Organization of CNS (Glendinning) Flashcards Preview

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Flashcards in Organization of CNS (Glendinning) Deck (14):

1. Describe the basic divisions of the CNS. Identify the cortex, brainstem, thalamus, and spinal cord.

Spinal Cord:
- Extends from foramen magnum to L1
- Cervical (C1-C8)
- Thoracic (T1-T12)
- Lumbar (L1-L5)
- Sacral (S1-S5)
- Coccygeal (Co1)


3 major features of the spinal cord

Identify the sensory and motor regions of the spinal cord.

Spinal cord circuits

3 major features:
1. Long and short pathways
2. Spinal nerves
3. Grey matter

Dorsal root - sensory input/afferents
Ventral root - motor output/efferents

Spinal cord circuits:
- Reflex circuits - feedback inhibition or negative feedback (i.e. stretch reflex)
- Basic motor circuits - postural and locomotor outputs
- Sensory processing


2 major features of brainstem

Identify the 3 major areas of the brainstem.

2 major features: exiting (entering) cranial nerves and long pathways

Medulla oblongata


Explain the general function and list the cranial nerves associated with each region of the brainstem.

Ventral surface of brainstem:
- Most of the cranial nerves exit the ventral surface
- Corticospinal tract (major descending pathway)

IX, X, XI, XII (cardiac, pulmonary) - receives info from:
- Taste structures
- Skin of head, heart, and lungs
- Major blood vessels
- Digestive system

Several nuclei (grey matter):
- Regulates body homeostasis: HR, Respiration, vasomotor tone, gastric secretions
- Related reflexes: vomiting, coughing, sneezing, swallowing, gagging

If medulla is compressed (herniations through foramen magnum) -> fatal outcome

PONS (big bridge to cerebellum):
V, VI, VII, VIII (5-8)
Several nuclei:
- Balance
- Localizing sound
- Coordinating eye movements
- Facial expression

Related reflexes: eye movements, jaw jerks

Large pathway into the cerebellum

MIDBRAIN (mesencephalon)
III, IV (involved with extra ocular control)
Several nuclei:
- Control orienting to sound, visual reflexes, motor control

Projections to the cortex:
- Substantia nigra, ventral tegmental area source of dopamine projections to cortical areas (movement and "reward")

Habit formation pathways originate in midbrain


Define the reticular formation and describe its location in the brainstem.

Nuclei and neuronal circuits
- have net-like appearance
- run through core of brainstem
- many nuclei are the origin of projections to the cortex or spinal cord

Example: Caudal reticular formation includes centers that control:
- Respiratory rhythms
- BP
- Digestion
- Reflexes: facial expressions, gag, yawn, swallowing, vomiting
*All medulla

The more rostral portion modulates forebrain activity


Explain the significance of the "reticular activating system."

Rostral projections from PONS and MIDBRAIN (pontomesencephalic)

Project directly to cortex or through thalamus to control ATTENTION, AROUSAL, SLEEP, WAKEFULNESS

Includes several neurotransmitters systems

if affected, ppl will end up in coma


Identify the thalamus and describe its general function.

What makes up the diencephalon?

Projections to the cortex = THALAMOCORTICAL RADIATIONS

Major relay station for all inputs to the cortex
examples: sensory (except olfactory), motor (e.g., cerebellum), reticular formation, limbic system

Thalamus, hypothalamus, epithalamus, sub thalamus = DIENCEPHALON


Identify the two major structures that comprise the cerebral hemispheres.

CORTEX and BASAL GANGLIA (collection of gray matter in the cerebrum - chooses and initiates motor patterns and behaviors - generates habits)


List and describe the function of each of the 6 layers of the cortex (outer surface: grey matter)

I: Molecular: synaptic contacts from other layers

II: Small pyramidal: corticocortical (PREFRONTAL ASSOCIATION CORTEX)

III: Medium pyramidal: corticocortical (PREFRONTAL ASSOCIATION CORTEX)

IV: Granular: SENSORY inputs from thalamus

V: Large pyramidal: MOTOR outputs to CNS

VI: Polymorphic: outputs to thalamus


Identify the 5 lobes of the cortex and explain the general functions located within each lobe.

Frontal: planning, organizing, controlling behavior

Parietal: sensory perception of self and world

Occipital: visual processing

Temporal: Auditory (superior), visual (middle), and memory (medial) processing

Limbic: emotional processing and memory consolidation


Explain the concept of somatotopy, retinotopy, tonotopy in primary cortices.

Primary cortices are topographically organized - sensory "fields" are represented in orderly manner within primary cortex

Somatotopy - arrangement of primary somatosensory and motor cortices
Retinotopy - arrangement in primary visual cortex
Tonotopy - arrangement in primary auditory cortex

These representations are examples of LOCALIZATION of function


Locate the regions of the cortex occupied by the limbic system.

Includes medial regions of cortex, with hippocampal formation and amygdala

Involved in processing of Long-Term memory and emotional memory --> Allocortex - 3 layers


Identify the cerebellum and describe its general function:

motor control and learning, posture, orientation, balance

3-layered cortex

enables FEEDFORWARD control (anticipate movement)

Damage to cerebellum causes ATAXIA (disordered movement)


Where is the ASSOCIATION CORTEX located and what does it do?

Located in primary auditory cortex (in Sylvian fissure)

Carries out higher-order processing (e.g., perceptions, judgments, organization, calculations, language)