Transcript Central Nervous System - York Catholic District School Board

THE CENTRAL NERVOUS
SYSTEM (CNS): Brain and
Spinal Cord
BRAIN Fun Facts
 The brain weighs
approximately 3 pounds (1.4
kg)
 The brain can send out a
message traveling at 289 km/s
 It has about 100 billion
neurons
 Scientists believe there are
more neurons in the human
brain than there are stars in
the Milky Way!
1. BRAINSTEM
1.
MIDBRAIN: involved
with visual reflexes
2.
PONS: controls certain
respiratory functions
3.
MEDULLA
OBLONGATA:
regulates heart and
lung functions,
swallowing, vomiting,
coughing, and sneezing
2. CEREBELLUM
-coordinates muscle and
skeleton movement to
maintain posture, balance, and
muscle tone
3. CEREBRUM
 the largest part of the brain
 2 hemispheres: RIGHT and LEFT.
 has an outer portion called the “cerebral cortex” (area of
conscious decision making)
Lateralization
 The fact that certain activities are the almost
exclusive domain of one of the 2 hemispheres.
 The left hemisphere is geared towards language,
math, and logic
 The right hemisphere is geared towards musical,
artistic and other creative endeavors.
 Most individuals with left cerebral dominance are
right-handed. (Left-handed people have more
right cerebral dominance)
Right or left-brained?
The Stroop test
 Right brain – identifies the colour itself
 Left brain – reads the colour word
 For most people, this is a challenging
task, because there is a R-brain/Lbrain conflict! Which side to you tend
to use for this test?
3. CEREBRUM
 Each hemisphere is divided into four lobes
 Frontal lobe: controls voluntary motor movements,
emotional expression, and moral behavior
 Temporal lobe: controls memory, equilibrium, emotion,
and hearing
 Parietal lobe: controls and interprets the senses and taste
 Occipital lobe: controls vision and various forms of
expression
Lobes of the
cerebrum
What is the name of
this region?
What is this
called?
The Story of Phinaeus Gage
 Scientists learned a lot
about the functions of the
frontal lobe due to the
bizarre accident that left a
young railroad worker by
the name of Phinaeus
Gage with a severely
damaged frontal lobe.
4. DIENCEPHALON

deep part of the brain

contains the thalamus and the
hypothalamus

thalamus: receives, sorts and
sends messages from the
sense organs (eg. eyes, ears)
to cerebral cortex

hypothalamus: controls heart
rate, blood pressure, temp.
regulation, water and
electrolyte balance, digestive
functions, and glandular
activities
Cerebrospinal Fluid (CSF)
 watery fluid that contains various compounds
 flows throughout the brain and around the spinal
cord
 cradles and cushions the brain
 also contained in VENTRICLES (cavities) in the
brain
Meninges
Meninges: (from brain to cranium) – pia mater,
arachnoid layer, dura mater (PAD)
Meningitis
- an inflammation of the meninges
-caused by viruses or bacteria
-symptoms: fever, headache, and stiff
neck
-can be fatal
Meninges
 dura mater
 covers entire length of the spinal cord
 contains channels for blood to enter brain tissue
 space between dura mater and the bones of the spinal
cord is called the “epidural space”
 arachnoid membrane
 weblike structure that runs across the space containing
the cerebrospinal fluid
 pia mater
 thin membrane containing many blood vessels that
nourish the spinal cord
Brain injury
 Why do we wear helmets?
 A severe concussion can
lead to coma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
PET scan (Positron
Emission
Tomography)
-The brain is injected
with radioactive glucose
-The more active the
parts of the brain are,
the more glucose is
taken up, and the more
“blue” the brain areas
are
-This technique is also
used to analyze
Alzheimer’s and stroke
patients.
brain activity
Before cocaine use,
brain is less active.
After cocaine use, brain is more active.
© Science VU/Visuals Unlimited
Spinal Cord
 extends from the base of the brain to the first lumbar vertebra
in the lower back
 contained within the vertebral column
 Vertebral canal – space that contains the spinal column
 protected by the vertebral column, the CSF, and by the spinal
meninges
 Spina bifida
 defect in the spinal column in which the spinal cord
protrudes outside the vertebrae
 Mild cases are visible only by X-ray
 Causes varying degrees of paralysis, lack of feeling and
movement
Spinal Cord Injuries
 if spinal cord is severed, paralysis will occur and
affect the area below the injury
 Paralysis – loss of movement and sensation
 Three common types:
 Hemiplegia – paralysis on one side of the body, usually
due to a stroke
 Paraplegia – paralysis from the waist down, often caused
by a car/motorcycle accident, fall, gunshot or stab
wound, or sports injury
 Quadriplegia – paralysis from the neck down (injury is
below the C4 vertebra)