U of U PA School Intro to Neuroanatomy

What are the parts of the neuron? (4)

Dendrites

Cell body + nucleus

Axon

Axon terminal

What are the parts of the axon?

Myelin sheath

Schwann cell

Node of Ranvier

Where do the body of neurons live?

In the CNS

What are the parts of the brain? (7)

Cerebrum

-Cortex (gray matter)

-Myelinated axons (white matter)

Brainstem

-Cranial nerves

Basal ganglia and thalamus

Cerebellum

What is included in the PNS? (5)

Spinal root

Plexus

Peripheral nerves

Neuromuscular junction

Motor nerve ending

How should a diagnosis be approached in neurology?

Characterize

-Sensory

-Motor

-Both

Localize

-What function is located where (CNS/PNS/both)

Differential

Diagnostic testing for differential

How do upper motor neurons and lower motor neurons differ?

Upper

-Cell body and axon reside in CNS

Lower

-Cell body in CNS

-Axon in PNS

What is somatotopic organization?

Correspondence of a specific point in the body to a specific point in the primary motor and sensory cortexes for controlling motor or sensory info

Organized into homunculus

Largest areas for face and hands

What is the internal capsule?

It consists of ascending and descending tracts (motor and sensory) that connect the thalamus and the cerebral cortex.

Why can smaller lesions that are deeper in the brain cause more issues?

Can interfere with internal capsule where tracts come together affecting more areas of the body

How does muscle movement occur?

Cortex -> brainstem -> spinal cord -> synapse at LMN nerve root -> plexus -> peripheral nerve -> NMJ -> muscle -> movement

How does sensory information travel to brain?

Sensory signal -> peripheral nerve -> plexus -> dorsal root ganglion at level of spinal root -> spinal cord -> brainstem -> thalamus -> cortex

What are the sensory tracts for sensory information? What is transmitted with each?

Spinothalamic tract

-Pain

-Temperature

Dorsal column

-Vibration

-Position sense

When does sensory information for each spinal tract cross to the opposite side?

Spinothalamic tract

-Crosses immediately in spinal cord

Dorsal column

-Medial lemniscal pathway - crosses in medulla

How is sensory/motor information processed in the brain?

Info from one side of body is processed in contralateral cortex

Most motor activity on one side of the body originates in contralateral cortex

Left hemisphere dominant for most people

What are the areas of the frontal lobe (4)? What do they do?

Primary motor cortex

Brocas area in left frontal lobe

-Produces language

Frontal eye fields

-Horizontal conjugate gaze

Prefrontal cortex

-Executive function

-Emotional regulation

What does a deficit in Brocas area cause?

Expressive aphasia

-Patient understands what is said but cant produce speech that is appropriate

What does a deficit in the prefrontal cortex cause? (4)

Loss of executive function

-Emotional instability

-Impulsivity

-Aggressive

-Change in social behavior, planning, and reasoning

What are the areas of the temporal lobe and what does it do?

Auditory cortex

Wernickes area in left temporal lobe

-Language comprehension

Hippocampus

-Memory

What does a deficit in Wernickes area cause?

Patients can speak but not understand

What are the language centers of the brain?

Brocas area

Wernickes area

Arcuate fasciculus

-Connects Brocas to Wernickes

What does a deficit in the arcuate fasciculus cause?

Cannot repeat what they have been told

What are the parts of the parietal lobe?

Primary sensory cortex

Sensory integration

Spatial coordinate system

What does right sided parietal lobe dysfunction cause?

Neglect

-Denial of the opposite side of space

-Constructional apraxia

--Inability to copy accurately drawings or three-dimensional constructions

What does left sided parietal lobe dysfunction cause?

Right-left disorientation

Acalculia - unable to calculate numbers

What does the occipital cortex do and what does dysfunction there cause?

Primary visual cortex

Lesions can cause homonymous hemianopsia

What does the cerebellum do and what does dysfunction there cause?

Balance and coordination

Mood/emotional regulation

Dysfunction

-Tremors

-Ataxia

What does the basal ganglia do and what does dysfunction there cause?

Regulates motor output

Dysfunction

-Hyperkinetic

-Hypokinetic

What does the thalamus do?

Relay all sensory pathways except olfactory and limbic

Regulate motor function

Maintain consciousness and alertness

What are the parts of the brainstem? What does it do?

Midbrain

Pons

Medulla

Motor fibers cross in medulla

-R brain controls L limb

What is the motor descending tract from brain to spine?

Corticospinal tract

What is a focal lesion?

Limited to a single location

-1 limb/1 part of limb

-1 area of the brain

What is a cortical deficit?

Deficit only in cortex

PNS has no cortical deficits

What are the cortical signs? (5)

Aphasia

Hemineglect

Personality changes

Memory loss

Gaze preference/deviation

Area involved tends to cause multiple symptoms