The protective barriers to the CNS include the blood-brain barrier.
4
What are the two main divisions of the nervous system?
Show answer
Central nervous system and peripheral nervous system
5
What are the two main components of the central nervous system?
Show answer
Brain and spinal cord
6
What is the spinal cord and where does it extend?
Show answer
The spinal cord is a column of nerve tissue that extends within the vertebral canal. It occupies around two-thirds of the vertebral column and extends from the foramen magnum at the cervical region to the L1/L2 vertebrae.
7
What is the cauda equina and what does it consist of?
Show answer
The cauda equina is the lumbosacral nerve roots that travel inferiorly through the vertebral canal.
8
What is the function of the white matter in the spinal cord?
Show answer
The white matter contains myelinated ascending and descending fiber tracts of sensory and motor pathways, respectively.
9
What is the central canal in the spinal cord?
Show answer
The central canal contains cerebrospinal fluid (CSF).
10
What is the function of the anterior horn in the spinal cord?
Show answer
Conveys information from the motor cortex to the skeletal muscles (voluntary).
11
What is the function of the posterior horn in the spinal cord?
Show answer
Conveys sensory information to the sensory cortex of the brain.
12
What type of neurons are located in the lateral horn of the spinal cord?
Show answer
Preganglionic neurons of the autonomic nervous system.
13
What are the ascending spinal tracts and what do they transmit?
Show answer
Ascending spinal tracts include the dorsal column-medial lemniscus (transmits vibration, conscious proprioception, and fine touch) and the spinothalamic tract (transmits crude touch, pressure, pain, and temperature).
14
What are the descending spinal tracts and what do they control?
Show answer
Descending spinal tracts include the direct motor pathways (pyramidal tract, corticospinal tract, and corticobulbar tract) and the indirect motor pathways (extrapyramidal tracts, which control balance, posture, muscle tone, and coordination).
15
What are the two types of reflex responses mentioned in the slide?
Show answer
Involuntary reflex and acquired reflex
16
Which regions of the spinal cord are responsible for maintaining diaphragm and upper body motions, trunk movements, and lower limb movements respectively?
Show answer
Cervical region, Thoracic region, Lumbar region
17
What is a reflex arc?
Show answer
An involuntary rapid reflex mediated by the spinal cord before stimulating the brain.
18
What are the components of a reflex arc?
Show answer
Receptor + sensory neuron with one or more synapses to generate quick efferent output (via motor neuron + muscle)
19
What are the functions of the cervical region of the spinal cord?
Show answer
Controls sensation/movement of the neck and upper body, and autonomic functions like breathing and heart rate.
20
What are the consequences of a transection at C1-C3 in the cervical region?
Show answer
No function below the head and a ventilator is needed.
21
What is the difference in outcomes between a transection at C4-C5 and C6-C8 in the cervical region?
Show answer
C4-C5 results in quadriplegia, while C6-C8 leads to loss of lower limb function but some upper limb may be intact.
22
What are the protective layers of the central nervous system?
Show answer
The protective layers are the meninges, which include the dura mater, arachnoid mater, and pia mater.
23
What is the function of the meninges?
Show answer
The meninges provide a protective barrier and support the central nervous system.
24
What are the three layers of the meninges?
Show answer
Pia mater, arachnoid, and dura mater
25
What is the function of cerebrospinal fluid?
Show answer
Provide hydromechanical protection
26
What is cerebrospinal fluid (CSF)?
Show answer
CSF is a clear, colorless, and sterile ultrafiltrate of blood.
27
How much CSF circulates within the subarachnoid space and ventricles?
Show answer
Around 150 ml of CSF circulates.
28
What is the function of arachnoid villi?
Show answer
Arachnoid villi act as one-way valves between the subarachnoid space and the venous system.
29
What are the main components of cerebrospinal fluid (CSF)?
Show answer
Water, ions, glucose, small amounts of proteins, and small number of lymphocytes.
30
How is cerebrospinal fluid (CSF) sampled?
Show answer
CSF can be sampled via a lumbar puncture, also known as a spinal tap.
31
What are the functions of cerebrospinal fluid (CSF)?
Show answer
a) Buoyancy or hydromechanical protection to the brain and spinal cord. b) Providing nutrients and removing metabolic waste products. c) Aid in neurotransmitters and neuromodulators transport.
32
What is the choroid plexus?
Show answer
A highly vascular tissue that projects into the ventricles and is lined by ependymal cells.
33
What is the main function of the choroid plexus?
Show answer
To remove water and solutes from the blood and release it as cerebrospinal fluid (CSF).
34
How much CSF is produced per day by the choroid plexus?
Show answer
Around 500 ml of CSF per day.
35
What is the dura mater and what are its layers?
Show answer
The dura mater is the outermost layer of the brain meninges. It is formed by the periosteal layer (lining the skull) and an inner meningeal layer (dense collagenous tissue).
36
What is the subdural space and what does it contain?
Show answer
The subdural space is a narrow space between the dura mater and the arachnoid. It contains a scarce amount of cerebrospinal fluid (CSF).
37
What is the arachnoid mater?
Show answer
A thin, transparent layer that covers the subarachnoid space and surrounds the brain and spinal cord.
38
What is the subarachnoid space?
Show answer
Located between the arachnoid and pia mater, it contains CSF, blood vessels, and cranial nerves.
39
What is the function of the arachnoid villi?
Show answer
They act as a conduit for CSF to return to the venous circulation.
40
What is the pia mater?
Show answer
The innermost layer of the meninges, composed of thin connective tissue that covers the brain surface and extends into sulci, fissures, and around blood vessels.
41
What are the leptomeninges?
Show answer
The arachnoid mater and pia mater.
42
What is meningitis?
Show answer
An inflammatory condition that typically affects the leptomeninges.
43
What is the blood brain barrier?
Show answer
A functional barrier made up from capillary endothelium, astrocyte end foot, and basement membrane.
44
What are the components of the blood brain barrier?
Show answer
Capillary endothelium with continuous tight junctions, astrocyte end foot, and basement membrane.
45
What is the blood brain barrier and what are its functions?
Show answer
The blood brain barrier is a selectively permeable barrier that controls the passage of substances between the blood and the brain. Its functions include: 1) tightly controlling substances that pass from the blood to the brain, 2) protecting neurons and glia from bacterial toxins, infectious agents, and other exogenous substances, and 3) preventing the escape of neurotransmitters from their site of production in the CNS to the general circulation.
46
What are the key factors that determine the permeability of the blood brain barrier?
Show answer
The permeability of the blood brain barrier is determined by the size of the substance, its ionization state, and its lipid solubility. Nonionized (lipid-soluble) drugs can cross the BBB easier than the ionized (water-soluble) drugs.
47
What is Meningitis?
Show answer
Inflammation of the meninges, the protective membranes surrounding the brain and spinal cord.
48
What are Cerebrovascular Diseases?
Show answer
A group of disorders that affect the blood vessels in the brain, leading to stroke or cerebrovascular accidents.
49
What is a Cerebrovascular Accident (CVA) or Stroke?
Show answer
A sudden event that occurs when the blood supply to part of the brain is interrupted or reduced, causing brain cells to die.
50
What is meningitis?
Show answer
An inflammatory condition affecting the leptomeninges.
51
What are the types of meningitis?
Show answer
Bacterial, viral, and fungal meningitis.
52
What are the most common causes of bacterial meningitis?
Show answer
Streptococcus pneumoniae and Neisseria meningitidis.
53
What are the risk factors for bacterial meningitis?
Show answer
Exposure to endemic areas or vectors, age (infants and elderly), vaccine refusal, immunosuppressed states, and medical/health conditions such as malignancy, VP shunt, HIV, splenectomy, IV drug use, and renal failure.
54
What does VP shunt stand for in the context of bacterial meningitis risk factors?
Show answer
Ventriculoperitoneal shunt
55
What are the two main pathways for pathogens to reach the leptomeninges?
Show answer
Direct and Hematogenous
56
What is the direct pathway for pathogens to reach the leptomeninges?
Show answer
Through the skin or nose, associated with anatomical defects or skull fractures
57
What is the hematogenous pathway for pathogens to reach the leptomeninges?
Show answer
Bacteria colonize the nasopharynx by attaching to epithelial cells, then gain access to the bloodstream and reach the choroid plexus
58
What is CSF and what does it do?
Show answer
CSF stands for Cerebrospinal Fluid. It is a clear, colorless fluid that surrounds and protects the brain and spinal cord, providing cushioning and nourishment.
59
What are the steps involved in a lumbar puncture?
Show answer
The steps include: identifying the correct lumbar vertebrae, administering local anesthesia, inserting a needle into the spinal canal, and collecting cerebrospinal fluid for analysis.
60
What are the key components checked during a lumbar puncture?
Show answer
The key components checked are CSF clarity, pressure, culture, and CSF components such as WBCs (white blood cells) or protein.
61
What are the classic symptoms of the condition mentioned?
Show answer
Fever, headaches, and neck stiffness (nuchal rigidity)
62
What are some complications that can arise from the condition?
Show answer
Death, seizures, hydrocephalus, hearing loss
63
What are the protective vaccines mentioned for bacterial meningitis?
Show answer
Meningococcal vaccines (N. meningitidis), Hib vaccine (H. influenzae B), and pneumococcal vaccine (S. pneumoniae)
64
What is the treatment for bacterial meningitis?
Show answer
Treated with dexamethasone (steroid to prevent leptomeninges injury) prior to antibiotics course.
65
What is the fourth leading cause of death and major cause of disability?
Show answer
Stroke
66
How many people in the US have a stroke every year?
Show answer
> 795,000
67
What is the risk of having a stroke according to the slide?
Show answer
The risk of having a stroke varies with race and ethnicity (non-Hispanic Black adults have higher risk). The incidence of stroke tends to increases with age (>65Y).
68
What are the two main types of stroke?
Show answer
Ischemic and Haemorrhagic
69
What are the four subtypes of ischemic stroke?
Show answer
Thrombotic, Embolic, Subarachnoid, Intra-cerebral
70
List the risk factors for stroke mentioned in the slide.
Show answer
Prior transient ischemic stroke, hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, smoking, cardiovascular disease, recreational drug abuse, heavy alcohol consumption, and a family history of stroke.
71
What are the risk factors for cardiovascular conditions?
Show answer
Tobacco, diabetes, hyperlipidemia, hypertension, carotid artery disease, and atrial fibrillation.
72
What is hyperlipidemia?
Show answer
A condition characterized by elevated levels of lipids (fats) in the blood, often leading to atherosclerosis.
73
What is a thrombotic stroke?
Show answer
A thrombotic stroke is caused by the formation of a thrombus inside the cerebral vessels, leading to the occlusion of cerebral vessels.
74
What are the symptoms of a thrombotic stroke?
Show answer
Symptoms may include headache, dizziness, confusion, loss of coordination, limb paralysis, and slurred speech. They can be sudden or gradual and often precede TIA.
75
What is an embolic stroke?
Show answer
An embolic stroke is due to arterial occlusion caused by a clot that originates somewhere in the body, leading to ischemia.
76
What are the symptoms of an embolic stroke?
Show answer
Symptoms include difficulty speaking, weakness or numbness, temporary paralysis, blurred vision, nausea, and slurred speech.
77
What is systemic hypoperfusion?
Show answer
It is a condition where there is reduced blood flow to the brain and other organs due to issues in the systemic circulation, such as arrhythmias, reduced cardiac output, or bleeding.
78
What causes systemic hypoperfusion?
Show answer
It can be caused by arrhythmias, reduced cardiac output, or bleeding.
79
What is the term for difficulty in speaking clearly?
Show answer
Slurred Speech
80
What is the term for loss of the ability to understand or express language?
Show answer
Aphasia
81
What is the term for numbness on one side of the body?
Show answer
Numbness
82
What are the two phases of stroke management?
Show answer
Acute phase and chronic phase
83
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
84
What is the impact of a stroke?
Show answer
Long-term disability impacting self-care ability
85
What is a hemorrhagic stroke?
Show answer
Bleeding in the brain that prevents proper oxygenation leading to edema and brain damage.
86
What is subarachnoid hemorrhage?
Show answer
Bleeding into the subarachnoid space surrounding the brain, mostly caused by rupturing of an arterial aneurysm.
87
What are the symptoms of subarachnoid hemorrhage?
Show answer
Sudden onset of severe headache (thunderclap headache), blurred vision, and loss of consciousness due to sudden rise in intracranial pressure.
88
What is intracerebral hemorrhage (ICH)?
Show answer
Bleeding directly into the brain parenchyma leading to a localized hematoma that enlarges through blood accumulation.
89
What are the risk factors for intracerebral hemorrhage?
Show answer
Chronic hypertension or hypertensive crisis (BP > 180/120), bleeding disorders, drug use (mostly amphetamines and cocaine), and vascular malformation.
90
What are the symptoms of intracerebral hemorrhage?
Show answer
Rapid onset (minutes to hours) may include headache, vomiting, decreased level of consciousness, and hemiplegia (one-sided paralysis).
91
What is the definition of Transient Ischemic Attack (TIA)?
Show answer
TIA is a transient neurologic dysfunction due to a brief ischemic event that does not cause acute infarction or tissue injury.
92
What are the symptoms of TIA?
Show answer
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.
93
What are the two main divisions of the nervous system?
Show answer
Central nervous system and peripheral nervous system
94
What are the components of the central nervous system?
Show answer
Brain and spinal cord
95
What are the three divisions of the peripheral nervous system?
Show answer
Autonomic nervous system, somatic nervous system, and enteric nervous system
96
What is the function of the Peripheral Nervous System (PNS)?
Show answer
Carries messages to and from the Central Nervous System (CNS)
97
What are ganglia in the context of the PNS?
Show answer
Clusters of functionally related neuronal cell bodies along with their glial cells
98
What are the 12 pairs of cranial nerves?
Show answer
I - Olfactory, II - Optic, III - Oculomotor, IV - Trochlear, V - Trigeminal, VI - Abducens, VII - Facial, VIII - Vestibulocochlear, IX - Glossopharyngeal, X - Vagus, XI - Accessory, XII - Hypoglossal
99
How are cranial nerves functionally divided?
Show answer
Sensory nerves, Motor nerves, Mixed (sensory & motor; common)
100
What are the two types of spinal nerve roots and what do they carry?
Show answer
Dorsal root (afferent/sensory) and ventral root (efferent/motor)
101
How many pairs of spinal nerves are there and what are they called?
Show answer
31 pairs, called C8, T12, L5, S5, and C1
102
What is the primary motor area of the brain?
Show answer
The primary motor area is responsible for controlling voluntary movements.
103
Where is the primary motor area located in the brain?
Show answer
The primary motor area is located in the frontal lobe.
104
What is the primary motor cortex and where is it located?
Show answer
The primary motor cortex is the frontal lobe, specifically in the coronal section.
105
How does the size of the various parts in the Motor Homunculus relate to the cortical area?
Show answer
The size of the various parts is proportional to the cortical area devoted to them.
106
Why do we have more neurons contributing to the face and hand movement compared to the feet?
Show answer
This enables fine control for face and hands.
107
What are the sources of upper motor neurons?
Show answer
Cerebral cortex and deep nuclei of the brainstem
108
Where do lower motor neurons originate?
Show answer
Anterior (ventral) horns of the spinal cord
109
What is the function of descending somatic pathways?
Show answer
Carry motor signals from the brain to muscles to control voluntary movements
110
What is the function of the corticospinal tract?
Show answer
The corticospinal tract controls muscle movement in the trunk and limbs.
111
Where are the cell bodies of upper motor neurons located?
Show answer
The cell bodies of upper motor neurons are located in the motor cortex.
112
What happens to the axons of upper motor neurons after they cross over at the medulla?
Show answer
The axons of upper motor neurons cross over at the medulla to the contralateral side.
113
What is the Parietal Lobe and what does it contain?
Show answer
The Parietal Lobe is the Somatosensory cortex, specifically the postcentral gyrus.
114
How does the size of the cortical receiving area in the Somatosensory cortex relate to the number of receptors?
Show answer
The size of the cortical receiving area is proportionate to the number of receptors.
115
What are Sensory Receptors?
Show answer
Specialized epithelial cells or neurons that respond to different environmental signals and transduce these signals into neural signals.
116
What are Mechanoreceptors?
Show answer
Mechanoreceptors are sensory receptors that respond to touch and pressure, with examples including free nerve endings in the skin, joint receptors, stretch receptors in muscle, and baroreceptors in the carotid sinus.
117
What is the function of the spinothalamic tract?
Show answer
Transfers sharp pain and heat sensation from the affected organ to the brain.
118
What is a first-order neuron in the context of the spinothalamic tract?
Show answer
A sensory neuron that originates from the skin receptors, with cell bodies in the dorsal root ganglia in the spinal cord.
119
What happens to the axons of the second-order neurons in the spinothalamic tract?
Show answer
Decussate via the anterior white commissure of the spinal cord and ascend contralaterally towards the thalamus.
120
What is the function of the second order neuron in the somatosensory pathway?
Show answer
Carry input from the spinal cord to the thalamus.
121
Where are the cell bodies of the third order neuron located?
Show answer
In the thalamus.
122
What is the function of the fourth order neuron in the somatosensory pathway?
Show answer
Cell bodies are in the appropriate sensory area of the cortex.
123
What does 'Taste Sensation' refer to in the context of dental medicine?
Show answer
A term used to describe the perception of taste in the mouth, often related to dental health and taste disorders.
124
What institution is mentioned at the bottom of the slide?
Show answer
California Northstate University College of Dental Medicine.
125
What are the three major types of papillae on the tongue and what do they detect?
Show answer
Fungiform: anterior two-thirds, detects salty, sweet, and umami; Circumvallate and foliate: posterior third, detects sour and bitter.
126
What is the function of microvilli in receptor cells?
Show answer
To increase the surface area.
127
What is the function of the taste bud in the oral cavity?
Show answer
The taste bud is composed of specialized epithelial cells with microvilli that project into the taste pore, containing taste receptor cells and basal cells.
128
How long can taste cells survive in the taste bud?
Show answer
Taste cells can survive for about 10 days.
129
What role does saliva play in the taste process?
Show answer
Saliva in the oral cavity acts as a solvent for tastants and helps the chemicals diffuse to the taste receptor.
130
What is the pathway of taste signals from the tongue to the gustatory cortex?
Show answer
Taste signals travel via the respective afferent cranial nerve to the medulla, then to the thalamus, and finally to the gustatory cortex.
131
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.
132
What are the five general taste categories?
Show answer
salt, sweet, sour, bitter, and umami
133
What does taste threshold refer to?
Show answer
The minimum concentration at which a substance can be perceived
134
Which taste has the lowest threshold and which has the highest?
Show answer
Bitter has the lowest threshold, and sweet has the highest
135
What are the cranial nerves involved in taste sensation?
Show answer
CN VII, IX & X
136
What is taste adaptation?
Show answer
Within minutes of eating the same food, taste receptors start sending less signals to the brain.
137
How does hunger affect taste sensitivity?
Show answer
Hunger increases the sensitivity of taste receptors.
138
What are the three main disorders of taste mentioned in the slide?
Show answer
ageusia, hypogeusia, dysgeusia
139
What are some causes of taste disorders mentioned in the slide?
Nociceptors are sensory receptors that respond to noxious stimuli by triggering pain to protect the host.
143
What are the three main types of nociceptors?
Show answer
The three main types of nociceptors are Thermal, Mechanical, and Polymodal.
144
What is the activation temperature for Thermal nociceptors?
Show answer
Thermal nociceptors are activated by skin temperatures above 45°C or by severe cold (<20°C).
145
What are nociceptors and where are they found?
Show answer
Nociceptors are free nerve endings found in the skin and other tissues.
146
What stimuli do nociceptors respond to?
Show answer
Nociceptors respond to thermal, mechanical, and chemical stimuli.
147
What is the non-adaptive nature of nociceptors and what does it lead to?
Show answer
The non-adaptive nature of nociceptors leads to unresolved causes and continuous pain.
148
What are A delta (Aδ) fibers and what do they do?
Show answer
A delta (Aδ) fibers are relatively thin myelinated fibers (1-4 um) with fast conduction speed. They are responsible for the fast pain perception, transmitting localized fast or first pain sensation which is sharp or piercing pain.
149
What is the role of Aδ fibers in pain perception?
Show answer
Aδ fibers release glutamate that triggers the 'first pain'. They help in detecting the pain site and intensity, making it easily localized.