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119 Cards in this Set
- Front
- Back
From what primary germ layer does all nervous tissue originate?
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Ectoderm
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Identify the adult brain structures associated with each of the three primary brain vesicles.
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- Prosencephalon (forebrain)
- Mesencephalon (midbrain ) - Rombencephalon (hindbrain) These are created when the anterior part of neural tube differentiates Remainder turns into spinal cord |
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What are the structural outcomes of the fact that the brain develops within a restricted space?
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1 - Midbrain and cervical flexures (they bend down)
2 - Posterior and lateral growth of the cerebral hemispheres (so that it completely encloses the brain stem) 3 - Surface convolutions (sulci and gyri); grooves increase surface area, pack more neurons into less space; fissures |
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Be able to describe the embryologic origins of the brain, beginning with formation of the neural plate.
- Make sure you look at notes - this card is not complete |
Ectoderm thickens forming neural plate
Neural tube invaginates, surrounded by edges (neural folds) and when they fuse = neural tube Off to the side there are 2 pinched off parts called neural crest (turns into part of PNS) Anterior neural tube - forms primary brain vesicles, which become secondary brain vesicles, which turn into adult brain structures; Central cavity (neurocoel) turns into 4 ventricles !!!see notes!!! |
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Neural Plate
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Thickened part of ectoderm that forms during the 3rd week
Origin of all neural tissue Invaginates to become neural tube |
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Neural tube
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The neural plate, once it is fully invaginated, and the neural folds fuse together
Filled with fluid - central cavity called neurocoel It's formation is called neurulation |
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Prosencephalon
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Primary brain vesicle (1 of 3) - the forebrain
Forms secondary vesicles - - telencephalon (will be cerebrum - cerebral hemispheres and basal ganglia) - diencephalon (epithalamus, thalamus, hypothalamus) |
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Mesencephalon
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Primary brain vesicle (1 of 3) - the midbrain
Does not subdivide into secondary brain vesicles Develops into midbrain (surrounds cerebral aqueduct) |
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Rhombencephalon
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Primary brain vesicle (1 of 3) - the hindbrain
Forms secondary vesicles - - Metencephalon (will become pons and cerebellum - houses part of 4th ventricle) - Myelencephalon (will becom medulla oblongata - houses remainder of 4th ventricle) |
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Telencephalon
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A secondary brain vesicle
Derived from Prosencephalon Becomes cerebrum (cerebral hemispheres and basal ganglia) |
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Diencephalon
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A secondary brain vesicle
Develops from Prosencephalon Becomes epithalamus, thalamus, hypothalamus (structures that surround the 3rd ventricle) |
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Metencephalon
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A secondary brain vesicle
Develops from Rhombencephalon Becomes pons and cerebellum (houses part of 4th ventricle) |
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Myelencephalon
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A secondary brain vesicle
Develops from Rhombencephalon Becomes medulla oblongata (houses remainder of 4th ventricle) |
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Spina bifada
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Failure to close of the posterior (caudal) neural tube
Usually not fatal |
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Anencephaly
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Failure to close of the anterior neural tube
Almost always fatal |
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Dura mater
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Protection and covering of the brain
Part of meninges Tough outer layer Where it surrounds the brain, made up of 2 layers - Superficial layer fused to periosteum on inner surface of cranial bones - Meningeal layer forms true external meninx of brain - continuous with dural sheath of spinal cord Usually fused together, when separate = dural sinuses that channel venous blood from brain to internal jugular veins in neck Extends in to make partitions to limit internal brain movement: falx cerebri, falx cerebelli and tentorium cerebelli |
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Pia mater
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Protection and covering of brain
Part of meninges Transparent inner layer which adheres to external surface of brain and cord |
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Cranial meninges
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- Dura mater (hard outer layer)
- Sub-dural space (beneath dura; film of fluid) - Arachnoid/arachnoid matter (middle layer) - Subarachnoid space (web like membrane extensions and Cerebrospinal fluid) - Pia mater (inner layer) |
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Arachnoid (or arachnoid matter)
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Part of meninges
Thin, transparant, middle layer |
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Falx cerebri
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Part of the dura mater (outer layer of meninges) when it extends inward to form partitions which limit brain movement in cranium
- dips into longitudinal fissure - attaches anteriorly to crista galli of ethmoid bone |
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Tentorium cerebelli
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Part of the dura mater (outer layer of meninges) when it extends inward to form partitions which limit brain movement in cranium
- extends into transverse fissure - separates and supports cerebrum and cerebellum |
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Falx cerebelli
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Part of the dura mater (outer layer of meninges) when it extends inward to form partitions which limit brain movement in cranium
- small midline partition that runs along the vermis of the cerebellum |
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Subarachnoid space
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Part of the cranial meninges
Surround and protect the brain Deep to the arachnoid, superficial to the pia mater Web like membrane extensions span it, connecting w/arachnoid and pia mater Space where CSF (cerebrospinal fluid) circulates completely around brain and spinal cord |
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Identify the ventricles of the brain and describe how they are connected.
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Lateral ventricles (paired) - C shaped, one in each hemisphere
Third ventricle - thin vertical slit in midline of diencephalon, communicates with fourth ventricle via cerebral aqueduct Fourth ventricle - between brain stem and cerebellum, continuous with central canal of spinal cord Lateral ventricles - interventricular foramen - third ventricle - cerebral aqueduct - fourth ventricle (with median and lateral apertures - where fluid leaks to subarachnoid space in meninges) - central canal |
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Name the five lobes of the cerebrum.
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- Frontal
- Parietal - Temporal - Occipital - Insula (the deep one) |
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Identify the sulci that separate one lobe from another.
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Central sulcus - separates frontal lobe and parietal lobe
Parieto-occipital sulcus - separates occipital love and parietal lobe (on medial surface of hemisphere) Lateral sulcus - separates temporal lobe from parietal and frontal lobe |
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Precentral gyrus
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Elevated ridge of tissue that borders the central sulcus (which separates frontal and parietal lobes) anteriorly
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Postcentral gyrus
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Elevated ridge of tissue that borders the central sulcus (which separates frontal and parietal lobes) posteriorly
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Identify the fissures that separate one lobe from another.
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Longitudinal fissure - separates cerebral hemispheres
Transverse cerebral fissure - separates cerebral hemispheres from cerebellum |
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What is the function of the meninges?
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Surround and protect brain and spinal cord
Made of 3 layers of tissue separated by spaces or potential spaces Dura mater - subdural space - arachnoid - subarachnoid space (with CSF) - pia mater |
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List the meninges and spaces in order (from superficial to deep).
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- Dura mater (tough outer layer) - superficial and meningeal layer
- Sub-dural space - thin fluid layer - Arachnoid - thin transparant - Subarachnoid space - CSF circulates - Pia mater - transparent inner layer |
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In what meningeal space does CSF circulate?
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Subarachnoid space
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Which of the meninges adheres to the brain?
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Pia mater - transparent inner layer
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What is the function of CSF?
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Circulation - nourish the brain
Chemical protection - difft. composition from plasma of blood (more Na Cl H, less Ca K) Mechanical protection - reduces brain wt., protects from shock |
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Describe the structure and function of a choroid plexus.
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Network/clusters of capilaries
Hang from roof of ventricles Covered by ependymal cells Have ion pumps to modify filtrate from bloodstream - They produce CSF! |
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Where are choroid plexuses located?
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Hang from roof of ventricles, covered by ependymal cells
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What cells produce CSF?
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Choroid plexus
Broad thin walled capillaries Hang from roof of ventricles, enclosed by pia mater and layer of ependymal cells lining the ventricle Ependymal cells have tight junctions and ion pumps to modify the filtrate |
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Describe the path of CSF circulation, beginning at the lateral ventricles.
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- Lateral ventricles
- through interventricular foramen to third ventricle - Through cerebral/mesencephalic aqueduct to fourth ventricle - To the subarachnoid space (through 3 openings in roof of 4th ventricle, median aperture, 2 lateral apertures) - Circulates in subarachnoid space until reabsorbed in blood vascular sinuses (through arachnoid villi) |
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What is the function of the arachnoid villi?
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Reabsorbs CSF from subarachnoid space into blood vascular sinuses
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What structural features create the blood brain barrier?
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- Tight junctions between adjacent epithelial cells in walls of cerebral capillaries
- Astrocyte processes (supply signals to endothelial cells, causing them to make the tight junctions) |
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What is the function of the blood-brain barrier?
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- Inhibits passage of materials from systemic circulation into brain tissue
- Brain needs constant internal environment - otherwise with chem variation, neurons would fire incontrollably, since many of the chem are used as NTs |
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What is the functional significance of the circumventricular organs (CVOs)?
Identify the main CVOs. |
- Hypothalamus, pituitary, pineal gland, etc
- Monitor changes, and coordinate homeostatic activities in response to changes in blood chemistry |
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What is the general function of the primary motor cortex?
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- Controls voluntary contractions of specific muscles/groups of muscles on opposite side of body
- Skeletal muscles |
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What is the general function of the premotor cortex?
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- Planning movement
- Controlling learned movements like playing scales |
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What is the general function of Broca's area?
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- The motor speech area
- Translating thoughts to speech - Damage = non-fluent aphasia; know what to say but can't get it out of your mouth |
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What is the general function of the frontal eye field?
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- Voluntary scanning movements of the eye
- Scanning a page - Damage = trouble reading b/c eyes can't track |
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What is the general function of the primary auditory cortex?
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- input from cochlea of inner ear
- Interprets pitch, rhythm, loudness, location - Basic premises of sound |
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What is the general function of the auditory association area?
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- Perception/interpretation of sound
- memories of previous auditory experiences so we can identify it - speech interpretation |
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What is the general function of the vestibular cortex?
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- conscious awareness of balance
- input from vestibular apparatus (semicircular canals) in ear |
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What is the general function of the prefrontal cortex?
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- anterior association area
- very complicated processing involved with intellect and complex learning - personality, conscience, abstract thinking, (mood and emotions somewhat) - undeveloped in children |
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What is the general function of the general interpretative area?
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- includes Wernicke's area and gnostic area
- all of the association areas converge into this area - vital for intellectual functioning - Damage = you could read a paragraph, but have no idea what thoughts were being conveyed |
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What is the general function of the primary smoatosensory cortex?
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- recieves sensory stimuli (from somatic sensors in skin and proprioceptors in joints and muscles) from the opposite side of body
- Spatial discrimination (we know what part of the body is being stimulated |
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What is the general function of the somatosensory association area?
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- integrating and interpreting sensory inputs (touch, press, temp)
- w/o looking, you can know where your foot is |
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What is the general function of the prinary visual cortex?
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- sensory input regarding shape, color, movement
- from rods and cones in eyes |
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What is the general function of the visual association area?
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- Input from primary visual cortex and thalamus
- interpret info; know you're looking at a person, at your friend |
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What is the general function of the olfactory cortex?
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- Input related to smell; conscious awareness of odors
- part of the rhine encephalon |
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What is the general function of the gustatory cortex?
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- taste stimuli are consciously perceived
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What is the general function of the affective language area?
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- a posterior association area (along with the general interpretative area/wernicke's area and gnostic area)
- nonverbal, emotional components of language - Damage = can't read emotion in a sentence like "I was in a car accident and my husband was killed" "oh that's too bad" |
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Within what lobe or region of the cerebrum is the prime mary motor cortex located in?
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- precentral gyrus of each frontal lobe
- contains pyramidal cells - large motor neurons; long axons; creates corticospinal/pyramidal tracts |
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Within what lobe or region of the cerebrum is the premotor cortex located in?
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- frontal lobe
- just anterior to precentral gyrus - communicates w/basal nuclei |
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Within what lobe or region of the cerebrum is Broca's area located in?
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- frontal lobe
- just above lateral sulcus - anterior to inferior portion of premotor cortex - lateralized to left hemisphere |
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Within what lobe or region of the cerebrum is the frontal eye field located in?
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- frontal lobe
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Within what lobe or region of the cerebrum is the prinary auditory cortex located in?
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- superior part of temporal lobe
- near lateral cerebral sulcus |
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Within what lobe or region of the cerebrum is the auditory association area located in?
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- inferior and posterior to primary auditory cortex
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Within what lobe or region of the cerebrum is the vestibular cortex located in?
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- posterior insula
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Within what lobe or region of the cerebrum is the prefrontal cortex located in?
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- anterior portions of frontal lobes
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Within what lobe or region of the cerebrum is the general interpretative area located in?
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- posterior end of the lateral sulcus
- where all difft association areas converge - 1 hemisphere only (usu. left hem. in right handed ppl) |
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Within what lobe or region of the cerebrum is the primary somatosensory cortex located in?
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- postcentral gyrus of each parietal lobe
- get stimuli from opposite/contralateral side of body |
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Within what lobe or region of the cerebrum is the somatosensory association area located in?
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- just posterior to primary somatosensory cortex
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Within what lobe or region of the cerebrum is the primary visual cortex located in?
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- extreme posterior tip
- medial surface of occipital lobe at calcarine sulcus - note:medial surface of occipital lobe is in the longitudinal fissure |
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Within what lobe or region of the cerebrum is the visual association area located in?
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- surrounds primary visual cortex in occipital lobe
- input from primary visual cortex and thalamus |
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Within what lobe or region of the cerebrum is the olfactory cortex located in?
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- primarily in medial aspect of temporal lobe
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Within what lobe or region of the cerebrum is the gustatory cortex located in?
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- mainly in the insula
- just above lateral cerebral sulcus - deep to temporal lobe |
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Within what lobe or region of the cerebrum is the affective language area located in?
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- opposite hemisphere from general interpretive center
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What is meant by the term hemispheric (or cerebral) lateralization?
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- 2 cerebral hemispheres (although they look the same) are slightly difft in structure and function
- each hemisphere tends to be involved w/sensory and motor functions of the opposite side of the body |
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What is meant by the term cerebral dominance?
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- designates hemisphere that is dominant for language
- left cerebral hemisphere for language math and logic - right for visual, spatial ,intuition, emotion - if dominant is left, then you will be right handed (90% of people) |
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Which is the dominant hemisphere for most people?
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Left hemisphere (90%) - so most people are right hnded
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What are the major functions of the dominant hemisphere?
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Left hemisphere - language, math logic
- dominance designates the side dominant for language |
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What are the major functions of the non-dominant hemisphere?
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Right hemisphere - visual, spatial, intuition, emotion
- dominance designates the side dominant for language |
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Name and identify the function of the three different types of fiber tracts in the brain.
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Commissures/commissural tracts (ex. the corpus callosum) - gonnect gyrea in the difft hemispheres; anterior and posterior commissure
Association fibers/tracts - connect b/w difft parts in SAME hemisphere; fibers can be short (arcuate fibers b/w adjacent gyrus) or long (fasciculi from one lobe to another) Projection fibers/tracts (ex. internal capsule) - ascend/decend from cortex; connect cortex w/ brains stem, spinal cord, lower parts of brain |
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Internal capsule
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- a projcection fiber/tract
- goes up through brainstem to primary motor cortex - bass by basal nuclei creating gray and white striped look (why we call basal nuclei in 1 hemisphere the corpus striatum) - past basal nuclei they fan out (coronal radiation) |
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What are the basal nuclei?
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- gray matter, inferior to floor of lateral ventricles
- caudate nucleus, globus pallidus and putamen control large automatic movemtns of skeletal muscles - regulate intensity of movement and inhibit unwanted movements |
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What structures comprise the basal nuclei?
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- Caudate nucleus
- Lentiform nucleus: - globus pallidus and putamen |
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What are the general functions of the basal nuclei?
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- control/regulate large automatic movements of skeletal muscles (like swinging your arms while you walk)
- regulate intensity of movement - prevent unwanted movements |
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Amygdala
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Nucleus sits on tail of caudate nucleus
Structurally associated with basal nuclei Functionally associated with limbic system |
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What structures are included in the diencephalon?
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- forms roof and walls of 3rd ventricle
- Thalamus - Hypothalamus - Epithalamus |
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Parkinson's disease
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Degeneration of dopamine-releasing neurons of substantia niagra
Basal nuclei are deprived and become overactive - tremors, slow in initiating and executing movement |
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What is the major function of the thalamus? Other functions?
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- Main: relay of sensory information
- sensory input to cerebral cortex - role in awareness, sensory integration, cognition, mood, motor function |
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What region of the diencephalon serves as a link between the nervous and endocrine systems?
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The hypothalamus
- it regulates activity of the pituitary gland |
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What are the major functions of the hypothalamus?
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- Control of the Autonomic nervous system (sympathetic and parasympathetic systems, HR, BP, contractility of heart, rate/depth of breathing, constriction of iris, contraction of urinary bladder.... )
- Control of endocrine system functioning (regulates pituitary gland) - Center for emotional response (part of lymbic system, connectionj w/thalamus centers in brain stem) - Body temp regulation - Regulation of eating and drinking - Regulation of sleep-wake cycles |
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Concussion
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Alteration in brain function (usu. temporary), following a blow to head
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Contusion
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Bruising of the brain and permanent neurological damage
A more serious type of concussion (caused by a blow to the head) |
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Hydrocephalus
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When circulation or drainage of CSF is obstructed
CSF accumulates and exerts pressure on brain In baby, the head gets bigger, in adults, brain damage occurs Treated by inserting a shunt into ventricles to drain fluid into abdominal cavity |
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What gland produces and secretes Melatonin? What is the function of this hormone?
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- the epithalamus (specifically, the pineal gland which extends from the posterior border of the epithalamus)
- sleep/wake cycles; circadian rhythms |
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Where is the limbic system located?
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- functional organization of structures
- medial aspect of cerebral hemispheres and diencephalons - ring around top of brain stem |
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What structures make up the limbic system?
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- cingulate gyrus, parahippocampal gyrus, dentate gyrus
- hippocampus and amygdala - parts of several nuclei of thalamus and hypothalamus (parts of diencephalon) - fornix and other tracts (how limbic system communicates) |
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What are the functions of the limbic system?
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- affective/emotional brain
- links unconscious functions of brainstem (autonomic functions that regulate visceral functions) with conscious functions of cerebral cortex) - consciously aware of emotional state - memory storage and retrieval - hippocampus - regulates/mediates response to stress |
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Identify the three major regions of the brain stem.
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- midbrain
- pons - medulla oblongata |
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What structures are located in the midbrain?
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Cerebral aqueduct
Cerebral peduncles - large pyramidal motor tracts Superior cerebellar peduncles - contain midbrain w/in cerebellum Corpora quadrigemina - 4 reflex centers R+L substantia nigra - makes dopamine from melanin R+L red nuclei - high blood supply and iron; neurons from cerebral cortex and cerebellum synapse Nuclei of 2 pairs of CNs:III and IV - ocular motor nerve and trochlear motor nerve |
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What is the function of the nuclei of the substantia nigra?
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In midbrain
Contains melanin; precurser to dopamine; affect in basal nuclei Die in parkinsons, so too little dopamine |
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What is the function of the nuclei of the corpora quadrigemina?
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Two superior colliculi - reflex centers for movements of eyes, head and neck in response to primarily visual stimuli
Two interior colliculi - reflex centers for movements of head and trunk in response to auditory stimuli |
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What important structures are located in the pons?
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Deeper longitudinal tracts - connect cerebrum and spinal cord
Middle cerebellar peduncles - connect pons with corresponding side of cerebellum Nuclei of 4 paris of CN's V - trigeminal n.; VI - abducins n.; VII facial n.; VIII - vestibulocochlear n. Pneumotaxic and apneustic centers - respiratory |
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What is the function of the pneumotaxic and apneustic areas?
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- Respiratory centers
- Work closely with respiratory centers in medula - Rate/depth of breathing |
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What important structures are located in the medula oblongata? Identify the general function of each.
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Pyramids - descending motor tracts; go from primary motor cortex to spinal cord; cross over at decussation of pyramids
Olives - inferior olivary nuclei relay sensory input from proprioceptors to cerebellum; joint position, amt of stress Nucleus gracilis and nucleus cuneatus - relay station for sensory info to somatosensory cortex Inferior cerebellar peduncles - tracts connect medulla and cerebellum Nuclei of 5 pairs of CNs (VIII-XII) Visceral motor nuclei |
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What happens in the decussation of the pyramids?
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Crossover of fibers in pyramidal tract in medulla
Why brain controls motor functions contralaterally |
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Identify and describe the function of the main visceral motor nuclei of the medulla.
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Cardiovascular center - HR, vasomotor function/constriction of blood vessels
Medullary respiratory centers Other centers - involuntary motor functions - coughing, sneezing, hiccuping, swallowing, etc |
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What is the reticular formation?
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- 3 columns
- part of brain stem - sensory and motor function; input from cerebral cortex and hypothalamus, projects to multiple locations in cerebral cortex and spinal cord Pain, visceral inputs, posture, muscle tone, reflex eye movements; cardiovascular and respiratory function |
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Where is the reticular formation located?
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Extends through the central region of the brainstem
Collection of nuclei and the tracts b/w them Neurons form 3 columns that extend the length of the brain stem |
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With what other structures (or regions) of the brain is the reticular formation connected?
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Part of brain stem- medulla oblongata; pons; midbrain;
Involved in activating/arousing the cortex to a state of consciousness Input from cerebral cortex and hypothalamus Output to cerebral cortex and spinal cord |
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What is the function of the reticular activating system (RAS)?
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- In reticular formation in brain stem
- arouse cortex to state of consciousness - Communication b/w reticular formation and cerebral cortex Filters out unnecessary stimuli; provides enough stimuli so cer. cortex stays alert |
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Coma
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When the reticular activating system isn't working, so your cerebral cortex can't be aroused
No level of concsiousness |
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Describe the general structure of the cerebellum.
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- Large mass of tissue on dorsal surface
- Below occipital lobes - Posterior to pons and medulla - separated from cerebrum by transverse fissure and tentorium cerbelli (dura mater) - Lateral hemispheres connected by narrow vermis - Fissures divide it into 3 lobes Falx cerebelli separates and anchors the 2 hemispheres Cortex has folia (gyri) Has arbor vitae Connected to brain stem by 3 cerebellar peduncles (superior, middle, inferior) |
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What are the functions of the cerebellum?
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- Muscular activity, smooth motions, regulating posture and balance, muscle tone
- comparator function - compares intended movement with actual movement - knowing current body position (unconscious level) |
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Ataxia
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Cerebellar injury - results in marked loss of muscle tone and motor coordination/smoothness
- balance deterioration; similar effect to alcohol suppression of the same area |
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superior colliculus
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- In midbrain - part of brain stem
- 2 of them - reflex center for movements of eyes, head, neck in response to visual/other stimuli |
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Inferior colliculus
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- In midbrain - part of brain stem
- 2 of them - reflex center for movements of head and trunk in response to auditory stimuli |
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Decussation
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Refers to the decussation of the pyramids
Crossover of the fibers in the pyramidal tract (in medulla, in brain stem) |
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Cerebellar Peduncles
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3 - superior, middle, inferior
Carry sensory and motor impulses Connect cerbellum to rest of brain |
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Arbor vitae
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part of cerebellum
"tree of life" White matter in the cerebellum resembles a tree |