1. CH 13

2. Reminder: Consists of…. the brain and spinal cord

3. The outer covering of the brain consists of bone and the outer covering of the spinal cord consists of vertebrae bones. The inner coverings consist of THREE Layers called meninges.…we are going to talk about the three layers from outward in…

4. Dura Mater Outer most covering

5. Arachnoid membrane The second layer of meninges in between the dura mater and pia mater. Only meninge which contains Cerebro spinal fluid (CSF)

6. Pia mater Innermost meninge Adheres to outermost surface of the brain

7. Cerebrospinal fluid (CSF) Another form of protection for the CNS Acts as a liquid cushion 140 mL of cerebro spinal fluid in the average human adult

8. Made from blood plasma CSF can be found in… –Subarachnoid space –Central canal of the spinal cord –Ventricles within the brain

9. Lumbar Puncture Withdrawal of cerebrospinal fluid from subarachnoid space (under arachnid and outside pia matter) Physician inserts a needle just above fourth vertebrate Cerebrospinal fluid can be tested for presence of blood or bacteria

11. Structure Dorsal nerve root- brings sensory information to spinal cord Ventral Nerve root- brings motor information to the spinal cord FUNCTION Include colliculi which control visual and auditory centers of the brain

12. Hydrocephalus Interference with circulation of cerbrospinal fluid. Example: brain tumor might press against brain, now allowing cerbraspinal fluid to drain. For an infant, a tube can be inserted to drain fluid since infant skull has not ossified. In adult, this is more problematic since skull will not yield.

14. The brain is made up of … –Brainstem –Cerebellum –Cerebrum

15. Brainstem Consists of –Medulla oblongata- connects the brain to the spinal cord and is in control of vital and control centers within the brain. –Pons- charge of normal breathing rhythms –Midbrain- Include colliculi which control visual and auditory centers of the brain

16. Cerebellum coordinates skilled movements, helps control posture, and controls skeletal muscles for balance

17. Cerebrum 60% of brain weight Left and right halves Wenicke’s area- comprehension of written Broca’s area- motor speech and articulation of words Consciousness memory

18. Diseases of the CNS Alzheimers- Demntia- lesions develop in brain in middle to late adulthood. Cause unknown. Huntingtons- dominant gene that causes body to make a protein incorrectly which prevents normal function. Symptoms do not occur until late adulthood. Cerebral palsy- permanent, nonprogressive damange to motor control areas of brain at birth or shortly after Epilepsy- Chronic seizures caused by tumors or chemical imbalances MS- Myelin loss and destruction of oligodendrocytes (what are those again??) causing lack of coordination, visual impairment, and speech disturbance.

19. Chapter 14 Peripheral Nervous System Now we talk about all the spinal nerves, cranial nerves, and the many smaller nerves that branch from these main nerves!

20. Sensory (afferent) division –Sensory afferent fibers – carry impulses from skin, skeletal muscles, and joints to the brain –Visceral afferent fibers – transmit impulses from organs to the brain Motor (efferent) division –Transmits impulses from the CNS to effector organs What are the divisions of the peripheral nervous system?

21. Spinal Nerve Spinal nerves (31 pairs of them!) have no special names but are numbered according to level of vertebral column. Roots lay within spinal cavity. Ventral(Anterior)root(includes motor fibers) Dorsal(Posterior)root(includes sensory fibers)

22. Cranial Nerves There are 12 pairs of cranial nerves. The twelve pairs of nerves are assigned names and numbers. They can be of three types: -Sensory Cranial nerves- consist of sensory axons only. -Motor Cranial nerves- consist of motor axons only. -Mixed cranial nerves- Contain axons of sensory and motor neurons.

23. Nerve Types *you do not need this for test but this shows the 12 pairs and how they can be classified as a type of nerve* Olfactory: Sensory Olfactory: Sensory Optic: Sensory Optic: Sensory Oculomotor: Motor Oculomotor: Motor Trochlear: Motor Trochlear: Motor Trigeminal: Sensory and Motor Trigeminal: Sensory and Motor Abducens: Motor Abducens: Motor Facial: Sensory and Motor Facial: Sensory and Motor Vestibularcochlear: Sensory Vestibularcochlear: Sensory Glossopharyngeal: Sensory and Motor Glossopharyngeal: Sensory and Motor Vagus: Sensory and Motor Vagus: Sensory and Motor Accessory: Motor Accessory: Motor Hypoglossal: Motor Hypoglossal: Motor

24. Reflexes A reflex is a predictable, involuntary response to a stimulus. They produce the simplest behaviors. Ex. Removing hand from a hot object. Occur over neural pathways called reflex arcs. 5 basic components: receptor, sensory neuron, integration center, motor neuron, and effector

25. Somatic Reflexes- contractions of skeletal muscles Knee Jerk: extension of lower leg from tap on patellar tendon Knee Jerk: extension of lower leg from tap on patellar tendon Ankle Jerk: extension of foot from tap on Achilles tendon Ankle Jerk: extension of foot from tap on Achilles tendon Babinski: extension of great toe from stimulation of sole of foot in normal infants Babinski: extension of great toe from stimulation of sole of foot in normal infants Corneal: blinking from touching cornea Corneal: blinking from touching cornea Abdominal: drawing in abdominal wall from stroking side of abdomen Abdominal: drawing in abdominal wall from stroking side of abdomen

26. How a Reflex Works http://health.howstuffworks.com/adam- 200012.htm http://bcs.whfreeman.com/thelifewire/conte nt/chp46/46020.html

27. Autonomic Reflexes Autonomic (visceral) Reflex: contractions of smooth/cardiac muscles or gland secretions Autonomic (visceral) Reflex: contractions of smooth/cardiac muscles or gland secretions

28. Discussing this Flow Chart Again…