Download Nervous

-The process by which organisms maintain,
control, and coordinate their internal environment
with a constantly changing external environment
-It is all of the activities that help to
maintain an organism’s
Homeostasis:
“…the ability to maintain relatively
constant internal conditions even
though the external world changes
continuously…”
• Within cells
• Within body
1.Nervous System – nerve control (action/reaction)
2. Endocrine System- chemical control (hormones/receptors)
-Process by which the product of a system shuts
Down a system or limits its operation
Ex: Home heating system
Blood Sugar Level
Shivering
Menstrual Cycle
Homeostasis
Maintained until
another change occurs
System
Limited or
Shut down
Change
Detected/
System turned “on”
System Responds
with production
Homeostasis
achieved
Stimulus- Changes that cause a response
Ex: Light, sound
Response- Reaction to a stimulus
Neuron- Nerve cell that transmits impulses
throughout the body
Dendrites- detect stimulus
Cyton-(Cell body) Contains nucleus and organelles
Axon- Connects cyton to terminal branches
(elongated portion)
Terminal Branches- end of neuron. Secretes
neurotransmitters that allow impulses to jump
over synapses
Synapse- Gap between neurons
Neurotransmitters-special chemical that allows
impulses to jump synapses
Impulse- An electrochemical charge that
transmits information (the message)
Receptor Organ- Organs that receive stimuli
(action)
Ex: Eyes, ears, nose, skin, tongue
Effectors- Muscles or glands that respond
To stimuli (reaction)
Dendrites
Terminal Branches
Nucleus
Axon
Myelin Sheath
Cell body (Cyton)
Synapse
How does the Nervous System maintain
homeostasis?
-by maintaining nerve control (action/reaction)
What are the basic functional units of the human
Nervous System?
-Neurons
-Nerves
-Central Nervous System (CNS)
-Peripheral Nervous System (PNS)
3 Types:
Receive stimuli from the environment
and transmit this information to the
CNS for interpretation.
Sensory receptor organs include: eyes, ears, nose, tongue,
skin
Transmit impulses from the CNS to the
Effectors (muscles and glands) where an
Appropriate response is initiated.
Relay nerve impulses between sensory
and motor neurons.
-A bundle of neurons all together (a tissue). They
transmit impulses over long distances at high
rates of speed.
Cell X is sending
A message to
Cell Y
If a drug was being developed to block the action
Of neurotransmitter A, what shape should the drug have?
-Impulse traveling
-Neurons
“communicating”
Pathway
1. Stimulus
2. Receptor organ
3. Sensory Neurons
Example
Heat from a stove
Nerves in skin of finger
(any sense organ)
Carries impulses to the spinal cord
4. Interneurons
Found in spinal cord. Connect
Sensory to motor
5. Motor Neurons
Carries impulses to effectors
6. Effector
Muscles in arm
7. Response
Pulling finger away from
stove
What does the CNS consist of?
-Brain
-Spinal Cord
What does the CNS do?
-Relays messages
-Processes and analyzes
information (“Command Center”)
How is the CNS protected?
-The brain is protected by the SKULL
-The spinal cord is protected by the VERTEBRAE
How does the brain maintain homeostasis?
-Regulates ALL activity
-Stores memory and interprets what is
happening
Division: Cerebrum
Location: Top/Front (Largest part of brain)
Function: -Regulates conscious, voluntary actions
-Conditioned behaviors (habits) are
centered here
-Site of intelligence, learning, and
judgment
Examples: Thought, memory, reasoning, sense
interpretation, speech
Division:
Cerebellum
Location: Rear of cranium
Function: -Coordinates muscular activities and
balance
Examples: Coordination, walking,
running, fine
motor skills
Division:
Medulla
Location: Base of brain
Function: Coordinates involuntary activities
Examples: Breathing, heart rate, blood pressure,
peristalsis
Structure:
Hypothalamus
Location:
Base of brain
Function:
-(Sensor) Gland that detects
hunger, thirst, fatigue, anger, body
temperature, blood sugar level
Structure: Thalamus
Location: Base of brain
Function:
-Recognizes messages from sense
organs
Medulla
Right Brain
-Controls left
side of the
body
Processes:
-Creativity,
Artistic Ability
-Patterns,
Spatial awareness
It Recognizes:
-Faces
-Places
-Objects
Left Brain
-Controls right
side of body
Processes:
-Analytical and
Mathematical
ability
-Speech, time,
sequences
It Recognizes:
-Letters
-Words
-Numbers
Why is the spinal cord part of the CNS?
-It is continuous with the brain (Connected at
the medulla)
How does the spinal cord maintain
homeostasis?
-It is the center for reflex actions
-Coordinates activity between
brain and body structures
Why is there fluid surrounding the
Brain and Spinal Cord?
-Shock absorbency and nourishment
INVOLUNTARY
Sensory Receptor
(found in sensory organ)
Motor Neuron
(sends impulse to effector)
Effector
(reaction)
Sensory Neuron
(receive stimulus; found in receptor)
Interneuron
(in spinal cord; interprets information)
How fast does this happen?
-Completed BEFORE the cerebrum is even aware
of the initial stimulus!!!
What is the PNS?
-consists of nerves extending throughout the body
How does the PNS maintain homeostasis?
-Receives information for and relays commands
from the CNS
Where is the PNS located?
-Located outside of the CNS
-consists of nerves that control the
VOLUNTARY muscles of the skeleton
-Consists of nerves regulating
INVOLUNTARY (automatic) functions
(actions of glands and involuntary muscles)
Cerebral Palsy:
-brain damage just before or after birth
that affects a person’s ability to control
body movements and muscle coordination
Caused by:
Lack of oxygen to the brain
Treatment: Most damage irreversible
Victims usually undergo extensive
physical therapy and in some cases
surgery is required
Multiple Sclerosis:
-Nerve disorder in which victims suffer from
blurred vision, slurred speech, and shaky
hands due to the fatty coverings of axons
in brain or spinal cord being destroyed.
Caused by: No definite known cause (linked to
Genetics, environmental factors, and
Geographical factors)
Treatment: No cure
Alzheimer’s Disease:
-Victims suffer from memory loss, inability
To think, speak, or care for oneself
Caused by:
No known cause
Treatment: No cure. Usually fatal
Parkinson’s Disease:
-Victims suffer from shaking, poor balance,
and stiffening of muscles due to loss of
function of neurons in brain
Caused by: No known cause
Treatment: No cure.