The Nervous System

1
The Nervous System

• Chapter 35

2
35-1 Human Body Systems

• Organization of the Body
• Cell
• Tissues-group of cells that perform a similar
  function
• Organ-group of tissues that perform a similar
  function
• Organ System-group of organs that perform a
  similar function
• Organism-Organ systems working together to
  produce You!

3
11 Organ Systems In Human Body

• Nervous
• Integumentary
• Respiratory
• Digestive
• Excretory
• Skeletal
• Muscular

• 8. Circulatory
• 9. Endocrine
• 10. Reproductive
• 11. lymphatic

4
Types of Tissue (4)

• Muscle-most abundant, controls, internal movement
  (blood through circulatory system)
• Epithelial-cover surface of body line internal
  organs.(prevents blood leakage in heart)

5

• 3. Connective-hold organ is place binds
  different parts of the body together.
• 4. Nervous-receives info from external
  internal environments, analyzes the data,
  directs the response.

6
Maintaining Homeostasis

• Homeostasis-ability to maintain a controlled,
  stable internal environment
• Organ systems work together to do this
• Feedback inhibition- product of a system shuts
  down the system or limits its operation.
• Thermostat
• Rev limiter

7
35-2 The Nervous System

• Neurons have specialized projections called
  dendrites and axons. Dendrites bring information
  to the cell body and axons take information away
  from the cell body. Information from one neuron
  flows to another neuron across a synapse. The
  synapse is a small gap separating neurons.

8
Key terms

• Myelin sheath-insulated membrane that surrounds
  the axon
• Threshold-minimum level of stimulus that is
  required to activate a neuron.
• Neurotransmitter-chemicals used by a neuron to
  transmit an impulse across a synapse to another
  cell.

9
The Neuron
10
The Synapse
11
35-3 Divisions of the Nervous System

• Central Nervous System (CNS)
• Brain
• Spinal Cord
• Both are wrapped in 3 layers of connective tissue
  called meninges.
• Between 2 of the layers the space if filled with
  cerebrospinal fluid (acts a shock absorber)

12
The Brain
13

• Cerebrum-largest most prominent. Responsible
  for voluntary, or conscious, activities of the
  body.
• Cerebellum-2nd largest,back of skull, coordinates
  and balances the actions of the muscles.
• Brain Stem-Connects brain spinal cord.
• Pons and Medulla oblongata
• Thalamus Hypothalamus-btw brain stem
  cerebrum.
• Thalamus-receives relays messages from sense
  organs to proper region of the cerebrum
• Hypothalamus-Recognizes analyzes hunger,
  thirst, fatigue, anger, body Temp.

14
The Spinal Cord

• Main communication link between the brain and
  rest of body.
• Reflexes are processed directly here. (allows
  body to respond immediately to danger.)
• Protected by vertebrae

15
The Peripheral Nervous System

• Somatic Nervous System-Regulates activities under
  conscious control (muscle movement).
• Autonomic Nervous System- Regulates automatic
  activities (heartbeat, contraction of smooth
  muscle in digestive system)

16
35-4 The Senses

• Vision
• Hearing Balance
• Smell Taste
• Touch Related Senses

17
35-5 Drugs the Nervous System

• Stimulants-increases actions regulated by the
  Nervous System.
• Depressants-decrease the rate of functions
  regulated by the brain.
• Cocaine-causes sudden release in the brain of
  neurotransmitter called dopamine.
• Opiates-mimic endorphins, which help overcome
  pain.

18
Read This Section!!!!!!!!

• Marijuana-most widely abused illegal drug.
  Temporary feelings of euphoria disorientation
• Alcohol-Depressant, most dangerous abused,
  slows reflexes, disrupts coordination, impairs
  judgment.
• Fetal Alcohol Syndrome-heart defects, malformed
  faces, delayed growth, poor motor development.