Flashcards in Nerves and hormones Deck (14):
What do the brain and spinal cord form?
Central nervous system (CNS)
What do nerves contain?
What do sensory Neurons carry
Carry impulses form receptors to the CNS
What do motor Neurons carry,
Carry impulses from the CNS to effector organs- these could be muscles or glands
Muscles respond by...
Glands respond by...
Muscles respond by contracting.
Glands respond by secreting (releasing) chemicals.
Nervous system in order...
Receptor to effector
Receptor, sensory Neuron, CNS, motor Neuron, effector
Main steps in a reflex action
-a receptor defects a stimulus.
-a sensory Neuron transmits the impulse to the CNS.
-a relay Neuron passes the impulse on.
-a motor Neuron is stimulated.
-the impulse passes to an effector (muscle or gland)
-action is taken (the response)
What is the junction between the two neurons?
What happens when an impulse arrives at the synapse?
Chemicals are released that cross the gap, chemical transmitter released, activates receptors on neurone, causes electrical impulse to be generated, chemical transmitter destroyed.
Reflex action, stimulus-response
Stimulus (hot plate), receptor(pain in right finger), sensory neurone, relay neurone (in spinal cord), motor neurone, effector (muscles in hand), response (withdraw hand)
What is a reflex action, what does a reflex action miss out?
Reflex action speeds up the response time by missing out the brain completely.
SPINAL CORDS ACTS AS COORDINATOR, PASSES IMPULSE DIRECTLY FROM SENSORY NEURONE TO A MOTOR NEURONE VIA A RELAY NEURONE. BY-PASSES THE ORAIN
Positive of a reflex action
Automatic and quick
We have to control conditions in our body like body temperature. What do we control this by?