1. Portland Community College
Lab Activity 14
The Brain
Portland Community College
BI 232

2. Brain Regions Cerebrum
Diencephalon (thalamus, hypothalamus, pineal gland)
Cerebellum
Brainstem (midbrain, pons, medulla oblongata)

3. Cerebrum Frontal lobe Motor, speech (usually left lobe), personality
Parietal lobe
Sensation (except smell), language
Occipital lobe
Vision
Temporal lobe
Hearing, smell, language

5. Cerebral Cortex
The superficial layer/rim of gray matter in the cerebral hemispheres
Gray matter consists of cell bodies, dendrites, and unmyelinated axons.

6. Sulci & Gyri Sulci Sulci: Shallow depressions of the cerebral cortex
Central sulcus is between the frontal and parietal lobes
Lateral sulcus is between the parietal lobes and temporal lobes.
Fissures: Deep grooves
Longitudinal: separates cerebral hemispheres
Transverse: separates cerebrum form the cerebellum
Gyri: The elevated ridges of the cerebral cortex
Serve to increase the surface area

7. Longitudinal Fissure
Transverse
fissure
Transverse Fissure

8. Central Sulcus
Lateral Sulcus

9. Precentral Gyrus: (frontal lobe) contains the primary motor area
Central Sulcus
Postcentral Gyrus: (parietal lobe) contains the primary somatosensory area.

10. White Matter & Basal Nuclei
White matter consists primarily of myelinated axons
Is beneath the gray matter cortex
Notice how it is the opposite arrangement from the spinal cord (Spinal cord: white matter is on the outside and gray matter is on the inside.)
Corpus callosum: Connects the right and left hemispheres
Basal nuclei: Islands of gray matter within the white matter.
Function: Involved in the subconscious control of skeletal muscle tone and the coordination of learned movement patterns

11. White Matter & Basal Nuclei
Corpus Callosum

12. Diencephalon
Structures
Thalamus
Hypothalamus
Epithalamus

13. Diencephalon: Epithalamus
Superior to the third ventricle, contains the pineal gland
Pineal gland

14. Diencephalon: Thalamus
Relay station for sensory input

15. Diencephalon: Hypothalamus
Pituitary gland: Attaches to the hypothalamus via the infundibulum
Mamillary bodies: Process olfactory sensations.
Mamillary body
Pituitary gland (not in this picture) would be hanging here

16. Diencephalon: Hypothalamus
Major Functions:
Controls somatic motor activities at the subconscious level
Controls autonomic function
Coordinates activities of the nervous and endocrine systems
Secretes hormones
Produces emotions and behavioral drives
Coordinates voluntary and autonomic functions
Regulates body temperature
Coordinates circadian cycles of activity

17. Cerebellum Functions: Coordination of movements
Adjustment of postural muscles
Vermis
Arbor Vita (white matter that looks like a leaf)

18. Brainstem 3 Structures: Midbrain (mesencephalon) Pons
Medulla oblongata
    
Corpora quadrigemina

19. Midbrain
Pons
Corpora quadrigemina
Medulla

22. Brainstem: Pons Functions:
Sensory and motor nuclei of Cranial nerves V, VI, VII, and VIII
Respiratory control:
Apneustic center and pneumotaxic center to modify the activity of the respiratory rhythmicity center in the medulla
Nuclei and tracts that process and relay information to and from the cerebellum

23. Brainstem: Midbrain Functions: Connects pons to cerebellum
Superior colliculi: visual reflex centers
Inferior colliculi: auditory reflex centers

24. Brain Meninges: Dura Mater
Continuous with the spinal meninges
Dura mater: An outer and inner fibrous connective tissue
Outer later is fused to the periosteum of the cranial bones (no epidural space)
Between the layers are tissue fluids, blood vessels and venous sinuses.
Venous sinuses are large collecting veins.
Venous sinuses drain into the internal jugular veins

25. Dural Folds
The inner layer of dura mater that extends into the cranial cavity.
Provide additional stabilization and support for the brain
Contain the dural sinuses

26. Dural Folds
Falx cerebri projects between the cerebral hemispheres in the longitudinal fissure
Superior sagittal sinus & inferior sagittal sinus
Tentorium cerebelli separates the cerebellar hemisphere from the cerebrum
Transverse sinus
Falx cerebelli divides the cerebellar hemispheres

28. Brain Meninges: Arachnoid & Pia Mater
Arachnoid mater consists of the arachnoid membrane and fibers of the arachnoid trabeculae that attach to the pia mater
Pia mater: attached to the surface of the brain, anchored by processes of astrocytes
Contains branches of cerebral blood vessels that penetrate the surface of the brain.
CSF is between these two membranes in the subarachnoid space

29. Ventricles

30. Brainstem: Medulla Oblongata
Functions:
Center for the coordination of complex autonomic reflexes (heart rate, respiratory rhythm, blood pressure)
Control of visceral functions (vomiting, swallowing)
Decussation of pyramids: a crossover point for the major motor tracts

31. Cranial nerves 12 pairs of cranial nerves
Originate from the nervous tissue of the brain
Some are mixed nerves while some are only sensory.
We will learn more later

32. Sheep Brain Dissection
Follow instructions in book for the sheep brain dissection.
When finished discard brain in the container provided.
Wash utensils and put back so other classes can use the materials.
ID structures on the brain models for next week’s quiz.

33. The End
The End