The Five Senses and Beyond: The Encyclopedia of Perception - Jennifer L. Hellier 2017

Brain Anatomy

The anatomy of the brain is very complex because of its intricate structure and function in the body. The central nervous system (CNS) acts as a control system by receiving, interpreting, and directing sensory information from the body to the brain. In turn, the CNS reacts to the sensory information by initiating motor movements such as sniffing and talking.

Brain Divisions

There are three major divisions in the brain, all of which have prime responsibilities for the normal functions of the body. These divisions are called the forebrain, midbrain, and hindbrain.

The forebrain is responsible for receiving and processing sensory information as well as thinking, perceiving, producing, and understanding language. It also controls voluntary motor function. The forebrain contains structures such as the thalamus and hypothalamus, which are responsible for motor control and relaying sensory information. It also contains the cerebrum, which is the largest part of the brain where most of the processing of sensory information takes place.

The midbrain makes up part of the brainstem with the hindbrain. The midbrain is the portion of the brain that connects the hindbrain to the forebrain. This region is responsible for auditory and visual responses as well as voluntary motor function.

The hindbrain contains structures such as the pons and cerebellum. This region of the brain assists in maintaining balance and equilibrium, coordinating voluntary movement, and conducting sensory information.

Brain Building with Clay

The central nervous system (CNS) consists of the brain, brainstem, and spinal cord. The brain serves as the control center for the CNS, is responsible for coordinating responses to stimuli, and exerts control over the body. The divisions and functions of the brain are: cerebrum, higher-order functions; cerebellum, modulation of brain signals; and brainstem, regulating the cardiovascular and respiratory systems and connecting the brain to the spinal cord. The cerebrum is further divided into lobes. The frontal lobes are responsible for motor responses, reward, attention, and motivation. The temporal lobes retain visual memories, language, storage of memories, and emotions. The occipital lobes are the visual processing center, and the parietal lobes integrate sensory information and special awareness (particularly body position).

Materials:

Five colors of clay (red, green, yellow, blue, and white), waxed paper, tabletop, toothpick, and paper towels

Directions:

Place the waxed paper on the tabletop and roll a gumball-size piece of yellow clay into a worm approximately one-eighth of an inch thick. Take this worm and slowly fold it into a loose ball in your hand. This will represent the frontal lobe of the cerebrum. Set this aside and clean your hands with the paper towels. Clean them between each color.

Next, roll a gumball-size piece of green clay and roll it as done previously. This will represent the temporal lobe of the cerebrum. Fold this clay into a loosely shaped ball and set aside.

Take a gumball-size piece of blue clay and roll it into a worm approximately one-eighth of an inch thick. Fold this clay into a ball; this will represent the occipital lobe of the cerebrum.

Then take a gumball-size piece of red clay and roll it as done previously. Fold the clay into a ball; this represents the parietal lobe of the cerebrum.

Repeat the aforementioned steps to make the other half of the brain and arrange the balls of clay into a brain. The frontal lobes sit in front followed by the parietal lobes, under which the temporal lobes sit. In the back sit the occipital lobes.

Next, use a gumball-size piece of white clay and flatten one side. Using a toothpick, carve several horizontal lines across the rounded side of the ball. Add a short tail; this represents the cerebellum and brainstem. Place the cerebellum and brainstem under the occipital lobes so that the brainstem points down.

Riannon C. Atwater

Structures

The brain contains many identifiable structures. Each structure/region is responsible for different aspects of bodily function, either sensory, motor, or both. The major structures of the brain are listed here in alphabetical order.

Amygdala—an almond-shaped region just anterior to the hippocampus. Its main functions are emotional responses and memory. Damage to this region is associated with posttraumatic stress disorder (PTSD).

Basal ganglia—deep structures near the midline of the cerebrum. The basal ganglia are four distinct groups of neurons consisting of the striatum (caudate and putamen), globus pallidus, substantia nigra, and subthalamic nucleus. Together these structures are involved in cognition and voluntary movement. Generally, damage to this area is associated with both Parkinson’s and Huntington’s diseases.

Brainstem—a set of structures located below the cerebrum and ventral to the cerebellum. The brainstem connects the spinal cord to the cerebrum and cerebellum. It consists of the midbrain, pons, and medulla oblongata. The brainstem relays information between the peripheral nerves to the CNS as well as regulating heart rate and breathing.

Cerebellum—the “little brain” found posteriorly and below the cerebrum. It is a “quality control center” for voluntary movement coordination. It also maintains balance and equilibrium.

Cerebral cortex—the gray matter of the cerebrum. It is divided into four lobes named after the bone they lie beneath. The frontal lobe is involved with decision making, problem solving, and planning. The occipital lobe’s function is vision. The parietal lobe receives and processes sensory information and language. Lastly, the temporal lobe processes emotions, memories, and speech.

Corpus callosum—a thick band of fibers connecting the left and right cerebral hemispheres.

Hippocampus—located in the temporal lobe. It is hypothesized as being the region involved with learning and long-term storage and retrieval of memories.

Hypothalamus—a structure deep in the brain and below the thalamus. It directs a multitude of important functions such as metabolism, body temperature, and hunger.

Pituitary gland—an endocrine gland located below the optic chiasm. It regulates other endocrine glands and maintains homeostasis.

Thalamus—a structure deep in the center of the cerebrum that modulates all sensory and motor responses except for olfaction.

Damage to the Brain

Although the meninges and the skull protect the brain, it still can be injured by a lack of oxygen. A stroke occurs when a blood vessel in the brain is blocked or bursts. Without the constant blood flow and oxygen required for a healthy brain, the neurons in the region of the stroke start to die. Brain damage can occur within minutes of the insult. Thus it is imperative to recognize symptoms of stroke and to act quickly. Stroke symptoms include but are not limited to sudden numbness or tingling, sudden change in vision, inability to smile on demand, or trouble speaking (slurred speech). In general, managing high blood pressure, cholesterol levels, and diabetes may prevent the probability of a stroke. Thus, it is necessary to take medication exactly as a health care provider prescribes it. A stroke is an emergency and always needs immediate emergency care.

Renee Johnson

See also: Brainstem; Cerebral Cortex; Olfactory Bulb; Visual System

Further Reading

The brain from top to bottom. (2013). http://thebrain.mcgill.ca/index.php

Hines, Tonya. (2011). Anatomy of the brain. Mayfield Clinic for Brain & Spine. Retrieved from http://www.mayfieldclinic.com/PE-AnatBrain.htm

WebMD. (2009). Brain & nervous system health center. Retrieved from http://www.webmd.com/brain/picture-of-the-brain