Brain Dissection

This dissection was all about the brain. It wasn't as much dissection as it was discovery and viewing the main parts. We had only a few cuts, but we were able to identify the cerebrum, cerebellum, brain stem, corupus collosum, medulla oblongata, pons, midbrain, thalamus, and hypothalamus. After figuring out the location of each of the structures we looked through our notes to discover the function. The following functions go as follows. Firstly, the cerebrum in the brain provides for higher brain functions such as thoughts or actions. The cerebellum coordinates and regulates muscular activity. The brain stem transports information to and from the brain.  The myelin is the coating on the outside of a neuron. The myelin's function is to increase the speed of nerve impulses. The optic nerve main purpose is to transfers visual information from the retina to the visual centers of the brain from electrical impulses. The corpus collosum is a large bundle of neuron fibers that connects the two hemispheres of the brain. The midbrain controls breathing. The medulla oblongata aids in digestion. The pons helps with circulation.  Finally, thalamus' main function is to sort data and the hypothalamus' main function is to maintain homeostasis.

   

     
  

 

 

Sheep Eye Dissection

In this lab we dissected the eye of a sheep which is very similar to the human. Firstly we look at outer portion of the eye which includes the cornea, sclera, extrinsic muscles, fatty tissue, and optic nerve. The cornea is the outermost lens of the eye. It is cloudy because it is non living. The main job of the cornea is to focus the entry of light into the eye.The sclera is the white portion of the eye, it the toughest part of the eye specifically made strong to help prevent against injury. The extrinsic muscles allow the eye to move is many directions, we have 6 which give us a larger range of motion. Fatty tissue is the yellowy stuff surrounding the eye, its main job is to cushion the eye. Finally the optic nerve (picture 2), located at the back of the eye the optic nerve transfers visual information from the eye to the brain. Next we made an incision in the sclera which separated the eye into two hemispheres. In the picture the left hemisphere consists of the vitreous humor a gelatinous substance that helps keep the shape of the eye. The right hemisphere (posterior cavity) consists of the retina and the choroid. The retina processes light information and converts it to an image. If you peel away the that tissue you reveal the black choroid. The choroid is black due to pigments, it absorbs light so it doesn't bounce around the eye. After this we removed the vitreous humor from the left hemisphere (anterior part) this then reveal the lens, ciliary body, and suspensory ligaments. The lens is convex shaped, connected to the vitreous humor, and held in place by suspensory ligaments (picture 6 shows lens when removed from cavity). The lens bends rays of light in eye. Picture 7 shows the empty anterior cavity of the eye. The ciliary body is the mushroom looking lines/folds in this cavity, they contract to help adjust the lens. The aqueous humor can be found here too, much like the vitreous it is gelatinous and helps hold eye shape. The iris and pupil are also visible. The pupil is the small opening and the iris is the colored part surrounding the pupil. The pupil controls the amount of light that can enter the eye while the iris dilates and constricts the pupil size, this controlling light flow. The eye was very complex, but also very interesting to learn about.

                                                                          

Brain Clay Model

This is our model of the brain constructed entirely of clay. We included an outside view and an inside view (the left hemisphere along the sagittal plane and the right cerebral hemisphere) Major parts are labeled.

What If Part of Your Brain Was Missing?

Today I read an article titled "the girl with a hole in her brain". She is one of 9 living people who have been diagnosed with a missing cerebellum. If someone was to be missing this vital part of the organ they could possibly be severely mentally impaired, have movement disorders, or even epilepsy.But this women was different. What doctors can only describe as "less than would be expected",this women has only mild balance and speech problems. She's gone a whole 24 without noticing this problem until recently when she reported having dizziness and nausea. This led to a CAT scan and the discovery of the "hole" in her brain. 

To discover more about the brains other parts I was assigned to research about the Transverse fissure. More specifically to see if we could live without it. The transverse fissure is long narrow opening or space that separates the cerebrum from the cerebellum. I couldn't find any information on if a person could or could not live without a cerebral transverse fissure. From what I can infer if the space was not their the cerebellum would just be more fused to the cerebrum.