1. 2.2
THE NERVOUS SYSTEM

2. The body’s communication systems help maintain homeostasis.
A stimulus causes a response.
Responses can be chemical, cellular, or behavioral.
The nervous system responds to stimuli.

3. The nervous system controls thoughts, movement, and emotion.

4. The nervous system works quickly, using chemical and electrical signals.
interconnected network of cells
signals move through cells
divided into central nervous system (CNS) and peripheral nervous system (PNS)
spinal chord
nerves

5. The nervous system’s two parts work together.
The CNS includes the brain, brain stem, and spinal cord.
The PNS includes four systems of nerves.

6. The CNS processes information.
The brain has three parts.
cerebrum controls thought, movement, emotion

7. Lobes of the Brain
There is a fifth lobe, known as the limbic lobe, that is responsible for emotions

8. The CNS processes information.
The brain has three parts.
cerebrum controls thought, movement, emotion
cerebellum allows for balance
brain stem (reptilian brain) controls basic life functions
Brain stem
midbrain
pons
medulla oblongata

9. The brain stem has three parts. midbrain controls some reflexes
pons regulates breathing
medulla oblongata controls heart function, swallowing, coughing
midbrain
pons
medulla oblongata

10. The spinal cord controls reflexes.
sensory neuron sends impulse to spinal cord
spinal cord directs impulse to motor neuron
does not involve the brain
See simulation with online textbook
interneuron
motor neurons
sensory neuron

11. The PNS gathers and transmits information
links the CNS to muscles and other organs.
The somatic nervous system regulates voluntary movements.

12. The PNS gathers and transmits information
The autonomic nervous system controls involuntary, functions
sympathetic nervous system:
“fight vs. flight”
Involved in all internal adjustments that prepares the body for action or increased levels of stress.
parasympathetic nervous system:
sends impulses that return a body to “normal” functioning after a period of stress is over,
conserves energy

13. Sympathetic Parasympathetic
Fine adjustments made so glands and organs are functioning at levels appropriate to a body at a particular time:
Sympathetic
Parasympathetic
Dilates pupils
Inhibits saliva
Constricts blood vessels
Accelerates heart
Bronchi dilate
Glycogen converts to glucose
Bladder relaxes
Constricts pupil
Stimulates salivation
Dilates blood vessels
Reduces heart rate
Constricts bronchi
Stimulates bile release
Contracts bladder

14. The CNS and PNS pass signals between one another.
Sensory receptor generates impulse.
PNS passes impulse to CNS.
CNS interprets impulse.
CNS passes impulse to PNS.
PNS stimulates a response.

15. Basic Organization
sensory receptor (sensory input)  integration  (motor output)  effector
Sensory Input triggered by stimuli
conduction of signals to processing center
Integration
interpretation of sensory signals within processing centers
Motor output
conduction of signals to effector cells (i.e. muscles, gland cells)

16. Nerves
Nerves, which carry the electrical impulses to various parts of the nervous system, are made up of a bundles of cells, known as neurons

17. Neurons are highly specialized cells.
A neuron has 3 main parts.
cell body contains nucleus and organelles 1
Cell body

18. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles
dendrites receive impulses 2
dendrites

19. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles
dendrites receive impulses
axon carries (transmits) impulses 3
axon

20. Neurons have other structures to transmit signals.
Schwann cell makes up the myelin sheath, which insulates the axon

21. Neurons have other structures to transmit signals.
Schwann cell makes up the myelin sheath, which insulates the axon
Nodes of Ranvier – the gaps between the myelin sheath that speed up the process of transmitting impulses.

22. Neurons have other structures to transmit signals.
Schwann cell makes up the myelin sheath, which insulates the axon
Nodes of Ranvier – the gaps between the myelin sheath that speed up the process of transmitting impulses.
Axon terminal – part through which the impulse leaves.
axon terminal

23. Neurons have other structures to transmit signals.
Schwann cell makes up the myelin sheath, which insulates the axon
Nodes of Ranvier – the gaps between the myelin sheath that speed up the process of transmitting impulses.
Axon terminal – part through which the impulse leaves.
synapse gap between the neuron and the next cell.
synapse

24. Types of Neurons
Sensory Neuron: detect stimuli and transmit signals to the brain and the spinal cord, which are both made up of interneurons.
Interneurons: receive signals from sensory neurons and relay them within the brain and the spinal cord. Process information and pass signals to motor neurons.
Motor neurons: pass messages from the NS to other tissues in the body, such as muscles