The nervous system contains the central nervous system (CNS) and peripheral nervous system (PNS). The CNS includes the brain and spinal cord. The brain is made up of regions including the cerebrum, cerebellum, and brainstem. It weighs about 1600g in males and 1400g in females and contains around 1012 neurons. The cerebral cortex consists of lobes such as the frontal, parietal, temporal, and occipital lobes which are involved in motor control, sensory processing, memory, and vision respectively. The spinal cord carries signals between the brain and body and contains gray matter containing neurons and white matter made up of axons.

1. CNS ANATOMY AND PHYSIOLOGY

2. Nervous system includes
CNS
PNS

3. • CNS contains
brain and
spinal cord

4. Introduction
• The brain weighs about 1600g in males and
about 1400g in females
• Has about 1012 neurons, each of which may
receive as many as 200,000 synapses
• Although these numbers connote a high level
of complexity, the CNS is actually quite
orderly.
4

5. Brain Regions
1. Cerebrum
2. Basal ganglia
3. Diencephalon
a. Thalamus
b. Hypothalamus
4. Brainstem
a. Midbrain
b. Pons
c. Medulla ob.
5. Cerebellum
5
Cerebellum

8. Cerebrum
• Largest portion of brain (80% mass).
– Most developed in man
• Responsible for higher mental functions,
concerning perception of fine sensation, learning,
memory, speech, judgment and planning.
• Corpus callosum:
– Major tract of axons that functionally interconnects
right and left cerebral hemispheres.
8

9. Gray and White Matter
• Microscopically, the CNS contains 2 neural
elements:
– Neuron cell bodies (clusters are known as nuclei)
– Nerve fibers (axons) in bundles called tracts.
• Viewed macroscopically, CNS tissues can be
distinguished by color:
– Gray matter consists of somata, dendrites, and
unmyelinated axons.
– White matter consists primarily of myelinated axons.
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10. Cerebral Cortex
• 3 types of functional areas:
– Motor: Control voluntary motor functions
– Sensory: Allow for conscious recognition of stimuli
– Association: Integration

11. Cerebral cortex
• The largest, most conspicuous portion of the brain.
• 2 hemispheres connected by the corpus callosum.
• Each hemisphere contains 5 lobes; frontal, parietal,
temporal, occipital and limbic lobes
• Has an outer cortex of gray matter surrounding an
interior that is mostly white matter, except for a few
small portions.
• The surface is marked by ridges called gyri separated by
grooves called sulci.
• Each gyrus contains one or more functional areas
called Brodmann´s areas.
11

14. 14
Primary motor
cortex
Broca’s Area
Premotor cortex
Frontal Eye
Field
Occipital lobe
Parietal Lobe
Temporal lobe
Cerebral lobes
44
45
3
1
2
4
6
4s
46
8
9
10
11
12
47
22
21
20
41 42
17
18
19
40
Brodmann´s areas of the cerebral cortex
5 7

18. Frontal Lobe
• Motor function of the cerebral cortex is
located in the frontal lobe, in front of the
central sulcus.
• It is divided in to 3 functional areas
– The primary motor area (area-4)
– The premotor area (areas 6, 8, 44, & 45)
– The prefrontal motor association area (areas 9-12)
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19. Motor homunculus

20. Parietal Lobes

21. Parietal Lobes
• Functions
Processing of sensory information
Spatial awareness and perception(Proprioception -
Awareness of body/ body parts in space and in
relation to each other)
Understanding speech and written words
• Require the integration of sensory information of
different modalities (visual, somatosensory …etc).

22. Parietal Lobes
• The parietal lobe consists of the following five
principal parts:
– The postcentral gyrus,
– The superior parietal lobule,
– The inferior parietal lobule,
– The precuneus, and
– The posterior portion of the paracentral lobule.

23. Similar but not
identical to
motor
homunculus

24. Temporal Lobe

25. Temporal Lobe
• The temporal lobe is a tongue-shaped anterior
projection that originates as an evagination of
the developing cerebral hemisphere

26. Temporal Lobe
Temporal lobe Function
Superior temporal gyrus -Primary sensory cortex(auditory and
olfactory)
-Unimodal association area(auditory)
-Werincke’s area
Inferior and middle temporal gyrus -Visual discrimination (as part of
occipitotemporal network)
Hipocampus and hipocampal formation -Learning and retentive memory
-Part of limbic network
Amygdala -Emotion (e.g. fear, anger..etc)

27. Occipital Lobe

29. Occipital Lobe
• The cuneus forms the upper bank, and the lingual
gyrus the lower bank, of the calcarine cortex.
• The occipital lobe is the visual cortex (areas 17,
18, and 19).
– Area 17(striate cortex) is the primary visual receptive
cortex (visual cortex).
– Unimodal visual Association Area [Area 18 & 19]
• Primary function: Processing, integration,
interpretation of Vision and visual stimuli

30. Types of Cells in the Gray Matter
• Pyramidal cells:
– They are neurons with pyramidal in shape
– Found in layers II, III, V and VI.
– Their axons leave the cortex and terminated in one of
the structures.
• Stellate cells:
– They are cortical star-shaped interneurons
– Found mainly in layer IV
– They have short axons terminating within the cortex

31. Types of Fibers in the White Matter
• Beneath the cortical mantle of gray matter lies
the white matter, which consists of three
types of nerve axons as well as glial cells and
blood vessels
1. Commissural fibers
• Connect to areas in the opposite hemisphere
2. Association fibers
• Connect cortical areas within the same hemisphere
3. Projection fibers
• Connect the cortex with lower centers

33. Spinal Cord

34. Relevant Anatomy