topic 2 - brain and eyes Flashcards
what are some limitations of treating damage and disease in the brain and other parts of the nervous system?
when nerve cells are lost, the condition is permanent and the cells do not regrow ans so they cause further permanent damage
how can the difficulties of accessing brain tissue be overcome?
using CT and PET scanners to investigate brain function
what is the function of the lens?
focusing lights onto the retina
what do sensory neurons do?
carry messages in the form of electrical impulses from receptors in the sense organs to the brain or spinal cord
what is the optic nerve?
a bundle of neurons travelling to the brain
what is an impulse?
an electrical signal down neurons
what is a synapse?
the connection between 2 neurons
what is the function of the reflex arc?
protection, its the passage of information in a reflex
what does the spinal cord do?
carried information, part of the CNS
what is the role of the myelin sheath?
insulates the electrical system, speeds up the process
what is the function of the retina?
detects light waves
what are some effects of long-sightedness?
eye ball to short
light doesnt bend
light focusing behind the retina
what are some effects of short-sightedness?
eye ball too long
retina too curved
light focused in front of the retina
what is a neuron?
a nerve cell which carries an electrical impulse
what occurs when a synapse happens?
a chemical signal (neurotransmitter) is released
what does the medulla oblongata do?
controls heart rate and reflexes
what happens when we look at objects that are far away?
our ciliary muscles are relaxed and our lens is thin
what is cancer?
the result of changes in calls that lead to uncontrolled cell division
what are the 3 types of neurones?
motor
sensory
relay
which parts of the eyes are involved in focusing?
the lens and the cornea
which type of neuron transmits a signal from the CNS to an effector such as a muscle?
motor neuron
which part of the eye controls the amount of light entering the eye?
the iris - it changes the size of the pupil in reflex actions
what is a reflex?
not learned
exists for protection
rapid, automatic response to a stimulus
what happens when you are looking at objects that arent far away?
our ciliary muscles are contracted and our lens is fat
what is cataracts?
clouding of the lens, caused by protein molecules
what makes up the CNS?
brain
spinal cord
what occurs between 2 neurons?
diffusion
what is the function of the iris?
controls pupil size
how does the nervous system receive stimuli?
through receptors
what is the function of the cornea?
fine tunes the light focusing on the retina
how can cataracts be treated?
replacing faulting lens with artificial lens
what does the cerebellum do?
divides into 2 halves, used for posture and balance
what does the cerebral cortex do?
communicated with each other, in charge of things like senses, language, memory and behaviour
