Anatomy Lecture Notes Section 3: Nervous System
The Central Nervous System: The Brain and the Spinal Cord
The nervous system is anatomically and functionally divided into two parts, the Central Nervous System
(the brain and the spinal cord) and the Peripheral Nervous System (the ganglia, and 12 pairs of cranial
nerves, plus 31 of pairs of spinal nerves). The Peripheral Nervous System (PNS) can be further delineated
into the Somatic Nervous System (SNS) which integrates control over skeletal muscle, and the Autonomic
Nervous System (ANS) which for the most part automatically regulates vital internal organs and systems.
The Brain
In anatomy, we can divide the brain into six (6) parts in terms of information processing:
1. Cerebrum
2. Diencephalon
3. Midbrain
4. Cerebellum
5. Pons
6. Medulla oblongata
To the right is a mid-sagittal section of
the brain showing various regions and
the six major divisions (red circled
numbers) of the human brain from the
highest to lowest level of information
processing.
1. Cerebrum
The cerebrum is the largest most
developed area of the human brain (see
above) and is considered to be the
center of the highest functions. Its
major functions include: Awareness of
sensory perception; voluntary control of
movement (regulation of skeletal muscle movement); language; personality traits; sophisticated mental
activities such as thinking, memory, decision making, predictive ability, creativity and self-consciousness.
The cerebrum is composed of 5 lobes, below is some basic information about them:
The Frontal Lobe – Encased within the frontal bone is the largest and most complex of the 5 lobes,
concerned with higher intellectual functions and behavioral aspects of humans. The primary motor cortex
controls the movement of skeletal muscles of the body.
The Parietal Lobe – Protected by the parietal bones of the skull, this lobe is primarily concerned with the
interpretation and integration of body sensory inputs. The somatosensory cortex is associated with
reception and perception of touch, vibration, temperature, and general body senses. Also involved in
spatial orientation, movement coordination, reading, writing and mathematical computation.
, 2
The Temporal Lobe - Contains the auditory cortex for the perception of sound, and the olfactory cortex
for the sense of smell. Also houses the language cortex usually in left hemisphere and participates in
recognition and interpretation of language. The amygdala and hippocampus (limbic system) connect to
the temporal lobe and aid in memory formation related to emotions, the sense of smell and sound.
The Occipital Lobe - This lobe contains the primary visual cortex for visual information interpretation. The
eyes transmit images to the visual cortex, which then determines colors, identify objects, shapes, and
other aspects of visual perception. Visual information is sent to the parietal lobes and temporal lobes for
further processing. The occipital lobe is also for reading comprehension; depth perception; recognition of
object movement. The parietal and temporal lobes use visual info to perform tasks like as opening a door
and connecting visuals with retained memories.
The Insula Lobe – A key role is visceral perception or awareness of internal organs and various bodily
states. When the bladder is empty we are not consciously aware of it, but when it becomes full, we
become aware of it. The gustatory cortex is responsible for taste perception, located in the insula the
frontal lobes. The insular lobe also enables us to read our own emotions and be aware of them.
Vocabulary for Brain Anatomy
Sulcus (sulci) – grooves on surface of cerebrum.
Gyrus (gyri) – fold of brain tissue between sulci.
Fissure - deep groove, separating hemispheres.
There are three (3) kinds of cerebral functional area:
1) Sensory areas – for receiving incoming sensory information.
2) Association areas – for analysis and placing information into context.
3) Motor areas – for sending out a response from the cerebrum to lower levels.
Two significant gyri on Cerebrum:
On Frontal Lobe: Precentral gyrus (motor). This region is the Primary Motor Cortex.
On Parietal Lobe: Postcentral gyrus (sensory). This region is the Primary Somatosensory Cortex.
, 3
General Anatomy of Cerebrum - there are 2 Hemispheres - Left and Right.
The Left Hemisphere
Controls writing, movement of the right side of body. Usually dominant in language and tasks that involve
symbolic reasoning. Language, logic, analytical, sequential, verbal tasks (fragmentary information
processing).
The Right Hemisphere
Controls touch, movement of the left side of body. Typically superior at non-verbal, visual and spatial
tasks. Spatial perception, artistic and musical endeavors (holistic information processing).
The Central Nervous System: The Brain and the Spinal Cord
The nervous system is anatomically and functionally divided into two parts, the Central Nervous System
(the brain and the spinal cord) and the Peripheral Nervous System (the ganglia, and 12 pairs of cranial
nerves, plus 31 of pairs of spinal nerves). The Peripheral Nervous System (PNS) can be further delineated
into the Somatic Nervous System (SNS) which integrates control over skeletal muscle, and the Autonomic
Nervous System (ANS) which for the most part automatically regulates vital internal organs and systems.
The Brain
In anatomy, we can divide the brain into six (6) parts in terms of information processing:
1. Cerebrum
2. Diencephalon
3. Midbrain
4. Cerebellum
5. Pons
6. Medulla oblongata
To the right is a mid-sagittal section of
the brain showing various regions and
the six major divisions (red circled
numbers) of the human brain from the
highest to lowest level of information
processing.
1. Cerebrum
The cerebrum is the largest most
developed area of the human brain (see
above) and is considered to be the
center of the highest functions. Its
major functions include: Awareness of
sensory perception; voluntary control of
movement (regulation of skeletal muscle movement); language; personality traits; sophisticated mental
activities such as thinking, memory, decision making, predictive ability, creativity and self-consciousness.
The cerebrum is composed of 5 lobes, below is some basic information about them:
The Frontal Lobe – Encased within the frontal bone is the largest and most complex of the 5 lobes,
concerned with higher intellectual functions and behavioral aspects of humans. The primary motor cortex
controls the movement of skeletal muscles of the body.
The Parietal Lobe – Protected by the parietal bones of the skull, this lobe is primarily concerned with the
interpretation and integration of body sensory inputs. The somatosensory cortex is associated with
reception and perception of touch, vibration, temperature, and general body senses. Also involved in
spatial orientation, movement coordination, reading, writing and mathematical computation.
, 2
The Temporal Lobe - Contains the auditory cortex for the perception of sound, and the olfactory cortex
for the sense of smell. Also houses the language cortex usually in left hemisphere and participates in
recognition and interpretation of language. The amygdala and hippocampus (limbic system) connect to
the temporal lobe and aid in memory formation related to emotions, the sense of smell and sound.
The Occipital Lobe - This lobe contains the primary visual cortex for visual information interpretation. The
eyes transmit images to the visual cortex, which then determines colors, identify objects, shapes, and
other aspects of visual perception. Visual information is sent to the parietal lobes and temporal lobes for
further processing. The occipital lobe is also for reading comprehension; depth perception; recognition of
object movement. The parietal and temporal lobes use visual info to perform tasks like as opening a door
and connecting visuals with retained memories.
The Insula Lobe – A key role is visceral perception or awareness of internal organs and various bodily
states. When the bladder is empty we are not consciously aware of it, but when it becomes full, we
become aware of it. The gustatory cortex is responsible for taste perception, located in the insula the
frontal lobes. The insular lobe also enables us to read our own emotions and be aware of them.
Vocabulary for Brain Anatomy
Sulcus (sulci) – grooves on surface of cerebrum.
Gyrus (gyri) – fold of brain tissue between sulci.
Fissure - deep groove, separating hemispheres.
There are three (3) kinds of cerebral functional area:
1) Sensory areas – for receiving incoming sensory information.
2) Association areas – for analysis and placing information into context.
3) Motor areas – for sending out a response from the cerebrum to lower levels.
Two significant gyri on Cerebrum:
On Frontal Lobe: Precentral gyrus (motor). This region is the Primary Motor Cortex.
On Parietal Lobe: Postcentral gyrus (sensory). This region is the Primary Somatosensory Cortex.
, 3
General Anatomy of Cerebrum - there are 2 Hemispheres - Left and Right.
The Left Hemisphere
Controls writing, movement of the right side of body. Usually dominant in language and tasks that involve
symbolic reasoning. Language, logic, analytical, sequential, verbal tasks (fragmentary information
processing).
The Right Hemisphere
Controls touch, movement of the left side of body. Typically superior at non-verbal, visual and spatial
tasks. Spatial perception, artistic and musical endeavors (holistic information processing).
