topic 5 pg 65 - 69 Flashcards
homeostasis and responses
what is homeostasis?
-the regulation of the conditions inside your body (and cells)
- To maintain a stable internal environment in response to changes in external and internal conditions
why does the conditions inside your body need to be kept steady?
to allow cells and enzymes in your body to function properly
what is a stimulus?
A change in the environment
what regulates your internal environment?
Automatic Control Systems (ACS)
what is the Automatic Control System ?(2 things)
- controls internal environment
- nervous and hormonal communication system
what do the nervous and hormonal communication system do? (3 things)
-they control body temperature
- blood glucose level
- water content
what is the Automatic Control System made up of (3 things)?
1)-receptors
2)- coordination centres (brain, spinal cord, pancreas)
3)- effectors
what is negative feedback (ACS)?
-when the level of something (e.g. water or temperature) gets too low or too high
[> the negative feedback brings it back to normal
how does the negative feedback work when the level of something is too HIGH?
1)-Receptors detects a stimulus - level is too high
2)- The coordination centre receives and processes the information, then organises a response
3)- Effector produces a response, which counteracts the change and restores the optimum level - the level decreases
how does the negative feedback work when the level of something is too LOW?
1)-Receptors detect a stimulus - level is too low
2)-The coordination centre receives and processes the information, then organises a response
3)-Effector produces a response, which counteracts the change and restores the optimum level - the level increases
The Nervous System means that humans can ……
react to their surroundings and coordinate their behaviour
Name the parts which make up the Nervous System? ( 4 things)
1)- Central Nervous System (CNS)
2)- Sensory Neurones
3)-Motor Neurones
4)-Effectors
what is the Central Nervous System (CNS)?
-it is the brain and spinal cord (only found in mammals)
- is connected to the body by sensory neurones and motor neurones
what are Sensory Neurones?
neurones that carry information as electrical impulses FROM the receptors TO the CNS
what are Motor Neurones?
neurones that carry electical impulses From the CNS TO effectrors
what are Effectors?
all your muscle and glands, which respond to nervous impulses
what does the CNS do with the information it receives?
CNS receives information then coordinates a response (decides what to do about it)
what is the connection between 2 neurones called?
Synapse
how are nerve signals transferred?
by chemicals which diffuse
what are reflexes?
-help avoid getting injured
-rapid, automatic responses to certain stimuli (doesn’t involve the conscious part of the brain)
how does a reflex work?(6 stages)
1)- Neurones in reflex arc go through spinal cord
2)-when a stimulus is detected by a receptor, impulses are sent along a sensory neurone to a relay neurone
3)-when the impulses reach a synapse between the sensory and relay neurone, they trigger a chemical to be released , these chemicals cause impulses to be sent along the relay neurone
4)-when the impulses reach a synapse between the sensory and relay neurone and a motor neurone a chemicals are released and causes impulses to be sent along the motor neurone
5)- the impulses travel along the motor neurone to the effector (a muscle)
6)- the muscle then contracts
what is reaction time?
the time taken to respond to a stimulus
what effects the reaction time?
-age
-gender
-drugs
how to measure reaction time? PRACTICAL (2 things)
-dropping ruler experiment
or
-computer experiment
