Title: The History of the study of the Brain
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2The History of the study of the Brain
- Early brain studies used the method of
phrenology. - Phrenology examination of the skull where bumps
and indentations are used to make a mental map
and were then related to the character of that
person. - The end of World War II and the massive quantity
of brain injuries leads many people to examine
the brain on a deeper level. - New technologies like the MRI have allowed
doctors to observe the brain in operation in
incredible detail.
http//skepdic.com/phren.html
3Overview The Nervous System
- Central Nervous System (CNS) Brain Spinal
Cord - Peripheral Nervous System Nerves to rest of
body - Sensory nerves carry messages from the body to
the brain - Motor nerves carry messages from the brain to the
body
4Central Nervous System - Anatomy Function -
5The Human Spinal Cord
6The Spinal Cord
- The main pathway for information connecting the
brain and peripheral nervous system - - Conducts sensory information from the
peripheral nervous system (both somatic and
autonomic) to the brain. - - Conducts motor information from the brain
to the various effectors (skeletal muscles,
cardiac muscle, smooth muscle, glands). - Serves as a minor coordinating center responsible
for some simple reflexes (e.g., withdrawal
reflex). - The average spinal cord is 45 cm long in men and
43 cm long in women. The spinal cord weighs
approximately 35 g.
7The Spinal Cord Vertebrae
- The human spinal cord is protected by the bony
spinal column. The spinal column is made up of
bones called vertebrae. - The spinal cord is located in the vertebral
foramen and is made up of 30 segments 7
cervical, 12 thoracic, 5 lumbar, 5 sacral and 1
coccyx. A pair of spinal nerves exits from each
segment of the spinal cord.
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9- The vertebral column provides structural support
for the trunk and surrounds and protects the
spinal cord. - The vertebral column also provides attachment
points for the muscles of the back and ribs. - The vertebral disks serve as shock absorbers
during activities such as walking, running, and
jumping. They also allow the spine to flex and
extend. Common injury Ruptured Disk
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12Famous Spinal Cord Injuries
- Mike Utley 1991 Detroit Lions Offensive Lion
fractured his 6th and 7th cervical vertebrae.
http//www.mikeutley.org/images/mike.gif
13- Christopher Reeves
- Well, I totally decimated my first cervical
vertebra and my second, and so my body and my
spine and my head were not connected. Only my
neck muscles were holding my head on, and
fortunately I didn't suffer any brain damage, at
least none that I can detect. laughter But, you
know, that's what they tell me at any rate. But
they literally had to put my head back on my
body, and a wonderful surgeon, Dr. John Jane at
the University of Virginia, was the one who
operated on me, and they had to make it up. They
had never done anything like this before, because
this is what is called a hangman's injury, you
know, like if you get dropped through the trap
door and then cut down, sent to rehab and told to
have a nice life.
http//record.wustl.edu/archive/2000/12-01-00/phot
os/reeves.jpg
14How does the brain protect itself?
15Four ways the brain protects itself
- 1. Skull -
- 2. Meninges
- 3. Cerebrospinal Fluid
- 4. Blood Brain Barrier (BBB)
16Central Nervous System- The Coverings of the
Brain (Shocks)
Meninges
- Both the brain and the spinal cord are covered in
three continuous sheets of connective tissue, the
meninges. - The dura mater (the dura) the outer layer
- The arachnoid the middle layer
- The pia mater (the pia) the inner layer
- The meninges PAD the brain
17http//www.baltimoresun.com/media/photo/2004-05/12
819309.jpg
18Central Nervous System- Cerebrospinal Fluid
(CSF) -
The entire surface of central nervous system is
bathed by a clear, colorless fluid, called
cerebrospinal fluid (CSF). The CSF is contained
within a system of fluid-filled cavities called
ventricles.
- The total volume of CSF is 125-150 ml
- Normal resting pressure of the CSF is between
150-180 mmH2O. - Total production of CSF is about 400-500 ml/day
(about 0.36 ml/min)
19Central Nervous System- Cerebrospinal Fluid
(CSF) -
- What does the CSF do?
- Protection The CSF protects the brain from
damage by buffering the brain. - Buoyancy The pressure at the base of the brain
is reduced by immersing in the CSF. - Excretion of waste products The one-way flow
from the CSF to the blood takes potentially
harmful metabolites, drugs and other substances
away from the brain. - Endocrine medium for the brain The CSF serves to
transport hormones to other areas of the brain.
20Central Nervous System - Blood-Brain Barrier
(BBB) -
21What is the Blood-Brain Barrier (BBB) ?
The barrier exists between the blood and the
brain
22BBB History
- The late 19th century, Paul Ehrlichs experiment
Certain dyes (e.g., a series of aniline
derivatives) administered intravenously to small
animals stained all the organs except the brain
The brain has a lower affinity for the dye than
the other tissues. - In 1913, Edwin G. Goldmans experiment
- The dye trypan blue, directly injected into
the cerebrospinal fluid of rabbits or dogs,
readily stained the entire brain but did not
enter the bloodstream to stain the other internal
organs The CNS is separated from the blood by a
barrier of some kind.
23BBB History
- The late 1960s
- Electron microscopy confirmed the hypothesis
that brain capillaries provide the anatomical
basis of the BBB - Recent studies
- - The BBB is present in all vertebrate brains
- - The BBB is laid down within the first 3
months of human fetal life
24BBB FunctionNeuroprotective Role
25BBB Function
- Physical Barrier
- To protect the brain tissues from foreign
substances or certain chemicals in the blood
that may injure the brain
Biological Shield or Safeguard
26BBB FunctionNeuroprotective RoleObstacle
to Drug Delivery
27- In order to cross the BBB in
pharmacologically significant amounts, the
therapeutic drugs must have the following
characteristics - Lipid soluble
- Have a molecular weight lt 400 Daltons
- Not be a substrate for a BBB active efflux
transporter
This class of drugs constitutes lt2 of all
potential small molecule drugs. Only few brain
disorders, such as depression, schizophrenia,
chronic pain, and epilepsy, respond to such
drugs. 100 of large molecule drugs and 98 of
small molecule drugs do not cross the BBB.
28Reflection
- Of the four protective functions, which do you
think would be most important in the field of
psychology? Why?