Biology 161 Lab – Brain
and Ventricles
Scott.lehbauer@lethbridgecollege.ab.ca
Brain Structures
Hypothalamus – found below the
thalamus it caps the brain stem
and forms the walls of the 3rd
ventricle. It is the main visceral
control center and vital in overall
body homeostasis functions
including:
1.
2.
3.
4.
5.
6.
7.
Autonomic Control Center
Center for Emotional Response
Body Temperature Regulation
Regulation of food Intake
Regulation of water balance
Regulation of sleep-wake cycles
Control of Endocrine Function
Hypothalamus
Brain Structures
Pituitary Gland – sits
securely in the sella
turcica of the sphenoid
bone. It is shaped like a
pea at the end of a stalk.

It is a major endocrine organ
secreting at least 9 hormones
including growth hormone,
thyroid stimulating hormone,
follicle stimulating hormone
and oxytocin to name a few.
Pituitary Gland
Brain Structures
Corpus Callosum –
is the largest commissure
which by definition
connect the two
hemispheres of the brain.
It lies superior to the
lateral ventricles.

it allows the two hemispheres
to coordinated function
Corpus Callosum
Brain Structures
Pons – “bridge” is the
bulge in the brainstem
between the midbrain
and the medulla
oblongata.

Is chiefly composed of
conduction fibers which
complete the pathway between
the higher brain centers and
the spinal cord.
Pons
Brain Structures
Medulla Oblongata
–
the most inferior part of
the brain stem. It
blends into the spinal
cord at the base.

Plays a crucial role in the
autonomic reflex center.
Important visceral motor
nuclei include
1.
2.
3.
Cardiovascular center
Respiratory centers
Additional centers that control
Vomiting, hiccupping,
swallowing, coughing and
sneezing.
Medulla Oblongata
Brain Structures
Cerebellum – “Small
Brain” accounts for about
11% of total brain mass.
Located dorsal to the
medulla and pons.

Processes information from the
cerebral motor cortex and
visual and equilibrium
pathways, and “instructs”
motor centers which result in
proper balance, posture,
smooth coordinated skeletal
muscle movements.
Cerebellum
Brain Structures
Thalamus – “inner room” is a
deep well hidden brain
region. It contains a large
number of nuclei.

Each nuclei receives and
deciphers information from the
cerebral cortex and other areas
“relay station”. The thalamus
plays an integral in mediating
sensation, motor activities,
cortical arousal, learning and
memory.
Thalamus
Brain Structures
Midbrain – a
conduction pathway
between the higher
and lower brain
centers. Contains
the corpora
quadrigemina
Midbrain
Brain Structures
Corpora quadrigemina –
“quadruplets” which is 4
raised dome-like
protrusions on the dorsal
midbrain surface.
1.
2.
Visual reflex center –
coordinates head and eye
movements to follow moving
objects.
Auditory Reflex center –
reflexive response to sharp
sounds that cause you to turn
your head towards and
startling sound “startle reflex”
Corpora
Quadrigemina
Brain Structures
Cerebrum – gray
matter localizes and
interprets sensory
inputs.
1.
2.
3.
Controls voluntary and
skilled skeletal muscle
activity.
Functions in intellectual and
emotional processing
Important in initiation of
skeletal muscle movements
Cerebrum
Cerebral Lobes
Parietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
Cerebellum
Brain Structures - Ventricles



Are continuous spaces
which reside inside the
tissue of the brain
They are continuous
with the central canal
of the spinal cord.
They are full of
Cerebral Spinal Fluid
Brain Structures - CSF
CSF (Cerebral Spinal Fluid) – is found in
and around the brain and spinal cord.
 It forms and liquid cushion and gives
buoyancy around the CNS. The CSF
reduces the weight of the brain by 97% and
prevents the brain from crushing itself.
 It also protects the CNS from trauma and
helps nourish the brain.
Brain Structures - CSF
Choroid Plexus – these
structures hang from the roof
of the ventricles and produce
CSF.
Arachnoid Villi – knob
like projections which
Arachnoid
protrude through the dura Granulations
matter into the superior
sagittal sinus. CSF is
absorbed into the venous
blood of the sinus here.
Choroid
Plexus
Brain Structures - Ventricles
1st and 2nd Ventricles


“lateral ventricles” are deep
within either cerebral
hemisphere.
Are large C-shaped ventricles
Foramen of Munroe –

“interventricular foramen”
which attaches the lateral
ventricles to the narrow 3rd
ventricle
1st and 2nd Ventricles
Brain Structures - Ventricles
3rd Ventricle

Aqueduct of Sylvius
Thin medial ventricle
Aqueduct of Sylvius
 “cerebral aqueduct”

connects the 3rd and forth
ventricle
3rd Ventricle
Brain Structures - Ventricles
4th Ventricle –

lies in dorsal to the pons and
superior medulla. It is
continuous with the central
canal of the spinal cord.
4th Ventricle
Central Canal of Spinal
Cord  Continues down the
spinal cord from the
ventricles of the brain.
Central Canal
Hydrocephalus


“Water on the brain” is a condition
where the CSF cannot be drained or
reabsorbed.
CSF accumulates and exerts pressure
on the brain
Hydrocephalus

Hydrocephalus is
treated by inserting
a shunt into the
ventricles to drain
the excess fluid into
a vein in the neck.
Brain Structures - Meninges
Meninges – “membrane” are three
connective tissue membranes that lie just
outside the CNS (Brain and Spinal Cord).
Their functions include;
1.
Cover and protect the CNS
2.
Protect blood vessels and enclose the
venous sinuses
3.
Contain CSF
4.
Form partitions in the skull
Brain Structures - Meninges
Brain Structures - Meninges
Dura Mater –
 “tough mother” is the
strongest layer.
 Two layered sheet of
fibrous connective tissue.
Arachnoid  Forms a loose brain
covering.
 Separated from the dura
matter by a serous cavity
“Subdural space”
 The “subdural space” is
filled with fluid
Dura Matter
Superior Sagittal
Sinus
Arachnoid
Brain Structures - Meninges
Subarachnoid Space
 Web-like extensions span this
space and attach the arachnoid
to the pia matter.
 This space is filled with CSF
and large blood vessels
Pia Mater
 “gentle mother” is composed
of delicate connective tissue
and is full of tiny blood vessels.
 This is the only layer that
clings tightly to the brain
following every contour.
Spina Bifida
“forked spine” results from the incomplete
formation of the vertebral arches
3 Types
1.
Spina bifida occulta – not severe results in a small
tuft of hair on the back and has no neurological
ramifications.
2.
Spina bifida meningocele – more severe, a saclike cyst protrudes from the child’s spine. The
cyst contains CSF and Meninges.
3.
Spina bifida myelomeningocele – similar to above
only the cyst contains neural structures. The
more neurological structures the cyst contains the
more neurological impairment.

Spina Bifida


There is no treatment
for the neurological
defects caused by
spina bifida.
Doctors will perform
surgery to close the
vertebral column to
prevent further
damage and infection.
An infant with Spina Bifida