medsci 142 nervous and endocrine Flashcards
left dominance
for language
frontal association cortex responsible for
intelligence, personality, behaviour mood and cognitive function
Parietal association cortex
spatial skills, 3d recog (shapes faces concepts abstract perception)
temporal association cortex
memory mood aggression and intelligence.
Precentral gyrus
before central sulcus and in frontal lobe, homonculus mapping structure as primary motor cortex, containing large motor neurons (Primidial neurons /motor neurons). Big neurons for long axons connecting to periphery.
pre motor/planning cortex
before pre central gyrus with similar homonculus mapping, tells primary motor cortex when specific movement needs to occur and plans motor movement (coordinates)
Post central gyrus
PRIMARY SENSORY CORTEX behind central sulcus in parietal lobe, has similar homonculus mapping, responsible for sensory reception with small granule cells.
Mcdonalds in parietal lobe
contains two marginal gyrus
Supra marginal gyrus
part of maccas and responsible for reading in parietal lobe
angular marginal gyrus
part of maccas for writing in parietal lobe
behind parietal lobe
parieto occipital sulcus
parieto occipital sulcus
at the division between the parietal and occipital lobes
primary visual cortex
behind the parieto occipital sulcus, visual periphery info from eye goes to secondary visual cortex in rest of occipital lobe and some of temporal lobe. Interpreting visual haps in periphery.
secondary visual cortex
in occipital lobe and takes info from primary visual cortex.
lateral/sylvian fissure
begins near the basal forebrain and extends to the lateral surface of the brain separating the frontal and parietal lobe from the temporal lobe.
primary auditory cortex
part of temporal lobe and a bit of parietal lobe within sylvian fissure, takes sound and organises into a system of tones and time.
Wernickes area
secondary cortical area under the primary auditory cortex in the temporal lobe responsible for interpreting speech and language.
The cerebrum
‘seat of intelligence’ provides ability to read, write and speak. Contains outer cerebral cortex, internal reigon of cerebral white matter and gray matter nuclei deep within white matter.
primary somatosensory area
1, 2 and 3 located behind central sulcus (primary sensory area- post central gyrus)
primary gustatory area
base of post central gyrus superior to the lateral cerebral sulcus in parietal cortex. Receives impulses for taste and involved in gustatory perception and discrimination.
Primary olfactory area
in temporal lobe receives impulses for smell and involved in olfactory perception.
Brocas speech area
located in the frontal lobe close to lateral cerebral sulcus. Nerve impulses from this area pass through the premotor regions that control muscles of the larynx, pharynx and mouth resulting in specific, coordinated muscle contractions. (Speech formation).
Association areas
association areas connected to one another via association tracts
sensory homonculus
distorted somatic map of the body, where somatic sensations originate. Representation of the human body in the brain and the different areas of the brain correspond to areas of the body
Exner’s area
above brocas, involved in both writing and reading and anterior to primary motor control area.
arcuate fasciculus function
white matter bundle of short and long fibers connecting the parietal, temporal and frontal lobes. Which aligns speech recognition/comprehension with speech production.
Majority of the population is dominant in what side of the brain?
Left, and right non-dominant. The Left is dominant for language as there is the wernickes, brocas areas and supra/angular gyruses.
What happens when there is a lesion or damage to the wernickes area
Wernickes sensory aphasia, or fluent aphasia, where the person cannot interpret language well but can still communicate their ideas.
What happens when there is a lesion or damage to the Brocas area
Broca’s aphasia/ non fluent or motor aphasia. The difficulty to express ideas and feelings but can understand language.
Arcuate fasciulus
A bundle of white matter (long and short fibres) that connects the Wernickes and Brocas area
White matter
consists of axon tracks out of neurons that transmit impulses across more distant regions of the brain and spinal cord.
Grey matter
The cell bodies of neurons and their dendrites.
What happens when there is a lesion or damage to the arcuate fasciulus?
Connectional aphasia, where the connection between brocas and wernickes area is damaged, hence language difficulties will occur.
Broca’s area
Located in the frontal lobe near the premotor/planning cortex (or in). The planning part of the cortex and responsible for speech planning.
Cingulate gyrus
visible in the medial view of the brain above ventricles in the brain.
What part is the forebrain?
Contains the entire cerebrum and several structures directly nestled within it
Where is the midbrain?
Under the hypothalamus at the top most part of the brain stem.
Which parts are the hind brain?
The lower part of the brain and most of the brain stem and cerebrum.
What are the protective structures of the spinal cord?
The three meninges
What are the three meninges?
The Pia mater, Arachnoid mater and Dura mater.
What passes through the dorsal root of the spinal cord?
The sensory fibres of the spinal nerve
What passes through the ventral root of the spinal cord?
the motor fibres of the spinal nerve
Fasciculus
bundle of white matter
Wernickes area fasciculus
joins to brocas area, supra marginal gyrus and angular marginal gyrus for its left side dominance in language
Non dominant hemisphere
Non verbal language (body language), emotional expression (tone of language), 3D spatial skills, conceptual understanding and music/artistic skills.
Injury to the non dominant hemisphere results in
loss of non verbal language, speech lacks emotion, spatial disorientation, inability to recognize familiar objects and loss of musical appreciation.
How many cervical nerves
8 paired vertebrate + nerves that have a cervical enlargement around the 5-6th to accommodate for the large amount of information coming to the spinal cord from the arms.
Thoracic nerves
12 nerves under the cervical nerves that corresponds to one set of ribs per nerve, no enlargement as there are no large limbs.
Lumbar nerves
Located under thoracic nerves, 5 nerves with a lot of thin fibres (caudal equina) which are completely bathed in cerebrospinal fluid
cerebrospinal fluid
Located in and around the hollow spaces of the brain and spinal cord, acts as a cushion for shock and supports the brain + providing lubrication to surrounding bones.
The spinal cord is protected by
3 distinct layers called the meninges.
First protective layer of the meninges
Pia mater, tightly clings onto the surface of brain and spinal cord, delicate.
second protective layer of meninges
Arachnoid mater which is attached and detached in different parts that cover the brain and spinal cord.
the third protective layer (meninges)
‘tough mother’ protects and keeps cerebrospinal fluid inside the spinal cord
Dorsal rootlet
Rootlets approx 5 per level on the spinal cord to distribute information across the spinal cord. One side of the spinal cord info going into spinal cord and areas where info going out to motor control neurons to control muscle cause rootlets to come together to form a single nerve.
Spinal nerve
The coming together of a dorsal and ventral root and its information to and from periphery.
Coming together of Pia mater
Pia mater comes together and forms a string like fibre surrounded by cerebrospinal fluid around conus medullaris.
Dura mater coming together
forms a fluid filled sack and creates a string called filum Terminale externum string that holes the spinal cord down (anchored for movement.
Dermatome
areas of the skin on the body that relies on specific nerve connections on the spine. Each spinal nerve corresponds to a specific dermatome which is mapped out over the entire body.
Myotome
group of muscles that is innervated by single spinal nerve root. Myotomes are mapped out on the musculature of the body. Each spinal nerve root carries motor (and sensory) fibers that innervate specific muscles in a predictable pattern.
Difference between myotome and dermatome
dermatomes control sensation while myotomes control movement
Touch meissners corpuscle/ pressure paccinian corpuscle
An encapsulated receptor that surrounds end of neuron and sits within skin. Surrounded by myelin which increases efficiency and fire rate it is constantly firing in response to the periphery.
Touch meissners corpuscle nerve fibres and the fire rate.
Pseudo uni polar neurons 50m/s
Where does the pseudo uni polar neuron fibres go
into the spinal nerve and then dorsal root ganglia (bunch of neurons) in the enlargement where the cell body sits, then fibres go into either two parts of the spine?
Free nerve ending responding to pain/temp
Only occasionally activated therefore unmyelinated (not encapsulated) and insensitive to touch, fires at 1m/s, significantly slower.
Where does the pain/temp free nerve ending go?
discriminative information
Touch or pressure. The ability to discern between different tactile stimuli such as the location of objects touching the skin
non discriminative information
pain and temperature (cant really localise the information like touch/pressure)
The spinal cord inside is filled with what? and divided into how many sections of function?
grey matter cell body neurons with three distinct areas.
Inside of spinal cord grey matter divided into
the first most ventral part: motor area, the second autonomic functions area (balance) and the lastly most dorsal sensory part consisting of grey matter.
The most dorsal white matter part of the spinal cord
Consists of Dorsal funiculus/columns and is divided into a lateral part called the cuneate fasciculus and a medial gracile fasiculus that carries discriminative info.
The lateral funiculus on the most lateral side of the spinal cord
located below ventral funiculus consists of motor columns of white matter
Ventral funiculus
located at the most ventral side of the spinal cord and consists of white matter controlling pain and temp.
Nucleus proprius
where the second route of the discriminative information neuron fibers head towards located in the sensory part of the grey matter in the spinal cord.
In the spinal cord where does the myelinated pseudo uni polar neuron go?
enters the dorsal root and has a cell body in the enlargement, the fibre goes two either two different routes, straight to the dorsal columns on a homonculuar map or to nucleus proprius for discriminate sensation info. Fibers synapse there and goes back to the dorsal columns in a method for convergence.
Where does the unmyelinated free nerve ending go?
Heads into the dorsal root with a cell body in the enlargement, the fibers head towards the lowermost part of the sensory area of grey matter in the spinal cord called the substantia gelatinosa, synapses to a nerve that CROSSES over to the ventral funiculus for pain and temp.
Substantia gelatinosa
transparent area in the sensory area of grey matter in the spinal cord, transparent for unmyelinated nerves.
What is the area where the white matter crosses over in the indiscriminate nerve track
ventral/anterior white commisure.
Difference between the discriminate and indiscriminate info track
indiscriminate info crosses over to the other segmental side in the spinal cord whereas discriminate stays on the same side.
Brown sequard syndrome
a lesion at on side of the neuron carrying information (eg right), therefore cannot feel discriminate info on the right and indiscriminate info on the left and left side non discriminate info crosses over.
Lesion of one side of the brain stem (eg right)
Associative sensory loss, both associated to C8 lost on the specific side while the other side remains unaffected.
Conduction speed of non discriminate info
not myelinated at 1 m/s (slow)
What is the conduction speed for discriminate info
heavily myelinated at 50 m/s (fast)
Function of non discriminative info
pain and temp sensation info (nociception)
Function of discriminative info
Touch and pressure sensation info (proprioception)
Where does the first neuron terminate in discriminate info
dorsal column nuclei, either gracile or cuneate nucleus
Where does the first neuron terminate in non discriminate info
ventral horn substantia gelatinosa
where does the discriminate info decussate
internal arcuate fibers in the lower medulla.
where does the non - discriminate info decussate (cross over)
anterior white commisure
Basal ganglia
A large group of neurons (ganglia) Consists of five distinct nuclei that coordinates smooth movements such as mood and expression of mood (smooth movement control) that carries information for the planning of motor movement.
The first and second nucleus of the basal ganglia
The caudate nucleus and the putamen which make up the striatum and acts like one nucleus. They are connected by fibers.
The third nucleus of the basal ganglia
globus paladius which consists of two segments, the internus (closest to the thalamus) and the externus.
The forth nucleus of the basal ganglia
subthalamic nucleus directly under the thalamus
the last nucleus of the basal ganglia
substantia nigra (under the subthalamic nucleus and in the mid brain). Responsible for 90% of the dopamine produced in the brain.
Monosynaptic reflex
a fast reflex that activates opposite set of muscles to move quickly. Enters the dorsal root to the dorsal motor columns and synapses to a lower motor neuron in the grey matter and goes out the ventral root to contract muscles.
Lateral corticospinal tract
makes up of around 85% of the crossed over fibers and allows smooth movement control near the spinal cord.
what happens when there is a lesion in the upper motor neuron tract
spastic paralysis (stiffness and rigidity) due to the lack of lower motor neuron control due to disconnection from high level control to LMN.
Pyramidial decussation
80% fibers cross over at this point of the corticospinal tract.
Parkinsons disease
Where the substantia nigra cells are affected -> lower dopamine -> more toxic glutamate -> striatum nerves affected -> parkinsons -> flat face, slow activation of muscle and stiffness + rigidity.
What happens when there is a lesion in the lower motor neuron
Flaccid paralysis as there is no muscle control or LMN to allow contraction of the muscle.
Hypoactivity/ hypoexcitability
Inhibitors in striatum affected -> inhibitor to thalamus fires constantly and affects glutamatergic neuron to the cerebral cortex -> hypo excitability/activity.
corpuscle for touch
meissners corpuscle
Sensory nerves
known as afferent nerves bring sense info into nervous systems
CNS organs
brain and spinal cord
PNS
cranial nerves, spinal nerves, peripheral nerves and ganglia
What is the corpuscle for pressure
pacinians corpuscle
Motor neurons
efferent neurons
Neurons cell structure
consists of a cell body with dendrites and thin long extensions of the cytoplasm being the axon covered in myelin sheath and branching out into axon terminals.
Somatic control
voluntary control with the skeletal muscle.
Autonomic control
involuntary control and can be divided into sympathetic or parasympathetic which controls the cardiac muscle, smooth muscle and glands. Controls body’s internal responses.
Myelinated nerve structure
axon in the center, covered by a myelin sheath and a Schwann cell that contains a membrane that has a protein called myelin.
unmyelinated nerve structure
consists of axons and also Schwann cells but no wrapping of myelin (insulated later).
The nerve component attaching synapsing on another to send information.
presynaptic neuron
The nerve component receiving information from a nerve synapse
postsynaptic neuron
the gap inbetween two synapsing nerves
gap-synaptic cleft
sympathetic division associated with
exercise, emotion and excitement.