1. Organization of the Nervous System
Lesson 4

2. The Central Nervous System
CNS
Brain
Spinal cord ~

3. Peripheral Nervous System
Somatic Nervous System - SNS
Sensory Division
Motor Division
Autonomic Nervous System - ANS
Sympathetic Division
Parasympathetic Division
Homeostasis ~

4. Divisions of the Brain Different schemes 5 major subdivisions
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon ~

5. Divisions of the Brain Forebrain cortex sub-cortical areas Midbrain
tectum & tegmentum
Hindbrain
cerebellum & pons
medulla ~

6. Terminology Dorsal - toward the back Ventral - toward the stomach
Anterior & Posterior
Rostral & Caudal ~

7. In reference to the BRAIN
Dorsal
Ventral
Inferior
Superior
Anterior
Posterior
Rostral
Caudal

8. In reference to brainstem & spinal cord
Superior
Inferior
Rostral
Caudal
Ventral
Dorsal
Anterior
Posterior

9. Neural Axis

10. Terminology Medial - toward the midline
Lateral - away from the midline
Ipsilateral - same side
Contralateral - opposite side
Decussate - crossover ~

11. Medial:
toward the
midline
Lateral:
away from
midline

12. Ipsilateral
same side mid-line
Contralateral
opposite side of mid-line

13. This tract of fibers decussates.
It crosses the midline

14. Terminology
Afferent - toward
Efferent - away from ~
Afferent
Efferent

15. Planes Coronal or frontal cross-section - salami Sagittal - side view
hot-dog bun
Horizontal
top view ~

16. Coronal Section

17. Horizontal Section
View from top

18. Mid-sagittal Section
Side view

19. Forebrain Cortical areas Fiber systems Landmarks Fissures /Sulci Gyri
Lobes ~

20. Superior surface
Longitudinal Fissure
(sulcus)

21. Central sulcus
Lateral sulcus

22. Major Lobes

23. Major Lobes & Primary Function
Frontal
planning
motor control
emotion
Parietal
somatosensory
maps of body & space
Temporal
auditory
memory
Occipital
vision ~

24. The Meninges Tough connective tissue Dura mater - tough outer layer
Arachnoid membrane - soft middle layer
Pia mater - soft inner layer, next to brain ~

25. Subarachnoid space Gap between arachnoid membrane and pia mater
Filled with Cerebrospinal Fluid (CSF)
Brain floats in CSF ~

26. The Meninges Brain Dura mater Arachnoid membrane
Subarachnoid space CSF
Pia mater
Brain

27. Ventricular System *Continuous with subarachnoid space
4 interconnected ventricles
chambers
Cerebrospinal Fluid (CSF)
manufactured in choroid plexus
125 ml, t1/2 = 3 hrs
*Buoyancy: 1400 g  50 g
Hydrocephalus
blockage of CSF flow ~

28. Ventricular System L V L V 3rd 4th Lateral Ventricles Third Ventricle
Cerebral Aqueduct
Fourth Ventricle
4th
Central Canal