neurons and localisation of brain function Flashcards
what are neurons?
they are nerve cells that process and transmit messages through electrical and chemical signals.
neurons are the basic building blocks of the NS.
what are the 3 types of neurons?
sensory
relay
motor
what do the sensory neurons do?
sensory neurons carry messages from the PNS to the CNS
what do sensory neurons look like?
sensory neurons have long dendrites and short axons.
what do relay neurons do ?
relay neurons connect sensory neurons to motor or other relay neurons.
what do relay neurons look like?
relay neurons have short dendrites and short axons.
what do motor neurons do?
motor neurons connect CNS to effectors such as muscles and glands.
what do motor neurons look like?
motor neurons have short dendrites and a long axon.
what is similar and different between all neurons?
neurons have the same basic structure but vary in size.
name all 6 parts of a neuron…
a neuron is made of …
cell body (soma), axon, dendrites, myelin sheath, nodes of Ranvier, axon terminals
what does the cell body (soma) do?
the cell body includes a nucleus that contains the genetic material of the cell
what are dendrites and what do they do?
dendrites are branchlike structures that protrude from the cell body. They carry nerve impulses away from the body and down the length of the neuron.
what is axon?
an axon is a portion of a nerve cell (neuron) that carries nerve impulses away from the cell body down the length of the neuron.
what is the axon covered in?
the axon is covered in a fatty layer called the myelin sheath.
what is the myelin sheath?
the myelin sheath is a fatty layer that protects the axon and speeds up the rate of chemical transmission of an impulse
the myelin sheath is segmented by gaps called the what?
the Nodes of Ranvier
what are the nodes of Ranvier?
nodes of Ranvier are gaps in the myelin sheath that speed up the rate of chemical transmission of an impulse by forcing it to jump across gaps along the axon.
what are the terminal buttons?
terminal buttons are located at the end of the neuron and are responsible for sending the signal on to other neurons.
they communicate with the next neuron in the chain across a synapse.
where are sensory neurons most commonly located?
they are most commonly located in the ganglia
relay neuros make up what % of all neurons?
relay neurons make up 97% of all neurons
where are relay neurons located?
relay neurons are located within the brain and visual system.
where are the motor neurons located?
the cell bodies of motor neurons are found in the CNS , but they have long axons which form part of the PNS.
what is localisation of function in the brain?
localisation of function in the brain is the theory that different areas of the brain are responsible for specific behaviours, processes or activities.
before localisation of brain function, what theory was accepted for brain function?
before, a more holistic theory of brain function was accepted - all areas of brain were involved in processing of thoughts and actions
what is the outer layer of the hemispheres called?
the cerebral cortex
what are the 2 hemispheres divided into?
the 2 hemispheres are divided into 4 lobes
what are the 4 lobes?
frontal,
parietal,
occipital,
temporal
what is located at the back of the frontal lobe?
the motor area
what does the motor area do?
the motor area controls voluntary movements in the opposite side of the body.
is the motor area present in both hemispheres?
yes
what happens is the motor area is damaged?
damage to this area could result in a loss of control over fine movements.
what is located at the front of the parietal lobe?
somatosensory cortex
what is the somatosensory cortex responsible for?
the somatosensory cortex is responsible for receiving and processing sensory information from across the body, such as touch, temperature, and pain.
what is located in the occipital area?
visual area
what does the visual area do?
receives and processes visual info.
what can damage to the visual area lead to?
it can result in blindness to the opposite VF
What is located in the temporal lobe?
auditory area
what does the auditory area do?
the auditory area is concerned with the analysis of speech-based info
what area of the brain is language restricted to in most people?
the left hemisphere
what happened in the 1880s with regards to the area of the brain responsible for speech production?
Paul Broca identified an area in the left frontal lobe that is responsible for speech production. This area is Broca’s area
what is Broca’s area responsible for?
speech production
where is Broca’s area?
in the left frontal lobe.
what can happen is Broca’s area is damaged?
damage to Broca’s area may lead to Broca’s aphasia
what is Broca’s aphasia characterised by?
Broca’s aphasia is characterised by slow, laborious speech lacking in fluency
who was Broca’s most famous patient?
Tan
why was Tan called Tan?
Tan was called Tan as Tan was the only word that he could say
people with Broca’s aphasia have trouble with…
prepositions and conjunctions
who identified Wernicke’s area?
Karl Wernicke
where is Wernicke’s area?
in the left temporal lobe
what is Wernicke’s area responsible for?
Wernicke’s area is responsible for language understanding
people with damage to their Wernicke’s are have no problem with what? but they have difficulty with what?
people with damage to their Wernicke’s are have no problem with producing language but they have difficulty understanding it
what is damage to Wernicke’s area called?
Wernicke’s aphasia
people with Wernicke’s aphasia will often produce what?
people with Wernicke’s aphasia will produce nonsense words (neoglisms) as part of the content of their speech.
