Brain Dissection

4/28/16

Brain Dissection Analysis

Question 1: Exterior of brain (drawing and picture are mirrored- use the color pins for reference)

White- anterior; yellow- cerebrum; green- cerebellum;
 black- posterior; red- brain stem

Drawing of the exterior of the brain

Question 2: Function of these structures

cerebrum- responsible for integrating sensory and neural functions. Initiates and coordinates voluntary movement in the body.
cerebellum- coordinate and regulate muscle activity.
brain stem- regulates involuntary functions like heart beat, breathing, sleeping, etc.

Question 3: Function of myelin in a neuron?

Myelin functions as insulation that allows the signal to travel faster down the neuron.

Question 4: Cross section of brain (drawing/ image are rotated- use color pins for reference)

Silver- medulla oblongata, white- pons; blue- midbrain;
yellow- thalamus; black- hypothalamus; red- corpus callosum; green- optic nerve

Drawing of interior of the brain

Question 5: Functions of structures pinned in question 4

Thalamus- sensory and motor signal relay; controls functions like sleeping and sensory interpretation

Optic nerve- transfer visual information from retina to visual center in brain

Medulla Oblongata- responsible for monitoring the circulatory and respiratory system.

Pons- relays messages from cortex and cerebellum to the cerebrum

Midbrain- motor control; eye movement, hearing, vision, sleep/ wake, alertness, and temperature regulation.

Corpus callosum- integrate motor, sensory, and cognitive signals between the two hemispheres 

Hypothalamus- controls the endocrine system via pituitary gland.

Question 6: Gray and white matter

Gray and white matter of cerebrum

Drawing of gray and white matter

Relate and Review:  In this lab we dissected a sheep's brain in order to identify structures. We started by examining the exterior structures such as the cerebrum, cerebellum, and brain stem. Afterwards we cut the brain in half longitudinally to find the thalamus, hypothalamus, optic nerve, medulla oblongata, pons, midbrain, and corpus callosum. From there we cut off a chunk of the cerebrum to further examine white vs. gray matter. There was a very clear difference in the density of tissue and how it related to its function in the brain. For example, the corpus callosum was fibrous and dense as it connects the two hemispheres. The cerebrum had a nice contrast of gray and white matter (see drawing in question 6) due to the various functions that it must perform. The dissection related to what we've been learning in class about the function of the structures of the brain as well as the structures themselves.