Task 1: The brain
PART 1: The nervous system___________________________________________________________
1. What are different functions of the lobes?
2. How is the nervous system organized?
3. How does an action potential work (+ and what are neurotransmitters?)
4. Describe the anatomy of the brain and its functions (subcortical parts)
5. Describe how neurons look like, how the work
6. How does the blood flow in the brain?
Kolb, B. & Whishaw, I.Q. (2015). Fundamentals of Human Neuropsychology (7th Edition) H3 & reader blok 4.
3.1: neuroanatomy: finding your way around the brain
Describing location in the brain:
Anterior/ frontal: in front or
towards to nose <-> posterior:
to the back or toward to tail
end
Dorsal/ superior: toward the
surface of the back or to the
top of the head <-> ventral/
inferior: toward the surface of
the chest or the bottom of the
head
Medial: at the centre or
inbetween <-> lateral: at the
side
Proximal (nearest/ close) and
distal (far)
Ipsilateral: structures on the
same side of the body;
contralateral: structures on
the opposite sides of the
body; unilateral: on one side
of the body; and bilateral:
both sides of the body.
Sections in the brain:
Coronal section: vertical plane, revealing a
frontal view.
Horizontal section: horizontal plane,
produces a dorsal view (looking from
above)
Sagittal section: lengthways, from front to
back. Reveals a medial view (from the side).
Movement:
Movement toward a brain structure
is afferent (sensory/input), whereas a
movement away from it is efferent
(motor).
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, 3.2: overview of nervous system structure and function
The nervous system consists of the central nervous
system (CNS; brain and spinal cord) and the
peripheral nervous system (PNS: everything else).
The PNS has 2 divisions:
Somatic nervous system (SNS): consists of 2
sets of inputs and outputs to the CNS: the
spinal and cranial nerves to and from the
sensory organs and to muscles, joints and
skin. The SNS transmits incoming sensory
information to the CNS ( vision, hearing,
pain, temperature, touch, position and
movement of body parts) and produces
movements in response.
Autonomic/ automatic nervous system
(ANS):controls the functioning of the body’s
internal organs through the parasympathetic
(calming) nerves or to "fight and flee"
through the sympathetic (arousing) nerves.
Above is from an anatomical standpoint. In
this book, the functional organization is used. This focuses on how the 3 parts of the system
interact.
The brain and the spinal cord are supported and protected
from injury and infection in 4 ways:
1. The brain is enclosed in the skull and the spinal cord
is encased in a series of interlocking bony vertebrae
(wervels). So the CNS lies within bony encasements,
while the SNS and ANS lie outside them. bone.
2. Within the bony case enclosing the CNS is a triple-
layered set of membranes: the meninges.
a. Outer layer: dura mater: tough double layer
of tissue enclosing the brain in a kind of loose sack.
b. Middle membrane: arachnoid membrane: very thin sheet (spider web).
c. Inner layer: pia mater: moderately though tissue that clings to the brain’s surface.
3. The cerebrospinal fluid (CSF) protects the brain and spinal cord from shock and sudden
pressure changes. The CSF circulated through the brain’s 4 ventricles, the spinal column and
with the subarachnoid space in the meninges (zie 2). CFS is continually being made and
drained off into the circulatory system (bloedsomloop) through connecting channels among
the ventricles.
a. If outflow in these channels is blocked hydrocephalus/ water brain / waterhoofd
4. The blood- brain barrier protects the brain and spinal cord by limiting the movement of
chemicals from the rest of the body into the CNS and by protecting it from toxic substances
and infection.
Blood supply
The brain receives blood from 2 internal carotid arteries (halsslagaders) and 2 vertebral arteries.
These 4 arteries connect at the base of the brain, where they enter the skull.
They branch off into several smaller arteries that irrigate the brainstem and cerebellum and give rise
to three cerebral arteries that irrigate the forebrain:
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, Anterior cerebral artery (ACA)
in medial and dorsal parts of the
cortex (centre en bovenkant)
Middle cerebral artery (MCA) in
lateral surface of the cortex
(zijkant)
Posterior cerebral artery (PCA)
ventral and posterior surfaces
(onderkant)
If a blood clot forms in a cerebral artery
and causes a stroke, symptoms will vary
according to the location of the loss of
blood supply.
Neurons and glia
The brain originates in a single, undifferentiated
neural stem cell (a germinal cell). Self-renewing
multipotential neural stem cells give rise to the
different types of neurons and glia in the nervous
system.
Stem cell: divides and produces 2 stem cells, both
of which can divide again (stem renewal). A stem
cell dies after each division progenitor cells act
as precursor cells (voorloper cellen) and give rise to
nondividing primitive blasts blasts: neuroblasts
differentiate into neurons and glioblasts
differentiate into glial cells. These 2 types of cells
take many forms and constitute the entire adult
brain. specialized
Different neurons:
Sensory neurons
o the simplest sensory receptor, a cell that transduces sensory
information into nervous system activity, is the bipolar neuron. It
consists of a cell body with a dendrite on one side and an axon on
the other. In the retina (netvlies) of the eye
o A somatosensory neuron projects from a sensory receptor in the
body into the spinal cord. Its dendrite and axon are connected,
which speeds information conduction because messages do not
have to pass through the cell body.
Interneurons – these link up sensory and motor- neuron activity in
the CNS. It has multiple dendrites with many branches and one axon.
Interneurons include stellate (star-shaped) cells characterized by
many branches in the thalamus, pyramidal cells in the cortex that
have a pyramid-shaped cell body, and Purkinje cells of the
cerebellum. In brain and spinal cord.
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, Motor neurons – motor neurons project to facial and body muscles. All
behaviour (movement) produced by the brain is produced through them
“the final common path”.
o In brainstem and spinal cord.
Sensory neurons collect and pass information to interneurons. These link to motor neurons
which pass information to command muscles to move.
Types of glial cells:
Ependymal cells line the brain’s ventricles and make
CSF.
Astroglia (star-shaped glia), provide structural support
and nutrition to neurons.
Microglia (tiny glia) fight infection and remove debris.
Oligodendroglia (few branches) insulate neurons in the
CNS.
Schwann cells insulate sensory and motor neurons in
the PNS. This insulation is myelin.
Gray, white, and reticular matter
Gray matter consists of capillairies and neuronal cell bodies.
White matter consists largely of axons that extend from these
cell bodies to form connections between neurons in other brain
areas. These axons are myelinated. Reticular matter contains a
mixture of cell bodies and axons.
Layers, nuclei, nerves and tracts
Large, well- defined groups of cell bodies in the CNS form either
layers of nuclei. Within the peripheral nervous system (PNS),such are called ganglia. Tracts (fiber
pathways) are large collections of axons projecting toward or away from a nucleus of layer in the
CNS. Tracts carry information from one place to another within the CNS. Fibers and fiber pathways
that enter and leave the CNS are called nerves. but once they enter the central nervous system,
they, too, are called tracts.
3.5: the brainstem
The brainstem begins where the spinal cord enters the skull and extends
opward into the lower areas of the forebrain. It has 3 main regions: the
diencephalon, the midbrain and the hindbrain.
In the brainstem are many cranial- nerve nuclei that converge
(samenkomen) as its core and send their axons to the head muscles. The
brainstem core consists of those cranialnerve nuclei and other nuclei
that mediate a variety of regulatory functions.
Bundles of sensory nerve fibers from the spinal cord pass through
posterior regions (achterkant) of the brainstem on their way to the forebrain
Motor fibers from the forebrain pass through anterior regions (voorkant) of the brainstem on
their way to the spinal cord.
1. The hindbrain: the principal hindbrain structures integrate both voluntary and involuntary body
movement and contribute to sleep- wake cycles.
The most distinctive hindbrain structure is the
cerebellum.
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