Homeostasis And Response Flashcards
What is homeostasis
Regulation of the conditions inside your body to maintain a stable internal environment
Main control systems in the body
Nervous system
Hormonal system
All automatic control systems are made up of whet 3 things
Receptors , coordination centres and effectors
What is the central nervous system
Animals with backbones
Brain and the spinal chord
Connected to the body by sensory neurones
And motor neurones
What are the sensory neurones
Neurones that carry information as electrical impulses from receptors to CNS
What are motor neurones
Neurones that carry electrical impulses from CNS to effectors
What are effectors
All your muscles and glands which respond to nervous impulses
What’s are receptors
Cells that detect stimuli
What do effectors do
They respond to nervous impulses and bring about change
What is a synapse
Connection between two neurones is called a synapse
Nerve signals are transferred by chemicals which diffuse across the gap
These set off a new electrical signal
What are reflexes and what do they do
Rapid , automatic responses to certain stimuli that don’t involve the conscious part of the brain
Reduce chances of getting injured
The passage of information in a reflex is called a reflex arc
How does a reflex arc work
Neurones of the reflex arc go through the spinal chord OR through unconscious part of the brain
When the stimuli is detected by receptors the impulses are sent along the sensory neurone to relay neurone
When the impulses reach the synapses , chemicals are released
Impulses then move to effector
Leading to muscle contraction
Investigating reaction time practical
Person should sit down at a table with aim resting on the edge
Hold a ruler vertically between their thumb and finger then let go without giving a warning
The person being tested should try catch the ruler as quickly as possible
Reaction time is measured by the number on the ruler where it is caught the further down the owner the slower the reaction time
Repeat and calculate the mean reaction time
The person being tested should the drink a caffeinated drink
After 10 minutes repeat the investigation
Control variables are : same person , same hand , drop ruler from same height
What are hormones
Hormones are chemical molecules released directly into the blood. They are carried in the blood to other parts of the body, but only affect particular cells in particular organs
What is the pituitary gland
Produces many hormones that regulate body conditions
Called the master gland
Act on glands directing them to release hormones
