Neurology Flashcards
What is Neurology?
Branch of medicine that deals with the anatomy, physiology (function), and disorders of the nervous system
Cell Anatomy:
Name parts of a cell
- Dendrites
- Cell body/Soma
- Axon
- Nodes of Ranvier
- Terminal button
Dendrites
receptor branches on cell body
Cell body/Soma
- contains DNA
- * “Ganglia” - clusters of cell bodies in PNS
- * “Nuclei” clusters of cell bodies in CNS
Axon
- Transmits electrical impulses from cell body to terminal buttons
- covered in a myelin sheath
- “Tract” = bundle of axons in CNS
- “Nerve” = bundle of axons in the PNS
Nodes of Ranvier
gaps in myelination on axon
Terminal button
contains synaptic vesicles
Ganglia
clusters of cell bodies in PNS
Nuclei
clusters of cell bodies in CNS
Tract
bundle of axons in the CNS
Nerve
bundle of axons in PNS
2 main types of cells
- Glial cells
- Neurons
Function of Glial cells
supports cell function
Function of Neurons
Communication
Types of Neurons
- Sensory neurons (receptors)
- Interneurons
- Motor neurons (effectors)
Function and types of
Sensory Neurons (receptors)
- Function: transmits sensory info into nervous system
- Examples:
- Chemoreceptors: chemicals
- Thermoreceptors: temperature
- Mechanoreceptors: force/pressure
- Photoreceptors: light during vision
- Baroreceptors: changes in blood pressure
- Proprioceptors: position
Function of Interneurons
makes connections between sensory and motor neurons
Function of
Motor Neurons (effectors)
- receives excitation from other cells and sends impulses (signal transmission)
- instructs muscles to contract or glands to secrete
Explain cellular communication
Information is transmitted into the nervous system by the conversion of electrical energy into chemical energy and then back into electrical energy.
- Electrical energy moves within the neuron from the body to the axon
- The electrical signal is converted to a chemical signal at the synaptic cleft between cells.
- Neurotransmitters are biomechanical compounds that help neurons communicate, acting as messengers between them.
- Neurotransmitters move from one cell to the receptor site on the post synaptic membrane, resulting in a change in electrical current across the cell membrane
- The change in electrical value is known as an action potential
Divisions of the Nervous System and their components
- Central Nervous System (CNS)
- includes brain & spinal cord
- Peripheral Nervous System (PNS): Nerves & ganglia (cell bodies outside of CNS
- includes :
- Somatic Nervous System
- Autonomic Nervous system
- includes :
Name meninges
of the brain
- Meninges (outer coverings)
- Dura Mater
- Arachnoid Membrane
- Pia Mater
- Between arachnoid & pia mater is the subarachnoid space which contains blood vessels and cerebrospinal fluid (CSF)
Cerebrospinal Fluid (CSF)
Function
cleans and protects the brain and spinal cord by
circulating throughout the ventricles
Name the Ventricles
in the brain
- Two lateral ventricles
- Third ventricle
- Fourth Ventricle
4 Main Components
of the Brain
- Cerebrum (lobes)
- Cerebellum
- Subcortical structures
- Brainstem
Cerebrum
components
- Gray matter - densely packed cell bodies in the cortex which give the gray appearance.
- other regions of gray matter: Thalamus, spinal cord, etc.
- White matter - axons that are wrapped in myelin, giving a whitish appearance
- Two Hemispheres (right and left)
- Lobes:
- Frontal
- Temporal
- Parietal
- Occipital
- Insula (underneath)
- Lobes:
Cerebrum:
Lateralization
When a function is primarily controlled by one hemisphere versus the other.
- speech and language are thought to be controlled by the left hemisphere in about 95% of people
Cerebrum:
Specialization
When certain brain regions serve distinct functions
- ex. Frontal lobe is specialized for executive function
Frontal Lobe Main Functions
Main functions:
- control for movement
- planning
- initiation
- judgement
- reasoning
- concentration
- disinhibition of behaviors
- adaption to change
- emotional response
Parts of
Frontal Lobe
- Primary Motor Cortex
- contains motor neurons that send signals to execute movement
- motor neurons are arranged in a somatotopic fashion
- disproportionate number of neurons devoted to control of structures which SLPs are most concerned
- Premotor Cortex (including Supplementary motor area)
- Plans movement
- Also includes Broca’s area (left frontal lobe) - significant representation for speech
- Prefrontal Cortex
- Executive function (attention, inhibition, flexibility, working memory, problem solving, etc.)
Primary Motor Cortex
location & function
Location: Frontal lobe
Function: contains motor neurons that send signals to execute movement
- arranged in somatotopic fashion (specific part of body is associated with distinct location)
- disproportionate number of neurons devoted to control of structures with which SLPs are most concerned
Premotor Cortex
Location & Function
Location: Frontal Lobe includes supplementary motor area
Function: Plans movement
- includes Broca’s area (left frontal lobe)
- significant representation for speech
Prefrontal Cortex
Location & Function
Location: Frontal Lobe
Function: Executive function (attention, inhibition, flexibility, working memory, problem solving, etc.)
Temporal Lobe Main Functions
Main functions:
- Hearing ability
- Memory acquisition
- Visual Perceptions
- Categoriztion of objects
Temporal Lobe Components
- Primary & secondary auditory cortices
- Function: Auditory sensation & perception
- Wernicke’s area (left lobe)
- Auditory comprehension of language
Primary and Secondary
Auditory Cortices
location & function
Location: Temporal Lobe
Function: Auditory sensation and perception
Wernicke’s Area
location & function
Location: Temporal Lobe (Left lobe)
Function: Auditory comprehension of language
Parietal Lobe Main Functions
Main functions:
- receives and evaluates most sensory information
- touch, pressure, pain, temperature & taste
Parietal Lobe Components
- Primary Somatosensory Cortex
- Posterior Parietal Complex
Primary Somatosensory Cortex Location & Function
Location: Parietal Lobe
Functions:
- responds to touch/pain stimuli from body
- sensory neurons are arranged in a somatotopic fashion
Posterior Parietal Complex
Location & Function
Location: Parietal Lobe
Function:
- integrates sensory stimuli to create complex experiences
- “association” cortex - associates different types of sensory stimuli to direct action plans based on that info.
- Ex. Object recognition in the hand
- Damage = agnosia, inability to recognize objects
- Areas involved in high-level langauge
- Angular gyrus = higher-order language such as math
- Supramarginal gyrus = word meanings with action patterns (i.e. whistling).
What areas are involved in high-level language?
Angular gyrus
- higher order language such as math
Supramarginal gyrus
- word meanings with action patterns (i.e. “whistling”)
- Both located in Parietal lobe - Posterier Parietal Complex*
Occipital Lobe Main Functions
Main functions:
- visual processing
- help with visual associations
Insula Functions
- sometimes referred to as the “5th lobe”
- Functions:
- not fully described in the literature yet
- sensory & motor, related to speech and language
Cerebellum Functions & Components
- Parts -
- Two hemispheres & 3 lobes
- Main functions:
- Receives movement info from cortex
- Analyzes body movement & compares it to what is needed to accomplish task, then coordinates correction of movements (if needed)
- balance
- Executing coordinated movements
Subcortical Structures Main Functions & Parts
Main Functions & Parts:
- Thalamus - Processes sensory information, then relays it to the cerebral cortex
-
Hypothalamus - regulates endocrine functions (hormones)
- has connections to the thalamus, reticular fomation, cerebral cortex, limbic system, olfactory bulb, & midbrain
- Pituitary gland - “master gland”; controlling secretions from thyroid, adrenal gland, ovaries & testes
- Hippocampus - recent working memory, inhibiting an unsuccessful action
- Amygdala - forming and storing memories associated with emotional events
- Basal ganglia - receives info from cortex, processes it, and sends back to cortex via Thalamus of motor control
Brainstem Function & Components
Function:
- connects brain to spinal cord
Main Components:
- Midbrain
- Pons
- Medulla
Midbrain Location & Function
Location: Brainstem
Function:
- superior colliculus: vision
- Inferior colliculus: hearing
- Nuclei for oculomotor & trochlear cranial nerves; eye movement & sensation
- Substantia nigra: produces neurotransmitter dopamine; reward center
Pons Location & Function
Location: Brain stem
Functions:
- Nuclei for trigeminal, abducens, facial & vestibulocochlear cranial nerves
- Bridge for cerebellum
- Part of reticular activating formation; helps control breathing and sleep (alertness & arousal)
Medulla Location, Functions & Parts
Location: Brainstem
Functions:
- Part of Reticular activating formation: overall arousal and sleep
Parts:
- Ascending & Descending tracts
- Nuclei for glossopharyngeal, vagus, accessory, hypoglossal cranial nerves
Sections of
Spinal Cord
- Cervical - 8 Cervical nerves
- Thoracic - 12 Thoracic Nerves
- Lumbar - 5 Lumbar Nerves
- Sacral - 5 Sacral Nerves
- Coccygeal - 1 nerve
Spinal Cord Components & Functions
- Meninges - protective layers
- Ventral & Dorsal roots
- Dorsal - sensory info
- Ventral - motor info
- Doral root ganglia (collection of cell bodies)
- Gray and white matter
- Variation of details throughout the spinal cord, but not essential features
Peripheral Nervous System (PNS) Divisions & Functions
Function:
- connects CNS to the rest of the body
- made up of motor (efferent) & sensory (afferent) nerves
Divisions & their Functions:
- Somatic Nervous System
- voluntary control (e.g. control of muscle movement)
- Autonomic Nervous System
- involuntary control (e.g. heart rate, digestion)
Efferent Nerves
Motor (efferent) nerves: from CNS to body
Afferent Nerves
Sensory (afferent) nerves: sensory receptors in body to CNS
Nervous System Communication
Communication between one area of the nervous system to another happens via:
- Tracts: collection of axons in CNS
- Nerves collection of axons in PNS
Tracts
collection of axons in the CNS
Nerves
collection of axons in the PNS
CNS Tracts
- Association
- Sriatal
- Commissural
- Descending projection tracts
- Corticobulbar
- Corticospinal
- Corticothalamic
- Ascending projection tracts
- Posterior column/medial lemniscus
- Anterolateral
- Thalamocortical
CNS TRACT:
Association Tracts
Intrahemispheric, both within and between lobes
CNS TRACTS:
STRIATAL TRACTS
From cortex to basal ganglia (principally to caudate and putamen) and from cortex to subthalamic nucleus
CNS TRACTS:
Commissural Tracts
Interhemispheric, from specific area of one hemisphere to similar area of the other hemisphere
CNS TRACTS:
Descending Projection Tracts
- Corticobulbar - motor cortex to cell groups in brain stem
- Corticospinal - Motor cortex to cell groups in spinal cord
- Corticothalamic - Widespread regions of the cortex to cell groups in the thalamus
CNS TRACTS:
Ascending Projection Tracts
- Posterior column/medial lemniscus - spinal cord to brainstem nuclei and thalamus
- Anterolateral - Spinal cord to thalamus
- Thalamocortical - cell groups in the thalamus to widespread regions of the cortex
PNS Nerves
-
Cranial nerves (except optic)
- remember: their nuclei (cell bodies) are in the CNS
- 10 cranial nerves originate in brainstem
- 2 originate in the cerebrum (olfactory & optic)
-
Spinal nerves (and their roots & branches)
- 31 paired spinal nerves
Cerebral Blood Flow Components
Two arterial systems :
- Carotid Arteries (anterior circulation)
- Internal carotid arteries ( Left & right branches)
- Anterior Cerebral Artery (ACA)
- Middle Cerebral Artery (MCA)
- Posterior Cerebral Artery (PCA)
- External carotid arteries (Left & Right branches)
- Internal carotid arteries ( Left & right branches)
- Vertebral Arteries (posterior circulation)
CEREBRAL BLOOD FLOW:
CIRCLE OF WILLIS
