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Unit 4: Nervous System
Lab 2: Human Brain Structures
Jessica Radke-Snead, RD, MS
Bio 241 Anatomy & Physiology
Review from Lab 1
• On your own, review:
– Cerebral meninges
– Organization of tissue in brain
– Skull and muscle review (designated in your lab
guides)
Lab 2 Objectives
• What you need to work on today:
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Primary and secondary embryonic structures
External and internal anatomy of spinal cord
Lobes
Grooves
Ridges
Surface and internal anatomy
Functional areas
Structures associated with CSF
Cranial Nerves—location, function if you have time
BEFORE Lab 3 next week
• By next lab, please have a working knowledge
of:
– Cranial nerves: number, name, location, type and
function
– Spinal nerves: nerves, plexus and arising nerves
– Nerve functions: nerves, motor and/or sensory
– Skull and muscle review (designated in your lab
guides)
Organization of tissue in the brain
• White matter includes:
– Myelin sheath
– Nerve fibers
– Neuroglia nuclei
• Gray matter includes:
– Motor neuron cell bodies
– Nerve fibers
– Neuroglia
Neurulation:
Development of the Neural Tube
• ~Day 18,
embryonic
ectoderm thickens
to form a neural
plate, which
eventually gives
rise to the CNS
• ~Day 20, neural
plate forms the
neural groove with
neural folds on
each side
Neurulation Continued
• ~Day 21, neural folds fuse to form the ___
– Closure begins in the __ of the embryon and
progresses toward ___.
• On which days to the cephalic and caudal
ends close?
• The lumen of the neural tube develops into
what?
• __ ___ cells, formed from some ectoderm
cells, become sensory neurons, sympathetic
neurons, Schwann cells, etc.
Primary Structures of the CNS
Week 4
Secondary Vesicles
• Prosencephalon divides into:
– ___ Cerebral hemispheres (lateral outgrowths),
cerebral cortex, basal ganglia, hippocampus, amygdala
– ___  Retinas (optic vesicles), thalamus, hypothalamus
• ___  Tectum and tegmentum
• Rhombencephalon divides into:
– ___  Pons and cerebellum
– ___  Medulla oblongata
Secondary Structures of the CNS
Week 5
Major landmarks of the brain
• 3 major portions:
– Cerebrum, which contains the cerebral hemispheres
• Marked by gyri and separated by sulci
• Separated by the longitudinal fissure
• Connected by corpus callosum
– Cerebellum
• Contains ~50% of the brain’s neurons
• Marked by gyri, sulci and fissures
– Brainstem
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Diencephalon*
Midbrain
Pons
Medulla oblongata
Cerebral Hemisphere Lobes, Grooves
and Ridges
Anatomy of the brain
• Cerebral peduncles
– Anchor the cerebrum to the brainstem
– Corticospinal tracts pass through the peduncles to the
medulla
• Tegmentum: main mass of the midbrain
– Collaborates in fine motor control
• Tectum
– Corpora quadrigemina
• Superior colliculi: visual attention (blinking, focusing, pupillary
dilation/constriction)
• Inferior colliculi: receive signals from the inner ear and relay them to
other parts of the brain, ie thalamus
Midbrain Surface Anatomy
Cerebral Hemisphere Surface
Anatomy: Inferior View
Cerebrum
Olfactory Bulb
Olfactory Tract
Olfactory Tract
Mammillary Body
Cerebral Peduncle
Pons
I Olfactory (fibers)
II Optic
III Oculomotor
IV Trochlear (not shown)
V Trigeminal (cut)
VI Abducens
VII Facial
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Accessory
Cerebellar Peduncle
XII Hypoglossal (cut)
Cerebellum
Medulla Oblongata
Anatomy of the brain
• Medulla oblongata
– Contains sensory nuclei that receive input from the taste
buds, pharynx and viscera of the thoracic and abdominal
cavities
– Some motor nuclei
• Cardiac center: regulates HR and force of beat
• Vasomotor center: adjusts BV diameter
• Respiratory centers: regulate the rate and depth of breathing
• Pons
– Contains nuclei that relay signals from the cerebrum to the
cerebellum
– Contains nuclei involved with sleep, hearing, equilibrium,
taste, eye movements, facial expressions, facial sensation,
respiration, swallowing, bladder control and posture
Anatomy of the brain
• Thalamus
– 2 thalami joined by a narrow intermediate mass
– Most sensory input and other info going to the
cerebrum passes through it  thalami filter it
– Key role in motor control: relays signals from the
cerebellum to the cerebrum and provides
feedback loops
– Role in memory and emotional functions (limbic
system)
Anatomy of the brain
• Hypothalamus
– Between optic chiasm and mammillary bodies, forms floor
of the 3rd ventricle
– Major control center of the ANS and endocrine system
• Hormone secretion
• Autonomic effects: HR, BP, GI secretion and motility, pupillary
diameter
– Role in homeostatic regulation of most organs of the body
• Thermoregulation: monitors blood temperature (shiver, sweat,
vasodilation, vasoconstriction)
• Food/water intake: hunger and satiety communication, osmolarity
of blood to signal thirst
– Sleep and circadian rhythms
– Memory
– Emotional behavior
Anatomy of the brain
• Mammillary bodies
– Relay signals from the limbic system to the thalamus
• Pituitary gland (Hypophysis)
– Attached to hypothalamus via infundibulum (sella
turcica)
– Secretes numerous hormones, most of which regulate
the activities of other glands
• Pineal gland
– Produces melatonin and serotonin
– Timing and onset of puberty
Anatomy of the brain
• Fornix
– Axons in the brain that carry signals from the
hippocampus to the hypothalamus
• Septum pellucidum
– Thin membrane separating the anterior horns of
the left and right lateral ventricles of the brain
• Corpus callosum
– Thick band of nerve fibers that divides the
cerebrum into left and right hemispheres
Internal Anatomy of the Brain
Fornix
Septum Pellucidum
Corpus Callosum
Int Mass of Thalamus
Corpora Quadrigemina
Arbor Vitae (white matter)
Folia (gray matter)
Internal Anatomy of the Brain
Midbrain Internal Anatomy
Cerebellum and Brain Stem
Functional areas of the brain
• Primary cortex
– Detects basic dimensions of sensory information
• Association cortex
– Area outside the primary cortex that detects more
complex dimensions of sensory information
Functional areas of the brain
• Primary somatosensory area
– Somesthetic fibers decussate on way to thalamus
– Right postcentral gyrus receives signals from left side,
and vice versa
• Somatosensory association area (parietal lobe)
– Awareness of positions in our limbs
– Location of touch or pain
– Shape, weight and texture (something held in hand)
• Primary visual area
– Basic formation of visuals
• Visual association area (occipital lobe)
– Spatial perception
– Recognition of familiar objects
Functional areas of the brain
• Primary motor area
– Neurons send signals to the brainstem and spinal cord
that ultimately result in muscle contractions
• Motor association area
– Plan our behavior
– Neurons compile a program for the degree and
sequence of muscle contractions and send to:
• Primary auditory area
– Processes sound
• Auditory association area ( temporal lobe)
– Remember the name of a piece of music
– Identify a person by their voice
Functional areas of the brain
Structures involved with CSF
• 3 purposes of CSF:
– Buoyancy: brain remains suspended in CSF
– Protection: typically prevents brain from striking the cranium
– Chemical stability: rinses metabolic wastes from the CNS and
regulates chemical environment
• High glycine: disrupts temp and BP control
• High pH: dizziness and fainting
• Meninges of the brain Dura mater includes a
periosteal and meningeal layer (continues to vertebral
canal)
• Dural sinuses: spaces that collect blood that has
circulated through the brain
– Superior sagittal sinus
– Transverse sinus
• Heart and lungs 
Arterial blood:
1. Lateral ventricle’s
choroid plexus  Lateral
Ventricle
a. Through interventricular
foramina
2. 3rd Ventricle’s choroid
plexus  3rd Ventricle
a. Through cerebral
aqueduct
3. 4th Ventricle’s choroid
plexus  4th Ventricle
a. Through lateral and
median aperatures
4. Arachnoid villi of dural
venous sinuses 
superior sagittal sinus
5. Venous blood  Return
blood to heart
Structures involved with CSF
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4: Arachnoid villi of dural
venous sinuses  Venous blood
Cranial Nerves (by #)
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34
6
12
11
5
7
8
9
10