The Human Body

1
The Human Body
2
Life Processes

• Regulation
• Nutrition
• Transport
• Respiration
• Locomotion
• Excretion

3
Organ Systems

• Because humans are complex multicellular
  organisms, organ systems are needed to carry out
  the major life processes.
• Levels of organization
• cells?tissues?organs?systems

4
Regulation

• The nervous and endocrine systems control and
  coordinate life activities to maintain
  homeostasis.
• This is known as regulation.

5
Nervous System
6
Nervous System

• Neurons specialized cells that transmit
  electrochemical messages called impulses.
• This is how the body communicates rapidly
  producing responses of short duration.

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A Neuron
Neuron
Section 35-2
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Neuron

• Active transport maintains nerve cells in a
  charged state ready to transmit a message.
• Nerve cells use lots of glucose and have lots of
  mitochondria.

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Active Transport
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Synapse

• Neurons communicate with each other by secreting
  chemicals across a tiny gap called the synapse.

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Figure 35-8 The Synapse
Synapse
Section 35-2
Direction of Impulse
Dendrite of adjacent neuron
Axon
Receptor
Vesicle
Axon terminal
Synaptic cleft
Neurotransmitter
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Commonly Abused Drugs
Drugs Affect the Synapse
Section 35-5
Used to increase alertness, relieve
fatigue Used to relieve anxiety, irritability,
tension Used to relieve pain
Stimulants Depressants Opiates
Amphetamines Barbiturates Tranquilizers M
orphine Codeine
Increase heart and respiratory rates elevate
blood pressure dilate pupils decrease
appetite Slow down the actions of the central
nervous system small amounts cause calmness and
relaxation larger amounts cause slurred speech
and impaired judgement Act as a depressant
cause drowsiness, restlessness, nausea
Drug Type
Medical Use
Examples
Effects on the body
13
Nervous System

• Central Nervous System
• Brain spinal cord
• Peripheral Nervous System
• Nerve branches off the brain and spinal cord
• Sense organs

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Figure 35-9 The Brain
Brain
Section 35-3
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Cross Section of the Spinal Cord
Spinal Cord
Section 35-3
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The Senses of Smell and Taste
Sense Organs
Section 35-4
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Figure 35-14 The Eye
Eye
Section 35-4
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Figure 35-15 The Ear
Ear
Section 35-4