What does the dorsal solumn-medial lemniscus control?
Show answer
• vibration
• consious priopioception
• fine touch
12
What does the spinothalamic tract control?
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• crude touch
• pressure
• pain
• temperature
13
What does the spinocerebellar tract control?
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position of body parts
14
What are the descending spinal tracts and what do they control?
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Direct - voluntary and fine movement
• pyramidal
• corticospinal
• corticobulbar
Indirect - balance, posture, muscles tone, coordination
• extrapyramidal tract
15
What is a reflex arc?
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Involuntary rapid reflex mediated by the spinal cord before stimulating the brain
16
What are the components of a reflex arc?
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Receptor + sensory neuron with 1+ synapses to generate quick efferent output
(via motor neuron + muscle)
17
What are the functions of the cervical region of the spinal cord?
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Controls sensation/movement of the neck and upper body, and autonomic functions like breathing and heart rate.
18
Consequences of a transection at C1-C3 ?
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No function below the head and a ventilator is needed.
19
Transection at C4-C5 vs C6-C8?
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C4-C5 = quadriplegia
C6-C8 = loss of lower limb function but some upper limb may be intact
20
Transection at T1-9
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Paraplegia
paralysis in lower body and legs but upper limb intact
21
Transection at T10-L3
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some dysfunction in lower limbs
22
What are the three layers of the meninges?
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Pia mater, arachnoid, and dura mater
23
What is cerebrospinal fluid (CSF)?
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CSF is a clear, colorless, and sterile ultrafiltrate of blood.
24
What is the function of arachnoid villi?
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one-way valves between the subarachnoid space and the venous system
25
What are the main components of cerebrospinal fluid (CSF)?
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Water, ions, glucose, small amounts of proteins, and small number of lymphocytes.
26
What are the functions of cerebrospinal fluid (CSF)?
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a) hydromechanical protection
b) Providing nutrients, removing waste
c) Neuromodulators transport
27
What is the choroid plexus?
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A highly vascular tissue that projects into the ventricles and is lined by ependymal cells.
28
What is the main function of the choroid plexus?
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To remove water and solutes from the blood and release it as cerebrospinal fluid (CSF).
29
What is the dura mater and what are its layers?
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Outermost layer of the brain meninges
formed by the periosteal layer + inner meningeal layer
30
What is the subdural space and what does it contain?
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The subdural space is a narrow space between the dura mater and the arachnoid. It contains a scarce amount of cerebrospinal fluid (CSF).
31
What is the arachnoid mater?
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layer that covers the subarachnoid space
surrounds the brain and spinal cord
32
What is the subarachnoid space?
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between the arachnoid and pia mater
contains CSF, blood vessels, and cranial nerves
33
What space does the CSF use for circulation
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subarachnoid space
34
What is the function of the arachnoid villi?
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They act as a conduit for CSF to return to the venous circulation.
35
What is the pia mater?
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innermost layer
connective tissue that covers the brain surface
36
What are the leptomeninges?
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The arachnoid mater and pia mater.
37
What is meningitis?
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An inflammatory condition that typically affects the leptomeninges.
38
What are the components of the blood brain barrier?
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Capillary endothelium with continuous tight junctions, astrocyte end foot, and basement membrane.
39
What is the blood brain barrier and what are its functions?
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1. tightly controlling substances that pass from blood to brain
2. protecting neurons/glia from toxins, infectious agents
3. prevents escape of neurotransmitters from site of production to general circulation
40
What are the key factors that determine the permeability of the blood brain barrier?
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Nonionized (lipid-soluble) drugs can cross the BBB easier than the ionized (water-soluble) drugs
41
What is meningitis?
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An inflammatory condition affecting the leptomeninges.
• Enterovirus (coxsackievirus and echovirus)
• Herpes simplex virus
45
Causes of fungal meningitis
Show answer
cryptococcus sp in immunocompromised patients
46
What are the two main pathways for pathogens to reach the leptomeninges?
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Direct and Hematogenous
47
What is the direct pathway for pathogens to reach the leptomeninges?
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Through the skin or nose, associated with anatomical defects or skull fractures
48
What is the hematogenous pathway for pathogens to reach the leptomeninges?
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Bacteria colonize the nasopharynx by attaching to epithelial cells, then gain access to the bloodstream and reach the choroid plexus
49
Classic symptoms of meningitis?
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Fever, headaches, and neck stiffness (nuchal rigidity)
50
What are the protective vaccines mentioned for bacterial meningitis?
Show answer
Meningococcal vaccines (N. meningitidis)
Hib vaccine (H. influenzae B)
pneumococcal vaccine (S. pneumoniae)
51
What is the treatment for bacterial meningitis?
Show answer
Dexamethasone (steroid to prevent leptomeninges injury) prior to antibiotics
52
What are the two main types of stroke?
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Ischemic and Haemorrhagic
53
Ischemic stroke subtypes?
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Thrombotic
Embolic
54
Haemorrhagic stroke subtypes
Show answer
Subarachnoid
Intracerebral
55
Ischemic stroke cause
Show answer
reduced or complete interruption of blood flow → rapid depletion of ATP stores → neural death
56
What is a thrombotic stroke?
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formation of a thrombus inside the cerebral vessels
leading to the occlusion of cerebral vessels
57
What are the symptoms of a thrombotic stroke?
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Symptoms may include headache, dizziness, confusion, loss of coordination, limb paralysis, and slurred speech. They can be sudden or gradual and often precede TIA.
58
What is an embolic stroke?
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Arterial occlusion caused by clot that originates somewhere else in body → ischemia
59
What are the symptoms of an embolic stroke?
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Symptoms include difficulty speaking
weakness or numbness
temporary paralysis
blurred vision
nausea
slurred speech
60
What is systemic hypoperfusion?
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Reduced blood flow to brain + organs due to issues in the systemic circulation
61
What causes systemic hypoperfusion?
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It can be caused by arrhythmias, reduced cardiac output, or bleeding.
62
What is the term for loss of the ability to understand or express language?
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Aphasia
63
What are the two phases of stroke management?
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Acute phase and chronic phase
64
Treatment of acute phase of stroke
Show answer
thrombolysis and endovascular surgery
65
Treatment of chronic phase of stroke
Show answer
physical therapy to minimize disability
pharmacological treatment to prevent recurrence
66
What are the four steps of the F.A.S.T. acronym for recognizing stroke symptoms?
Show answer
Face drooping, Arm weakness, Speech difficulty, Time to call 9-1-1
67
What is a hemorrhagic stroke?
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Bleeding in brain that prevents proper oxygenation → edema and brain damage
68
What is subarachnoid hemorrhage?
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Bleeding into subarachnoid space surrounding the brain
Cause: rupturing of an arterial aneurysm
69
What are the symptoms of subarachnoid hemorrhage?
Show answer
Sudden onset of severe headache (thunderclap headache)
blurred vision
loss of consciousness due to sudden rise in intracranial pressure
70
What is intracerebral hemorrhage (ICH)?
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Bleeding directly into brain parenchyma → localized hematoma
71
What are the symptoms of intracerebral hemorrhage?
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Rapid onset (minutes to hours)
headache, vomiting, decreased level of consciousness, and hemiplegia
72
What is the definition of Transient Ischemic Attack (TIA)?
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transient neurologic dysfunction due to a brief ischemic event
does not cause MI or tissue injury
73
What are the symptoms of TIA?
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Symptoms include weakness or numbness of the tongue, face, arm, or leg, trouble speaking normally, and double vision or trouble seeing in one or both eyes.
74
What is the function of the Peripheral Nervous System (PNS)?
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Carries messages to and from the Central Nervous System (CNS)
75
How are cranial nerves functionally divided?
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Sensory nerves, Motor nerves, Mixed (sensory & motor; common)
76
What are the two types of spinal nerve roots and what do they carry?
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Dorsal root (afferent/sensory) and ventral root (efferent/motor)
77
What is the primary motor cortext of the brain?
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Frontal lobe
Sends motor output to body parts
78
How does the size of the various parts in the Motor Homunculus relate to the cortical area?
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Size of the various parts is proportional to the cortical area devoted to them
79
Why do we have more neurons contributing to the face and hand movement compared to the feet?
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This enables fine control for face and hands
80
What are the sources of upper motor neurons?
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Cerebral cortex and deep nuclei of the brainstem
81
Where do lower motor neurons originate?
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Anterior (ventral) horns of the spinal cord
82
What is the function of descending somatic pathways?
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Carry motor signals from the brain to muscles to control voluntary movements
83
What is the function of the corticospinal tract?
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Controls muscle movement in the trunk and limbs
84
What is the Parietal Lobe and what does it contain?
Show answer
Somatosensory cortex, specifically the postcentral gyrus
85
What are Sensory Receptors?
Show answer
Specialized epithelial cells or neurons that respond to different environmental signals and transduce these signals into neural signals.
What is the role of neurotransmitter release at the synapse in the activation of taste receptors?
Show answer
Neurotransmitter release at the synapse activates the activation of taste receptors.
98
What are the five general taste categories?
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salt, sweet, sour, bitter, and umami
99
Which taste has the lowest threshold and which has the highest?
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Bitter has the lowest threshold, and sweet has the highest
100
What are the cranial nerves involved in taste sensation?
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CN VII, IX & X
101
What is taste adaptation?
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Within minutes of eating the same food, taste receptors start sending less signals to the brain.
102
How does hunger affect taste sensitivity?
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Hunger increases the sensitivity of taste receptors.
103
Disorders of taste
Show answer
• ageusia: absence of the sense of taste
• hypogeusia: diminished taste sensitivity
• dysgeusia: unpleasant perception of taste
104
What are the two main categories of pain?
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Acute and Chronic
105
What are nociceptors and what do they do?
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Sensory receptors that respond to noxious stimuli by triggering pain to protect the host
106
What are the three main types of nociceptors?
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Thermal, Mechanical, and Polymodal
107
What is the activation temperature for Thermal nociceptors?
Show answer
Skin temperatures above 45°C
Severe cold (<20°C)
108
What are polymodal nocireceptors
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senses combo of thermal/mechanical obnoxious stimuli
109
What does non-adaptive nature of nociceptors lead to?
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leads to unresolved causes and continuous pain
110
What are A delta fibers
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• thin myelinated fibers
• fast conduction speed
• fast pain perception
• sharp or piercing pain
• release glutamate
111
What are C fibers
Show answer
• unmyelinated axons with smaller diameter
• slow conduction velocity.
• slow pain perception
• dull, intense, diffuse, aching in nature
• releases a combination of glutamate and substance P