1. The Nervous System

3. SWBAT Differentiate between the central and peripheral nervous system
Recognize smaller units of the peripheral system
Describe the structure and function of a neuron

4. General Functions of the Nervous System
Sensory: gathers info about changes occurring within and around the body; sensory receptors, at ends of peripheral nerves, send signals to CNS
examples – light, oxygen levels, body temperature
Integrative: information is “brought together,” interpreted, to create sensations, create thoughts, add to memory, make decisions, etc.
Motor: sending of signals to muscles and/or glands to elicit a response
Bottom Line = Maintenance of Homeostasis

5. Mystery Diagnosis 2nd half

6. Organs of the nervous system can be divided into two groups:
The central nervous system (CNS) is composed of the brain and spinal cord. These neurons cannot regenerate if damaged.

7. The peripheral nervous system (PNS) is made up of peripheral nerves that connect the CNS to the rest of the body. These neurons can regenerate if damaged.
31 pairs of spinal nerves
12 pairs of cranial nerves

8. Peripheral Nervous System
PNS can be subdivided into 2 divisions:
(1) Autonomic
Cranial & spinal nerves connecting CNS to heart, stomach, intestines, glands
Controls unconscious activities

9. Peripheral Nervous System
(2) Somatic
Cranial & spinal nerves connecting CNS to skin & skeletal muscles
Oversees conscious activities

10. Organization of Nervous System
Central Nervous System
Peripheral Nervous System
Brain & spinal cord
Autonomic N.S.
Somatic N.S.

11. Peripheral Nervous System
Autonomic division of the nervous system can be subdivided into 2 divisions:
(1) Parasympathetic
Decreases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle
Increases digestion, pupil size, urinary output
“rest and digest”
(2) Sympathetic
Decreases digestion, pupil size, urinary output
Increases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle
“fight or flight”

12. Parasympathetic vs. Sympathetic Divisions

14. Nervous Tissue is composed of two major cell types: neurons and neuroglial cells.

15. Neurons are made up of a cell body, dendrites, and axons.
Dendrites receive information.
Axons send information.
Larger axons are
enclosed by sheaths
of myelin produced
by Schwann cells.
Narrow gaps in the myelin sheath between Schwann cells are called nodes of Ranvier.

16. Nerves are cable-like bundles of axons.
Neuroglial cells provide physical support, insulation (myelin), and nutrients for neurons.

17. Learning Targets By end of this lesson, you should be able to:
List and describe the ways of categorizing neurons based on structure.
List and describe the ways of categorizing neurons based on function.
Label the parts of a neuron.

18. Classification of Neurons
Neurons can be classified based on function or by structure.
Structure:
(1) Multipolar
Many processes arising from cell body
Brain or spinal cord
(2) Bipolar
2 processes (1 from each end of cell body)
Ear, eyes, nose
(3) Unipolar
Single process extends from cell body
Outside of brain & spinal cord

19. Classification of Neurons
Classifying by Function:

20. Classification of Neurons (by function)
Sensory Neurons – (afferent) have specialized receptor ends that sense stimuli and then carry impulses from peripheral body parts to brain or spinal cord.
Can be unipolar or bipolar.

21. Interneurons – lie entirely within the brain or spinal cord; direct incoming sensory impulses to appropriate parts for processing and interpreting.
Motor Neurons – (efferent) carry impulses out of the brain or spinal cord to effectors (muscles, glands).
Interneurons and motor neurons are multipolar.

22. Two Mild Disorders
Research and write a short brief on these two disorders.
Shingles
Essential Tremors

23. Major Nervous System Diseases
Number of Cases
Cost per year
Chronic Pain
97,000,000
$100 billion
Hearing Loss
28,000,000
$56 billion
Depression Disorders
18,700,000
$30.4 billion
Alzheimer's Disease
4,000,000
$90 billion
Stroke
3,800,000
$40 billion
Epilepsy
2,500,000
$3.5 billion
Traumatic Head Injury
2,000,000
$25 billion
Schizophrenia
$32.5 billion
Parkinson's Disease
1,000,000 to 2,000,000
Multiple Sclerosis
350,000
$2.5 billion
Traumatic Spinal Cord Injury
250,000
$5 billion