Download Brain (Ch 11) keynotes 08--1st

CNS & PNS
Ch. 11
CNS = brain and spinal cord
The brain is the largest and most complex part of the nervous system. It is
composed of about 1011 neurons ( 100 billion )
Brain made up of -----> cerebrum, diencephalon, brain stem and
! ! ! ! ! ! cerebellum
The brain is protected by the bony skull and the spinal cord is protected by the
vertebral column.
Below these bony coverings of the CNS are membranes between the bone
and the soft tissue to protect the CNS. These membranes are called
meninges.
Meninges have 3 layers : dura mater, arachnoid mater and the pia mater
( see fig 11.1 / 11.2 ) The dura mater is the outermost layer. Between the
arachnoid and the pia mater is a space which contains cerebrospinal fluid
(CSF). CSF helps protect and nourish the CNS by maintaining a stable
internal environment and absorbing forces to the brain or spinal cord. Itʼs this
fluid that bacteria and/or viruses invade causing spinal meningitis, which is
an inflammation of the meninges.
A ”spinal tap” (Fig. 11A / 11B) is a method used to remove CSF and check for
abnormalities in the fluid that may indicate an injury to the CNS.
The brain is divided into 5 major divisions, each consisting of a variety of parts. The
following Table lists these 5 divisions and some of the part associated with each.
Brain Divisions
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External Brain
Brain Region
Location
Frontal lobe
Area associated with the frontal
bone of the skull
Occipital lobe
Area associated with the occipital
bone of the skull
Parietal lobe
Area of the brain associated with the
parietal bone. Its between the
frontal and occipital lobes
Temporal lobe
Area associated with the temporal
bone of the skull
Limbic lobe
Only lobe of the brain which is
located on the inside of the brain
External Brain
Brain Region
Location
Longitudinal fissure
Deep groove that goes the length of
the brain. Separates the left & right
hemisphere
Lateral sulcus fissure
Deep groove that divides the
temporal lobe with the rest of the
body. On lateral side of brain
Sulcus
Little grooves of the brain (sulci)
Gyrus ( Convolutions )
Little ridges found on the brain (gyri)
Cerebellum
Located mainly inferior to the
occipital lobe of the brain
Pons
First big bulge of the brainstem
Medulla oblongata
A smaller bulge, inferior to the pons
Sagittal View of Brain
Brain Structure
Brief Description
Cerebrum
Major part of the brain. It consists of
folds (gyri) and valleys (sulci)
Corpus callosum
Curved, elongated white matter
connecting the 2 hemispheres
together
Lateral ventricle
This is a cavity filled with fluid. It is
located near the corpus callosum
Choroid plexus
A group of cells that are located
near the corpus callosum. They
produce cerebrospinal fluid
Pituitary gland
Small gland located inferior and
connected to the hypothalamus
Sagittal View of Brain
Brain Structure
Brief Description
Limbic lobe
Lobe which is an elongated gyrus
located immediately superior to the
corpus callosum
Thalamus
General area located inferior to the
corpus callosum
Hypothalamus
General area located inferior and
anterior to the thalamus
Midbrain
Located between the pons and
thalamus
Various Brain Structures & their Functions
Frontal lobe
Controls many of the fine motor
movements (muscle movement)
Important in higher level thinking
Occipital lobe
Involved in the interpretation of
vision
Parietal lobe
Involved in the interpretation of all
senses except hearing, smelling and
vision (Important in touch, pressure,
temperature and pain involving the skin)
Temporal lobe
Involved in the interpretating odors
and hearing
(Also help remember visual scenes & music)
Limbic lobe
Involved in long-term memory,
emotional experiences and feelings
Various Brain Structures & their Functions
Cerebrum
Important in higher level thinking
Corpus callosum
Group of nerves connecting the 2
hemispheres of brain together. It also
provides communication between the
2 hemispheres.
Instructions from the cerebrum tells
the body to start walking. This info is
sent to the cerebellum to carry out
this task. The cerebellum coordinates
skeletal muscle movement.
Cerebellum
Medulla oblongata
Pons
Controls the rhythmic pattern of the
heart and breathing. Also important
in causing one to sneeze/cough in
order to expel irritants thereby
protecting the lungs.
Alters the rhythmic pattern of heart
rate & breathing.
Midbrain
Controls muscle tone, also keeps us
“alert”
Thalamus
Acts as a relay station, by taking
external info and sending it to various
parts of the cerebrum for storage.
Consists of nerves that are involved
in detection of thirst. Also involved w/
various behavior characteristics.
Hypothalamus