Week 2 - complete Flashcards
1
Q
What is the difference between statistical significance and clinical significance
A
Stats may not be clinical significant
2
Q
How do you calculate clinical value?
A
CV = therapeutic effect / cost
3
Q
What is PICO model used for?
A
Used to assess the relevance of a clinical study to determine if its relevant to a case/patient
4
Q
What does PICO stand for?
A
P: patient/population/problem
I: intervention
C: comparison/control
O: outcome
5
Q
What are cells made up of?
A
Macro and micromolecules
6
Q
What do enzymes do?
A
Lower Ea of metabolic process to increase the speed
7
Q
What factor can affect the speed of a chemical reaciton?
A
increased [substrate] = higher rate of product formation
8
Q
What do homeostatic control systems involve?
A
sensors, integrating centers, and effectors
9
Q
What are 4 characteristics of homeostatic control systems?
A
Competition, redundancy, priority, and adaptability
10
Q
Are positive feedback loops homeostatic? Why?
A
They are NOT homeostatic because the response REINFORCES the stimulus
11
Q
What is a way to remember ions in fluid in body compartments?
A
Salty banana: K inside, Na Cl outside
12
Q
What % of body weight is total body water?
A
60%
13
Q
what proportion of TBW is ICF and ECF?
A
ICF: 2/3 of TBW
ECF: 1/3 of TBW
14
Q
What ions are in ICF vs ECF
A
ICF: rich in K+
ECF: rich in Na, Cl, Ca
15
Q
What fractions make up ECF? In what proportions?
A
ECF = interstitial fluid (75%) and plasma (25%)
16
Q
What are some diseases that involve issues with ions?
A
Dehydration, Addison’s disease, diabetes insipidus
17
Q
What are some main functions of ions in the body?
A
Maintain tissue functions: RMP, muscle contraction, nutrient absorption
18
Q
What is osmosis?
A
Movement of water down its concentration gradient
19
Q
What is osmolality vs osmolarity
A
osmolality: number of osmols/kg water
osmolarity: number of osmols/L solution
20
Q
What is the osmolality of ECF?
A
~290mOsM
21
Q
What is tonicity?
A
THe ability of a solution to cause osmosis across a biological membrane
22
Q
What body fraction is affected by changes in osmolarity FIRST?
A
ECF first, which causes ICF to change
23
Q
Free water loss results in WHAT to ICF/ECF volume and osmolarity?
A
ECF becomes hyperosmotic/hypetonic -> cell osmolality increases but ICF and ECF dehydrate
24
Q
Water intoxication results in what for ICF and ECF?
A
ECF hypoosmotic/hypotonic -> ICF and ECF swell but osmolality decreases
25
For water overload or loss cases, what should you prescribe? why?
Hypo or hyperTONIC solutions, not hypo/hyperOSMOTIC solutions: because you need the solution to trigger changes in osmosis across the membranes
26
Solute loss triggers what in ICF and ECF?
ECF osmolality decreases -> water enters ICF -> ICF swells and ECF dehydrates
27
What does solute load trigger for ICF and ECF?
ECF osmolality increases -> H2O leaves ICF -> osmolality inc in both but ICF volume shrinks
28
Describe what cellular changes are induced by excess diarrhea/vomiting?
Fluid loss results in hypernatremia -> increase cell excitability -> seizures
Can also result in loss of electrolytes -> K+ shift from ICF to ECF -> decrease cell excitability -> fatigue
29
What are 3 types of cellular transport?
Simple diffusion, facilitated diffusion, active transport
30
What molecules use simple diffusion?
small lipophilic molecules, O2, CO2, steroid hormones, alcohol
31
What molecules use facilitated diffusion?
Large polar molecules
32
What 4 factors affect diffusion across bio membranes?
concentration gradient
lipid solubility
molecular size
membrane area
33
What are 2 types of active transport? Describe
Primary and secondary
Primary: uses ATP directly
Secondary: uses [gradient] generated from primary transport
34
What are 3 subtypes of secondary active transport? Describe
Uniport: one molecule moves
Symport: two molecules move in same direction
Antiport: two molecules move in opposite directions
35
What are 3 characteristics of carrier-mediated transport?
slower
prone to competition
limited by saturation
36
What are 5 types of cell signaling?
Autocrine
Paracrine
Cell-cell contract
Synaptic
Endocrine
37
Describe autocrine signaling
Within cell
38
Describe paracrine signaling
Chemical messengers, short distance
39
Describe cell-cell contact signaling
Intracellular mediators diffuse via gap junctions
40
What are 2 stains used in histology?
Hematoxylin and Eosin
41
Compare hematoxilyn vs eosin staining
Hematoxylin: basic stain that stains acids blue
Eosin: acidic stain that stains bases pink
42
What are 2 classifications of junctional complexes?
Anchoring junctions and communicating junctions
43
What are 4 types of anchoring junctions
Tight junctions, adherens junctions, desmosomes, hemidesmosomes
44
What is the function of tight junctions? Where are they located?
Barrier. Located at apical surface
45
What proteins are involved in tight junctions?
JAMs, claudins, occludins, F-actin
46
What are the 3 main functions of tight junctions
fence, barrier, signal transduction
47
What are adherens junctions for?
cell-cell adhesion
48
What are desmosomes for?
Cell-cell adhesions
49
What proteins are involved in adherens junctions vs desmosomes?
Adherens junctions: cadherins
Desmosomes: cadherins and intermediate filaments
50
What are hemidesmosomes for?
Cell basement membrane adhesion
51
Describe location of tight junctions, adherens junctions, desmosomes, and hemidesmosomes in cells?
Tight junctions: apical surface
Adherens and desmosomes: between cells (sides)
Hemidesmosomes: cell basement membrane
52
What are gap junctions used for
Communication
53
What proteins are invovled in gap junctions?
Connexins
54
Describe connexins?
Many different types which intermix to increase channel diversity. Different connexins = different molecules can pass through
55
Is epithelial vascular or avascular?
Avascular
56
What is epithelial tissue defined by?
Whether its single layer or multi-layer
57
What are the 3 types of single layer epithelial tissue?
Simple squamous, simple cuboidal, simple columnar
58
What do simple squamous epithelia look like? Where are they located?
Flat cells, in blood vessels and intestine epithelia
59
What are the main functions of simple squamous epithelia?
Diffusion and filtration, barrier
60
Describe simple cuboidal epithelia. Where are they located?
Round/cube shaped cells. Found in ducts, kidney tubules
61
What is the main function of simple cuboidal epithelia?
Absorption and secretion
62
Describe simple columnar epithelia. Where are they found?
Tall cells, nucleus at bottom. Found in intestinal villi, trachea inner lining
63
What are simple columnar epithelial cells for?
Absorption and secretion
64
What are the types of multi-layer epithelial tissue?
stratified squamous, pseudo-stratified, transitional
65
Stratified squamous epithelial tissue may include what?
Keratin
66
What is pseudo-stratified epithelial tissue for?
Motility
67
What is transitional epithelial tissue for? Located where?
Located in urinary bladder. For tissue distension
68
What are the 3 main components of connective tissue?
Cells, fibers, and non-fiber components
69
What is the structural organization of collagen?
microfibril -> fibril -> fiber ->bundle
70
What structure is a collagen microfibril?
Triple helix
71
Where is collagen synthesized?
RER of fibroblasts
72
What vitamin is invovled in collagen formation?
Vitamin C
73
What is one step of collagen synthesis involving Vitamin C?
Hydroxylation of Lys and Pro with Vitamin C
74
What are the steps of collagen synthesis? (What are the products)
Preprocollagen -> procollagen -> collagen fibril
75
How does procollagen become the collagen fibril?
Crosslinking at Lys residues
76
What are 2 collagen diseaeses?
Scleroderma and Ehlers-Danlos syndrome
77
What is scleroderma?
Overproduction of collagen
78
What is ehlers-danlos syndrome caused by? Symptoms?
Poorly aligned collagen fibrils resulting in joint hypermobility and skin hyper-elasticity
79
What is a main characteristic of elastin?
Ability to stretch and relax
80
What are 3 parts of elastin?
Proelastin, fibrillin, and MAGP
81
Where is elastin synthesized?
In RER of fibroblast
82
Describe elastin synthesis (2 seps)
1. Proelastin, fibrillin, and MAGP synthesized in fibroblast RER into immature elastic fiber
2. Crosslinking of fibers and assemble into mature elastin fibers
83
What is a disease of elastin? Describe
Marfan syndrome. Fibrillin mutation
84
What are the non-fiber components in connective tissue?
Semifluid gel of glycoproteins and proteoglycans
85
What are 2 glycoproteins in the non fiber component of connective tissue?
Fibronectin and laminin
86
What is the function of the non fiber components of connective tissue?
Allows diffusion of water, gases, nutrients, waste, water-soluble molecules, etc
87
What are the 3 main types of connective tissue?
Embryonic
Connective tissue proper
Specialized connective tissue
88
Describe embryonic CT (what cells?)
Mesenchyme: fibroblasts, adipocytes, osteoblasts, chrondroblasts, muscle cells
89
What are the 2 main types of connective tissue proper?
Loose CT and Dense CT
90
Where is loose CT located? What does it carry?
Under epithelia. Carries vessels and nerves
91
What are the cells in loose CT?
Fibroblasts, macrophages, leukocytes, plasma cells
92
What are the main fibers in Loose CT?
type 1 collagen, elastic fivers, T3C reticular fibers
93
What are the non-fiber componetns in loose CT?
glycosaminoglycan, hyaluron, proteoglycans, glycoproteins
94
What are the 2 main types of dense CT?
Irregular and regular
95
What are the main cells in dense irregular CT?
fibroblasts
96
What are the main fibers in dense irregular CT?
T1C and T3C woven together, some elastin
97
What are the main non-fiber components in dense irregular CT?
similar to loose CT, but less abundant
98
Where is dense irregular CT found in the body? What is its main characteristic?
organ capsules, reticular layer of dermis.
Resilient and protective
99
Where is dense regular CT found? What is its main characteristic?
tendons, ligaments, joints.
Highly stress resistant, low in cellular components
100
What are the main cells in dense regular CT?
Fibroblasts arranged in rows
101
What are the main fiber types in dense regular CT?
Mostly T1C, some elastin
102
What is the strongest type of collagen fiber?
T1C
103
What are the main non-fiber components in dense regular CT?
they are low in abundance = contributes to strength
104
What are 3 types of specialized CT?
Adipose, hematopoietic tissue, cartilage
105
What are 2 types of adipose?
WAT and BAT?
106
Where is hematopoeticic CT found?
bone marrow, lymph, spleen
107
What are the main cells in hematopoietic CT?
Reticular cells
108
What do reticular cells in hematopoietic CT do?
secrete and wrap around T3C bundles
109
What are the main fibers in hematopoietic CT?
T3C
110
What are the main non fiber components in hematopoietic CT?
Low abundance
111
What are 3 types of cartilage?
Hyaline, elastic, and fibrocartilage
112
What are the main functions of hyaline cartilage? (3)
1. shape and flexibility
2. models fetal bone development
3. smooth joint movement
113
What are the main functions of elastic cartilage?
shape and elasticity
114
What are the main functions of fibrocartilage? (3)
Resistance to compression, cushioning, tensile strength
115
Where is hyaline cartilage located?
trachea, bronchi, nose, ribs, articular ends, long bone epiphyseal plates
116
Where is elastic cartilage located?
epiglottis, larynx, pinnae of ear, auditory canal
117
Where is fibrocartilage located in the body?
Articular disks, vertebral disks, jaw, insertions of tendons
118
What is the main cell type in hyaline cartilage? How is it organized?
Chondrocytes organized into lacunae
119
What are lacunae AKA?
isogenous groups
120
What is the main cell type in elastic cartilage? How is it organized?
chondrocytes organized in lacunae
121
What is the main cell type in fibrocartilage? How is it organized?
Chondrocytes arranged in rows
122
What are the main fiber types in hyaline, elastic, and fibrocartilage?
Hyaline: T2C
Elastic: T2C, elastin
Fibrocartilage: T1C and T2C
123
what is articular cartilage?
Type of hyaline cartilage found in joints
124
What does articular cartilage lack? what is the impact?
lack perichondrium = poor regeneration
125
What is perichondrium?
CT that covers most cartilage in the body
126
What are the 2 layers of the perichondrium?
Fibrous layer and chondrogenic layer
127
What is the perichondrium fibrous layer?
rich in fibroblasts that secrete T2C
128
What is the function of the perichondrium chondrogenic layer?
Rich in chondroblasts tat secrete cartilage matrix
129
What is the growth mechanism/style of chrondrocytes? Describe
Appositional growth: chondrocytes divide and add layers
130
What is cartilage interstitial growth?
Chondrocytes divide within cartilage, forming isogenic groups
131
What are the 3 areas of bone? describe
Epiphysis: ends
Diaphysis: shaft/long part of bone
Metaphysis: between epiphysis and diaphysis
132
What is periosteum?
CT covering outside of bone, enriched in collagen
133
What is the endosteum ? where is it located
located inside bone. Made of reticular fibers and small amounts of CT running on inside of bone
134
What are 2 types of bone
compact/lamellar bone
cancellous/spongy/trabecular bone
135
Describe the organization of compact bone
Haversian systems/osteons: lamellae surround haversian canals, and volkmanns channels connect osteons
136
What are haversian canals?
Carry blood vessels in bone
137
What are sharpey's fibers?
Project into the outer circumferential lamellae of bone, connect periosteum to bone
138
Describe the structure of cancellous bone
Spicule nature: bone epiphysis is cancellous and interacts with cartilage. Has networks of anastomosing trabeculae that form interconnecting spaces containing marrow
139
What are the 4 types of bone cells?
Osteoprogenitor
Osteoblast
Osteocyte
Osteoclast
140
What are osteoprogenitor cells?
bone marrow derived MSC
141
Where do osteoprogenitor cells reside?
in periosteum and endosteum
142
What do osteprogenitor cells develop into?
Osteoblasts
143
What do osteoblasts do?
secrete bone matrix
144
what is bone matrix AKA?
osteoid
145
Where do osteoblasts reside?
in periosteum and endosteum osteogenic layer
146
What do osteoblasts initiate? How?
Initiate bone mineralization by secreting alkaline phosphatase
147
What do osteocytes do? (2)
Maintain calcification of bone
Form interconnected bone cell network
148
How do osteocytes develop?
From osteoblasts
149
Where are osteocytes located in bone? How do they interact?
They're enclosed in the bone matrix and contact each other via canaliculi gap junctions
150
What is one important feature of osteocytes?
Are mechanosensory, so regulate the activity of OBs and OCs
151
Where are osteoclasts found?
Howship's lacunae
152
Which bone cells are multinucleated vs single nucleated?
Osteoblasts and osteocytes: single nucleus
Osteoclast: multinucleated
153
What are osteoclasts derived from?
Fusion of macrophages
154
what is the function of OCs? How?
resorb bone by producing acid and metalloproteinases
155
which bone cells are stationary vs migratory?
stationary: OB, osteocyte
migratory: OC
156
What homeostatic functions are OCs important in? (2)
Bone remodelling and calcium/phosphate homeostasis
157
What are the 4 stages of bone remodelling
1. resting stage
2. bone resorption
3. transition
4. bone formation
158
Describe resting stage of bone remodelling
area of bone is targeted for OC recruitment and activation
159
Describe bone resorption stage of bone remodelling
OC migrate and digest bone, creating howship lacunae area
160
Describe transition stage of bone remodelling
OC are replaced by OB and bone matrix is synthesized
161
DEscribe bone formation stage of bone remodelling
OBs lay down new bone as needed
162
What are 2 types of bone remodeling?
intramembraneous ossification and endochondral ossification
163
What is intramembranous ossification?
Bone formation without cartilage template
164
What is endochondral ossification?
Bone formation with cartilage template
165
where do intramembranous vs endochondrial ossification take place?
Intramembranous: in flat bones (skull, pelvis)
Endochondral: in long bones, vertebrae, pelvis, base of skull
166
What is the cellular organization of skeletal muscle?
Myofibril -> muscle fiber -> fascicle
167
what are the perimysium, endomysium, and epimysium?
Perimysium wraps around fascicle
Endomysium surrounds each muscle fiber
Epimysium surrounds muscle
168
What are 3 characteristics of skeletal muscle?
striated, voluntary, multinucleated
169
What cells repair skeletal muscle? Where are they located?
Satellite cells repair. Located on periphery of fibers
170
what is the sarcomere?
Functional unit of skeletal muscle, Z line to Z line
171
What protein is in thin filaments? What band?
actin; I bands
172
What protein is in thick filament? What bands in sarcomere?
myosin; A band
173
what happens during muscle contraction (broadly)?
thin filaments slide over thick filament to shorten H zone
174
What shortens during muscle contraction?
I bands, H zone, and sarcomere
175
What happens after muscle contraction? What protein is involved, and where is it anchored?
Titin, which is anchored at Z line), pulls sarcomere back out
176
Describe the conduction system of skeletal muscle
Signal travels down T tubule from sarcoleemma and causes SR to release Ca2+
177
How are T tubules and SR organized in SM?
In a triad: 1 T tubule with 2 SR on the side
178
What other molecule is needed for muscle contraction?
ATP
179
what is the troponin complex made up of? Where is it located?
Made up of T, I, and C troponins. Located on top of tropomyosin along actin filament
180
What does the troponin complex regulate? How?
regulates the ability of myosin head groups to find actin to bind.
This happens because Ca2+ binds c-troponin, resulting in a conformational change in tropomyosin, which enables myosin to bind
181
Describe gap junctions in SM fibers
No gap junctions in SM fibers
182
which muscle fiber type is the largest? smallest?
Largest: skeletal muscle
Middle: cardiac
Smallest: smooth muscle
183
Which muscle types have gap junctions?
Smooth and cadiac
184
What are 2 characteristics of cardiac muscle cells?
Branching cardiomyocytes, single central nucleus
185
Describe how cardiac muscle cells regenerate
They dont
186
How are cardiac myocytes connected?
By gap junctions in intercalated discs
187
What are cardiac myocytes enriched with? what dies this so?
Enriched in adherens junctions and desmosomes to maintain 24/7 involuntary function
188
Describe SR in cardiac myocytes vs SM
SR is less developed and has fewer terminal cisternae
189
Compare T tubules in cardiac muscle vs skeletal muscle
T tubules are wider in CM and are in diads
SM are in triads
190
What are 3 characteristics of smooth muscle?
spindle shaped cells
single central nucleus
involuntary
191
Describe Z discs in smooth muscle cells
Have dense bodies with a-actinin to anchor actin INSTEAD of Z-discs
192
DEscribe t-tubules in smooth muscle
Have caveolae instead of T-tubules
193
What are 2 types of smooth muscle?
visceral and multi-unit
194
Compare visceral vs multiunit smooth muscle
visceral: spontaneous contractions, peristaltic motion (GI, uterus)
Multiunit: requires nervous stimulation to contract
195
How is nervous tissue organized?
Neurons are grouped into fasicles and surrouned by endoneurium. Perineureum surrounds fascicles; epineurium surrounds entire nerve
196
what does peripheral nerve tissue look like under the microscope
wavy tissue
197
What is the nerve cell body called?
Perikaryon
198
Where are organelles in the nerve cell?
In perikaryon and extending into dendrites
199
What is between perikaryon and axon?
Axon hillock
200
What are 3 types of neurons?
efferent, afferent, and interneurons
201
Which neurons are motor vs sensory?
motor: efferent.
sensory: afferent
202
Characterize efferent neurons
multinucleated from brain and ganglia to effector cells
203
characterize afferent neurons
pesudo-unipolar or bipolar in ganglia from effectors to CNS
204
Characterize interneurons
multipolar integration between sensory and motor neurons
205
how do neurons transmit signals (broadly)?
by delivering vesicles with NE or ACh along their axons to the synaptic cleft; these NTs then stimulate receptors on postsynaptic membrane
206
which nerves can/cant divide? how?
CNS nerves dont divide. PNS can repair by Schwann cells re-innervating tissue
207
what is the myelin sheath made up of?
concentric layers of lipids and proteins that insulate the axon
208
Describe how Schwann cells myelinate VS oligodendrocytes
one Schwann cell myelinates a segment of a single axon
one oligodendrocyte myelinates many axons
209
What are nodes of ranvier?
gaps between myelin cells that facilitate fast saltatory conduction
210
What are 3 types of supporting cells in the CNS?
astrocytes, microglia, and ependymal cells
211
What are main functions of astrocytes?
cells that form a scaffold network between capillaries, fiver, and neurons
maintain blood brain barrier
212
what is the function of microglia?
transform into phagocytic cells in damaged CNS. Form a defence system
213
What is the function of ependymal cells?
form single epithelium of ventricles and spinal canal
214
Which nervous system supporting cell is migratory?
microglia
215
Which nervous system supporting cell is ciliated? Why?
Ependymal cells
to help with propulsion of CSF
216
What is the first step in an AP?
When a nerve is sufficiently stimulated, the membrane polarizes from -70mV to -55mV
217
What is the second step in AP generation?
voltage gated Na channels rapidly open and Na enters the cell, depolarizing it to +45mV, initiating the AP
218
What is the third step in AP generation?
VG K channels open as Na channels are inactivated. K+ exits cell, which repolarizes to -70mV
219
What is the fourth step in AP generation?
K continues to leave cell as K channels slows close, membrane hyperpolarizes to -90mV
220
What is the fifth step in AP generation?
K channel close, and membrane returns to RMP as VG channels return to resting configuration
221
What is a relative vs absolute refractory period?
While VG Na channels are still inactivated, and only a greater than normal stimulus is able to stimulate an AP (relative only)
222
What is nerve conduction like in myopathy?
nerve conduction is normal but muscle amplitude is reduced
223
what is nerve conduction like in neuropathy?
nerve conduction typically abnormal, especially in demyelination cases
224
What is presynaptic rundown?
Sustained exercise results in decreased amount of ACh released per nerve impulse, resulting in fatigue
225
What is the first step in stimulating a muscle contraction
AP on motor nerve depolarizes the axon terminal and voltage gated Ca2+ channels open, resulting in Ca flowing in and ACh being released into the synaptic cleft
226
Describe the relationship between Ca and ACh in the axon terminal
larger [Ca] = more ACh release
227
What is the second step in stimulating a muscle contraction
ACh diffuses across synaptic cleft and binds to nicotinic receptors, resulting in the opening of chemically gated channels
228
What is the third step in stimulating a muscle contraction
Na flows into myocyte and K flows out, resulting in local depolarization
229
what is local depolarization at the motor end plate called?
end plate potential
230
What does an EPP trigger?
VG Na channels to open, triggering an AP
231
What is the fourth step in stimulating a muscle contraction
EPP triggers an APP
232
What is the fifth step in stimulating a muscle contraction
AP propagates down t-tubules, voltage sensors change shape and open Ca channels on SR
233
What is the sixth step in stimulating a muscle contraction
Ca2+ binds troponin, making tropomyosin uncover myosin binding sites on actin
234
What is the 7th step in stimulating a muscle contraction
Myosin binds actin, forming the crossbridge and a power stroke occurs -> muscle contracts
235
How long will a muscle continue to contract?
As long as the NMJ is stimulated, and ACh and Ca are available
236
How do muscles relax?
ACh-ase breaks down ACh in the NMJ, and ACh is taken back up in the axon terminal
237
What happens to Ca after a muscle contraction?
it is pumped back into the SR by CaATPase
238
What is dysfunctional in cystic fibrosis?
CFTR channel
239
What does CFTR dysfunction result in
Na and Cl ions and H2O remain inside cells rather than leaving them. In the respiratory tract this results in viscous mucus
240
What are some clinical manifestations of CF?
Thicker pancreas secretions = diarrhea
Thick mucus in lungs = blocks breathing
Sweat gland = higher sweat [Cl]
Male infertility
Liver cirrhosis
241
What is myasthenia gravis?
Reduced muscle contraction resulting from dysfunctional nicotinic receptors on motor end plate = reduced signal from ACh
242
What is a treatment for myasthenia gravis?
AChase inhibitors
243
What are 4 types of medical imaging?
Radiograph
CT
MRI
Ultrasound
244
Which type of medical imaging is best for viewing soft tissues?
MRI
245
How do radiographs distinguish anatomical structures?
based on different tissue opacities
246
What is summation?
Because radiographs are 2D, anatomical structures overlap
247
How many views do you need to visualize anatomy with a radiograph?
2
248
What is a CT scan?
Thin axial x-ray slices that form a 3D image
249
How is a CT better than a radiograph?
increased accuracy and precision for measuring small abnormalities
250
What is the unit of measurement in a cT scan?
voxel = small 2D measurement of volume
251
How does a MRI work?
Powerful magnet and radio waves visualize tissues based on H2O content by altering H atom polarization
252
What color do bones vs soft tissues appear in rads vs MRI?
rads: bones white, tissues grey
MRI: bones black, soft tissues lighter
253
How can you adjust MRI visualization? describe
T2 vs T1 weighting
T2 weighted: shows damaged/pathologic tissues best; bright signal
T1 weighted: black/grey image only
254
What are some drawbacks of MRI?
Most expensive, longest time to produce an image. Contraindicated with metal in body
255
How does US visualize tissues?
high frequency sound waves
256
What can US be used for (2)?
To assess anatomy or structure function (e.g. movement of blood)
257
How do air appear on US?
air appears bright
