoustic meatus

• Destination

• Pons


Figure 16.29 The Vestibulocochlear Nerve (1 of 1)


Tympanic cavity

(middle ear)

Semicircular

canals

Vestibular

branch

(N VIII)

Facial nerve

(N VII), cut

Internal

acoustic

canal

VESTIBULOCOCHLEAR

NERVE (N VIII)

Pons

Medulla

oblongata

N V

N VIN VII

N IX

N XII

N X

N XI

Tympanic

membraneAuditory

tube

Cochlea Cochlear

branch (N VIII)

The Cranial Nerves

• CN IX: The Glossopharyngeal Nerve

• Function

• Mixed (sensory and motor)

• Sensory function: tongue pain

• Motor function: swallowing

• Origin

• Sensory: posterior 1/3 of the tongue

• Motor: salivary gland


The Cranial Nerves

• CN IX: The Glossopharyngeal Nerve (continued)

• Foramen

• Jugular foramen

• Destination

• Sensory: medulla oblongata

• Visceral motor: parotid salivary gland

• Somatic motor: pharyngeal muscles for swallowing


Figure 16.30 The Glossopharyngeal Nerve


N VI

N VII

N V

N VIII

Medulla oblongata

Pons

Superior (jugular) ganglion

Parotid salivary gland

Pharyngeal branches

Carotid sinus branch

Carotid sinus

Common carotid artery

Carotid body

GLOSSOPHARYNGEAL

NERVE (N IX)Otic

ganglion

Inferior

(petrosal)

ganglion

Lingual

branch

The Cranial Nerves

• CN X: The Vagus Nerve

• Function

• Sensory: information from organs

• Motor: sends information to the organs

• Origin

• Sensory: from the organs

• Motor: medulla oblongata


The Cranial Nerves

• CN X: The Vagus Nerve (continued)

• Foramen

• Jugular foramen

• Destination

• Sensory: autonomic centers of the medulla

oblongata

• Somatic motor: muscles of the palate and pharynx

• Visceral motor: respiratory, cardiovascular, and

digestive organs


Figure 16.31 The Vagus Nerve


VAGUS

NERVE (N X)

Superior

pharyngeal

branch

Inferior ganglion

of vagus nerve

Pons

Medulla oblongata

Auricular branch

to external ear

Superior ganglion

of vagus nerve

Pharyngeal branch

Superior laryngeal nerve

Cardiac branches

Cardiac plexus

Recurrent

laryngeal nerve

Right lung Left lung

LiverAnterior

vagal trunk

Spleen

Celiac

plexus

Small intestine

Hypogastric

plexus

Stomach

Pancreas

Colon

Internal branch

External branchSuperior

laryngeal nerve

The Cranial Nerves

• CN XI: The Accessory Nerve

• Function

• Motor: controls the sternocleidomastoid, trapezius,

palate, pharynx, and larynx muscles

• Origin

• Spinal cord and medulla oblongata


The Cranial Nerves

• CN XI: The Accessory Nerve

• Foramen

• Jugular foramen

• Destination

• Internal branch: muscles of the palate, pharynx,

and larynx

• External branch: sternocleidomastoid and trapezius

muscles


Figure 16.32 The Accessory and Hypoglossal Nerves



Medulla oblongata

Spinal cord

Trapezius muscle

Omohyoid muscle

Sternothyroid muscle

Sternohyoid muscle

Thyrohyoid muscle

Hyoid bone

Geniohyoid muscle

Hyoglossus muscle

Genioglossus muscle

Styloglossus muscle

Cranial root of N XI

HYPOGLOSSAL NERVE (N XII)

ACCESSORY NERVE (N XI)

Internal branch: to palatal,

pharyngeal, and laryngeal

muscles with vagus nerve

Intrinsic muscles

of tongue

Sternocleidomastoid

muscle

Ansa cervicalis

(cervical plexus)

External

branch of N XI

Spinal

root of N XI

The Cranial Nerves

• CN XII: The Hypoglossal Nerve

• Function

• Motor: controls tongue movement

• Origin


• Foramen

• Hypoglossal canal

• Destination

• Tongue muscles


Figure 16.32 The Accessory and Hypoglossal Nerves



Medulla oblongata

Spinal cord

Trapezius muscle

Omohyoid muscle

Sternothyroid muscle

Sternohyoid muscle

Thyrohyoid muscle

Hyoid bone

Geniohyoid muscle

Hyoglossus muscle

Genioglossus muscle

Styloglossus muscle

Cranial root of N XI

HYPOGLOSSAL NERVE (N XII)

ACCESSORY NERVE (N XI)

Internal branch: to palatal,

pharyngeal, and laryngeal

muscles with vagus nerve

Intrinsic muscles

of tongue

Sternocleidomastoid

muscle

Ansa cervicalis

(cervical plexus)

External

branch of N XI

Spinal

root of N XI

The Cranial Nerves

• Summary of Cranial Nerve Branches and

Functions

• Mnemonic aid

• Oh, Once One Takes The Anatomy Final, Very

Good Vacations Are Heavenly


Table 16.12 The Cranial Nerves (1 of 2)


Table 16.12 The Cranial Nerves (2 of 2)


Table 16.13 Cranial Reflexes


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