Nervous system Flashcards
Nervous system
Body system that includes brain, spinal cord and nerves
Central nervous system (CNS)
Part of the nervous system made up of the brain and spinal cord
Doesn’t include nerves or neurones
Peripheral nervous system
Made up of neurones and nerves
Where is the spinal cord?
In the back of the neck
Receptors
Cells that detect a stimulus
Stimuli
Changes in the environment such as light, heat, sound, gravity, smell, taste, or temp
Where are the electrical impulses picked up by receptor cells sent down by?
Neurones aka nerve cells
Where do nerve cells send the electrical impulse to?
Central nervous system
What does the central nervous system do after receiving the impulse?
Sends more electrical impulses to effector cells
Effectors
Muscles/ glands that cause a response to change in stimuli
NOT nerves or neurones
Examples of what an effector could be
Muscle that moves after being burnt
Gland that secretes a hormone
Reflex arc
System how the body reacts on impulse to protect itself from being hurt
Without connection to conscious part of the brain
What makes a reflex arc different?
No connection to conscious part of brain thus decision made without thinking, therefore it’s very rapid
This is called an impulse
Beginning of a reflex arc if you burnt your finger?
Stimulus (burn) detected by receptors in the skin
In a reflex arc, what do the receptors do after detecting a stimulus?
Send electrical impulses down a sensory neurone that it’s connected to
What is at the end of a sensory neurone?
A synapse, connected to CNS
What do the first synapses do in a reflex arc?
Send a chemical, diffusing through to a relay neurone in the CNS
What does the relay neurone do in a reflex arc?
Releases another chemical, causing electrical impulse across from relay neurone to motor neurone
What does the motor neurone do after receiving electrical impulse?
Passes the electrical impulse down an effector
If the effector is a muscle in a reflex arc, after your hand is burnt, what will it do?
Contract and move the hand away from the burn to protect itself
What does the brain contain?
Millions of Interconnected neurones
Cerebral cortex
Part of the brain controlling language, memory and consciousness
Cerebellum
Part of the brain controlling balance and coordinates movements
Medulla
Controls heart rate and breathing rate
What area of the brain is the cerebral cortex located?
Large, folded outer part
Which part of the brain is the cerebellum located?
Bellow the cerebral cortex, the smaller ball looking part
Which part is the medulla located?
The smallest stub part
Why is the brain difficult to study or treat illnesses inside?
Brain protected by skull, so difficult to access
Structures of the brain very complex, difficult to work out which parts control what
Very delicate and easy to damage
3 ways scientists study the brain
-Study someone with brain damage to correlate where the damage is to what it effects
-Electrically stimulate parts of the brain and see change in behaviour
-MRI scanning to see what parts are active during various activities
Normal nervous system response summary
stimulus —> receptor —> coordinator (brain) —>effector (muscle/gland) —>response
Reflex arc summary
Receptor —> sensory neurone —> Synapse —> chemicals diffused —> motor neurone —> effector —> response
