Dent 1 Nervous system: Brain

2. B R A I N

4. MAJOR PARTS OF THE BRAIN

5. CEREBRUM
• Largest part of the brain
• two cerebral hemispheres
connected by a mass of white
matter (corpus callosum)
• hemispheres are separated
by the Longitudinal fissure

6. HEMISPHERES ARE SEPARATED
BY:
• surface layer of each
cerebral hemisphere
composed of gray matter
• folds (gyri) separated
by fissures (sulci)
• large sulci subdivide
the surface of each
hemisphere into lobe

7. INSULA
• ka Island of Reil
• ▪folded deep within the lateral
sulcus between the temporal lobe
and the frontal lobe
• ▪functions
– perception
• – motor control
– self-awareness
– cognitive functioning

8. PRECENTRAL GYRUS
• mmediately anterior to the
central sulcus
• motor area
• – control voluntary
movements on the
contralateral side of the body
(corticospinal tract)
• • decussation at the
cervicomedullary junction

9. MOTOR HOMUNCULUS
• body is represented in an inverted
position
• nerve cells controlling the the feet
located in the upper part
• those controlling the movements of
the face and hands in the lower part

10. Homunculus

11. POSTCENTRAL GYRUS
• immediately posterior to
central sulcus
• sensory area
• – pain, temperature, touch,
and pressure from the
contralateral side of the body

12. BROCA’S AREA
• above the lateral sulcus motor speech area
• – dominant in the left hemisphere in right- handed
persons
• – dominant in the right hemisphere in left- handed
persons

13. SUPERIOR TEMPORAL GYRUS
• immediately below the lateral sulcus
• auditory area
• – concerned with reception and interpretation of
sound

14. BROCA’S AREA
• above the lateral sulcus motor speech area
• – dominant in the left hemisphere in right- handed
persons
• – dominant in the right hemisphere in left- handed
persons

15. VISUAL AREA
• situated on the posterior pole in the region of the
calcarine sulcus
• ▪receiving area for visual impressions

16. DIENCEPHALON

17. FUNCTIONS OF THE DIENCEPHALON
• 5 Functions of the Limbic System
• Feeding
• Flight
Fight
• Feelings
• Fucking (SEX)

18. Largest part of diencephalon
Influences mood and registers unlocalized, uncomfortable
perception of pain.
Thalamus

19. Small area located superior-posterior to the thalamus
Emotional and visceral response to odors
Epithalamus

20. Most inferior part of the
diencephalon
Maintaining homeostasis
Control of body
temperature, hunger, and
thirst
Hypothalamus
Sexual pleasure, feeling of good after a meal, rage, and fear.
Infundibulum – funnel-shaped stalk
Major role in controlling hormones from the pituitary gland

21. Brainstem
Connects spinal cord to
the brain
Consist of:
Medulla oblongata
Pons
Midbrain
Functions vital functions:
Control of heart rate,
blood pressure and
breathing

22. Medulla
Oblongata
Most inferior part of the
brainstem
Contains ascending and
descending
Pyramids- descending tracts
Conscious control of skeletal
muscle
Functions as:
Regulation of heart rate, blood vessel diameter,
breathing, swallowing, vomiting, coughing, sneezing,
balance, and coordination.

23. Pons
Contains ascending and
descending tracts
Relay information
between cerebrum and
cerebellum.
Footbridge
Functions as:
Breathing, swallowing, balance, and control.
Chewing and salivation.

24. Midbrain
Smallest region of the brainstem
Colliculi – 4 mounds posterior to the
midbrain
2 inferior – major relay centers for
auditory nerve pathways
2 superior – Visual reflexes;
turning the head on a tap shoulder,
sudden noise, bright flash of light
Coordination of eye movements and in diameter of pupil and lens
shape.
Substancia nigra – basal nuclei
Regulation of general body movement

25. Midbrain
• narrow part of brain that
passes through tentorial
notch
• two lateral halves called
cerebral peduncles
• – anterior part is crus cerebri
• – posterior part is
tegmentum
• – pigmented band of gray
matter (substantia nigra)

26. Flow of CSF
• Choroid plexus
Lateral ventricles
Foramen of Monro
Third Ventricle
Aqueduct of Sylvius
Fourth Ventricle
Foramina of Luschka and Magendie
Subarachnoid space
Arachnoid granulations