2The Brain ~35 billion neurons Adult brain contains almost 98% of neural tissue in the bodyWeighs about 1.4 kg (3lbs)Volume of 1200 cc (71 in3)No correlation between brain size and intelligence
3Three Main Structures1. Cerebrum2. Cerebellum3. Brain Stem
4The Cerebrum Conscious thought and intellectual function originate B. Outer Surface composed of:a. Gyri- elevated ridges (increase surface area)b. Sulci- shallow depressionsc. Fissures- deep groovesC. Two Cerebral Hemispheres covered by a cerebral cortex1. Right Hemisphere2. Left Hemisphere~Hemispheres are united by a corpus callosum- major route of communication between the hemispheres.
6Hemisphere Control Right Side judging the position of things in space knowing body positionunderstanding and remembering things we do and seeputting bits of information together to make an entire picturecontrols the left side of the bodyLeft Sideunderstanding and use of language (listening, reading, speaking and writing)memory for spoken and written messagesdetailed analysis of informationcontrols the right side of the body
7LEFT BRAIN DAMAGE Problems seen on the right side of the body. RIGHT BRAIN DAMAGE Problems seen on the left side of the body.
8Cerebral HemispheresSeparated by a deep longitudinal fissure (central sulcus extends laterally)Divided into lobes named for bones of the skull:Frontal LobeTemporal LobeParietal LobeOccipital Lobe
9Frontal Lobe Primary Motor Cortex: - voluntary motor function problem solvingSpontaneityMemoryLanguageJudgmentimpulse controlPersonalityVulnerable to injury
10Parietal Lobe Primary Sensory Cortex: - sensory somatic information Location for visual attention.Location for touch perception.Goal directed voluntary movements.Manipulation of objects.Integration of different senses that allows for understanding a single concept.
11Temporal Lobe Hearing ability Memory acquisition Some visual perceptionsCategorization of objectsAuditory Cortex- hearingOlfactory Cortex- smelling
12Occipital Lobe Visual Cortex - Vision ~not particularly vulnerable to injury because of their location at the back of the brain~although any significant trauma to the brain could produce subtle changes to our visual-perceptual system
13The Limbic SystemContains several cerebral nuclei, gyri, and tracts that border the cerebrum and the diencephalon.Contains cerebral centers concerned with:1. sense of smell2. long-term memory storage- Hippocampus3. emotional states (flight and fight)- Amygdaloid4. control of reflex movements that can be consciously activated
14Diencephalon (Forebrain) Central Core of the forebrainSwitching and relay centers that integrate the conscious and unconscious sensory and motor pathways.Composed of the:1. Thalamus2. Hypothalamus3. Epithalamus
16Thalamus Constitutes the top of the brain stem Paired egg shaped massesAfferent impulses from all senses converge and synapse in the thalamusImpulses are sorted out, edited, and relayed as a groupCoordination of voluntary and involuntary motor commandsPlays an important role in mediating sensation, motor activities, learning and memory.
18Hypothalamus Located between the thalamus Contains centers associated with emotions of rage, pleasure, pain, thirst, hunger, and sexual arousal1. Adjusts and coordinates the activities of autonomic centers in the pons and medula oblongata2. Coordinates neural and endocrine activities3. Produces a variety of hormones including antidiuretic hormone (ADH) and oxytocin4. Coordinates voluntary and autonomic functions5. Maintains normal body temperature6. Regulates sleep, sleep cycle, hunger, blood pressure, heart rate, breathing depth
20EpithalamusPineal gland: extends from the posterior border and secretes melatonin- involved in sleep regulation, and moodChoroid plexus- structure that secretes CSF (cerebrospinal fluid)
21Midbrain Located between the diencephalon and the pons Midbrain structures include:1. various nuclei and buncles of ascending and descending nerve fibers.2. control involuntary motor reflexes to sudden visual and auditory stimuli (loud noise, bright light)Reticular Formation- network of interconnected nuclei that extend the length of the brain stem.- regulation of involuntary functions-maintains position and posture
23Pons (Hindbrain)Bulging brainstem region between the midbrain and the medulla oblongataFibers of the pons:Connect higher brain centers and the spinal cordRelay impulses between the motor cortex and the cerebellum
25Medulla Oblongata Most inferior part of the brain stem Physically connects the brain with the spinal cordCardiovascular control center- adjusts force and rate of heart contraction.Respiratory centers- control rate and depth of breathing
27CerebellumMakes rapid adjustments to muscle tone and position to maintain balance and equilibriumPrograms and fine-tunes voluntary and involuntary movementsPlays a role in language and problem solvingRecognizes and predicts sequences of eventsMaybe permanently damaged by stroke or temporarily affected by alcohol
28Gray Matter Adjusts the postural muscles of the body: Coordinates rapid automatic adjustments to maintain balance and equilibriumPrograms and “fine-tunes” voluntary and involuntary movements- refines learned movements patterns
29White MatterArbor Vitae- (tree of life) which links Cerebellar cortex (gray matter) to the-1. Cerebellar Peduncles-which link the cerebellum to themesencephalondiencephaloncerebrumTransverse fibersLike the commissural fibers in the cerebrum- link the cerebellar hemispheres and extend into the pons and medulla oblongata.