Central nervous system

Question 1

Central nervous system

Answer 1

Processes electrical impulses from nerves. Is made up of the spine and brain. It interprets the impulse and initiates a response.

Question 2

Reflex arc

Answer 2

Starts by a change to environment detected by a stimulus (e.g. touch a hot surface). Sensory receptors on the skin notice the change. An impulse/action potential is taken along the sensory neurone to the relay neurone. This then carries the impulse to the central nervous system. The message doesn’t go to the brain yet to save time (involuntary/automatic response). The spine initiates a response and the relay neurone carries the response out of the CNS to the motor neurone. This then reaches an effector muscle or gland where a response takes place.

Question 3

PNS

Answer 3

Peripheral nervous system. Includes the nervous. The other part that makes up the nervous system with the CNS.

Question 4

ANS

Answer 4

Automatic nervous system. Involuntary nervous system that controls things like increasing your heart rate when you exercise.

Question 5

Motor neurone

Answer 5

Carries the response from the relay neurone to the effector gland or muscle. The signal is picked up the by the dendrite and moves into the cell body. The nucleus processes the message. The action potential then moves along the axon. Some motor neurones are myelinated to protect and so the action potential can move quickly (e.g. spine). The action potential can jump between Schwann cells in the nodes of Ranvier. This is much quicker. The synaptic bulbs are attached to an effector muscle or gland causing a response.

Question 6

Synapse

Answer 6

A junction between two neurones or neurone and effector.

Question 7

Synapse process

Answer 7

An impulse reaches the pre-synaptic membrane and neurone end. Neurotransmitters are contained in vesicles and move forward to the edge. Calcium channels open causing an influx of calcium ions into the presynaptic neurone. Neurotransmitters are then released by exocytosis into the synaptic cleft. They bind to the receptors on the post synaptic membrane and the message is processed leading to an action potential. Lots of mitochondria are in the presynaptic membrane to make ATP for this process. Neurotransmitters are actively pumped back into the axon.

Question 8

Acetylcholine

Answer 8

It is the chief neurotransmitter of the parasympathetic nervous system, the part of the autonomic nervous system (a branch of the peripheral nervous system) that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.