Exam 2 Practice Flashcards
(340 cards)
1
Q
The I-band of cardiac muscle is mostly
A
Actin
2
Q
Dead cardiac muscle cells are replaced by
A
Scar tissue made by local fibroblasts
3
Q
The impulse generated by the A-V node is conducted to the apex of the heart by
A
Purkinje fibers
4
Q
The membranes of the sacroplasmic reticulum are continuous with
A
None of the above
5
Q
The sacroplasmic reticulum of skeletal muscle fibers contain more _____ than most fast-twitch fibers
A
Myoglobin
6
Q
The average width of a skeletal muscle fiber is
A
0.06 mm (60 um)
7
Q
The dystroglycans in the sacrolemma link dystrophin to the
A
Basement membrane
8
Q
The myosin-binding site of skeletal muscle actin is blocked by
A
Tropomyosin
9
Q
The diagram represents a sacromere of _____ muscle
A
Cardiac
10
Q
The sacrolemma of a skeletal muscle fiber is _____ unit membranes
A
1
11
Q
The thin filaments near the cell membrane are linked to membrane glycoproteins by
A
Dystrophin
12
Q
The T-tubule membrane is a continuation of the
A
Cell membrane
13
Q
Alpha-actinin is the major component of the _____ of skeletal muscle
A
Z-line
14
Q
Almost all of the sacroplasmic reticulum of a skeletal muscle is between
A
Myofibrils
15
Q
Red (type I) skeletal muscle fibers have more _____ than white (type II) fibers
A
Myoglobin
16
Q
One feature of cardiac muscle that is never seen in skeletal muscle is
A
Branching of myofibrils
17
Q
The thick filaments of cardiac muscle are made of
A
Myosin
18
Q
The Ca++ for phasic contraction of smooth muscle comes from the
A
Tissue fluid
19
Q
Gap junctions are always found between the cells of
A
- Cardiac muscle
- Single unit smooth muscle
20
Q
Type I skeletal muscle fibers contain more _____ than type IIx skeletal muscle fibers
A
- Dystrophin
- Dystroglycan
- Mitochondria
21
Q
The Ca++ channels of the sacroplasmic reticulum are irreversibly opened by
A
Ryanodyne
22
Q
Short workouts with heavy weights cause skeletal muscle fibers to
A
Add more myofibrils
23
Q
The calcium for ions necessary for contraction of skeletal muscle are stored in the
A
Sacroplasmic reticulum
24
Q
The T-tubule in skeletal muscle usually has a cisterna of the sacroplasmic reticulum
A
On each side
25
Short workouts with heavy weights stimulate the
Multiplication of white skeletal muscle fibers
26
The artist intended this line to represent a
Myosin thick filament
27
Smooth muscle in myosin is identical to
None of the above
28
Ventricular cardiac muscle has more _____ than atrial cardiac muscle
T-tubules
29
The quickest contraction human muscle is
Extra-ocular skeletal muscle
30
White skeletal muscle fibers can be converted to red skeletal muscle fibers by
Marathons
31
Protein that links to integrins on membrane
Vinculin
32
The smooth muscle of muscular artery is
Single unit
33
Gap junctions permit the cell-to-cell diffusion of
Light metal ions
34
The sacroplasmic reticulum of ventricular cardiac muscle releases Ca++ in response to
Ca++ entering the cytosol from the T-tubule
35
The highest concentrations of myoglobin are found in
Cardiac muscle fibers
36
Dystrophin in the sacrolemma connects intracellular
Dystrophin with extracellular laminin
37
A long string of sacromeres surrounded by sacroplasmic reticulum is a
Myofibril
38
The "latch effect" in smooth muscle ends when _____ breaks their actin-myosin complex
Caldesmon
39
The smooth muscle of the stomach is
Single unit
40
A small infraction in cardiac muscle causes
Mitosis in adjacent cardiac muscle cells
41
The T-tubules of ventricular cardiac muscle fibers are _____ the T-tubules of skeletal muscle
Wider than
42
The proximate cause of the opening of ryanodine receptors in skeletal muscle is
Conformational change in the dihydropyridine receptors
43
The dystroglycans in the sacrolemma link dystrophin to the
Basement membrane
44
A smooth muscle fiber is always surrounded by
Type IV collagen
45
Depolarization of the T-tubule membranes of a skeletal muscle fiber rearranges the _____ so that Ca++ can sacroplasmic reticulum
Ryanodyne receptor
46
A sacromere is
All of the filaments between 2 Z-lines
47
Bacterial lipopolysaccharides cause neutrophils to produce
Leukotriene
48
The basophilic granules of neutrophils contain
Myeloperoxidase
49
COX-1 converts arachidonic acid to
Thromboxane A2
50
Blood has a significantly higher osmotic pressure than tissue fluid because
It contains more protein
51
Selectins on the cell membranes endothelial cells adhere to integrins on the cell membranes of
Leukocytes
52
A large vein always has
Only longitudinal smooth muscle in the adventitia
53
The protein C/protein S complex on endothelial cell membranes
Inhibits clotting
54
The internal carotid is a(n)
Elastic artery
55
When blood passes through a normal heart, it is in contact with
Endothelial cells
56
The diameter of a red blood cell is
7 um
57
The cell at the tip of the arrow is a
Pericyte
58
Neutrophil myeloperoxidase uses superoxide to produce
Hypochlorous acid
59
It is currently believed that new endothelial cells can be recruited from
Circulating HSC
60
Endothelial cells lower local blood pressure by secreting
Nitric oxide
61
Interleukin-1 causes endothelial cells to produce prostacyclin to
Prevent blood coagulation
62
The valves of veins are opened and closed by
Local differences in blood pressure
63
Vasa vasorum are found in the advaentitia of only
Elastic and muscular arteries and large veins
64
Most of the elastin in the media of the aorta is in the form of
Concentric sheets
65
Most men, but hardly any women, have _____ in the basal half of the mitral valves
Cardiac muscle
66
The bore (lumen) diameter of blood capillaries is from _____ to _____ um
6 to 10
67
Because COX-2 inhibitors block the production of prostacyclin they can cause
Intravascular coagulation
68
Longitudinal fascicles of smooth muscle are typically found in the adventitia of
Superficial veins
69
The skeleton of a youthful human heart is
Dense fibrous connective tissue
70
E-selectin (ELAM) on the cell membranes of endothelial cells adheres to _____ on the cell membranes of leukocytes
Integrins
71
Vasa vasorum are found in the _____ of elastic arteries
Adventitia and media
72
Water enters the venous end fo a capillary because of the
Osmotic pressure of the blood
73
The diameter of the lumber of a vein is usually _____ the diameter of the lumen retry it accompanies
Larger than
74
The growth of new capillaries is promoted by
VEGF
75
A cell in bone marrow that has specific granules and a deeply indented nucleus is a
Metamyelocyte
76
It is currently believed that new, fully competent endothelial cells can be recruited from
- HSC
- CMP
- CLP
- Smooth muscle cells
(All of the above)
77
In order to survive at all, a T-lymphoblast must interact with a ___ in the thymic cortex
Nurse cell
78
The blood-thymus barrier in the cortex of the thymus is maintained by
Epithelial reticular cells
79
Splenic macrophages are the body's principle defenders against
Blood parasites
80
The movement of lymphocytes across the walls of the high endothelial venules of lymph 1/1 nodes is facilitated by _____ in the cell membranes of the endothelial cells
Selectins
81
How many afferent lymphatics does the spleen have?
None
82
Most of the macrophages of the spleen are in the
Red pulp
83
Langerhans cells are antigen-presenting cells in the
Epithelium of the tonsils
84
The largest object that can pass between the endothelial cells of the sinuses of the spleen is a
Red blood cell
85
The stroma of the red pulp of the spleen is
Reticular connective tissue
86
The follicular dendritic cells of lymph nodes are descended from
Reticular cells
87
CD4+CD8- thymocytes usually become
Th cells
88
The first test of a thymocyte's potential usefulness is its ability to interact with the ____ of a “nurse cell”
MHC
89
The epithelial reticular cells of the thymus secrete
Type IV collagen
90
Interleukin-3 (IL-3) is secreted by
T-lymphocytes
91
Platelets are produced by
The breakup of megakaryocytes
92
A hemopoietic stem cell
Gives rise to all kinds of blood cells
93
Platelets have no (repeat no)
Nuclei
94
Contact with collagen I or collagen III causes platelets to produce
Thromboaxane A2
95
Treg-lymphocytes Inactivate
Anti-self Tc and Th-lymphocytes
96
The most important stimulus for T-lymphocyte development is
Interleukin-6
97
The first test of a T-lymphoblast's potential usefulness is its ability to interact with the MHC-I of
A thymic nurse cell
98
Erythropoietin is secreted by the
Kidneys
99
The common stem cell for endothelial cells and blood cells is
A hemangioblast
100
Antigen-presenting cells are the final result of the maturation of
Monocytes
101
Antigen antibody complexes are removed from blood and tissues primarily by
Eosinophils
102
The cytoplasm of proerythroblasts is basophilic because it contains a great deal of
RNA
103
The reticular cells of bone marrow are the only source of
SCF
104
Thrombopoiten is removed from the blood by
Platelets
105
The epithelial reticular cells of of the thymus secrete
Type IV collagen
106
A thymocyte that interacts with MHC II and expresses CD4 usually becomes a
Th
107
Most of the plasma cells in the tonsils secrete
IgA
108
Worn out and infected erythrocytes are destroyed by
Splenic macrophages
109
Platelets are produced by
The breakup of megakaryocytes
110
A CFU-S is descended from
- Another CFU-S
- Hemangioblasts
(either of the above)
111
Thymic stromal lymphopoietin is secreted by
Hassal's corpuscles (ERC-VI)
112
The blood supply of a lymph node
Comes from an arteriole
113
The denser regions in the medulla of a lymph node are
Medullary cords
114
The smallest arterioles of the spleen (the penicillar arteries) empty directly into
Spaces in the red pulp
115
The follicles of the spleen are part of
The white pulp
116
Human epithelia usually contain
Antigen-presenting cells
117
Since they carry out most of the activity of the red pulp of the spleen, _____ are its parenchyma
Macrophages
118
The movement of lymphocytes across the walls of the high endothelial venules of lymph nodes is facilitated by _____ in the cell membranes of endothelial cells
Selectins
119
Most of the plasma cells under mucous membranes secrete
IgA
120
The sclera is
Dense regular connective tissue
121
Except for the capsule and trabeculae, the stroma of a lymph node is
Reticular connective tissue
122
Blood enters the venous sinuses of the spleen directly from
Spaces in the red pulp
123
The few anti-self Th cells that escape from the thymus are inactivated by
Thymic humoral factor y2
124
The antigenic specificity of a thymocyte is determined by
Multiple crossovers within the T-cell receptor genes
125
IL-1 stimulates the production of ___________ by endothelial cells
Prostacylin
126
Thymic humoral factors are secreted by the
Epithelial reticular cells of the thymus
127
The principal function of Treg-lymphocytes is to
Inactivate anti-self Th-lymphocytes
128
Splenic macrophages are concentrated
Around the venous sinuses
129
Erythropoietin is secreted by
Fibroblasts in the kidneys
130
Water is driven out of the arterial end of a capillary by the
Blood pressure
131
Valves are found in
Veins and lymphatics
132
B-lymphocytes respond best to antigens when they receive them directly from a
Th cell
133
Production of leukocytes is promoted by
- IL-3
- IL-6
- SCF
- GMCSF
(All of the above)
134
A thymocyte that interacts with MHC II and expresses CD4 usually becomes a
Th
135
The white pulp of the spleen is mostly
Lymphocytes
136
Most of the plasma cells in a lymph node are found in the
Medullary cords
137
The stroma of the tonsils is
Areolar connective tissue
138
The crypts of the tonsils are open to the
Pharynx
139
Nurse cells are found in
The cortex of the thymus
140
Eosinophils secrete their granules to damage or destroy
Metazoan parasites
141
The basophilic granules of neutrophils contain myeloperoxidase which
Generates superoxide ion
142
The diameter of an erythrocyte is
7 um
143
Closed fenestrae are found in the capillary endothelium in the
Digestive tract
144
Blood clots are naturally dissolved by
Platelets
145
In venous blood, a normal erythrocytes is a
Biconcave disk
146
Defendins and phospholipases are found in the granules of
Neutrophils
147
Neutrophils are drawn to an infected area by
Leukotriene
148
In a middle aged (30 to 60 year old) human, hemopoesis takes place in the
Bone marrow of the axial skeleton
149
The first step in the differentiation of a hemocytoblast is differentiation into
CFU-L or CFU-My
150
Interleukin-3 is also known as
Leukopectin
151
A megakaryocte can produce
Innumerable cohorts of platelets
152
A BFU (burst forming unit) divides to become a clone (or colony) of
Proerythroblasts
153
Th and Tc can be distinguished by their
Membrane receptors
154
Ts lymphocytes
Inactivate Tc and Th lymphocytes
155
Most of the plasma cells in Peter’s patches secrete
IgG
156
The endothelium of a capillary is supported by
A basal lamina
157
Transcytosis is the only means of moving large molecules across the wall of a
Right capillary
158
Fenestrae closed by thin diaphragms are found in the capillary endothelium in the
Mucosa of the intestine
159
Platelets undergo shape change and degeneration when
They make contact with type I collagen
160
The basophils comes granules of neutrophils contain an enzyme that
Generates oxygen free radicals
161
Much of the human resistance to cancer lies in the ability of _____ to recognize and kill cancer cells
NK cells
162
The capillaries in the cortex of the rhymes
Have a tight junction between the endothelial cells
163
A germinal center of a lymph node is a site of
B-lymphocyte multiplication
164
Granulocyte-monocyte colony stimulating factor (GMCSF) is secreted by
Macrophages
165
Erythropoietin is secreted by the
Juxtaglomerular cells of the kidneys
166
B-lymphocytes become mature in the
Bone marrow
167
In addition to elastin, the media of the aorta contains
Collagen I and III
168
The cardiac muscle fibers of the atria secrete a hormone that
inhibits renal Na+ and water resorption
169
The heart is lined by
Endothelial cells
170
Gap junctions are always found between the cells of
Single unit smooth muscle
171
Myofibrils are separated from each other by
Sacroplasmic reticulum
172
Smooth muscle cells are separated from each other by
A basement membrane
173
Gap junctions permit the cell-to-cell diffusion of
Light metal ions
174
Gap junctions transmit ______ from one cell to another
Small ions
175
Long bouts of exercise against low resistance (e.g., training for a 3000 meter race or 1500 meter freestyle swimming) causes
Addition of more myoglobin to slow twitch muscle fibers
176
The thin filaments just beneath the sarcolemma of a skeletal muscle cell are linked to laminin in its basal lamina by
Dystrophin and dystroglycan
177
Although skeletal muscle fibers vary greatly in LENGTH, most are in the ____ range
5 to 450 mm
178
Although skeletal muscle fibers vary in WIDTH, most are in the ____ range
30 to 150 um
179
The most important refracting media of the eye are the lens and the
Aqueous humor
180
Myopia is the result of the eyeball being __________ for its optical system
Too long
181
Cones are absent from the
- Margin of the visual retina
- Blind spot
(Both of the above)
182
The choroid lies between the
Retina and the sclera
183
Aqueous humor normally flows from the posterior chamber to the anterior chamber via the
Pupil
184
The principal protein of the lens capsule is
Collagen IV
185
Cerebrospinal fluid returns to the blood through
Arachnoid villi
186
White matter is mostly
Myelinated axons
187
Perineurium is made by
Fibroblasts
188
The perikarya of primary sensory neurons for touch are found in
Dorsal root ganglia
189
The astrocyte "feet" around brain capillaries retract to create a perivascular space during
Sleep
190
Cut axons in the spinal cord do not regenerate because _____ inhibit growth
Glycoproteins in the myelin made by oligodendrocytes
191
Almost all of the capillaries in the brain are ______ capillaries
Tight
192
NG2 cells often become
Oligodendrocytes
193
It is exceedingly rare for an "axon hillock" to contain
Ribosomes
194
A bare majority of the cells in the brain are
Astrocytes
195
The cytoplasm of a normoblast is acidophilic because it contains a great deal of
Hemoglobin
196
Fast-twitch (type IIx) skeletal muscle fibers have more _____ than slow-twitch (type I) fibers
Myosin
197
Endurance exercise causes skeletal muscle fibers to
Make more myoglobin
198
Cardiac muscle fibers are electrically coupled by
Gap junctions
199
Depolarization of the T-tubule membranes of a skeletal muscle fiber repositions the ryanodyne receptor so that _____ can leave the sarcoplasmic reticulum
Ca++
200
In skeletal muscle, a “triad” is a group of
One t-tubule and two cisternae of sarcoplasmic reticulum
201
The tropomyosin in skeletal muscle is part of the
Thin filaments
202
A motor unit is
All skeletal muscle cells served by the same axon
203
The peripheral branch of the axon of a sensory neuron normally carries messages
Toward the cell body
204
NG2 glia often become
Astrocytes
205
The fovea of the retina contains only
Cones
206
For a human to focus on an object close at hand his lens must
Thicken
207
Aqueous humor normally flows from the posterior chamber to the anterior chamber via the
Pupil
208
The substantia propria of the cornea is
Dense regular connective tissue
209
The multiplication of neuroblasts is most evident in the
Hippocampus
210
Cerebrospinal fluid is secreted by
Choroid plexus cells
211
The radial nerve is composed of
Only the axons of neurons in the spinal cord and posterior root ganglia
212
Epineurium is made by
Fibroblasts
213
A tripartite synapse is the junction of processes of 2 neurons and one
Astrocyte
214
Nissl bodies are
Concentrations of rough endoplasmic reticulum
215
The crypts of the tonsils are open to the
Pharynx
216
IL-1 stimulates the production of prostacyclin by
Endothelial cells
217
Longitudinal smooth muscle fibers are commonly found in the adventitia of
Veins
218
The vessel delivering blood to the medial side of the big toe is a
Muscular artery
219
A smooth muscle cell is usually __ as long as it is wide
10 times
220
During tonic contraction smooth muscle often displays a _____ effect
Latch
221
Smooth muscle myosin is identical to
No other myosin
222
The first effect of exercise on cardiac muscle is
An increase in the number of capillaries feeding it
223
Fast-twitch human skeletal muscle fibers contain more ______ than slow-twitch fibers
Glycogen
224
The T-tubules of skeletal muscle are located at the edges of the
A-I junctions
225
Endothelial cells line the lumen of
- Arteries
- Veins
- Heart
(All the above)
226
The endothelium of a capillary is supported by
- A basal lamina
227
Fenestrae closed by thin diaphragms are found in the capillary endothelium in the
Mucosa of the intestine
228
The basophilic granules of neutrophils contain an enzyme that
Generates oxygen free radicals
229
The capillaries in the cortex of the thymus have
Tight junctions between endothelial cells
230
Which retinal cells have the longest axons?
Ganglion cells
231
The ability of the lens to focus on nearby objects depends on
The elasticity of the lens capsule
232
The layer of the cornea between Bowman’s membrane and Descemet’s membrane is
Dense regular connective tissue
233
Aqueous humor flows from the anterior chamber to the canal of Schlemm via the
Trabecular meshwork
234
The surface area of smooth muscle fiber is greatly increased by
Caveoli
235
Smooth muscle cells are separated from each other by
Basement membrane
236
A smooth muscle is capable of phasic contraction if it has
Voltage gated cation channels
237
Dystrophin links the dystroglycans in the cell membrane to
Adjacent thin filaments
238
High concentrations of myoglobin are typical of
- Red (type I) skeletal muscle fibers
- Intermediate (type IIa) skeletal muscle fibers
(Both of the above)
239
The microtubules of an axon serve as
Tracks for transport of secretory vesicles
240
Nissl bodies are
Concentrations of rough endoplasmic reticulum
241
The capillaries of the brain are surrounded by
The feet of astrocytes
242
Schwann cells are separated from each other by
Nodes of ranvier
243
Dorsal root ganglia contain
- Schwann cells
- Satellite cells
- Perikarya of neurons
(All of the above)
244
IL-1 causes upregulaiton of _____ in endothelial cells
COX-II
245
The precursor of a red blood cell loses its nucleus during the transition from
Normoblast to erythrocyte
246
Tc lymphocytes kill the organism against which they are programmed by
Damaging its membrane on contact
247
The stem cell factor that promotes the development of leukocytes is secreted by
Reticular cells of bone marrow
248
A promastocyte is
The immediate precursor of a mast cell
249
The development of erythrocytes is promoted by a hormone secreted in the
Kidneys
250
NK cells kill cells that
Match their Fab
251
Fenestrae closed by thin diaphragms are found in the capillary endothelium in the
Digestive tract
252
In a heathy body, intravascular coagulation is prevented by _____ on the endothelial cells
Protein C/ protein S complex
253
The tunica media of an arteriole is
1 to 2 layers of smooth muscle
254
The tendency of a contracted smooth muscle cell to remain in its contracted state is called
The latch effect
255
A small group of skeletal muscle cells isolated by perimysium is a
Fascicle
256
The conversion of monocytes to osteoclasts is inhibited by
Estrogen
257
Small electric currents cause osteocytes to secrete
Prostaglandin E2
258
The principle defense against blood parasites is the
Macrophages of the spleen
259
Linear acceleration in the vertical plane is detected by the
Hair cells of the saccule
260
The joint between the incus and the stapes is a
Diarthrosis
261
The pinnacle of the ear consists of _____ covered by skin
Elastic cartilage
262
The focal of the retina contains only
Cones
263
Complete dark adaptation of a rod takes about
45 minutes
264
For a human to focus on an object close at hand the lens must
Thicken
265
The elasticity of the lens capsule is provided by
Collagen IV
266
Langerhans cells are antigen-presenting cells in the
Epithelium of the tonsils
267
How many afferent lymphatics does the spleen have?
None
268
Most of the stroma of a lymph node is
Reticular connective tissue
269
The antigen specificity of a thymocyte is determined by
Multiple crossovers within the T-cell receptor genes
270
T-lymphocyte development is absolutely dependent on
Thymic humoral factors
271
A megakaryocte dies
After producing one cohort of platelets
272
Neutrophils kill phagocytosed bacteria with the _____ in their lysosomes
Hypochlorous acid
273
Hemangioblasts can develop into
Endothelial cells or HSC
274
The smooth muscle cells in the media of elastic arteries secrete
Collagen fibers and sheets of elastin
275
Atrial cardiomyocytes release atrial natriuretic factor in response to
Stretching
276
Troponin shrinks when exposed to
Calcium ions
277
Depolarization of the T-tubule membranes of a skeletal muscle fiber rearranges the _____ which opens the ryanodyne receptor so that Ca++ can enter the cytosol
Dihydropyridine receptor
278
The perikarya of primary sensory neurons for touch are found in
Dorsal root ganglia
279
The astrocyte “feet” around brain capillaries retract to create a perivascular space during
Sleep
280
Cut axons in the spinal cord do not regenerate because _____ inhibit growth
Glycoproteins in the myelin made by oligodendrocytes
281
Almost all of the capillaries in the brain are
Tight capillaries
282
NG2 cells often become
Oligodendrocytes
283
It is exceedingly rare for an axon hillock to contain
Ribosomes
284
A bare majority of the cells in the brain are
Astrocytes
285
The cytoplasm of a normoblast is acidophilic because it contains a great deal of
Hemoglobin
286
The most important refracting media of the eye are the lens and the
Aqueous humor
287
Myopia is the result of the eye for being _____ for its optical system
Too long
288
Cones are absent from both
- The margin of the visual retina
| - Blind spot
289
The choroid lies between the
Retina and sclera
290
Epineurium is made by
Fibroblasts
291
A tripartite synapse is the junction of processes of 2 neurons and one
Astrocyte
292
The ciliary muscle of the eye is
Multi-unit smooth muscle
293
Single unit smooth muscle has very few
Nerve endings
294
The atrial cardiac muscle cells secrete atrial natriuretic factor primarily in response to
Distension
295
A normal human blood platelet is _____ in diameter
4 micrometers
296
The immediate precursor of the monoblast is the same as the immediate precursor of the
Neutrophil myeloblast
297
The only cells that present unprocessed antigens are the
Follicular dendritic cells of a lymph node
298
The only place in the body where whole blood leaves the blood vessels is the
Spleen
299
Most of the lymphocytes that migrate from the blood to a lymph node do so by
Diapedesis through the endothelium of a high endothelial venule
300
If the eyeball is too long for its lens then the patient is
Myopic
301
The cells of Descemet’s endothelium use sodium/potassium ATPase to
Partially dehydrate the cornea
302
The role of endothelium is to
Regulate local blood pressure and prevent coagulation
303
The lysosomes of neutrophils produce both
Hypochlorous acid and superoxide ions
304
The state that immediately follows basophilic erythroblast is
Polychromatophilic erythroblast
305
If an early B-lymphoblast (pre-pre-B-lymphocyte) makes contact with an antigen against one of its intracellular antibodies it
Reshuffles the gene for the Fab segment of that antibody
306
Thymic stromal lymphopoietin is secreted by
Hassal’s corpuscles (ERC-VI)
307
The thymus _____ with increasing age
Involutes
308
The follicular dendritic cells of lymph nodes are unique in that they present
Unprocessed antigens
309
Prolonged exposure to loud noise is most damaging to high frequency hearing because
High frequencies are heard closest to the oval window
310
The organ of Corti receives some protection from loud noises because
The stapedius and tensor tympani reflexively contract
311
High frequency hearing takes place
Near the vestibule
312
The fluid around the stereocilia of the hair cells of a semicircular canal is usually called
Endolymph
313
The scale vestibuli is separated from the cochlear duct by the _____ membrane
Basilar
314
Otoliths are found in the
Saccule
315
Aqueous humor is secreted by the
Ciliary processes
316
Most smooth muscle fibers are
Single cells linked to their neighbors by gap junctions
317
The I-band of smooth muscle is
Nonexistent
318
The H band of skeletal muscle contains
Myosin
319
The volume of sacroplasmic reticulum per mm3 of ventricular cardiac muscle is _____ the volume of sacroplasmic reticulum per mm3 of skeletal muscle
More than
320
Atrial muscle fibers are unusual in that they have no
T-tubules
321
The ciliary muscle of the eye is
Multi-unit smooth muscle
322
The elastic arteries of the human body include
- Renal
- Common carotid
- Femoral
(All the above)
323
Lymph is propelled through the larger lymphatic vessels by
Contraction and relaxation of the surrounding skeletal muscle fibers
324
The epithelial reticular cells of the thymus secrete
Polypeptide hormones
325
The majority of cells in the brain are
Astrocytes
326
The tunica media of an arteriole is
1 to 4 layers of smooth muscle
327
A smooth muscle fiber contains
A single dense nucleus with condensed chromatin
328
White blood cells enter areolar connective tissue by way of
Endothelial cell junctions
329
The granules of neutrophils are _____ the granules of eosinophils
Smaller than
330
Calcium ions shrink _____ to allow skeletal muscle to contract
Troponin
331
The inferior vena cava has
Longitudinal smooth muscle in the adventitia
332
Moving through a small capillary, an erythrocyte is
Conical
333
Tissue plasminogen activator is secreted by
Endothelial cells
334
The unique feature of a tonsil is the presence of
Crypts
335
The macrophages of the spleen destroy
Infected red blood cells
336
The fluid around the stereocilia of the hair cells of a semicircular canal is usually called
Endolymph
337
Humans have _____ semicircular canals in each ear
3
338
Prolonged exposure to loud noise damages hearing
Most in the high frequency range
339
The lens gets its nutrients from the
Aqueous humor
340
A neutrophil attacks bacteria that
Match its lipopolysaccharide receptors
