Neuroanatomy synopsis Flashcards
what separates lobes
grooves:
central sulcus
lateral sulcus
parieto-occipital sulcus
sulci separate gyri
how many lobes do we have
5 or 6
frontal
parietal
occipital
temporal
insula- hidden between banks of lateral sulcus
(limbic) sandwiched between two functional areas
what kind of movement is found in the frontal lobe
discuss dominant hemispheres
VOLUNTARY MUSCLE MOVEMENT
-primary motor cortex
-premotor cortex
LANGUAGE PRODUCTION
-Broca’s area, frontal operculum of dominant hemisphere (85% dominant in left, therefore frontal operculum involved in language production in 85%)
HIGHER COGNITIVE FUNCTIONS
-impulse control, decision-making, problem solving, social interaction, attention
-prefrontal cortex area
dominant hemisphere–>
certain functions located to one side of the brain, eg. language and mathematical abilities
discuss parietal lobe function
INTEGRATION OF SOMATOSENSORY INFO
-primary and secondary somatosensory cortices (except smell)
MOVEMENT
-primary somatosensory cortex (some neurons involved in initiating movement)
LANGUAGE
-wernicke’s area partially in the dominant hemisphere –> reading
discuss the temporal lobe function
CONSCIOUS MEMORY –REVISING :(
-medial temporal lobe (hippocampus and neighbouring cortices)
AUDITORY PROCESSING
-auditory cortices
COMPREHENSION OF SPEECH
-anterior part of wernicke’s area
OLFACTION
-medial temporal lobe
-primary olfactory cortex
what is the uncus and clinical significance
innermost part of temporal lobe (hook)
uncal herniation if increased intracranial pressure
thorugh foraman magnum
what is the function of the occipital lobe
VISUAL PERCEPTION AND PROCESSING
MEMORY
what is the function of insula
OLFACTION
TASTE
DISCRIMINATIVE TOUCH
what is the function of the limbic lobe and what does limbic mean
BEHAVIOURAL AND EMOTIONAL RESPONSES
LEARNING AND MEMORY (part is in the temporal lobe and has connections with medial temporal lobe structures)
eg. smelling curry and remembering good experiences
limbic means border- so limbic lobe frames corpus callosum and diencephalon
what forms the diencephalon
5 parts
thalamus
epithalamus
subthalamus
metathalamus
hypothalamus
what is the thalamus involved in
relay station for ALL SENSORY IMPULSES except smell before cortex
inputs from subcortical motor nuclei and cerebellum before cerebral motor cortex
what are the 6 major functions of the hypothalamus
autonomic control
endocrine control (with pituitary gland)
regulation of thirst (fluid and electrolyte balance)
eating (energy balance)
sexual behaviour, reproduction
body temp
what is the hypophysis
an endocrine gland- pituitary gland
found in pituitary fossa
superior aspect of sphenoid sinus
how does pituitary gland develop
pouches form from roof f the mouth and floor of diencephalon
these pouches join
loses connection with roof of mouth
attached to diencephalon via a stalk
where do __ develop from
neurohypophysis
adenohypophysis (anterior lobe)
neuro develops from diencephalon
adeno develops from roof of mouth
what is neurohypophysis
posterior lobe of pituitary gland
pituitary stalk
median eminence
what is the adenohypophysis
just anterior lobe
what does neurohypophysis do
secretes two hormones that is produced in hypothalamus and travels down paraventricular nuclei and supraoptic nuclei
oxyctosis
ADH
what does the adenohypophysis do
produces and secretes hormones into the hypophysial portal system
what are the parts of the midbrain
(mickey mouse shape)
Substantia nigra (eyebrows- black)
Crus cerebri (ears- leg of brain)
2 superior and 2 inferior colliculi (whiskers-bumps on posterior of midbrain) VISUAL AND AUDITORY REFLEXES
Tegmentum (superior)
Tectum (inferior)
Red nuclues (eye)
what are the superior and inferior colliculi involved in
auditory and visual reflex
what is the function of red nucleus
subcortical motor centre
what happens if there is brainstem damage above red nucleus
decorticate rigidity
in response to sharp pain
arms flex
legs extend
abnormal posturing ,
stiff
bent arms
legs straight
what is substantia nigra involved in
and what condition is it damaged in
reward seeking, motor learning
parkinsons
what does pons mean
bridge
connect forebrain and cerebellum
what is the function of pons
conduction area (bridge)
there are many nuclei that contribute to regulation of respiration, hearing and balance
what are the centres of respiration found in pons
pneumotaxic area- sends inhib signals to respiratory centres
apneustic area-stimulates inspiratory neurons of dorsal resp and ventral resp group therefore promotes inspiration
therefore regulate respiration
what is the function of medulla
vital centres that regulate resp rhythm, heart rate, bp
non-vital centres that regulate cough, sneeze, swallowing, vomiting
also where corticospinal tract crosses (90% cross in pyramidal decussaion)
what is the area postrema
found in medulla
lower part of 4th ventricle
chemoreceptor triggers this area- detects emetic toxins in blood and csf and induces vomiting (if not working die if poison)
describe the respiratory centres
found in medulla and pons
in medulla we have dorsal and ventral respiratory group, works with pneumotaxic and apneustic area.
DRG initiates inspiration and establishes rhythm of normal
neurons in DRG stimulate nerves to diaphragm and external intercostals
if DRG suppressed breathing stops
VRG for expiration
what is the reticular formation
motor and sensory nuclei of cranial nerves
neurons form a polysynaptic network around these in the brainstem, collectively called reticular (network) formation
continues rostrally into the thalamus and hypothalamus, caudally into the spinal cord
receive input and project to all parts of cns
divided into 3 longitudinal zones (5 columns)
what is the median reticular formation (raphe nuclei) involved in
sleep
pain
what is the paramedian reticular formation involved in (gigantocellular reticular nuclei)
sensory pathways
muscle tone
what is the lateral reticular formation (parvocellular reticular nuclei) involved in
ALL sensory pathways
crainial nerve reflexes and visceral functions
is reticular formation involved in state of consciousness, explain
what is its function
yes
related to cns so wide functions
sleep and wakefulness (if disturbed = coma)
pattern generation
-cv control
-respiratory control
pattern generation (non-essential)
-conjugate eye movement
-gait
swallowing, vomiting, coughing, sneezing
control of micturition
nociception and pain modulation
is ascending or descending reticular formation sensory of motor
ascending is sensory
descending is motor
what does the ascending reticular formation contain and therefore do
contains reticular activating system RAS
this awakens cerebra cortex from sleep
maintains consciousness/attention
filters incoming stimuli to discriminate irrelevant background stimuli (eg. in coffee shop and studying)
pain modulators
what does the descending reticular formation
helps maintain muscle tone- balance and tone
what is the cerebellum and its function
2 hemispheres in cerebellar fossa
connected to brain stem by cerebellar peduncles
process and interprets impulses from motor cortex and sensory pathways
coordinates motor activity for smooth, well-timed movements
important for balance
what is the difference between coma and vegetative stae
coma- eyes closed and no response
veg state- may respond vaguely to painful stimulus, eyes open, cant communicate
what are afferent neurons
nuerons, axons carry info towards the cns
what efferent neurons and the two different kinds
neuron, axon carries impulses towards the end organ
UMN- cell body in CEREBRAL CORTEX
LMN- cell body in VENTRAL HORN of SPINAL CORD/ BRAINSTEM
what are the 7 functional classifications of neurons
medial to lateral
1. general somatic efferent STRIATED VOLUNTARY MUSCLES
2. special visceral efferent MUSCLES FROM PHARYNGEAL ARCHES
3. general visceral efferent SMOOTH MUSCLES, GLANDS
- general visceral afferent ORGANS like discomfort after eating, appendicitis
- special visceral afferent OLFACTION, TASTE
- general somatic afferent PERCEPTION OF PAIN, TOUCH, TEMPERATURE
- special somatic afferent VISION, HEARING, BALANCE
SOMATIC- body, skin, muscles, bones, soft tissue
VISCERAL- internal organs blood vessels
visceral is always divided into genal and special
what is the organisation of neurons in the spinal cord to brainstem
somatic neurons are located at tip of ventral and dorsal horns
visceral found next to that
spinal cord grey matter is H shape and more vertical, this begins to open up dorsally
in brainstem, the grey matter becomes more horizontal- NUCLEI ORDER REMAINS THE SAME
what forms white matter tracts and how do we see the course of these
axons of neurons form white matter tracts
diffusion tensor imaging
what are the directions of white matter tracts and give examples
up/down- projection fibres INTERNAL CAPSULE
front/back - association fibres SUPERIOIR LONGITDINAL FASCICULUS
left/right- commissural fibres CORPUS CALLOSUM, POSTERIOR COMMISSURE
When is babinski sign normal
until 6 months old
