Download 36.1 The Nervous System Neurons: Basic units of

Chapter 36: Nervous system
36.1 The Nervous System
Neurons: Basic units of the nervous system
Main Idea
Neurons transmit impulses to and from the brain
Neurons are motor,
sensory and
interneurons
Interneurons are
found in the brain
and spinal cord
Nerve impulse has
to travel to the
brain then back
down to the
muscles and bones.
Active Transport
Supporting Detail
3 sodium ions are
pumped out for
every 2 potassium
ions pumped in resulting in a
negative charge
Change in this
charge moves the
impulse down axon.
Impulse crosses
space by opening ca
channels and
exocytosis occurs
enter the next
neuron thru their
ion channels – these
are call
Neurons: a long cell that consists of 3 regions a cell body, dendrites and
axon and conducts an impulse.
Dendrite - branch like extensions of the neuron that receive impulses and carry
them to the cell body.
White matter - Composed of myelin which coats the axons – this area of the brain is
high in axons
Gray matter – areas not covered by myelin – the cell bodies themselves
Synapse – junction between neurons. Impulses must above across this space
Neurotransmitters – chemicals like Ca that cross the barrier and enter the next
cell. Broken down by enzymes
Central Nervous System
Main Idea
CNS controls major functions – often without us knowing
The brain and the
spinal cord – works
with the peripheral
nervous system
Supporting Detail
Peripheral NS
carries impulses
between the body
and CNS
Somatic NS carries
impulse between
skin, CNS and
Skeletal system
Flight – fight
response affects
heart rate and
breathing rate.
Cerebrum – controls all conscious activity.
Cerebellum – located in the back of your brain and controls balance, posture and
coordination
Medulla oblongata: controls involuntary activities such as breathing and heart rate.
Somatic nervous system: contain both sensory and motor nerves.
Reflex: an automatic response to an impulse
Autonomic NS carries impulses from the CNS to internal organs
Sympathetic NS controls many internal processes in times of stress.
Section Assessment 1-5:
1.
Summarize the charge distribution that exists inside and outside of a resting neuron
2.
Outline the functions of the three major parts of the brain.
3.
Contrast the functions of the two divisions of the autonomic nervous system.
4.
How does the Na+ / K+ pump affect ion distribution in a neuron?
5.
Why is it nearly impossible to stop a reflex from taking place?
The inside is more negatively charged than the outside
The cerebrum controls conscious activities – language, intelligence,
memory, movement, senses
The cerebellum controls balance, posture, and coordination
The medulla oblongata controls involuntary activities
The sympathetic nervous system control functions in times of stress
and the parasympathetic controls functions while the body is at
rest.
The pump moves three sodium ions out of the cell for every tw0
potassium ions it pumps into the cell. This moves the negative
charge down the axon to the next cell.
A reflex is an involuntary action that does not involve conscious
control by the brain. You cannot stop it.