Brainstem part 2 Flashcards Preview

Intro to Neuro > Brainstem part 2 > Flashcards

Flashcards in Brainstem part 2 Deck (78):
1

Reticular Formation (what is it)

large diffuse group of tracts and nuclei

2

Reticular Formation (functions)

~integration of sensory input and to organize generalize response to that input
~somatic motor function- via reticulospinal motor pathways
~alertness and consciousness via the ascending reticular activating system
~pain control- Raphe and periaqueductal gray region

3

ARAS (what does it stand for)

ascending reticular activating system

4

Anatomy of the reticular formation serves (_____) integrations function (and details about this)

(sensory)
~neurons have large highly overlapping dendritic trees
~dendritic trees oriented perpendicular to long axis of brainstem
~as axons of the long ascending and descending tracts transverse the brainstem & have collaterals that intermingle with the neurons of the reticular formation
~each neuron receives information from a wide variety of sources

5

Neurons receives information from a wide variety of sources (details)

~one source may dominate input to each neuron but each neuron probably receives both visceral & somatic input and both motor & sensory input

6

Wide spread output with each reticular formation neuron collateral onto______ other neurons

> 25,000 other neurons
~particularly ascending fibers of the reticular activating system to the cerebral cortex

7

Reticulospinal Pathways

Medial (pontine) and Lateral (medullary)

8

Medial reticulospinal pathway

(pontine)
~arises from oral and causal pontine reticular nuclei
~excites postural muscle to produce a postural set

9

Lateral reticulospinal pathway

(medullary)
~arises from nucleus gigantocellularis reticular nucleus of the medulla
~inhibits postural muscles to get ready for movement

10

Ascending Reticular Activating System

Cholinergic (ACh) Component and Adrenergic (NE) Component

11

Cholinergic (ACh) Component

~Arise from dorsal tegmental nucleus & pedunculopontine nucleus
~important in wakeful and REM sleep states

12

Adrenergic (NE) Component

~arises from locus cerueus
~important in wakeful and slow-wave sleep states

13

Descending Pain Control Pathways

Serotongic (5-HT), Adrenergic (NE), Enkephalinergic

14

Serotongic (5-HT) Component

~Arises from midbrain, prontine raphe nuclei, & nucleus raphe magnus of the medulla
~Descend directly to the spinal cord to the inhibit nociceptive afferents

15

Adrenergic (NE)

~arises from the locus ceruleus
~descend directly to the spinal cord to inhibit nociceptive afferents

16

Enkephalinergic

~Arises from midbrain, periaqueductal grey
~descends directly to spinal cord and relays through raphe nuclei to inhibit nociceptive afferents

17

CN I: Olfactory Nerve

~receptor cells in olfactory muscosa ~olfactory nerve penetrates cribriform plates of ethmoid bone
~relayed by mitral cells of olfactory bulb whose axons form the olfactory tract
~olfactory tract axons end primary olfactory cortex of medial temporal lobe- pyriform area (periamygdalar &perihippocampal)
~projecctions to amygdala, hypothalamus, thalamus, hippocampus, & orbitofrontal cortex as well

18

For CN I, the receptor cells are in

olfactory muscosa

19

For CN I, the Olfactory nerve penetrates

cribriform plate of ethmoid bone

20

For CN I, the olfactory tract ends

primarily in primary olfactory cortex of medial temporal lobe

21

For CN I, projections to

amygdala, hypothalamus, thalamus, hippocampus, and orbitofrontal cortex

22

CN I: Olfactory Nerve (what does it to)

~sense of smell
~anosmia (inability to smell

23

Anosmia may occur with:

~common cold
~trauma to face
~degenerative neural diseases such as Parkinson's & Alzheimer's Diseases

24

CN II: Optic Nerve

~ Optic nerve arises from ganglion cells of retina (realty CNS tissue)
~Fibers from nasal (medial) retinal field decussate to opposite side in optic chiasm while fibers from temporal (lateral) retinal field stay ipsilateral
~Optic tract extends from chiasm to the geniculate nucleus of the thalamus
~thalamus axons radiate to the primary visual cortex

25

For CN II, optic nerve arises from

ganglion cells of retina

26

For CN II, optic tracts extends

from optic chiasm to the geniculate nucleus of the thalamus

27

For CN II, the thalamuc axons radiates to

the primary visual cortex

28

For CN II, damage to the optic nerve:

~singe eye (monocular) vision lost

29

For CH II, damage to the optic chiasm:

~loss of peripheral vision (bitemporal hemianopsia)

30

For CN II, damage to the optic tract and later in pathways,

~loss of contralateral visual field (contralateral homomynous hemianopsia)

31

CN III: Oculomotor Nerve

~ arises from medial ventral surface of midbrain
~oculomotor nuclei
~Innervated superior, medual, & inferior rectus and inferior oblique muscles, levator palpebrae
~parasympathetic control of pupillary sphincter and ciliary body for pupillary constriction & near vision lens accommodation respectively

32

For CN III, arises from

medial ventral surface of midbrain

33

For CN III, the oculomotor nuclei

~gives rise to the axons form the oculomotor nerve the come from the nuclear complex located in the dorsal midbrain tegmentum just ventral to the periaquductal gray
~Complex is made up of two parts: Oculomotor nucleus – LMN (somatic motor) & Edinger-Westphal nucleus (visceral motor)

34

For CN III, innervates

~superior rectus (elevation)
~medial rectus (adduction)
~inferior rectus (depression)
~inferior oblique (lateral rotation)
~levator palpebrae (raise eyelid)

35

For CN III, parasympathetic control

pupillary sphincter and ciliary body for pupillary constriction & near vision lens accommodation respectively

36

Damage to CN III

(oculomotor ophthalamoplegia)
~lateral strabismus
~Ptosis

37

Lateral strabismus

unopposed lateral rectus (CN VI)

38

Ptosis

drooping eyelid and compensation with frontalis contraction so raised eyebrow & wrinkled forehead

39

CN IV: Trochlear Nerve

~trochlear nucleus in midbrain caudal to oculomotor nucleus & ventral to periaqueductal gray
~only cranial nerve to exit the dorsal brainstem
~innervates the superior oblique
~produces intorsion (medial rotation)

40

For CN IV, arises

~just caudal to the inferior colliculus
~ from lower motor meurons located in the trochlear nucleus in midbrain caudal to oculomotor nucleus & ventral to periaqueductal gray

41

For CN IV, exits

dorsal brainstem (id the only cranial nerve to exit the dorsal brainstem)

42

For CN IV, innervates

superior oblique extraocular eye muscles (procures intorsion- medial rotation)

43

For CN IV, damage

(trochlear ophthalamoplegia)
~paresis/paralysis of superior oblique
~eye moves up and lateral and extortion
~head tilt to unaffected side to reduce diplopia (double vision)

44

CN VI: Abducens nerve

~Abducens nucleus located in caudal pons
~nerve exits medially at pontomedullary junction
~innervates the lateral rectus
~produces ocular abduction

45

For CN VI, arises from

lower motor neurons of the abducens nucleus locates in causal pons

46

For CN VI, exits

ventrl brainstem medially at pontomeduallary junction

47

For CN VI, innervates

lateral rectus, which produces ocular abduction (lateral movement of the eyes)

48

Damage of the CN VI

Produces cross eyed appearance due to lack of opposition of medial rectus muscles (innervated by CN III)

49

CN V: Trigeminal Nerve

~general sensory of face and motor muscle of mastication
~3 sensory division (ophthalmic- V1, Maxillary- V2, Mandibular- V3)
~motor division (mandibular- V3)
~has a 3 neuron sensory pathway to cerebral cortex

50

For CN V, the sensory divisions

Ophthalmic (V1)
Maxillary (V2)
Mandibular (V3)

51

For CN V, the motor divisions

Mandibular (V3)

52

For CN V, neural sensory pathways to the _____

(cerebral cortex)
~Primary (1*) sensory neuron is the trigeminal nerve primary afferent neuron with its cell bodies in trigeminal sensory ganglion
~Relay: the primary end on the secondary (2*) sensory neuron whose cell bodies are either chief sensory nucleus or spinal nucleus of CN V
~Tertiary (3*)- the secondary neurons of the pathways in either chief sensory nucleus or the spinal nucleus of CN V send their axons via trigeminothalamic tract to 3* sensory neurons whose cell bodies are in the ventral posterior medial (VPM) nucleus of thalamus
**these tertiary neurons of the 3 neuron sensory pathway in the VPM nucleus of thalamic have axons which project to primary somatosensory cortex

53

chief sensory nucleus:

for somatosensations of touch and pressure and the spinal nucleus of V for the somatosensation of pain and temperature

54

For CN V, the ______ neurons of muscles of ______ are in motor nucleus of CN V

(Lower motor) neurons {LMN} of muscles of (mastication) are in motor nucleus of CN V

55

For CN V, most common form of damage

Neuralgia (is the most common form of pathology)
~sometimes incorrectly called tic doulourex (which is only the facial spasms associated with the condition)
~characterized by severe shocking or stabbing facial pain

56

CN VII: Facial Nerve

~arises from brainstem laterally at the pontomedullary junction
~function include: general sensory, special sensory, somatic motor, parasympathetic efferent
~

57

For CN VII, arises

from brainstem laterally at the pontomedullary junction

58

For CN VII, functions

~general sensory: external ear & tympanic membrane
~special sensory: taste from anterior 2/3rd tongue (salty, sweet, or sour)
~somatic motor: muscle of facial expressions & stapedius
~parasympathetic efferents: to lacrimal glands and submandibular & sublingual salivary glands

59

For CN VII, damage

Bell's Palsy
~is the most characterized by the loss of voluntary control of the muscles ipsilateral (on the same side) as the damaged nerve

60

CN VIII, Vestibulocochlear Nerve

~Special Sensory Convey: vestibular (balance/ equilibrium) information & Cochlear (hearing/ auditory) information
~enters brainstem at pontomedullary junction very laterally
~involved in both balance and auditory reflexes as well as cognitive awareness of movement and balance and sounds

61

For CN VIII, special sensory conveys

~Vestibular (balance/ equilibrium) information
~Cochlear (hearing/ auditory) information

62

For CN VIII, enters

brainstem at pontomedullary junction laterally

63

For CN VIII, primary afferents arises

from neurons in the inner ear- cochlear for the auditory fibers and the vestibular complex for the balance/ equilibrium fibers

64

For CN VIII, involved

~both balance and auditory reflex
~cognitive awareness of movement, balance, and sound

65

CN IX: Glossopharyngeal Nerve

~enters brainstem laterally in rostral medulla
~Components: general sensory, special sensory, visceral sensory,

66

For CN IX, enters

brainstem laterally in rostral medulla

67

For CN IX, components

~General sensory: from pharynx, middle ear, & posterior 1/3 of tongue
~Special sensory: taste form he posterior 1/3 of tongue
~Visceral sensory: fibers from carotid bodies & carotid bodies
~ Branchial motor to stylopharyngeus muscle
~visceral motor- parasympathetic to parotid gland

68

CN X: Vagus Nerve

~enters brainstem laterally in rostral medulla
~components: general sensory, visceral sensory, special sensory, branchial (somatic) motor, autonomic efferents

69

For CN X, enters

brainstem laterally in rostral medulla

70

For CN X, Components

~general sensory: pharynx, larynx, trachea, cranial dura, & thoracic & abdominal viscera
~Visceral sensory: aortic baroreceptors
~special sensory of taste from epiglottis
~branchial (somatic) motor to pharyngeal & laryngeal muscles
~autonomic efferents to the thoracic & abdominal viscera

71

CN XI: Accessory

~two main parts: cranial and spinal
~function is somatic (branchial) motor

72

For CN XI, cranial

~arises from ventral lateral medulla

73

For CN XI, spinal

~rises from upper cervical spinal nerves
~ascends thru foramen magnum to join cranial portion

74

For CN XI, function

~is somatic (branchial) motor
~innervates: sternocleidomastoid and upper trapezius (cervical component) & pharyngeal and laryngeal (cranial component)

75

CN XII: Hypoglossal Nerve

~exits from ventral lateral medulla
~somatic motor- intrinsic and extrinsic tongue muscles

76

For CN XII, exits

from ventral lateral medulla

77

Reflexes

~most basic relationship between sensory input and motor output
~stereotyped motor response to a specific sensory stimulus
~involve afferent limb, integration within the CNS, & efferent (motor) limb

78

In brain stem reflexes, the afferent and efferent limbs may involve (same/different/both) cranial nerves

may involve same or different cranial nerves