Neuroscience CH 4 Flashcards
Examining autopsy tissue has the allowance but also the drawback of…
Allowing neuroscientists to see what our brains look like but has the obvious drawbacks of telling them about how the systems work alive
What do neuropsychologists do? What does this help us conquer?
test the behaviour of patients with damage to certain parts of their brain. This allows us to know which parts of the brain do what depending on what part of the brain is damaged and what the patient therefore lacks in.
What is the drawback of neuropschologist work?
Inferences are made about the brain without possible smaller abnormalities being recognized that may cause the problem
Electroencephalograms are used for
recording brain activity or brain waves from the surface of the scalp during certain states such as awake or asleep
What is lesioning
destroying specific brain areas to see how behaviour changes
What are neuroimaging techniques used for
show visual images in awake humans
MRI, fMRI, PET, CT scans are all
neuroimaging techniques
Clinical observation allows
discovering of a number of brain disorders
What is a brain lesion?
Experimentally destroys brain tissue to study animal behaviours after such destruction
What is PET?
Positron Emission Tomography Scan is a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task
What is MRI scan?
Magnetic resonance imaging uses magnetic fields and radio waves to produce computer generated images that distinguish among different types of brain tissue
What are neurone?
(nerve cell) main building block of the brain
What are the three types of neurons?
sensory, motor, interneuron
Which neurone gathers sensory info
sensory
which neurone communicates info to muscles
motor
which neurone carries info between neurone in the brain and the spinal cord?
interneuron
Which neuron is unipolar?
interneuron
which neurone is bipolar?
sensory
which neurone is multipolar
motor
What is a cell body?
it contains the nucleus which provides energy for the neuron
What are dendrites
receive messages from other neurons
what does the axon fo
carries info away from the cell body
what does the axon terminals do
transmits signals to the dendrites on the next neurone
What is the myelin sheath?
a substance that speeds up the firing of the neuron
What do the nodes of ranvier do?
they are the small gaps on the neurone that have no myelin covering
what is the order of the neurone from one dendrite to the next
dendrite - cell body - axon - myelin sheath - nodes - terminals - muscle
Glia?
cells that help support neurons and basically also make up the nervous system
What do astrocytes do? (3)
They create blood-brain barrier, influences communication between neurone and helps heal brain damage
what are oligodendroglia
provide myelin to speed up transmission of neurons
what are microglia?
clean up dead cells and prevent infections in the brain
list the three types of glia
astrocytes, oligodendroglia, microglia
Cells are surrounded by (a) and contain (b). Both fluids contain charged particles called (c)
extracellular fluid/intracellular fluid/ions
When is the resting potential?
when a neurone is at rest
The neurone is more negatively charged inside or outside of the cell? (-70mv)
inside
The resting charge is maintained through the actions of….
sodium-potassium pumps
neurone send messages to one another via electrochemical actions meaning….
chemicals cause an electrical signal to be generated
A sudden charge of a neurone axon causes it to release a chemical called….. thereby passing an electrical signal from one neurone to the next
neurotransmitter
Neurons are covered by a
membrane
ions are molecules that contain a relative imbalance of…..
protons or electrons and thus either are negatively or positively charged
When a neuron is said to not be sending a message it is considered to be
resting
What is the term that is described as allowing crtain ions to flow back and forth through ion channels?
selective permeability
Ion channels open and close in response to messes received from
the cells
Resting potential is maintained or changed by these specific ions
Na+, K+ and CL-
What ion is positively charged and higher concentration outside the cell?
sodium Na+
What ion is positively charged and higher concentration inside the cell?
Potassium K+
What ion is negatively charged and has higher concentration outside the cell?
CL- Chloride
unequal distribution of ions inside and outside cell establishes a
concentration gradient
Concentration gradient changes when…
electrical charge causes ion channels to open and allow more Na+ to flow into the cell
When a neurone fires it is the…
action potential
What is the four steps of action potential?
- Ion channels open to let the positive chard (Na) in.
- If inside of cell reaches a certain threshold of -50mv and action potential occurs
- The action potential moves down the membrane of the axon
- As the action potential moves past a part of the membrane the na/k pump works to restore the membrane to resting potential
Na+ goes (a) the cell during action potential while K+ goes (b)
in/out
What are the regions of bare axon that are between the areas wrapped in myelin called?
nodes of ranvier
What allows action potentials travel down the axon by jumping?
nodes of ranvier
What is plasticity
repeated release of neurotransmitters that can cause permanent change to the neurons
What is all or none?
Either a neurone is sufficiently stimulated in threshold to start an action potential or it is not
After firing, a neurone can’t fire for a 1000th of a second. What is this called?
Refractory period
What is an absolute refractory period?
a short time after an action potential during which a neurone is completely unable to fire again
what is a relative refractory period?
just after the absolute refractory period during which a neurone can only fire if it receives a stimulus stronger than its usual threshold level
When an action potential reaches the end of the axon it triggers the release of
neutransmitters
Neurotransmitters are chemicals that help neighbouring neurons
talk to eachother
Neurotransmitters float from the (a) of one neurone and are taken up by the (b) in a neighbouring neuron
synaptic vessel and neurotransmitter receptors
What is the synapse?
the small space between neurons
What is the lock and key mechanism?
neurotransmitters bind to the receptors of the receiving neuron in a key-lock mechanism
3 functions of acetylcholine
activate motor neurons for skeletal muscles, contribute to the regulation of attention/arousal/memory, some AVh receptors are stimulated by nicotine
5 functions of dopamine
voluntary movement, pleasurable emotions, decreased levels of it is involved with parkinsons disease, overactivity of DA synapses is associated with schizophrenia, cocaine elevates activity at DA synapses
2 functions of norepinephrine
contributes to modulation of mood and arousal, cocaine elevate activity at NE synapses
Abnormal levels of serotonin may contribute to
depression and OCD
serotonin is involved in regulation or
sleep, wakefulness, eating, agression