Sheep Brain Dissection

Today in class, we dissected a brain. We only made three cuts but we identified most of the important structures of the brain, by using pins.
 Anterior (White) and Posterior (Black)

Cerebrum (yellow), Cerebellum (green), and Brain Stem (Red)

First we observed the external structure of the brain, starting with the meninges, the a shiny membrane substance surrounding the brain. After removing the meninges, we identified the anterior and posterior sides of the brain. Then we identified the cerebrum, cerebellum, and brain stem.

Cerebrum	is divided into four lobes and is responsible for body orientation, processing sensory input, cognition, memory, voluntary motor action, visual reception and association, auditory reception and interpretation, and expression powers.
Cerebellum	is responsible for motor control and coordination.
Brain Stem	performs necessary functions, like heart rate and breathing

Cerebrum

is divided into four lobes and is responsible for body orientation, processing sensory input, cognition, memory, voluntary motor action, visual reception and association, auditory reception and interpretation, and expression powers.

Cerebellum

is responsible for motor control and coordination.

Brain Stem

performs necessary functions, like heart rate and breathing

Myelin is a mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibers, increasing the speed at which impulses are conducted. 


Then we cut the brain longitudinally (like a hot dog) so that we could observe the medial plane of the brain. From this view of the brain we could see the white and grey matter of the brain. 

 Thalamus (yellow), Midbrain (blue), Medulla Oblongata(Red), Pons (Green)




 Hypothalamus (Blue)


Corpus Callosum (Red)                                                                                          Optic Nerve (Green)

Thalamus	works to correlate several important processes, including consciousness, sleep, and sensory interpretation.
Optic Nerve	transfer visual information from the retina to the vision centers of the brain via electrical impulses. The optic nerve is made of ganglionic cells or nerve cells.
Medulla Oblongata	regulate breathing, heart and blood vessel function, digestion, sneezing, and swallowing. This part of the brain is a center for respiration and circulation.
Pons	a bridge between various parts of the nervous system, including the cerebellum and cerebrum
Midbrain	is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.
Corpus Callosum	Large bundle of neuron fibers (myelinated axons or white matter) connecting 2 hemispheres
Hypothalamus	Maintains homeostasis and links the nervous system to the endocrine system

Then we made a cross sectional cut of the cerebrum (like a hamburger).

White and Gray Matter

Thalamus

works to correlate several important processes, including consciousness, sleep, and sensory interpretation.

Optic Nerve

transfer visual information from the retina to the vision centers of the brain via electrical impulses. The optic nerve is made of ganglionic cells or nerve cells.

Medulla Oblongata

regulate breathing, heart and blood vessel function, digestion, sneezing, and swallowing. This part of the brain is a center for respiration and circulation.

Pons

a bridge between various parts of the nervous system, including the cerebellum and cerebrum

Midbrain

is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.

Corpus Callosum

Large bundle of neuron fibers (myelinated axons or white matter) connecting 2 hemispheres

Hypothalamus

Maintains homeostasis and links the nervous system to the endocrine system