Central Nervous System Flashcards
What are the four regions of the adult brain?
1) Cerebral Hemispheres
2) Diencephalon
3) Brain Stem
4) Cerebellum
What are the 5 lobes of the cerebrum?
1) Frontal lobe
2) Parietal lobe
3) Occipital lobe
4) Temporal lobe
5) Insula –> “bonus lobe” underneath temporal
What is the difference between gyri, sulci and fissures?
Gyri = ridges that stick out Sulci = shallow grooves Fissures = deep grooves
Which lobes does the Lateral sulcus split and what is another name for this?
Lateral sulcus splits apart the temporal lobe from the frontal and parietal lobe.
Also called the Sylvain fissure
What lobes does the transverse cerebral fissure split?
Separates the cerebellum from cerebrum
What does the Calcarine sulcus separate?
The Calcarine sulcus separates the primary visual cortex
What layers protect the brain? (5)
- SCALP
- Bone/Skull
- Blood-brain barrier
- Membranes/meninges
- Watery cushon/CSF
What does SCALP stand for?
S - skin C - connective tissue A - aponeurotic layer L - loose connective tissue P - Pericranium
What is the function of the blood-brain barrier?
1) maintains stable environment for the brain
2) acts as a metabolic barrier –> endothelial cells quickly metabolize anything coming in
Where is the blood-brain barrier not found?
Vomiting centre –> your body needs to know quickly if there is something it should get rid of
(area postrema)
Pituitary –> barrier would prevent release of hormones
How are brain capillaries different?
- they won’t let things move through them as easily because of tight junctions
- -> specifically lipid soluble
- more continuous
- insulated by astrocytes
What is the function of the meninges?
- cover and protect CNS
- forms the partitions in the skull
- protects blood vessels
- protects venous sinuses
- contains CSF
What are the two layers of dura mater?
1) Periosteal
2) Meningeal
What is the dura mater septa and what does it do?
What layers are there?
Dura mater septa are two layers of dura mater fused together that limit movement of the brain
You have:
- falx cerebri - separates cerebral hemispheres
- tentorium cerebelli - separates cerebrum from cerebellum like a “tent” over the cerebellum
- falx cerebelli - behind the cerebellum
What separates the dura mater from the arachnoid mater?
Subdural space - this is a potential space
What is the subarachnoid space?
- Contains CSF and blood vessels
- arachnoid villi stick into the superior sagittal sinus to reabsorb CSF
What are the functions of CSF? (4)
- Buoyancy to brain (like egg in water)
- Protect against trauma
- Nourishing, carries chemical signals
- Clears out waste
What does the chorioid plexus do and how?
Choroid plexus produces blood filtrate/CSF ~500mL per day
Choroid plexus is a meshwork of capillaries lined by endothelial cells –> lots of surface area to filter waste and pumps out things that we need (oxygen, glucose, water, and ions)
What type of cells line the choroid plexus and the ventricles?
Ependymal cells
How is CSF circulated through the ventricles?
choroid plexus makes the CSF within the ventricles so that they are filled with it, then it follows this sequence:
- lateral ventricles
- inter-ventricular foramen
- third ventricle
- cerebral aqueduct
- fourth ventricle
then exits through apertures and ends up in subarachnoid space
What is contained in the dural venous sinuses?
venous blood
*this is different from CSF because it also contains blood
What is the cerebral cortex?
Thin layer of superficial grey matter
What type of connection does the cerebral hemisphere have with the body?
Contralateral –> means that the right hemisphere is in control of the left side
What are the functional areas of the cerebral cortex?
- Motor areas
- Sensory areas
- Association area –> processes and integrates diverse information
What is the functional name of the pre-central gyrus and what does it do?
Primary motor cortex –> conscious control of precise and voluntary movements
What does somatotopic arrangement mean?
This refers to the map in the precentral gyrus/primary motor cortex that shows specific areas on the brain that control specific movements
What is the functional name of the frontal lobe anterior to the pre-central gyrus and what does it do?
Premotor cortex –> sends information to the primary motor cortex so that muscle groups can coordinate and perform sequential movements
also controls learned, repetitious or patterned motor skills
also plans movements depending on sensory feedback
What is the functional name of the part of the frontal lobe that is anterior to the inferior region of premotor area?
Broca’s area
What does Broca’s area do? Is it on one side of the brain?
- Controls motor speech and directs tongue muscles
- active when someone prepares to speak
Left side is dominant for language
–> right side controls sarcasm vs sincere communications, not considered part of the Broca’s area, this also does non-verbal communication
Where is the frontal eye field and what does it do?
Frontal eye field is superior to Broca’s area and it controls voluntary eye movements
What is the functional name of the post-central gyrus and what does it do?
Primary Somatosensory cortex –> receives information from the skin, skeletal muscles and joints (can discriminate between the regions of the body being touched)
–> it can tell that something is touching you and where, but not what it is
What is the functional name of the area posterior to the primary somatosensory cortex and what does it do?
Somatosensory association cortex –> integrates sensory information from primary somatosensory cortex
This can tell what is touching you (size, texture and relationship of parts of objects being felt)
What is the functional name of the posterior tip of the occipital lobe and what does it do?
Primary visual (striate) cortex –> receives the visual information from the retinas
What is the functional name of the area surrounding the primary visual cortex and what does it do?
Visual association area –> uses past visual experiences in order to tell what you’re seeing
In the visual association area, what streams are there?
Dorsal stream –> pathway that determines “where”
Ventral stream –> pathway that determines “what”
these pathways move towards the post-central gyrus, complex processing involves entire posterior half of the cerebral hemispheres
What is the functional name of the superior margin of the temporal lobe and what does it do?
Primary auditory cortex –> interprets information from inner ear as pitch, loudness and location
*does not necessarily know what it is
What is the functional name of the area posterior to the primary auditory cortex and what does it do?
Auditory association area –> stores memories of sounds and uses that to understand what the ears are hearing
*adding in meaning to what is being heard
What is the functional name of the medial aspect of the temporal lobes and what does it do? (Right beside hippocampus)
Olfactory cortex –> controls conscious awareness of smells
*right beside the hippocampus; reason why smells illicit memories so quickly
Where is the gustatory cortex and what does it do?
In the insular lobe (“bonus lobe”) –> involved in perception of taste
What area is found posterior to the gustatory cortex and what does it do?
Visceral sensory area –> conscious perception of visceral sensations
*not a lot of the cortex is devoted to this area so this is why we’re bad at knowing where pain is coming from in the visceral abdomen
What is a multimodal association cortex?
This is the part of the brain that sends information places using all of the integrated information from the association areas (that get information from the primary cortexes that get information from sensory areas)
What is the significance of the multimodal association cortex?
Allows us to attach meaning to information that is received, stores it as a memory, compares it to other experiences and decides on actions to take.
What are the three parts of the multimodal association cortex?
- Anterior association area (prefrontal cortex)
- Posterior association area
- Limbic system (deep)
What is the other name for the anterior association area and what does it do?
Prefrontal cortex –> involved in intellect, cognition, recall and personality, contains working memory that you need for judgement, persistence, and conscience
*this is the most complicated area in cortical region and develops slowly in children
Where is Wernicke’s area and what does it do?
Found in the posterior association area (a part of the multimodal association cortex) –> involved in understanding written and spoken language
What is prosopagnosia and what multimodal association cortex is it involved with?
Face blindness
Involved with the posterior association area which helps in recognizing patterns, faces and localizing ourselves in space
What does the limbic association area do?
Limbic association area is part of the multimodal association cortex –> lets us have emotional impact that helps establish memories
What is cerebral white matter and how are they characterized?
White matter are the myelinated fibers and their tracts. They are characterized by where they connect.
What fibers connect the gray matter of the cerebral hemispheres?
Commissural fibers –> found in corpus callosum
What fibers connect different parts of the same hemisphere?
Association fibers