The brain and cranial nerves Flashcards
what is the brain important for?
emotions, memory, decision making, movement, sensation
the brain communicates via
spinal cord and 12 pr. of cranial nerves
what is the main parts of the brain?
- cerebellum 2. cerebrum 3. brainstem 4. diecephalon
what are the ventricles of the brain and its location
lateral ventricles (one in each cerebral hemisphere) third ventricle (medial to thalamus) fourth ventricle (between brain stem and cerebellum)
blood supply to brain branches from?
circle of willis
how much % of body weight is the brain?
2% and consumes 20% of oxygen and glucose blood flow to brain higher during neural activity
what are the protective coverings of the brain
- bone 2. CSF 3. meninges 4. dural partitions
what are dural partitions?
extensions of dura in deel fissures of the brain
what are the names of dural partitions in brian?
falx cerebri, falx cerebelli and tentorium cerebelli
what is blood-brain barrier?
brain capillary endothelial cells joined by tight junctions, continuous membrane, processes of astrocytes
what is the purpose of the blood-brain barrier?
prevent toxins and pathogens from getting to brain
what can cross BBB?
anesthetic, alcohol and glucose
what cannot cross BBB?
proteins, antibiotics
what is CSF?
colourless clear liquid that floats the brain and slows down movement, 80-150ml fills ventricles and surrounds CNS
what is the purpose of CSF?
protect brain, spin, transport nutrients and metabolic waste, provides stable chemical environment
what is the origin of CSF?
secreted from choroid plexuses, which are capillaries in ventricle walls that are covered by ependymal cells
what is the flow of CSF?
choroid plexuses - lateral ventricles - inter-ventricular foramen - third ventricle - cerebral aqueduct - fourth ventricle - sub arachnoid space
how is the CSF reabsorbed?
dural veneous sinus - arachnoid villi - sagittal sinus - transverse sinus - Jugular vein
what is the medulla oblongata?
continuation of spinal cord
what does the medulla oblongata contain?
ascending and descending tracts, pathways to and from cerebellum and nuclei of 5 spinal nerves
what is the medulla oblongata vital centre for?
cardiac center (force/rate of heart beat), vasomotor center (blood pressure), respiratory center (rate/depth of breathing)
what is the medulla oblongata also the center for?
coughing, sneezing, vomitting, swallowing, sweating, hiccuping
what is Pons?
bridge between midbrain and medulla, Cranial Nerve 5-7 come from
what is Pons responsible for?
controlling patterns of breathing
where is the midbrain located?
between Pons and diencephalon, cranial nerve 3 and 4 come from
what is the midbrain responsible for>?
co-ordination of muscle movement, visual and auditory reflexes
what is the reticular formation?
diffused network of neurons in brain stem that helps regulate muscle tones
what is RAS and what does it do?
Reticular Activation System = regulates levels of consciuosness=== filters sensory info except for smell before it goes to thalamus, can be turned off and on by cerebrum. turned off at night to cut off from world only auditory info in and is decided if important or not by cerebrum
what does the cerebellum do?
automatic process center, compares motor commands with proprioceptors, maintains posture, muscle tone and balance, processes smooth, co-ordinated movement.
what is cerebellum peduncles?
attached cerebellum to brainstem
what are the parts of cerebellum peduncles?
superior cerebellum peduncles, middle cerebellum peduncles, inferior cerebellum peduncles
what is superior cerebellum peduncles responsible for?
involuntary movement to midbrain
what is middle cerebellum peduncles responsible for?
voluntary movement to pons
what is inferior cerebellum peduncles responsible for?
balance sensory info from midbrain
diencephalon contains…
thalamus and hypothalamus
significance about thalamus
forms lateral walls of ventricles, relays all sensory info except smell
where does thalamus get info from?
brainstem, spinal cord, cerebellum and basal nuclei
significance about hypothalamus
controls ANS, endocrine system and homeostasis
what does the hypothalamus control?
food intake, sexual responses, emotions (agression, rage, pain pleasure), sleep patterns, water and electrolyte balance, body temperature, heart rate, hormone secretion, sexual responses
folds on bain called?
gyrus
shallow grooves of brain called?
sulcus
deep grooves of brain called?
fissures
the division of the 2 hemispheres is called?
longitudinal fissure
what is at the end of lateral fissure?
INSULA
what is corpus callosum?
bundle of white matter connecting the 2 hemispheres
what is basal nuclei?
bundle of grey matter in cerebrum
what are the 3 cerebral tracts?
commissural, projection, association cerebral nuclei, limbic system
what is commissural tract?
connection between hemispheres
what is projection tract?
afferent fibers up to cerebral cortex or efferent fibers down from cerebral cortex
what is association tract?
connection of regions within a single hemisphere
what is cerebral nuclei?
input from entire cerebral cortex, regulates muscle tone , involved in automatic movement and cognition (thought)
what is the limbic system composed of?
amygdala and hippocampus
what is the limbic system?
controls emotional aspect of behaviour, links conscious intellect from cerebrum with unconscious automatic functions of midbrain
limbic system is involved with?
memory storage and recall
what is the primary motor area?
pre-central gyrus, controls voluntary motor movement of skeletal muscles; somatotopically organized
what does somatotopically organization mean?
each area of cerebral cortex corresponds to a specific area of the body
what is the distribution of the somatotopical organization of primary motor area?
amount of cortex is devoted to body parts that are proportionate to precise motor control = more to hands and face than to legs, arm, torso
what is the premotor area significant for?
learned, repetitive motor skills eg. driving car or signing name
what is the Broca’s area?
frontal lobe near lateral sulcus mostly in left hemisphere, controls motors used in speech
pre frontal area is located
most anterior area in frontal lobe
prefrontal area is responsible for?
intellect, personality, conscious, abstract ideas, motivation, planning, goals, abstract ideas, judgement
where is olfactory area and what is it significant for?
medial temporal, inferior to frontal lobe, input from olfactory receptors, sensory area of brain
what is the primary sensory area?
area of brain where sensory info from skin and muscles proprioception is inputted located post central gyrus in parietal lobe
what is the distribution of the sensory function?
area proportional to sensitivity; somatotopically organized
where is the somatosensory association area and what is it significant for?
post primary sensory area, interpreting sensory info from past experiences
what is the gustatory area and where is it located?
tongue area of somatosensory cortex, receives sensory input from taste buds
what is primary auditory area?
receives impulses from ear, hearing
what is the auditory association area?
interprets auditory info; determines if noise, speech or music
what is Wernicke’s area?
usually in left hemisphere, where language both written and spoken is understood
what is language association area?
verbal expression of emotion (tone), detection of emotion in speech
when language goes wrong it is called
aphasia
non-fluent aphasia is?
when you know what you want to say but you cannot form the words - brocas
fluent aphasia is?
when you can speak but connections dont make sense - wernickes
primary visual area?
impulses from eye
visual association area?
adjacent primary visual area, interprets visual input
what hemispheric lateralization?
inequality in hemisphere; 90% of pop, left dominates = math, reasoning, language
