1. The Nervous System

2. Functions of the Nervous System
1. Sensory input – gathering information
To monitor changes occurring inside and outside the body (changes = stimuli)
2. Integration –
to process and interpret sensory input and decide if action is needed.
3. Motor output
A response to integrated stimuli
The response activates muscles or glands

3. Neuron Anatomy
Cell body
Nucleus
Large nucleolus

4. Neuron Anatomy Extensions outside the cell body
Dendrites – conduct impulses toward the cell body
Axons – conduct impulses away from the cell body (only 1!)
Figure 7.4a

5. Nerve Fiber Coverings
Schwann cells – produce myelin sheaths in jelly-roll like fashion
Nodes of Ranvier – gaps in myelin sheath along the axon
Figure 7.5

6. Application In Multiple Scleroses the myelin sheath is destroyed.
The myelin sheath hardens to a tissue called the scleroses.
This is considered an autoimmune disease.
Why does MS appear to affect the muscles?

7. The Nervous System Major division - Central vs. Peripheral
Central Nervous System
Peripheral Nervous System
Major division - Central vs. Peripheral
Central or CNS- brain and spinal cord
Peripheral- nerves connecting CNS to muscles and organs

8. Peripheral Nervous System
3 kinds of neurons connect CNS to the body
sensory
motor
interneurons
Motor - CNS to muscles and organs
Sensory - sensory receptors to CNS
Interneurons: Connections Within CNS
Spinal
Cord
Brain
Nerves
key words: peripheral nervous system

9. Peripheral Nervous Systemk e l t a ( o m i c ) y p h P r s A u n N v
key words: peripheral nervous system; skeletal nervous system; somatic nervous system; autonomic nervous system; sympathetic nervous system; parasympathetic nervous system

10. Somatic System Nerves to/from spinal cord control muscle movements
somatosensory inputs
Muscle
Motor
Neuron
Interneuron
Skin receptors
Sensory
Brain

11. Autonomic System Two divisions: Control involuntary functions
sympathetic
Parasympatheitic
Control involuntary functions
heartbeat
blood pressure
respiration
perspiration
digestion
Can be influenced by thought and emotion

12. Sympathetic “ Fight or flight” response
CENTRAL NERVOUS SYSTEM
Brain
Spinal
cord
SYMPATHETIC
Dilates pupil
Stimulates salivation
Relaxes bronchi
Accelerates heartbeat
Inhibits activity
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Stimulates ejaculation
in male
Sympathetic
ganglia
Salivary
glands
Lungs
Heart
Stomach
Pancreas
Liver
Adrenal
gland
Kidney
“ Fight or flight” response
Release adrenaline and noradrenaline
Increases heart rate and blood pressure
Increases blood flow to skeletal muscles
Inhibits digestive functions
keywords: sympathetic nervous system; fighlt or flight response

13. Parasympathetic “ Rest and digest ” system
CENTRAL NERVOUS SYSTEM
Brain
PARASYMPATHETIC
Spinal
cord
Stimulates salivation
Constricts bronchi
Slows heartbeat
Stimulates activity
Contracts bladder
Stimulates erection
of sex organs
Stimulates gallbladder
Gallbladder
Contracts pupil
“ Rest and digest ” system
Calms body to conserve and maintain energy
Lowers heartbeat, breathing rate, blood pressure
key words: parasympathetic nervous system; rest and digest system

14. Summary of autonomic differences
Autonomic nervous system controls physiological arousal
Sympathetic
division (arousing)
Parasympathetic
division (calming)
Pupils dilate EYES Pupils contract
Decreases SALVATION Increases
Perspires SKIN Dries
Increases RESPERATION Decreases
Accelerates HEART Slows
Inhibits DIGESTION Activates
Secrete stress
hormones
ADRENAL
GLANDS
Decrease secretion
of stress hormones
key words: sympathetic nervous system; parasympathetic nervous system