phys exam 3 Flashcards
(371 cards)
1
Q
longitudinal vibrations of gas particles in an external medium
A
sound waves
2
Q
frequency of a sound wave is determined by
A
difference between two maximal pressure phases
3
Q
outer ear is composed of
A
ear pinna and ear canal
4
Q
the outer ear funnels sound toward the
A
tympanic membrane
5
Q
the middle ear is connected to the nasopharynx by
A
eustachian tube
6
Q
three ossicles of the middle ear
A
malleus
incus
stapes
7
Q
which ossicles are attached to skeletal muscle to regulate vibration
A
malleus
stapes
8
Q
skeletal muscle attached to the malleus
A
tensor tympani muscle
9
Q
skeletal muscle attached to the stapes
A
stapedius muscle
10
Q
which cranial nerve communicates with the stapedius muscle
A
motor nucleus VII (facial nerve)
11
Q
which cranial nerve communicated with the tensor tympani muscle
A
motor nucleus V (trigeminal nerve)
12
Q
3 semicircular canals
A
scala vestibuli (dorsal)
scala media
scala tympani (ventral)
13
Q
scala vestibuli and scala tympani contain
A
perilymph; high [Na+]
14
Q
scala media contains
A
endolymph; high [K+]
15
Q
functional unit of the ear
A
organ of corti
16
Q
organ of corti is located
A
on top of basilar membrane
17
Q
on top of the organ of corti is the ____ which contains mechanosensitive K+ channels
A
tectorial membrane
18
Q
auditory pathway - 1 - hair cell sends signal to
A
spinal ganglion (PNS)
19
Q
auditory pathway - 2 - spinal ganglion sends signal to ___ via ___
A
cochlear nuclei (medulla) via
cranial nerve VIII (vestibulocochlear)
20
Q
auditory pathway - 3 - cochlear nuclei sends signal to ____ via ____
A
superior olivary complex (medulla-pons) via
trapezoid body (some fibers will travel from R to L or L to R)
21
Q
auditory pathway - 4 - superior olivary complex sends signal to ____ via ____
A
inferior colliculus (mesencephalon) via
lateral lemniscus
22
Q
auditory pathway - 5 - inferior colliculus sends signal to ____ via ____
A
medial geniculate nucleus (diencephalon) via
brachium of the inferior colliculus
23
Q
auditory pathway - 6 - medial geniculate nucleus sends signal to ___ via ___
A
auditory cortex (telencephalon) via
auditory radiations
24
Q
the anterior and posterior chambers of the eye contain ____ which provides ___
A
aqueous humor
nutrients for the cornea and lens
25
the lens is suspended by ligaments called ____ which are attached to ___
zonular fibers
ciliary body (ciliary muscles)
26
the vitreous humor of the eye is composed of
gelatinous fluid and phagocytic cells
27
what is the function of tear fluid
lubricates the eye
prevents frost damage of the cornea
moistens the nasal cavity
combat bacteria
28
tears are produced by
lacrimal gland
29
reflective patch in the eye for nocturnal seeing
tapetum lucidum
30
changes to eye when looking far away
ciliary muscle relaxes
inc tension of suspensory ligaments
lens flattened
31
changes to eye when looking nearby
ciliary muscle contraction
dec tension of suspensory ligaments
lens rounded
32
a spherical lens increases
refractive power - increases focus
33
cells of the retina (outside to inside)
retinal pigmented cells
photoreceptors
horizontal cells
bipolar cells
amacrine cells
ganglion cells
34
retinal cell for nourishment and protection of photoreceptors
retinal pigmented cells
35
rods and cones
photoreceptors
36
retinal cell for lateral interactions among photoreceptors and bipolar cells
horizontal cells
37
retinal cell for connection photoreceptors with ganglion cells
bipolar cells
38
retinal cell for lateral interactions among bipolar cells and ganglion cells
amacrine cells
39
axons that form the optic nerve
ganglion cells
40
part of eye that contains the optic disc and tepetum
fundus
41
characteristics of the rod system
most sensitive to light
night vision/low light
low acuity
achromatic
peripheral retina
42
characteristics of the cone system
less sensitive to light
day vision
high acuity
color vision
central retina (fovea)
43
the visual photopigments contained in the discs of the outer segments
opsin (G protein)
retinal (aldehyde of vit. A; retinol)
44
in darkness, ___ binds to opsin; together produce cGMP
11-cis-retinal
45
production of cGMP in the disc causes
Na channels to open, Na in, cell depolarized, glutamate released
46
when stimulated by light, Na channels ___
hyperpolarize
47
what configuration change does light cause
changes 11-cis-retinal to all-trans-retinal; detaches from opsonin
48
in the presence of light, opsin binds to the G protein ___ which activates ___ to hydrolyze cGMP
transducin
phosphodiesterase (PDE)
49
in the presence of light, the hydrolyzed cGMP causes a reduction in cGMP which leads to ___, ____ and ___
Na channels closed
hyperpolarization
less glutamate release
50
carnivorous species have frontal positioned eyes - how does this affect their vision
restricted monocular lateral field
large central binocular field
51
herbivorous species have lateral positioned eyes - how does this affect their vision
wide monocular lateral field
very narrow central binocular vision
52
where is the lateral geniculate nucleus located
thalamus
53
where is the primary visual cortex located
occipital lobe
54
the reticulo-geniculo-striate pathway goes to the cerebral cortex and crosses at the
optic chiasm
55
direction of travel for vision at the reticulo-geniculo-striate pathway
R visual field projects to the L nasal retina; axons travel to the L lateral geniculate nucleus and to the L primary visual cortex
(vice versa for L visual field)
56
cranial nerves involved in the pupillary light reflex and consensual response
optic nerve
oculomotor nerve
57
the circular muscular fibers constrict the pupil in strong light; how are they innervated
parasympathetically
58
the radial muscles dilate the pupil in low light; how are they innervated
sympathetically
59
what is the consensual response
pupillary light reflex in both eyes, even if one is uncovered
60
olfactory section of the brain; size is varied in different species
rhinencephalon
61
how does air pass through the nasal cavity when the dog is sniffing
air passes above the heat exchanger - reaches the olfactory epithelium directly
62
olfactory cells are (primary or secondary) receptor cells
primary
63
odor receptors are covered by
membrane of the cilia
64
for signal amplification, several unmyelinated axons of olfactory cells synpase with a ____
mitral cell in the glomerulus (olfactory bulb)
65
odor molecules are dissolved in
gas or water
66
what kind of receptor are odorant receptors
GPCR
67
olfactory epithelium sends signal to
olfactory bulb
68
olfactory bulb sends signal to
olfactory cortex
69
components of olfactory cortex
anterior olfactory nucleus
piriform cortex
amygdala
entorhinal cortex
70
thalamus receives olfactory signals from
frontal cortex
piriform cortex
caudate nucleus
anterior olfactory nucleus
amygdala
71
thalamus sends olfactory signal to
frontal cortex
72
entorhinal cortex sends olfactory signal to
hippocampus
73
create and store olfactory gestalts
anterior olfactory nucleus
74
behavioral, cognitive and contextual information
piriform cortex
75
emotional processing of olfactory information
amygdala
76
working memory
entorhinal cortex
77
conscious olfactory experience
frontal cortex
78
olfactory stimuli action
thalamus
79
reward system
caudate nucleus
80
odor threshold; reception of odor
hippocampus
81
paired, cylindrical organ located ventrally and medially in the anterior portion of the nasal septum; connected to the oral cavity; function to recognize odor molecules dissolved in fluids
vomeronasal organ
82
function of flehmen response
direct fluids into the vomeronasal organ
83
taste receptor cells are (primary or secondary)
secondary receptor cells
84
location of taste buds in ruminants
mostly basis of the tongue
85
location of taste buds in dogs
mostly in the tip
86
what species are taste buds poorly developed
birds
87
receptors for salty and sour are
ionotropic
88
receptors for sweet, bitter and umami are
metabotropic
89
what kind of channels does capsaicin bind to
heat sensitive channels
90
which cranial nerves synapse at the first order neuron for gustation
cranial nerve VII (facial)
cranial nerve IX (glossopharyngeal)
91
afferent fibers in the facial and glossopharyngeal nerves synapse with neurons in which tract
solitariothalamic tract
92
where do neurons in the solitary tract go to
thalamus then cerebral cortex
93
fluid phase of blood that contains non-cellular components; including coagulation factors
plasma
94
what components of plasma produce oncotic pressure
proteins incl. albumin, globulins, fibrinogen
95
amount of RBCs in the blood
hematocrit
96
differences in hematocrit values can be due to
differences in the number of size of RBCs
nutrition, physical activity, metabolic rate
altitude
97
what causes inc hematocrit during physical activity
increased sympathetic nervous system activity; erythrocytes are mobilized from the spleen and cardiovascular system
98
function of RBCs
transport O2 from the lungs to the body Hb; remove CO2 from tissues
99
what is essential to RBC function
number, shape and Hb concentration
100
how does Hb bind oxygen
reversibly without changing the valence
101
each of Hb's 4 subunits contains
globular peptide chain (alpha or beta)
heme group that contains iron
102
where does erythropoiesis take place
liver and spleen - fetal
red marrow long bones - birth to adolescence
red marrow flat bones - after adolescence
103
in the bone marrow, all blood cells are derived from
pluripotent stem cells
104
what type of cell will be seen in high amounts in systemic blood in a patient with regenerative anemia
reticulocytes
105
erythropoiesis requires
iron
vitamin B12 and folic acid
erythropoietin
106
iron is necessary for
Hb synthesis
107
vitamin B12 and folic acid are needed for
DNA synthesis
108
where is erythropoietin produced; what upregulates its production
produced in the kidney
upregulated by low oxygen tension in the tissues
109
as erythrocytes age their membranes becomes less flexible and they are more easily damaged; these damaged cells are removed by ____; this removal takes place in ____
macrophages;
spleen, liver, bone marrow
110
what happens to peptides released from Hb of damaged erythrocytes
recycled for protein synthesis
111
what happens to the heme groups released from Hb of damaged erythrocytes
converted into bilirubin that will go into bile
112
what happens to iron released from Hb of damaged erythrocytes
transported to the bone marrow to form new heme groups
113
lifespan of erythrocytes
90-140 days
114
three general causes of anemia
blood loss - hemorrhage
RBC destruction - hemolysis
dec RBC production
115
clinical symptoms of anemia are caused by
reduced amount of Hb and decreased oxygen transport capacity
116
type of anemia with an increased number of circulating reticulocytes, indicating inc bone marrow erythropoiesis
regenerative anemia
117
regenerative anemia may be caused by ___ and ___
hemorrhage and hemolysis
118
type of anemia where reticulocytes are low and there is no increased erythropoiesis
nonregenerative anemia
119
nonregenerative anemia may be caused by
impaired bone marrow function and extramarrow diseases
120
some intrinsic defects that lead to hemolysis include
Hb defects
sickle cell disease
membrane deformation
enzyme deficiencies
121
some extrinsic defects that lead to hemolysis include
chemicals that cause methimaglobin formation, denaturation of Hb
parasitism
immune mediated - hemolytic anemia of the newborn
122
some causes of impaired bone marrow function include
FeLV
chemotherapeutics
congenital disorders
123
some causes of extramarrow diseases
chronic renal failure
liver disease
B12 deficiency
iron deficiency
124
iron deficiency can cause ___ in piglets
microcytic hypochromic anemia
(small cells, low Hb)
125
transports fluid, proteins, fat
transports pathogens and Ags from tissues into lymphatic tissues
lymphatic system
126
where does lymph accumulate;
where do lymph vessels carry lymph
accumulates in tissues - interstitium
brought to thoracic duct and into blood
127
soluble components of innate immunity
interferon
peptides
complement
128
cell mediated components of innate immunity
macrophages
granulocytes
dendritic cells
129
soluble components of adaptive immunity
immunoglobulins from B cells
130
3 components of hemostasis after injury
constriction of injured blood vessel
formation of platelet plug
coagulation
131
when platelets adhere to collagen fibers in the wall of an injured vessel, they release ___ and ____ to increase platelet adhesiveness and form the platelet plug
ADP
TXA2 (thromboxane A2)
132
platelet adhesiveness is decreased by
prostacyclin
nitric oxide (NO)
133
how long does it take completely seal off a broken vessel
30-60 min
134
blood coagulation requires
Ca
135
intrinsic activation of the coagulation cascade is activated by
collagen fibers or other surfaces
136
extrinsic activation of the coagulation cascade is activated by
tissue thromboplastin factor III that is released from surrounding tissues after tissue damage
137
what coagulation factor is activated by collagen
XII
138
coagulation factor XII activates
factor XI
139
coagulation factor XI activates
factor IX
140
coagulation factor X is activated by
factor IX
factor VII
141
thrombin activates; thrombin can have a positive feedback effect on these coagulation factors
factor XI
factor VIII
factor V
142
thrombin is converted from
prothrombin by factor X
143
fibrinogen is converted into
fibrin
144
which factor is the limiting step in the coagulation cascade
factor X
145
slow process that begins immediately after clot formation
fibrinolysis
146
an active proteolytic enzyme that slowly dissolves a clot
plasmin
147
coagulation factors are produced in
liver
148
hemophilia
congenital deficiency in coagulation factors VIII (hemophilia A) or IX (hemophilia B)
149
the liver requires ___ for carboxylation and synthesis of coagulation factors
vitamin K
150
warfarin in rat poison inhibits the enzyme ____, which is necessary for activating vitamin K
vitamin K epoxide reductase
151
acetylsalicylic acid, aspirin, inhibits the formation of platelet plugs by inhibiting the synthesis of ____
thromboxane A2
152
many anticoagulants like EDTA or citrate are
Ca chelators
153
blood group A antigens have an additonal
GalNAc group
154
blood group B antigens have an additional
Gal group
155
AB0 blood group antigens are
glycosphingolipids
156
what occurs after an incompatible blood transfusion
agglutination and hemolysis
157
individuals with Rh- blood generate Ab against Rh+ patients; Rh- mothers can pass Ab against their Rh+ fetus causing
hemolytic anemia in the baby
158
cross-matching blood is done using
donor blood
recipient serum
159
neonatal isoerthyrolysis (hemolytic disease in the newborn) can develop in Aa+ foals of Aa- mothers after the foal consumes the colostrum which contains
IgG antibodies against the foal's Aa+ RBCs
160
valve from RA to RV
tricuspid valve
161
valve from RV to pulmonary artery
pulmonary valve
162
valve from LA to LV
mitral valve
163
valve from LV to aorta
aortic valve
164
LV ventricle contracts and ejects blood into the aorta, distending the aorta and raising aortic BP to its peak value called
systolic aortic pressure
165
outflow of blood from aorta between ejections; decreases to minimal value of aortic BP reached just before the next cardiac ejection called
diastolic aortic pressure
166
average value of pulsatile BP in the aorta; represents a potential energy for driving blood through circulation
mean aortic pressure
167
volume of blood pumped each minute by one ventricle; ___ for LV and RV are about equal
cardiac output
168
pressure difference between mean aortic pressure and mean venae cavae pressure
systemic perfusion pressure
- typically 95 mm Hg
169
pressure difference between mean pulmonary artery BP and mean pressure in pulmonary veins
pulmonary perfusion pressure
- typically 8 mm Hg
170
what type of circulation is high pressure high resistance
systemic
171
what type of circulation is low pressure low resistance
pulmonary
172
what type of vessels are most of a dog's blood stored in
veins/venules
173
what kind of vessel is most abundant, greatest cross-section are and slowest velocity
capillaries
174
arrangement of two systemic capillary beds in a series
portal system
175
role of splanchnic portal system
detoxification
176
role of renal portal system
generation of urine; waste removal
177
role of hypothalamic-hypophyseal portal system
regulation of hormone secretion in the anterior pituitary
178
common proteins found in plasma
globulin
albumin
fibrinogen
179
main electrolytes in plasma
Na+
Cl-
HCO3-
180
gases found in plasma
O2
CO2
N2
181
mean quantity of Hb in each RBC
mean corpuscular hemoglobin (MCH)
182
mean quantity of Hb in each deciliter of packed RBCs; hemoglobin/hematocrit
mean corpuscular hemoglobin concentration (MCHC)
183
only a small portion of CO2 is dissolved in the blood, in what other form is it found in the plasma
hydrated to form HCO3-
combines with Hb or plasma proteins to form carbamino compounds
184
main nutrients in plasma
glucose
amino acids
lipids
some vitamins
185
waste products found in plasma
CO2
urea
creatinine
uric acid
bilirubin
186
common hormones found in plasma
insulin
epinephrine
thyroxine
187
normal canine hematocrit range
35-57%
188
normal RBC range in dogs
5000-7900 x 10^3/uL
189
normal WBC range in dogs
5-14 x 10^3/uL
190
normal platelet range in dogs
210-620 x 10^3/uL
191
normal blood Hb range in dogs
12-19 g/dL
192
normal MCH range in dogs
21-26 pg
193
normal MCHC range in dogs
32-36 g/dL
194
difference between plasma and serum
serum contains no clotting factors; no anti-coagulant prior to spinning down
195
abnormally high hematocrit; increases blood viscosity; makes it difficult for the heart to pump and can lead to heart failure
polycythemia
196
anemia can be caused by low hematocrit or low MCH and/or MCHC; how can anemia lead to heart failure
cardiac output must be increased above normal to deliver the normal amount of oxygen to the tissues
197
by what transport method does blood move through the heart and blood vessels
bulk flow
198
sources of energy for bulk flow include
perfusion pressure
transmural pressure
199
pressure difference that causes blood to flow through blood vessels;
Pinlet - Poutlet
perfusion pressure
200
pressure difference between the BP inside a blood vessel and the fluid pressure in the tissue immediately outside the vessel;
Pinside-Poutside
transmural pressure
201
major mode of transport that occurs at capillaries; movement from high to low concentration
diffusion
202
specialized cardiac muscle cells that can spontaneously depolarize toward the threshold for APs; source of electrical activity of the heart
pacemaker cells
203
RMP of a polarized cardiac cell
-60 to -80mV
204
each normal heartbeat is initiated by a spontaneous AP generated by pacemaker cells in the
SA node
205
ventricular rate from SA node cells in a resting dog
80-90 beats/min
206
emergency pacemaker for ventricles; usually overridden by SA node; created AV delay so the atria and ventricles do not contract at the same time
AV node
207
how does the conduction velocity and refractory period of the AV node compare to the SA node
slower velocity; longer refractory period
208
part of heart that contributes to nearly synchronous contraction of all fibers in both ventricles
purkinje fibers
209
after the ventricles contract, what occurs
entire heart relaxes and fills
210
the pause between atrial contraction and ventricular contraction is caused by
slow propagation of AP through the AV node
211
when a region of ischemic cardiac muscle develops the abnormal twin properties of slow conduction of APs and only able to conduct in one direction
ectopic pacemakers (also called reentrant APs)
212
passage of an AP around and around a nonconducting center; can cause reentrant arrhytmia
circus movement
213
the pacemaker potential is caused by spontaneous changes in what 3 ion channels
Na+
Ca2+
K+
214
generation of pacemaker potential sequence from RMP
K+ channels close; Na+ channels open
slow influx of Na+ until -40mV
Ca2+ channels open; Ca2+ in; depolarization
K+ channels open; K+ out; repolarization
215
which channel is primarily responsible for AP generation in a pacemaker cell
Ca2+
216
RMP is formed by
Na+ K+ pump - 3 Na out, 2 K in
leaking K+ channels
closed Ca channels
217
cardiac AP formation phase 0
cell depolarized to threshold voltage for opening voltage gated Na channels; causes rapid depolarization
218
cardiac AP formation phase 1
Na channels inactivate, Na permeability decreases; membrane begins to repolarize
219
cardiac AP formation phase 2
some gated K channels close, K permeability decreases; many gated Ca channels (L-type Ca channels) open; Ca permeability increases; prolonged plateau of depolarization
220
Ca entering a cardiac cell during an AP triggers release of additional Ca from ___, initiating cardiac contraction
sarcoplasmic reticulum
221
cardiac AP formation phase 3
K channels reopen and Ca channels close; cell repolarizes
222
cardiac AP formation phase 4
cell returns to stable negative resting potential
223
cardiac muscle cells form a ____ in which specialized gap junctions allow ionic currents to flow quickly into neighboring cells
functional syncytium
224
what is the purpose of a long refractory period between cardiac muscle contractions
allows heart to completely relax and refill before the next contraction
225
atrial cells have (shorter or longer) APs and refractory periods than ventricular cells
shorter
226
norepinephrine and epinephrine are secreted by
sympathetic nerve or adrenal medullar glands
227
where does norepi and epi bind on cardiac pacemaker cells
B-adrenergic receptors
228
effect of norepinephrine and epinephrine of pacemaker cells
elevate HR
229
acetylcholine is secreted by
parasympathetic nerves
230
where does Ach bind on pacemaker cells
muscarinic cholinergic receptors
231
effect of acetylcholine on pacemaker cells
decrease HR
232
intrinsic HR of a normal large dog
140 bpm
233
effect of norepinephrine and epinephrine on all cardiac muscle cells
taller more positive plateau APs
shorter duration APs
quicker, stronger, shorter duration contractions
234
how does norepinephrine and epinephrine contribute to a taller and more positive plateau AP
increases the number of L type Ca channels that open during the plateau phase
235
how does norepinephrine and epinephrine contribute to shorter duration APs
the more positive plateau opens K channels sooner, shortening the AP and speeding up repolarization
236
how does norepinephrine and epinephrine contribute to quicker, stronger and shorter contractions
more Ca channels opened increases entry of extracellular Ca - quicker and stronger
speeding up Ca pumped back out of cell - shorter duration
237
how does acetylcholine affect atrial cells
exerts strong anti-sympathetic influences
238
how does acetylcholine affect ventricular muscle cells
indirect effect
inhibits release of norpeinephrine
weakens effects of sympathetic activation
239
cardiac arrhythmias caused by pacemaker cell problems
sick sinus syndrome
tachyarrhythmias
240
extreme form of sick sinus syndrome
sinus arrest
SA node fails to form APs - AV node keeps ventricles beating at very slow rate
241
less extreme form of sick sinus syndrome
sluggish depolarization of SA node
low intrinsic HR
low HR at rest - bradycardia
insufficient inc in HR during exercise
242
treatments of sick sinus syndrome
cholinergic muscarinic antagonist drugs (ex. atropine)
B-adrenergic agonist drugs (ex. isoproterenol)
artificial cardiac pacemaker
243
tachycardia caused by abnormally rapid depolarization of SA node pacemaker cells
sinus tachycardia
244
tachycardia originating from an ectopic pacemaker in the atria; common in boxers and wolfhounds
atrial tachycardia
245
extremely rapid atrial tachycardia
atrial flutter
246
rapid atrial contractions that lose synchrony - no blood gets pumped; SA node is still working;
common in horses and dobermans
atrial fibrillation
247
tachycardia originating from ectopic pacemakers within AV node or first part of AV bundle
junctional tachycardia
248
collective term encompassing sinus, atrial and junctional tachycardia
supraventricular tachycardia
249
tachycardia originating from ectopic pacemakers within the ventricles; ventricles do not relax long enough for adequate filling; exacerbated by inappropriately timed atrial contractions
ventricular tachycardia
250
each tiny region of the ventricular wall contracts and relaxes at random in response to random and continuous APs; can cause sudden cardiac death
ventricular fibrillation
251
complete block of AV node
third degree AV node block
252
AV node transmits some atrial APs but not all of them; can be created or exaggerated by strong parasympathetic activity due to increased refractory period of AV node cells
second degree AV node block
253
fading and eventual stoppage of a cardiac AP in a slowly conducting region; often involved in 2nd and 3rd degree AV node block
decremental conduction
254
every atrial AP is transmitted to the ventricles; AP propagates more slowly and HR is slower
first degree AV node block
255
AV node block can be caused by
cardiac trauma
toxins
infections
ischemia
congenital defects
cardiac fibrosis
inadvertent damage of AV node during surgical repair of ventricular septal defect
256
treatment of AV node block
muscarinic cholinergic antagonist
B-adrenergic receptor agonists
artificial pacemaker applied to ventricles
257
types of antiarrhythmic drugs
local anesthetics
calcium channel blockers
cardiac glycosides
beta-adrenergic antagonists
258
how do local anesthetics work
bind to some voltage gated Na channels
counteracts membrane depolarization and AP formation
259
how do calcium channel blockers work
bind to some L-type Ca channels and prevent them from opening
lowers plateau
lengthens AP - slower opening of K channels
decreases strength of contractions
260
how do cardiac glycosides work
inhibiting Na K pump
allow more Ca than normal to accumulate inside, resulting in stronger but slower contractions
inc in parasympathetic tone
261
how do beta-adrenergic antagonists work
bind to some of B-adrenergic receptors
prevent activation by norepinephrine
dec HR
lengthen refractory period
slow conduction of AP
reverse sympathetic induced increases in contractility
262
ex of local anesthetics
quinidine
lidocaine
procaine
263
ex of calcium channel blockers
verapamil
diltiazem
nifedipine
264
ex of cardiac glycosides
digitalis
265
ex of beta-adrenergic antagonists
propranolol
266
where is lead I recorded; what is it compared with
recorded in LF (+)
compared with RF (-)
267
where is lead II recorded; what is it compared with
recorded in LH (+)
compared with RF (-)
268
where is lead III recorded; what is it compared with
recorded in LH (+)
compared with LF (-)
269
where does the aVR lead measure the voltage from; what is it compared with
voltage from the RF
compared with average voltage from other two limb electrodes
270
where does the aVL lead measure the voltage from; what is it compared with
voltage from LF
compared with average voltage from other two limb electrodes
271
where does the aVF measure the voltage from; what is it compared with
voltage from LH
compared with average voltage from other two limb electrodes
272
P wave corresponds to
atrial depolarization
273
how does the voltage compare between the RF and LF during atrial depolarization; why
LF is positive
because RA depolarizes and becomes negative first
274
what cannot be detected by ECG
atrial repolarization
275
Q wave corresponds to
interventricular septum depolarization that spreads from L to R
276
how does the voltage compare between the LF and RF during interventricular septum depolarization
LF slightly negative compared to RF
277
R wave corresponds to
ventricular depolarization
outward spreading AP in both ventricles
278
S wave corresponds to
depolarization of ventricular base
end of depolarization in both ventricles
279
how does the voltage compare between LF and RF during depolarization of ventricular base
LF returns to zero then becomes slightly negative for a few ms
280
T wave corresponds to
ventricular repolarization of both ventricles
281
what makes a positive T wave
repolarization spreads inward through both ventricles;
outermost portion of ventricular wall repolarizes first
282
what makes a negative T wave
ventricular repolarization proceeds from in to out
283
time between the start of atrial depolarization and start of ventricular depolarization
PR interval;
ex. 0.13 s in a large resting dog
284
time it takes for the ventricles to depolarize once the AP emerges from the AV node and AV bundle
QRS complex;
ex. <0.1 s in a large resting dog
285
time from beginning of ventricular depolarization to end of ventricular repolarization; duration of an AP in ventricular tissue
QT interval;
ex. 0.2 s in a large resting dog
286
time between atrial depolarizations; can be used to calculate the atrial rate (# of atrial contractions/min)
PP interval
287
time between ventricular depolarization; can be used to calculate the ventricular rate
RR interval
288
what is the standard vertical calibration on an ECG
10 mm = 1 mV
289
different chart speeds of an ECG
25 mm/s: 5 mm = 0.2s per major division
50 mm/s: 5mm = 0.1s per major division
290
ECG vary more among (small or large) animals
large
291
ECG abnormality: polarity of QRS from lead I is negative - suggesting mass of RV has increased; high voltages of QRS from lead II and III; pronounced negative components in QRS from leads II and III
right ventricular hypertrophy
292
ECG abnormality: abnormally low ECG voltage
accumulation of fluid within the pericardium
293
ECG abnormality: ST segment elevation due to TP segment depression - inability of ventricular muscle cells to maintain a normal negative RMP
ischemic or infarcted area in the inferior part of the ventricle
294
ECG abnormality: abnormal shape and long duration of QRS; premature depolarization originated from an ectopic site; predominant positive voltage in lead I
premature ventricular contractions (PVCs)
295
ECG abnormality: fast resting HR; each QRS is preceded by a positive P wave followed by a positive overlapping T wave; rapid HR initiated by SA node pacemakers
sinus tachycardia
296
ECG abnormality: slow resting HR; normal P, QRS and T waves; slow and irregular
sinus bradycardia
297
ECG abnormality: PR intervals are abnormally long - indicates abnormally slow conduction of AP through the AV node and AV bundle
first degree AV node block
298
ECG abnormality: some P waves are not followed by QRS-T waves - indicates some atrial depolarization is conducted through AV node
second degree AV node block
299
ECG abnormality: QRS-T waves present but not preceded by P waves - indicates the QRS-T waves were caused by auxiliary pacemakers
third degree AV node block
300
ECG abnormality: abnormally shaped ventricular complexes of faster and higher voltage - indicating an ectopic ventricular pacemaker; frequently will degenerate into ventricular fibrillation
ventricular tachycardia
301
ECG abnormality: large, irregular voltage fluctuations with no discernible pattern
ventricular fibrillation
302
ECG abnormality: random, high frequency, low amplitude voltage fluctuations (f waves); QRS-T normal in shape but occur irregularly; atria do not contract synchronously or effectively
atrial fibrillation
303
atrial systole
contraction
304
diastole
relaxation
305
when do atria contract
at the end of ventricular filling
306
what occurs during ventricular systole
AV valves (mitral and tricuspid) close
isovolumetric contraction - aortic and pulmonary valves open
rapid and reduced ejection - aortic and pulmonary valves close
307
during ventricular systole, when do the aortic and pulmonary valves open
when ventricular pressures exceed the pressure in aorta and pulmonary artery
308
during ventricular systole, when do the aortic and pulmonary valves close
at the end of ejection due to the back flow of blood
309
what occurs during ventricular diastole
isovolumetric relaxation - mitral valve and tricuspid valves open
rapid and reduced ventricular filling (diastasis)
310
during ventricular diastole, when do the mitral and tricuspid valves open
when ventricular pressures fall below atrial pressures
311
how long does diastasis persist
until the SA node cells initiate another atrial AP
312
end diastolic volume
blood volume in each ventricle at the end of diastole
313
end systolic volume
remaining blood volume at the end of systole
314
stroke volume
volume of blood ejected from one ventricle in one beat
(end diastolic volume) - (end systolic volume)
315
ejection fraction
(stroke volume)/(end diastolic volume)
50-65% typical in resting dogs
316
cardiac output
total volume of blood pumped by one ventricle in one minute
stroke volume x HR
317
what factors affect the heart to eject blood
end diastolic ventricular volume
ventricular contractility
arterial BP
HR
318
increased end diastolic ventricular volume will cause
an inc in stroke volume
319
what is the result of stretching the ventricular muscle fibers during diastole
more calcium is released from the sarcoplasmic reticulum during contraction, increasing the force
320
pre load
ventricular pressure at the end of diastole
321
increased ventricular preload will cause
an inc in end diastolic ventricular volume and stroke volume
322
there are no valves between
veins and atria
323
central venous pressure (CVP)
pressure in cranial vena cava; equivalent to right ventricular preload
324
starling's law of the heart (heterometric autoregulation)
changes in preload cause corresponding changes in end diastolic ventricular volume and stroke volume
325
compliance
measure of the ease with which the ventricular walls stretch to accommodate incoming blood during diastole
change in volume / change in pressure
326
at what point do the ventricles become stiff and less compliant
at preloads higher than 10 mm Hg
327
what can cause ventricular walls to become stiffer
myocardial ischemia
certain cardiac diseases
advancing age
328
what could cause edema to develop in tissues upstream from the stiff ventricle
elevated preload causing elevated atrial and venous pressure
329
filling time
length of time available for ventricular filling during diastole
330
what is the main determinant of diastolic filling time
heart rate
331
ventricular contractility is increased by the release of ____, which activate B-adrenergic receptors on ventricular muscle cells
epinephrine and norepinephrine
332
what kind of drugs increase ventricular contractility
B-adrenergic agonists
cardiac glycosides
333
how do cardiac glycosides increase ventricular contractility
increase cytosolic Ca concentration during an AP
334
ventricular contractility is decreased by
B-adrenergic antagonists (like Ca channel blocking drugs)
barbiturates, opioids and some general anesthetics
335
hallmark of myocardial failure
decreased cardiac contractility
336
why does an increase in arterial BP impair ventricular ejection
the LV pressure during systole must exceed aortic pressure before ejection of blood from the ventricle can occur
337
cardiac afterload
pressure that a ventricle must generate in order to eject blood
338
increased HR reduces
diastolic filling time
339
what are some situations that cause an increase in HR but a decrease in cardiac output
artificial cardiac pacemakers
certain cardiac arrhythmias - ex paroxysmal atrial tachycardia
340
what situation causes an increase in HR and cardiac output
exercise
341
during vigorous exercise in a large dog, what cardiac changes will increase
stroke volume
ejection fraction
HR
cardiac output
342
during vigorous exercise in a large dog, what cardiac changes will decrease
ventricular end diastolic volume
ventricular end systolic volume
343
which sound is associated with the closure of the AV valves (mitral and tricuspid)
S1
344
which sound is associated with closure of the aortic valve on the left side and pulmonic valve on the right side; stronger sound than S1
S2
345
which sound is associated with the AV valve opening and a rush of blood in the ventricles causing the ventricular walls to vibrate; early diastole
S3
346
which sound occurs at the very end of diastole, as atrial systole causes a sudden rush of blood into the ventricles
S4
347
3 common types of heart murmurs
systolic
diastole
continuous
348
systolic heart murmurs can be cause by
insufficient or incompetent AV valve
ventricular septal defect (VSD)
aortic and pulmonic stenosis
349
large pressure difference between ventricle and atrium causes a rapid backward flow of blood through the partially closed valve (regurgitation)
AV valve insufficiency
350
hole in the interventricular septum
ventricular septal defect
351
aortic or pulmonary valve fails to open widely; common congenital defect in dogs
aortic and pulmonic stenosis
352
diastolic heart murmurs can be caused by
mitral or tricuspid stenosis
aortic or pulmonic insufficiency
353
tricuspid stenosis can be caused by
heartworm infestation in the right heart
354
aortic regurgitation is common in
horses
355
continuous murmurs can be caused by
patent ductus arteriosus (PDA)
arteriovenous fistulae
356
persistence of opening between aorta and pulmonary artery after birth; sometimes called "machinery murmur"
PDA
357
abnormal openings between peripheral arteries and veins, carries a turbulent flow during systole and diastole
arteriovenous fistulae
358
what are common consequences of cardiac defects
abnormally high or low blood flow to a region of the body
abnormally high or low BP in a region of the body
cardiac hypertrophy
359
effects of mitral regurgitation
LV hypertrophy
pulmonary edema
consequences more noticeable during exercise
360
effects of mitral stenosis
atrial fibrillation
pulmonary edema
361
effects of PDA
LV hypertrophy
RV hypertrophy
exercise intolerance
362
effect of aortic stenosis
exercise intolerance
363
effects of aortic regurgitation
LV hypertrophy
pulmonary edema may develop
364
effects of VSD
moderate LV hypertrophy
pronounced RV hypertrophy
possible pulmonary edema
probable exercise intolerance
365
effect of pulmonic stenosis
pronounced RV hypertrophy
366
minute work of a ventricle
(mean aortic/pulmonic pressure) x stroke volume x HR
367
stroke work
external work done by the ventricle in one cardiac cycle;
(mean aortic/pulmonic pressure) x stroke volume
368
cardiac internal work
wasted work appearing as heat;
~85% of metabolic energy consumed by the heart
369
which side of the heart has the greater cardiac energy consumption
left
370
hypertension causes
striking LV hypertrophy
371
why is excessive ventricular hypertrophy deleterious
- restricts opening of aortic or pulmonary valves, leading to stenosis
- coronary circulation may be unable to provide enough blood flow to meet the inc metabolic demand
- cellular growth factors that mediate hypertrophy also predispose the cardiac muscle to apoptosis
