Coordination And Response Flashcards
What is part of the CNS?
Spinal cord and brain (linked by sensory neurones)
What three things are required for a response?
Stimulus, effector, receptor
Define homeostasis
The maintenance of a constant internal environment
Describe Homeostasis when too hot
Lots of sweat produced (for evaporation)
VASODILATION- blood capillaries widen to transfer more heat energy to surroundings
Hair lies flat
Describe homeostasis when you’re too cold
Little sweat is produced
VASOCONSTRICTION- minimise heat loss
Shivering increase rate of respiration
Hair stand on end to trap air and form an insulating layer
What are neurotransmitters
At the synapse chemicals (called neurotransmitters) diffuse across the gap
They continue the message by setting off a new electrical signal in the next neurone
What happens when you touch a hot object
The receptors detect the stimulus, sending impulses to the CNS
The sensory neurone in the CNS passes the message to the relay neurone
Relay neurones relay the message to the motor neurones, then the effector
The muscle contracts, making the response
What happens to the eye when do using on distant objects?
The ciliary muscles relax, suspensory ligaments pull tight.
Lens goes thin (less curved)
Refracts light by a smaller amount
What happens to the eye when focusing on a near object?
Ciliary muscles contract, slackens suspensory ligaments
Lens becomes fat (more curved)
Increases amount of light refracted
Purpose of adrenaline
Readies for flight or fight
Increases heart rate, blood flow and blood sugar levels
Purpose of insulin
Controls blood sugar levels
Purpose of testosterone
Promotes male secondary sexual characteristic (facial hair etc)
Purpose of progesterone
Maintains lining of uterus
Oestrogen
Controls menstrual cycle, female secondary sexual characteristics (eg widening hips etc)
