Life science Flashcards
(66 cards)
What is the two main parts of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
What does the CNS consist of?
Brain and spinal cord
What does the PNS consist of?
sensory receptors and nerves
What is the main function of the CNS?
CNS: Examines the information received, and then sends out messages to tell different parts of the body what they should do.
What is the main function of the PNS?
PNS: Continuously inform the CNS of changing conditions and transmit the decisions made by the CNS back to effector organs.
What are neurons?
Neurons: Specialised cells that transmit and receive messages in the form of an action potential (electrical impulses).
What is the axon?
Axon: Is a single, tube like, extension that transmits neural information away from cell body through axon terminals and terminal buttons to other neurons or cells.
What are dendrites?
Dendrites: Small threads arranged around the cell body. Dendrites are the part of a neuron that receives input information from other cells.
What is the myelin sheath?
Myelin Sheath: White, fatty substance covering the axon. The myelin sheath is an insulating layer, which allows electrical impulses to transmit quickly and efficiently along the nerve cells.
What is the axon terminal?
Axon Terminal: are the small branches at the end of an axon. Each axon terminal has a small knob like swelling at its tip called terminal button.
What is the axon terminal button?
Axon Terminal Button: is the button-like endings of axon terminals where the message is passed from this neuron to other neurons or the effector organ.
How is a neuron similar to other cells?
Neurons have a nucleus, cytoplasm and cell membrane.
What are the different neurons?
Sensory Neuron, Interneuron, Motor Neuron
What does the Sensory Neuron do?
Sensory Neuron: receives stimuli information from sensory receptors and carries information as an impulse to CNS.
What does the interneuron do?
Interneuron: enables communication between sensory or motor neurons and the CNS
What does the motor neuron do?
- Motor Neuron: carries impulses from CNS to the effectors.
What is the stimuli in taste buds on the toungue?
taste buds on the tongue detects chemical stimuli in the mouth
What is the stimuli in retina cells in the eyes?
retina cells in the eye detect light/visual stimuli
What is the stimuli in cochlear cells in the ear?
cochlear cells in the ear detect sound waves/auditory stimuli
What is the stimuli in thermoreceptors?
thermoreceptors detect heat/temperature stimuli
What is the function of a neurotransmitter?
Neurotransmitters are a chemical messenger, which carry the signal over the synapse between neurons.
What is a synapse?
Small gap between neurons
How are messages transmitted between neurons?
When the electrical impulse reaches the axon terminals, the neurotransmitters are released into the synapse. The neurotransmitters quickly cross the synapse and bind to receptors on the dendrite of the next neuron. This binding of the neurotransmitter to the receptor on the dendrite triggers the neuron to transmit the message as an electrical impulse along its length.
What are disadvantages of the synapse?
They slow the passage of a message along a nerve and many poisons affect neurotransmitters, which can stop the nerve impulse travelling between neurons.