Senses Flashcards
What is the nervous system involved with?
Involved in coordination and response
What is a stimulus?
A change in the environment (external or internal) that brings about a response (generates an impulse)
What is a neuron?
A specialised cell (nerve cell) that carries electrical impulses around the body
What is an impulse?
An electrical message carried along by a neuron
What are receptors?
Cells that can detect a stimulus
Name the different types of receptors
photoreceptors (detect light),
chemoreceptors (detect or respond to chemicals),
thermoreceptors (detect temperature/ heat),
mechanoreceptors (detect physical change),
proprioceptors (detect information of where body is in space)
Name two light sensitive receptors found in the eye
Rods (views black and white (rhodopsin))
Cones (Views colour with three pigments: red, green and blue)
What body parts make up the central nervous system (CNS)?
Brain and spinal cord
What are the three types of neurons?
Motor neuron
Sensory neuron
Inter neuron
What body parts make up the peripheral nervous system (PNS)?
All nerve cells outside the CNS
Where is the cell body positioned in a motor neuron?
At one of the terminal ends of the axon
Where in the nervous system is the cell body of a motor neuron located?
Inside the CNS
What is the direction of an impulse in the CNS?
Impulse leaving the CNS
Where is the cell body positioned in a sensory neuron?
Along the axon
Where in the nervous system is the cell body of a sensory neuron located?
Outside the CNS
What direction does the impulse travel in a sensory neuron?
Into the CNS
What is the function of the cell body?
Contains the nucleus and mitochondria.
Contains neurotransmitter chemical
What is the function of the nucleus?
The control centre of the cell
What are dendrites?
Fibres that receive and carry impulses into the cell body
What is the function of an axon?
Carry impulses away from the cell body
What is the function of a schwann cell?
Makes mylein sheath
What is the function of the mylein sheath?
Fatty insulating layer that maintains the strength of the impulse.
Speeds up the impulse
What is the function of neurotransmitter swellings/ vesicles
Releases the neurotransmitter chemicals to allow the impulse across the synapse
What is a nerve impulse?
A self propagating wave of electrical change along a neuron
What generates the nerve impulse?
Ions
What is a threshold?
The minimum stimulation required for a stimulus to be sent
‘What is the all or nothing’ law?
If the threshold is reached a stimulus will be sent
What is the refractory period?
Period of time after a neuron has sent an impulse where another stimulus cannot be sent
What is a synapse?
Gap between 2 neurons
What is the function of a synapse?
Control the direction of impulse
Prevent overstimulation of effectors
Certain chemicals used can block impulses
