Nerves Flashcards
Define homeostasis
The ability to change internal conditions to adapt to the animal’s surroundings
Which two organ systems allow the body to perform homeostasis
the nervous system and the endocrine system
How do plants change according to their surroundings
via phototropism, e.g. reacting to the direction of light and growing towards it
What is a stimulus
change in the animal’s surroundings
What is a receptor
the organ which detects the change
What is an effector
muscles which react to the stimulus
What do receptors do
They detect the stimulus and change the energy into nerve impulses e.g. the eye converts light energy to nerve impulses
Name the two nervous systems and what they consist of
Central Nervous System, consisting of the brain and the spinal cord and the Peripheral Nervous System, consisting of every other nerve in the body
Name the three types of neurones
Sensory, Motor, Relay
What is a dendrite
Tree-like projections which connect to different neurones. One neurone can connect to many other neurones
What is the axon
The long section connecting the dendrites together with other nerves and muscles. It can be around 1m long
What is the myelin sheath and what is it used for
Cells wrapped around the axon, insulates the axon and speeds up the transmission of the impulse.
What is a reflex
They are automated actions which do not involve the brain
Describe the steps of the reflex arc, from when the stimulus is detected to when the muscle reacts
The receptors detect the stimulus change in temperature and send an impulse along the sensory neurone. The sensory neurone passes the impulse across the spinal cord to a relay neurone The gap between neurones is called a synapse. The relay neurone then passes the impulse to motor neurone The motor neurone causes the effector to contract and move the arm away from the stimulus
