The nervous system is made up of neurons that transmit signals between the central nervous system (CNS) and peripheral nervous system (PNS). The CNS contains the brain and spinal cord, which coordinate sensation, movement, and homeostasis. The PNS connects the CNS to sensory receptors and effector organs. Neurons communicate via synapses using neurotransmitters like serotonin and dopamine. The CNS controls voluntary and involuntary functions while the PNS connects to sensory organs and muscles.
3. OO BODY
A collection of systems
SYSTEM
Several organs working together;
each system has one major role
ORGAN
A distinct body part that carries
out one or more main functions
TISSUE
A group of similar cells that
carry out a specialized job
CELL
ORGANELLE
The basic building block of all
living things, plant or animal
Specialized structures inside a
cell that have specific functions
5. Stimulus
Any change inside or
outside your body that
brings about a response
Homeostasis
Regulation of steady
conditions inside the
body
6. Neurons
Building blocks of the nervous system
100 billion neurons in your brain alone
30,000 on a pinhead
They communicate with each other
thousands of times a second.
Bundles of neurons make up nerves
7.
Central Nervous System =
Brain + Spinal Cord
Peripheral Nervous System =
Nerves to rest of body
8. 3 Types of Nerve Cells
Sensory Neurons
Receive information form a sensory receptor
and send impulses to the CNS
Interneurons
Relay impulses from sensory neurons to
motor neurons
Motor Neurons
Carry impulse from the CNS to muscles and
glands through out the body
9. Parts of a
Neuron
3 MAIN PARTS
Dendrites - receive
messages from other
neurons
Cell Body – nucleus is
found here
Axon - sends messages
to other neurons
12. Space between each neuron
Neurotransmitters are the messengers that
travel across each synapse
They are chemical signals that neurons use to
talk to each other, which is what makes your
brain work. They help determine how you feel,
think and act.
13. Neurotransmitters
Serotonin - involved in mood (such as helping you
to feel happy), sleep, mental health, blood pressure
and heartbeat.
Dopamine - important in helping to regulate
physical movement, pleasure, and thought.
Missing in patients with Parkinson's Disease.
14. Neurotransmitters
• Acetylcholine - involved in regulating
muscles, memory, mood, sleep, and
organs (like the heart).
– Lowered amounts associated with
Alzheimer’s Disease
16. Cerebrum
Largest part of the brain
Interprets impulses from
the senses
Responsible for:
thinking and learning
creativity
five senses
memory and emotion
problem-solving
decisions
17. Cerebellum
Coordinates voluntary
muscle movement
Helps maintain balance
When a ball is thrown to
you, the cerebellum
coordinates the proper
response to prevent injury
18. Brainstem
Controls involuntary
actions
Connects the brain to the
spinal cord
Regulates heart rate,
breathing, swallowing,
blinking, and more
Made up of:
the midbrain
Pons
medulla
19. Made up of bundles of
neurons
Carries impulses to and
from the brain
Together, the brain and
spinal cord make up the
Central Nervous System
(C.N.S.)
Fun fact:
The spinal cord is about
45 cm long in men and 43
cm long in women.
20. Peripheral Nervous System
(P.N.S.)
Connects the C.N.S. with the
rest of the body
• sensory nerves take impulse
from stimulus (sensory
receptors) to the CNS
• motor nerves take impulse
from the CNS to the muscles
and glands that take action.
21. Reflex
REFLEX
An involuntary, automatic response to a stimulus
controlled by the spinal cord
Like when the doctor uses the rubber mallet on
your tendon below your knee
Movement when someone unexpectedly throws
something at you
22. Reflex Arc
When the body receives a painful stimulus (stepping
on a nail, touching a hot surface, etc), the body
responds super-fast.
Path of reflex arc:
STIMULUS sensory receptor sensory nerve
spinal cord (interneuron) motor nerve
muscle RESPONSE
An impulse continues up to the brain to be interpreted by
the cerebrum, BUT, meanwhile the affected area has
already produced a response!
23. Senses
Vision
Sensory Receptors
Rods sense brightness
Cones sense color
The retina, in the back of your eye, has cells that
are sensitive to light. They connect directly to your
brain.
24. Senses
Hearing
Sound waves make your
eardrum vibrate.
Small bones in your ear
vibrate (hammer, anvil,
stirrup)
Vibrations go through the
snail-like cochlea, which
turns them into nerve
impulses to your brain.
25. Taste
10,000 taste buds in your
mouth
Your tongue picks up four
types of taste:
•
•
•
•
sweet
sour
bitter
salty
Sweet and salty are least
sensitive
Bitter ones are most
sensitive
Senses
26. Senses
Smell
Odor particles drift into your nose
Stimulate sensory receptors –
olfactory cells – in nasal passages
Sensory receptors send impulses
to your brain to be interpreted.
27. TOUCH
There are at least six
types of touch receptors
in your skin:
• Hot
• Cold
• Pain
• Pressure
• Touch
• Fine touch
Senses