1. Ch 3: Anatomy of the Nervous System
Jan 16, 2013
Ch 3: Anatomy of the Nervous System

2. Divisions of the Nervous System
CNS
Brain & spinal cord
PNS
Nerves outside CNS

3. PNS SNS ANS Interacts with the outside world; skeletal muscles
Afferent nerves
Incoming sensory info
Efferent nerves
Outgoing motor signals
ANS
Controls body’s internal environment
ventral
dorsal

4. ANS Regulates the internal body processes 2 kinds of efferent nerves:
Sympathetic nerves
Stimulate, organize & mobilize energy
“fight or flight”
Arousal
Parasympathetic nerves
Conserve energy; bring back to base levels
“rest & digest”
Relaxation

5. ANS Appendices 1 & 2 (pg )

6. Neuro Quirk!!

7. The 12 Cranial Nerves Appendix 3 (pg. 493)
While most of the PNS project from the spinal cord, 12 pairs come from the brain
aka Auditory

8. Functions of the 12 Cranial Nerves Appendix 4 (pg. 494)
Olfactory
Smell
Optic
Sight
Oculomotor
Eye movement & pupil constriction
Trochlear
Eye movement
Trigeminal
Facial sensations & chewing
Abducens
Facial
Taste, facial expression, tears, salivation
Vestibulocochlear/Auditory
Hearing & balance
Glossopharyngeal
Salivation & swallowing
Vagus
Abdominal & thoracic organs
Accessory
Neck, shoulders & head
Hypoglossal
Tongue movement

9. Functions of the 12 Cranial Nerves
for fxns

11. Nervous System Breakdown Fig 3.2

12. Nervous System Breakdown

13. Protecting the Brain
Under the hard skull, 3 meninges help protect the brain
Dura mater
A tough leathery membrane
Arachnoid membrane
Spider web-like membrane
Beneath it is the subarachnoid space that contains numerous blood vessels & CSF
Pia mater
Delicate membrane adhering directly to the brain’s surface

14. Protecting the Brain Cerebrospinal Fluid (CSF) Cushions the brain
Produced by the choroid plexus
One interconnected reservoir of CSF
Fills the subarachnoid space, central canal of the spinal cord & ventricles of the brain
Lateral ventricles (2)
3rd ventricle
Cerebral aqueduct
4th ventricle
Hydrocephalus: a condition where a buildup of CSF causes brain to expand

15. Protecting the Brain Blood-Brain Barrier (BBB)
Prevents most toxic substances in the blood from passing into the brain
Tightly packed cells of the blood vessel walls prevent proteins & large molecules from getting through

16. Neuroanatomical Directions
Described in relation to the spinal cord
3 axes
Anterior-posterior
Dorsal-ventral
Medial-lateral

17. Neuroanatomical Directions
Be careful! Humans are a little tricky.
Superior-inferior

18. Neuroanatomical Directions

19. Neuroanatomical Directions
Proximal-distal
Brain Slices:
Horizontal section
Frontal section
Sagittal section
Cross section

20. Spinal Cord Made of gray matter & white matter
Gray: cell bodies
White: myelinated axons
Spinal nerves (31 pairs) attach to the spinal cord
Their axons attach at the dorsal or ventral roots
Dorsal: sensory
Ventral: motor
Efferent or afferent??

21. Major Structures of the Brain
Brain Stem:
Medulla
Pons
Cerebellum
Cerebral aqueduct
Thalamus
Hypothalamus
Cerebral cortex

22. Brain Stem: Medulla Pons Cerebellum
Tracts carrying signals between brain & body
Pons
Cerebellum
“little brain”
Important in sensorimotor functions; precise movement control; coordination

23. Brain Stem (cont.) Cerebral aqueduct Thalamus Hypothalamus
Connects 3rd & 4th ventricles
Thalamus
2 lobes joined across the 3rd ventricle
Sensory relay nuclei
Receive signals from sense, process them & send them to the cortex
Then get feedback from the cortex
Hypothalamus
Regulates motivated behaviors (sleep, sex, eating)
Via hormone release from pituitary gland

24. Cerebral Cortex Cerebral hemispheres Gray & white matter
Gyri & sulci (in humans)
Fissures
Longitudinal, central, lateral
Corpus callosum
Connects the 2 hemis

25. Cerebral Cortex 4 lobes of the brain Frontal Parietal Occipital
PFC
Parietal
Occipital
Temporal