Chapter 14- Coordination and Responses Flashcards
What are stimuli, receptors and effectors and coordination?
Stimuli- Changes in the environment that can be detected by organisms.
Receptors- A group of cells that detect a stimuli
Effectors- A group of cells that respond to a stimuli. Muscles and glands are effectors.
Coordination: ensures that the actions fo different parts of the body work together.
The fastest way to do this is nerves, there is also a slower way with the use of hormones.
What is the axon and dendrite and what do they do? What is a nerve impulse?
Axon- helps the nerve to quickly adapt to transmit electrical signals. It’s a long thin fiber of cytoplasm that extends from the cell body of a neuron.
Dendrite- Short fibers of cytoplasm in a neuron. They pick up electrical impulses for neurons nearby.
Nerve impulse: An electrical signal that passes rapidly through an axon.
What is myelin?
Some of the nerve fibers of active animals and mammals are wrapped in a layer of fat and protein called the myelin. Every now and then there are narrow gaps in the myelin sheath.
We have seen that signals that neurons transmit are in the form of electrical impulses. Myelin insulates the nerve fibers so they can carry impulses much faster.
What is the central nervous system and peripheral nervous system?
\The CNS is made up of the brain and the spinal cord. It is made up of neurons. ITs roles it to coordinate the electrical impulses traveling through our nervous system
The peripheral nervous system are nerves outside the brain and spinal cord. Each nerve contains hundreds of neurons. This system also contains our sense organs.
What is reflex action and reflex arc?
Reflex action: Means of automatically and rapidly integrating and coordinating stimuli with response of effectors
Reflex arc: A series of neurons that transmit electrical impulses from a receptor to an effector.
How does our nervous system deal, the transmitting of messages?
When a receptor detects a stimulus, it sends an electrical impulse along a neuron to the brain or spinal cord. These will receive the impulse, and will send the impulse across the appropriate nerve fibers, to the appropriate effector.
What is a sensory neuron, and how does it work?
When our finger touches something. A sensory receptor will detect this. It converts ito an electrical impulse, which travels to the spinal cord along the axon to the from the receptor cell. This receptor cell is known as sensory neuron. A neuron that transmits electrical impulses from a receptor to the central nervous system.
What is a relay neuron, and how does it work?
One the electrical impulse is received into the central nervous system, the relay neurone, ensures that it goes to the brain. It transmits the electrical impulses to other neurons in the CNS. They also pass it on to a motor neuron to pass it to an effector.
What is a synaptic gap and synapse
Synaptic gap: A tiny gap between two neurons at a synapse.
Synapse: A junction between 2 neurons
What is neurotransmitter and vesicle?
Inside a sensory neurons’ axoz there are hundreds of tiny vacuoles or vesicles. These contain a huge number of molecules of a chemical called the neurotransmitter.
Vesicles: Very small vacuole
Neurotransmitter: A chemical stored in the vesicles at the end of the neurons, which can be released to diffuse across the synaptic gap and set up as an electrical impulse in the next neuron.
What happens when an electrical impulse arrives on the axon of the sensory neurone?
When an electrical impulse arrives on the axon of the sensory neurone, it causes vesicles to move from the cell membrane of the sensory neuron. They fuse with the membrane and empty their contents, into the synaptic gap .
How do neurotransmitters attach themselves to recepetor proteins, whats the reason.
The nuerotransmitter easily diffuses across the tiny gap. The molecules of the nuerotransmitter attach to receptor proteins in the cell membrane of the relay nuerone. This happens because the shape of the neurotransmitter and relay neurons are complementary.
How does this pass on to the next synapse, what do synapses ensure.
This binding, triggers an electrical impulse in the relay nuerone, and it goes from one relay nuerone to anoterh, and then to the next synapse. Synapses are like one way valves, there is only neurotransmitters on one side of the synapse, so impulses can only go from that side. The nerve impulses ensures that impulses go in one direction.
