Introduction of Human Brain PowerPoint Presentation

Slide 1 -

1 Chapter 14The Central Nervous System The brain is a center for: 1. registering sensations 2. correlating with stored information 3. making decisions 4. taking action.

Slide 2 -

2 Landmarks Major parts of the brain - cerebrum, cerebellum, brainstem brain weighs about 3 pounds, more in anatomy students

Slide 3 -

3 Brain Longitudinal fissure separates 2 cerebral hemispheres Fissures are deep grooves sulci the shallow grooves gyri are the elevated folds surface layer of gray matter is called the cortex, squash, noodle

Slide 4 -

4 Cranial Meninges Dura mater -- outermost, tough membrane outer periosteal layer against bone forms dural venous sinuses draining blood from brain supportive structure formed by dura mater falx cerebri Arachnoid mater is spider web filamentous layer Pia mater is a thin vascular layer adherent to contours of brain The brain has a PAD around it that is continuous with the _____ ____

Slide 5 -

5 Cranial Meninges

Slide 6 -

6 Brain Ventricles Ventricles are Internal chambers within the CNS

Slide 7 -

7 Cerebrospinal Fluid Clear liquid fills ventricles and canals, it flows in the subarachnoid space Functions buoyancy -- floats brain so it neutrally buoyant protection -- cushions from hitting inside of skull chemical stability -- rinses away wastes

Slide 8 -

8 Flow of Cerebrospinal Fluid CSF is formed by the choroid plexuses and circulates through the: ventricles, down central canal of spinal cord to subarachnoid space of cord and brain, up to be absorbed by the arachnoid villi of the dural sinus

Slide 9 -

9 Clinical If CSF cannot circulate or drain properly a condition called hydro-cephalus (water on the brain) develops. fluid buildup causes increased pressure on the brain, either internally or externally Surgically draining the ventricles and diverting the flow of CSF by an implanted shunt reduces the pressure

Slide 10 -

10 Blood-Brain Barrier Most materials entering CSF from the blood cannot leak through the tight junctions between the surrounding ependymal cells permeable to lipid-soluble materials (alcohol, O2, CO2, nicotine and anesthetics) These constitute the Blood-Brain barrier, which permits certain substances to enter the fluid but excludes others thereby protecting the brain and spinal cord from harm

Slide 11 -

11 Brain Stem Medulla Pons Midbrain Etc.

Slide 12 -

12 Medulla Oblongata Cranial nerves (IX- XII) Heart rate, respiratory rate Adjusts blood vessel diameter Reflex centers for coughing, sneezing, gagging, swallowing, vomiting, and hiccupping.

Slide 13 -

13 Pons Anterior bulge in the brainstem Pathways between cerebellum Relays nerve impulses related to voluntary skeletal movements from the cerebral cortex to the cerebellum Cranial nerves V- VIII

Slide 14 -

14 CN III and IV eye movement Substantia nigra sends inhibitory signals to thalamus (degeneration leads to tremors of Parkinson disease) Midbrain

Slide 15 -

15 Cerebellum Connected to brainstem Arbor vitae (tree of life) visible in sagittal section Sits atop the 4th ventricle

Slide 16 -

16 Cerebellum The cerebellum functions in the coordination of skeletal muscle contractions and in the maintenance of normal muscle tone, posture, and balance. It compares motor output of the primary motor area to sensory data from body (proprioceptors, vision, cochlea, etc.)

Slide 17 -

17 Reticular Activating System (RAS) Throughout pons, midbrain & medulla Regulate balance & posture Regulates sleep & conscious attention injury leads to irreversible coma

Slide 18 -

18 Diencephalon Thalamus Pineal Gland Thalamus, Hypothalamus and Epithalamus (houses pineal gland). The pineal secretes melatonin to influence diurnal cycles.

Slide 19 -

19 THALAMUS Thalamus is located superior to the midbrain and serves as relay station for all sensory impulses, except smell, to the cerebral cortex 1) medial geniculate (hearing), 2) lateral geniculate (vision)

Slide 20 -

20 Hypothalamus Hypothalamus is found inferior to the thalamus Is a relay station for smell. Major regulators of homeostasis It controls and integrates the autonomic nervous system, which regulates contraction of smooth muscle, cardiac muscle, and secretions of many glands. Seat of rage & aggression, body temperature. hunger and the satiety, thirst, Maintains the waking state and sleep patterns

Slide 21 -

21 Frontal contains voluntary motor for planning, mood, smell and social judgement Motor is in FRONT of a car Parietal integrates it com-pairs Occipital is optical Temporal contains areas for hearing, emotional behavior, learning, memory, smell Functions of Cerebrum Lobes

Slide 22 -

22 Basal Nuclei (Basal Ganglia) Masses of gray matter deep to cerebral cortex Involved in motor control & inhibition of tremors Great names for new born

Slide 23 -

23 Limbic System Loop of cortical structures surrounding deep brain amygdala, hippocampus, fornix & cingulate gyrus Amydala important in emotions and hippocampus in memory – the rest we are not sure about

Slide 24 -

24 EEG and Brain Waves Electroencephalogram (EEG) graphs brain waves May be used to diagnose epilepsy and other seizure disorders It may also provide useful information regarding sleep and wakefulness. Can diagnosis brain death (two EEGs 24 hours apart)

Slide 25 -

25 Accidental Lobotomy of Phineas Gage Accidental destruction of both frontal lobes Personality change to an irreverent, profane person Neuroscientists believe planning, moral judgement, and emotional control are functions of the frontal lobe

Slide 26 -

26 Memory Information management requires learning, memory & forgetting (eliminating the trivia) anterograde amnesia -- can not store new data retrograde amnesia -- can not remember old data Hippocampus is important in organizing sensory & cognitive information into a memory lesion to it causes inability to form new memories Cerebellum helps learn motor skills Amygdala important in emotional memory

Slide 27 -

27 Sensory Homunculus Demonstrates that the area of the cortex dedicated to the sensations of various body parts is proportional to how sensitive that part of the body is.

Slide 28 -

28 Motor Homunculus

Slide 29 -

29 Language Includes reading, writing, speaking & understanding words Wernicke’s area permits recognition of spoken & written language Broca’s area generates motor program for larynx, tongue, cheeks & lips transmits that to primary motor cortex for action The Gnostic area (parietal lobe) integrates sensory interpretations with memories from most of the brain to formulate a common thought and devise a single response to the incoming information.

Slide 30 -

30 Language Centers

Slide 31 -

31 Aphasia An impairment of the ability to use or comprehend words usually due to stroke or brain injury. Lesions in Wernicke’s & Broca’s areas (usually on the left) are common types: Lesion to Broca’s = Motor (nonfluent) aphasia they know what they want to say but can’t say it Inability to coordinate the muscles controlling speech (Your Boca Broka?) Lesion to Wernicke’s = fluent aphasia words are easily spoken but those used are incorrect (Words are key) Anatomic aphasia (Inability to recognize anatomy) = temporary affliction of anatomy professors

Slide 32 -

32 PET Scans during a Language Task

Slide 33 -

33 Cerebral Lateralization Left hemisphere is categorical hemisphere specialized for spoken & written language, math & science Right hemisphere is representational hemisphere perceives information more holistically, music and artistic skill Highly correlated with handedness 91% of people right-handed with left side is categorical Lateralization develops with age trauma more problems in males since females have more communication between hemisphere (corpus callosum is thicker posteriorly)

Slide 34 -

34 CRANIAL NERVES 12 pairs of nerves from the brain

Slide 35 -

35 Numbering the Nerves In classic anatomy we use Roman numerals to number the cranial nerves: I is one, II is two, III is three, IV is four, V is five, VI is six, VII is seven, VIII is eight, IX is nine, X is ten, XI is eleven and XII is twelve The modern way of numbering the cranial nerves is by using CN followed by an Arabic number. For example: VIII is written CN 8.

Slide 36 -

36 I - Olfactory Nerve Provides sense of smell Damage causes impaired sense of smell Test with coffee grounds, spice not perfume, Why? Test for smell NOT recognition of smell. (Ch. 16)

Slide 37 -

37 II - Optic Nerve Provides vision Damage causes blindness in visual field

Slide 38 -

38 III - Oculomotor Nerve Provides eye movement, opening of eyelid Damage causes ptosis (drooping eyelid), double vision

Slide 39 -

39 IV - Trochlear Nerve Moves eye down and out Damage causes double vision & inability to look down and out

Slide 40 -

40 VI - Abducens Nerve Moves eye laterally (ABduction) Damage results in inability to move eye ______

Slide 41 -

41 Innervation of Eye Muscles

Slide 42 -

42 V - Trigeminal Nerve Main sensory nerve to face (touch, pain and temperature) and muscles of mastication Damage produces loss of sensation & impaired chewing or can cause increased pain = trigeminal neuralgia

Slide 43 -

43 VII - Facial Nerve Provides facial expressions, sense of taste on anterior 2/3’s of tongue, salivary glands and tear, nasal & palatine glands Damage produces sagging facial muscles & disturbed sense of taste (missing sweet & salty) called Bell’s Palsy

Slide 44 -

44 VIII - Vestibulocochlear Nerve Provides hearing & sense of balance Damage produces deafness, dizziness, nausea, loss of balance & nystagmus

Slide 45 -

45 IX - Glossopharyngeal Nerve Provides control over swallowing, salivation, gagging, sensations from posterior 1/3 of tongue, control of BP and respiration Damage results in loss of bitter & sour taste & impaired swallowing.

Slide 46 -

46 X - Vagus Nerve The wonderer Provides swallowing, speech, regulation of 2/3 of GI tract Damage causes impaired voice, swallowing and digestion

Slide 47 -

47 XI - Accessory Nerve Contracts upper trap muscles (I don’t know) Damage causes impaired shoulder movement

Slide 48 -

48 XII - Hypoglossal Nerve Provides tongue movements of speech, food manipulation & swallowing Damage results in inability to protrude tongue, TEST – Stick tongue out and it points right then the _____ XII is broken

Slide 49 -

49 CN 1- 12 (Summary)(Know the number and the nerve) On Old Olympus Towering Tops A Famous Vocal German Viewed Some Hops CN 1- Smells like an old factory. CN2- Two eyes see CN 3, 4, 6- moves the eyes CN 5- Trigeminal, three finger on face CN7- Facial, closes eye lids CN 8 Vestibulocochlear, ear CN 9 Glossopharyngeal, G looks like a nine CN 10 Vagus, two Vs CN 11 Accessory- Trapezius muscle, shoulders up CN 12 Hypoglossal

Slide 50 -

50 Cranial Nerves function Some cranial nerves (I, II, and VIII) contain only sensory fibers. The rest are mixed nerves because they contain both sensory and motor fibers.

Slide 51 -

51 CLINICAL Conditions related to the brain and nervous system

Slide 52 -

52 Brain Trauma Lapse in memory is one of many effects resulting from brain injuries Commonly associated with head injuries Various degrees of brain injury are described by the terms; 1) concussion (temporary consciousness and or memory loss), 2) contusion (brain bruising, with longer term losses), and 3) laceration (brain tissue tearing with intracranial bleeding and increased pressure).

Slide 53 -

53 TIA (Transient Ischemic Attack) An episode of temporary cerebral dysfunction caused by impaired blood flow to the brain. Symptoms include: dizziness, weakness, numbness, or paralysis in a limb or in half of the body, drooping of one side of the face, loss of vision or double vision. Onset is sudden and a TIA usually persists for only a few minutes, rarely lasting as long as 24 hours. Causes: blood clots, atherosclerosis TIAs commonly are forerunners of future CVAs.

Slide 54 -

54 CVAs(Brain heart attack) 1. CVAs (Cerebral Vascular Accidents) are classified into two principal types: a. ischemic (the most common type), due to a decreased blood supply, or b. hemorrhagic, due to a blood vessel in the brain that bursts. 2. Common causes of CVAs are; a. intracerebral hemorrhage, b. emboli, and c. atherosclerosis. 3. CVAs are characterized by abrupt onset of persisting neurological symptoms that arise from destruction of brain tissue (infarction).

Slide 55 -

55 Headache Causes: Vertebral subluxation and: Brain tumors, blood vessel abnormalities, inflammation of the brain or meninges, decrease in oxygen supply to the brain, damage to brain cells, and infections of the eyes, ears, nose, or sinuses, Tension headaches are associated with stress, fatigue, and anxiety and usually occur in the occipital and temporal muscles Migraine headaches sometimes respond to drugs that constrict the blood vessels

Slide 56 -

56 Brain tumor Any benign or malignant growth within the cranium. Symptoms from the increased intracranial pressure from the growing tumor or accompanying edema, and can include; headaches, altered consciousness, vomiting, seizures, visual problems, cranial nerve abnormalities, hormonal syndromes, personality changes, dementia, and sensory or motor deficits.

Slide 57 -

57 Cerebral palsy (CP) Refers to a group of motor disorders resulting in muscular in coordination and loss of muscle control. Caused by damage to the motor areas of the brain during fetal life, birth, or infancy. This damage may result from; a. German measles infection of the mother during the first trimester, b. radiation during gestation, c. temporary lack of oxygen during birth, or d. hydrocephalus during infancy.

Slide 58 -

58 Dyslexia Impairment of the brain's ability to translate images received from the eyes into understandable language. Reads IUD as DUI Causes seem related to lack of proper development i.e. crawling Treatment: cross crawl exercise

Slide 59 -

59 Cerebellar Impairment ATAXIA: uncoordinated and jerky movements, slurred speech INTENTION TREMOR- shaking during voluntary movement TEST: Finger to nose, finger to finger, tandem walk FIELD TRIP CEREBELLUM damage Tour of Ft. Lauderdale’s _______