Central Nervous System

1. Central Nervous System The brain and spinal cord.

2. History of Brain Knowledge The brain is a very complicated organ Much of our knowledge came from people who suffered accidents We have different methods to look at brain activity now.

3. Meninges Protect the brain and spinal cord Three layers Dura matter Arachnoid matter Pia matter

4. Dura Matter Tough coating, forms the internal periosteum of the skull Divides the brain into segments Falx cerebri - divides the cerebral hemispheres, attaches to the crista galli of the ethmoid bone Tentorium cerebelli - between the cerebellum and posterior portion of the cerebrum Epidural space around the spinal cord

5. Arachnoid Matter Thin weblike layer Located between the dura and pia matter Beneath the arachnoid is the subarachnoid space Filled with cerebrospinal fluid

6. Pia Matter Thin membrane Adheres closely to the surface of the brain and spinal cord Contains nerves and many small blood vessels

7. Brain Ventricles Interconnected spaces filled with cerebrospinal fluid Continuous with the central canal of the spinal cord 500ml of fluid is produced each day but there is only 140ml in the system at any one time Fluid is recycled through the bloodstream

8. Spinal Cord Continuous with the brain Begins at foramen magnum and ends near the first and second lumbar vertebrae Has 31 segments, each giving rise to a pair of spinal nerves Cervical enlargement sends nerves to the upper limbs Lumbar enlargement sends nerves to the lower limbs

9. Spinal Cord Anatomy Divided into right and left halves by the deep anterior median fissure and the shallower posterior median sulcus Gray matter within the white matter The central canal contains cerebrospinal fluid

10. Spinal Cord Anatomy Gray matter is H shaped Divided into three parts Anterior horns Efferent (motor) fibers Posterior horns Afferent (sensory) fibers Gray commisure The cross bar of the H

11. Functions of the Spinal Cord Control spinal reflexes Carry information to the brain (ascending tracts) Carry information away from the brain ( descending tracts)

12. Reflexes Nerve impulses follow certain pathways Reflexes are automatic, subconscious responses Control many activities like heart rate, breathing rate, blood pressure, sneezing, vomiting, knee jerk reflex etc.

13. The Brain

14. Brain Development Brain begins development very early Defects can occur before you know your are pregnant Folic acid seems to be important in preventing neural tube defects so vitamins should be taken before you try to get pregnant

15. Brain Facts 100 billion neurons Weighs about 3 pounds 1014 synapses 2% of body requires 20% of the blood supply Brain damage results if no oxygen for 3-5 minutes 45,000 neurons/min during gestation

16. Cerebrum Divided into two hemispheres Connected by the corpus callosum Covered with convolutions (gyri), shallow grooves (sulci), and deep grooves (fissures) Hemispheres divided by the longitudinal fissure Cerebrum/cerebellum divided by transverse fissure

17. Lobes of the Brain Named for the bone they are under Frontal Personality, verbal communication, planning, judging consequences of behavior, complex problem solving Parietal Comprehension of written and spoken language, skin and muscle sensations

18. Lobes of the Brain Temporal Lobe Auditory input, understanding of speech Memory of auditory and visual experiences Occipital Visual reception and interpretation

19. Hemisphere Dominance Each hemisphere of the brain controls the opposite side of the body 90% of right handed people and 64% of left handers are left brain dominant 10% of righties and 20% of lefties are right hemisphere dominant 16% of lefties have equal hemispheres

20. Left Hemisphere Generally responsible for Language Speaking Reading Math Analysis Computing

21. Right Hemisphere Generally responsible for: Body orientation Facial recognition Identifying objects by shape Music Global thinking Creativity Emotional and intuitive thinking

22. Diencephalon Between the midbrain and cerebrum, includes: Thalamus Major relay center, interprets sensory input (except smell), general awareness of pain, touch, and temperature

23. Diencephalon Hypothalamus Relay station between cerebrum and autonomic nervous system Links nervous and hormonal control Maintains fluid balance Regulates body temperature Regulates fluid intake Sleep/wake cycle Heart rate and blood pressure

24. Diencephalon Pineal Gland Regulates biological clock Seasonal Affective Disorder Optic Tracts & Chiasma

25. Limbic System Structures in the diencephalon plus part of the frontal and temporal lobes form the limbic system Controls emotional responses Modifies the way you act with feelings of fear, anger, pleasure, and sorrow Designed to increase chances of survival

26. Brain Stem Includes: Midbrain Pons Medulla oblongata

27. Midbrain Reflex located here include: Pupillary constriction Sound location Righting reflex Substantia nigra Helps coordinate movements The part damaged in Parkinson’s disease

28. Pons Regulates breathing Conveys info about facial sensations Control of chewing movements, eye movements, taste

29. Medulla Oblongata Controls: Heart rate Blood pressure Respiratory rate, depth Reticular Formation Activates cerebral cortex Filters out input during sleep Damage can cause coma

30. Cerebellum 2 hemispheres partially divided by the falx cerebelli White matter forms the arbor vitae Functions Smooth movement Maintains muscle tone and posture Maintains balance along with inner ear Compares intention with actual function

31. Cranial Nerves 1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial Smell Vision Eye movement Eye movement Eye, chewing teeth Eye movement Taste, expression salivation

32. Cranial Nerves Vestibulocochlear Glossopharyngeal Accessory hypoglossal Hearing/ equilibrium Taste, tongue, swallowing Shoulder/head movement, pharynx, larynx Tongue, speaking, chewing, swallowing