Responding To Change - Unit 2 Flashcards
What does homeostasis mean?
keeping the body’s internal environment consistant
What is osmoregulation?
Regulating water content
What is thermoregulation?
Regulating body temperature
What is blood glucose regulation?
Regulating blood glucose
What is negative feedback?
When something changes in the environment it trigger a response that counteracts the change - e.g a rise in body temp causes a response that lowers body temp.
When wont negative feedback work?
When the environment changes too much
What part of the body controls body temperature?
The Hypothalamus (part of your brain)
What happens when you are too hot
Erector hair muscles relax, so hairs lie flat Lots of sweat is produced because it cools you down when it evaporates Blood vessels close to the skin dilate (widen) (vasodilation) it allows more blood to flow near the surface so it can transfer more heat into the surroundings.
What happens when you are too cold
Erector muscles contract, hairs stand on end Very little sweat is produced Vasoconstriction. Blood vessels near the skin constrict so less heat is transferred to the surroundings
What is a hormone?
Chemical messages sent in the blood
What are the two ways signals can be sent in your body?
Using hormones or nerves
What do hormones travel in
Blood
What are the cells and organs called that hormones affect?
Target cells Target organs
What kind of effect does a hormone have
A long lasting effect
How do neutrons send signals
The transmit an electrical impulse
What is the branched ending of a nerve called
Dendron
Why do dendrites have branched endings
To connect with lots of other neurones
What part of the cell is the electrical impulse passed along
The axon
What does a myelin sheath do
It acts as an electrical insulator which stop the impulse getting lost
What is the connection between neurones called?
A synapse
What chemicals transmit the nerve impulse
Neurotransmitters
What are the differences between hormones and nerves?
Nerves: Very fast message Act for a very short time Act on a very precise area Electrical message Hormones: Slower message Act for a long time Act in a more general area Chemical message
What is a stimulus
A change in your environment
What are the 5 sense organs
Eyes Ears Nose Tongue Skin
What are receptors
A group of cells which are sensitive to a stimulus. They change stimulus energy into electrical impulses
What receptors does each of the sense organs have
Eyes - light receptors
Ears - sound and balance receptors
Nose - smell receptors
Tongue - taste receptors
Skin - pressure and heat receptors
What parts of the body are in the central nervous system
Brain spinal cord
What does the central nervous system do
Coordinates the response to the stimulus