Central Nervous System 1-2 min interruption of blood flow may impair brain
cells
Brain & Spinal Cord
>4 min w/o oxygen ! permanent damage
Brain
besides O2 must get continuous supply of glucose
one of largest organs in body:
very little in reserve
men: 1,600 g (3.5 lbs)
decrease in glucose:
women: 1,450g (3.2 lbs)
dizziness
[size is proportional to body size not intelligence convulsions
! Neanderthals had larger brains than us!!] unconsciousness
early thoughts on function of brain:
The Brain is Subdivided Into:
ancient Greeks weren’t particularly impressed with the brain
where snot was generated
cooling device for blood 1. Cerebral Hemispheres (60% of brain mass)
neurons divide only during prenatal development and a few months - “human” part: thought, creativity,
after birth communication
after that they increase in size, but not numbers 2. Diencephalon moods, memory, manages internal
environment
one of most metabolically active organs in body epithalamus
thalamus
comprises only 2% of total body weight it yet hypothalamus
! gets 15% of blood 3. Cerebellum – coordinating movement and balance
!consumes 20% of our oxygen need at rest 4. Brain Stem – oldest and smallest region, basic bodily
(more when mentally active) functions = vegetative functions
midbrain
blood flow and O2 increase to active brain areas pons
medulla
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 1 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 2
cardiac reflex center
Some General Terminology for CNS: rate and force of heartbeat
vasomotor control center
gray matter = thin myelin; mostly cell bodies controls diameter of blood vessels
dendrites & synapses controls the distribution of blood to specific organs
controls blood pressure
-outer layer of brain = cortex
-inner layer of spinal cord respiratory center
-nuclei: small areas of gray matter deeper inside the
regulates the rate and depth of breathing
brain
polio especially affects this center in medulla
! resp failure (iron lungs)
White matter = thick insulation; mostly axons
also contains many nonvital reflex centers (nuclei):
-inner layers of brain: nerve tracts = bundles of
speech
axons that interconnect various parts of the brain
swallowing
-outer layer of spinal cord
vomiting
coughing
Brain Stem sneezing
hiccuping
1. Medulla
2. Pons
lowest portion of brainstem
just above medulla
continuous with the spinal cord
bridge connecting spinal cord with brain and parts
all ascending and descending tracts from spinal of brain with each other
cord and brain = white matter
contains 2 centers that help to regulate breathing
most tracts cross over as they pass through the
medulla ! pneumotaxic center
! apneustic center
helps control several vital functions
! contains important autonomic reflex centers also contains nuclei that affect sleep and bladder
control
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 3 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 4
, Parkinsons Disease
3. Midbrain progressive loss of motor function
begins in 50’s or 60’s
can be hereditary
in the form of 4 lobes above and behind pons due to degeneration of dopamine releasing neurons in
= Corpora Quadrigemina substantia nigra (inhibitory neurons)
leads to hyperactivity of basal nuclei and involuntary muscle
contractions
upper 2 lobes = Superior Colliculi results in shaking hands, facial muscles become rigid, range of
motion decreases
develops smaller steps, slow shuffling gait with forward bent
control center for some visual reflexes: posture and a tendency to fall forward
speech becomes slurred, handwriting illegible
a. pupillary reflex
b. reflex centers for coordinating eye
movement with head and neck 4. Reticular Formation (~Reticular Activation System)
movement in response to visual
stimuli diffuse system of interconnecting fibers extending
through several areas of brain including brain
lower two lobes = Inferior Colliculi stem
-comprises a large portion of entire brainstem
control center for some auditory reflexes: -extends into spinal cord and diencephalon
-interlacing of gray and white matter
a. reflex centers for movements of
head and trunk in response to Functions of RAS - both sensory and motor
auditory stimuli to locate sound
1. Sleep and consciousness
b. startle response to loud noises
maintains consciousness and awakens from
also contains: sleep ! alarm clock
barbiturates depress RAS, decrease alertness &
substantia nigra ! suppresses unwanted produce sleep
muscle contractions
amphetamines stimulate RAS producing wakefulness
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 5 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 6
general anesthetics may produce unconsciousness by and intermediate mass
depressing RAS
falling asleep may be caused by specific mainly a sensory relay center
neurotransmitters that inhibit RAS
! “Rome of the Nervous System”
2. helps control muscle tone, balance or
“gateway to cerebral cortex”
and posture during body movements
! main relay station for sensory impulses
3. filters flood of sensory input that reach cerebral cortex from spinal
(=habituation) cord, brain stem and cerebellum
highlights unusual signals; disregards rest eg. taste, touch, heat, cold, pain, some smell
(99%) the only sensory signals that can reach the
cortex without going through the thalamus are
LSD interferes ! get flood of sensory stimuli for sense of smell
Diencephalon 3. Hypothalamus
1. Epithalamus part of the brain most involved in regulating
internal environment
includes roof of 3rd ventricle
no blood brain barrier
mainly pineal gland
forms floor and part of lateral walls of 3rd ventricle
2. Thalamus:
a. link between “mind” and “body”
4/5ths of diencephalon
controls and integrates activities of autonomic
1.2” long NS
forms lateral walls of 3rd ventricle means by which emotions express themselves
by altering body functions
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 7 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 8
cells
Brain & Spinal Cord
>4 min w/o oxygen ! permanent damage
Brain
besides O2 must get continuous supply of glucose
one of largest organs in body:
very little in reserve
men: 1,600 g (3.5 lbs)
decrease in glucose:
women: 1,450g (3.2 lbs)
dizziness
[size is proportional to body size not intelligence convulsions
! Neanderthals had larger brains than us!!] unconsciousness
early thoughts on function of brain:
The Brain is Subdivided Into:
ancient Greeks weren’t particularly impressed with the brain
where snot was generated
cooling device for blood 1. Cerebral Hemispheres (60% of brain mass)
neurons divide only during prenatal development and a few months - “human” part: thought, creativity,
after birth communication
after that they increase in size, but not numbers 2. Diencephalon moods, memory, manages internal
environment
one of most metabolically active organs in body epithalamus
thalamus
comprises only 2% of total body weight it yet hypothalamus
! gets 15% of blood 3. Cerebellum – coordinating movement and balance
!consumes 20% of our oxygen need at rest 4. Brain Stem – oldest and smallest region, basic bodily
(more when mentally active) functions = vegetative functions
midbrain
blood flow and O2 increase to active brain areas pons
medulla
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 1 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 2
cardiac reflex center
Some General Terminology for CNS: rate and force of heartbeat
vasomotor control center
gray matter = thin myelin; mostly cell bodies controls diameter of blood vessels
dendrites & synapses controls the distribution of blood to specific organs
controls blood pressure
-outer layer of brain = cortex
-inner layer of spinal cord respiratory center
-nuclei: small areas of gray matter deeper inside the
regulates the rate and depth of breathing
brain
polio especially affects this center in medulla
! resp failure (iron lungs)
White matter = thick insulation; mostly axons
also contains many nonvital reflex centers (nuclei):
-inner layers of brain: nerve tracts = bundles of
speech
axons that interconnect various parts of the brain
swallowing
-outer layer of spinal cord
vomiting
coughing
Brain Stem sneezing
hiccuping
1. Medulla
2. Pons
lowest portion of brainstem
just above medulla
continuous with the spinal cord
bridge connecting spinal cord with brain and parts
all ascending and descending tracts from spinal of brain with each other
cord and brain = white matter
contains 2 centers that help to regulate breathing
most tracts cross over as they pass through the
medulla ! pneumotaxic center
! apneustic center
helps control several vital functions
! contains important autonomic reflex centers also contains nuclei that affect sleep and bladder
control
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 3 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 4
, Parkinsons Disease
3. Midbrain progressive loss of motor function
begins in 50’s or 60’s
can be hereditary
in the form of 4 lobes above and behind pons due to degeneration of dopamine releasing neurons in
= Corpora Quadrigemina substantia nigra (inhibitory neurons)
leads to hyperactivity of basal nuclei and involuntary muscle
contractions
upper 2 lobes = Superior Colliculi results in shaking hands, facial muscles become rigid, range of
motion decreases
develops smaller steps, slow shuffling gait with forward bent
control center for some visual reflexes: posture and a tendency to fall forward
speech becomes slurred, handwriting illegible
a. pupillary reflex
b. reflex centers for coordinating eye
movement with head and neck 4. Reticular Formation (~Reticular Activation System)
movement in response to visual
stimuli diffuse system of interconnecting fibers extending
through several areas of brain including brain
lower two lobes = Inferior Colliculi stem
-comprises a large portion of entire brainstem
control center for some auditory reflexes: -extends into spinal cord and diencephalon
-interlacing of gray and white matter
a. reflex centers for movements of
head and trunk in response to Functions of RAS - both sensory and motor
auditory stimuli to locate sound
1. Sleep and consciousness
b. startle response to loud noises
maintains consciousness and awakens from
also contains: sleep ! alarm clock
barbiturates depress RAS, decrease alertness &
substantia nigra ! suppresses unwanted produce sleep
muscle contractions
amphetamines stimulate RAS producing wakefulness
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 5 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 6
general anesthetics may produce unconsciousness by and intermediate mass
depressing RAS
falling asleep may be caused by specific mainly a sensory relay center
neurotransmitters that inhibit RAS
! “Rome of the Nervous System”
2. helps control muscle tone, balance or
“gateway to cerebral cortex”
and posture during body movements
! main relay station for sensory impulses
3. filters flood of sensory input that reach cerebral cortex from spinal
(=habituation) cord, brain stem and cerebellum
highlights unusual signals; disregards rest eg. taste, touch, heat, cold, pain, some smell
(99%) the only sensory signals that can reach the
cortex without going through the thalamus are
LSD interferes ! get flood of sensory stimuli for sense of smell
Diencephalon 3. Hypothalamus
1. Epithalamus part of the brain most involved in regulating
internal environment
includes roof of 3rd ventricle
no blood brain barrier
mainly pineal gland
forms floor and part of lateral walls of 3rd ventricle
2. Thalamus:
a. link between “mind” and “body”
4/5ths of diencephalon
controls and integrates activities of autonomic
1.2” long NS
forms lateral walls of 3rd ventricle means by which emotions express themselves
by altering body functions
Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 7 Human Anatomy & Physiology: Nervous System -–Central Nervous System, Ziser, Lecture Notes, 2010.4 8
