the brain Flashcards
what is the brain composed of?
interneurons and neuroglia
what do interneurons and neuroglia organise into within the brain?
areas of gray and white matter
what does gray matter contain?
- neuroglia
- cell bodies of interneurons organised into nuclei
what does white matter contain?
- neuroglia
- myelinated axons of interneurons organised into tracts
what are the major parts of the brain?
- cerebellum
- cerebrum
- diencephalon
- brain stem
what areas are part of the diencephalon?
- thalamus
- hypothalamus
- epithalamus
what areas are part of the brain stem?
- midbrain
- pons
- medulla oblongata
what is the largest part of the brain?
cerebrum
how are the two cerebral hemispheres divided?
by the longitudinal fissure (deep grove)
how is the cerebrum separated from the cerebellum?
transverse fissure
what is a ridge on the convoluted surface of the brain called?
gyrus/gyri
what are the shallow grooves on the convoluted surface of the brain called?
sulcus/sulci
why is the entire surface of the brain convolutes?
increases surface area= more neurons
what are the five lobes of each cerebral hemisphere?
- frontal
- parietal
- temporal
- occipital
- insula
what three regions is the cerebral hemisphere divided into internally?
- cerebral cortex (gray matter)
- cerebral white matter
- basal nuclei
what are the three main functional areas of each cerebral cortex?
- motor areas
- sensory areas
- association areas
what do the motor areas of each cerebral cortex control?
control voluntary skeletal muscle movements
what do the sensory areas of each cerebral cortex control?
- receive and localise sensory input
- allows sensation perception
what do the association areas of each cerebral cortex control?
- interpret incoming input to make sense of
- coordinate intellectual function, store memories and determine behaviour/personality
what lobe are motor areas of the cerebral hemispheres located in?
frontal lobe
where is the primary motor cortex located in the cerebrum?
precentral gyrus of each frontal lobe
what does the primary motor cortex generate?
somatic motor output for voluntary skeletal muscle movement
what does damage to the primary motor cortex result in?
paralysis
what do motor association areas plan and coordinate?
voluntary motor activities
what does the motor association areas act via?
primary motor cortex
what do the motor association areas include?
- frontal eye field
- Broca’s area
- premotor cortex
what does the frontal eye field control of the motor association areas?
voluntary eye movements
what does the Broca’s area control of the motor association areas?
muscles involved in speech production
what does the premotor cortex control of the motor association areas?
controls learned, skilled motor activities of complex nature
what does damage to the premotor cortex result in?
loss of complex motor skills
what lobes are the sensory areas of the cerebral cortex located in?
- insula
- parietal
- temporal
- occipital
how do the sensory areas of the cerebral cortex allow sensations to be perceived?
- general sensory receptors
- special sensory receptors
what are general sensory receptors responsible for?
pain, temp, touch, vibration, pressure and proprioception
what are special sensory receptors responsible for?
vision, smell, taste, hearing and balance
where is the primary somatosensory cortex located within the cerebrum?
in the postcentral gyrus of each pariental lobe
what does the primary somatosensory cortex receive?
general sensory info
what does the primary somatosensory cortex perceive sensations of?
touch, pain, vibration, pressure, temp and proprioception
what does the primary somatosensory cortex locate?
the origin of the stimulus (sensory input)
what does the somatosensory association area receive?
general sensory input from the primary somatosensory cortex
what do the somatosensory association areas interpret?
incoming general sensory input and compares to stored memories
what does damage to the visual cortex result in?
functional blindness
what are the visual areas of the special sensory areas?
- visual cortex
- visual association area
what does the visual cortex of the special sensory areas receive?
visual input detected by photoreceptors
what does the visual association areas of the special sensory areas interpret?
interprets visual input, allows us to recognise what we see and stores memories of past images
what are the auditory areas of special sensory areas?
- auditory cortex
- auditory association area
where is the olfactory cortex of the special sensory areas located?
temporal lobe
what does the olfactory cortex of the special sensory areas perceive?
different odours
where is the gustatory cortex of the special sensory areas located?
insula
what does the gustatory cortex of the special sensory areas perceive?
taste sensations
where is the visceral cortex of the special sensory areas located?
insula
where is the vestibular cortex of the special sensory areas located?
insula
what does the visceral cortex of the special sensory areas perceive?
visceral sensations eg. upset stomach
what does the vestibular cortex of the special sensory areas perceive?
awareness of balance
what does Wernicke’s area of the cerebrum invlove?
language comprehension allows us to understand written and spoken language
where is the Wernicke’s area of the cereberum located?
left temporal lobe of the left hemisphere only
where is the prefrontal cortex of the cerebrum located?
located in each frontal lobe
what is the responsibility of the prefrontal cortex?
our intelligence (cognition), personality and behaviour
what does the damage to the prefrontal cortex result in?
personality disorders
what is cerebral white matter composed of?
myelinated axons organised into three types of tracts
what are the three types of tracts of cerebral white matter called?
- commissural tracts
- association tracts
- projection tracts
what are commissural tracts conducting?
conducting between the two cerebral hemispheres
what are association tracts conducting?
info between cortical areas in the same hemisphere
what are projection tracts conducting?
info between the cerebral cortex and lower parts of the CNS
what is the cerebral basal nuclei?
islands of gray matter deep within white matter
what is the main function of white matter?
communication within the CNS
what is the main function of the basal nuclei?
facilitates smooth skeletal movements
what is the second largest part of the brain?
cerebellum
what is the inner region of white matter within the cerebellum called?
arbor vitae
what is the outer cortex of gray matter of the cerebellum called?
cerebellar cortex
what does the cerebellum ensure?
smooth, coordinated skeletal muscle movements and maintains posture and balance
what does the thalamus do?
relays sensory input to the correct cerebral destination
what does the hypothalamus control?
activities of the autonomic nervous system
what does the hypothalamus regulate?
- emotions
- body temp
- hunger and thirst
- sleep/wake cycles
- produce hormones
what does the epithalamus include?
pineal gland
what does the pineal gland produce?
melatonin which induces sleep
what does the limbic system control?
emotions
what does the hippocampus as a part of the limbic system convert?
short-term memories to long-term
white matter within the brain stem is composed of?
axon tracts
what do axon tracts within the brain stem conduct?
sensory and motor info through brain stem
what does gray matter within. the brain stem contain?
nuclei
what are some of the nuclei in the brain stem associated with?
the ten cranial nerves that arise from the brain stem
what cranial nerve nuclei control eye movement in the midbrain?
CN |||- |V
what cranial nerve nuclei involves taste, chewing, eye movements, hearing, balance and facial sensation/expression?
CN V-V|||
what cranial nerve nuclei is involved in swallowing, tongue movements. and digestive functions?
CN |X, X and X||
what system does the reticular formation contain?
the reticular activating system
what does the reticular activating system maintain?
consciousness
what does damage to the reticular activating system result in?
coma
what are brain disorders?
- traumatic brain injuries
- stroke
- transient ischaemic attacks
- alzhiemer’s disease
- parkinson’s disease
-where do head injuries damage the brain?
at injury site and on opposite side as brain hits skull
what is a concussion?
mild brain injury with short-lived effects
what are some symptoms of concussion?
headache, dizziness, temporary loss of consciousness
what is contusion?
bruising of the brain, may cause permanent neurological damage and result in a coma
what is the most common nervous system disorder?
stroke
how does a stroke occur?
blood flow to the brain is reduced or blocked (ischaemia) and neurons die
what are the causes of strokes?
- blood clot in cerebral artery
- ruptured blood vessel
what results after there is a blood clot in the cerebral artery?
ischaemic stroke (most common)
what results if there is a ruptured blood vessel in the brain?
hemorrhagic stroke
what are common stroke symptoms?
- headache
- muscle weakness/paralysis (usually face/arm)
- loss of vision/blurred
- difficulty speaking/understanding
how long can symptoms of a stroke last?
24hrs-life
how does a Transient Ischaemic Attack occur?
blood flow to the brain area is temporarily reduced or blocked but no neurons die
what are the symptoms of a Transient Ischaemic Attack?
as per stroke but usually last 5-10mins, warning of an impending stroke
what is Alzheimer’s disease?
progressive degenerative disease that causes death of neurons and therefore shrinkage of the brain. Particularly affects hippocampus and prefrontal cortex
what are the symptoms of Alzheimer’s?
- memory loss (especially short-term)
- confusion
- personality changes
what is Parkinson’s?
progressive degenerative disease of dopamine-releasing neurons of the substania nigra
what are the symptoms of Parkinson’s?
- persistent tremors at rest
- shuffling walk
- difficulty swallowing
- stiff facial expressions
what is CN I?
olfactory
what is the function of the olfactory cranial nerve?
smell
what is CN II?
optic
what is CN III?
occulomotor
what is CN IV?
most eye movements
what is CN V?
trigeminal
what is CN VI?
abducens
what is CN VII?
facial
what is CN VIII?
vestibulocochlear
what is CN IX?
glossopharyngeal
what is CN X?
vagus
what is CN XI?
accessory
what is CN XII?
hypoglossal
what is the function of the cranial optic nerve?
vision
what is the function of the cranial occulomotor nerve?
most eye movements
what is the function of the cranial trochlear nerve?
moves eye
what is the function of the cranial trigeminal nerve?
face sensation, mastication
what is the function of the cranial abducens nerve?
abducts the eye
what is the function of the cranial facial nerve?
facial expression, taste
what is the function of the cranial vestibulocochlear nerve?
hearing and balance
what is the function of the cranial glossopharyngeal nerve?
taste, gag reflex
what is the function of the cranial vagus nerve?
gag reflex, parasympathetic innervation
what is the function of the cranial accessory nerve?
shoulder shrug
what is the function of the cranial hypoglossal nerve?
swallowing, speech
is the nerve type sensory, motor or both of the olfactory cranial nerve?
sensory
is the nerve type sensory, motor or both of the optic cranial nerve?
sensory
is the nerve type sensory, motor or both of the occulomotor cranial nerve?
motor
is the nerve type sensory, motor or both of the trochlear cranial nerve?
motor
is the nerve type sensory, motor or both of the trigeminal cranial nerve?
both
is the nerve type sensory, motor or both of the abducens cranial nerve?
motor
is the nerve type sensory, motor or both of the facial cranial nerve?
both
is the nerve type sensory, motor or both of the vestibulocochlear cranial nerve?
sensory
is the nerve type sensory, motor or both of the glossopharyngeal cranial nerve?
both
is the nerve type sensory, motor or both of the vagus cranial nerve?
both
is the nerve type sensory, motor or both of the accessory cranial nerve?
motor
is the nerve type sensory, motor or both of the hypoglossal cranial nerve?
motor
