Central Nervous System

Front 1

Forebrain

Back 1

(prosencephalon)

telencephalon: includes the cerebrum, hippocampus, basal ganglia, amygdala

diencephalon: thalamus, hypothalamus, subthalamus, epithalamus. Major motor and sensory tracts synapse here: act as an interactive site between the CNS and the endocrine system, as well as complementing the limbic system.

Front 2

Midbrain

Back 2

(mesencephalon)

tectum: superior and inferior colliculi

Tegmentum: cerebral aqueduct, periaqueductal gray, reticular formation, substantia nigra, red nucleus

Front 3

Hindbrain

Back 3

(rhombencephalon)

metencephalon: cerebellum, pons

myelencephalon: medulla oblongata

Front 4

Brainstem

Back 4

midbrain, pons, medulla oblongata

Front 5

Gray matter

Back 5

consists of unmyelinated neurons and contains capillaries, glial cells, cell bodies, and dendrites

Front 6

White matter

Back 6

consists of myelinated axons and contains nerve fibers without any dendrites

divided into anterior, lateral, and dorsal columns

Front 7

Telencephalon: Cerebrum

Back 7

Major portion of the brain. Two hemispheres joined at the bottom of the white matter, corpus callosum which relays info to each side. Outer surface is gray matter, inner is white matter.

Fissures: interhemispheric and sylvian

Sulci: central, parieto-occipital, and calcarine sulcus.

Front 8

Cerebrum: Left vs. Right

Back 8

Left: language, sequence and perform mov, understand language, produce written and spoken language, analytical, controlled, logical, rational, mathematical calculations, express positive emotions, process verbally coded info in an organized logical sequenced manner.

Front 9

Cerebrum: Right vs. Left

Back 9

Right: Nonverbal processing, process information in a holistic manner, artistic abilities, general concept comprehension, hand-eye coordination, spatial relationships, kinesthetic awareness, understand music, understand nonverbal communication, mathematical reasoning, express negative emotions, body image awareness.

Front 10

Frontal Lobe of Cerebrum

Back 10

Fxn: voluntary mov (primary motor cortex/precentral gyrus), intellect, orientation; Broca's area (typically in the L hemisphere) includes speechc, concentration; personality, temper, judgement, reasoning, behavior, self-awareness, executive fxns.

Impairment: contra weakness, perseveration, inattention, personality changes, antisocial behavior, impaired concentration, apathy, Broca's aphasia (expressive deficits) delayed or poor initation, emotional lability.

Front 11

Parietal

Back 11

Fxn: associated with sensation of touch, kinesthesia, perception of vibration, and temp; info from other areas of the brain regarding hearing, vision, motor, sensory and memory; provides meaning for objects, interprets language and words, spatial and visual perception.

Impairment: dominant hemisphere (L) will show agraphia, alexia, agnosia; non-dominant (R) will show dressing apraxia, constructional apraxia, anosognosia; contra sensory deficits; impaired language comprehension; impaired taste

Front 12

Temporal

Back 12

Fxn: primary auditory processing and olfaction; Wernicke's area (typically L) allows ability to understand and produce meaningful speech, verbal and general memory, assists with understanding language; the rear of the temp lobe enables humans to interpret other peoples emotions and reactions

Impairments: learning deficits; Wernicke's aphasia (receptive deficits); antisocial, agressive behaviors; difficulty with facial recognition; difficulty with memory and memory loss; inability to categorize objects.

Front 13

Occipital

Back 13

Fxn: main processing center for visual information; processes visual information regarding colors, light and shapes; judgment of distance, seeing in three dimensions.

Impairments: homonymous hemianopsia; impaired extraocular muscle movemnt and visual deficits; impaired color recognition; reading and writing impairment; cortical blindness with bilateral lobe involvement

Front 14

Telencephalon: Hippocampus

Back 14

Deeply embedded within the lower temporal lobe.

Responsible for the process of forming and storing new memories of one's personal history and other declarative memory.

Learning language.

"Memory Indexer" sends memories to appropriate areas of the cerebral hemispheres for long-term storage and retrieves memories when needed.

Front 15

Telencephalon: Basal Ganglia

Back 15

Gray matter masses located deep within the white matter of the cerebrum: caudate, putamen, globus pallidus, substantia nigra, and subthalamic nuclei.

Collectively are responsible for boluntary movement, regulation of autonomic movement, posture, muscle tone, and control of motor responses.

Dysfunction: parkinsons, huntingtons, tourettes, ADD, OCD and many addictions.

Front 16

Telencephalon: Amygdala

Back 16

Small, almond shaped, located in the temporal lobes of each hemisphere.

Emotional and social processing.

Involved in fear and pleasure responses, arousal, processing of memory and the formation of emotional memories.

Front 17

Diencephalon: Thalamus

Back 17

Relay, or processing station, for the majority of the information that goes to the cerebral cortex. Coordinates sensory perception and mov with other parts of the brain and spinal cord that also have a role in sensation and movement. Receives info from the cerebellum, basal ganglia, and all sensory pathways except the olfactory tract. The thalamus then relays the info to the appropriate association cortex. Thalamic pain syndrome may occur if there is damage (contralateral side of the lesion experiences spontaneous pain).

Front 18

Diencephalon: Hypothalamus

Back 18

Receives and integrates info from the ANS and assists in regulating hormones. Also controls hunger, thirst, sexual behavior, and sleeping. Regulates body temp, the adrenal glands, the pituitary gland and many other vital activities.

Lesions can produce obesity, sexual disinterest, poor temperature control and diabetes insipidus.

Front 19

Diencephalon: Subthalamus

Back 19

Regulates movements produced by skeletal muscles.

Has associations with the basal ganglia nad the substantia nigra.

Front 20

Diencephalon: Epithalamus

Back 20

Represented by the pineal gland. Glad secretes melatonin and is involved in circadian rhythms, the internal clock, selected regulation fo motor pathways, and emotions.

Associated with the limbic system and the basal ganglia.

Front 21

Midbrain (Mesencephalon)

Back 21

Component of brain stem, located at the base of the brain above the SC. Connects the forebrain the the hindbrain. Fxns as a large area for information passing from the cerebrum, cerebellum, and SC. Also a reflex center for visual, auditory and tactile responses.

Tectum: superior and inferior colliculi

Tegmentum: cerebral aqueduct, periaqueductal gray, reticular formation, substantia nigra, red nucleus

Front 22

Hindbrain (Rhombencephalon): Cerebellum

Back 22

Fine tuning of movement and assists with maintaining posture and balance by controlling mm tone and positioning of the extremities in space.

Controls the ability to perform rapid alternating movements. Two hemispheres of gray matter, divided into 3 lobes: anterior, posterior, and flocculonodular lobes with the fourth ventricle lying anterior to the lobes. Damage to one side will produce ipsilateral damage. Cerebellar lesions may produce ataxia, nystagmus, tremor, hypermetria, poor coordination, and deficits in postural reflexes, balance, equilibrium depending on the area.

Front 23

Hindbrain (Rhombencephalon): Pons

Back 23

Below the midbrain and superior to the medulla oblongata.

Assists with regulation of respiration rate and is associated with the orientation of the head in relation to visual and auditory stimuli. CN V through VIII originate from the pons.

Front 24

Hindbrain (Rhombencephalon):

Medulla Oblongata

Back 24

Connects to the pons superiorly and the SC inferiorly. White matter on the surface and gray matter on the interior.

Influences ANS activity and the regulation of respiration and heart rate. Reflex centers for vomiting, coughing and sneezing are found here.

Damage to motor tracts crossing within the medulla produces contralateral impairment.

Also responsible for relaying somatic sensory information from internal organs and for the control of arousal and sleep. CN IX X XI and XII originate here.

Front 25

Brainstem

Back 25

Midbrain, pons, medulla oblongata.

Relay station.

Primitive fxns essential for survival: regulation of heart rate and RR.

Reticular activating system is found within the midbrain, pons and medulla and a portion of the thalamus. Severe damage to the brainstem will often result in brain death.

Majority of cranial nerves originate here.

Front 26

Blood Supply

Back 26

Brains blood supply consists of the two internal carotid arteries and the two vertebral arteries. The branches of the main arteries form the circle of Willis.

Front 27

ACA

Back 27

Blood supply: anterior frontal lobe, medial surface of the frontal and parietal lobe.

Expected impairment: contralateral LE motor and sensory involvement, loss of bowel bladder, loss of behavioral inhibition, significant mental changes, neglect, aphasia, apraxia and agraphia, perserveration, akinetic mutism with significant bilateral involvement.

Front 28

MCA

Back 28

Blood supply: most of the outer cerebrum, basal ganglia, posterior and anterior internal capsule, putamen, pallidum, lentiform nucleus.

Expected impairment: most common site of a CVA, Wernicke's aphasia in dominant hemisphere, homonymous hemianopsia, apraxia, flat affect with R hemishphere damage, contra weakness and sensory loss of face and UE with less LE involvement, impaired spatial relations, anosognosia in non-dominant hemisphere, impaired body schema.

Front 29

PCA

Back 29

Blood supply: portion of midbrain, subthalmic nucleus, basal nucleus, thalamus, inferior temporal lobe, occipital and occipitoparietal cortices.

Expected impairment: contralateral pain and temp sensory loss, contra hemiplegia (central area), mild hemiparesis, ataxia, athetosis or choreiform movement, quality of movement is impaired, thalamic pain syndrome, anomia, prosopagnosia with occipital infarct, hemiballismus, visual agnosia, homonymous hemianopsia, memory impairment, alexia, dyslexia, cortical blindness from bilateral involvement.

Front 30

Vertebral-basilar Artery

Back 30

Blood supply: lateral aspect of pons and midbrain together with superior surface of cerebellum; cerebellum; medulla (posterior infereior cerebellar a); pons (branches of basilar); midbrain and thalamus (posterior cerebral a); occipital cortex (posterior cerebral a, basilar a).

Expected impairments: loss of conciousness, hemiplegia or teraplegia, comatose or vegetative state, inability to speak, locked-in syndrome, vertigo, nystagmus, dysphagia, dysarthria, syncope, ataxia

Front 31

Meninges

Back 31

Provide protection from contusion and infection. Blood vessels and CSF within the meninges

Dura mater: outer most, four folds, lines the periosteum of the skull and protects the brain

Arachnoid mater: middle: impermeable; surrounds the brain in a loose manner

Pia mater: innermost; covers the contours of the brain; forms the choroid plexus in the ventricular system

Front 32

Dural Spaces

Back 32

Epidural space: between skull and outer dura mater

Subdural: between dura and arachnoid

Subarachnoid space: between arachnoid and pia mater that contains CSF and the circulatory system for the cerebral cortex

Front 33

Ventricular System

Back 33

Designed to protect and nourish the brain. Comprised of four fluid-filled cavities called ventricles and multiple foramina that allow the passage of cerebrospinal fluid. Each ventricle contains specialized tissue called choroid plexus.

Excess CSF in brain= hydrocephalus

Excess fluid in SC= syringomyelia

CSF produced constantly with a yield of 500-700ml/day

Front 34

Blood Brain Barrier

Back 34

Consists of the meninges, protective glial cells, and capillary beds of the brain. Responsible for the exchange of nutrients between the central nervous system and the vascular system.

Front 35

Spinal Cord

Back 35

White and gray matter, largest amount of gray matter found within the L/s.

Vertebral A. forms the anterior spinal artery and two posterior spinal arteries that will surround the cord.

Each spinal nerve contains a dorsal root (sensory) with afferent fibers and a ventral root (motor) with efferent fibers.

Front 36

SC: Ascending Tracts

Back 36

Ascending in the white matter of the spinal cord arise either from cells of spinal ganglia or from intrinsic neurons within the gray matter that receive primary sensory input. Ascending tracts relay sensory feedback to the cerebrum and cerebellum.

Front 37

SC: Ascending Tract- Fasciculus cuneatus (posterior or dorsal column)

Back 37

sensory tract for the trunk, neck, and UE proprioception, vibration, two point discrimination and graphesthesia.

Front 38

SC: Ascending Tract- Fasciculus gracilis (posterior or dorsal column)

Back 38

sensory tract for the trunk and LE proprioception, two-point discrimination, vibration, and graphesthesia.

Front 39

SC: Ascending Tract- Spinocerebellar tract (dorsal)

Back 39

sensory tract that ascends to the cerebellum for ipsilateral subconscious proprioception, tension in mm, joint sense, and posture of the trunk and lower extremities

Front 40

SC: Ascending Tract- Spinocerebellar tract (ventral)

Back 40

sensory tract that ascends to the cerebellum, some fibers crossing with subsequent recrossing at the level of the pons for ipsilateral subconscious proprioception, tension in mm, joint sense, and posture of the trunk, UE, and LE

Front 41

SC: Ascending Tract- Spino-olivary tract

Back 41

ascends to the cerebellum and relays information from cutaneous and proprioceptive organs

Front 42

SC: Ascending Tract- Spinoreticular tract

Back 42

the afferetn pathway for the reticular fomrmation that influences levels of consciousness

Front 43

SC: Ascending Tract- Spinothalamic tract (anterior)

Back 43

sensory tract for light touch and pressure

Front 44

SC: Ascending Tract- Spinothalamic tract (lateral)

Back 44

sensory tract for pain and temperature sensation

Front 45

SC: Descending Tracts

Back 45

Voluntary motor function, mm tone, reflexes and equilibrium, visceral innervation, and modulation of ascending sensory signals.

Front 46

SC: Descending Tracts- Corticospinal tract (anterior)

Back 46

pyramidal motor tract responsible for ipsilateral voluntary, discrete, and skilled movements

Front 47

SC: Descending Tract- Corticospinal tract (lateral)

Back 47

pyramidal motor tract responsible for contralateral voluntary fine movements

**damage to either of the corticospinal tracts results in a positive babinski reflex, absent superficial abdominal reflex and cremasteric reflex, and the loss of fine motor or skilled voluntary movement

Front 48

SC: Descending Tract- Reticulospinal tract

Back 48

extrapyramidal motor tract responsible for facilitation or inhibition of voluntary and reflex activity through the influence on alpha and gamma motor neurons

Front 49

SC: Descending Tract- Rubrospinal tract

Back 49

extrapyramidal motor tract responsible for motor input of gross postural tone, facilitating activitiy of flexor mm, and inhibiting the activity of extensor mm

Front 50

SC: Descending Tract- Tectospinal tract

Back 50

extrapyramidal motor tract responsible for contralateral postural mm tone associated with auditory/visual stimuli

Front 51

SC: Descending Tract- Vestibulospinal tract

Back 51

extrapyramidal motor tract responsible for ipsilateral gross postural adjustments subsequent to head movements, facilitating activity of the extensor mm and inhibiting activity of the flexor mm.

Front 52

Damage to any SC: Descending Tracts that are extrapyramidal

Back 52

significant paralysis, hypertonicity, exaggerated DTR, and clasp-knife reaction

Front 53

Brown-Sequard's Syndrome

Back 53

Incomplete lesion typically caused by a stab wound. Will produce: paralysis and loss of vibratory sense and position sense on the same side as the lesion due to the damage to the cortiospinal tracts and dorsal columns. Loss of pain and temp on the opposite side of the lesion from damage to the lateral spinothalamic tract.