Nervous System: Brain and Spinal Cord Flashcards
Where is the ‘Cerebral Cortex’ and what is it made from?
The outer rim of the cerebrum.
Contains billions of layers of neurons
Grey matter
Cerebral cortex during embryonic development
Grows faster than white matter.
Results in folding in the cortical region
What are the left and right hemisphere split by?
Longitudle fissure
What is cerebral white matter made from?
Primarily myelinated axons
Name the three types of tracts of cerebral white matter:
Association: Nerve impulses through axons to and from gyri in the same hemisphere
Commiseral: Conduct between gyri in different hemispheres
projection: Cerebrum to CNS or low parts of CNS to the cerebrum
Where is the primary visual cortex located?
The back end of the occipital lobe
Where is the primary somatosensory cortex located?
The parietal area
The lateral fissure primarily separates the:
Frontal from temporal lobe
The key function of the temporal association cortex:
- Memory
- Aggression
- Mood
The key function of the frontal association cortex:
- Intelligence
- Personality
- Behaviour
The key function of the parietal association cortex:
- Spacial skills
- 3D recognition
The function of arcuate fasciculus
- To align speech recognition/comprehension with speech production
- Goes from Wernicke’s area to Broca’s area
- Lesion causes connectional aphasia
Major symptoms of a person with non-fluent aphasia
- Inability to coordinate muscular movements for generating speech
- Can understand but can’t speak
- Lesion in Broca’s area
Fluent aphasia
- Caused by a lesion in Wernicke’s area
- Person can speak but not coherently
Connectional aphasia
- Legion in arcuate fascicula
- Makes people say stuff that isn’t relevant to the conversation
Broca’s speech area
- Speaking and understanding language
- From this area, nerve impulses pass through premotor regions which control muscles of the larynx, pharynx, and mouth
- Legion = can’t speak thoughts (non-fluent aphasia)
Cerebellum function
- Smooths and coordinates skeletal muscle contractions
- Regulates posture and balance
Parts of diencephalon
- Thalamus
- Hypotherlumus
- Epithalamus
Thalamus function
- Relays almost all sensory information to the cerebral cortex
- Maintenance of consciousness
- Contributes to motor function
Hypothalamus
- Autonomic nervous system
- Produces, releases, and inhibits hormones like oxytocin and ADH
- Emotional and behavioral patterns
- Regulates satiety, thirst, and temperature
Epithalamus
- Consists of the pineal gland
- Secretes melatonin
- Habenular nuclei (involved in olfaction)
Basal nuclei: primary function
1) Receives information from the cerebral cortex
2) Provides output to motor parts of cortex via the medial and ventral group nuclei of the thalamus
Basal nuclei: other functions
- Initiation and termination of movement
- Control subconscious contraction of skeletal muscles
- Made of grey matter
- Lesions can cause Parkinson’s, OCD, schizophrenia, Huntington’s, turrets, etc.
The three parts of the brainstem, top to bottom:
Midbrain, pons, medulla oblongata
Midbrain
- Contains sensory (ascending) and motor (descending) tracts
- Superior colliculi coordinate movements of the head, eyes, and trunk in response to visual stimuli
- Inferior colliculi do the same but in response to auditory stimulu
Superior colliculi
Visual
Inferior colliculi
Auditory
Pons
- Contains sensory (ascending) and motor (descending) tracts
- Pontine nuclei relay nerve impulses from motor areas of the cerebral cortex to the cerebellum
- Along with medulla, contains vesicular nuclei that are part of equilibrium pathway to the brain
Medulla Oblongata
- Contains sensory (ascending) and motor (descending) tracts
Cerebrum
- Involved in the perception of information
- Basal nuclei: initiate and terminate movement, regulate muscle tone
- Limbic system: promotes a range of emotions, including pleasure, pain, docility, affection, anger, etc.
Anatomy of spinal cord
- 31 pairs of spinal nerves
- Dorsal (sensory) and ventral motor roots
- Grey and white matter
Meninges
- The protective connective tissue coverings encircle the spinal cord
- From inside out, pia mater, arachnoid mater, dura mater
Spinal cord: motor output
- Ventral root fibers
- Lower motor neurons
peripheral nerve - motor endplate/muscles
Spinal cord: sensory input
- Peripheral receptors/dermatomes
- Discriminative touch and pressure
- Non-discriminative pain and temperature
- Dorsal root fibers/ganglia/central connections
Non-discriminative pathways
- Pain and temperature
- Free nerve ending
- Not fired as often
- Slow, about 1m/s
- Unmyelinated
Discriminative pathway
- Tough and pressure
- Encapsulated receptor
- Pressure = Pacinian corpsule
- Touch = meisners corpuscle
- Myelinated
Discriminative: Neuron 1
Start: Primary root afferent
Middle: Dorsal column of the spinal cord
End: Gracile or cuneate nucleus
Discriminative: Neuron 2
Start: Gracile or cuneate nucleus
Middle: Internal arcuate fibers/medial lemniscus
End: ventro-posterior thalamus
Discriminative: Neuron 3
Start: Ventro-posterior thalamus
Middle: Internal capsule
End: Primary somatosensory cortex
Non-Discriminative: Neuron 1
Start: Primary root afferents
Middle: Dorsal root ganglion
End: Dorsal horn of the spinal cord
Non-Discriminative: Neuron 2
Start: Dorsal horn of the spinal cord
Middle: lateral spinothalamic tract
End: Ventro-posterior thalamus
Non-Discriminative: Neuron 3
Start: Ventro-posterior thalamus
Middle: Internal capsule
End: Primary somatosensory cortex
The pathway to the brainstem which conveys discriminative touch and pressure sensation is the:
Medial lemniscus
The pathway in the brainstem for non-discriminatory pain and temperature is the:
Lateral spinothalamic tract
Both Non-Discriminative and Discriminative pathways terminate in the:
The ventro-posterior nucleus of the thalamus
Motor symptoms of lesion on right side of basal ganglia
- Effects left side of the body
- Unrefined voluntary movements
- Difficulty initiating movement
- Difficulty with handwriting and expressing mood due to loss of smoothing system
Motor symptoms of lesions on the right side of the cerebellum
- Loss of balance
- Right side of the body
- Difficulty stopping movement
- Loss of normalization of actual movement to align with the planned movement
Lesion on right side of arm area in the motor cortex
- Left side of the body
- Loss of voluntary contraction of the limb
- Spastic paralysis
Lesion on right side of lower motor neurons of spinal cord
- Right side of the body
- Flaccid paralysis
- Muscles are unable to be controlled either voluntarily or involuntary
A patient has a sudden stroke. Their symptoms include:
- Spastic paralysis on the left side of the face and upper left limb
- Loss of hearing in the left ear
- Problems with non-verbal communication
What areas did the stroke affect?
- Right primary motor cortex
- Right auditory complex
- Right somatosensory cortex
- Non-dominant hemisphere (right)
Most characteristic symptoms of Parkinson’s disease
- Bradykinesia
- Rigidity
- Tremor at rest
The most recently developed surgical treatment of P.D is __________ of the region in the basal ganglia known as the ________.
- Deep brain stimulation
- Subthalamic nucleus/globus pallidus internal
The cerebral hemispheres are connected internally by the:
Corpus callosum
The cell bodies of upper motor neurons are located in the:
Motor cortex
The lateral spinothalamic tract conveys:
Sensory impulses regarding pain and temperature
Treatment for Parkinson’s disease
- Lesion in the thalamus
- Deep brain stimulation
- A lesion in the globus pallidus
- Drug treatment with L-DOPA
Receptors for the pressure that are widely distributed in the subcutaneous tissue and submucosal tissue are the:
Pacinian corpuscles
The primary visual area and the visual association area of the cerebral cortex are both located in the:
Occipital lobe
The posterior (dorsal) root ganglion is:
Where the cell bodies of sensory neurons are located
The medial lemniscus is a projection tract of second-order neurons extending from the:
Medulla to the thalamus
Symptoms from a lesion of the corticospinal tract on the right side of the brainstem:
A spastic paralysis on the left side of the body
Cell bodies of motor neurons to skeletal muscle are located in the:
Anterior grey horn
If a stroke caused damage to the posterior third of the inferior frontal gyrus in the left hemisphere, what would the expected result be?
Motor/expressive aphasia
Lamina terminalis:
- In brain
- Thin sheet of grey and pia mater
- Essential in Na+ secretion
- Between hypothalamus and forebrain
Septum pellucidum:
- Below corpus callosum
- Partition between a potion of lateral ventricles
- Made of white matter, neurons, fiber bundles, and blood vessels
Interventricular foramen
- Near hypothalamus and fornix
- Connects lateral ventricles to the third ventricle
- Transport of cerebral spinal fluid through the brain
Fornix
- Above hypothalamus
- Transmits information from the hippocampus to the mammillary bodies and anterior nucleus of the thalamus
These habits and emotions are controlled primarily by the hypothalamus
- Eating and drinking
- Rage and aggression
- Body temperature
- Pain and pleasure
Cerebrospinal fluid is formed by this structure
Choroid plexus
The internal capsule is composed of which fiber tracts
projection tracts
Which part of the limbic system functions with other parts of the cerebrum in memory
hippocampus
The cerebral lobe that is deep within the lateral cerebral sulcus and not evident in the external view of the brain
insula
Paired masses of gray matter within the white matter of the cerebrum that are rich in dopamine and are involved in the maintenance of muscle tone are called
basal ganglia
This structure produces a variety of hormones and monitors the water concentration and temperature of the blood
hypothalamus
The left side of the cerebrum controls skeletal muscles on the right side of the body because motor neurons cross from left to right where:
medulla
In the thalamus, hypothalamus and pineal gland develop from what structure
Diencephalon
The primary motor area of the cerebral cortex is located where
precentral gyrus
the structure that connects the pituitary gland to the hypothalamus
infundibulum
These abilities are controlled by the right cerebral hemisphere
space and pattern perception
imagination
artistic awareness
muscles on the left side of the body
Which cranial nerve contains large motor and sensory components
Vagus
The gray matter of the central nervous system consists of these structures
Cell bodies and dendrites
The cerebral aqueduct connects what structures
third and fourth ventricles
The region of the brain that borders each side of the third ventricle
thalamus
Physiological functions regulated by the medulla
Heart rate
respiratory rate
blood vessel diameter
swallowing
Pain, pleasure, rage, fear, sorrow, sexual feelings, docility, and affection are primarily functions of which brain area
the limbic system
4 major parts of the brain
brain stem
diencephalon
cerebrum
cerebellum
CSF is produced in this area because it is lined with these cells
choroid plexus
ependymal cells
The largest cavity located in each hemisphere of the cerebrum is
lateral ventricle
The brain area that translates thoughts into speech
Broca’s area
The brain area that understands words
Wernicke’s area
The brain structure controls 2 main vital systems and what are they
Medulla: cardiovascular center and respiratory system
This area of the cerebrum receives sensations related to taste
primary gustatory area
Structures of the diencephalon
thalamus
epithalamus
hypothalamus
The CSF formed in the choroid plexuses and circulates continually through which areas of the brain
subarachnoid spaces
ventricles
central canal
Function of CSF
shock absorber
nutrition
waste removal
The blood-brain barrier is formed from which cells
astrocytes
Brain’s islands of white matter are comprised of what structures
axons
Brain’s islands of grey matter are comprised of what structures
nuclei
left brain function
sensation from the right side of the body
controls muscles of the right side of the body
reasoning
math science
language - spoken, written, sign
dominant in right-handed individuals
right brain function
sensation from the left side of the body controls muscles on the left side of the body patterns music art recognition of the face, emotion the emotional content of language dominant in left-handed individuals
Projection tracts are located where
internal capsule
the major relay station of the brain for both sensory-motor impulses and autonomic activity
thalamus
meaning of the term “limbic”
borderline; located at the border of the cerebrum to the border of the diencephalon
2 components of the limbic system
amygdala - rage and aggression
hippocampus - memory
Axons that connect the lower parts of the brain to the cerebrum
Projection tracts
The thalamus borders this ventricle
3rd
Epithalamus is made of 2 structures
the pineal glands habenular nuclei (regulates emotional responses to odors)
This gland produces melatonin which promotes sleep
pineal gland
Hypothalamus tells this gland what to do
pituitary