Chapter 19

Anatomy of the Brain and Cranial Nerves 1 The Nervous System can be divided in: Central Nervous System (CNS) Brain and Spinal Cord Peripheral Nervous System (PNS)

Cranial and spinal nerves, ganglia, sensory receptors 2 Division of the Peripheral Nervous System Sensory or afferent Somatic Visceral

Motor or efferent Somatic - voluntary Visceral or Autonomic Nervous System (ANS) - involuntary Sympathetic Parasympathetic 3 Major regions and landmarks Six regions in the adult brain

Cerebrum Diencephalon Mesencephalon Pons Cerebellum Medulla oblongata Brain contains extensive areas of neural cortex Layer of gray matter on the surface of the cerebellum and cerebrum 4

The Cerebrum 5 The cerebral hemispheres Surface contains gyri, sulci, fissures Fissures Longitudinal fissure separates two cerebral hemispheres

Transverse fissure separates cerebellum from cerebrum 6 The Cerebrum 7 The cerebral hemispheres

Sulci Parieto-occipital sulcus separates parietal from occipital lobe Lateral sulcus separates temporal from parietal lobe Central sulcus separates frontal and parietal lobe 8

The cerebral hemispheres Gyri Precentral gyrus Poscentral gyrus 9 The cerebral lobes Frontal

Precentral gyrus Primary motor area conscious control of voluntary movements. Premotor cortex memory bank for skilled motor activities or of patterned and repetitious nature. Brocas area Located on the left hemisphere. Controls speech. 10

The cerebral lobes Prefrontal cortex responsible for personality, cognition, intellect. Lesion cause mental and personality disorder Parietal Primary Somatosensory Area touch, pressure, temperature, vibration, and pain from body wall Somatosensory association area interprets

stimulus sent by the above area. Ex: recognizes objects by touch. 11 The cerebral lobes Temporal Primary Auditory area temporal lobe. Primary association auditory area interprets the sound heard by above area Wernickes area only on left hemisphere,

between parietal and temporal lobes. Area responsible for understanding spoken language Olfactory area uncus. Smell area. 12 The cerebral lobes Occipital Primary visual area perception of light Visual association area interprets the

images seen on the area above Insula Gustatory cortex 13 Cerebral hemispheres - internal structures Gray matter Cell bodies of the neurons

Dendrites Small unmyelinated axons Neuroglias 14 Cerebral hemispheres - internal structures White matter Tracts

Association connects 2 areas of the same hemisphere Projection connects upper and lower brain. Ex: internal capsule Commissure connects the 2 hemispheres. 15 Tracts

16 Sagittal Section 17 Cerebral hemispheres - internal structures Corpus callosum Connects the 2 hemispheres

Fornix Connects limbic system areas Septum pellucidum Separates the 2 lateral ventricles 18 Cerebral hemispheres - internal structures Basal Nuclei regulation of voluntary motor

activities. Allows smooth movements. Caudate Nucleus Putamen Globus pallidus 19 The Diencephalon 20

21 22 Diencephalon: external view Olfactory tract Olfactory bulb Optic nerve Chiasma optic

Pituitary gland or hypophysis Mammilary bodies relay for olfaction 23 The diencephalon is composed of Epithalamus Hypothalamus Thalamus

24 Sagittal Section 25 Figure 14.12b The Epithalamus Roof of the third ventricle

Contains choroid plexus Contains pineal gland Regulates sleep-awake cycle 26 The thalamus Relay area for impulses Two large lobes of gray matter Interthalamic adhesion or intermediate mass

27 The hypothalamus Autonomic center for regulation of body temperature, water balance, etc Secretes hormones Mammilary bodies relay station for olfaction Pituitary glands secretes hormones

Optic chiasm 28 The Brain Stem Midbrain Cerebral Aqueduct connects third and forth ventricles Cerebral peduncles connects pons to cerebrum

Corpora quadrigemina Superior colliculi visual reflex center Inferior colliculi auditory reflex center 29 The Brain Stem Pons Consists of tracts and nuclei Connects brain to lower CNS Medulla Oblongata

Tracts Decussation of the pyramids Autonomic reflex centers heart rate, blood pressure, vomiting, swallowing, respiratory rhythm Olives 30 PART 2

31 Cerebellum Two hemispheres connected by the vermis Arbor vitae white matter Cortex of gray matter 32

The Cerebellum 33 The Cerebellum 34 The cranial meninges Dura mater

Falx cerebri-formed by dura mater that dips into the longitudinal fissure and separates the 2 hemispheres Falx cerebelli separate the two cerebellar hemispheres 35 The cranial meninges dura mater

Superior sagittal Sinus collects blood from the brain Tentorium cerebelli separates the cerebrum from the cerebellum 36 The cranial meninges Arachnoid Subarachnoid space

Filled with CSF Arachnoid villi projections of the mater that protrude through the dura For the CSF to drain back to the venous circulation 37 The cranial meninges

Pia mater Highly vascular Covers the entire brain Meningites 38 The Relationship among the Brain, Cranium, and Meninges

39 Ventricles of the brain Filled with cerebrospinal fluid (CSF) Lateral ventricles Septum pellucidum Interventricular foramina or foramen of Monro 40

Ventricles of the brain Third ventricle Cerebral aqueduct Forth ventricle 3 Apertures 41

Ventricles of the Brain 42 Cerebrospinal fluid (CSF) CSF cushions delicate neural structures Supports the brain Pathway of CSF Produced at the Choroid plexus Travels through the apertures on the 4th

ventricle to the subarachnoid space Diffuses across the arachnoid villus (granulation) into the superior sagittal sinus 43 The Circulation of CSF 44 Cranial Nerves

12 pairs of cranial nerves To help to remember Old Opie Occasionally Tries Trigonometry And Fells Very Gloomy Vague And Hypoactive 45 The Cranial Nerves PLAY

46 Cranial Nerves Number I II III IV V

Name Olfactory (sens) Optic (sens) Oculomotor (mot) Trochlear (mot) Trigeminal (mix) Major Functions Smell

Vision Eye movement Eye movement Chewing muscles, head and face sensation 47 Cranial nerves VI

Abducens (mot) Eye movement VII Facial (mix) Face expression,

taste VIII Vestibulocochlear (sen) Vestibular: posture and balance Cochlear: hearing

48 Cranial Nerves IX X Glossopharynge al (mix) Vagus (mix)

XI Accessory (mot) XII Hypoglossal (mot)

Swallowing, taste, general sensation for pharynx Visceral muscle movement and taste sensation Swallowing, and head movement Movement of tongue for speaking, swallowing and mixing food

49 Brain Dissection Whole Brain Pia-Arachnoid Gyrus Sulcus Fissure Transverse Longitudinal

Cerebrum 50 Brain Dissection Pons Medulla Oblongata Cerebellum Cranial nerves: I (bulb, tract) II (nerve, chiasma)

III 51 Brain Dissection Colliculi Superior Inferior Pineal Gland 52

Brain Dissection Sagittal Cut Diencephalon Epithalamus Thalamus Hypothalamus Ventricles Lateral, third, forth 53

Brain Dissection Septum pellucidum Corpus callosum Fornix Arbor vitae (cerebellum) 54