Anat Final
Frontal Lobe: Motor Cortices- Primary motor cortex is located and responsible for and AKA?
(anterior to central gyrus): Voluntary motor activity - AKA precentral gyrus, BA 4 Beginning of the corticospinal tract - Innervation can be diagrammed as a motor homunculus on the precentral gyrus
Brodmann's Areas
(shorthand BA refers to these areas) German anatomist Korbinain Brodmann, 1909 - Created the map by based on cytoarchitectural differences in different brain regions - Areas numbered 1-52
How much cerebrospinal fluid is present at any one time? - A. less than 50 mL - B. 100-200 mL - C. 500-600 mL - D. More than 1000 mL
- B. 100-200 mL
Sulci help divide the lobes of the cerebrum, what are their names? And what do they divide?
- Central Sulcus- separates parietal from frontal lobe - Lateral (Sylvian) fissure (sulcus)- separates parietal and frontal from temporal - Parieto-occipital sulcus- separates parietal and occipital lobes
BBB Missing or reduced in 3 distinct locations in the CNS:
- Choroid plexus - Hypothalamus - Pineal gland
2 cerebral hemispheres only connected by a few white matter pathways, what are they?
- Corpus callosum- majority of fibers - Anterior commissure- connect parts of temporal and frontal lobe Posterior commissure
Cranial Meninges Functions:
- Covers and protects brain - Protect from foreign substances - Encloses and protects vessels supplying to brain - Acts as an anchor for the brain to the skull - Contains CSF
Cerebrospinal fluid passes through choroidal villi to enter the superior sagittal sinus. - True - False
- False
Wernicke's Aphasia
- Fluent speech Impaired retention and comprehension - Wordy but meaningless speech Can speak w/o a problem but what you say doesn't make sense **People are NOT aware that they have this problem
Four functions of the cerebrospinal fluid.
- Hormone transport - Buoyancy - Protection - Environmental stability
Temporal lobe- location, gyri names, involved with?
- Inferior to lateral sulcus Superior, middle, & inferior gyri - Involved with hearing and smell Medial temporal lobe structures are associated with the limbic system - Memory, learning, aggression, emotion
Parietal Lobe: Somatosensory Cortices- Primary somatosensory cortex- is located and responsible for and AKA?
- Receives general somatic sensory info from touch pressure receptors - Postcentral gyrus, BA 3, 1, 2 Beginning of dorsal column-medial lemniscus tract here (DCML) - Sensory homunculus***- some parts of body that have no need for motor function are shown here but rest is pretty similarly mapped out
Dural venous sinuses:
- Superior sagittal sinus Largest sinus- in superior midline - Inferior sagittal sinus Drains blood from center of brain - Transverse sinuses L & R lateral drain from back of head - Occipital sinus Goes along with occipital region (base of skull)- smallest of sinuses--(normally only 1 but can see 2 sometimes)
How are the right and left cerebral hemispheres specialized for different functions? - The right cerebral hemisphere is primarily involved with intuition, emotion, math skills, and logic. - The right cerebral hemisphere has more control over logical reasoning. - The left cerebral hemisphere has greater control over math and language. - The left cerebral hemisphere directs musical and artistic abilities, visual-spatial skills, and the ability to read facial expressions.
- The left cerebral hemisphere has greater control over math and language.
Why is hydrocephalus much more serious in adults than it is in infants?
- The skull is not fully fused until age 2 so the skull is able to enlarge with excess fluid. - In adults cranial bones are fused and there is danger of the increased pressure crushing the brain in adults.
Arachnoid Mater
- Thin, avascular membrane - Semitransparent (vs. dura that is much more white and opaque)
The meninges of the brain differ from those of the spinal cord in that the dura mater of the brain splits into two layers and that there is no epidural space. - True - False
- True
It is easy to confuse the terms sulcus and gyrus (on the cerebral cortex). The difference between these two terms is that - a sulcus corresponds to a folia on the cerebellum, whereas a gyrus corresponds to a fissure. - a sulcus is a groove, and a gyrus is a deeper groove. - a sulcus is the same as a fissure on the cerebral cortex, whereas a gyrus is a lobe. - a gyrus is a ridge, and a sulcus is a groove.
- a gyrus is a ridge, and a sulcus is a groove.
The subarachnoid space lies between what two layers of meninges? - arachnoid and bone of skull - arachnoid and pia - dura and epidura - arachnoid and dura
- arachnoid and pia
All of the following are structures of the limbic system except the - cingulate gyrus. - caudate nucleus. - amygdaloid nucleus. - hippocampus.
- caudate nucleus.
Cerebrospinal fluid is produced by choroid plexuses in all the following locations except the - lateral ventricle. - fourth ventricle. - central canal. - third ventricle.
- central canal.
Trace the path of circulation of cerebral spinal fluid (CSF) from production to absorption. - Third ventricle, fourth ventricle, central canal of spinal cord, lateral and median apertures - arachnoid villi, ventricles of the brain, subarachnoid space, choroid plexus, superior sagittal sinus - ventricles of the brain, choroid plexus, arachnoid villi, subarachnoid space - choroid plexus, ventricles of the brain, subarachnoid space, arachnoid villi, superior sagittal sinus
- choroid plexus, ventricles of the brain, subarachnoid space, arachnoid villi, superior sagittal sinus
The tough, dense fibrous connective tissue meningeal layer is the - dura mater. - subarachnoid. - arachnoid. - pia mater.
- dura mater.
The sheet of dura mater that separates the right and left cerebral hemispheres is the - tentorium cerebri. - superior sagittal sinus. - falx cerebri. - falx cerebelli.
- falx cerebri.
Areas of the cerebral cortex involved with the initiation of motor impulses are localized to the posterior aspect of the __________. - temporal lobe - insula - frontal lobe - parietal lobe - occipital lobe
- frontal lobe
Which of these lobes of the cerebrum lies anterior to the central sulcus? - cerebellum - temporal lobe - frontal lobe - occipital lobe
- frontal lobe
The abstract representation of the homunculus overlaid on the somatosensory cerebral cortex has the - genitals proximal to the longitudinal fissure. - feet and ankles distal to the longitudinal fissure. - thumbs and fingers proximal to the longitudinal fissure. - head and face proximal to the longitudinal fissure
- genitals proximal to the longitudinal fissure.
The function of the blood-brain barrier is to - keep neurons from innervating blood vessels. - provide an impenetrable barrier between blood and brain, because the brain gets all its nourishment from the cerebrospinal fluid. - prevent all contact between bloodborne molecules and brain tissue. - help protect the central nervous system.
- help protect the central nervous system.
Cerebrospinal fluid (CSF) __________. - has the same chemical composition as blood plasma - is an effective barrier against all poisons and drugs - is formed in the choroid plexuses of all four brain ventricles - has more protein and less sodium and chloride ions than blood plasma - All of the listed responses are correct.
- is formed in the choroid plexuses of all four brain ventricles
The only one of the meninges that follows the brain surface into a cerebral sulcus is the - alma mater. - dura mater. - arachnoid mater. - pia mater.
- pia mater.
Cerebrospinal fluid is located within the - orbits. - cerebral cortex. - subarachnoid space. - superior sagittal sinus.
- subarachnoid space.
A shallow groove on the surface of the cerebral cortex is called a - furrow. - sulcus. - fissure. - gyrus.
- sulcus.
Which of the following grooves separates the cerebrum from the cerebellum? - transverse cerebral fissure - lateral sulcus - central sulcus - longitudinal fissure
- transverse cerebral fissure
Left vs. Right Hemisphere- Right Hemisphere
- visuospatial functions= BIG Integrating lots of pieces from dif senses (create a whole) - Art and music abilities= big** - All motor and sensory info from Left side
A "motor homunculus" can be visualized as an overlay on the precentral gyrus. The reason why the facial region of this homunculus covers such a large surface area is because - our ears are large for hearing. - we have very sensitive lips. - our eyes are large for seeing. - we have very expressive faces.
- we have very expressive faces.
Subarachnoid space
--Arachnoid trabeculae- help anchor arachnoid mater to brain Weblike threads (spider-like) Extend from arachnoid to pia mater - Cerebrospinal fluid- travel with space - Blood vessels- lots of them- BUT not well protected b/c layer is thin & elastic
Four things that provide support and/or protection to the brain.
1- Bony cranium (skull) 2- Protective CT (meninges) 3- CSF 4- Blood-brain barrier
Cranial Dural Reflections (Septa)- 3 of them
1- Falx cerebri- b/w 2 cerebral lobes of the brain 2- Falx cerebelli- b/w 2 cerebellum halves 3- Tentorium cerebelli- runs b/w cerebellum and cerebral hemispheres **Named by where they are located
Support and Protection of the Brain
1. Bony cranium- (skull) protects brain 2. Protective connective tissue (meninges) 3. Cerebral spinal (Cerebrospinal) fluid 4. Blood-Brain barrier
Cranial Meninges--3 CT layers surrounding the brain
1. Dura mater (outermost) 2. Arachnoid mater 3. Pia mater (innermost)
4 Ventricles of the brain- and they all contain what?
2 lateral ventricles- Septum pellucidum (thin membrane that separates the 2 ventricles) 3rd ventricle- Interventricular foramen (of Monro) Cerebral aqueduct 4th ventricle- drains to brainstem - Lies in brainstem dorsal to pons, superior half of medulla oblongata) - Paired lateral and median apertures ***ALL Contain the choroid plexus- produces CSF - Found in each ventricle, 1 in each cerebral hemisphere
Orientation in the CNS- Afferent/Efferent
Afferent- incoming sensory info Efferent- outgoing motor info
Three things found in the subarachnoid space.
Blood vessels CSF Arachnoid trabeculae
Capillary endothelial cells and astrocyte perivascular feet contribute to BBB- what do they do?
Capillary endothelial cells (reg. What is going on) and astrocyte perivascular feet (deliver things through barrier-ex. Deliver nutrients, BUT allow some toxins- ex. Alcohol & nicotine) contribute to it
Left vs. Right Hemisphere- Left Hemisphere
Categorical hemisphere - Speech Sequential and analytical reasoning tasks - Partitioning information into smaller fragments for analysis - Language= huge here** Math --All motor and sensory info from Right side
What cavity connects the third and fourth ventricles?
Cerebral aqueduct
Orientation in the CNS-
Contralateral- opposite side Ipsilateral- same side (**Proximal/Distal generally not used in head and neck)
Arachnoid barrier
Contributes to blood-brain barrier - Outermost cells of layer don't allow fluid outside to enter brain, help to act as cushion barrier
Cytoarchitecture
Depending on function of brain, layers look different **6 layers of cerebrum cortex Some parts are darker and lighter, others are thicker and thinner
Tough, pain-sensitive layer that encloses the brain.
Dura mater
Circulation of CSF pathway
Ependymal cells 1. Lateral ventricles---interventricular foramen (of Monro)--3rd ventricle 2. 3rd ventricle---cerebral aqueduct---4th ventricle 3. 4th ventricle--paired lateral apertures or the single median aperture--subarachnoid space OR 4th ventricle--central canal of the spinal cord 4. Excess CSF flows into the arachnoid villi, then drains into the dural venous sinuses
Dorsolateral prefrontal cortex is responsible for what?
Executive functions Organization and planning Managing behavior High-level decision-making Multitasking Working memory (ex. Remembering a phone # just long enough)
Fissure vs. Gyri vs. Sulcus
Fissure- a deep sulcus Gyri- ridges Sulci- grooves **All of twisting and folding allows for increased SA (increases surface area about 3X) allows for more complex thinking
Functions of CSF
Functions: - Buoyancy- prevents brain from being crushed by own weight - Protection- liquid cushion & buffer - Environmental stability- transport nutrients, removes wastes - Hormone transport
Gray Matter and White Matter in the brain, what are they and where are they located?
Gray matter= cell bodies** (majority), dendrites, unmyelinated axons - Cortex: covers the surface of the brain (majority of gray matter is here b/c sends and receives signals from lower CNS) - Forms discrete internal clusters called cerebral nuclei White matter= myelinated axons
Divisions of the Brain- as it develops, has how many parts and what are they?
Has 5 parts - Telencephalon- cerebrum (largest portion) - Diencephalon- hypothalamus, thalamus, epithalamus - Mesencephalon- midbrain (most superior brain stem - Metencephalon- pons & cerebellum ("Meet" here) - Myelencephalon- medulla oblongata
Cranial Dural Reflections (Septa) functions
Help provide support and stabilization Divides to smaller subdivisions - Limits movement of brain in the cranium
Motor homunculus diagrams what?
Innervation of precentral gyrus - Face= big on map b/c so expressive Hands= big on map b/c smaller finer movements (Know motor map in precentral gyrus b/c have different blood supplies)
What feature connects each lateral ventricle to the third ventricle?
Interventricular foramen
Frontal Lobe: Motor Speech Area only in what hemisphere?
Left
Cerebral cortex is where cognition occurs
Mental processes such as awareness, knowledge, memory, perception, problem solving, decision making, information processing, and thinking **All comes from integration from different regions of the brain
Cerebral Hemispheres are Anatomically mirror what? but differ in what way?
Mirror images, but differ functionally
Orbitofrontal cortex is responsible for what?
Modulating emotions Inhibition Adaptive learning, rewards, and emotion
Anterior Cingulate Cortex is responsible for what?
Motivational behavior Reward-based learning **Error detection- more of this Outcome monitoring- was the outcome what you wanted? **Pain processing- sets apart from other cortexes
Two layers that make up the dura mater.
Outer periosteal layer Inner meningeal layer
Somatosensory association cortex
Part of parietal lobe that Integrates and interprets sensory information
Broca's aphasia
Patient can understand spoken language but has difficulty communicating verbally Have a hard time with output ****People know they have this problem and find it very frustrating (may not be able to write or sign language, but varies)
What part of our brain sets us apart from different animals?
Prefrontal cortex-way more developed
Central white matter- 3 tracts and where are they located
Primarily myelinated axons bundled into tracts - Commissures: tracts from R to L hemispheres (across hemispheres) - Association fibers: go from 1 part of brain to the other (connects 2 parts of the brain) - Projection fibers: run vertically, fibers going from brain to spinal cord
Premotor cortex and supplementary motor cortices do what?
Process motor information, plans and coordinates learned, skilled motor activities
History Fact: Phineas Gage Case
Railroad worker was well-liked - Had a pole go through his skull and prefrontal cortex--changed his personality and behavior
Wernicke's Area
Recognizing and comprehending written and spoken language - Within left hemisphere, overlaps the parietal and temporal lobes
Orientation in the CNS- Rostral/Caudal
Rostral (toward nose)/Caudal (toward tail)
What is the name of the membrane that separates the two lateral ventricles?
Septum pellucidum
Arachnoid granulations (arachnoid villi)
Superior part of brain - Knoblike projections - Act as valves- allow CSF to pass from arachnoid to dural space
Parietal lobe
Superoposterior part of each hemisphere - Central sulcus anteriorly - Lateral sulcus inferiorly Parieto-occipital sulcus posteriorly - Involved with general sensory functions (major function): tactile sensation, proprioception, taste, language, spatial orientation, and directing attention
Cerebrum what is it and what division of the brain is it part of? The twisted structure of the cerebrum allows for what?
Telencephalon--biggest part - contains a large # of neurons needed for complex analytical and integrative functions (senses, personality, control movement) - Contains many sulci and gyri **All of twisting and folding allows for increased SA (increases surface area about 3X) allows for more complex thinking
Regions of the Head and Neck- temporal, zygomatic, auricular, occipital, mental regions
Temporal region- by temple Zygomatic region- apple of cheek Auricular region- by ears Occipital region- toward base of skull mental region- chin
Hemispheric Lateralization what is it highly correlated with?
The cerebral hemispheres are specialized for certain functions - Hemispheres control contralateral sides of the body - Highly correlated with handedness*** Right handed people have different lateralization patterns than Left handed people (Right controls left and vice versa)
Orientation in the CNS- Ventral/Dorsal
Ventral (under side of brain)/Dorsal (top half of brain) - anterior/posterior - superior/inferior
Frontal lobe- location in general and in relation to central and lateral sulci
anterior part of cerebral hemisphere - Central sulcus posteriorly - Lateral sulcus inferiorly Prefrontal cortex: anterior portion of frontal cortex
Epidural hematoma
b/w periosteal layer and skull - Can occur with a skull fracture of other trauma that damages the **meningeal artery -Very fast bleed **Often fatal unless treated quickly (otherwise will compress underlying brain) --(superior side of dura mater)
Subarachnoid Space is found where, what does it allow, and is considered what?
b/w the arachnoid and pia mater - Allows one-way flow of CSF out of arachnoid space - Filled with cerebrospinal fluid B/c of pressure differences- is mostly the ONLY SPACE found in the brain - CSF reabsorbed by arachnoid granulations
Hydrocephalus--what is it? And possible Causes of Hydrocephalus
blockage in CSF pathway but production continues (Usually treated by putting a shunt in brain) May be caused by: - Brain tumor, inflammatory swelling, meningitis - In infants, an overdeveloped choroid plexus can lead to too much CSF being produced
CSF production occurs where?
choroid plexus
Functional Areas of the Cerebral Cortex- MOTOR AREAS
control voluntary motor functions (skeletal motor)
Broca's area
controls muscle actions needed for speech - Inferolateral portion of left frontal lobe Important for actual physical production of speech
Median longitudinal fissure
divides the 2 cerebral hemispheres
Nervous tissue= very delicate- neurons don't
don't regenerate when damaged
Cerebrospinal fluid (CSF)-
filtrate of blood and returned daily - Colorless fluid that circulates in the ventricles and subarachnoid space
corpus callosum
major white matter tract that connects hemispheres of the brain - Connection b/w right and left hemispheres
Functional Areas of the Cerebral Cortex- Multimodal Association Areas
provide conscious awareness of sensation (every sense has its own individual primary sensory area)
Functional Areas of the Cerebral Cortex- Sensory areas
provide conscious awareness of sensation (every sense has its own individual primary sensory area)
Subdural hematoma
rapid acceleration or deceleration of the head - Tearing of a **cerebral vein as it pierces the arachnoid mater to enter a dural sinus - Slow bleed Some progress more quickly, others are slower - Start to compress underlying brain (under meningeal layer)
Function of blood-brain barrier
regulate what substances can enter the interstitial fluid of the brain
Sinuses are on the margins of
septa
How does Sensory homunculus differ from a motor homunculus?
some parts of body that have no need for motor function are shown here but rest is pretty similarly mapped out
Lobes of the Cerebrum- (4 lobes) what are they?
temporal, frontal, occipital, parietal
Dura mater- layer characteristics, # of layers, spaces?
thickest and toughest layer of the meninges --Pain-sensitive 2 layers of dense fibrous CT; tightly fused together except for dural venous sinuses - Outer periosteal layer- attaches inner surface of skull bones (is the periosteum) - Inner meningeal layer- forms the true external covering of the brain -next to arachnoid mater - Epidural space- above dura mater - Subdural space- b/w meningeal layer and arachnoid mater
Pia mater
thin (thinnest mater layer), delicate CT tightly apposed to the brain - Follows all contours of the gyri and sulci of brain - Highly vascularized with small blood vessels (very small) (Hard to see grossly b/c so thin and see through)
