Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 1 Protection of CNS

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Brain  3 lbs  About the size of two fists  Wrinkled  Not solid- kind of mushy to the touch  Highly vasculated

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 3 Blood supply & Nutrition Brain is highly vascular blood delivers O 2 and glucose supply and carries away wastes Brain cells have no capacity for anaerobic respiration. They cannot be O 2 deprived Brain cells die w/in 5-6 minutes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 4 Protection 1. Bone Cranial bones & vertebral arches 2. Meninges Dura mater Arachnoid mater Pia mater 3. Cerebrospinal fluid (CSF)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 5 Meninges 3 Layers Dura mater (made of two membranes) Arachnoid mater Pia mater

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Dura Mater “Tough Mother” Thick, leathery outer covering Support, and forms sinus system (where blood drains and returns to the heart) Pain sensitive Has own blood supply – Middle meningeal artery

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Dura Mater

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Arachnoid Spongy/fibrous layer between the dura and pia connective tissue forms projections which give it a spider-web appearance Forms Subarachnoid space Contains CSF

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Pia Mater Innermost layer Adheres almost indistinguishably to cortical surface, including sulci and gyri Difficult to see grossly or remove

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 3 Layers of Meninges

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrospinal Fluid Produced from blood plasma in choroid plexuses Located in the subarachnoid space Cushions CNS - like waterbed Nourishes brain tissue

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrospinal Fluid Returned to blood at superior sagittal sinus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 13 Blood-brain barrier Capillaries in the choroid plexus have thicker walls (than capillaries found elsewhere). This means less molecules can passively diffuse into the CSF Most molecules must be actively transported (therefore, they are “selected” to enter) Protects brain from drugs, metabolites, toxins

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 14 Ventricles of the Brain 2 Lateral ventricles (1, 2) in cerebral hemispheres Third ventricle (3) between hemispheres (under the fornix) Cerebral aquaduct connects the 3 rd and 4th Fourth ventricle (4) in midbrain and medulla

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of the Brain 4 Major Regions of the Brain

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 1. Cerebrum or Cerebral Hemisphere 1. Cerebral Hemispheres (Cerebrum)  Paired superior parts of the brain  Largest part: includes more than half of the brain mass

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  The surface is made of ridges (gyri or 1 gyrus) and grooves (sulci or 1 sulcus)  Deeper grooves called fissures exist  Longitudinal fissure: separates the right and left hemisphere of the cerebrum

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum 4 Lobes of the cerebrum (on each hemisphere)  Lobes are named based on the cranial bones that lie over them  Surface lobes of the cerebrum 1. Frontal lobe 2. Parietal lobe 3. Occipital lobe 4. Temporal lobe Lateral sulcus Central sulcus *Parietooccipital sulcus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Specialized areas of the Cerebrum  Cerebral Cortex:  outer layer of the cerebrum (grey matter/cell bodies)  Processing of information occurs here  Labeled A  There are also “islands” of grey matter known as basal nuclei *label B shows white matter/ neural axons- relaying of information occurs here

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum Corpus callosum connects the two cerebral hemispheres  It is a nerve tract (bundle of nerves having the same origin and destination)  Necessary for communication between the two hemisperes  Corpus callosotomy- cuts the corpus callosum to interrupt the spread of seizures, makes them less severe.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum: Cerebral Cortex (right side controls left side- vice versa)  Postcentral gyrus Primary somatic sensory area: receives impulses from the body’s sensory receptors (pain, cold, etc)  Precentral gyrus Primary motor area  Sends impulses to consciously move skeletal muscles  Premotor area  Stores sequence activities Pre motor area

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum: Cerebral Cortex: Frontal Lobe Association cortex: involved in planning, complex ideas, behaviors, concentration, ability to focus, emotional traits, judgment and inhibition Broca’s area: Involved in our ability to speak Asymmetric (only on left hemisphere)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum: Cerebral Cortex: Parietal Lobe Association cortex: receive and utilize information from the lower levels of the brain: temperature,taste, touch, and movement from the rest of the body – such as distance and position of objects

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum: Cerebral Cortex: Temporal Lobe Important for making new memories, and for short- term memory, including memories of taste, sound, sight, and touch Wernicke’s Area responsible for receiving auditory information and recognizing words; it is thus central to the process of learning and understanding language.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cerebrum: Cerebral Cortex: Occipital Lobe primary visual center of the brain, processes information from the eyes, and links that information with images stored in memory. In other words, this area helps you determine what you are looking at.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: 2. Diencephalon  Sits on top of the brain stem  Enclosed by the cerebral hemispheres  Made of three parts (shown in yellow on brain model) 1.Thalamus 2.Hypothalamus (posterior to optic chiasma) 3. Epithalamus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Diencephalon 1.Thalamus The relay station for sensory impulses  Transfers impulses to the correct part of the cerebral cortex for localization and interpretation

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon 2. Hypothalamus (posterior to optic chiasma)  stimulates and controls structures such as the heart, most glands and smooth muscles  allows your systems to excite and relax, as needed. Examples:  Regulate body temperature  Controls water balance  Regulates metabolism  Drive/emotion, sex, appetite, thirst

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Hypothalamus The pituitary gland is attached to the hypothalamus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Diencephalon 3.Epithalamus Location of pineal body primarily responsible for melatonin cycles Includes the choroid plexus bundle of capillaries that form cerebrospinal fluid

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 3. Brain Stem  Attaches to the spinal cord Parts of the brain stem A. Midbrain B. Pons C. Medulla oblongata

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Brain Stem A. Midbrain Tracts of nerve fibers  Reflex centers for vision and hearing  Send messages to and from cerebrum  Connect the third and fourth ventricles- cerebral aquaduct

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Brain Stem B. Pons  The bulging center part of the brain stem  Mostly composed of fiber tracts  Controls breathing

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Brain Stem C. Medulla Oblongata  The lowest part of the brain stem  Merges into the spinal cord  Involuntary control center  Heart rate control  Blood pressure regulation  Breathing/Coughing  Swallowing/Gagging  Vomiting

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings 4. Cerebellum  Two hemispheres with convoluted surfaces (like the cerebrum)  Provides involuntary coordination of body movements (fine motor skills and smooth movements)  Balance/Coordination  Monitors body position