The brain Flashcards
(40 cards)
what is the cerebrum divided into
cerebrum is divided into two halves known as the cerebral hemispheres
The hemispheres are joined together by a band of nerve fibres known as the corpus callosum
what is the thin outer layer of the cerebrum known as
the cerebral cortex
this consists of the cell bodies of neurones
It is highly folded, which increases its surface area and allows it to contain a greater number of neurones
With more neurones in the brain, more neurone connections can be made
greater the ability of the brain to carry out more complex behaviours
what is beneath the cerebral cortex
‘white matter’
The white matter consists of the myelinated axons of neurones
what does hypothalamus monitor
the blood as it flows through the brain and, in response, releases hormones or stimulates the neighbouring pituitary gland to release hormones
4 functions of the hypothalamus
Regulating body temperature
Osmoregulation
Cells in the hypothalamus monitor the water balance of the blood and releases the hormone ADH if the blood becomes too concentrated
Regulating digestive activity
Controlling endocrine functions
what does the cerebellum do
cerebellum coordinates movement
what does medulla contain
co-ordination centres that control different functions
The cardiac centre controls heart rate
The respiratory centre controls breathing rate
How does CT scan work
produce cross-section images of the brain using x-ray radiation
A beam of x-rays are aimed at a patient
Digital x-ray detectors are used to pick up the x-rays as they exit the patient’s body
Denser tissue absorbs more of the x-ray radiation so shows up as a lighter region on a scan
What is CT scan good for
shows physical structures of the brain and allows visualisation of any tissue damage
blood is less dense than brain tissue so a CT scan can be used to locate damaged blood vessels and areas of bleeding after a patient has had a stroke
who is CT scan not recommended for
pregnant patients or children due to the risks of exposure to the X-ray radiation, which is given at a higher level than in a normal X-ray
How does MRI work
a combination of a magnetic field and radio waves to generate images through the body
what can be seen using MRI
Soft tissues
identify and locate tumours in the brain
MRI vs CT
MRI scans are considerably more expensive to carry out than CT scans
but do not carry the risk associated with the use of potentially harmful x-rays
difference between fMRI and MRI
fMRI scans allow brain function to be studied in real time
how does fMRI show which brain region is active
location of oxygenated blood indicates
which brain regions is active
what does fMRI scanner measure
measures the ratio of oxygenated to deoxygenated haemoglobin
what does PET scan use
radioactive tracers which collect in areas where there is increased blood flow
what is the visual cortex
region of the cerebral cortex in which visual information is processed
what is the cerebral cortex
the outer layer of the cerebrum
what is a critical period
stages in the lifespan of an organism where it is particularly sensitive to a specific stimulus which is required for the organism to develop properly.
what is habituation
If a stimulus is repeated many times with no negative outcome, then an animal will learn not to respond to it
what happens due to habituation
fewer calcium ions move into the presynaptic neurone on arrival of a nerve impulse
As a result, less neurotransmitter is released and an action potential is less likely to be generated in the postsynaptic neurone
what is Parkinsons disease
a brain disorder that affects the co-ordination of movement, caused by the loss of neurones in some parts of the brain
what do the lost neurones in parkinsons disease normally produce
neurotransmitter dopamine
Dopamine is involved in muscle control
Individuals that suffer from Parkinson’s disease produce insufficient amounts of dopamine due to the loss of dopamine-producing neurones