10 Biology - Coordination and Response
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Identify the components of the central nervous system (CNS)
brain and spinal chord
Identify the components of the peripheral nervous system (PNS)
motor and sensory neurons
What is the job of the nerve cells/neurones?
they carry electrical impulses from one place to another
Describe/label the structure of a neurone
http://www.bbc.co.uk/staticarchive/5d3d66ef622165ae607b3c02f6e603c524eececf.gif
What are receptors?
detect stimulus and creates an electrical signal in response
What are effectors?
Effectors are parts of the body - such as muscles and glands - that produce a response to a detected stimulus
Examples of effectors
• a muscle contracting to move an arm • muscle squeezing saliva from the salivary gland • a gland releasing a hormone into the blood
Summarise how information flows from receptors to effectors in the nervous system
http://a.files.bbci.co.uk/bam/live/content/zwqy4wx/small
What are reflex actions?
a way for the body to automatically and rapidly respond to a stimulus to minimise any further damage to the body, it follows general sequence and does not involve the brain
Describe the sequence of a reflex action
• Receptor in the skin detects a stimulus (the change in temperature). • Sensory neurone sends impulses to relay neurone. • Motor neurone sends impulses to effector. • Effector produces a response (muscle contracts to move hand away).
What is a reflex arc? give an example
The nerve pathway followed by a reflex action eg. when you touch something to hot & move quickly away
What are antagonistic pairs?
Muscles work in antagonistic pairs. This ensures that when a part of the body is moved, it can move back to its original position
Give examples of antagonistic pairs
the biceps and triceps in the arm the quadriceps and hamstrings in the leg
What is a synapse?
It is a gap where two neurones meet Allows impulse to go from one to another Regulate electrical impulse
What is the eye?
It is a sense organ that responds to light
Label and describe the function of each of the structures in the eye
http://a.files.bbci.co.uk/bam/live/content/z2xgd2p/large
What is the retina?
Where light passes through the eyeball
What is the light that enters the eye controlled by?
A reflex action
How does the eye change when going from dark to bright light and then back to dark? What type of response is this?
The iris controls the amount of light that enters the eye by changing the size of the pupil This a reflex action
Describe what happens when you are looking at an object far away then focus on an object close to you
FAR CLOSE Refraction of light is -less -more Ciliary muscles -relax -contract Ligaments -stretch -relax Lens become -tall & thin -short & fat
Describe the differences between each type of neurone relay, sensory, motor
• In motor neurone body is at the end, in relay & sensory it is in the middle • Only motor has nodes of ranvier • Relay doesn’t have myelin sheath • Motor connected to muscle
If you put your hand on something hot you will react. Describe this in terms of a reflex arc
• Receptor receives a stimulus & converts it into an electrical impulse • Sensory neurone carries it to CNS, signal passes via a synapse (gap, regulates nervous impulse) to relay • Relay neurone carries it slowly across spine • Motor neurone carries impulse from CNS to reflector • Effector carries out an action(response) to deal with stimulus
Why don’t relay neurones have a myelin sheath?
Myelin sheath allows messages to be sent faster, if the relay neurones don’t have it allows the action to be modified as it if slower
What is a hormone & what is its function?
Hormones are chemical substances (made of proteins) that help to regulate processes in the body They are secreted by glands & travel to target organs in the bloodstream