Chapter 12 part 1) CNS Flashcards
(45 cards)
1
Q
Cephalization
A
- Development of the Anterior poriton of the CNS
- Results in increased nueron numbers
- Highest level of nuerons reached in Brain
2
Q
Brain Development (steps)
A
- Brain and Spinal chord begin as the Nueral Tube
- Nueral Tube Expands and constricts to from Three Primary Vessicles
- Prosencephalon) or Forebrain
- Mesencephalon) Midbrain
- Rombencephalon) Hindbrain
- Primary Vessicles become secondary vessicles
- Forebrain) Becomes Telencephalon and Diencephalon
- Telecephalon) Forms cerebral hemisphieres (Cerebrum)
- Diencephalon) Becomes epithalamus, thalamus, hypothalamus, and retina.
- Midbrain) Remains as the Mesencephalon
- Hindbrain) Becomes metencephalon and myelencephalon
- Menencephalon) becomes pons and cerbellum
- Myelencephalon) Becomes medulla oblongata
- Central Cavity) becomes the ventricles.
- Forebrain) Becomes Telencephalon and Diencephalon
3
Q
Why Does brain fold?
A
Spinal chord develops slower than the Brain. Folds are there to save space.
- Forebrain moves toward brainstem and crease/ fold while doing so.
4
Q
Brain Regions (four)
A
- Cerebral Hemispheres
- Diencephalon
- Brainstem (Midbrain, Pons, Medulla)
- Cerebellum
5
Q
White and Grey Matter
(Definition and Location)
A
- Grey matter) short, unmylinated nuersons and cell bodies.
- White Matter) Mylinated. Some axons are unmyelinated.
- Basic Pattern In CNS) Grey matter covers the outside of the brain. Inside of brain is made of white matter.
- Cerebrum and Cerebellum have scattered areas of grey matter called nuclei.
6
Q
Ventricles
A
- Ventricles) Fluid-Filled chambers that are continuous to one another
- Filled with cerebrospinal fluid (CSF), lined by ependymal cells.
- Four Major Ventricles
- Paried Lateral Ventricles) Large C-shaped chambers located in each hemisphere
- Seperated by membranous septum pellucidum.
- Connected to third ventricle via interventricular foramen
- Third Ventircle) Lies in Diencephalon
- Connected to fourth ventricle via cerebral aquaduct.
- Fourth Ventricle) Lies in Hindbrain. Continuous with spinal chord.
- Paired Lateral Apertures and Median Aperture connect fourth ventricle to subarachnoid space (surrounds brian)
- Paried Lateral Ventricles) Large C-shaped chambers located in each hemisphere
7
Q
Cerebral Hemispheres
A
- Cerebral Hemispheres) form superior part of the brain.
- Account for most (83%) of brain mass
- Gyri) ridges on surface of brain
- Sulci) Shallow grooves
- Central Suculus) Seperates Precentral and Postcentral Gyrus of parietal lobe
- Parieto-Occupital Sulus) seperates occipital and parietal lobes
- Lateral sulcus) outlines temporal lobe
- Fissures) Deep grooves.
- Longitudinal Fissure) Seperates two hemisphieres
- Transverse Cerebral Fissure) Seperates Cerebrum and Cerebellum
- Suculi Divide each hemisphere into five lobes
- Frontal
- Parital
- Temporal
- Occipital
- Insula) burried deep within laterl sulcus.
8
Q
Cerebral Cortex
A
- Enables awarness and voluntrary movments,
- Thin, superfical layer of grey matter
- Made of nueron cell bodies, dendrited and glial cells and blood vessels (no Axons)
- 40% of brain mass
9
Q
Four Considerations of Cerebral Cortex
A
- Made of three functional areas
- Motor Areas) control voluntray movment
- Sensory areas) conscious awareness of
sensation - Association areas) integrate diverse information
- Each hemisphere is concerned with colateral (opposite) side of body
- While symmetrical in structure, the two hemispheres are not equal in function. They are laterally specialized and some functions can only appear in one hemisphere.
- No Functional are of the cortex acts alone.
- Behivior involves entire cortex in one way another.
10
Q
Motor Areas
A
- Located in frontal lobe, motor areas act to control voluntary movement
- Primary motor cortex) in precentral gyrus
- Premotor cortex) anterior to precentral gyrus
- Broca’s area) anterior to inferior premotor area
- Frontal eye field) within and anterior to premotor cortex; superior to Broca’s area
11
Q
Primary (somatic) Motor cortex
A
- Located in precentral gyrus of frontal lobe
- Pyamidal Cells) Large nuerons that allow conscious control of percise, skilled, skeletal muscle movnebts
- Pyramidal (cortico spinal tracts) Formed by axons of pyramidal cells that project down spinal chord.
- Somatotopy) Mapping all muscles back to their control center on primary motor cortex)
12
Q
Premotor Cortex
A
- Helps plan movments. Selects and sequnces basic tasks into more complex tasks
- Uses processed sensory information to make more informed descisions
13
Q
Brocas Area
A
- Only found in one hemisphere (usually left)
- Directs the muscles of speech production
14
Q
Frontal Eye Field
A
- Controls Voluntary Eye movments.
15
Q
Homestatic Imbalance To Motor Cortex
A
- Primary Motor Cortex) paralyzes muscles controled by that area
- Paralysis occurs on opposite side of the body than damage.
- Only voluntary control is lost
- Premotor Cortex) Loss of moter skills programed by that area, but does not impair muscle movments.
16
Q
Sensory Areas
A
- Sensory areas) Areas of cortex concerned with conscious awareness of sensation
- Occur in parietal, insular, temporal, and occipital lobes
- Eight main areas include
- primary somatosensory cortex,
- somatosensory association cortex
- visual areas
- auditory areas
- vestibular cortex
- olfactory cortex
- gustatory cortex
- visceral sensory area
17
Q
Primary Somatosensory Cortex
A
- Located in postcentral gyri of parietal lobe
- Recives sensory information from skin, muscles, joints and tendons.
- Spatial Dicrimination) Identificaton of body part being stimulated.
18
Q
Somatosensory association cortex
A
19
Q
- *
A
- Posterior to primary somatoseneory cortex
- Integrates sensory input from primary somatosensory cortex for understanding of object.
- Determines size, texture, and relationship of parts of objects being felt.
20
Q
Viusual Areas
A
- Primary Visual Cortex) Located on posterior tip of occipital lobe
- gets information directly from ritenias
- Visual association area) Surrounds primary visual cortex (all association areas are next to their primary cortex)
- Uses past visual expirences to interpret information
- EX) reconizing someones face
- This complex process inciles enrite posterior half of cerebral hemispheres.
21
Q
Auditory Areas
A
- Primary Auditory Cortex)
- Superior Margin of temproal lobes
- Interpretes information directly from ear
- Auditory Association area
- Located posterior to primary auidtory cortex (all association areas are next to their primary cortex)
- Stores memory of sounda and permits perception of sounds
22
Q
Vestibular Cortex
A
- Part of Insula and adjacent parietal cortex
- Responsible for councious awareness of balance.
23
Q
Olfactory Cortex
A
- Primary Olfactory Cortex
- Medial aspect of temoral lobes
- Part of Rihencephalon
- all parts of cerebrum that recive olfactory signals.
- During evolution, Rhinrncephalon changed and now functions in emotion and memory
- Involved in conscious awarness of odors.
24
Q
Gustatory Cortex
A
- Located in Insula Deep to Parietal Lobe
- Involved in perception of taste
25
Visceral Sensory Area
* Posterior to gustatory cortex
* Conscious perception of visceral (organ) sensations
* such as upset stomach or full bladder.
26
Multimodal Associaton Areas
* Receive inputs from multiple sensory areas and send outputs to mutiple areas.
* Sensations, Throughts, and Emotions make us who we are
* Allow us to store infomation in memory, tie to previous info, and decide actions.
* Divided into three parts
* Anterior Association Area (prefronatal cortex)
* Posterior Association area
* Limbic association area
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Anterior Association Area (prefrontal cortex)
* Most complicated cortical region. Involved with intelect, cognition, recall and personality.
* Contains memory needed for abstract thinking, judgment and reasoning, and planning.
* Development depends on feedback from social environment.
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Pathway of Information
Sensory Receptors ⇒ Primary Sensory Cortex ⇒ Sensory Association Cortex ⇒ Multimodal Association Cortex.
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Psoterior Association Area
* Large region in temproal, parietal, and occitital lobes
* Playes role in reconizing patterns and faces. Also localizes us in space
* Understanding of Written and Spoken Language
* area called Wernicke's Area
30
Limbic Association Area
* Part of the limbic system
* Involves hippocampus and more
* Provides emotional impact that makes a scene important to us and helps establish memories.
31
Lateralization of Cortical Function
* Lateralization) Division of Labor between two hemispheres of brain.
* Hemispheres are not identical.
* Cerebral Dominance) Refers to the hemisphere that is dominate for language.
* 90% of humans are left side dominant
* Other 10% roles of hemispheres are reversed
* Left Hemisphere) Language, Math, and Logic
* Right Hemishere) Visual-spatial skills, Intuition, emotion and artistic skills.
* Ambidextrous) Cerebral Cortex functions bilaterally.
32
White Matter and Fibers
* Responsible for Communication between cerebral areas and cortex and lower CNS
* Consists of mylinated Fibers bundled into large tracts
* Association Fibers) Horizontial fibers that connect diffrent parts of same hemisphere
* Commissural Fibers) Horizontal fibers which connect grey matter of two hemispheres
* Largest is Corpus collosum which is superior to lateral Ventricles
* Projection Fibers) Vertical fibers that connect brian to lower spinal chord (Cortex and Lower CNS)
33
Basal Nuclei (Basal Genflia)
* Deep within white matter
* Funtions
* Influence movment
* Plays role in cognition and emotion
* Important in in starting or stoping repatitive movments
* Such as arms swinging when running
* Filter responses
* Inhibit Unnessary muscle movment
* Parkinsons/ Huntinton's are disprders of the basal nuclei.
34
Diecephalon
* Consists of three paired grey-matter structures
* Thalamus
* Hypothalamus
* Epithalamus
* All three enclose third ventricle.
35
Thalamus
* Makes up 80% of the Diencephalon
* Made of two Bilateral nuclei
* Connected by interthalamic adhesion (intermediate mass)
* Each side contains several Nuclei. These project and recive fibers from cortex
* Funtion) Relay station for information coming into cortex
* Sorts, edits and ealays input such as impusles.
* Acts to mediate sensation, motor activities, cortical arousal, learning and memory.
36
Hypothalamus
* Located below thalamus
* Forms infero-lateral walls of third ventricle
* (Beak of the Turkey)
* Main Center for control of Visceral (organ) homestasis,
* Important Nuclei in Hypothalamus
* Mammillary bodies) Olfactory Relay station
* Infundibulum) Connects to petuitary gland
* Funtions
* Control Autonomoc Nervous system) Blood Pressure, heartrate, digestive tract mobility.
* Physical responses to emotion) Precives pleasure, fear, rage, bilogical rythams and drives
* Regulation) Body Temp (shivering/ Sweating), Hunger levels, Water Levels, Sleep-wake cycles.
* Controls some Endocirne system functions
37
Hypothalamic Homoeostatic Imbalance
* Hypothalamic disturbances cause a number of disorders such as:
* Severe body wasting
* Obesity
* Sleep disturbances
* Dehydration
* Emotional imbalances
* Can be damaged by tumors, radiation, surgery or trauma
38
Epithalamus
* Most Dorsal Portion of Diencephalon; Forms roof of third Ventitcle
* Contains the Pienal Gland
* Secretes metatonin.
39
Brain Stem
* Consists of three regions
* Midbrain, Pons, and the Medulla Oblongata
* Similar in Structure to Spinal Chord but has nuclei imbedded in white matter
* Controls automatic behiviors nessessary for survival
* Contains Fiber Tracts
* Cnnect higher and lowe nural centers
40
Midbrain
* Between Diencaphalon and Pons
* Cerebral Aquaduct) Channel Running through midbrain
* Connects third and fourth ventricles
* Midbrain Nuclei) scattered throuought white matter
* Corpora Quadrigemina) paired dorsal protrusions
* Superior Colliucli) Visual reflex center
* Inferior Collicili) Auditory relay center
* Substantia Nigra) Linked to basal nuclei
* Parkinson's affects this area
* Red Nucleus) Relay nuclei for some descenting limb motor pathways
41
Pons
* Located Beteen Midbrain and Medulla Oblongata
* Fourth Ventricle seperates pons from cerebellum
* Conduction Tracts
* Longitudial Fibers) conenct higher brain center and spinal chord
* Transverasl/Dorsal Fibers) Relay impulses between motor cortex and Cerebellum.
* Origin of some cranial nerves
42
Medula Oblongata
* Joins Spinal Chord at Froamen Magnum, Forms part of ventral wall of fourth venrricle.
* Chorid Plexus) Membrane that forms cerebral spinal fluid.
* Structures in Medula Oblongata
* Pyramids) Two Ventral ridges formed by pyrmidal tracts from Motor Cortex
* Decussation of the Pyrmaids) point where tracts cross to other side of body. Creates Laterlization
* Funtions
* Autonmoic Reflex Center. Hypothalamus relays info via medula.
* Functional Groups
* Cardivascular center) moniters heart rate and blood pressure
* Respritory Center) Respritory Rytem and breathing rate
* Other Centers) vomiting, hiccupping, Swalloing, Coughing and Sneezing.
43
Cerebellum
* Doral to pons and medulla
* Procrsses Imput from Cortex, Brain Stem, and Sensory Receprors to provide precise, coordinated movments. Also has major role in balance
44
Anatomy of Cerebellum
* Vermis) Hemispheres connected by the Vermis
* Folia) Transversely orientated gyri
* Each Hemisphere has three lobes
* Anterior
* Posterior
* Floccunlondular
* Arbor Vitae) Thin Cortex of grey matter with treelike pattern.
* Cerebellar Puncidcles) Fiber Tracts which connect cerebellum to brainstem
* Superior Cerebellar Peduncles) Cerebellum to Midbrain
* Middle Cerebellar Peduncles) Cerebellum to Pons
* Inferior Cerebellar Peduncles) Cerebellum to Medulla
45
Cerebellar Processinf of Motor Acticity
1. Recives imules from cerebral cotrex to cause muscle contraction
2. Recives signals from propioceptiors throught the body
* Informs cerebellum of body position (proprioception)
3. Calculates best way to smoothly coordinate contractoion
4. Sends "Blueprint" of movment to motor cotex and brain stem
