CSD 210 EXAM 2 REVIEW

Name the structure:

Midbrain

Name the structure:

Pons

Name the structure:

Medulla

Midbrain

• contains cerebral peduncles

• sleep/wake cycles

• alertness

• temperature rgulation

Pons

• contains cerebellar peduncles

• connects with cerebellum

Medulla

• vital functioning

  • breathing, heart rate, swallowing

Name this structure:

Caudal medulla

Name this structure:

Rostral medulla

Name this structure:

Caudal pons

Name this structure:

Rostral pons

Name this structure:

Caudal midbrain

Name this structure:

Rostral midbrain

Afferent

Ascending - SENSORY (body → brain)

Efferent

Descending - MOTOR (brain → body)

Midbrain CNs

CN III → CN IV

Pons CNs

CN V → CN VIII

Medulla CNs

CN IX → CN XII

CN I

Olfactory

• smell

• sensory

CN II

Optic

• visual

• sensory

CN III

CN IV

CN V

CN VI

CN VII

CN VIII

CN IX

CN X

CN XI

CN XII

Apex of cochlea

LOW frequency

Base of cochlea

HIGH frequency

Inner Hair Cells

Afferents (SENSORY)

• responsible for hearing

• SPECIFIC - each AN fiber receives signal from ONE IHC

Outer Hair Cells

Efferents

• responsible for helping to better align IHC to tectorial membrane

• amplify signal

• SENSITIVE - MANY OHC to one nerve fiber

• if ONE OHC goes off → nerve fires

auditory pathway

1. cochlear nucleus

2. superior olive

3. inferior colliculus

   1. ITD pathway

   2. ILD Pathway

4. medial geniculate body

cochlear nucleus

MONAURAL hearing

• receives information from IPSILATERAL cochlear nerve fibers

superior olive

BINAURAL hearing

• picks up BILATERAL cues

inferior colliculus

where sound localization occurs

ITD pathway (inferior colliculus)

sound localization at LOW frequencies where there is a TIMING difference

ILD pathway (inferior colliculus)

sound localization at HIGH frequencies where there is a LEVEL difference

medial geniculate body

located in the thalamus

anatomy of the eye

divided into:

• small anterior cavity

• large and round posterior cavity

anterior cavity of the eye contains:

• iris

• cornea

• lens

• aqueous humor - fluid similar to CSF

Where in the brainstem can you see the cerebral peduncles most prominently?

rostral midbrain

posterior cavity of the eye is the area between the _____.

lens & retina

what fills the posterior cavity of the eye?

vitreous fluid - jellylike substance

• maintains normal intraocular pressure

• prevents eyeball from collapsing

outer ear

pinna - funnels sound into ear canal

middle ear

amplifies sound by changing it from large → small diameter

• ossicles - change diameter of sound vibration

inner ear

cochlea - translates sound from mechanical energy into electrical information

fluid in scala vestibuli

perilymph

fluid in scala media

endolymph

fluid in scala tympani

perilymph

where is the organ of corti located

scala media

organ of corti

primarily responsible for sound transduction

where are hair cells located?

on the basilar membrane

filaments on top of hair cells

stereocilia - get deformed by sound waves

• all connected

• Ca 2+ and K+ enter hair cell → action potential

cellular transduction

• photos move POSTERIORLY (towards back of eye)

• signal moves ANTERIORLY (towards front of eye)

rods

• night/low light vision

• mostly in PERIPHERY

cones

• color & acuity (most accurate/crisp vision)

• mostly concentrated in fovea

streams of association processing:

• dorsal stream

• ventral stream

dorsal stream

motion processing

• “where”

• projects to PARIETAL lobe

ventral stream

objective recognition

• “what”

• projects to TEMPORAL lobe

limbic system

learning, emotions, & homeostasis

the limbic system contains:

• thalamus

• hypothalamus

• amygdala

• hippocampus

• fornix

thalamus

sensory relay station

• medial geniculate body

• lateral geniculate body

hypothalamus

homeostasis, hunger, thirst, vital functioning

amygdala

emotions (fear pleasure, reward); how one sees themselves

hippocampus

learning & memory

fornix

“C” shape that connects many structures

where in the auditory pathway is hearing binaural?

• superior olive

• inferior colliculus

• thalamus - medial geniculate body

reward/punishment functions of limbic system:

help us “learn'“ and motivates behavior (or lack of behavior)

• impaired by drugs and psychiatric disorders

reward centers:

• hypothalamus

• septum

• amygdala

• thalamus

• basal ganglia

punishment centers:

• periaqueductal grey

• hypothalamus

• thalamus

what can take precedence over pleasure & reward?

punishment & fear

sensorimotor

a task is NEVER purely motor

• always getting sensory feedback and correcting

anatomy of spinal cord:

• DORSAL - afferent (SENSORY in)

• VENTRAL - efferent (MOTOR out)

sensory fiber tracts

1. dorsal column pathway

2. spinothalamic tract

dorsal column pathway

touch, proprioception, vibration

optic chaism

point where PARTIAL crossing of optic nerves occurs

optic tract

AFTER crossing; white mater tract

optic radiations

AFTER crossing & thalamus; white matter tract

• send signals to primary visual cortex

spinothalamic tract

slower, unmyelinated, pain, & temperature

important MOTOR spinal tracts

• corticospinal tract

• corticobulbar tract

corticospinal tract

• fibers originated from cortex & descend to spinal cord

• cross midline in the pyramids of medulla (brainstem)

• control CONTRALATERAL muscles throughout the entire body

corticobulbar tract

• fibers originated from cerebral cortex & descend…

  • through the internal capsule

  • in the midbrain through cerebral peduncle

• cross midline in brainstem at level of the CN nuclei they innervate

• BILATERAL projections

visual system pathway:

1. retina

2. optic nerve

3. optic chiasm

4. optic tracy

5. lateral geniculate body

6. optic radiation

7. primary visual cortex (V1)

Damage to the left optic tract would cause:

loss of vision in the right visual field

Upper motor neurons

• located in CNS

  • within motor cortex of brain & certain brainstem nuclei'

• responsible for conveying motor signal from the brain to the LMNs in the spinal cord or brainstem

  • play crucial role in the initiation, planning, & modulation of VOLUNTARY movements

Lower motor neurons

• located in PNS

  • within anterior horn of spinal cord & certain brainstem nuclei

• innervate skeletal muscles

  • transmit motor commands initiated by UMNs

• responsible for the execution of VOLUNTARY muscle movemtns

• * releases ACh *

types of movement:

1. reflex

2. central pathway

3. volitional

pyramidal (DIRECT) pathway

• corticospinal tract

• corticobulbar tract

• originated from primary motor cortex

extrapyramidal (INDIRECT) pathway

• tectospinal tract

• rubrospinal tract

• vestibulospinal tract

• involved with the basal gangli and cerebellum

  • takes LONGER

basal ganglia

• striatum - major INPUT (from motor cortex)

• globus pallidus - major OUTPUT (thalamus)

• substantia nigra - major OUTPUT (brainstem)

  CONTRALATERAL deficits in body if there is damage to basal ganglia

damage to basal ganglia causes:

• parkinson’s disease

• huntington’s disease

parkinson’s disease

• HYPOkinesia - lack of movement

• depleted dopamine (substantia nigra)

• rigidity

• resting tremor

huntington’s disease

• HYPERkinesia - excessive movement

• uncontrolled movements

• cognitive & psychological deficits

cerebellum

• input:

  • sensory systems (throughout body)

  • sensorimotor systems (cortex & basal ganglia)

• output:

  • brainstem, extrapyramidal system, thalamus → cerebral motor cortices

• damage causes:

  • ataxia - poorly coordinated movements

  • posture/gait problems

• IPSILATERAL effects on body

What is the primary nucleus in the basal ganglia with inputs from the cortex?

striatum

What kind of deficits are caused by damage to the basal ganglia?

contralateral

What kind of deficits are caused by damage to the cerebellum?

ipsilateral

A patient has increased muscle tone, spasticity, & exaggerated reflexes. Where do you expect there to be damage?

Upper motor neuron