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Nerves and the nervous system


What are we learning?


Why are we learning this?



dendrite, cell body, axon, myelin sheath, axon terminal, neurotransmitter


Nerve cells (neurons) allow cells to communicate with each other.

Nerves are one way that organisms can detect and respond to stimuli

This helps cells or organisms to maintain homeostasis

How big are they?


Most cells are small – microscopic. But not all! – “The longest cell in Andy Farke is one of the primary afferent (sensory) neurons responsible for sensing vibration or fine touch, which runs from the tip of his big toe to his brainstem. “

longest-cell-in-andy-farke primary afferent sensory neuron

Image from svpow.com/2015/06/12/the-longest-cell-in-andy-farke/

How do they work?

Neurons may stimulate other nerve cells, or muscle cells

When nerves stimulate muscles they cause the muscle to contract and produce movement.


How does one nerve send a signal to another nerve? (snapse)



Sample questions

Feb Biology MCAS 2016

The axons of some vertebrate neurons are wrapped with special cells called Schwann cells, as shown below.

Schwann cells in nerves

Which type of signal jumps from node to node between the Schwann cells to move down the axon?

A. a digital pulse            B. a magnetic pulse
C. an electrical signal    D. a glycoprotein signal


Base your answers to questions 35 through 37 on the diagram below
and on your knowledge of biology.

Nerve cell neurotransitter

from Edusolution.com, Livinenviron, June2004

35. The process represented in the diagram best illustrates

(1) cellular communication
(2) muscle contraction
(3) extraction of energy from nutrients
(4) waste disposal

36. Which statement best describes the diagram?

(1) Nerve cell X is releasing receptor molecules.
(2) Nerve cell Y is signaling nerve cell X.
(3) Nerve cell X is attaching to nerve cell Y.
(4) Nerve cell Y contains receptor molecules for substance A.

37. A drug is developed that, due to its molecular shape, blocks the action of substance A. Which shape would the drug molecule most likely resemble?

neurotransmitter shapes


Base your answers to questions 56 through 58 on the diagram below.

Nerves synapse muscle Q&A

From Edusolution.com, Livinenviron, June 2002

56 In region F, there is a space between nerve cells C and D.
Cell D is usually stimulated to respond by:

(1) a chemical produced by cell C moving to cell D
(2) the movement of a virus from cell C to cell D
(3) the flow of blood out of cell C to cell D
(4) the movement of material through a blood vessel that forms between cell C and cell D

57 If a stimulus is received by the cells at A, the cells at E will most likely use energy obtained from a reaction between

(1) fats and enzymes     (3) glucose and oxygen
(2) ATP and pathogens  (4) water and carbon dioxide

58 State one possible cause for the failure of muscle E to respond to a stimulus at A.


Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-LS1-2. Develop and use a model to illustrate the key functions of animal body systems: Emphasis is on the primary function of the following body systems (and structures): digestive (mouth, stomach, small intestine [villi], large intestine, pancreas), respiratory (lungs, alveoli, diaphragm), circulatory (heart, veins, arteries, capillaries), excretory (kidneys, liver, skin), and nervous (neurons, brain, spinal cord).

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