Topic 5a: Homeostasis and Response: The Nervous System Flashcards
5a1
Define homeostasis
The maintenance of optimal internal conditions
What are 3 internal conditions that need regulation?
Blood glucose concentration
Body temp
Water levels (in the blood and tissue fluids)
Name the way that internal conditions are regulated
Automatic / involuntary control systems
What 3 main components work together to maintain a steady condition?
Receptors
Coordination centres
Effectors
Name an example of a coordination centre
Brain
Spinal cord
Pancreas
What are the effectors of the body
Muscles
Glands
What are responsible for maintaining a stable internal environment
Nervous system and hormones
What is the solution surrounding red blood cells when travelling thorough veins
Plasma
Define stimulus
A change in your environment that you might need to respond to
Give an example of a stimulus
Light, sound, touch, pressure, pain, chemical, or a change in position or temperature
Define a negative feedback mechanism
The mechanism that restores the optimum level
The mechanism that restores the optimum level is called the…
Negative feedback mechanism
What is the main risk of the negative feedback mechanism?
The effectors could just carry on producing the responses
Making the level change too much
What is the purpose of the nervous system?
Allows you to react to your surroundings
And allows you to coordinate your behaviour
Define a receptor
Cells that detect a stimuli aka a change in the environment
Define a coordination centre
They receive information from the receptors, process the info and instigate a response
Define an effector
Are muscles or glands which respond to nerve impulses and bring about a response to a stimulus
How do muscles respond to stimuli
They contract
How do glands respond to stimuli
Secrete chemical substances called hormones
State an example of a receptor
Taste receptors on the tongue
Sound receptors in the ears
Smell receptors in the nose
Light receptors in the eyes
Define a sensory neurone
The neurones that carry information
As electrical impulses
From the receptors
In the sense organs
To the central nervous system
Define a relay neurone
The neurones that carry electrical impulses
From sensory neurones
To motor neurones
They are found in the cns
Define a motor neurone
The neurones that carry electrical impulses
From the cns to the effectors
State the transmission of information to and from the cns (flow diagram)
Stimulus —> Receptors—> Sensory neurone —> Relay neurone (cns/coordinator) —> Motor neurone —> Effector —> Response
Define a synapse
The connection between two neurones
How are nerve signals transferred across synapses?
The signal is transferred by chemicals which diffuse across the gap
These chemicals set off a new electrical signal in the next neurone
Define a reflex
Fast automatic responses to certain stimuli
Give an example of a reflex
Pupil contraction when confronted with light
Adrenaline when confronted with shock
Knee jerk reflex
Describe the reflex of pupil contraction
If someone shines a bright light in your eyes
Your pupils automatically get smaller
So that less light gets into your eyes
Which stops them from getting damaged
Define a neurone
Nerve cell
Adapted to carry electrical impulses from one place to another
What is a nerve cell called
Neurone
What is the name for a bundle of neurones?
Nerve
Define a nerve
Bundle of neurones
Blood supply to provide oxygen and glucose
