1. Central Nervous System (CNS)
CNS consists of the brain and spinal cord
Four regions of the brain
Cerebral hemispheres (cerebrum)
Diencephalon
Brain stem (midbrain, pons, and medulla)
Cerebellum

2. Two Cerebral Hemispheres
Surface markings
Ridges (gyri), shallow grooves (sulci), and deep grooves (fissures)
Five lobes
Frontal
Parietal
Temporal
Occipital
Insula

3. Functional Areas of the Cerebral Cortex
Left hemisphere is usually dominant
connected with math and language skills, and logic
Right hemisphere is connected with insight, visual-spatial skills and creativity

4. Diencephalon Three paired structures Encloses the third ventricle
Thalamus
Hypothalamus
Epithalamus
Encloses the third ventricle

5. Cerebral hemisphere Septum pellucidum Corpus callosum Interthalamic
adhesion
(intermediate
mass of
thalamus)
Fornix
Choroid plexus
Thalamus
(encloses third
ventricle)
Interven-
tricular
foramen
Posterior commissure
Pineal gland
(part of epithalamus)
Anterior
commissure
Corpora
quadrigemina
Mid-
brain
Hypothalamus
Cerebral
aqueduct
Optic chiasma
Stop here day 1
Arbor vitae (of
cerebellum)
Pituitary gland
Fourth ventricle
Mammillary body
Choroid plexus
Pons
Cerebellum
Medulla oblongata
Spinal cord

6. Thalamus 80% of diencephalon Gateway to the cerebral cortex
Sorts, edits, and relays information
Mediates sensation, motor activities, cortical arousal, learning, and memory

7. Hypothalamus Forms the inferolateral walls of the third ventricle
Autonomic control center for many visceral functions (e.g., blood pressure, rate and force of heartbeat, digestive tract motility)
Center for emotional response
Involved in perception of pleasure, fear, rage and in biological rhythms and drives

8. Hypothalamus
Regulates body temperature, food intake, water balance, and thirst
Regulates sleep and the sleep cycle
Controls release of hormones by the anterior pituitary
Produces posterior pituitary hormones

9. Epithalamus Most dorsal portion of the diencephalon
Pineal gland secretes melatonin
Helps regulate sleep-wake cycles
Choroid Plexus
Produces cerebrospinal fluid

10. Brain Stem
Three regions
Midbrain
Pons
Medulla oblongata

11. Brain Stem
Similar structure to spinal cord but contains embedded nuclei
Controls automatic behaviors necessary for survival
Contains fiber tracts connecting higher and lower neural centers
Associated with 10 of the 12 pairs of cranial nerves

12. Superior cerebellar peduncle Pons Middle cerebellar peduncle
Crus cerebri of
cerebral peduncles
(midbrain)
Thalamus
View (b)
Infundibulum
Superior colliculus
Pituitary gland
Inferior colliculus
Trochlear nerve (IV)
Trigeminal nerve (V)
Superior cerebellar peduncle
Pons
Middle cerebellar peduncle
Facial nerve (VII)
Inferior cerebellar peduncle
Abducens nerve (VI)
Vestibulocochlear nerve (VIII)
Glossopharyngeal nerve (IX)
Olive
Hypoglossal nerve (XII)
Thalamus
Vagus nerve (X)
Diencephalon
Hypothalamus
Accessory nerve (XI)
Midbrain
Pons
Brainstem
Medulla
oblongata
(b) Left lateral view

13. Midbrain Located between the diencephalon and the pons
Reflex centers for eye and head movement
Cerebral aqueduct
Channel between third and fourth ventricles

14. Pons Forms part of the anterior wall of the fourth ventricle
The Pons is mainly a conducting area
Nuclei help regulate respiration
Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial)

15. Medulla Oblongata Joins spinal cord at foramen magnum
Forms part of the ventral wall of the fourth ventricle
Transmits all ascending and descending impulses
Nuclei in the medulla regulate respiratory rhythm, heart rate, blood pressure
Centers for coughing, sneezing, swallowing and vomiting are found here

16. The Cerebellum 11% of brain mass Dorsal to the pons and medulla
Subconsciously provides precise timing and appropriate patterns of skeletal muscle contraction

17. Cerebellum Two hemispheres connected by vermis
Each hemisphere has three lobes
Anterior, posterior, and flocculonodular
Coordinates skeletal muscle movement and maintains posture and balance

18. Functional Brain Systems
Two networks of neurons that work together and span wide areas of the brain
Limbic system
Reticular formation

19. Limbic System
Structures on the medial aspects of cerebral hemispheres and diencephalon
Includes parts of the diencephalon and some cerebral structures that encircle the brain stem
Produces emotions – anger, fear, conflict
Modifies behavior

20. Reticular Formation
Three broad columns of nuclei along the length of the brain stem
Has far-flung axonal connections with hypothalamus, thalamus, cerebral cortex, cerebellum, and spinal cord
Maintains an alert state in the cerebral cortex
RAS (reticular activating system)
Severe injury results in permanent unconsciousness (coma)

21. Protection of the Brain
Four modes of protection
Bone (skull)
Membranes (meninges)
Watery cushion (cerebrospinal fluid)
Blood-brain barrier

22. Meninges Cover and protect the CNS
Protect blood vessels and enclose venous sinuses
Contain cerebrospinal fluid (CSF)
Form partitions in the skull
Three layers
Dura mater
Arachnoid mater
Pia mater

23. Skin of scalp
Periosteum
Bone of skull
Periosteal
Dura
mater
Meningeal
Superior
sagittal sinus
Arachnoid mater
Pia mater
Subdural
space
Arachnoid villus
Blood vessel
Subarachnoid
space
Falx cerebri
(in longitudinal
fissure only)

24. Cerebrospinal Fluid (CSF)
Functions
Gives buoyancy to the CNS organs
Protects the CNS from blows and other trauma
Nourishes the brain and carries chemical signals

25. Central Nervous System (CNS)
Central cavity
Outer white matter
Spinal cord
Central cavity surrounded by a gray matter core
Mostly neuron cell bodies and unmyelinated fibers
External white matter composed of myelinated fiber tracts
Dense collections of myelinated fibers
Inner gray matter
Spinal cord

26. Spinal Cord Structure Spinal nerves Cervical and lumbar enlargements
31 pairs
Cervical and lumbar enlargements
The nerves serving the upper and lower limbs emerge here
Cauda equina
The collection of nerve roots at the inferior end of the vertebral canal

27. Spinal Cord Functions Two way communication between brain and body
1. Ascending Pathways
carry sensory impulses to the brain
2. Descending Pathways
carry motor impulses to muscles and glands

28. Spinal Cord Protection Bone, meninges, and CSF
Cushion of fat and a network of veins in the epidural space between the vertebrae and spinal dura mater
CSF in subarachnoid space

29. Cervical
spinal nerves
Cervical
enlargement
Dura and
arachnoid
mater
Thoracic
spinal nerves
Lumbar
enlargement
Conus
medullaris
Lumbar
spinal nerves
Cauda
equina
Filum
terminale
(a) The spinal cord and its nerve
roots, with the bony vertebral
arches removed. The dura mater
and arachnoid mater are cut
open and reflected laterally.
Sacral
spinal nerves

30. Epidural space
(contains fat)
Pia mater
Arachnoid
mater
Spinal
meninges
Subdural space
Dura mater
Subarachnoid
space
(contains CSF)
Bone of
vertebra
Dorsal root
ganglion
Body
of vertebra
(a) Cross section of spinal cord and vertebra

31. Dorsal median sulcus
Gray
commissure
Dorsal funiculus
Dorsal horn
White
columns
Ventral funiculus
Gray
matter
Ventral horn
Lateral funiculus
Lateral horn
Dorsal root
ganglion
Spinal nerve
Central canal
Dorsal root
(fans out into
dorsal rootlets)
Ventral median
fissure
Ventral root
(derived from several
ventral rootlets)
Pia mater
Arachnoid mater
Spinal dura mater
(b) The spinal cord and its meningeal coverings

32. Gray Matter
Dorsal horns—interneurons that receive somatic and visceral sensory input
Ventral horns—somatic motor neurons whose axons exit the cord via ventral roots
Lateral horns (only in thoracic and lumbar regions) –sympathetic neurons
Dorsal root (spinal) gangia—contain cell bodies of sensory neurons

33. White Matter
Consists mostly of ascending (sensory) and descending (motor) tracts
Each spinal tract is composed of axons with similar functions