2. The brain is arguably the most important organ in the human body. It controls and coordinates actions and
reactions, allows us to think and feel, and enables us to have memories and feelings – all the things that make us
human.
While the brain only weighs about 3 pounds, it is a highly complex organ made up of many parts. Years of scientific
study of the brain have made it possible for scientists to identify the various areas of the brain and determine their
specific functions. The following information gives a brief description of some of the major parts of the human
brain.
The cranium
The brain is protected by a bony covering called the cranium (which, along with the bones of the face, make up the
skull). Inside the cranium, the brain is surrounded by the meninges. The meninges is made up of 3 layers of tissue:
•Pia mater – the layer closest to the surface of the brain
•Arachnoid membrane – the middle layer of tissue
•Dura mater – the outer-most layer
The cerebrum – the front of the brain
The largest part of the brain located in the front is called the cerebrum. The cerebrum is responsible for:
•Movement
•Body temperature
•Touch
•Vision
•Hearing
•Judgment
•Reasoning
•Problem solving
•Emotions
•Learning
The cerebrum has 2 parts: the right cerebral hemisphere and the left cerebral hemisphere. They are connected at
the bottom and have a deep groove running between them. In general, the right cerebral hemisphere controls the
left side of the body, and the left cerebral hemisphere controls the right. The right side is involved with creativity
and artistic abilities. The left side is important for logic and rational thinking.
The hemispheres of the cerebrum are divided into lobes, or broad regions of the brain. Each lobe is responsible for
a variety of bodily functions:
•Frontal lobes are involved with personality, speech, and motor development
•Temporal lobes are responsible for memory, language and speech functions
•Parietal lobes are involved with sensation
•Occipital lobes are the primary vision centers
The surface of the cerebrum appears wrinkled and is made up of deep grooves (called sulci) and bumps or folds
(called gyri). The outer part of the cerebrum is called gray matter and contains nerve cells. The inner part is called
white matter and contains connections of nerves.
The brainstem – the middle of the brain
The brainstem is located in front of the cerebellum. The brainstem is like the hard-drive of a computer. It is the
main control panel for the body that passes messages back and forth between the brain and other parts of the
body. The cerebrum, the cerebellum, and the spinal cord are all connected to the brainstem. The brainstem has
three main parts, the midbrain, the pons, and the medulla oblongata.
The brainstem controls vital functions of the body, including:
•Breathing
•Consciousness
•Cardiac function
•Involuntary muscle movements
•Swallowing
•Movement of the eyes and mouth
•Relaying sensory messages (pain, heat, noise, etc.)
•Hunger
The cerebellum – the back of the brain
Behind the cerebrum at the back of the head is the cerebellum. In Latin, cerebellum means “little brain.” However,
the cerebellum contains more nerve cells than both hemispheres combined. The cerebellum is primarily a
movement control center, responsible for:
•Voluntary muscle movements
•Fine motor skills
•Maintaining balance, posture, and equilibrium
Unlike the cerebrum, the left cerebellum controls the left side of the body, and the right cerebellum controls the
right side of the body.

3. Abbr Name of Artery Distribution
Anterior Cerebral Supplies most medial portions of frontal lobes and
ACA
Artery superior medial parietal lobes
Anterior Connects the anterior cerebral arteries at their closest
AComA
Communicating Artery juncture
Ascends through base of skull to give rise to the
anterior and middle cerebral arteries, and connect
ICA Internal Carotid Artery
with posterior half of circle of Willis via posterior
communicating artery
Trifurcates into temporal, frontal, and parietal
MCA Middle Cerebral Artery branches that supply most of the parenchyma of these
lobes
Connects the anterior circle of Willis with the
Posterior
PComA posterior cerebral artery of vertebral-basilar
Communicating Artery
circulation posteriorly
Posterior Cerebral Supplies the occipital lobe and the inferior portion of
PCA
Artery temporal lobe. A branch supplies the choroid plexus.
Superior Cerebellar
SCA Supplies the dorsal cerebellum, pons, and midbrain
Artery
Formed by the junction of the two vertebral arteries,
BA Basilar Artery it terminates as a bifurcation into the posterior
cerebral arteries
Anterior Inferior Supplies the inferior cerebellum and portions of pons
AICA
Cerebellar Artery and medulla

4. The vertebrals emerge from the posterior base of
VA Vertebral Artery
skull and merge to form the basilar artery
Posterior Inferior Supplies the inferior-posterior cerebellum, choroid
PICA
Cerebellar Artery plexus in 4th ventricle, and portions of medulla
Descends along the anterior (ventral) aspect of the
ASA Anterior Spinal Artery
spinal cord