7th Grade

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7th Grade Unit 5 The Structure and Function of
Body Systems Lesson 2 Nervous, Digestive, and
Excretory Systems Vocabulary of Instruction
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Absorption

• The uptake of water or dissolved chemicals by a
  cell or an organism (as tree roots absorb
  dissolved nutrients from the soil).

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Autonomic Nervous System

• Part of the nervous system which controls
  involuntary bodily functions.

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Central Nervous System

• Portion of the nervous system which consists of
  the brain and spinal cord.

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Chemical Digestion

• Involves enzymes that break down starches,
  proteins, fats, etc. in the small intestine.
• Each type of molecule is broken down into its
  simplest part through the use of enzymes.

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Excretion

• Is the process of eliminating waste products of
  metabolism and other non-useful materials.

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Involuntary Muscles

• Muscles whose activity is not subject to
  conscious control.

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Kidney

• Are two bean shaped organs that filters wastes
  (such as urea) from the blood and 
• excrete them, along with water, as urine.

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Mechanical Digestion

• Requires the use of energy and the mechanical
  breaking down of food via chewing.

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Motor Neurons

• Applies to neurons located in the central nervous
  system (CNS) that project their axons outside the
  CNS and directly or indirectly control muscles.

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Neurons

• Nerve cell, which is the basic functional unit of
  the nervous system.

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Peripheral Nervous System

• Resides or extends outside the central nervous
  system (the brain and spinal cord) to serve the
  limbs and organs. Unlike the central nervous
  system, however, the Peripheral Nervous System
  (PNS), it is not protected by bone, leaving it
  exposed to toxins and mechanical injuries.

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Peristalsis

• Involuntary waves of muscle contraction that keep
  the food moving along in one direction through
  the digestive system.

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Sensory Neurons

• Are nerve cells within the nervous
  system responsible for converting external
  stimuli from the organism's environment into
  internal electrical motor reflex loops and
  several forms of involuntary behavior, including
  pain avoidance.

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Somatic Nervous System

• Is part of the peripheral nervous
  system associated with the voluntary control of
  body movements through the action of skeletal
  muscles, and with reception of external stimuli,
  which helps keep the body in touch with its
  surroundings.
• Examples
• Touch
• Hearing 
• Sight

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Toxins

• Are poisonous substances produced by living cells
  of organisms.

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Voluntary Muscles

• Drawn muscles muscles whose activities can be
  controlled by the brain (e.g. skeletal muscles).