B1 - The nervous system Flashcards
What is monocular vision?
Monocular vision is where each eye is used separately.
What is binocular vision?
Binocular vision is where both eyes are used together.
What are the advantages to monocular vision?
The main advantage to monocular vision is that you are capable of having a wider field of view.
What are the disadvantages to monocular vision?
The eyes are not very good at judging distance.
What are the advantages to binocular vision?
The eyes are good at judging distance.
What are the disadvantages to binocular vision?
You do not have a wide field of view.
What are the different sense organs?
- ears
- nose
- tongue
- eyes
- skin
Which sense organ reacts to a change in temperature?
The skin detects pressure, temperature and pain.
How does binocular vision work?
Binocular vision produces two images and the brain compares the two images. The more similar they are, the further away is the object they are looking at.
What does the cornea do?
Refracts light - bends it as it enters the eye.
What does the iris do?
Controls how much light enters the pupil.
What does the lens do?
Focuses light onto the retina.
What does the retina do?
Contains the light receptors.
What does the optic nerve do?
Carries impulses from the eye to the brain.
What do ciliary muscles and suspensory ligaments do?
They work together to alter the shape of the lens.
What causes red-green colour blindness?
Red-green colour blindness is an inherited condition where people do not have specialised cells in the retina.
How is short sight corrected?
Diverging lens bends the light rays outwards before they enter the eye.
How is long sight corrected?
Converging lens bend light rays inwards before they enter the eye.
What is a reflex?
A muscular action that we take without thinking.
Why do reflex actions protect us?
They are fast and automatic.
What is the central nervous system made up of?
The brain and the spinal cord.
What is the peripheral nervous system made up of?
Nerves to and from the brain and spinal cord.
What do neurons carry?
Neurons carry nerve impulses.
What do sensory neurons do?
Sensory neurons carry impulses away from sensory receptors.
What do motor neurons do?
Motor neurons carry impulses to an effector.
What are the different parts of a motor neuron?
- axon
- sheath
- nucleus
- cell body
- dendrites
How are neurons adapted to carry and pass on nerve impulses quickly?
Neurons:
- are long
- have branched endings to pick up impulses
- are insulated by a fatty sheath to prevent loss of impulse
What is a synapse?
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter
