Transcript Nervous System - ABC-MissAngelochsBiologyClass

Regulation:
Nervous System
A World Without Pain
Perry Goldberger, 15, can't
distinguish between hot and cold
and cannot feel pain
Four-year-old
Roberto Salazar does
not feel pain because
of a rare genetic
disorder.
NERVOUS SYSTEM
NERVE
REGULATON
STIMULUS:
Example – heat
From a stove
IMPULSE:
Example – neurons
Send a message to
CNS to tell the hand
To move
RESPONSE:
Example – removing
Hand off the stove
HUMAN
NERVOUS
SYSTEM
Central Nervous
System (CNS) –
brain and spinal
cord
Peripheral Nervous
System (PNS) –
nerves outside the
CNS
Nerve Cells
• Nerve cells = neurons
• Receive impulses and send the
messages to various parts of the body
via Cellular Communication
• Nerve cells make up:
– Nerves
– Brain
– Spinal cord
– Receptors
????
• You accidentally place your hand on a
hot iron and quickly move it away.
– What is the stimulus?
– What is the impulse?
– What is the response?
• What is the difference between the CNS
and PNS?
• What is the function of a neuron?
Neuron Structure
• 1. Cyton- cell body
• 2. Cell nucleus
• 3. Dendrites –
receive impulses
Neuron Structure Cont…
• 7. Axon – carries
impulses away
from the
dendrites
• 6. Myelin Sheath
– fatty covering of
the axon which
speeds up
impulses
• 5. Schwann Cells
(make myelin)
Neuron Structure Cont…
• 9. Terminal Branches
• Synapse – gap where
impulses travel from
the axon of one
neuron to the
dendrites of another
neuron.
• Neurotransmitters –
chemical messengers
that cross the
synapse
Types of Neurons
– Sensory: carry impulses to the CNS
– Motor: carry impulses from the CNS to
other parts of the body such as muscles
– Mixed: contain both
Receptors
• Receive messages
• Found on the cell membrane and are
VERY SPECIFIC!!!
CNS
The Brain
• Cerebrum –
thinking, memory,
voluntary actions,
emotions
• Cerebellum –
coordination and
balance
• Medulla (brain stem)
– involuntary
actions like
breathing and
heartbeat
Spinal Cord
• Mass of nerve cells
• Vertebrae – protect it
• Function –
– relays impulses to and from the brain
– center for some reflex actions
Autonomic Nervous System
• Part of the peripheral nervous system
• Controls involuntary behavior (automatic)
• Examples:
– Breathing
– Heart rate
– Blinking, dilation of pupil
– Production of saliva
– Increases and decreases the rate of these
involuntary behaviors to help maintain
homeostasis
Reflexes- Reflex arc
• Involuntary behavior
• Reflex:
– Receptor (nerve endings in the knee) receive a
message
– Sensory neuron sends to message to the spinal
cord (CNS)
– The interneuron connects the sensory neuron to
the motor neurons
– The motor neuron sends the message to the
muscle in the leg (EFFECTOR)
– Effector then reacts such as a knee jerk
Somatic Nervous System
• Part of the peripheral nervous system
• voluntary behavior
• Examples: movement of skeletal
muscles
Disorders of the Nervous
System
Cerebral Palsy
• Birth disorder that
affects motor
function.
Polio
• a viral pathogen that
weakens muscles
and leads to
paralysis
Stroke
• When a free-floating
blood clot reaches the
brain
• Blood vessel ruptures
in the head/neck
Meningitis
• Inflammation of the meninges (membrane
surrounding the brain and spinal cord)
• Can be viral (not severe) or bacterial
(VERY severe)
• Symptoms come quickly
– Fever and chills, nausea and vomiting,
sensitivity to light, severe headaches
The meningococcal vaccination is
recommended for:
• Adolescents ages 11 - 12 and adolescents
entering high school (about age 15) who
have not already received the vaccination.
• All college freshmen who have not been
vaccinated and are living in dorms.
• Those traveling to countries where
diseases caused by meningococcus are
very common