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Biology 211 Anatomy & Physiology I

Biology 211
Anatomy & Physiology I
Dr. Thompson
The Brain
Human Central Nervous System
Starts as a groove and then
a hollow tube in the embryo;
Remains hollow & fluid-filled
throughout life;
These spaces form the
ventricles of the brain and
the central canal of the
spinal cord.
Cranial end of this hollow tube enlarges & folds to form
brain and its various parts
Caudal end of this hollow tube does not enlarge or fold;
Develops into spinal cord
From lab, you should understand what adult structures form
from the myelencephalon, metenchephalon, mesencephalon,
diencephalon, and telencephalon
More terms you need to know for brain and spinal cord
Gray Matter: Nervous tissue of the CNS consisting of
neuron cell bodies, their supporting glia, and unmyelinated
axons & dendrites.
Cortex: A region of gray matter on the surface of the
brain (found only on the cerebrum and cerebellum)
Nucleus: A deeper region of gray mattter, surrounded
by white matter
White Matter: Nervous tissue of the CNS consisting of
myelinated axons & dendrites and their supporting glia
Coronal Section of Brain
Cross Section of Spinal Cord
The brain has seven major (and many minor) regions:
Medulla Oblongata
Let’s discuss each of these briefly.
Thalamus develops from diencephalon
Most nuclei are relay centers:
Receive sensory information
from spinal cord, other regions
of brain, eyes, ears, tongue,
nasal epithelium.
Relay that to sensory regions
of cerebral cortex
Some nuclei relay motor
information from cerebral cortex
to other regions of brain
Some nuclei regulate sleep/wakefulness
Hypothalamus develops from diencephalon
Some nuclei regulate body
temperature, blood pressure,
hunger, thirst, fatigue.
Some nuclei regulate endocrine
(hormone) functions by
controlling activity of pituitary
gland (to which it is
Midbrain develops from mesencephalon
Often still called that.
Some nuclei regulate eye
movement & visual reflexes.
Large tracts of white matter
(myelinated axons) pass
through, carrying motor
information from cerebral
motor cortex toward other
parts of brain and spinal cord.
Some nuclei modify that information to regulate motor functions.
Large tracts of white matter pass through, carrying sensory
information from spinal cord toward thalamus.
Pons develops from metencephalon
Some nuclei relay signals
between cerebrum and
Some nuclei help regulate sleep,
respiration, swallowing, taste,
hearing, bladder control,
equilibrium, eye movement,
facial expressions, facial
sensation, and posture.
Motor information from cerebral cortex (white matter) continues
toward medulla oblongata and spinal cord; sensory
information continues from the medulla oblongata and spinal
cord toward the thalamus and toward the cerebellum.
Cerebellum develops from metencephalon
Nuclei and cortex receive both
motor information (from
cerebral cortex and nuclei
of other parts of brain) and
sensory information spinal
cord and other parts of the
brain. Uses that information
to coordinate and fine-tune
movement, particularly timing
and precision.
White matter carries that information to and from nuclei and
Medulla Oblongata develops from myelencephalon
Some nuclei help regulate
respiration, heart rate, blood
pressure, blood distribution.
Other nuclei regulate vomiting,
coughing, sneezing,
White matter carries motor
information from other regions
of brain to spinal cord, and sensory information from spinal
cord to other regions of brain.
Arises from the telencephalon
Consists of right and left
hemispheres separated by each
other by the longitudinal fissure
Each hemisphere is hollow,
containing a lateral ventricle
which is lined by ependyma
and filled with cerebrospinal
Each hemisphere
Includes both white
matter and gray
matter: Cortex
Basal Nuclei
Coronal Section
Cerebral Cortex
Gray Matter
2 - 4 mm thick
Folded into ridges, or gyri (singular: gyrus) separated by
shallow grooves, or sulci (singular = sulcus)
Different parts of brain separated by deep fissures
Lobes of Cerebral Cortex
Cerebral Cortex
Each gyrus, sulcus, and fissure has a name
(more than 50 gyri & sulci)
Cerebral Cortex
Each gyrus, sulcus, and fissure has a name
You don't need to know all of them
You will need to know the following:
Longitudinal Fissure
Central Sulcus
Precentral Gyrus
Postcentral Gyrus
Lateral Fissure/Sulcus
Parietooccipital Sulcus
Cerebral Cortex
Different regions of the cortex have specific functions
Three types of functional areas:
Cerebral Cortex
Different regions of the cortex have specific functions
From your reading and lab exercises, you should know
the functions of the following areas and where they are
Primary motor area
Motor association area
Primary somatosensory area
Somatosensory area
Primary visual area
Visual association cortex
Primary auditory area
Auditory association area
Questions on these may be on lecture and/or lab exams
Cerebral Cortex
Different regions of the cortex have specific functions
Two regions of cortex important in language:
Broca's Area deals with
formation of speech
Wernicke's Area deals
with recognition and
interpretation of speech
Both located primarily on
just one hemisphere
(usually the left).
Similar regions on other hemisphere control emotional
content of speech.
Gray matter forms
both: Cortex
Basal Nuclei
Coronal Section
Basal or Deep or Cerebral Nuclei
Globus Pallidus
Not shown: Amygdala
From your reading and lab exercises, you should also
know the locations of the
- Lateral ventricles
- Interventricular
- Third ventricle
- Fourth ventricle
- Mesencephalic
- Median aperture
- Lateral apertures
Questions on these may be on lecture and/or lab exams
Brain is surrounded by three layers of connective tissue:
Epidural Space
Dura Mater
Subdural Space
Arachnoid Mater
Subarachnoid Space
Pia Mater
The brain is protected in three ways:
1) Skull
2) Meninges
Pia Mater
Arachnoid Mater
Dura Mater
3) Floats in cerebrospinal
fluid in subarachnoid
Cerebrospinal fluid produced
within ventricles by specialized
tissue called choroid plexus.
Flows toward fourth ventricle
Exits from fourth ventricle
through three openings
(apertures or foramina) into the
subarachnoid space.
Median Aperture
Two Lateral Apertures
Surrounds brain & spinal cord.
Reabsorbed into blood
through arachnoid villi on
surface of brain
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