Science 5.1 knp pdf

Chapter 5 - Section 1

Nervous System

Ner vous System
!Any internal or external change that brings
about a response is called a stimulus

Ner vous System

!Noise, light, the smell of food, and the
temperature of the air are all stimuli from outside
your body.

Ner vous System

!Noise, light, the smell of food, and the
temperature of the air are all stimuli from outside
your body.

!Chemical substances such as hormones are
examples of stimuli from inside your body.

Keeping ever y thing in order
!The regulation of steady, life-maintaining
conditions inside an organism, despite changes in
its environment, is called homeostasis.

Keeping ever y thing in order
!The regulation of steady, life-maintaining
conditions inside an organism, despite changes in
its environment, is called homeostasis.

!Examples:
!Regulating breathing
!Regulating heartbeat
!Regulating digestions

Neurons are made up of a cell body and branches
celled dendrites and axons.

Axons carry impulses away from the cell body. The axon
branches at the end to send the signal to many other
muscles, neurons, or glands.

Types of Ner ve Cells
!Motor Neurons ~ Sensory Neurons ~ Interneurons


!Sensory neurons – receive information and send
impulses to the brian or spinal cord, where…



!Interneurons – relay these impulses to…



!Interneurons – relay these impulses to…

!Motor neurons – conduct impulses from the brain or
spinal cord to muscles or glands throughout the body.

Synapses
 Tomove from one neuron to the next, an impulse
crosses a small space called a synapse.

Synapses
!When an impulse reaches the end of an axon,
the axon releases a chemical.

Synapses

!This chemical flows across the synapse and
stimulates the impulse in the dendrite of the next
neuron.

Synapses

!This chemical flows across the synapse and
stimulates the impulse in the dendrite of the next
neuron.

!Your neurons are adapted in such a way that
impulses move in only one direction.

The Central Ner vous System

!The central nervous
system is made up of the
brain and spinal cord.

CNS – The Brain
!The brain coordinates all of your body activities.

CNS – The Brain

!Made of 100 billion neurons

CNS – The Brain


!WHAT?!?! 100 billion.....
▪That is absolutely.....

CNS – The Brain



!And that is only 10% of all the neurons in the human body.

CNS – The Brain



!And that is only 10% of all the neurons in the human body.

!The brain is surrounded by a bony skull and 3 membranes
and a layer of fluid.

CNS – The Cerebrum
!The cerebrum is the largest part of brain

!This is where…
!thinking takes place
!impulses from the senses are interpreted
!memory is stored
!movements are controlled

!This is where…
!thinking takes place
!impulses from the senses are interpreted
!memory is stored
!movements are controlled

!The outer layer, called the cortex, is marked by
many ridges and grooves (increasing the surface
area).

CNS - Cerebellum
!What is interpreted in the cerebellum?
!Stimuli from the eyes and ears
!Stimuli from muscles and tendons

CNS - Cerebellum
!What is interpreted in the cerebellum?
!Stimuli from the eyes and ears
!Stimuli from muscles and tendons

!The cerebellum interprets this information and
uses it to coordinate voluntary muscle movement,
maintain muscle tone, and helps maintain
balance.

CNS – The Brain Stem
!The brain stem is located at the base of the brain
and extends from the cerebrum and connects the
brain and the spinal cord

!Ismade up of the midbrain, the pons, and the
medulla

medulla
!The midbrain and pons act as pathways to connect
different parts of the brain with each other.

medulla
!The midbrain and pons act as pathways to connect
different parts of the brain with each other.
!The medulla controls involuntary actions (heartbeat,
breathing, blood pressure). It is also involved in actions
such as coughing, sneezing, vomiting.

CNS – The Spinal Cord
!The spinal cord is an extension of the brain stem.


!It contains bundles of neurons that carry
impulses between all parts of the body and the
brain.


!It contains bundles of neurons that carry
impulses between all parts of the body and the
brain.

!An adult spinal cord is about the width of an
adult thumb and is about 43 cm long.

The Peripheral Ner vous System


!Yourbrain and spinal cord are connected to the
body by the peripheral nervous system.


!Yourbrain and spinal cord are connected to the
body by the peripheral nervous system.

!The PNS is made up of 1 pairs of nerves from
2
your brain called cranial nerves and 31 pairs
from your spinal cord called spinal nerves.


!Spinalnerves are made of bundles of sensory
and motor neurons bound together.



!In this way a single spinal nerve can have
senses going to and from the brain.



!In this way a single spinal nerve can have
senses going to and from the brain.

!Some nerves contain only sensory neurons, and
some contain only motor neurons, but most
nerves contain both types of neurons.

PNS – Somatic and Autonomic
Systems

Systems
!Somatic System
controls voluntary actions

Systems
!Somatic System
controls voluntary actions
!It is made up of cranial
and spinal nerves that go
from the CNS to your
skeletal muscles.

Systems
!Somatic System  Autonomic System
controls voluntary actions controls involuntary actions
!It is made up of cranial (such as heart rate,
and spinal nerves that go breathing, digestion,
from the CNS to your glandular functions)
skeletal muscles.

Safety and the Ner vous System


!Any injury to the brain or the spinal cord can be
serious.


serious.

!A severe blow to the head can bruise the brain
and cause temporary or permanent loss of
mental and physical abilities.


serious.

!A severe blow to the head can bruise the brain
and cause temporary or permanent loss of
mental and physical abilities.

!Spinal cord injuries can be just as dangerous as
a brain injury.


 Injury
to the spine can bring about damage to
nerve pathways and result in paralysis, which is
the loss of muscle movement.

Safety - Reflexes
!You experience a reflex when you touch something
hot, or when you cough or vomit.

Safety - Reflexes

!Reflex – an involuntary automatic response to a
stimulus.

Safety - Reflexes

stimulus.

!You cannot control them because they occur before
you are aware of them.

Safety - Reflexes

stimulus.

!You cannot control them because they occur before
you are aware of them.

!They involve a simple nerve pathway called a
reflex arc.

Safety - Reflexes
!Reflexes allow your body to respond without
having to think about what action to take.

Safety - Reflexes

!Reflex responses are controlled in your spinal
cord, not your brain.

Safety - Reflexes

!Reflex responses are controlled in your spinal
cord, not your brain.

!Yourbrain acts after the reflex to help figure out
what to do next to stop the pain.

Drugs and the Ner vous System

!Many drugs, such as alcohol and caffeine,
directly affect your nervous system.


!Many drugs, such as alcohol and caffeine,
directly affect your nervous system.

!When swallowed, alcohol passes directly
through the walls of the stomach and small
intestine into the circulatory system.


!This drug slows the activities of the central
nervous system and is classified as a
depressant.


!This drug slows the activities of the central
nervous system and is classified as a
depressant.

!Heavy alcohol use destroys brain and liver cells.


•Caffeine is another drug
that can affect your
nervous system.


•Caffeine is another drug
that can affect your
nervous system.
•Too much caffeine can
increase heart rate and
aggravates restlessness,
tremors, and insomnia in
some people.

Science 5.1 knp pdf

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