4.5 Homeostasis and NS structure and function Flashcards
Homeostasis is…
The maintenance of a constant internal environment
Name 4 internal conditions that need to be controlled?
water and ions
temperature
glucose
waste
What 2 control systems do we have in our body to regulate your internal environment?
nervous and hormonal
Your control systems have what 3 main components which work together to maintain a steady condition. Name them
- receptors
- coordination centres - brain/spinal cord/pancreas
- effectors
what are receptors?
special cells that detect stimuli and then send an electrical message along the sensory neurone to the CNS
Stimuli are..
changes in the environment (that are detected by receptors)
An effector is..
a muscle or gland that brings about a response
Where do sensory neurones carry electrical impulses from and to?
From receptors to the CNS
Where do motor neurones carry electrical impulses from and to?
From the CNS to the effector (muscle or gland)
What is a relay neurone?
A short neurone that carries an electrical impulse around the CNS in a reflex action
Where do you find a synapse?
The small gap between the axon of one nerve and the dendrites of another
Which type of chemical moves across a synapse
Neurotransmitter
What is a reflex response
an automatic response that you do not have to think about (involuntary)
How many neurones make up an reflex arc?
Three
Why are reflex actions beneficial?
Prevent us from harm. Do not have to be learned.
Name 4 stimuli that can be detected by receptors in the skin
Touch, pressure, temp, pain
How do neurotransmitters travel across a synapse
by diffusion
What comes next?
stimulus –> receptor–> ?
Sensory neurone
What comes next?
CNS (co-ordinator)—> motor neurone —> ?
Effector
Where can receptors be found? (5)
Eyes, ears, tongue, nose, skin
