Fundamentals of Anatomy & Physiology

Fundamentals of Anatomy & Physiology
Eleventh Edition Chapter 14 The Brain and Cranial Nerves Lecture Presentation by Deborah A. Hutchinson Seattle University

Learning Outcomes 14-1 Name the major brain regions, vesicles, and ventricles, and describe the locations and functions of each Explain how the brain is protected and supported, and discuss the formation, circulation, and function of cerebrospinal fluid Describe the anatomical differences between the medulla oblongata and the spinal cord, and identify the main components and functions of the medulla oblongata List the main components of the pons, and specify the functions of each List the main components of the midbrain, and specify the functions of each.

Learning Outcomes 14-6 List the main components of the cerebellum, and specify the functions of each List the main components of the diencephalon, and specify the functions of each Identify the main components of the limbic system, and specify the locations and functions of each Identify the major anatomical subdivisions and functions of the cerebrum, and discuss the origin and significance of the major types of brain waves seen in an electroencephalogram Describe representative examples of cranial reflexes that produce somatic responses or visceral responses to specific stimuli.

Introduction to the Brain and Cranial Nerves
Adult human brain Contains almost 97 percent of body’s nervous tissue Average weight is 1.4 kg (3 lb) Volume is typically 1200 mL Ranges from 750 to 2100 mL in functionally normal individuals Brains of males are about 10 percent larger than those of females No correlation between brain size and intelligence

14-1 The Brain Regions of the brain Cerebrum Cerebellum Diencephalon
Brainstem

a Cerebrum b Cerebellum Left cerebral hemisphere Gyri Sulci
Figure 14–1 An Introduction to Brain Structures and Functions (Part 1 of 2). Left cerebral hemisphere Gyri a Cerebrum Sulci Conscious thought processes, intellectual functions Memory storage and processing Conscious and subconscious regulation of skeletal muscle contractions Fissures b Cerebellum Coordinates complex somatic motor patterns Adjusts output of other somatic motor centers in brain and spinal cord Spinal cord

14-1 The Brain Cerebrum Largest part of adult brain
Controls higher mental functions Conscious thoughts, intellect, memory, etc. Divided into left and right cerebral hemispheres

14-1 The Brain Cerebral cortex of cerebrum
Surface layer of gray matter Rounded elevations (gyri) increase surface area Gyri are separated by Shallow depressions (sulci) or Deep grooves (fissures)

14-1 The Brain Cerebellum Second-largest part of brain
Coordinates repetitive body movements Two hemispheres Covered by gray matter (cerebellar cortex)

14-1 The Brain Diencephalon Located under cerebrum and cerebellum
Thalamus Relays and processes sensory information Hypothalamus is involved with Emotions Autonomic function Hormone production

14-1 The Brain Diencephalon Pituitary gland Major endocrine gland
Connected to hypothalamus via infundibulum (stalk) Integrates nervous and endocrine systems

14-1 The Brain Brainstem Relays information between spinal cord and cerebrum or cerebellum Includes Midbrain Pons Medulla oblongata

14-1 The Brain Midbrain Processes sight, sound, and associated reflexes Maintains consciousness Pons Connects cerebellum to brainstem Contains Tracts (collections of CNS axons) Relay centers Nuclei for somatic and visceral motor control

14-1 The Brain Medulla oblongata Connects brain to spinal cord
Inferior portion has a narrow central canal Relays sensory information Regulates autonomic functions Heart rate, blood pressure, and digestion

Diencephalon Midbrain Pons Medulla oblongata c d e f Thalamus
Figure 14–1 An Introduction to Brain Structures and Functions (Part 2 of 2). c Diencephalon Thalamus Relays and processes sensory information Hypothalamus Controls emotions, autonomic functions, and hormone production d Brainstem Midbrain Processes visual and auditory data Generates reflexive somatic motor responses Maintains consciousness e Pons Relays sensory information to cerebellum and thalamus Subconscious somatic and visceral motor centers f Medulla oblongata Relays sensory information to thalamus and to other portions of the brainstem Autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities)

14-1 The Brain Embryonic development
Determines organization of brain structures Neural tube Develops into CNS Rostral portion enlarges to form three primary brain vesicles Prosencephalon (“forebrain”) Mesencephalon (“midbrain”) Rhombencephalon (“hindbrain”)

14-1 The Brain Secondary brain vesicles Telencephalon Diencephalon
Mesencephalon Metencephalon Myelencephalon

14-1 The Brain Origins of brain structures
Diencephalon and mesencephalon persist Telencephalon Forms cerebrum Metencephalon Forms cerebellum and pons Myelencephalon Forms medulla oblongata

Table 14–1 Development of the Brain

14-1 The Brain Ventricles of the brain
In the embryo, neural tube encloses neurocoel Neurocoel expands to form chambers (ventricles) lined with ependymal cells Each cerebral hemisphere contains one large lateral ventricle Separated by medial partition (septum pellucidum) Third ventricle in diencephalon Communicates with each lateral ventricle Via interventricular foramen

14-1 The Brain Ventricles of the brain Fourth ventricle
Extends into medulla oblongata Joins central canal of spinal cord Connects with third ventricle Via narrow canal in midbrain (cerebral aqueduct)

Figure 14–2a Ventricular System.
Cerebral hemispheres Ventricular System of the Brain Lateral ventricles Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Pons Medulla oblongata Spinal cord Central canal a a Ventricular system, lateral view

Figure 14–2b Ventricular System.
Cerebral hemispheres Ventricular System of the Brain Lateral ventricles Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle Central canal Cerebellum b Ventricular system, anterior view

14-2 Brain Protection and Support
Physical protection of the brain Bones of the cranium Cranial meninges Cerebrospinal fluid Biochemical isolation Blood brain barrier

Cranial meninges Have three layers Dura mater Arachnoid mater Pia mater Continuous with spinal meninges

Cranial meninges Dura mater Inner fibrous layer (meningeal cranial dura) Outer fibrous layer (periosteal cranial dura) Fused to periosteum

Dural folds Extensions of meningeal cranial dura into cranial cavity Stabilize and support brain Contain collecting veins (dural venous sinuses) Three largest dural folds Falx cerebri Tentorium cerebelli Falx cerebelli

Falx cerebri Projects between cerebral hemispheres Contains superior sagittal sinus and inferior sagittal sinus Tentorium cerebelli Separates cerebrum from cerebellum Contains transverse sinus Falx cerebelli Divides cerebellar hemispheres below the tentorium cerebelli

Cranial meninges Arachnoid mater Covers brain In life, it attaches to dura mater May be separated by subdural space Subarachnoid space lies between arachnoid mater and pia mater Pia mater Attached to brain surface by astrocytes

A lateral view of the brain, showing its position in
Figure 14–3a The Relationships among the Brain, Cranium, and Cranial Meninges. Cranium Periosteal cranial dura Dura mater Dural sinus Meningeal cranial dura Subarachnoid space Pia mater Subdural space Cerebral cortex Arachnoid mater Cerebrum Cerebellum Medulla oblongata Spinal cord a A lateral view of the brain, showing its position in the cranium and the organization of the meninges

A diagrammatic view, showing the orientation of the three largest
Figure 14–3b The Relationships among the Brain, Cranium, and Cranial Meninges. Dura mater Superior sagittal sinus Cranium Inferior sagittal sinus Dural folds Falx cerebri Tentorium cerebelli Falx cerebelli Transverse sinus b A diagrammatic view, showing the orientation of the three largest dural folds: the falx cerebri, tentorium cerebelli, and falx cerebelli

Cerebrospinal fluid (CSF) Surrounds all exposed surfaces of CNS Functions to Support brain Cushion delicate neural structures Transport nutrients, chemical messengers, and wastes

Choroid plexus produces CSF Specialized ependymal cells surround capillaries Secretes about 500 mL of CSF into ventricles per day Removes waste products from CSF Adjusts composition of CSF

CSF circulates From choroid plexus Through ventricles To central canal of spinal cord Into subarachnoid space Via two lateral apertures and one median aperture in roof of fourth ventricle To surround brain, spinal cord, and cauda equina

Arachnoid villi Extensions of arachnoid membrane Extend through meningeal layer of dura mater into superior sagittal sinus Arachnoid granulations Large clusters of arachnoid villi in adults Absorb CSF into venous circulation

Choroid plexus of third ventricle Choroid 2 plexus of fourth ventricle
Figure 14–4 Formation and Circulation of Cerebrospinal Fluid (Part 2 of 3). Choroid plexus of third ventricle Choroid plexus of fourth ventricle 2 The CSF circulates from the choroid plexus through the ventricles and fills the central canal of the spinal cord. As it circulates, materials diffuse between the CSF and the interstitial fluid of the CNS across the ependymal cells. 3 The CSF reaches the subarachnoid space through two lateral apertures and a single median aperture in the roof of the fourth ventricle. Spinal cord Central canal 4 Dura mater Cerebrospinal fluid then flows through the subarachnoid space surrounding the brain, spinal cord, and cauda equina. Conus medullaris Arachnoid mater Cauda equina Filum terminale

1 The choroid plexus produces and maintains CSF.
Figure 14–4 Formation and Circulation of Cerebrospinal Fluid (Part 1 of 3). Nutrients, O2 Interstitial fluid in thalamus Capillaries Wastes, CO2 Neuron Astrocyte Choroid plexus ependymal cells 1 Ependymal cells The choroid plexus produces and maintains CSF. Two extensive folds of the choroid plexus originate in the roof of the third ventricle and extend through the interventricular foramina. These folds cover the floors of the lateral ventricles. In the inferior brainstem, a region of the choroid plexus in the roof of the fourth ventricle projects between the cerebellum and the pons. Removal of waste Production of CSF Cerebrospinal fluid in third ventricle Tight junction Choroid plexus

5 Dura mater (periosteal layer) Arachnoid granulation Arachnoid
Figure 14–4 Formation and Circulation of Cerebrospinal Fluid (Part 3 of 3). Dura mater (periosteal layer) Arachnoid granulation Arachnoid trabecula Cranium CSF fluid movement Superior sagittal sinus Dura mater (meningeal layer) Subdural space Arachnoid mater Cerebral cortex Subarachnoid space Pia mater 5 Fingerlike extensions of the arachnoid membrane, called the arachnoid villi, penetrate the meningeal layer of the dura mater and extend into the superior sagittal sinus. In adults, these extensions form large arachnoid granulations. CSF is absorbed into the venous circulation at the arachnoid granulations.

Protective function of cranial meninges and CSF Dural folds hold brain in position Protect it from damage that would result from contact with cranium CSF cushions brain against sudden jolts Cranial trauma Head injury resulting from impact with an object

Blood supply to the brain Internal carotid arteries and vertebral arteries Deliver nutrients and oxygen Most blood is removed from dural venous sinuses by internal jugular veins

Cerebrovascular diseases Disorders that interfere with blood supply to brain Cerebrovascular accident (CVA) or stroke Stops blood flow to a portion of the brain Affected neurons begin to die within minutes

Blood brain barrier (BBB) Isolates CNS from general circulation Formed by network of tight junctions Between capillary endothelial cells in CNS Generally, only lipid-soluble compounds like O2, CO2, steroids, prostaglandins, and small alcohols Can diffuse into interstitial fluid of CNS Astrocytes regulate blood brain barrier by Releasing chemicals that control permeability of endothelium

Blood CSF barrier Formed by specialized ependymal cells connected by tight junctions That surround capillaries of choroid plexus Limits transfer of substances to CSF Allows chemical composition of blood and CSF to differ

Breaks in the BBB Portions of hypothalamus Allows hypothalamic hormones into circulation Posterior lobe of pituitary gland Allows ADH and oxytocin into circulation Pineal gland Allows pineal secretions into circulation Choroid plexus Where specialized ependymal cells maintain blood CSF barrier

14-3 The Medulla Oblongata
Most inferior part of brainstem Coordinates complex autonomic reflexes Includes three groups of nuclei Control visceral functions Sensory and motor nuclei of CNS Relay stations for communication between brain and spinal cord

Figure 14–5a The Diencephalon and Brainstem.
Cerebral peduncle Thalamus Lateral geniculate nucleus Optic tract Medial geniculate nucleus Cranial Nerves Midbrain II Superior colliculus Inferior colliculus III IV Cerebellar Peduncles Superior cerebellar peduncle V Pons Middle cerebellar peduncle VI VII Inferior cerebellar peduncle VIII IX X Medulla oblongata XI XII Spinal nerve C1 Spinal nerve C2 Spinal cord a Lateral view

Figure 14–5b The Diencephalon and Brainstem.
Optic chiasm Infundibulum Cranial Nerves Thalamus II Optic tract III Cerebral peduncle IV Mammillary body V Pons VI VII VIII IX X XI XII Medulla oblongata Ventral roots of spinal nerves C1 and C2 Spinal cord b Anterior view

Figure 14–5c The Diencephalon and Brainstem.
Choroid plexus in third and fourth ventricles Thalamus Third ventricle Pineal gland Corpora Quadrigemina Superior colliculi Inferior colliculi CN IV Cerebral peduncle Cerebellar Peduncles Superior Middle Choroid plexus in roof of fourth ventricle Inferior Posterior roots of spinal nerves C1 and C2 c Posterior view

Figure 14–5d The Diencephalon and Brainstem.
Thalamus Third ventricle Pineal gland Corpora Quadrigemina Superior colliculi Inferior colliculi Cerebral peduncle Trochlear nerve (IV) Cerebellar Peduncles Superior Middle Inferior Fourth ventricle d Posterior view, cadaver dissection

Reflex centers: autonomic and reflex activity Reticular formation Gray and white matter with embedded nuclei Regulates autonomic functions Cardiovascular centers Cardiac and vasomotor centers Control blood flow through peripheral tissues Respiratory rhythmicity centers Set pace for respiratory movements

Sensory and motor nuclei of cranial nerves Associated with 5 cranial nerves (VIII, IX, X, XI, XII)

Relay stations along sensory and motor pathways Gracile nucleus and cuneate nucleus Pass somatic sensory information to thalamus Tracts leaving nuclei cross to opposite side of brain at decussation of pyramids Solitary nuclei Receive visceral sensory information Inferior olivary complex Bulk of olivary nuclei creates the olives Relay information about somatic motor commands

Figure 14–6a The Medulla Oblongata.
Autonomic Centers Reticular formation Cardiovascular centers Medulla oblongata Solitary nuclei Pons Relay Stations Olivary nucleus Inferior olive Pyramids Cuneate nucleus Spinal cord Gracile nucleus Decussation of pyramids Lateral white columns a Anterior view

Figure 14–6b The Medulla Oblongata.
Attachments to membranous roof of fourth ventricle Posterior median sulcus Lateral funiculus Posterior funiculi b Posterolateral view

14-4 The Pons Pons contains Sensory and motor nuclei of cranial nerves
Nuclei involved with respiration Apneustic center and pneumotaxic center Nuclei and tracts that process and relay information sent to or from cerebellum Ascending, descending, and transverse pontine fibers Transverse pontine fibers (axons) link nuclei of pons with opposite cerebellar hemisphere

Pons Cerebellum Fourth ventricle Medulla oblongata Spinal cord
Figure 14–7 The Pons. Pons Cerebellum Fourth ventricle Medulla oblongata Spinal cord Inferior olivary nucleus

14-5 The Midbrain Structures of the midbrain Tectum
Two pairs of sensory nuclei (corpora quadrigemina) Superior colliculi (visual) Inferior colliculi (auditory) Tegmentum Red nucleus (many blood vessels) Substantia nigra (pigmented gray matter)

14-5 The Midbrain Structures of the midbrain Cerebral peduncles
Nerve fiber bundles on ventrolateral surfaces Contain Descending fibers to cerebellum Descending motor command fibers

colored only on the right.
Figure 14–8a The Midbrain. Pineal gland Thalamus a A posterior view. The underlying nuclei are colored only on the right.

b Posterior view of a cadaver dissection
Figure 14–8b The Midbrain. Corpora Quadrigemina Thalamus Superior colliculi Inferior colliculi Cerebral peduncle Trochlear nerve (IV) Superior cerebellar peduncle Fourth ventricle b Posterior view of a cadaver dissection of the diencephalon and brainstem.

c A superior view of a transverse section
Figure 14–8c The Midbrain. Tectum (roof) ANTERIOR Cerebellum Superior colliculus Cerebral aqueduct Tegmentum Red nucleus Substantia nigra Cerebral peduncle POSTERIOR c A superior view of a transverse section at the level of the midbrain.

14-6 The Cerebellum Structures of the cerebellum Cerebellar cortex
Gray matter of highly convoluted surface Folia Folds in cerebellar cortex Anterior and posterior lobes Separated by primary fissure Cerebellar hemispheres

14-6 The Cerebellum Structures of the cerebellum Vermis (“worm”)
Narrow band of cortex Separates cerebellar hemispheres at midline Flocculonodular lobe Lies above roof of fourth ventricle

14-6 The Cerebellum Structures of the cerebellum Purkinje cell layer
Consists of large, branched neuron cell bodies In cerebellar cortex Each cell receives input from up to 200,000 synapses Arbor vitae (“tree of life”) Highly branched, internal white matter of cerebellum Cerebellar nuclei embedded in arbor vitae Relay information to Purkinje cells

14-6 The Cerebellum Functions of the cerebellum are to
Adjust postural muscles Program and fine-tune conscious and subconscious movements

14-6 The Cerebellum Cerebellar peduncles
Tracts that link cerebellum with brainstem, cerebrum, and spinal cord leave the cerebellum as Superior cerebellar peduncles Middle cerebellar peduncles Inferior cerebellar peduncles

14-6 The Cerebellum Disorders of the cerebellum Ataxia
Disturbance in muscular coordination Caused by Damage from trauma or stroke Intoxication (temporary impairment)

Figure 14–9a The Cerebellum (Part 1 of 2).
Vermis Anterior lobe Primary fissure Folia Posterior lobe Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum a The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions

Figure 14–9a The Cerebellum (Part 2 of 2).
Vermis Anterior lobe Primary fissure Folia Posterior lobe Left Hemisphere of Cerebellum Right Hemisphere of Cerebellum a The posterior, superior surface of the cerebellum, showing major anatomical landmarks and regions

Figure 14–9b The Cerebellum (Part 1 of 2).
Anterior lobe Midbrain Choroid plexus of the fourth ventricle Pons Flocculonodular lobe Medulla oblongata Posterior lobe b A sectional view of the cerebellum, showing the arrangement of gray matter and white matter

Figure 14–9b The Cerebellum (Part 2 of 2).
Dendrites Cell body of Purkinje cell Purkinje cells LM × 100 b A sectional view of the cerebellum, showing the arrangement of gray matter and white matter

14-7 The Diencephalon Diencephalon
Integrates sensory information with motor commands Epithalamus, thalamus, and hypothalamus Pineal gland In posterior portion of epithalamus Secretes melatonin

14-7 The Diencephalon Thalamus Filters and relays sensory information
From spinal cord and cranial nerves To cerebral cortex Relays information between basal nuclei and cerebral cortex The third ventricle separates left and right sides Interthalamic adhesion Projection of gray matter Extends into third ventricle on each side

14-7 The Diencephalon Thalamic nuclei
Relay sensory information to basal nuclei and cerebral cortex Five groups of thalamic nuclei Anterior nuclei of thalamus Part of limbic system (emotions) Medial nuclei of thalamus Provide awareness of emotional states Ventral nuclei of thalamus Relay sensory information to cerebral cortex

14-7 The Diencephalon Five groups of thalamic nuclei
Dorsal nuclei of thalamus Pulvinar nuclei (sensory) Geniculate bodies Lateral geniculate body (visual) Medial geniculate body (auditory) Affects emotional states

view of the brain, color coded to indicate the regions that
Figure 14–10a The Thalamus. Frontal lobe Parietal lobe Occipital lobe a A lateral view of the brain, color coded to indicate the regions that receive input from the thalamic nuclei shown in part b

b An enlarged view of the thalamic nuclei of the left side Limbic
Figure 14–10b The Thalamus. Limbic system Frontal lobes Parietal lobe and cingulate gyrus Association areas of cerebral cortex Medial nuclei Anterior nuclei Lateral nuclei Pulvinar Ventral nuclei Auditory input Medial geniculate body Basal nuclei General sensory input Lateral geniculate body Visual input Cerebellum b An enlarged view of the thalamic nuclei of the left side

Table 14–2 The Thalamus

14-7 The Diencephalon Hypothalamus Mammillary bodies
Control reflex eating movements Infundibulum A narrow stalk Connects hypothalamus to pituitary gland Tuber cinereum Between infundibulum and mammillary bodies Produces hormones that affect pituitary gland

Figure 14–11a The Hypothalamus in Sagittal Section.
Parietal lobe Corpus callosum Choroid plexus Septum pellucidum Thalamus (surrounds third ventricle) Fornix Anterior cerebral artery Pineal gland Hypothalamus Frontal lobe Cerebral aqueduct Anterior commissure Cerebellum Optic chiasm Fourth ventricle Optic nerve Infundibulum (cut) Tuber cinereum Mammillary body a The hypothalamus and adjacent portions of the brain

Figure 14–11b The Hypothalamus in Sagittal Section.
Interthalamic adhesion Thalamus Hypothalamus Tuber cinereum Optic chiasm Mid- brain Infundibulum Pituitary gland Pons b A diagram of the hypothalamus, showing the locations and functions of major nuclei and centers

14-7 The Diencephalon Eight functions of hypothalamus
Secretes ADH (supra-optic nucleus) and oxytocin (paraventricular nucleus) Regulates body temperature Pre-optic area Controls autonomic function Coordinates voluntary and autonomic functions Coordinates nervous and endocrine systems

14-7 The Diencephalon Eight functions of hypothalamus
Regulates circadian rhythms (day–night cycles) Suprachiasmatic nucleus Subconscious control of skeletal muscle Produces emotions and behavioral drives Feeding center (hunger) Thirst center (thirst) Satiety center (regulates food intake)

14-8 The Limbic System Limbic system Functional grouping that
Establishes emotional states Links conscious functions of cerebral cortex with autonomic functions of brainstem Facilitates memory storage and retrieval

14-8 The Limbic System Components of the limbic system
Limbic lobe of cerebral hemisphere Cingulate gyrus Dentate gyrus Parahippocampal gyrus Hippocampus Amygdaloid body Acts as interface between the limbic system, cerebrum, and various sensory systems

14-8 The Limbic System Components of the limbic system Fornix
Tract of white matter Connects hippocampus with hypothalamus Anterior nuclei of thalamus Relay information from mammillary body to cingulate gyrus Reticular formation Alertness, excitement, lethargy, and sleep

Figure 14–12a The Limbic System.
Corpus callosum Pineal gland Fornix Cingulate gyrus (superior portion of limbic lobe) Anterior thalamic nuclei Parahippocampal gyrus (inferior portion of limbic lobe) Hypothalamus Mammillary body Hippocampus (within dentate gyrus, the posterior portion of limbic lobe) Temporal lobe of cerebrum a A diagrammatic sagittal section through the cerebrum, showing the cortical areas associated with the limbic system. The parahippocampal gyrus is shown as though transparent to make deeper limbic components visible.

Figure 14–12b The Limbic System.
Corpus callosum Olfactory tract b A three-dimensional reconstruction of the limbic system, showing the relationships among the major components.

14-9 The Cerebrum Cerebrum Largest part of brain
Controls all conscious thoughts and intellectual functions Processes somatic sensory and motor information Gray matter In cerebral cortex and basal nuclei White matter Deep to cerebral cortex Around basal nuclei

14-9 The Cerebrum Structures of the cerebrum Gyri of cerebral cortex
Increase surface area available for cortical neurons Longitudinal cerebral fissure Separates cerebral hemispheres Lobes Regions of hemispheres

14-9 The Cerebrum Structures of the cerebrum Central sulcus divides
Anterior frontal lobe from posterior parietal lobe Precentral gyrus of frontal lobe Forms anterior border of central sulcus Postcentral gyrus of parietal lobe Forms posterior border of central sulcus

14-9 The Cerebrum Structures of the cerebrum Lateral sulcus
Separates frontal lobe from temporal lobe Insula (“island” of cortex) Lies medial to lateral sulcus Parieto-occipital sulcus Separates parietal lobe from occipital lobe

Figure 14–13a The Brain in Lateral View.
Central sulcus Frontal lobe Parietal lobe Occipital lobe Lateral sulcus Cerebellum Temporal lobe Pons Medulla oblongata a Lateral view, cadaver brain

Figure 14–13b The Brain in Lateral View.
Precentral gyrus Central sulcus Postcentral gyrus Frontal lobe Parietal lobe Occipital lobe Temporal lobe Lateral sulcus Cerebellum Pons Medulla oblongata b Lateral view

Figure 14–13c The Brain in Lateral View.
Insula c Retractors along the lateral sulcus showing the insula

Figure 14–13d The Brain in Lateral View.
Precentral gyrus Central sulcus Postcentral gyrus Cingulate gyrus Parietal lobe Frontal lobe Parieto- occipital sulcus Occipital lobe Pons Temporal lobe Cerebellum Medulla oblongata d Midsagittal section

14-9 The Cerebrum White matter of the cerebrum Association fibers
Form connections within one hemisphere Arcuate fibers Short fibers Connect one gyrus to another Longitudinal fasciculi Longer bundles Connect frontal lobe to other lobes in same hemisphere

14-9 The Cerebrum White matter of the cerebrum Commissural fibers
Bands of fibers connecting two hemispheres Corpus callosum Anterior commissure

14-9 The Cerebrum White matter of the cerebrum Projection fibers
Link cerebral cortex to diencephalon, brainstem, cerebellum, and spinal cord Pass through diencephalon Internal capsule All ascending and descending projection fibers

Figure 14–14a Fibers of the White Matter of the Cerebrum.
Lateral view

Figure 14–14b Fibers of the White Matter of the Cerebrum.
Longitudinal cerebral fissure Internal capsule b Anterior view

14-9 The Cerebrum Basal nuclei Masses of gray matter
Embedded in white matter of cerebrum Direct subconscious activities

14-9 The Cerebrum Basal nuclei Caudate nucleus
Large head and slender, curving tail Lentiform nucleus Putamen (lateral) Globus pallidus (medial) Claustrum Thin layer of gray matter close to putamen

Figure 14–15a The Basal Nuclei.
Head of caudate nucleus Lentiform nucleus Tail of caudate nucleus Thalamus Amygdaloid body a The relative positions of the basal nuclei in the intact brain, lateral view

Figure 14–15b The Basal Nuclei.
Corpus callosum Lateral ventricle (anterior horn) Head of caudate nucleus Septum pellucidum Internal capsule Fornix (cut edge) Putamen Thalamus Third ventricle Choroid plexus Pineal gland Fornix Lateral ventricle (posterior horn) b A superior view of two transverse sections at different levels

Figure 14–15c The Basal Nuclei.
Corpus callosum Lateral ventricle Septum pellucidum Internal capsule Lateral sulcus Insula Anterior commissure Claustrum Tip of inferior horn of lateral ventricle Amygdaloid body c Frontal section

14-9 The Cerebrum Functions of basal nuclei
Subconscious control of skeletal muscle tone Coordination of learned movement patterns (walking, lifting) Parkinson’s disease Symptoms are caused by increased activity of basal nuclei

14-9 The Cerebrum Functional principles of the cerebrum
Cortex of each cerebral hemisphere Receives somatosensory information from And sends motor commands to The opposite side of the body Correspondence between a specific function and a specific area of the cerebral cortex is imprecise

14-9 The Cerebrum Central sulcus separates motor and sensory areas
Motor areas Primary motor cortex Surface of precentral gyrus Pyramidal cells Neurons of primary motor cortex Sensory areas Primary somatosensory cortex Surface of postcentral gyrus

14-9 The Cerebrum Special sensory cortices Visual cortex
Receives visual information Auditory cortex Receives information about hearing Olfactory cortex Receives information about smell Gustatory cortex Receives information from taste receptors

14-9 The Cerebrum Association areas
Connected to sensory and motor regions of cortex Interpret incoming data or coordinate a motor response Premotor cortex Also called somatic motor association area Coordinates learned movements

14-9 The Cerebrum Sensory association areas
Somatosensory association cortex Monitors activity in primary somatosensory cortex Example: it recognizes touch Visual association area Interprets activity in visual cortex Auditory association area Monitors auditory cortex

Major anatomical landmarks on the surface of
Figure 14–16a Motor, Sensory, and Association Areas of the Cerebral Cortex. Central sulcus Parietal Lobe Frontal Lobe Primary somatosensory cortex Primary motor cortex Premotor cortex Somatosensory association cortex Retractor Occipital Lobe Prefrontal cortex Visual association area Visual cortex Gustatory cortex Insula Temporal Lobe Lateral sulcus Auditory association area Auditory cortex Olfactory cortex a Major anatomical landmarks on the surface of the left cerebral hemisphere. The lateral sulcus has been pulled apart to expose the insula.

Table 14–3 The Cerebral Cortex

14-9 The Cerebrum Integrative centers
In lobes and cortical areas of both cerebral hemispheres Receive information from association areas Direct complex motor activities Perform analytical functions

14-9 The Cerebrum Wernicke’s area Language comprehension
Primarily associated with left cerebral hemisphere Receives information from sensory association areas Coordinates access to visual and auditory memories

14-9 The Cerebrum Broca’s area (motor speech area) Speech production
Primarily associated with left cerebral hemisphere Regulates patterns of breathing and vocalization

14-9 The Cerebrum Prefrontal cortex of frontal lobe
Coordinates information relayed from all cortical association areas Performs abstract intellectual functions Example: predicting consequences of actions Prefrontal lobotomy Used to “cure” mental illnesses in mid-20th century

The left hemisphere generally contains the specialized
Figure 14–16b Motor, Sensory, and Association Areas of the Cerebral Cortex. Frontal eye field Broca’s area Wernicke’s area Prefrontal cortex b The left hemisphere generally contains the specialized language areas. The prefrontal cortex of each hemisphere is involved with conscious intellectual functions.

14-9 The Cerebrum Hemispheric lateralization
Functional differences between left and right cerebral hemispheres Each performs certain functions that are not ordinarily performed by the opposite hemisphere

14-9 The Cerebrum Left cerebral hemisphere Reading, writing, and math
Speech and language Decision making Right cerebral hemisphere Analyzes sensory information Example: touch, smell, sight, taste Recognition of faces and voice inflections

14-9 The Cerebrum Brain activity
Assessed with an electroencephalogram (EEG) Electrodes are placed on brain or skull Electrical patterns (brain waves) are observed Types of typical brain waves Alpha waves Beta waves Theta waves Delta waves

14-9 The Cerebrum Alpha waves
Seen in healthy, awake adults at rest with eyes closed Beta waves Higher-frequency waves Seen in adults who are concentrating or mentally stressed

Alpha waves are characteristic of normal resting adults a Seconds 1 2
Figure 14–17a Brain Waves. a Alpha waves are characteristic of normal resting adults Seconds 1 2 3 4

Beta waves typically accompany intense concentration b Seconds 1 2 3 4
Figure 14–17b Brain Waves. b Beta waves typically accompany intense concentration Seconds 1 2 3 4

14-9 The Cerebrum Theta waves
Seen in children and in intensely frustrated adults May indicate brain disorder in adults Delta waves Large-amplitude, low-frequency waves Occur during sleep, in infants, and in awake adults with brain damage

Theta waves are seen in children and in frustrated adults c Seconds 1
Figure 14–17c Brain Waves. c Theta waves are seen in children and in frustrated adults Seconds 1 2 3 4

Delta waves occur in deep sleep and in certain pathological conditions
Figure 14–17d Brain Waves. d Delta waves occur in deep sleep and in certain pathological conditions Seconds 1 2 3 4

14-9 The Cerebrum Synchronization of electrical activity between hemispheres Achieved through a “pacemaker” mechanism Desynchronization may result from injury or tumor Seizure A temporary cerebral disorder Accompanied by changes in electrical activity Symptoms depend on region of cortex affected

14-10 Cranial Nerves Cranial nerves 12 pairs connected to brain
Classifications of cranial nerves Primarily sensory: carriers of somatic sensory information including touch, pressure, vibration, temperature, and pain Special sensory: carriers of sensations such as smell, sight, hearing, and balance Motor: axons of somatic motor neurons Mixed: sensory and motor fibers

14-10 Cranial Nerves Cranial nerves
Are classified by primary functions May also have important secondary functions Several distribute autonomic fibers to peripheral ganglia

Figure 14–18 Origins of the Cranial Nerves (Part 1 of 2).
Olfactory tract Optic chiasm Infundibulum Optic tract Mammillary body Basilar artery Pons Vertebral artery Medulla oblongata Cerebellum Spinal cord

Figure 14–18 Origins of the Cranial Nerves (Part 2 of 2).
Olfactory bulb: termination of olfactory nerve (I) Optic nerve (II) Oculomotor nerve (III) Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve (VI) Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Hypoglossal nerve (XII) Accessory nerve (XI)

14-10 Cranial Nerves Olfactory nerves (I) Primary function
Special sensory (smell) Origin Receptors of olfactory epithelium Pass through Olfactory foramina in cribriform plate of ethmoid Destination Olfactory bulbs

14-10 Cranial Nerves Olfactory nerve structures Olfactory bulbs
Located on either side of crista galli Olfactory tracts Axons of postsynaptic neurons Leading to cerebrum

Figure 14–19 The Olfactory Nerve.
Olfactory tract (to olfactory cortex of cerebrum) Left olfactory bulb (termination of olfactory nerve) Olfactory nerve (I) Olfactory nerve fibers Cribriform plate of ethmoid Olfactory epithelium

14-10 Cranial Nerves Optic nerves (II) Primary function
Special sensory (vision) Origin Retina of eye Pass through Optic canals of sphenoid Destination Diencephalon via optic chiasm

14-10 Cranial Nerves Optic nerve structures Optic chiasm
Where optic nerves converge At ventral, anterior margin of diencephalon Some fibers cross to opposite side of brain Optic tracts Reorganized axons Continue to lateral geniculate body of thalamus

Figure 14–20 The Optic Nerve.
Eye Pituitary gland Olfactory bulb Olfactory tract Optic nerve (II) Optic chiasm Optic tract Lateral geniculate body (in thalamus) Midbrain (cut) Visual cortex (in occipital lobes) Optic projection fibers

14-10 Cranial Nerves Oculomotor nerves (III) Primary function
Motor (eye movements) Origin Midbrain Pass through Superior orbital fissures of sphenoid

14-10 Cranial Nerves Oculomotor nerves (III) Destination Somatic motor
Superior, inferior, and medial rectus muscles Inferior oblique Levator palpebrae superioris Visceral motor Intrinsic eye muscles

14-10 Cranial Nerves Oculomotor nerves (III)
Each controls four of six eye-movement muscles Deliver autonomic fibers to neurons of ciliary ganglion These neurons control intrinsic eye muscles

14-10 Cranial Nerves Trochlear nerves (IV) Primary function
Motor (eye movements) Origin Midbrain Pass through Superior orbital fissures of sphenoid Destination Superior oblique

14-10 Cranial Nerves Abducens nerves (VI) Primary function
Motor (eye movements) Origin Pons Pass through Superior orbital fissures of sphenoid Destination Lateral rectus

Figure 14–21 Cranial Nerves Controlling the Extrinsic Eye Muscles.
Optic nerve (II) Optic chiasm Oculomotor nerve (III) Trochlear nerve (IV) Superior rectus Superior oblique Trochlea Levator palpebrae superioris Trigeminal nerve (V), cut Inferior oblique Vestibulocochlear nerve (VIII), cut Facial nerve (VII), cut Inferior rectus Ciliary ganglion Medial rectus Lateral rectus (cut) Abducens nerve (VI)

14-10 Cranial Nerves Trigeminal nerves (V) Primary function
Mixed (sensory and motor) of face Origin Ophthalmic nerve (V1) (sensory) Orbital structures Nasal cavity Skin of forehead, upper eyelid, and eyebrow Part of nose

14-10 Cranial Nerves Trigeminal nerves (V) Origin
Maxillary nerve (V2) (sensory) Lower eyelid Upper lip, gums, and teeth Cheek and nose Palate and part of pharynx

14-10 Cranial Nerves Trigeminal nerves (V) Origin
Mandibular nerve (V3) (sensory) Lower gums, teeth, and lips Palate and part of tongue Mandibular nerve (V3) (motor) Motor nuclei of pons

14-10 Cranial Nerves Trigeminal nerves (V) Pass through (on each side)
Ophthalmic nerve Superior orbital fissure Maxillary nerve Foramen rotundum Mandibular nerve Foramen ovale

14-10 Cranial Nerves Trigeminal nerves (V) Destination Sensory fibers
Sensory nuclei in pons Motor fibers of mandibular nerve Muscles of mastication

14-10 Cranial Nerves Trigeminal nerves (V) Largest cranial nerves
Three major divisions Semilunar ganglion Contains cell bodies of sensory neurons Tic douloureux (trigeminal neuralgia) Painful condition affecting area innervated by maxillary and mandibular divisions

Figure 14–22 The Trigeminal Nerve.
Superior orbital fissure Ophthalmic nerve (V1) Supra-orbital nerves Semilunar ganglion Ciliary ganglion Pons Trigeminal nerve (V) Foramen rotundum Maxillary nerve (V2) Infra-orbital nerve Foramen ovale Otic ganglion Lingual nerve Submandibular ganglion Mandibular nerve (V3) Pterygopalatine ganglion Mental nerve

14-10 Cranial Nerves Facial nerves (VII) Primary function
Mixed (sensory and motor) of face Origin Sensory Taste receptors on anterior two-thirds of tongue Motor Motor nuclei of pons Pass through Internal acoustic meatus to stylomastoid foramina

14-10 Cranial Nerves Facial nerves (VII) Destination Sensory
Sensory nuclei of pons Somatic motor Muscles of facial expression Visceral motor Lacrimal gland and nasal mucous glands Submandibular and sublingual glands

14-10 Cranial Nerves Facial nerve branches Temporal Zygomatic Buccal
Marginal mandibular Cervical

14-10 Cranial Nerves Facial nerve structures Geniculate ganglia
Contain cell bodies of sensory neurons Pterygopalatine ganglia Postganglionic fibers innervate lacrimal glands and glands of nasal cavity and pharynx Submandibular ganglia Innervate submandibular and sublingual glands

14-10 Cranial Nerves Bell’s palsy
Cranial nerve disorder resulting from inflammation of facial nerve Likely due to viral infection Signs and symptoms Paralysis of facial muscles on affected side Loss of taste sensations from anterior two-thirds of tongue Typically, symptoms fade after weeks or months

Figure 14–23a The Facial Nerve.
Pterygopalatine ganglion Greater petrosal nerve Geniculate ganglion Facial nerve (VII) Temporal branch Pons Zygomatic branches Posterior auricular nerve Buccal branch Stylomastoid foramen Marginal mandibular branch Chorda tympani with mandibular nerve Lingual branch with lingual nerve Cervical branch Submandibular ganglion a The origin and branches of the facial nerve

Figure 14–23b The Facial Nerve.
Temporal branches Zygomatic branches Buccal branches Marginal mandibular branch Cervical branch b The superficial distribution of the five major branches of the facial nerve

14-10 Cranial Nerves Vestibulocochlear nerves (VIII) Primary function
Special sensory Vestibular nerve Balance and equilibrium Cochlear nerve Hearing

14-10 Cranial Nerves Vestibulocochlear nerves (VIII) Origin
Receptors of internal ear Pass through Internal acoustic meatus of temporal bones Destination Vestibular and cochlear nuclei of pons and medulla oblongata

14-10 Cranial Nerves Vestibulocochlear nerve structures
Vestibular nerve Originates at receptors of vestibule (balance) Connects to vestibular nuclei of pons and medulla oblongata Cochlear nerve Monitors receptors in cochlea (hearing) Connects with cochlear nuclei of pons and medulla oblongata

Figure 14–24 The Vestibulocochlear Nerve.
Tympanic cavity (middle ear) Semicircular canals Vestibular nerve Facial nerve (VII), cut Internal acoustic meatus Vestibulocochlear nerve (VIII) CN V Pons CN VI CN VII CN IX CN XII CN X Medulla oblongata CN XI Tympanic membrane Auditory tube Cochlea Cochlear nerve

14-10 Cranial Nerves Glossopharyngeal nerves (IX) Primary function
Mixed (sensory and motor) of head and neck Origin Sensory Posterior one-third of tongue Part of pharynx and palate Carotid arteries Motor Motor nuclei of medulla oblongata

14-10 Cranial Nerves Glossopharyngeal nerves (IX) Pass through
Jugular foramina between occipital, temporal bones Destination Sensory Sensory nuclei of medulla oblongata Somatic motor Pharyngeal muscles involved in swallowing Visceral motor Parotid gland

14-10 Cranial Nerves Glossopharyngeal nerve structures
Superior ganglion and inferior ganglion Contain sensory neurons of tongue, pharynx, etc. Otic ganglion Where visceral motor fibers synapse

Figure 14–25 The Glossopharyngeal Nerve.
Pons CN V CN VII CN VIII CN VI Glossopharyngeal nerve (IX) Otic ganglion Medulla oblongata Inferior (petrosal) ganglion Superior (jugular) ganglion Pharyngeal branches Lingual branch Parotid gland Carotid branch Carotid body Carotid sinus Common carotid artery

14-10 Cranial Nerves Vagus nerves (X) Primary function
Mixed (sensory and motor) Widely distributed in thorax and abdomen

14-10 Cranial Nerves Vagus nerves (X) Origin Sensory Part of pharynx
Auricle and external acoustic meatus Diaphragm Visceral organs in thoracic and abdominopelvic cavities Motor Motor nuclei in medulla oblongata

14-10 Cranial Nerves Vagus nerves (X) Pass through
Jugular foramina between occipital bone and temporal bones

14-10 Cranial Nerves Vagus nerves (X) Destination Sensory
Sensory nuclei and autonomic centers of medulla oblongata Visceral motor Muscles of palate and pharynx Muscles of digestive, respiratory, and cardiovascular systems in thoracic and abdominal cavities

14-10 Cranial Nerves Vagus nerves (X) Branch and radiate extensively
Superior ganglion and inferior ganglion Contain sensory neurons

Figure 14–26 The Vagus Nerve (Part 1 of 2).
Pharyngeal branch Vagus nerve (X) Pons Medulla oblongata Auricular branch to external ear Superior ganglion of vagus nerve Inferior ganglion of vagus nerve Pharyngeal branch Superior laryngeal nerve Internal branch Superior laryngeal nerve External branch

Figure 14–26 The Vagus Nerve (Part 2 of 2).
Recurrent laryngeal nerve Cardiac branches Cardiac plexus Right lung Left lung Liver Anterior vagal trunk Spleen Stomach Celiac plexus Pancreas Colon Small intestine Hypogastric plexus

14-10 Cranial Nerves Accessory nerves (XI) Primary function
Motor to muscles of neck and upper back Origin Motor nuclei of spinal cord and medulla oblongata

14-10 Cranial Nerves Accessory nerves (XI) Pass through
Jugular foramina between occipital bone and temporal bones Destination Internal branch Voluntary muscles of palate, pharynx, and larynx External branch Sternocleidomastoid and trapezius

14-10 Cranial Nerves Accessory nerve structures Spinal root
Contains motor fibers that originate in anterior gray horns of first five cervical segments of spinal cord Cranial root Contains motor fibers that originate in medulla oblongata

14-10 Cranial Nerves Accessory nerve structures Internal branch
Joins vagus nerve Innervates voluntary swallowing muscles and muscles of vocal cords External branch Controls sternocleidomastoid and trapezius

14-10 Cranial Nerves Hypoglossal nerves (XII) Primary function
Motor (tongue movements) Origin Motor nuclei of medulla oblongata Pass through Hypoglossal canals of occipital bone Destination Muscles of tongue

Figure 14–27 The Accessory and Hypoglossal Nerves.
Hypoglossal nerve (XII) Trigeminal nerve (V) Accessory nerve (XI) Medulla oblongata Cranial root of CN XI Internal branch: to palatal, pharyngeal, and laryngeal muscles with vagus nerve Intrinsic muscles of tongue Spinal root of CN XI Styloglossus External branch of CN XI Genioglossus Geniohyoid Spinal cord Hyoglossus Hyoid bone Trapezius Thyrohyoid Sternocleidomastoid Sternohyoid Ansa cervicalis (cervical plexus) Sternothyroid Omohyoid

14-10 Cranial Nerves Cranial reflexes
Monosynaptic and polysynaptic reflex arcs Involve sensory and motor fibers of cranial nerves Clinically useful to check condition of cranial nerves and parts of brain

Fundamentals of Anatomy & Physiology

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Fundamentals of Anatomy & Physiology

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