B3.1 The Nervous system - Structure & Function Flashcards
<p>What is the function of the nervous system?</p>
<p>To detect changes in the environment and respond to these changes to maintain homeostasis.</p>
<p>State the name given to a change in environment</p>
<p>Stimulus</p>
<p>Name the group of cells responsible for detecting a stimulus?</p>
<p>Sensory receptors</p>
<p>Where are receptor cells generally found?</p>
<p>Sense organs</p>
<p>Listsome common examples of sense organs an their stimulus.</p>
<ul> <li>Eye - Light</li> <li>Tongue -Chemical tastes (in food and drink)</li> <li>Nose -Chemical smells (in the air)</li> <li>Skin -Temperature, pressure and pain</li> <li>Ears - Sound</li></ul>
<p>What is the name given to the cells that carry out the response?</p>
<p>Effectors</p>
<p>State the two types of effectors giving an example response for each.</p>
<ol> <li>Muscles - respond by contracting</li> <li>Glands - respond by secretions</li></ol>
<p>State the two key components of the nervous system.</p>
<ul> <li>Central nervous system (CNS)</li> <li>Peripheral nervous system (PNS)</li></ul>
<p>State the key components of the nervous system.</p>
<ul> <li>Brain</li> <li>Spinal cord</li> <li>Nerves</li></ul>
<p>Define the central nervous system.</p>
<ul> <li>The CNS is composed of the brain and spinal cord</li> <li>The brain is only involved in voluntary actions</li> <li>The spinal cord is invovled in both voluntart and involuntary actions</li></ul>
<p>Define the peripheral nervous system.</p>
<ul> <li>The PNS is composed of the nerve cells that carry information to and from the CNS</li> <li>The spinal cord is invovled in both voluntart and involuntary actions</li></ul>
<p>List the three main types of nerve cell including their pathway.</p>
<ol> <li>Sensory – The neurones that carry information as electrical impluses from the receptors in the sense organs to the CNS</li> <li>Relay – The neurones that carry electrical impulses from sensory neurones to motor neurones. They are found in the CNS.</li> <li>Motor – The neurones that carry electrical impulses from the CNS to the effectors</li></ol>
<p>What is meant by the direction of impulse?</p>
<ul> <li>The direction in which a signal travels through a nerve</li></ul>
<p>What type of signal is transmited by the nervous system?</p>
<p>Electrical</p>
<p>State the difference between a nerve and a neurone.</p>
<ul> <li> <p>Neurones are specialized cells that conduct electrical impulses through the body.</p> </li> <li> <p>A nerve is a bundle of many nerve fibres enclosed within a protective sheath.</p> </li> <li> <p>Nerve fibres are the long axons of neurones together with any associated tissues.</p> </li></ul>
<p>Write out a pathway for a 'voluntary action'.</p>
<p>Stimulus→ Receptor cells→ Sensory neurone→ Spinal cord→ Brain→Spinal cord→ Motor neurone→ Effector→ Response</p>
<p>What is menat by a '<em>coordinated</em>' response?</p>
<p>The ability of the brain to process information from many sensory receptors simultaneously and send a series impulses to different parts of the body to produce the required actions.</p>
<p>State the direction of impulse through the neurone with reference tolabels.</p>
<p>Impulse travels from the dendrites through neurone to axon terminals</p>
<p>Name and label the neurone</p>
<p>Motor neurone</p>
<ol> <li>Dendrites</li> <li>Cell body</li> <li>Axon</li> <li>Axon terminals</li></ol>
<p>Name the cell type that surrounds the axon of certain neurones and their purpose.</p>
<ul> <li>Cell type - Schwann's cells</li> <li>Collectively they form the myelin sheath</li> <li>The myelin sheath insulates the axon and increase the speed of transmission</li> <li>Gaps between these cells = nodes of Ranvier</li></ul>
<p>Where would you expect to find a synapse?</p>
<p>Between the axon terminals of the pre-synaptic neurone, and the dendrites of the post-synaptic neurone.</p>
<p>What is another term given to the gap between the axon terminals of the pre-synaptic neuroneand the dendrites of the post-synaptic neurone.</p>
<p>Synaptic cleft.</p>
<p>Name to mode of transmission within a synaptic cleft.</p>
<p>Chemical.</p>
<p>Explain the pathway of transmision fromaxon terminals pre-synaptic neuroneto post-synaptic neurone.</p>
<ol> <li>Electrical signal arrives ataxon terminals of the pre-synaptic neurone.</li> <li>Vesicles containing neurotransmitters stimulated.</li> <li>Neurotransmitters difuse out ofpre-synaptic neurone into synaptic cleft.</li> <li>Neurotransmitters difuse acrosssynaptic cleft.</li> <li>Neurotransmitters difuse into dendrites of the post-synaptic neurone</li> <li>Electrical signal triggered by neurotransmitters in the post-synaptic neurone</li></ol>
<p>e.g electrical→ chemical→ electrical</p>
Which organelle would you expect in abundance in the neurones?
Mitochondria to provide energy.
Describe the difference in a voluntary and reflex action.
- Voluntary actions involve conscious thought
- Reflex actions are automatic (involuntary) reactions, they are unconscious missing out the brain, occuring without thinking.
State the reflex that protects the retina in changing light intensities
Pupil reflex
Explain how your body responds to stepping on a sharp stone from stimulus to response.
- Stimulus - stepping on stone
- Receptor - pressure receptors in the skin
- Electrical impulse transmitted through sensory neurone to spinal cord
- Electrical impulse transmitted through motor neurone to muscles in thigh of the leg.
- Effector - the muscles in thigh of the leg lift the leg to move away from the object in response.
