Neuromusculoskeletal System Exam I Content

C) spina bifida cystica: meningomyelocele D) spina bifida cystica: myeloschisis

define the type of spina bifida: C) D)

non-modifiable modifiable

risk factors of stroke: 1) __________________: A) age B) family history 2) _________________: A) hypertension B) diabetes C) tobacco use D) cardiac disease E) elevated cholesterol

pia mater

thin layer of connective tissue that closely adheres to the surface of the brain and spinal cord, and projects into fissures and sulci

ACA MCA PCA

(3) classic syndromes of stroke

periosteal meningeal dural border cells

(3) layers of the dura mater, from outer to inner

anterior circulation posterior circulation Circle of Willis

(3) major blood supplies of the brain

meningocele meningomyelocele (also known as myelomeningocele) myeloschisis

(3) types of spina bifida cystica

anterior cerebral artery (ACA) middle cerebral artery (MCA) branches of the MCA posterior cerebral artery (PCA)

(4) major arteries supplying the brain

1) cell bodies 2) axons

1) _____________: collectively called "gray matter" 2) ______________: collectively called "white matter"

1) corticospinal tract 2) paresis; plegia 3) basal ganglia

1) the ____________ tract from the brain to the spinal cord provides strength to movements and controls the activity of the spinal motor neurons 2) just as with the fine touch and pain pathways we learned, damage to any part of this will cause a loss of overall function; in this case, that means weak movements ("________") or even paralysis ("__________") 3) the _______________, mentioned in passing in the previous material, receive a copy of the brain's motor plan (e.g. "I want to turn the doorknob") and advise the brain on the sequence of muscle movements that is best for achieving that goal; it's like getting a consult these then send their advice through the thalamus and up to the motor cortex; the basal ganglia helps initiate the desired sequence of movements while suppressing unwanted sequences; this says the lights turn on in the correct sequence and not at the wrong times

1) floor plate: ventral motor neurons 2) roof plate: dorsal sensory neurons

1) the floor plate influences cell fate, including the development of the (ventral/dorsal) (motor/sensory) neurons 2) the roof plate also influences cell fate, including the development of the (ventral/dorsal) (motor/sensory) neurons

1) cerebellum 2) basal ganglia and cerebellum

1) the fluidity, coordination, and fine detail of movements are supported by the _______________ this receives a copy of the motor plan as well, and also receives sensory information about how your body is positioned and where it is in relation to other things in the world; it uses that information to compare what was planned to what is actually happening in the body; was the arm moved to the correct position to turn the doorknob as a result or the muscle contractions carried out? if not, then the activity of the motor cortex needs to be corrected and fine-tuned this corrective, coordinating information is also passed through the thalamus to the motor cortex as well 2) in essence, the motor cortex has two advisors that help it do its job: the ______________ and ____________; they help the motor cortex know how much and when to tell the motor neurons what to do; together they create strong, correct, fluid movements

spina bifida occulta spina bifida cystica

2 types of spina bifida

D) Left Thalamus

A 67-year-old patient presents to the clinic with a concerning development. Following a stressful life event, the patient reports that they awoke to find they are unable to feel pain from the entire right side of their body. A lesion in which of the following locations would most likely account for this patient's symptom? A) High cervical spinal cord on the right side B) Right Thalamus C) Mid-thoracic spinal cord on the left side D) Left Thalamus

C. Parkinson's disease

A 70-year-old patient reports that their previous symptoms of muscle rigidity and tremor have significantly improved after you started this patient on pramipexole, a dopamine agonist. Which diagnosis does this patient likely have? A. Alzheimer's disease B. Schizophrenia C. Parkinson's disease D. Depression

A. Cholinergic

A 68-year-old patient presents with progressive memory decline. If you treated this patient with medication, the drug would most likely act on which of the following neurotransmitters? A. Cholinergic B. Dopaminergic C. Serotonergic D. Histaminergic

D) vision

A patient survives a car accident in which their head impacted with part of their car's interior. Neuroimaging reveals the patient has sustained damage to the most caudal portions of their cerebral cortex in both the right and left hemispheres. Impairment of which of the following would most likely be observed upon examination of this patient in the clinic? A) voluntary movement B) sensation from body wall C) auditory sensation D) vision

B) basal ganglia

A patient reports to the clinic with large, involuntary flinging motions of one limb. The patient reports they cannot suppress these, they "just happen all the time." Which of the following components of the nervous system has most likely been damaged? A) motor cortex B) basal ganglia C) cerebellum D) peripheral nerves

midbrain nuclei → thalamus

ACh pathways: ___________________ pathway: play a role in the arousal and sleep-wake cycles; these neurons are also referred to as "locomotor neurons" because stimulation of these neurons in animals cause coordinated movements

nucleus basalis (of the basal forebrain) → hippocampus and cerebral cortex

ACh pathways: _____________________ pathway: these projections are important for learning and memory functions of the brain; degeneration of cholinergic neurons is significant in patients with Alzheimer's disease

nucleus basalis (of the basal forebrain) → hippocampus and cerebral cortex midbrain nuclei → thalamus

ACh pathways: cholinergic neurons use acetylcholine (ACh) as their neurotransmitter these neuronal cell bodies are widely distributed in the CNS, and almost all regions of the brain are innervated by cholinergic neurons what are these (2) pathways?

small molecule neurotransmitters (amines)

ACh, DA, NE, 5-HT, and histamine are what type of neurotransmitters?

A. Loss of pain and temperature sensation

An infarct of the Anterior Spinal Artery can lead to which of the following deficits: A. Loss of pain and temperature sensation B. Loss of proprioception C. Loss of vibration sensation D. Loss of speech

volume: ~150mL produced in the choroid plexus A) 20mL/hour B) 500mL/day

CSF, continued: 1) volume: approximately ______mL 2) produced in the __________________ A) _____ mL/hour B) _____ mL/day 3) pressure: 10-20 cm of H2O

A. Arachnoid granulations

Cerebrospinal fluid is resorbed into the venous system through: A. Arachnoid granulations B. Pia mater C. Dura mater D. Choroid plexus E. Blood-CSF barrier

mesocortical pathway

DA pathway: dopaminergic neurons in the ventral tegmental nuclei/area (VTA) project fibers to the prefrontal cortex these projections play a role in cognitive and executive functions, and emotional response hypofunction of this pathway is associated with the negative symptoms of schizophrenia (emotional, social, and cognitive, e.g. flat affect and limited speech) note: it is worth mentioning that schizophrenia neurobiology is very complex and has its limitations

mesolimbic pathway

DA pathway: here, dopaminergic neurons in the ventral tegmental nuclei/area (VTA) project fibers to many forebrain areas, but the most important being the nucleus accumbens (NA) the nucleus accumbens is part of the limbic system and plays a role in the "reward system" to reinforce behaviors associated with addiction; therefore, people will alter their behavior to stimulate this pathway: drug abuse, gambling, drinking, etc. the ventral tegmental neurons also project to areas of the prefrontal cortex and amygdala so that these addictive behaviors can be remembered and repeated in the future; in addition to the reward system, increased dopamine and an overactivity in this pathway is associated with positive symptoms of schizophrenia (delusions, hallucinations) this pathway is the therapeutic target of antipsychotic drugs to decrease positive symptoms of schizophrenia by way of postsynaptic D2 receptor antagonism

nigrostriatal (mesostriatal)

DA pathway: this pathway contains about 80% of the brain's dopamine dopaminergic neurons in the substantia nigra (pars compacta) project fibers to the striatum (the striatum is a part of the basal ganglia, and is comprised of the caudate nucleus and the putamen) where dopamine facilitates the initiation of voluntary (purposeful) movements, and motor planning movement disorders in Parkinson's disease such as muscle rigidity and tremor (extrapyramidal symptoms) results from a progressive degeneration of dopaminergic neurons within the substantia nigra (often treated with D2 agonists)

their cell bodies are found in the substantia nigra (specifically the pars compacta) and ventral tegmental area/nuclei of the midbrain

DA pathways, continued: where the the cell bodies for dopaminergic neurons located?

nigrostriatal (mesostriatal) mesolimbic mesocortical

DA pathways: dopaminergic neurons use dopamine (DA) as their neurotransmitter their cell bodies are found in the substantia nigra (specifically the pars compacta) and ventral tegmental area/nuclei of the midbrain what are the (3) DA pathways?

A. absence of the forebrain

Failure of anterior neuropore closure results in which malformation? A. absence of the forebrain B. meningomyelocele C. absence of the spinal cord D. hydrocephalus E. Spina bifida occulta

D. sixth month

Myelination begins approximately during which period of gestation? A. fourth week B. sixth week C. third month D. sixth month E. fourth month

locus ceruleus

NE pathway: noradrenergic neurons are in a region of the midbrain and the pons called the ________________ ("blue spot") these neurons have a very widespread distribution in the CNS (cerebral cortex, thalamus, hypothalamus, cerebellum, brainstem, and spinal cord) the locus ceruleus is activated by new, unexpected, non-painful sensory stimuli and is least active when a person is not vigilant the NE system is involved in many behavioral and physiological processes which include, but are not limited to mood, arousal, and regulation of the sleep-wake cycle firing of noradrenergic neurons in the locus ceruleus increases in the awake state and decreases during sleep; NE, together with serotonin, plays an important role in the modulation of pain and mood disorders (depression, anxiety, obsessive compulsive disorder)

D. nucleus accumbens

Neural activity within which brainstem region or nucleus is increased when a gambler pulls the lever on a slot machine? A. locus ceruleus B. raphe nucleus C. tuberomammillary nucleus D. nucleus accumbens E. substantia nigra

C. Sensory loss with variable weakness

Occlusion of the posterior spinal artery will cause: A. Bilateral lower extremity weakness without sensory loss B. Bilateral upper extremity weakness without sensory loss C. Sensory loss with variable weakness D. Upper extremity sensory loss and lower extremity weakness

C. medulla

The myelencephalon gives rise to which adult structure? A. cerebral cortex B. midbrain C. medulla D. cerebellum E. diencephalon

B. The dural border cell layer

The plane of structural weakness in the dura mater is: A. The subdural space B. The dural border cell layer C. Calvarial portion D. Cuboidal epithelium

C, A) medial, dorsal

The portion of the homunculus that handles sensation from the leg is _______ and somewhat ______ to the portion that handles sensation from the face. A) dorsal B) ventral C) medial D) lateral

C. External to the pia mater and internal to the arachnoid mater

The space where CSF is found bathing the spinal cord is: A. External to the arachnoid mater and internal to the dura mater B. External to the dura mater C. External to the pia mater and internal to the arachnoid mater D. Deep to the pia mater

D. Cervical region

The spinal cord region with the highest amount of white matter is: A. Sacral region B. Lumbar region C. Thoracic region D. Cervical region

A, D) dorsal, caudal

The thalamus is _______ and somewhat _______ to the hypothalamus A) dorsal B) ventral C) rostral D) caudal

C) sagittal

To observe the full length of the corpus callosum in a single image, the best orientation for that image would be which of the following? A) coronal B) horizontal/axial C) sagittal

C. Depression

What disorder is often improved by drugs that block serotonin re-uptake? A. Addiction B. Hallucinations C. Depression D. Tremor E. Limited speech

C. pseudounipolar

What type of neuron is located in the dorsal root ganglion and provides communication between the skin and the spinal cord? A. multipolar B. bipolar C. pseudounipolar D. unipolar

D. C6 dermatome

When performing a physical exam, you notice a loss of sensation in your patient's thumb and their lateral aspect of the forearm on the ipsilateral forearm. Which dermatome/spinal nerve do you think is mostly involved in this deficit? A. T1 dermatome B. C5 dermatome C. T4 dermatome D. C6 dermatome

B. Schwann cell

Which cell type forms myelin sheaths around peripheral nerves found in the limbs? A. Oligodendrocyte B. Schwann cell C. Ependymal cell D. Satellite cell

A. Glutamate

Which of the following is the major fast excitatory amino acid neurotransmitter in the brain? A. Glutamate B. GABA C. Dopamine D. Substance P E. Acetylcholine

C. formation of the three primary brain vesicles

Which of the following occurs during the 4th week of gestation? A. formation of the fourth ventricle B. formation of the corpus callosum C. formation of the three primary brain vesicles D. formation of the three germ layers E. formation of the five secondary brain vesicles

B. alar plate

Which of the following regions contain afferent neuron precursors of the spinal cord? A. neural plate B. alar plate C. basal plate D. roof plate E. floor plate

GFAP

__________: astrocyte marker

ependyma

___________: glial cells that form the lining of ventricular system, and secrete about 20% of CSF

spina bifida

______________: malformation involving incomplete closure of the posterior neuropore and incomplete fusion of vertebral arches involvement of the spinal cord in in this malformation ranges from clinically insignificant to severe, with most defects occurring in the lumbosacral region

anencephaly

_______________: defective closure of the anterior neuropore; usually fatal because the forebrain does not form and the calvarium is open

synaptic transmission

________________________ is a targeted and rapid response between a presynaptic neuron directly influencing a postsynaptic neuron, through fast excitatory or inhibitory electrical events (EPSPs and IPSPs) the postsynaptic neuron summates EPSPs and IPSPs from presynaptic neuronal inputs, and the electrical potential must exceed threshold to initiate an action potential the summation of EPSPs and IPSPs to create an action potential is an all-or-nothing event and can be thought of as a binary process (e.g. yes/no, on/off)

1) midbrain or below A) superior: rostral B) inferior: caudal C) anterior: ventral D) posterior: dorsal 2) above the midbrain A) superior: dorsal B) inferior: ventral C) anterior: rostral D) posterior: caudal

anatomical directional terms for the CNS: 1) regarding a location at the midbrain or below, describe the 4 anatomical directions 2) for above the midbrain, describe the different terms used note: the terms superior, inferior, anterior, and posterior can be used universally

primary neuron cell body is in the dorsal root ganglion (DRG) it synapses with a secondary neuron in the dorsal horn 1) reflexes 2) modulation (of the painful signal)

anatomy of pain perception, 1st neuron: the primary neuron is the first neuron to detect pain (1°), and has its cell body in the __________________; it has a distal fiber that detects a painful sensation in the skin, and that information is passed along the neuron to its proximal fiber and into the spinal cord; there, in the _______________, it synapses (note the triangular symbol) onto a secondary neuron (2°) why does it synapse? it's not like the first neuron is tired, but having a synapse there allows for several important things: 1) ___________ to elicit a movement away from the painful thing; some neurons in the dorsal horn can speak directly to ventral horn cell bodies that in turn talk to muscles and get them to withdraw your limbs from harmful stimuli 2) ___________ of the painful signal; first, fibers carrying non-painful touch sensation can also synapse onto those secondary pain neurons, and when activated, actually quiet them down; that's why rubbing your toe after you hit it on furniture makes it feel better; second, the brain uses descending fibers to release chemicals onto these secondary pain neurons in order to suppress pain signaling note, this is a site where opioids act, and is a very big part of the science behind the opioid crisis in the U.S.

1) decussate 2) secondary neurons synapse in the thalamus, onto tertiary neurons

anatomy of pain perception, 2nd neuron: 1) the secondary neurons have axons that cross the midline to ascend on the opposite side of the spinal cord in a bundle (the shaded red area); why do they do cross before ascending? nobody knows! but as you'll see later, many tracts (bundles of axons in the CNS) cross or "________________" knowing the different places where different tracts decussate will be essential to understanding the nervous system; pain decussates immediately in the spinal cord: other spinal cord pathways do not 2) the axons of the second order neurons ascend through the brainstem and up to the ______________, where they synapse onto a tertiary neuron (3°)

primary neurons secondary neurons tertiary neurons

anatomy of pain perception, overview: let's say a person gets punched in the upper arm; in order to get that painful information from the arm up to the cortex, 3 neurons are needed, including elements in the PNS and CNS what are these (3) neurons? we'll map these elements using this coronal map of the brain and brainstem (see image), with an axial view of the spinal cord note the magnified view of the spinal cord in cross-section on the left, which is just there to help with visualization

1) smell; modulation 2) cortex; homunculus

anatomy of pain perception, the 3rd neuron: 1) as stated earlier, all information going into the cortex must first go to the thalamus (the one exception to this is ____________ , but we'll talk about that later); why synapse onto the thalamus instead of passing right through? same big reason as the last synapse we saw: it's an opportunity for _____________ of that signal; in this case, it's for the thalamus to only let through what the cortex tells it to 2) from the thalamus, third-order (or tertiary) neurons project to the ____________, but not just anywhere; the neurons of the sensory cortex are arranged in such a way that inputs to it are exquisitely ordered on a map of the body; this body map, called the _______________, allows the brain to know exactly which part of the body is feeling something and direct attention where it's needed this same body map is used in the motor cortex so that when you need to move your arm to defend yourself, you don't accidentally move your leg instead; in the crucible of evolution, this kind of precision is critical

3) CSF 5) arachnoid villi (arachnoid granulations)

arachnoid mater: 1) located between dura and pia mater 2) consists of arachnoid barrier cell layer and arachnoid trabeculae 3) ________ is located in subarachnoid space (SAS) between arachnoid and pia 4) subarachnoid cisterns are enlargements of subarachnoid space 5) CSF flows from the SAS into the dural venous sinuses through the __________________

1) intercellular channels: between cells 2) mediated transport: through cells

arachnoid villi (arachnoid granulations): these are the location of transfer of CSF into venous sinuses mechanisms of transfer involving arachnoid cap cells include: 1) intercellular channels (between/through) cells 2) mediated transport (between/through) cells

1) neuronal cell body, axon 2) are NOT recycled back after secretion 3) co-localization

biosynthesis of neuropeptides: 1) neuropeptides are large peptides synthesized and packaged into synaptic vesicles in the ______________________; the synaptic vesicles are then transported down the _________ by microtubules to the presynaptic terminals 2) unlike small molecule neurotransmitters, neuropeptides (are/are NOT) recycled back into the neuron after secretion but are broken down by peptidases on the receptor membrane small molecule neurotransmitters and neuropeptides may coexist in the same nerve terminal with other neurotransmitters and neuropeptides, which is called ________________

presynaptic terminal

biosynthesis of small molecule neurotransmitters: small molecule neurotransmitters are synthesized and packaged into synaptic vesicles in the __________________ for fast release either all or part of the molecule is recycled back into the presynaptic terminal for example, acetylcholinesterase splits acetylcholine into acetic acid and choline in the synaptic cleft, and choline then gets recycled back into the presynaptic terminal and used to make more acetylcholine

anterior spinal artery posterior spinal artery Artery of Adamkiewicz

blood supply of the spinal cord: 1) _______________: supplies the anterior cord and lateral corticospinal tracts; occlusion results in bilateral weakness 2) _______________: is paired, and supplies the posterior columns and lateral corticospinal tracts; occlusion results in sensory deficits and possibly weakness 3) _________________: this is the spinal cord watershed area in the lower thoracic and upper lumbar region; may be damaged during aortic surgeries

SAS: 20% ventricular system: 80%

cerebrospinal fluid (CSF): this creates a protective environment for the brain location: 1) subarachnoid space (SAS): ___% 2) ventricular system: ___%

larger peptides (neuropeptides)

cholecystokinin, substance P, enkephalin, and somatostatin are what kind of neurotransmitters?

lateral ventricles and the roof of the 3rd and 4th ventricles choroidal arteries Na+/K+ ATPase; carbonic inhibitors

choroid plexus: this is the site of most CSF, and is located in the ____________ ventricles and the roof of the _______ and ________ ventricles its blood supply is via the _______________ arteries in secretion of CSF, fluid moves from the capillary through collagen, through choroid epithelium, and subsequently, is secreted into the ventricle secretion is regulated by an ___________________ enzyme; ________________ inhibitors can decrease Na+ exchange, and thus decrease CSF secretion

3rd and 4th ventricles, do NOT have tight junctions

circumventricular organs, continued: theses structures are primarily located around the ________________________, have a fenestrated endothelium, increased pinocytic vesicles, and (have/don't have) tight junctions substances in the blood can easily be detected by neurons in these areas, and have a role in the secretion of neuropeptides and hormones

ACA

classic syndrome of stroke involving contralateral LE motor and sensory loss

PCA

classic syndrome of stroke involving homonymous hemianopia

MCA

classic syndrome of stroke involving: 1) contralateral hemiparesis 2) contralateral hemisensory loss 3) aphasia 4) homonymous hemianopia

sensory (afferent) motor (efferent) interneurons

classification of neurons by function divides them into what (3) categories?

multipolar bipolar pseudounipolar

classification of neurons by structure divides them into what (3) categories?

subarachnoid arteries

clinical consideration of the arachnoid mater: subarachnoid hemorrhage is bleeding in the _______________ space (arteries/veins) within the space rupture, causing hemorrhage can be a result of trauma or aneurysm

hydrocephalus

clinical considerations of the CSF: ______________: enlargement of the ventricles

A) spina bifida occulta B) spina bifida cystica: meningocele

define the type of spina bifida: A) B)

dermatomes myotomes

dermatomes, myotomes, and peripheral nerves: last, but not least, we must discuss dermatomes and how to differentiate and define them in comparison to myotomes and peripheral nerves both dermatomes and myotomes are representations of a single spinal nerve, but: ________________: are strips of skin that are innervated by a single spinal nerve (Figure 10) and ________________: are masses of muscle supplied by a single spinal nerve it must be noted, that although this general mapping of single spinal nerve innervation is known, there is overlap with adjacent dermatomes; therefore, sensory deficits to the skin are not usually noted unless two or more spinal nerves are lesioned

1) physical support 2) as there is no lymphatic system in the brain it has an excretory function and assists with excretion of toxins 3) intracerebral transport of hormonal factors 4) control of the chemical environment of the CNS

describe (4) CSF functions:

the thalamus is on either side of the midline, just above the top of the hypothalamus the hypothalamus is found just below and in front of the thalamus

describe the anatomical orientation of the thalamus and hypothalamus in relation to each other

dopaminergic neurons in the ventral tegmental nuclei/area (VTA) project fibers to the prefrontal cortex

describe the mesocortical pathway

here, dopaminergic neurons in the ventral tegmental nuclei/area (VTA) project fibers to many forebrain areas, but the most important being the nucleus accumbens (NA) the ventral tegmental neurons also project to areas of the prefrontal cortex and amygdala so that these addictive behaviors can be remembered and repeated in the future

describe the mesolimbic pathway

dopaminergic neurons in the substantia nigra (pars compacta) project fibers to the striatum (the striatum is a part of the basal ganglia, and is comprised of the caudate nucleus and the putamen)

describe the nigrostiatal (mesostriatal) pathway

the cerebellum is just posterior to the pons and medulla

describe the relation in positioning between the cerebellum and the pons and medulla

2 synaptic neurons 1 astrocyte

describe what the tripartitie synapse consists of

meningeal layer

dural folds: _______________: not a fold, but part of the dura mater that forms infoldings, and extends into the cranial cavity to help stabilize the brain

falx cerebri

dural folds: _________________: occupies the longitudinal fissure between hemispheres and encloses the superior sagittal sinus

tentorium cerebelli

dural folds: __________________: is located between the cerebrum and posterior fossa (infratentorial compartment containing the brainstem and cerebellum), dividing the posterior fossa from the hemispheres (the supratentorial compartment)

falx cerebelli

dural folds: ___________________: separates the 2 cerebellar hemispheres, with its base attached to the tentorium cerebelli

internal jugular vein

dural venous sinuses: these are located between the periosteal and meningeal layers of dura, and provide the major venous drainage paths for the brain, with blood and CSF draining ultimately into the ________________ vein there are NO valves in CNS venous system

agonists antagonist

effects of selected drugs: various drugs have effects on the CNS by acting as either an agonist or antagonist at a postsynaptic receptor drugs may also alter the efficiency of removal of transmitter from the synaptic cleft in various ways for example, dopamine (agonists/antagonists) such as cocaine and amphetamine block reuptake of norepinephrine and dopamine into the presynaptic terminal the result is that dopamine and norepinephrine remain in the synaptic cleft longer and in higher concentrations reserpine is an example of a dopamine (agonist/antagonist), which prevents the storage of dopamine in synaptic vesicles; several antipsychotic drugs that block dopamine receptors have been used to treat disorders like schizophrenia

CNS: tracts PNS: nerves

in the CNS, axons are mainly called ____________, whereas in the PNS, they're called _____________

neurons found in the eye and nose

give 2 examples of bipolar neurons

interneurons motor neurons secondary sensory neurons in the dorsal horns

give 3 examples of multipolar neurons

primary sensory neurons

give an example of pseudounipolar neurons

ependymal cells

glial cell which functions to: 1) are ciliated cells in direct contact with CSF 2) lines the ventricles of the brain and the central canal of the spinal cord

microglia

glial cell which functions to: 1) are derived from mesoderm 2) are the resident phagocytic scavenger cells of the CNS 3) become activated with tissue damage 4) those infected with HIV can fuse to form multinucleated giant cells

astrocytes

glial cell which functions to: 1) help to form the blood brain barrier (BBB) 2) support neurons structurally and functionally (tripartite synapse) 3) "mop-up" extracellular K+ ions and regulate extracellular PH to maintain neuronal homeostasis 4) regulate intracellular Ca2+ ion concentrations 5) recycle certain neurotransmitters that are released from nerve terminals (glutamate and GABA)

oligodendrocytes

glial cell which functions to: 1) in the white matter, a single one can extend multiple processes to myelinate many nearby axons at once (up to 60 axons) 2) in the gray matter, they provide nutritive functions 3) note: are injured in multiple sclerosis (MS) and leukodystrophies

Schwann cells

glial cells which function to: 1) can be myelinating and non-myelinating; one of these myelinates one internode of an axon 2) multiple axons that are unmyelinated in the PNS can be supported by the cytoplasm of one of these cells 3) aid in cleaning up debris 4) injured in Guillain-Barre syndrome

satellite cells

glial cells which function to: 1) cover the surface of nerve cell bodies in sensory, sympathetic, and parasympathetic ganglia 2) may aid in controlling the chemical environment of neurons

small molecule neurotransmitters (amino acids)

glutamate, γ-amino butyric acid (GABA), and glycine are what type of neurotransmitters?

tuberomammillary nucleus of the hypothalamus

histamine pathway: histaminergic neurons are located in the __________________ nucleus of the _______________, and have a widespread distribution in the CNS histaminergic neurons participate with cholinergic and serotonergic neurons to maintain the awake state/alertness antihistamine medications are thought to cause drowsiness by blocking histamine receptors of the CNS

1) alar plate: gives rise to the dorsal horns 2) basal plate: gives rise to the ventral and lateral horns

histodifferentation, continued: 1) the _______ plate gives rise to the dorsal horns of the mature spinal cord and contains neuroblasts that differentiate into sensory neurons 2) the _________ plate gives rise to the ventral AND lateral horns of the mature spinal cord, and contains neuroblasts that differentiate into motor neurons the 3 histological zones described before can be thought of as a basic organizational plan from which the spinal cord, brainstem, and forebrain arise from; this organizational plan is just more elaborate for the developing brainstem and forebrain

1) alar plate: sensory neurons 2) basal plate: motor neurons

histodifferentation, continued: 1) the alar plate gives rise to the dorsal horns of the mature spinal cord and contains neuroblasts that differentiate into (sensory/motor) neurons 2) the basal plate gives rise to the ventral AND lateral horns of the mature spinal cord, and contains neuroblasts that differentiate into (sensory/motor) neurons

gray matter, alar plate dorsally, and a basal plate ventrally

histodifferentation, continued: once the layers of the neural tube are established, a crease called the sulcus limitans appears within the walls of the central canal this sulcus divides the developing (white/gray) matter into an ________ plate, dorsally, and a ______ plate, ventrally

1) ventricular 2) intermediate, forms gray matter 3) marginal, forms white matter

histodifferentiation, continued: after the neural tube closes, it establishes 3 histological layers/zones: 1) _____________ zone: this innermost layer closest to the central canal contains progenitor cells that differentiate into all neurons and glial cells of the CNS (e.g. oligodendrocytes, astrocytes, microglia, ependymal cells) 2) ______________ zone: this middle layer contains cell bodies of post-mitotic neuroblasts (primitive neurons); this layer, along with contributions from the ventricular zone, forms the ______ matter of the CNS 3) _____________ zone: the outermost layer composed mainly of myelinated axonal processes from neurons located in the ventricular zone and intermediate zone; this layer forms the _______ matter of the CNS

marginal zone

histodifferentiation, continued: the outermost layer composed mainly of myelinated axonal processes from neurons located in the ventricular zone and intermediate zone; this layer forms the white matter of the CNS

ganglion

in the PNS, a collection of neuronal cell bodies is a ________________

intermediate zone

histodifferentiation, continued: this layer contains cell bodies of post-mitotic neuroblasts (primitive neurons); this layer, along with contributions from the ventricular zone, forms the gray matter of the CNS

ventricular zone

histodifferentiation, continued: this layer contains progenitor cells that differentiate into all neurons and glial cells of the CNS (e.g. oligodendrocytes, astrocytes, microglia, ependymal cells)

1) ventricular 2) intermediate 3) marginal

histodifferentiation: after the neural tube closes, it establishes 3 histological layers/zones:

mesocortical pathway

hypofunction of this pathway is associated with the negative symptoms of schizophrenia (emotional, social, and cognitive, e.g. flat affect and limited speech)

mesolimbic pathway

in addition to the reward system, increased dopamine and an overactivity in this pathway is associated with positive symptoms of schizophrenia (delusions, hallucinations) this pathway is the therapeutic target of antipsychotic drugs to decrease positive symptoms of schizophrenia by way of postsynaptic D2 receptor antagonism

nucleus

in the CNS, a collection of neuronal cell bodies is a ______________

bipolar

in this type of neuron structure, 2 processes radiate from each side of the cell body, with one process ending in dendrites and the other process (the axon), ending in axon terminals these neurons are found in the eye and nose and are associated with special senses (eg., smell, sight)

pseudounipolar

in this type of neuron structure, a single process arises from the cell body and then divides into two branches each branch is, structurally and functionally, similar to an axon; one branch projects to the periphery, while the other branch projects to regions in the CNS primary sensory neurons are examples of these types of neurons, and their cell bodies are located in dorsal root ganglia (DRG)

CNS

interneurons are found exclusively in the (CNS/PNS)

meningeal

layers of the dura mater: ___________: forms infoldings

dural border cells

layers of the dura mater: ___________: plane of structural weakness, and is the location of subdural hematoma

periosteal

layers of the dura mater: _____________: closely adhered to the calvarium

subfornical organ vascular organ of lamina terminalis neurohypophysis choroid plexus of 4th ventricle area postrema choroid plexus of 3rd ventricle subcommissural organ pineal gland

list the (8) organs which are circumventricular organs, areas in the brain without BBB

white matter 1) axonal tracts 2) commissural fibers 3) association fibers

location of neuronal axons: axons from neurons are found throughout the PNS and the CNS in the CNS, collections of myelinated and unmyelinated axons form the ______ matter; white matter can be classified based on the direction the axon bundles are moving here are a few examples: 1) ___________ (fasciculi, lemnisci): axons that ascend and descend through the brain and spinal cord (e.g., corticospinal tract) 2) ___________ fibers: axons that connect the cerebral hemispheres (e.g., corpus callosum) 3) ___________ fibers: axons that connect certain regions within the same hemisphere of cerebrum (e.g., cingulum)

gray matter ganglia

location of neuronal cell bodies: collections of neuronal cell bodies are located in the ___________ matter (cortex and nuclei) in the CNS neuronal cell bodies are arranged in layers on the surface of the cerebrum and cerebellum to form the cerebral cortex and the cerebellar cortex they're also arranged in clusters within deep nuclei found in the cerebrum, brainstem, and spinal cord neuronal cell bodies outside the CNS are found in ___________ (e.g., DRG, paravertebral ganglia, prevertebral ganglia)

MCA

major artery of the brain supplying the lateral convexity of hemisphere, including language areas, motor and sensory cortex

ACA

major artery of the brain supplying the medial surface of hemisphere (leg/foot area of motor and sensory cortex)

branches of the MCA

major artery of the brain supplying: 1) lateral striate (lenticulostriate) 2) penetrating branches of the MCA 3) internal capsule, putamen, and globus pallidus 4) distribution may cause hemiplegia

posterior circulation

major blood supply of the brain: ___________________: consists of the vertebral arteries (part of the vertebrobasilar system), which arise from the subclavian artery

Circle of Willis

major blood supply of the brain: ___________________: is especially important for collateral circulation channels between the anterior and posterior circulations, and between the left and right circulations if blood flow is reduced or occluded in internal carotid or vertebrobasilar system, it may be possible for blood from other sources to supply the deprived regions via this pathway

anterior circulation

major blood supply of the brain: ___________________: it consists of the internal carotid system, which consists of internal carotid arteries (ICA) and their branches the ICA originates from the common carotid, and each ICA gives off ophthalmic, posterior communicating and anterior choroidal arteries before dividing into anterior and middle cerebral arteries

ischemic hemorrhagic

mechanisms of stroke: 1) _____________: where the blood vessel is blocked, which can be thrombotic or embolic 2) _____________: where the blood vessel ruptures

primary sensation forebrain

more than a feeling: what we have just described is the detection of pain at its most basic level: is it there or not? this is referred to as ___________ sensation; it is the most basic level of a sensory experience; it's just perception perception, however, is not all there is to feeling; pain can also create emotions, cue memories, and elicit significant physiological responses like quickening your heart rate or dilating your eyes; how does this happen? from the sensory cortex, the perception of pain is shared with other parts of cortex and subcortical gray matter; because it's the cortex speaking, that information doesn't have to go through the thalamus to get there; the cortex shares the information with many structures, including those of the limbic system the limbic system is a group of structures within the _____brain that lie just above the brainstem, and plays a key role in emotions and memories; it's also involved in the emotional reactions that have to do with survival, such as sexual desire or self‐protection through fighting or escaping

1) the nervous system needs to be able to make muscles contract 2) those contractions should occur when you want and not when you don't 3) the contractions that add up to a complex movement should flow from one to another with fluidity and coordination

movement teaches us about shared processing: there are 3 major components to body movement, and to explain their relative contributions, let's use the analogy of lights on a sign you know those lights that move around the outside of a sign, like at a car wash or movie theater? the kind that seem to sort of chase around the edge? that movement needs three things: 1) the lights have to be able to power on 2) the lights have to power on and off in the right sequence at the right time 3) the transition from one light to the next needs to be smooth and coordinated those 3 features hold true for muscle contractions in movements; now describe them in those terms: 1) ... 2) ... 3) ... these 3 features of normal, healthy movement are carried out by three different nervous system circuits that work together, each contributing its own elements

glutamate γ-amino butyric acid (GABA) glycine

name 3 types of amino acid neurotransmitters

cholecystokinin substance P enkephalin somatostatin

name 4 types of neuropeptide neurotransmitters

ACh DA NE 5-HT histamine

name 5 types of amine neurotransmitters

dura mater ("tough mother") arachnoid mater pia mater

name the (3) layers of the meninges, from outer to inner

trigeminal nerve upper cervical nerves

neural innervation of the dura mater is important in the consideration of head pain: _________________: innervates the supratentorial region _________________: innervate the infratentorial region

1) the notochord is derived from mesoderm; SHH (sonic hedgehog); floor plate 2) floor plate; SHH; BMPs (bone morphogenetic proteins); roof plate

neural patterning: the spinal cord is organized to form motor neurons ventrally and sensory neurons dorsally because signaling molecules are secreted during neural patterning and divide the neural tube into dorsal and ventral regions 1) the notochord (derived from ______derm), is found ventral to the neural tube, and extends the entire length of the future vertebral column; it secretes the signaling molecule _______________, to instruct cells of the ventral neural tube to form the _____________: a secondary signaling center involved in neural patterning, devoid of neuroblasts 2) this _______ plate will secrete more ________ to influence cell fate, including the development of ventral motor neurons; the overlying surface ectoderm secretes _______________ to instruct cells of the dorsal neural tube to form the _________ plate (analogous to the other plate, but located on the dorsal surface of neural tube) this plate influences cell fate of dorsal sensory neurons

neural folds, neural crest cells

neural tube formation and neural crest cells, continued: by the end of the 3rd week of development, cells at the lateral edges proliferate and form elevated ___________, flanking the neural groove located at the midline; during this period, ___________ cells start to form

1) dorsal midline, neural tube 2) amniotic cavity; anterior and posterior neuropores 3) end of the 4th week, neurulation is complete 4) the cranial end of the neural tube dilates to form 3 brain vesicles: prosencephalon, mesencephalon, rhombencephalon 5) lumbar-sacral region

neural tube formation and neural crest cells, continued: 1) the neural folds gradually approach each other and then fuse at the _________ midline in cranial and caudal directions, respectively; this fusion results in a formation of the ______________, where small areas of the tube remain open at both ends 2) the open ends of the neural tube communicate with the ___________ cavity through the _____________________, until the fusion is completed 3) the anterior neuropore at the cranial end closes first on day 25, and the posterior neuropore at the caudal end follows two days later (day 27); by the end of the _________ week of development, the neural tube has completely closed, and the process of neurulation is complete and represents the developing CNS 4) the (cranial/caudal) end of the neural tube dilates and forms three brain vesicles: _______________ (forebrain), ______________ (midbrain), and ________________ (hindbrain) 5) the caudal end becomes the _____________ region of the embryo

1) neural crest cells 2) PNS

neural tube formation and neural crest cells, continued: in a dorsal view of the neural tube (left image), you can see the spinal cord and the region that will become the brain 1) during the neural tube closure, cells on the crest of the neural folds lose their contacts with the neuroectoderm, migrate, and form ___________ cells 2) these cells differentiate and contribute to the formation of the _________ some neural crest derivatives include, but are not limited to: melanocytes, schwann cells, adrenal medulla cells (chromaffin cells), dorsal root and cranial nerve ganglia and their sensory neurons, autonomic ganglia and their motor neurons, satellite cells, meningeal cells, and a variety of structures of the face the surface ectoderm is now dorsal (in image, colored green) to the neural tube

1) neuration: process by which the neural tube forms from the neural plate 2) CNS 3) by beginning of 3rd week, germ layers have formed; thicken the overlying ectoderm 4) epidermis of the skin, neural tube

neural tube formation and neural crest cells: 1) neurulation is the process where the neural ______ forms the neural ________ (see video link in coursepack) 2) the neural tube will give rise to the entire adult _________ 3) by the beginning of the _____ week of embryonic development, 3 germ layers, the endoderm, mesoderm and ectoderm become established; as soon as the notochord is formed, it begins to produce signaling molecules that thicken the overlying _____derm, and formation of the neural plate from the neuroectoderm 4) in a cross section through the developing embryo (right image), the ectoderm is subdivided into the surface ectoderm (colored green), which gives rise to the ________________, and the neuroectoderm which gives rise to the ______________ (colored yellow)

an axon and a dendritic spine of another neuron

neurochemical communication in the brain: synapses: a synapse between 2 neurons consists of a neuronal presynaptic membrane, a gap called the synaptic cleft, and a neuronal postsynaptic membrane neurons in the brain communicate by the release of chemical messengers (neurotransmitters) at synapses; an action potential causes presynaptic vesicles to fuse with the presynaptic membrane to then release neurotransmitters into the synaptic cleft the most abundant synapse in the CNS occurs between an __________ and a ________________ of another neuron; however, other synaptic relationships exist to provide alternate ways for neurons to communicate (e.g., axo-axonic, somato-axonic, somato-dendritic, and dendro-dendritic)

1) neural ectoderm (neuroectoderm), mesoderm 2) neural crest cells

neuronal cells (glial cells): glial cells are more numerous than neurons and can be thought of as the "glue" for neurons by providing support and structure the glial cells of the CNS are derived from _______________, except for microglial cells, which originate from ______________ glial cells of the PNS are derived from ________________ cells there are different types of glial cells with somewhat analogous but not identical functions (see table on next card)

amino acids and amines are also called "small molecule neurotransmitters" to differentiate them from the larger neuropeptides

neurotransmitter families: synaptic transmission uses molecules called neurotransmitters that either excite the postsynaptic neuron or inhibit it there are 3 major groups of neurotransmitters: amino acids, amines, and neuropeptides (~100 different peptides are known to be released by different populations of neurons in the brain) ___________ and ___________ are also called "small molecule neurotransmitters" to differentiate them from the larger _____________

1) neurotrophins (trophe: "nourishment") 2) neuron growth factor (NGF) note: other families of neurotrophins include brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell line-derived neurotrophic factor (GDNF)

neurotrophic factors: neurons are metabolically active and require nourishment (proteins) to maintain their differentiated properties 1) they obtain proteins from their targets and from glial cells called ____________ 2) during development, neurons are initially overproduced and compete for neurotrophins, and neurons that do not gain access to neurotrophins will eventually die; a well-known neurotrophin is ________________, which is released from target tissues; this is essential for the survival and differentiation of sympathetic neurons and sensory neurons certain neurotrophins are also important for repair of the nervous system, such as in spinal cord injury

1) brain 2) spinal cord

organization of the brain changes based on location: the arrangement of gray and white matter within the nervous system changes depending on where you are; here's an image from the Blumenfeld text that shows the different distributions of gray and white matter in the brain, brainstem, and spinal cord 1) in the (brain/spinal cord), most of the gray matter is either on the outside (cortex) or deep inside as sub-cortical structures 2) in the (brain/spinal cord), the white matter is on the outside; why is this? we don't really know

1) spinal nerves technically part of the PNS 2) dorsal roots: carry the afferent fibers 3) ventral roots: carry efferent fibers from these cell bodies in the ventral horn, which contains motor neuron cell bodies [also called spinal motor neurons or lower motor neurons (LMNs)]

overview of the spinal cord, continued: 1) though technically part of the (CNS/PNS), the spinal nerves define segments of the spinal cord; forming where the dorsal and ventral roots merge, they contain nerve fibers carrying BOTH afferent information (incoming information; think "afferent = arrives") and efferent information (information that is exiting; think "efferent = exits") 2) the dorsal roots carry the ____________ fibers of cell bodies located in the dorsal root ganglia; within the spinal cord, the dorsal horn (gray matter) is the site of termination of many of these neurons, while others pass through on their way to the brain 3) the ventral roots contain _____________ fibers from cell bodies lying within the gray matter of the spinal cord, in a region called the "ventral horn"; the ventral horn contains _______________ cell bodies, whose axons travel in peripheral nerves and innervate skeletal muscle

the spinal cord has a central H-shaped core of gray matter, surrounded by large bundles of white matter containing axons

overview of the spinal cord: the spinal cord lies within the vertebral (spinal) canal of the vertebral column and is physically continuous with the lowest portion of the brainstem the spinal cord is used to connect the trunk and limbs to the brain and brainstem; it has a central, H‐shaped core of (gray/white) matter that runs almost the entire length (see diagram) surrounded by large bundles of (gray/white) matter containing axons going to and from the brain you could think of the spinal cord like a tall apartment building, with floors of gray matter stacked on top of each other and white matter elevators carrying information to and from each floor

5th Telencephalon, Diencephalon, Mesencephalon, Metencephalon, and Myelencephalon

primary and secondary embryonic vesicles, continued: during the _____ week of gestation, 5 secondary brain vesicles are formed, which are...

1) prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain) 2) 4th week

primary and secondary embryonic vesicles: 1) as the neural tube closes at the anterior neuropore, it forms 3 bulges known as primary brain vesicles, which are... 2) these 3 primary vesicles are present around the _____ week of gestation, and will develop into the main divisions, forming the brainstem and cerebral hemispheres

middle meningeal artery

primary blood supply of the dura mater

dorsal root ganglia (DRG)

primary sensory neurons, a type of pseudounipolar neuron, have their cell bodies in the...

meninges

protective coating or coverings of the brain, which is a series of membranes that separate the CNS parenchyma from the skull or vertebral columns, and are continuous over the brain and spinal cord

excitatory synapses produce a depolarization of the postsynaptic membrane, where inhibitory synapses produce a hyperpolarization of the postsynaptic membrane D1 receptors activate adenyl cyclase; D2 receptors: inhibit adenyl cyclase

receptors: the neurotransmitter/receptor complex of a synapse determines the postsynaptic potential of a cell excitatory synapses produce a _____polarization of the postsynaptic membrane (EPSP), where inhibitory synapses produce a _____polarization of the postsynaptic membrane (IPSP) there are often multiple receptor subtypes (located on different postsynaptic terminals) for a given small-molecule neurotransmitter (e.g., there are at least 7 subtypes of serotonin receptors and at least 5 subtypes of dopamine receptors) depending on the receptor subtype, neurotransmitters can have different actions at different synapses for example, dopamine can be either excitatory or inhibitory depending on the receptor on the postsynaptic cell (D__ receptors activate adenyl cyclase and D__ receptors inhibit adenyl cyclase)

tryptophan; raphe nuclei ("ridge" or "seam")

serotonin (5-HT) pathway: serotonin (5-HT) is synthesized from _______________; serotonergic neurons are found within the midline of the brainstem called the ___________ nuclei, which extends from the midbrain down to the medulla similar to NE neurons, the serotonergic neurons also have a widespread distribution in the CNS (cerebral hemispheres, cerebellum, spinal cord, and other regions of the brainstem), and are also involved in many behavioral and physiological processes firing of serotonergic neurons in the these raphe nuclei increases in the awake state and decreases during sleep; the major route of removal of serotonin from the synapse is by reuptake the blockage of serotonin reuptake (e.g. by SSRI drugs) is an important mechanism in the treatment of depression, anxiety, and obsessive-compulsive disorder (OCD)

glutamate

the most common excitatory neurotransmitter in the CNS

5) thalamus; cortex-to-cortex communication and smell are exempt from this rule, as is smell

some principles of neurobiology, continued: 5) if it's going up to the cortex, it's going through the __________ first; damage to this can result in a host of problems, which can be a clue that it is the site of the problem; ___________-to-___________ communication is exempt from this rule, though, as is __________ 6) the inputs and outputs of the brain are body-mapped; NOT all body maps in the nervous system are laid out the same way, but they do exist for all sensory and motor systems 7) shared processing is essential for the full effect; more on this later in the section on movement, but as you will see, even an intact circuit needs help from other intact circuits to create the full range of the human nervous system 8) lesions, lesions, lesions; neurology is all about being able to determine where in the nervous system things have gone wrong; an area of abnormal tissue is called a "lesion"; a lesion can be due to a stroke, tumor, stab wound, anything that makes the tissue at that site abnormal

1) circuit

some principles of neurobiology: studying pain helps reveal certain principles of neurobiology that will be helpful to understand the rest of the material, these include: 1) the functions of the nervous system rely on multiple, interconnected gray and white matter structures working together in a ________; no singular part of the nervous system is solely responsible for the perception of pain or any other stimulus; these circuits often require elements from both the CNS and PNS, and what they report can be modified in a number of ways; drawing circuits out is strongly recommended 2) because these functions require intact circuits, damaging any parts or the connections between parts means the circuit is broken and the overall function is damaged or lost; in order to get ice cream, it takes cows, farmers, truckers, chemists, chefs, packers, salespeople and roads to connect them all to you losing any one of those things means no ice cream (pain does not require cows, but the analogy hopefully stands); this means that if our patient finds they cannot feel pain from the upper arm, there are multiple options for sites where the problem might be

spina bifida cystica

spina bifida _______________: failure of vertebral arch fusion that does involves herniation of just meninges OR meninges and spinal cord through the vertebral arch defect the defect is covered by skin or a thin membrane

GABA

the most common inhibitory neurotransmitter in the CNS

spina bifida occulta

spina bifida ________________: failure of vertebral arch fusion, but no herniation of the meninges and/or spinal cord the site is covered by skin and marked by a tuft of hair, and recognized as a birthmark or dimple it's usually symptom free and clinically insignificant, but can be prone to trauma

infarct ischemic penumbra

stroke is the 5th leading cause of death, and costs the US healthcare system billions of dollars every year it's a form of cerebrovascular disease involving the disruption of blood supply 1) __________: area of dead cells 2) ____________________: area surrounding a core of dead cells, which is tissue at risk

dura and arachnoid maters bridging veins

subdural hematoma: this occurs between the __________ and _____________ maters, as a result of head trauma the brain, with attached arachnoid rotates in the skull, and bridging (arteries/veins) traveling to dural sinus are torn in plane of dural border cells this results in hemorrhage into that space; note in the radiologic image the presentation of a subdural hematoma

tripartite synapse

synapses, continued: in addition to the classic concept of information exchanged between pre- and post- synaptic neurons, glial cells can exchange information between an adjacent neuronal synapse and help regulate transmission the relationship between 2 synaptic neurons and an astrocyte is called a ________________, and it is the coordinated activity of neurons and glia for optimal brain functionality

neuromodulation diffusely, volume transmission

synaptic transmission was the original theory of information transfer in the CNS, but we now know that there are other mechanisms of communication between neurons another one is _________________, which is slow-acting, usually has prolonged effects, and can be thought of as "fine-tuning" the neural circuitry of an entire brain region neuromodulators spread _____________ (via _____________ transmission) throughout the brain into the general vicinity of a large population of neurons to cause either inhibition or excitation of presynaptic neurons certain neurotransmitters (e.g., acetylcholine, norepinephrine, dopamine, serotonin, histamine), neuropeptides, and hormones also act as neuromodulators in contrast to neurotransmission, neuromodulation does NOT cause the formation of EPSPs or IPSPs

satellite cells Schwann cells

the (2) glial cells that are located in the PNS

astrocytes oligodendrocytes microglia ependymal cells

the (4) glial cells that are located in the CNS

acellular

the CSF constituents are ____________, with no RBCs or WBCs, and include (don't need to memorize these): glucose K+ Na+ chloride calcium magnesium protein hormones oxygen lactate amino acids urea lipids neurotransmitters ammonia

cerebellum note: cerebellum: "little brain"

the ___________________ has its own white and gray matter and plays significant roles in the control of balance, body position, and movement in space; it exists just posterior to the pons and medulla

A.1) tight junctions of endothelial cells B.1) diffusion B.2) carrier mediated transport/diffusion

the blood-brain barrier (BBB): A) morphological basis: 1) includes ____________ junctions of endothelial cells 2) paucity of pinocytic vesicles 3) pericytes, perivascular microglia and astrocytic end-feet B) molecular movement: 1) ________________ of oxygen, CO2, and lipid-soluble molecules 2) ___________________ of glucose 3) also involves active transport

1) a conduit for fibers passing between the brain and the spinal cord 2) home to the lower motor neurons (LMNs) that control structures of the head and neck, along with sensory neurons that transmit sensation from those structures 3) home to many components involved in life-sustaining functions such as breathing, cardiac function, and consciousness

the brain stem: as we move up the long axis of the nervous system (sometimes called the "neuraxis") from the spinal cord, we come to the brainstem; the brainstem is composed of the midbrain, pons, and medulla, and is physically continuous with the spinal cord and the brain; these regions are shown in the image (this view is the medial surface of one half of the brain in sagittal view) the brainstem serves (3) broad functions:

1) the cortex is gray matter functions: 1) frontal lobe: motor cortex and/or executive functions 2) parietal lobe: somatosensory (body-sensation) cortex 3) temporal lobe: auditory cortex 4) occipital lobe: visual cortex

the brain: cerebrum (cerebral hemispheres/ forebrain) the brain has two cerebral hemispheres; the right and left hemispheres contain the same stuff and are physically identical, although functionally there are hemispheric differences for simpler functions like sensation and movement, each side of the brain is responsible for the opposite side of the body (the left hemisphere controls the right arm, for example) 1) the surface of each hemisphere is covered with a multi-layered sheet of (gray/white) matter called cortex; you can think of cortex as a bunch of flat-ish nuclei quilted together; the early anatomists, overwhelmed by the complexity of the brain, started breaking it down by certain functional properties of different anatomical areas 2) today, we know these areas as the lobes; four of these lobes are shown in the image, with the following major regions related to motor and sensory functions; the functions used to characterize these lobes are far from the only ones subserved by those regions, but it's an okay place to start: A) frontal lobe: _____________ cortex and/or _________________ functions B) parietal lobe: ______________________ cortex C) temporal lobe: ____________ cortex D) occipital lobe: ____________ cortex

1) ridges: gyri; valleys: sulci 2) the cortex is connected to itself/other structures via vast network of axons with an inner core of white matter; the corpus callosum is composed of white matter

the brain: cerebrum (cerebral hemispheres/ forebrain), continued: 1) each hemisphere has its wrinkled cortex divided into ridges (called _____________) and valleys (called ______________) 2) the cortex is connected to itself and other structures by a vast network of axons comprising an inner core of (gray/white) matter; this includes the corpus callosum, a large (gray/white) matter superhighway connecting the two hemispheres other areas of subcortical (meaning physically inside of the cortex) gray matter are found like islands within the white matter core; these subcortical gray matter structures help the cortex do its many jobs

1) diencephalon 2) the thalamus is basically the executive assistant to the cortex 3) the hypothalamus is involved in maintaining homeostasis, linking the nervous system with the endocrine system, and regulates output of the autonomic nervous system

the brain: cerebrum (cerebral hemispheres/ forebrain), continued: 1) examples of subcortical gray matter include the thalamus (shown in green) and hypothalamus (blue), which are part of a collection of subcortical structures called the _______________ 2) the thalamus is an egg-shaped structure found on either side of the midline just above the top of the brainstem; you have a right thalamus and a left thalamus; any information going into the cerebral cortex must first pass through the thalamus; it's basically the __________________ to the cortex, and plays an important part in sensory, motor, and cognitive functions 3) the hypothalamus, found just below and in front of the thalamus, is involved in maintaining _____________; it links the nervous system with the ___________ system (through regulation of hormones secreted from the pituitary gland) and it regulates output of the _____________ nervous system (which controls organ function) the hypothalamus also receives incoming sensory signals, coordinating the body's response to changes in the internal or external environments

regulate movement

the brain: cerebrum (cerebral hemispheres/ forebrain), continued: the basal ganglia (more correctly named the basal nuclei; brown in the diagram) are another important example of subcortical gray matter; this collection of structures talks to each other and to cortex the basal ganglia are closely connected with the cortex, thalamus, and other structures in neuronal circuits that regulate _____________; the basal ganglia are also involved in cognitive and emotional functions

midbrain pons medulla

the brainstem is composed of what (3) structures?

falx cerebri tentorium cerebelli falx cerebelli

the dura mater has (3) dural folds

dura mater: pachmeninges arachnoid and pia mater: leptomeninges (or just meninges)

the dura mater is also known as the __________meninges, while the arachnoid and pia mater form the __________meninges

periosteal and meningeal layers of the dura

the dural venous sinuses are located between the ______________ and _____________ layers of the dura mater

1) the amygdala and hippocampus play roles in learning from pain, as well as recalling whether you've felt something similar from similar circumstances 2) the cingulate gyrus helps create the emotions you feel about a stimuli 3) hypothalamus

the limbic system, continued: 1) these structures help contextualize stimuli: for example, the ____________ and _____________ play roles in learning from pain as well as recalling whether you've felt similar pain from similar circumstances before 2) the ____________ helps create the emotions you feel about stimuli, which might be more evident in the loss of a loved one than a punch in the arm 3) these parts of the brain can then evoke changes in the body as needed by controlling the _____________; this can, for example, evoke the "fight or flight" response through the autonomic nervous system; hence the quickening heart rate or pupillary dilation

1) the limbic system is a group of structures within the forebrain

the limbic system: 1) how do you feel emotionally about a thing that you experience? how do those emotions correspond to changes in your physiology? do your palms sweat? does a particular smell from your childhood make you feel relaxed? the limbic system, a group of structures within the ______________, plays a key role in connecting stimuli with emotions and memories it is also involved in the emotional reactions that have to do with survival, such as sexual desire or self‐protection through fighting or escaping; in the diagram, several main parts of the limbic system are colored blue; these will be discussed in later material in much more detail, but the main ones are the hippocampus (also called hippocampal formation), amygdala, and the cingulate gyrus

multipolar

this is the most common type of neuron here, dendrites radiate from the neuron cell body, along with one axon interneurons, motor neurons, and secondary sensory neurons in the dorsal horns of the spinal cord are examples of these types of neurons

false: in the brain, most of the gray matter is either on the outside (cortex) or deep inside as sub-cortical structures; in the spinal cord, the white matter is on the outside

true or false: in the brain, most of the white matter is either on the outside (cortex) or deep inside as sub-cortical structures; in the spinal cord, the white matter is on the inside

false, most is located in the ventricular system

true or false: most CSF is located in the subarachnoid space (SAS)

true

true or false: synaptic transmission causes EPSPs and IPSPs, but neuromodulation doesn't

sensory (afferent) neurons

type of neuron which collects sensory information from somatic and visceral sensory organs within the PNS to be processed by the CNS for example, somatic sensory (somatosensory) neurons convey information such as light touch, pain, and temperature from the skin, and proprioceptive information from the body, and then that information is brought into the CNS to be processed visceral sensory (viscerosensory) neurons convey information such as chemical or mechanical changes from visceral effector organs into the CNS to be processed

interneurons

type of neurons which are found exclusively in the CNS and are situated between motor and sensory neurons there are local versions of these with short axons, or projection ones with long axons, which communicate with neurons at more distant brain regions an example of one location with these is in the spinal cord gray matter, between a motor and sensory neuron, completing a reflex arc

motor (efferent) neurons

type of neurons which carry motor information from the CNS and then out to somatic or visceral effector organs in the PNS somatic motor (somatomotor) neurons innervate skeletal m., and visceral motor (visceromotor, autonomic) neurons innervate smooth m., cardiac m., and glands.

meningocele

type of spina bifida involving herniation of the meninges and CSF through the bony defect, but not the spinal cord

meningomyelocele (also known as myelomeningocele)

type of spina bifida involving protrusion of the meninges, CSF, and spinal cord and/or cauda equina through the bony defect the overlying skin is either thin or absent; symptoms and loss of function depend on location (usually lumbar) paralysis of the lower limbs, bladder, and rectum are possible

myeloschisis

type of spina bifida which is the most severe, involving a series of wide-open vertebrae often associated with open neural tube, resulting from failure of neural folds to close it results in permanent paralysis or weakness of lower limbs in addition to other complications

1) 3rd and 5th months, astrocyte "scaffolds" 2) sonic hedgehog (SHH) concentrations 3) pruning

types of developmental events and timeline after formation of secondary embryonic vesicles, continued: B) neuronal migration and survival: 1) the peak time period for neuronal migration overlaps considerably with proliferation, during the ____ and _____ months of gestation; neurons develop axons and dendrites and migrate to their correct locations by using ____________ "scaffolds" 2) generally, each neuron sends out one axon, which elongates until it reaches a target (either another neuron or an effector tissue); the process of finding the target is guided by chemical and physical signals provided by the environment, including ______________________ concentrations the growth cone of the developing axon sends out exploratory fingers and retracts those that do not meet a favorable physical or chemical signal from the surrounding tissue; only about 1/2 of the neurons that are produced during development survive in the mature brain; those that die likely do so because they have not received neurotrophic (trophic) signals or they have not been sufficiently active to keep them alive 3) most of the cells that die do so through a process of "programmed cell death" called apoptosis; thus, the process of overproduction of neurons and ________ is an important part of neural development

1) 8 weeks 2) trophic factors 3) astrocytes; synaptic pruning

types of developmental events and timeline after formation of secondary embryonic vesicles, continued: C) synaptogenesis and synaptic pruning: 1) synapses begin about _____ weeks gestation and continues as neurons proliferate, differentiate and migrate; when axons arrive at a target that has the appropriate physical and chemical makeup, they establish a synaptic contact; whether or not the synaptic contact will persist depends upon several factors including: 1) activation of the neurons, 2) chemical signals from surrounding cells, 3) and chemical signals coming back from the target cells 2) these chemical signals have been important for the growth and guidance of the neurons and now continue to be important for survival of the neuron; these chemicals are called ____________ factors and they are important not only during development but also for the maintenance of neurons throughout life 3) ____________ also play a role in determination of synaptic connections; many synapses that form are subsequently lost and may be replaced by new synapses; _________________ refers to the process of reducing the overall number of neuron processes and synapses during development, with the most efficient synaptic configurations surviving

6 months gestation, 1st year after birth oligodendrocytes

types of developmental events and timeline after formation of secondary embryonic vesicles, continued: D) myelination: CNS myelination begins at about ___ months gestation, peaks during the first _____ after birth, and continues into adulthood the myelin sheaths in the CNS are formed by ___________________ and provides a more rapid conduction of axon potentials along the axon

1) 3rd and 4th months 2) subventricular zone

types of developmental events and timeline after formation of secondary embryonic vesicles: A) neuronal proliferation: 1) the peak time period for neuronal proliferation is the _____ and _____ months of gestation 2) most neuronal proliferation in the forebrain occurs in a region called the ____________ zone, adjacent to the lateral ventricles

ex vacuo hydrocephalus

types of hydrocephalus, continued: ________________: where ventricular enlargement is secondary to cerebral atrophy

communicating non-communicating

types of hydrocephalus: 1) ________________: where the ventricular system still communicates with the SAS, but there's blockage of CSF resorption in the SAS 2) ________________: the ventricular system does NOT communicate with the SAS, and there's a block between the lateral ventricles and the SAS; this involves: A) foramen of Monro B) 3rd ventricle C) aqueduct D) 4th ventricle E) exit foramina from the 4th ventricle

hippocampus (hippocampal formation) amygdala cingulate gyrus

what are (3) main parts of the limbic system?