2. brain spine

3. Introduction The brain is a complex three-dimensional structure that performs a bewildering array of functions However, the brain is far more versatile than a computer The brain is far more complex than the spinal cord The brain consists of roughly 20 billion neurons

4. Skull Part of Axial Skeleton Cranial bones = cranium – Enclose and protect brain – Attachment for head + neck muscles Facial bones =framework of face – Form cavities for sense organs – Opening for air + food passage – Hold teeth – Anchor face muscles

5. The Brain 4 Parts – Cerebrum – Diencephalon – Brain Stem Pons Medulla Midbrain – Cerebellum Gray matter surrounded by White matter

8. Major Parts of the Brain Brain stem- continuation of the spinal cord; consists of the medulla oblongata, Pons and midbrain. Cerebellum- second largest part of the brain. Diencephalon- gives rise to thalamus, hypothalamus and epithalamiums. Cerebrum- largest part of the brain.

9. Cerebrospinal Fluid (CSF) Clear fluid. Circulates through cavities in the brain (ventricles) and the spinal cord (central canal) and also in the subarachnoid space. Absorbs shock and protects the brain and the spinal cord. Helps transport nutrients and wastes from the blood and the nervous tissue.

10. CSF 150 ml in adult contains: glucose, proteins, lactic acid, urea, cations, anions, WBC Functions: 1.Reduces wt. of brain by 97% 2.Prevents head injury 3.Supplies brain with nutrition 4.Transports hormones along ventricular channels

12. Coverings of the Brain- Meninges skin skull dura mater arachnoid layer pia mater cerebral cortex

13. Blood Brain Barrier Protects brain from blood-borne toxins (e.g. urea, food toxins, bacteria) Endothelium of brain capillaries are loaded with tight junction to decrease permeability Not complete protection, some things still have to get through (e.g. fat-soluble molecules can pass through)

14. Brain Blood Flow and the Blood-Brain Barrier Brain receives approximately 20% of the total blood supply. Internal carotid and vertebral arteries carry blood to the brain. Internal jugular veins return blood from the brain.

15. The Brain The Cerebrum Frontal Lobe Parietal Lobe Temporal Lobe Occipital Lobe Cerebellum Brainstem

16. cerebrum corpus callosum thalamus cerebellum medulla oblongata hypothalamus pituitary pons spinal cord Pineal gland

17. Cerebrum Involved with higher brain functions. Processes sensory information. Initiates motor functions. Integrates information.

18. Motor, Sensory & Association Cortex

19. Motor vs. Sensory Nerves Sensory = Afferent – Send nervous impulse from sensory receptors to brain to bring in information – e.g. pressure, temperature, pain Motor = Efferent – Send nervous impulses from brain to body to accomplish an action – e.g. movement of a muscle, activation of a gland

20. Right-Left Specialization of the Cerebrum left side –language development –mathematical & learning capabilities –sequential thought processes right side –visual spatial skills –musical and artistic activities –intuitive abilities

21. Hemispheric Lateralization

22. Diencephalon thalamus hypothalamus pituitary

23. Thalamus Relay center for sensory tracts from the spinal cord to the cerebrum. Contains centers for sensation of pain, temperature, and touch. Involved with emotions and alerting or arousal mechanisms.

24. Functions of the Hypothalamus Control of the ANS. Production of hormones Regulation of emotional and behavioral patterns, eating and drinking, body temperature, and circadian rhythms.

25. Hypothalamus autonomic control center- blood pressure, rate and force of heart contraction, center for emotional response and behaviorautonomic control center- blood pressure, rate and force of heart contraction, center for emotional response and behavior body temperaturebody temperature water balance and thirstwater balance and thirst sleep/wake cyclessleep/wake cycles appetiteappetite sexual arousalsexual arousal control of endocrine functioning:control of endocrine functioning: Acts on the pituitary gland through the release of neurosecretions. Regulates:

26. Midbrain Contains ascending and descending tracts to the cerebrum and thalamus. Reflex center for eye muscles. Also involved with processing visual and auditory information (connects head movements with visual and auditory stimuli).

27. Pons Connects the two halves of the cerebellum. Regulates breathing.

28. Medulla Oblongata Composed of nerve tracts to and from the brain (these tracts cross over left to right and right to left) May be regarded as an extension of the spinal cord Almost all of the cranial nerves arise from this region

29. Centers of the Medulla Oblongata Vital centers: Cardiovascular center- Respiratory center- Also includes centers for vomiting, swallowing, sneezing, coughing and hiccupping. Houses five pairs of cranial nerves, VIII-XII. Portion of the ventricle found here is the fourth ventricle.

30. Medulla Oblongata Contains control centers for many subconscious activities Respiratory rate Respiratory rate Heart rate Heart rate Arteriole constriction Arteriole constriction Swallowing Swallowing Hiccupping Hiccupping Coughing Coughing Sneezing Sneezing

31. Cerebellum Controls and coordinates muscular activity. Important in equilibrium, posture and movement.

32. On Old Olympus Towering Tops A Fat Voracious German Viewed A Hop 1.Olfactory- smell 2.Optic- vision 3.Oculomotor- 4 of the 6 extrinsic eye muscles 4.Trochlear- extrinsic eye muscles 5.Trigeminal- sensory fibers to the face and motor fibers to the chewing muscles 6.Abducens- controls eye muscles that turn the eye laterally 7.Facial- facial expression 8.Vestibulocochlear- hearing and balance 9.Glosopharyngeal- tongue and pharynx 10.Vagus- from medulla- acetylcholine slows heart & breathing 11.Accessory- accessory part of vagus nerve 12.Hypoglossal- moves muscles under tongue

33. Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal Facial

34. Olfactory bulb Olfactory tract Olfactory receptor cell Filaments of olfactory nerve

37. Traumatic Brain Injuries Concussion: bump to the head Contusion: bruise Subdural or subarachnoid hemorrhage (SAH): Internal Bleeding Coup-contrecoup injury : head injuries and most often cerebral contusions head injuriescerebral contusions

38. Cerebrovascular Accidents (CVAs) Ischemia: a restriction in blood supply to tissuestissues Thrombus: a blood clot Embolism: This can cause a blockage in a blood vesselblood vessel Arteriosclerosis: thickening, hardening and loss of elasticity of the walls of arteriesarteries Stroke: brain attack, is when poor blood flow to the brain results in cell deathblood flow braincell

39. Degenerative brain diseases Alzheimer’s Down’s Parkinson’s Huntington’s Chorea MS Epilepsy Schizophrenia

40. Alzheimer’s Disease Alzheimer’s Disease is a disabling neurological disorder that afflicts about 11% of the population over 65, Its causes are unknown, its effects are irreversible and devastating and it has no cure at the present time. It involves widespread intellectual impairment, personality changes, sometimes delirium and culminates in dementia which is the loss of reason and ability to care for oneself. The patient with Alzheimer’s usually dies of some complication that affects bedridden patients such as pneumonia.

41. Alzheimer’s Disease Brains of patients with Alzheimer’s Disease show three distinct structural abnormalities: Great loss of neurons in specific regions such as the hippocampus and cerebral cortex. Plaques of abnormal proteins deposited outside neurons which are called amyloid plaques. Tangled protein filaments within neurons which are termed neurofibrillary tangles.

43. Dyslexia Dyslexia is an impairment of the brain’s ability to translate images received from the eyes into understandable language. Positron emission tomography or PET scans may provide some information about dyslexia.

44. PET Scans F-Dopa deficiency

45. Multiple Sclerosis or (MS) MS is the progressive destruction of myelin sheaths of the neurons in the CNS. Impulse transmission is disrupted often temporarily and repeatedly although a minority of individuals become totally disabled. The cause of MS is unknown and there is NO satisfactory treatment. Some scientists suggest that MS is an autoimmune disease that is triggered by a viral infection and so immunosuppressive drugs are often used.

46. Parkinson’s Disease Parkinson’s Disease or PD is a progressive disorder of the CNS that usually (although not always) affects victims around age 60. The cause is unknown but toxic environmental factors are suspected Pathological changes occur in the substantia nigra and basal ganglia and the degeneration of dopamine-producing neurons brings about a shortage of dopamine, a neurotransmitter. The imbalance between coexisting levels of dopamine and acetylcholine is thought to bring about most of the symptoms.

47. Parkinson’s Disease Symptoms of PD include unnecessary skeletal muscle contractions which often interfere with voluntary movement. Tremor, rigidity, and bradykinesia (slowed movement) are examples of other manifestations of this disorder. Drug therapy is directed toward increasing levels of DA and decreasing levels of Acetylcholine. Transplants of DA-rich fetal nerve tissue are an experimental treatment currently being explored.