BRAIN
Meninges
There are three layers around the brain and central nervous system that protect it. The outer part, the dura mater, is tough and made of connective tissue. The middle is the arachnoid, which is weblike, is above the subarachnoid space with blood vessels. The pia mater under that connects with the brain, which consists of four major regions.
Cerebrum
This is the largest part of the brain and consists of two hemispheres separated with fibers named the corpus callosum. The right hemisphere controls the left, and vice versa. The left side controls logic and speech, while the right controls spatial awareness and recognition. Both hemispheres each have 5 lobes: The frontal lobes in the forehead control personality and behaviors, the parietal lobe is involved with navigation and reasoning, the occipital lobe works with comprehension of images and words, the temporal lobe controls the auditory sense and contains the hippocampus (involved with long-term memory), and the insula is hidden in the lateral sulcus. Surrounding the entire cerebrum is the cortex, which is made of “grey matter” that controls one’s consciousness.
Cerebellum
Located under the occipital lobes, it is connected to the cerebrum with the vermis and contains nerve fibers called cerebellar peduncles to communicate with the cerebrum. There is also white tissue called arbor vitae that branches out. The function of the cerebellum is to aid in balance, position, and posture.
Brain Stem
This connects the spinal cord to the rest of the brain and consists of three parts. The top of the brain stem, the midbrain, is also called the mesencephalon. It aids in reflexes involving vision and hearing. Below that is the pons, which is in charge of rhythmic breathing, bladder control, and is thought to be the cause of dreaming. Below the pons is the medulla oblongata which controls blood pressure, heart rate, and breathing.
Diencephalon
This connects the midbrain to the cerebrum and includes the thalamus, hypothalamus, and epithalamus. The thalamus is made of gray matter for taking sensory data and sending it to the cortex of the cerebrum. The hypothalamus also controls sensory data but also manages emotions. Furthermore, it is crucial in the endocrine system by sending out signals to the pituitary gland to make hormones. The epithalamus is in charge of circadian rhythms and is similar to a clock