Final Exam Flashcards
(516 cards)
1
Q
Action potentials of smooth muscle can be initiated by____, ____, or _____ simulation
A
neural, hormonal, mechanical
2
Q
Why is the upstroke slower in smooth muscle action potentials?
A
Because Ca2+ channels propagate the AP instead of Na+
3
Q
Why is the repolarization slower in smooth muscle action potentials?
A
Because Ca2+ channels inactivate slowly and there is a delayed activation of voltage gated K+ and in some cases Ca2+ - activated K+ channels
4
Q
Membrane potentials vary in smooth muscle: ____- ____ potentials fire action potentials when they reach threshold, while ____ potentials always depolarize to threshold
A
slow-wave, pacemaker
5
Q
Smooth muscle cells produce a ___ range of membrane potentials (Vm), and in some smooth muscle Vm oscillations can lead to ?
A
wide, tonic contractions in the absence of action potentials
6
Q
Action potentials usually do not occur in ______ smooth muscle
A
multiunit
7
Q
Autonomic neurons create a local depolarization that spreads _______ (graded fashion) throughout the muscle fibre triggering ____ entry
A
electrotonically, Ca2+
8
Q
Autonomic AP initiation (spikes or plateaus) and spontaneous AP (slow-wave or pacemaker) is considered ? whereas graded potentials are considered ?
A
single unit, multiunit
9
Q
Contraction due to electrical signaling is known as ?
A
electromechanical coupling
10
Q
Both _____ entry and _____ release of Ca2+ activate contraction and cytosolic [Ca2+]i is increased by __ different mechanisms
A
extracellular, intracellular, 3
11
Q
Both extracellular entry and intracellular release of Ca2+ activate contraction and cytosolic [Ca2+]i is increased by three different mechanisms:
1. Ca2+ entry through ___ gated channels or ____ gated ion channels
2. Ca2+ release from the __
3. Ca2+ entry through voltage-______ channels
A
- voltage, ligand
- SR
- independent
12
Q
? respond to graded stimulation or action potentials, both of which produce an influx of Ca2+ through voltage-gated L-type Ca2+ channels
A
Smooth muscle cells
13
Q
____ SR in smooth muscle than in skeletal and cardiac muscle
A
Less
14
Q
Ca2+ release from SR occurs via ___ -induced Ca2+ release and ___ pathway.
A
Ca2+, IP3
15
Q
IP3 pathway can cause contraction with minimal ______ and negligible extracellular Ca2+ ___
A
depolarization, influx
16
Q
What are the proper steps in GPCR-phospholipase C signal transduction:
1. PLC converts membrane phospholipids into diacylglycerol, which remains in the membrane, and IP3, which diffuses into the cytoplasm
2. Signal molecule activates receptor and associated G protein
3. DAG activates protein kinase C, which phosphorylates proteins
4. IP3 causes release of Ca2+ from organelles, creating a CA2+ signal
5. G protein activates phospholipase C, an amplifier enzyme
A
2, 5, 1, 3, 4
17
Q
Depletion of Ca2+ in the SR causes _____of store-operated channels which cause a ____ influx across the cell membrane. Allows [Ca2+]i to remain elevated and _____ SR.
A
activation, Ca2+, replenishes
18
Q
There is ____ on SR, while ____ proteins make up Ca2+ channel on cell membrane.
A
STIM1, Orai-1
19
Q
? occurs when chemical signals change muscle tension through signal transduction pathways with little or no change in membrane potential
A
Pharmacomechanical coupling
20
Q
Ca2+ release from SR via IP3 pathway and entry of Ca2+ via store operated channels are voltage independent and is known as ?
A
pharmacomechanical coupling
21
Q
____, _______ _______ and _____ can induce smooth muscle contraction independent of AP generation.
A
Drugs, excitatory neurotransmitters, hormones
22
Q
There are stretch activated ion channels in the cell membrane of some smooth muscle that when activated lead to ?
A
depolarization (Ca2+, Cl-, TRPV4, TRPC1, TRPC6)
23
Q
Stretch of smooth muscle causes an internal release of Ca2+ from the SR through the ?
A
ryanodine receptor
24
Q
Stretch has been shown to cause _______ of the myosin light chain leading to contraction
A
phosphorylation
25
In smooth muscle _____ ATPase must be activated
myosin
26
The Ca2+ _______ complex then activates an enzyme known as myosin light chain kinase (MLCK)
calmodulin
27
MLCK phosphorylates the regulatory light chain near the myosin head which ? of the myosin head, ______ its ATPase activity and allows it to interact with actin (conformation change).
alters the conformation, increasing
28
In skeletal and cardiac muscle ATPase activity of myosin head is always ___
high
29
Increased Ca2+ entering-> ______ MLCK activated->___ myosin heads activated-> _______ force generated
increased, more, increased
30
Order these statements in accordance with cross bridge cycling:
1. Ca2+ calmodulin activated myosin light chain kinase (MLCK)
2. Active myosin crossbridges slide along actin and create muscle tension
3. Intracellular Ca2+concentrations increase when Ca2+ enters cell and is released from sarcoplasmic reticulum
4. Intracellular Ca2+ binds to calmodulin (CaM)
5. MLCK phosphorylates light chains in myosin heads and increases myosin ATPase activity
3, 4, 1, 5, 2
31
Cross-bridge cycling is similar but occurs more ____
slowly
32
Order these statements in the context of cross-cycling:
1. Power stroke begins when Pi is released
2. Myosin releases ADP at the end of the power stroke
3. Myosin hydrolyzes ATP. Energy from ATP rotates the myosin head to the cocked position. Myosin binds weakly to actin
4. ATP binds to myosin. Myosin released actin.
4, 3, 1, 2
33
In relaxation in smooth muscle Ca2+ is moved back to the SR and extracellular space Ca2+ removal does not _____ lead to relaxation. The regulatory light chain must be ________ by myosin light chain phosphatase
immediately, dephosphorylated
34
Even after _________ of regulatory light chain some smooth muscle can maintain force for an extended period of time with ____ ATP use known as latch state (unknown process)
dephosphorylation, little
35
_______, ______ and ______ molecules can alter smooth muscle Ca2+ sensitivity by modulating myosin light chain phosphatase (MLCP)
Neurotransmitters, hormones, paracrine
36
Increasing Ca2+ entry and Ca2+ sensitivity to increase ?
contractile force
37
Contractile force in smooth muscle largely depends on the ?
balance of MLC phosphorylation and dephosphorylation
38
MLC phosphorylation is regulated by the Ca2+-CaM complex, which in turn depends on levels of ?
intracellular Ca2+
39
Smooth muscle can regulate Ca2+ over a _____ range than in skeletal or cardiac muscle
wider
40
Inhibiting MLCP or activating MLCK leading to greater contraction at ____ [Ca2+]i
lower
41
The requirement for a circulatory system is a consequence of ? and ?
increasing size, complexity of multicellular organisms
42
The cardiovascular system provides a ? from the blood to cells for nutrients and in the opposite direction for waste.
concentration gradient
43
What is the primary role of the circulatory system?
The distribution of dissolved gases and other molecules for nutrition, growth and repair, while simultaneously removing cellular wastes.
44
What are the three basic functional parts of the circulatory system?
Heart, blood, vessels
45
What are the 3 secondary role of the circulatory system?
1. Chemical signaling to cells by means of circulating hormones or neurohormones
2. Dissipation of heat by delivering heat from the core to the surface of the body
3. Mediation of inflammatory and host defense responses against invading microorganisms
46
What was a very old belief about the body and blood?
Tissues were thought to consume all blood delivered to them and that the liver constantly made new blood
47
What was Dr. William Harvey able to prove?
In one hour the heart pumped more than your entire body weight of blood and that there was no way the liver could constantly produce that much blood
48
Transport in the circulatory system can be divided into 3 types: ?
1. Materials entering the body
2. Materials moved from cell to cell
3. Materials leaving the body
49
What is the heart?
A dual pump driving blood in 2 serial circuits
50
What are the 2 circuits of the heart?
Pulmonary and systemic
51
Carrying blood away from the heart are _____; carrying blood back to the heart are ____
arteries, veins
52
Smallest vessels where transport (transfer) takes place are the ______
capillaries
53
As blood moves through the circulation, a system of valves in the heart and veins ensures that blood flows in ?
one direction
54
What are the 3 most notable circulations within systemic circuit?
-Coronary circuit
-Digestive tract/liver portal system
-Kidney portal system
55
The ____ ____ receives blood from the venae cavae and sends blood to the right ventricle
right atrium
56
The ____ ____ receives blood from the right atrium and sends blood to the lungs
right ventricle
57
The ____ ____ receives blood from the pulmonary veins and sends blood to the left ventricle
left atrium
58
The ____ ____ receives blood from the left atrium and sends blood to the body except for the lungs
left ventricle
59
The ____ ____ receives blood from the systemic veins and sends blood to the right atrium
venae cavae
60
The ____ ____ receives blood from the right ventricle and sends blood to the lungs
pulmonary trunk (artery)
61
The ____ ____ receives blood from the veins of the lungs and sends blood to the left atrium
pulmonary vein
62
The ____ receives blood from the left ventricle and sends blood to the systemic arteries
aorta
63
How does blood flow though the cardiovascular system?
Liquids and gases commonly flow down pressure gradients (ΔP) from regions of high pressure to regions of lower pressure
64
The initial region of high pressure in the cardiovascular system is created by ?
contraction of the heart
65
Blood then flows out of this high pressure region into ?
the lower pressure vessels
66
As blood flows through the vessels pressure is lost due to friction created between ?
the blood and vessel walls
67
The mean blood pressure of the systemic circulation ranges from a high of 93mmHg in the ___ to a low of a few mmHg in the ____ ____
aorta, venae cavae
68
What is the driving presure?
The high pressure created in the ventricles
69
When the heart muscles relax and expand the pressure exerted by the blood within the ventricles ?
decreases
70
Aside from pressure changes within the ventricles many vessels have the ability to constrict or dilate also affecting ?
blood pressure
71
Blood flows from ____ pressure to ____ pressure regions
higher, lower
72
Blood flow in the cardiovascular system needs a pressure gradient, this is created through ?
contraction of the ventricles
73
Flow ∝ ?
ΔP
74
ΔP = ?
P1 - P2
75
The flow of blood in a tube is directly proportional to the pressure gradient at each end of the tube, not the ?
absolute pressure
76
Fluid flows only if there is a ____ pressure gradient
positive
77
Resistance opposes ___
flow
78
While a fluid flows through a tube, the fluid encounters friction from ? and from ?, which opposes flow
the walls of the tube, cells in the blood colliding
79
Flow ∝ 1/?
R
80
Flow (F or Q) = ?/?
ΔP/R
81
Flow is inversely proportional to ?
resistance
82
In a well defined system it is possible to predict the resistance to flow from the geometry of the vessel and the properties of the fluid using what law?
Poiseuille's
83
What is Poiseuille's law?
F =ΔP × (πr^4)/(8ηl)
84
What are the parameters that determine resistance in Poiseuille's equation?
r = radius of the tube
l = length of the tube
η = viscosity of the fluid
85
Larger radius = ___ resistance
less
86
Flow is inversely proportional to both the ? and ?
length of the vessel, viscosity of the liquid
87
Resistance is directly proportional to ? and ?
viscosity of liquid, length of tube
88
In Poiseuille's equation, what remains relatively constant in the CV system?
l and η
89
A shorter length tube will have ___ resistance and more flow
less
90
Velocity depends on the ? and ?
flow rate, cross-sectional area
91
What is velocity of flow?
How fast blood flows past a certain point
92
Velocity (v) = ?/?
Q (flow rate)/A (cross-sectional area)
93
With an equal flow rate, the velocity of blood is more ____ in narrow sections of vessel
rapid
94
The heart is a muscle that _____ contracts, resting only for milliseconds between beats
continuously
95
The heart lies in the center of the ?
thoracic cavity
96
The heart is about the size of a ?
fist
97
The apex angles ? of the body
slightly downward to the left
98
The heart is on the ____ side of the thoracic cavity?
ventral
99
The heart is encased in a tough membranous sac known as the ?
pericardium
100
The pericardium is a _____ walled sac filled with a thin layer of clear pericardial _____
double, fluid
101
The pericardium ____ the external surface of the heart as it beats within the sac
lubricates
102
The _____ occupy the bulk of the heart
ventricles
103
The ____ and _____ attach to the base of the heart
arteries, veins
104
The heart itself is mostly composed of ______ covered by thin inner and outer layers of _____ and _____ tissue
myocardium (cardiac muscle), epithelium, connective
105
________ _____ - allow flow from the atria into the ventricles
atrioventricular valves (AV)
106
Where do you find the tricuspid valve?
Right atrium to the right ventricle. It has 3 flaps.
107
Where do you find the mitral valve?
Left atrium to the left ventricle, and is bicuspid
108
The ___ valves are attached to a papillary muscle in each ventricle by chordae tendineae (tendon. These muscles only supply stability to the valves and are not able to ?
AV, open them
109
One-way flow through the heart is ensured by ?
two sets of valves
110
______ _____ are one way valves that exist between the ventricle and outflow artery
Semilunar valves
111
Semilunar valves have __ cup-like leaflets
3
112
Where is the aortic valve?
From the left ventricle to the aorta
113
Where is the pulmonary valve?
From the right ventricle to the pulmonary artery
114
______ ____ do not need connective tendons due to their shape
Semilunar valves
115
During _____ contraction, the AV valves remain closed to prevent blood flow backward into the atria
ventricular
116
The semilunar valves prevent blood that has entered the arteries from flowing back into the ventricles during ventricular _____
relaxation
117
What are the atrioventricular rings?
Encircle the orifices of the tricuspid and mitral valves
118
Cardiac action potential originates in a ? and spreads through a network of ?
group of cells in the SA node (pacemaker), autorhythmic cells
119
The ? and ? have slower pacemaker activity overridden by that of the SA node.
AV node, purkinje fibres
120
What are the 6 elements of the conduction system of the heart?
SA node, internodal pathways, AV node, AV bundle, bundle branches, purkinje fibers
121
The group of autorhythmic cells with the most rapid ? set the heart rate.
pacemaker activity
122
The atrial muscle has __ special conducting bundles
4
123
What is Backman's bundle?
Conducts action potentials from the SA pacemaker into the left atrium causing contraction
124
What is the purpose of the anterior, middle, and posterior internodal pathways?
Conduct the action potential from the SA node to the AV node, depolarizing the right atrial muscle along the way
125
Atrial conduction is relatively ____
slow
126
There is a layer of connective tissue prevents ____ directly from atria to ventricle
conduction
127
Conduction slows down through the ? to allow blood from atria to empty into ventricles
AV node
128
In ventricular conduction, ? proceeds through the septum to the apex, then spreads up the walls of the ventricles from apex to base
depolarization
129
Ventricular muscles have a ____ arrangement that ensures blood is squeezed _____ from the apex of the heart
spiral, upward
130
Intercalated disks contain _____ that transfer force from cell to cell, and gap junctions that allow _____ signals to pass rapidly from cell to cell
desmosomes, electrical
131
What happens if electrical activity cannot be transferred from the atria to ventricles?
There is a complete conduction block caused by damage in conduction pathway
132
When electrical activity cannot be transferred from the atria to the ventricles, the ? continues to be pacemaker for the atria, but electrical activity does not make it to the ventricles so the ? take over as the pacemaker for the ventricles. This requires an ?
SA node, purkinje fibers, artifical pacemaker
133
These recordings are known as ? and show the summed electrical activity generated by all the cells of the heart
electrocardiograms (ECG’s or EKG’s)
134
Why/how can we record the electrical activity of the heart from the surface of the skin?
Because salt-solutions like our NaCl-based extracellular fluid are good conductors of electricity
135
What was Walter Einthoven's contribution?
Einthoven's triangle, a hypothetical triangle created around the heart when electrodes are placed on both arms and the left leg
136
The sides of Einthoven's triangle are numbered corresponding to the three ? they create. The ECG is recorded one lead at a time, where one electrode acts as a ? electrode and one acts as a ?electrode.
“leads” (pairs of electrodes), positive, negative
137
If the electrical activity of the heart is moving towards the positive electrode of the lead then an _____ deflection is recorded; if it is moving away from a positive electrode is recorded as a ______ deflection; moving perpendicular to the axis of the electrodes causes ?
upward, downward, no deflection
138
ECG’s are a combination of _____ and _____
waves, segments
139
In the ECG:
_____ appear as deflections above or below the baseline
______ are the sections of baseline between two waves
_______ are the combination of waves and segments.
Waves, Segments, Intervals
140
An ECG is divided into waves (?), the segments between the waves (?), and intervals consisting of a combination of waves and segments (?)
P, Q, R, S, T
P-R, S-T
PR, QT
141
What is a P wave?
Atrial depolarization
142
What is a P-R segments?
Conduction through AV node and AV bundle
143
What is the QRS complex?
Ventricular depolarization
144
What is a T wave?
Ventricular repolarization
145
ECGs provide information on ? and ?, ? and even ?
heart rate, rhythm, conduction velocity, condition of tissues in the heart
146
What is the heart rate in an ECG?
P wave to P wave or R-R (tachycardia, bradycardia)
147
In an ECG, is the rhythm of that heart beat (intervals) regular?
Arrhythmia (abnormal rhythm) can be the result of many issues
148
In an ECG, are all normal waves present?
Is each wave P, Q, R, S,T present?
149
Is there one QRS complex for every P wave and is the PR segment constant?
Elongated segments are indicative of damage
150
______ can appear as elongated segments or intervals, altered, missing or additional waves
Arrhythmias
151
What are arrhythmias?
Electrical problems during the generation or conduction of AP’s through the heart
152
What are premature ventricular contractions and how are they perceived?
Purkinje fibres randomly kick in as pacemaker. Perceived as skipped beat or palpitation
153
What can cause premature ventricular contractions?
Due to insufficient oxygen to myocardium, excessive Ca2+, hypokalemia, medications, exercise, high levels of adrenaline
154
What is Long QT syndrome?
Inherited channelopathy, delayed repolarization of the ventricles. Palpitations, fainting, and sudden death due to ventricular fibrillation, can be drug induced
155
What is a cardiac cycle?
One complete contraction and relaxation
156
What are the 2 primary phases of a cardiac cycle?
Diastole and Systole
157
What is diastole?
The time during which cardiac muscle relaxes
158
What is Systole?
The time during which cardiac muscle contracts
159
Because the atria and ventricles do not contract and relax at the same time the events are discussed _______
separately
160
A single cardiac cycle is divided into __ phases
5
161
What are the 5 phases of a single cardiac cycle?
1. Atrial and ventricular diastole, late diastole
2. Atrial systole
3. Isovolumetric ventricular contraction
4. Ventricular ejection
5. Isovolumetric relaxation, early diastole
162
What is atrial and ventricular diastole, late diastole?
Cycle starts with atria relaxed and filling with blood from veins. The ventricles begin to relax, when the ventricles are sufficiently relaxed and pressure in atria exceeds ventricles, AV valve opens and ventricles passively fill with blood from atria.
163
What is atrial systole?
Most blood enters ventricles passively but under normal resting conditions the last ~ “20%” enters when the atria contract
164
What is isovolumetric ventricular contraction?
The ventricles begin to contract, this builds up pressure in the ventricles and causes the AV valves to snap shut (first heart sound s1 “lub”)
Both valves are now closed and then the ventricle continues to contract building up pressure.
165
What is ventricular ejection?
As the ventricles contract pressure in the ventricle exceeds pressure in the outflow arteries (aorta or pulmonary arteries) causing the semi lunar valves to open and blood to flow out
166
What is isovolumetric ventricular relaxation, early diastole?
The ventricles then begin to relax, pressure in the outflow arteries begins to exceed the ventricles causing blood to attempt to flow backward into the ventricles causing the semi lunar valves to snap shut (second heart sound s2 “dub”)
167
What is the A-A' segment in the pressure volume loop of cardiac cycle?
Late diastole
168
What is the A'-B segment in the pressure volume loop of cardiac cycle?
Atrial systole
169
What is the B-C segment in the pressure volume loop of cardiac cycle?
Isovolumetric contraction
170
What is the C-D segment in the pressure volume loop of cardiac cycle?
Ventricular ejection
171
What is the D-A segment in the pressure volume loop of cardiac cycle?
Isovolumetric relaxation
172
The ? : starts at ESV (end systolic volume; not all blood is pumped out during a ventricle contraction, the volume of blood left over after contraction is ESV). Pressure in ventricle is lower than atria and the AV valve opens causing the ventricle to passively fill with blood (majority is passive)
A-A' segment
173
The ? : atria contracts forcing more blood into the ventricle slightly increasing volume and pressure. At the end, the maximal amount of blood is in the ventricles, this occurs at the end of ventricular diastole and is termed the end diastolic volume
A’-B segment
174
The ? : the ventricle begins contracting closing AV valve, continued contraction causes a large increase in pressure within the ventricle
B-C segment
175
The ? : Once pressure in ventricle rises above ~80mm Hg, it exceeds the aorta and the aortic valve opens causing a rapid ejection of blood. Pressure still rises as the ventricle continues to contract. Part way through this segment the ventricle begins to relax and pressure begins to drop but blood still flows due to the inertia
C-D segment
176
The ? : pressure in aorta begins to exceed ventricle causing semi-lunar valve to close, ventricle continues to relax
D-A segment
177
What is the Wiggers Diagram?
Follows left heart and aortic pressures, left ventricular volume, and the ECG through one cardiac cycle
178
What is signified by 'D' in a wiggers diagram?
Ventricle relaxes, pressure in atria begins to exceed ventricle. AV valve opens and you get the passive filling of the ventricle. Atria then contracts increasing the volume and pressure slightly
179
What is signified by 'C' in a wiggers diagram?
Ventricle beings to contract, increasing pressure within ventricle causing the AV valves to snap shut (S1)
180
What is signified by 'E' in a wiggers diagram?
Represents maximal ventricle volume (EDV)
181
In the wiggers diagram, the ventricle continues to contract until it exceeds pressure in aorta at point __
A
182
In the wiggers diagram, the aortic valve opens and you get a rapid ejection of blood from point __ to __
E to F
183
In the wiggers diagram, the ventricle begin to relax, and at point __ pressure in aorta starts to exceed ventricle causing the semi-lunar valve to snap shut (S2). Ventricle continues to relax until it is lower than the atrium and passive filling of the ventricle occurs once again
B
184
What is end diastolic volume (EDV)?
The maximal volume in the ventricle, after ventricular filling, 70kg man at rest ~135ml
185
What is end-systolic volume (ESV)?
the minimal amount of blood in the ventricles, blood left after ventricular contraction, ~65ml
186
What is stroke volume (SV)?
amount of blood ejected during a single ventricular contraction, ~70ml
187
Why is stroke volume ~70ml?
Because SV = EDV-ESV, so 135-65 = 70ml
188
The ESV provides a ?
safety margin
189
A more forceful contraction of the heart will cause a _____ stroke volume resulting in a ______ in the ESV.
larger, decrease
190
Stroke volume can increase to as high as 100ml and is modulated by the ?, ? and by certain ?
autonomic nervous system, venous return, drugs
191
What is the ejection fraction (EF)?
The percentage of EDV that is ejected from the heart (SV)
192
How to calculate the ejection fraction?
SV/EDV = 70/135 - 52%
193
How do you calculate total blood flow (cardiac output)?
Heart rate x stroke volume
194
What is cardiac output (CO)?
Flow of blood delivered from one ventricle in a given time period (usually 1 minute)
195
Cardiac output is a measure of cardiac ______?
performance
196
The output from a single heartbeat, from either the left or right ventricle is the ?
Stroke volume (SV) L/beat or mL/beat
197
What is heart rate (HR) measured in?
beats per minute (bpm)
198
What is the average heart rate?
72bpm
199
What is the average stroke volume?
70mL/beat
200
What is the average cardiac output of a 70kg male?
~5L/min
201
CO’s of the pulmonary and systemic circuit are usually ______
identical
202
If offset, blood tends to pool in the circuit feeding the _____ side of the heart
weaker
203
CO can raise to__-__L/min during exercise
30-35
204
Steve has an end diastolic volume of 150ml, an end systolic volume of 30 ml and a heart rate of 90 bpm. Calculate Steve’s cardiac output
CO= SV x HR
CO=(EDV-ESV) x HR
CO=(150 ml/b-30 ml/b) x 90 b/m
CO=10800 ml/min or 10.8L/min
205
Cardiac output can be modified by adjusting ?
heart rate
206
Cardiac output can be adjusted by modulating ?
stroke volume
207
Stroke volume is directly related to the force generated by the ?.
cardiac muscle during contraction
208
Normally as force of contraction increases, ? increases
stroke volume
209
Two factors determine the amount of force generated by cardiac muscle: ?
1. Contractility of the heart
2. The length of the muscle fibers at the beginning of contraction
210
The length of the muscle fibres at the beginning of contraction is determined by the ?
volume of blood in the ventricle at the beginning of contraction (end-diastolic volume)
211
Contractility is controlled by the ?
nervous and endocrine systems
212
Any chemical that affects contractility is called an ? and its influence is referred to as an ?
inotropic agent, inotropic effect
213
Chemicals increasing contractility have a ____ inotropic effect and ones decreasing contractility a _____ inotropic effect.
positive, negative
214
What are two common catecholamines?
Norepinephrine and epinephrine
215
? released from the sympathetic neurons or adrenal medulla cause a positive inotropic effect regardless of EDV
Catecholamine's (Norepinephrine and epinephrine)
216
Contractility increases as the amount of Ca2+ available for contraction _____
increases
217
Order these statements in order for sympathetic modulation of contraction (stroke volume):
1. Phosphorylation of ryanodine receptors enhances sensitivity to Ca2+, increasing release of Ca2+ from the sarcoplasmic reticulum
2. Increases rate of myosin
3. Phosphorylation of Ca2+ channels increases calcium conductance during action potentials
4. Phosphorylation of SERCA (PLN) increases the speed of Ca2+ re-uptake which increases Ca2+ storage
3, 1, 2, 4
218
Increasing sarcomere length increases ?
force of contraction (stroke volume)
219
Skeletal length tension relationship explained by degree of overlap between ?
thick and thin filaments.
220
Raising sarcomere length ____ the Ca2+ sensitivity of the myofilaments. A stretched sarcomere has a ______ diameter which may reduce the distance that Ca2+ needs to diffuse _____ probability of cross-bridge cycling
increases, decreased, increasing
221
Raising sarcomere length puts additional tension on stretch-activated Ca2+ channels, _______ Ca2+ entry from extracellular space and ______ Ca2+ induced Ca2+ release _______ tension
increasing, increasing, increasing
222
What is Frank-starling's law of the heart?
The amount of force developed by the cardiac muscle of a ventricle, depends on the initial stretch of the ventricle walls
223
The degree of myocardial stretch prior to contraction is known as the ?
preload on the heart
224
According to frank-starling law, stroke volume increases with increasing ?
end-diastolic volume
225
What is a Starling curve?
Length-force relationships in the intact heart
226
What is venous return?
The rate of blood flow back to the heart
227
___ is normally determined by venous return
EDV
228
Increased venous return ______ venous pressure resulting in _____ atrial filling leading to ______ ventricle filling
increases, increased, increased
229
What are the 3 factors that affect venous return?
1. Skeletal muscle pump
2. Respiratory pump
3. Sympathetic constriction of veins
230
How does the skeletal muscle pump affect venous return?
Skeletal muscle activity compresses veins in the extremities pushing blood back to the heart. Increased muscle activity of the extremities can increase venous return
231
How does the respiratory pump affect venous return?
During inspiration the chest expands and diaphragm moves down creating a subatmospheric pressure in the thoracic cavity, this draws blood into the vena cava that exist within this cavity, and veins in the abdomen are compressed also forcing blood back to the heart
232
How does sympathetic constriction of the veins affect venous return?
Decreasing their volume squeezing blood back towards the heart
233
What is afterload?
The is the end load against which the heart contracts to eject blood
234
Afterload is primarily determined by the combination of the ___ and the ?
EDV, pressure in the outflow artery prior to contraction (aorta or pulmonary artery).
235
Afterload can be increased in _____ situations (eg. increased arterial blood pressure, decreased aortic compliance)
pathological
236
The functional model of the cardiovascular system shows the heart and blood vessel as a ?
single closed loop
237
Each side of the heart functions as an ______ pump
independent
238
Systemic veins serve as an _____ volume reservoir
expandable
239
Exchange between the blood and cells takes place only at the ?
capullaries
240
The arterioles are the site of _____ resistance
variable
241
The elastic system arteries are a _______ reservoir that maintains blood flow during ventricular relaxation
pressure
242
What is the progressive branching of vessels?
Aorta > Arteries > Arterioles > Capillaries > Venules > Veins > Vena Cava
243
All vessels contain inner layer of ? and can be wrapped in a combination of _____ tissue, ____ muscle or _____ tissue
thin endothelial cells, elastic, smooth, fibrous
244
In vessels, the endothelial cells were thought to only be a ?
passive barrier
245
______ are important in secreting paracrines (substances that signal changes in near by cells) regulation of blood pressure, blood vessel growth, as well as absorption of materials.
vessels
246
The amount of smooth muscle in each vessel type ____
varies
247
In most vascular smooth muscle there is always a state of ?
partial contraction (tone)
248
Vascular smooth muscle can be influenced by a variety of substances including _______, ______, ______. These substances bind receptors ultimately resulting in an increase in ?
neurotransmitters, hormones, paracrines, cytosolic Ca2+ causing contraction
249
Arteriole diameter is controlled by ?
tonic release of norepinephrine
250
Moderate signal rate results in a blood vessel of _______ diameter
intermediate
251
As the signal rate increases, the blood vessel ____
constricts
252
As the signal rate decreases, the blood vessel _____
dilates
253
Arteriole wall is _____ muscle
smooth
254
Metarterioles can act as ?
bypass channels
255
Precapillary sphincters can close off capillaries in response to ?
local signals
256
Systemic circuit begins with a single aorta that branches off to ?
major arteries
257
Arteries have walls that are both ____ and _____. Thick _____ muscle layer and large amount of ?
stiff, springy, smooth, elastic and fibrous connective tissue
258
Arteries branch into smaller ______
arterioles
259
Arterioles, capillaries and venules make up the _______
microcirculation
260
Across the microcirculation you have _______ which act as a capillary bypass vessels, and also for WBC’s
metarterioles
261
______ are the smallest vessels in the cardiovascular system, where the majority of exchange between the blood and interstitial space occur.
capillaries
262
______ have a single thin endothelial layer surrounded by a basal lamina (extracellular matrix)
capillaries
263
____ can normally passively diffuse across the endothelial cells
gases
264
Capillaries are linked by ? that also aid in the transport of small solutes and water
interendothelial junctions
265
Some cells contain fenestrations, which are ?
Membrane lined conduits running through them to allow the transport
266
Capillaries are often surrounded by ?
pericytes (BBB)
267
What are the 3 kinds of capillaries?
1. Continuous
2. Fenestrated
3. Discontinuous (sinusoidal)
268
____ capillary: most common, thicker endothelial cells that do not contain fenestrations. Only allow passage of water and small ions through intercellular junctions
Continuous
269
______ capillary: thin endothelial cells that are perforated with fenestrations. The fenestrations often have a thin diaphragm. Small molecule passage
Fenestrated
270
_______ capillary: lack a basal membrane, have large open fenestrations as well as gaps between the endothelial cells. (liver and spleen)
Discontinuous (sinusoidal)
271
What are the 3 methods of transport in capillaries?
Transcellular, paracellular, transcytosis
272
Veins are more numerous and have a larger volume, thinner walls and less muscle tissue in comparison to _____ making the venous circulation the _____ reservoir of the circulatory system
arteries, volume
273
What is Angiogenesis?
The formation of new blood vessels
274
Adult microcirculation is considered _____, but what are some exceptions?
constant, would healing, endurance training, inflammation, tumor growth, endometrium during menstrual cycle
275
? (mitogens-pro mitotic) activate receptors on endothelial cells
Angiogenic growth factors
276
Activated endothelial cells produce _____ that degrade the basal lamina so it can move away from the parent vessel
proteases
277
Endothelial cells proliferate into the surrounding matrix and form ____ towards the angiogenic stimulus in tandem. They then form loops to become a full-fledged ? as cells migrate to the site of angiogenesis
sprouts, vessel lumen
278
Angiogenesis is a necessary part of the process in the progression of _____ from small, localized neoplasms to larger, growing, and potentially metastatic tumors
cancer
279
What is Coronary Heart Disease?
Type of heart disease where the arteries of the heart cannot deliver enough oxygen-rich blood to the heart
280
Ventricular contraction creates the force necessary to ?
propel blood through the cardiovascular system
281
?: contraction of the ventricles pushes blood into the elastic arteries, causing them to stretch
Ventricular contraction
282
?: elastic recoil in the arteries maintains driving pressure during ventricular diastole
Ventricular relaxation
283
Aorta and large arteries sustain driving pressure during ?
ventricular diastole
284
Order these statements in terms of ventricular contraction:
1. Aorta and arteries expand and store pressure in elastic walls
2. Semilunar valve opens. Blood ejected from ventricles flows into the arteries
3. Ventricle contracts
3, 2, 1
285
Order these statements in terms of ventricular relaxation:
1.Semilunar valve shuts, preventing flow back into ventricle
2. Isovolumic ventricular relaxation
3. Elastic recoil of arteries sends blood forward into rest of circulatory system
2, 1, 3
286
Blood pressure is highest in the ____ and decreases throughout circuit
aorta
287
Aortic pressure highest during ?: systolic pressure (120 mm Hg) and lowest during ?: diastolic pressure (80 mm Hg).
ventricular contraction (systole), ventricular relaxation (diastole)
288
What is pulse pressure?
The difference between the systolic and diastolic pressure
289
How do you calculate pulse pressure?
Systolic pressure - diastolic pressure
290
What is the pulse pressure in the aorta?
120mmHg - 80mmHg = 40mmHg
291
Pulse pressure normally only exists on the ? side of circuit
arterial/arteriole
292
Mean arterial blood pressure reflects the driving pressure for ?
blood flow
293
Mean arterial blood pressure is commonly measured in a major artery (brachial) as reflection of ?
ventricle (driving) pressure
294
The mean arterial blood pressure is not simply the average of the systolic and diastolic pressures (100 mm Hg) because ?
equal amounts of time are not spent in systole and diastole
295
How would you calculate mean arterial pressure?
Diastolic pressure + 1/3 (pressure pressure)
296
_______ represents when the blood pressure falls too low (<90/60). This can cause the driving force for blood flow to be inadequate to overcome the opposition by _______
Hypotension, gravity
297
________ represents when the blood pressure is chronically elevated (>140/90)
Hypertension
298
High pressure on the vessel walls can cause them to become ? and leak. If this occurs in the brain it is called a ? and may cause a loss of neurological function, commonly referred to as a ____.
weakened or even rupture, cerebral hemorrhage, stroke
299
What is a sphygmomanometer?
A blood pressure monitor, or blood pressure gauge, is a device used to measure blood pressure
300
What is the normal range for systolic and diastolic blood pressure?
Systolic: >120
Diastolic: >80
301
Mean arterial blood pressure is the balance between ?
blood flow into the arteries and blood flow out of the arteries
302
Increased volume in arteries = ______ arterial blood pressure
increased
303
Most cases of hypertension believed to be due to ?
increased peripheral resistance without changes in cardiac output
304
What are the 2 factors that influence arterial blood pressure?
1. Blood volume
2. Relative distribution of blood between arterial and venous blood vessels
305
Blood volume is determined by ?
Fluid intake
Fluid loss, which may be passive or regulated at kidneys
306
Relative distribution of blood between arterial and venous blood vessels is determined by ?
diameter of the veins
307
Arteries are low-volume vessels that contain ~___% of the total blood volume at any one time. Veins are high volume vessels and hold ~__% of the circulating blood volume at any one time
11, 60
308
Changes in blood volume affect blood ?
pressure
309
Small changes in blood volume occur from ingestion of food and liquids, primarily resolved by _____
kidneys
310
Decreases in blood volume require an ?, ? and ?
integrated response from the kidneys, the cardiovascular system (increase sympathetic output), ingestion of fluid
311
Resistance is highest within the ______
arterioles
312
Area along the curve with the greatest drop in pressure should coincide with the ?
largest increase in resistance.
313
Vessels with the smallest radius theoretically should have the ? Is this the case?
highest resistance (capillaries), no
314
Aggregate (total) resistance not only depends on the ? but also on how ?
radius of each vessel, vessels are arranged (series vs parallel)
315
What is the difference in calculation between vessels arranged in a series vs. arranged in parallel?
Series: Req = R1 + R2 + R3
Parallel: Req = 1/R1 + 1/R2 + 1/R3
316
Resistance in the arterioles contributes >__% of total resistance to flow in cardiovascular system
60
317
Arteriolar resistance is influenced by both ? control mechanisms that alter the vascular smooth muscle changing the radius of vessels greatly influencing ?
local and systemic, resistance
318
How is resistance mathematically related to radius?
R ∝ 1/r^4
319
Local control of arteriolar resistance matches tissue blood flow to the ?: in the heart and skeletal muscle, these local controls often take precedence over ?
metabolic needs of the tissue, reflex control by the CNS
320
Sympathetic reflexes mediated by the CNS maintain ? and govern ? for certain homeostatic needs such as temperature regulation
mean arterial pressure, blood distribution
321
Hormones-particularly those that ?, influence blood pressure by acting directly on the arterioles and by altering autonomic reflex control
regulate salt and water excretion by the kidneys
322
The myogenic theory of autoregulation states that ?
Some vascular smooth muscle has the ability to regulate its own state of contraction
323
An increase in blood pressure causes the vascular smooth muscle in the wall of the arteriole to stretch, which then causes the ?
vascular smooth muscle to contract, leading to vasoconstriction
324
Arterioles contain a variety of ? TRP channels, particularly TRPV2, TRPC6, and TRPM4 that are thought to be responsible for the mechano-depolarization leading to ?
stretch activated, a myogenic response
325
______ alter vascular smooth muscle
Paracrines
326
Local control of blood flow is important in allowing ? (arteriole or precapillary sphincters)
individual tissues to regulate their own blood supplies
327
Active hyperemia matches blood flow to ?
increased metabolism
328
What are some paracrines that alter vascular smooth muscle?
Metabolism related: low oxygen, high carbon dioxide, NO, H+, lactate, adenosine
Non-metabolism related: kinins and histamine (inflammation), serotonin
329
The main determinant of resistance in the majority of arterioles is the _____ nervous system
sympathetic
330
primarily sympathetic neurons innervate arterioles and tonically control arteriolar diameter through activation or deactivation of ?
α1 adrenergic receptors
331
Epinephrine has a low ____ for alpha receptors that cause vasoconstriction and a ____ affinity for B2 adrenergic receptors which lead to vasodilation
affinity, high
332
Parasympathetic = bradycardia/tachycardia; sympathetic = bradycardia/tachycardia
bradycardia, tachycardia
333
What is bradycardia?
A slower than normal heart rate
334
What is tachycardia?
A heart rate over 100 beats a minute
335
At rest regional amount of blood flow depends on the number and size of ?
arteries feeding the organ
336
Regional variations can occur because arterioles are arranged in ? (in addition to series branching) meaning they all receive blood at the same time
parallel
337
Total blood flow through all the arterioles equals the ?
CO
338
Flow for each arteriole depends on the _____, if an arteriole constricts resistance _______ and blood flow through that arteriole ________
resistance, increases, decreases
339
Blood is diverted away from high resistance arterioles towards ? and thus takes the path of least resistance
low resistance arterioles
340
Main integrating center: ?. Primary function: ensures adequate blood flow to the brain and heart by maintaining ?
medullary cardiovascular control center (CVCC), sufficient mean arterial pressure
341
The primary reflex pathway for homeostatic control of mean arterial blood pressure is the ?
baroreceptor reflex
342
Baroreceptors are ______ active stretch sensitive mechanoreceptors that are situated on the ____ and on the ?
tonically, aorta, carotid artery
343
When there is an increase in blood pressure the baroreceptors sense the stretch in the artery walls and ______ their firing rate
increase
344
Decrease blood pressure > _____ firing rate
decrease
345
Baroreceptor reflex is _______ active
constantly
346
Orthostatic hypotension triggers ?
baroreceptor reflex
347
Every morning when you stand up out of bed your baroreceptor reflex is ?
highly engaged
348
Peripheral chemoreceptors located on the ? and ?
aortic arch, carotid artery
349
Peripheral chemoreceptors sense alterations in ? as well as changes in ?
blood-gas concentrations ([O2], [CO2]), blood pH
350
Peripheral chemoreceptors send information back to the ? which then results in a change in autonomic output to return blood gas levels to ?
cardiovascular control center, normal values
351
Peripheral chemoreceptor activation changes ventilation within the ?
respiratory system
352
The _______ is capable of altering cardiovascular function in response to emotional stress
hypothalamus
353
What is the Vasovagal syncope?
Faint in response to sudden emotional distress, sight of blood, phlebotomy (needle insertion), acute pain
354
The combination of decreased CO and decreased peripheral resistance cause a large fall in mean arterial pressure, primarily ?
parasympathetic decrease in HR
355
Capillary density in any tissue is related to its ?
metabolic activity
356
What is bulk flow?
The mass movement of fluid as the result of hydrostatic or osmotic pressure gradients
357
If bulk flow is resulting in fluid moving into the capillaries, _________is taking place
absorption
358
If bulk flow is resulting in the movement of fluid out of the capillaries this is ______
filtration
359
What is hydrostatic pressure (Ph)?
The pressure in the blood vessels drives fluid out of the capillaries through pores and cell junctions (filtration)
360
What is colloid osmotic pressure/oncotic pressure (π)?
The pressure that draws fluid into the capillaries is the pressure created by plasma proteins in the blood
361
π is _____ in the capillary and _____ the interstitial space π (zero)
steady, exceeds
362
Ph in vessels ______ as blood travels through the capillaries due to the ? and ?
decreases, resistance encountered, exceeds interstitial Ph (zero)
363
At the _____ end PH exceeds π causing net filtration; at the _____ end π exceeds PH and there is absorption
arterial, venous
364
Overall, there is a net filtration from the entire capillary network resulting in a loss of ? of fluid/day from the blood
3L
365
High hydrostatic pressure forces fluid ____ of the capillary
out
366
Low colloid osmotic pressure of proteins within the capillary pulls fluid ____ the capillary
into
367
What is the equation for Net Pressure?
Hydrostatic pressure - colloid osmotic pressure
368
Positive net pressure indicates _______; negative net pressure indicates _______
filtration, absorption
369
Lymph fluid empties into the _____ circulation
venous
370
Lymphatic vessels assist the cardiovascular system with returning fluid and proteins lost through ?
the capillaries
371
? vessels have single endothelial cell layer
Lymphatic
372
Lymphatic vessels contain large ________ junctions that act like one-way valves
interendothelial
373
In the initital lymphatic segment, the interstitial hydrostatic pressure is _____ than inside the lymphatic causing the microvalves to open and fluid to ?
higher, flow in
374
As it fills up with fluid the lymphatic hydrostatic pressure _____ interstitial, the microvalves close and the ?
exceeds, secondary valves open
375
Collecting lymphatics contain ? that actively contract to propel fluid and one way valves to prevent backflow, skeletal muscle assists as well
smooth muscle
376
What is an edema?
An abnormal accumulation of fluid in the interstitial space
377
What are the 2 causes of an edema?
1. Inadequate lymph drainage
2. A disruption in normal balance between capillary filtration and absorption
378
What are the 3 causes of the disruption between capillary filtration and absorption?
i. Increased capillary hydrostatic pressure (heart failure)
ii. decrease in plasma protein concentration (malnutrition, liver failure)
iii. increase in interstitial proteins (excessive leakage of proteins out of capillaries):injury, inflammation
379
With each branching of a vessel, the two new branches always have a _____ total cross-sectional area than the parent vessel
higher
380
The rate at which blood flows through the capillaries plays a role in the efficiency of exchange between the blood and ______
the interstitial fluid
381
How would you calculate velocity of blood?
Flow rate/ c.s. area
382
Single capillaries have a very ____ cross-sectional area BUT all the capillaries together have a very ____ cross-sectional area
small, large
383
The ____ velocity ensures adequate gas and nutrient exchange at the capillaries
slow
384
Velocity of blood flow depends on the ?
total cross-sectional area
385
Risk factors for cardiovascular disease include: ?
Uncontrolled, controlled, and a combination of both
386
What are some uncontrolled risk factors in cardiovascular diseases?
age, sex, family history of early CVD, genetics
387
What are some controlled risk factors in cardiovascular diseases?
cigarette smoking, obesity, sedentary lifestyle and untreated hypertension
388
What are some combination risk factors in cardiovascular diseases?
diabetes, hyperlipidemia
389
What is atherosclerosis?
Inflammatory process leading to hardening or narrowing of arteries
390
Clinicians concerned with two types of lipoproteins: ?
1. High-density lipoprotein-cholesterol complexes (HDL-C)
2. Low-density lipoprotein-cholesterol complexes (LDL-C)
391
High levels of ? associated with lower risk of heart attack; while elevated levels of ? is associated with coronary heart disease
HDL-C, LDL-C
392
Necessary for cholesterol transport into cells, ? proteins are digested to amino acids and the freed cholesterol is used to make cell membranes and steroid hormones
LDL-C’s
393
The development of atherosclerotic plaques is a process that develops over ?
years
394
Order these statements for the development of atherosclerotic plaques:
1. Smooth muscle cells, attracted by macrophage cytokines, begin to divide and take up cholesterol
2. Fibrous scar tissues forms to wall off the lipid core
3. Macrophages may release enzymes that dissolve collagen and convert stable plaques to unstable plaques
4. Macrophages ingest cholesterol and become foam cells
5. Calcifications are deposited within the plaque
6. A lipid core accumulates beneath the endothelium
7. LDL-cholesterol accumulates between the endothelium and connective tissue and is oxidized
8. Platelets that are exposed to collagen activate and initiate a blood clot
9. Smooth muscle cells divide and contribute to thickening of the intima
7, 4, 1, 6, 2, 9, 5, 3, 8
395
If a clot blocks blood flow to the heart muscle, a ? ensues
myocardial infarction (heart attack)
396
In a myocardial infarction, the ____ of O2 leads to ATP supply declining, the contractile cells become unable to _____ Ca2+ from cytosol. ___ intracellular [Ca2+] closes gap junctions in the damaged cells, electrically _____ them.
lack, remove, High, isolating
397
If the damaged region of myocardium is large, disruption can cause an ? potentially leading to cardiac arrest or death
irregular heart beat (arrhythmia)
398
? in brain vasculature account for 50% of strokes
Atherosclerosis
399
Hypertension is a failure of _______
homeostasis
400
Doubles the risk for cardiovascular disease for each ? mmHg increase in blood pressure above the baseline value of ?
20/10, 115/75
401
Approx 90% of hypertensive patients have essential (primary) hypertension with no definitive cause besides ? These patients have normal cardiac output, but elevated ?
genetics, peripheral resistance
402
What are the 2 biggest effects of hypertension?
Adaption of the baroreceptors to higher pressure with a down regulation of their activity
Risk factor for atherosclerosis, the increased pressure exerted on arterial walls damages the endothelial cell lining and promotes plaque formation
403
Hypertension increases _________
afterload
404
In hypertension, over time the heart must overcome the increased force causing myocardial contractile cells to undergo _____. Eventually the heart cannot meet workload and begins to ?
hypertrophy, fail
405
What is hypertrophic cardiomyopathy?
The walls of the left ventricle become thick and stiff. Over time, the heart can't take in or pump out enough blood during each heartbeat to supply the body's needs.
406
What are the 4 main hypertension treatments?
1. Ca2+ channel blockers
2. Diuretics
3. Beta blockers
4. ACE inhibitors and angiotensin receptor blockers
407
? to relax the vascular smooth muscle and/or decrease CO (HR and force of contraction)
Ca2+ channel blockers (L-type)
408
_______ increase urination removing excess fluid to decrease blood volume
Diuretics
409
Beta blockers block ?
B1 adrenergic receptors decreasing CO
410
ACE inhibitors and angiotensin receptor blockers prevent _______ from renin-angiotensin aldosterone axis
vasoconstriction
411
_____ is a connective tissue composed of cellular elements suspended in an extensive fluid matrix that circulates in the CV system
blood
412
~5L of blood is composed of ____ plasma, which is ____ water and ___ proteins (globulins)
~3L, 92%, 7%
413
Interstitial fluid has ____ concentration of proteins, whereas the plasma has a ____ concentration of proteins. Interstitial fluid has ____ dissolved oxygen, whereas the plasma has a ____ amount of dissolved oxygen
less, high, less, high
414
What is the source and function of albumins?
Source: liver
Function: major contributors to colloid osmotic pressure of plasma; carriers for various substances
415
What is the source and function of globulins?
Source: liver and lymphoid tissue
Function: clotting factors, enzymes, antibodies, carriers for various substances
416
What is the source and function of fibrinogen?
Source: liver
Function: forms fibrin threads essential to blood clotting
417
What is the source and function of transferrin?
Source: liver and other tissues
Function: iron transport
418
Total blood volume: ~__-__% of total body weight: ___/1 kg body weight in an adult female and ~____/kg body weight in an adult male
7-8, 70mL, 80mL
419
What is the hematocrit?
The fraction of the total column occupied by RBC’s (40-45%)
420
What is the Buffy coat?
WBC’s and platelets (1%<)
421
What is Plasma?
Pale white solution of electrolytes, plasma proteins, carbohydrates and lipids (55-60%)
422
What is Hematopoiesis?
Production of blood cells
423
In an adult, where does hematopoiesis occur?
Pelvis, spine, ribs, cranium, and proximal ends of long bones
424
___% of cells produced are WBC’s (short lifespan), ___% RBC’s (4 months)
75, 25
425
Bone marrow consists of blood cells in different stages of development and supporting tissue known as the _____?
stroma
426
Stroma is composed of?
Fibroblast-like reticular cells, collagenous fibers, and extracellular matrix
427
_________: lineage development guided by cytokines (cell signaling molecules)
Hematopoiesis
428
In the bone marrow, all cells start as a ?
pluripotent hematopoietic stem cell
429
Cells like lymphocyte stem cells, uncommitted stem cells, megakaryocyte, erythoblast, and reticulocytes are found in ?
bone marrow
430
What are cytokines?
Proteins or peptides released from one cell that affect growth or activity in another cell
431
What is the site of production of erythropoietin (EPO), and what does it influence in terms of growth/differentiation of?
Site of production: kidney cells primarily
Influences Growth/differentiation of: red blood cells, stimulated by low O2
432
What is the site of production of thrombopoietin (TPO), and what does it influence in terms of growth/differentiation of?
Site of production: liver primarily
Influences Growth/differentiation of: megakaryocytes (platelets)
433
What is the site of production of colony-stimulating factors, interleukins, stem cell factors, and what does it influence in terms of growth/differentiation of?
Site of production: endothelium and fibroblasts of bone marrow, leukocytes
Influences Growth/differentiation of: all types of blood cells; mobilizes hematopoietic stem cells
434
What is Erythropoiesis?
RBC production (EPO)
435
What is Leukopoiesis?
Leukocyte (WBC) production (CSF’s)
436
What is Thrombopoiesis?
Thrombocyte (platelet) production (TPO)
437
What are red blood cells (RBC)s also known as?
erythrocytes
438
______ are the most abundant cell type in the blood (5 million/ul) (~4 month lifespan)
RBCs (erythrocytes)
439
_____ are non-nucleated biconcave cells with diameter ~7.5um
RBCs (erythrocytes)
440
What is the significance of the shape of RBCs (erythrocytes)?
Their distinctive shape increases surface to volume ratio, decreases diffusion distance
441
RBC’s have three major tasks: ?
1. Carrying O2 from the lungs to the systemic tissue
2. Carrying CO2 from the tissues to the lungs
3. Assisting in the buffering of acids and bases.
442
How do you get an erythrocyte?
Erythroblast → Exocytosis of nucleus / loss of mitochondria and ribosomes → reticulocyte → erythrocyte
443
What kind of micrograph shows the biconcave disk shape of RBCs?
Scanning electron (SEM)
444
The ______ is what creates the unique shape of RBCs
cytoskeleton
445
The biconcave disk shape of RBCs allow them to ?, respond to ?, and provide ?
squeeze through capillaries, osmotic changes, evidence of disease
446
Erythrocytes placed in a _____ medium shrink, but the rigid cytoskeleton remains intact, creating a ____ surface. These cells are said to be ?
hypertonic, spiky, crenated (notched)
447
Erythrocytes placed in a _____ medium swell and lose their biconcave disk shape
hypotonic
448
Abnormal ______ in sickle cell disease can cause RBCs to change shape
hemoglobin
449
RBC’s mainly consist of _______
hemoglobin
450
What is hemoglobin?
The O2 transport protein ~96% of dry weight
451
A hemoglobin molecule is composed of __ protein globin chains, each centered around a ____ group. In most adult hemoglobin, there are ___ alpha chains and ___ beta chains
4, heme, two, two
452
What are the 4 kinds of globulin proteins?
Alpha, beta, gamma, delta
453
Each heme group consists of a _____ ring with an iron atom in the center
porphyrin
454
__% of iron in the body found in heme groups of hemoglobin, each heme group can bind ?
70, one oxygen (O2) molecule
455
Hemoglobin synthesis requires ____
iron
456
Order these statements in accordance to hemoglobin synthesis:
1. Transferrin protein transports Fe in plasma
2. RBCs live about 120 days in the blood
3. Bilirubin and metabolites are excreted in urine and feces
4. Iron (Fe) ingested from the diet
5. Bone marrow uses Fe to make hemoglobin (Hb) as part of RBC synthesis
6. Liver metaboizzes bilirubin and excretes it in bile
7. Fe absorbed by active transport
8. Spleen destroys old RBCs and converts Hb to bilirubin
9. Liver stores excess Fe as ferritin
4, 7, 1, 5, 2, 8, 3, 6, 9
457
What are white blood cells also known as?
Leukocytes
458
What is the main purpose of WBCs (leukocytes)?
defending against infection
459
What are the 2 major groups of WBCs?
1. Granulocytes
2. Non-granule containing lymphocytes and monocytes
460
_______: contain cytoplasmic granules visualized under microscope. Brief lifespan in the blood < 12hours, but if activated can migrate into tissues for longer time.
Granulocytes
461
What are the 3 granulocytes?
Neutrophil, eosinophil, basophil
462
What is a neutrophil?
Most abundant leukocyte, contain granules with lysosomal enzymes capable of digesting foreign material (phagocytosis)
463
What is an eosinophil?
Granules contain Major Basic Protein (MBP) which is toxic to parasites and other enzymes. Important in response to virus’ and in allergic reactions
464
What is a basophil?
Least common granulocyte, granules contain histamine, heparin and peroxidase and play a role in allergic reactions
465
What are the two categories of Non-granule containing lymphocytes and monocytes?
1. Lymphocytes
2. Monocytes
466
What are lymphocytes?
For adaptive immunity
467
What are the two types of lymphotcytes?
T-lymphocytes (T-Cell)
B lymphocytes (B-cell)
468
What are T-cells?
70-80% of all lymphocytes and responsible for cell mediated immunity, does not involve antibodies
469
What are B-cells?
Responsible for humoral immunity, make antibodies to antigens
470
What are monocytes?
spend life in peripheral tissues developing into macrophages
471
What are the two purposes of monocytes?
1. Phagocytosis of pathogens or cellular debris
2. Present antigens to lymphocytes
472
________ are nucleus-free fragments, 2-3um in diameter in their inactive state
Platelets (thrombocytes)
473
A single ________ can produce thousands of platelets ~10 day life span
megakaryocyte
474
150-400 000 platelets per 1__ of blood.
ul
475
Platelets contain two special types of granules: ?
1. Dense core granules
2. α-granules
476
Platelets are essential for ?
hemostasis
477
Megakaryocytes are giant cells with multiple copies of DNA in the ____
nucleus
478
The edges of the megakaryocyte break off the form cell fragments called ?
platelets
479
What is Hemostasis?
The prevention of hemorrhage (bleeding) from a damaged vessel
480
Hemostasis is achieved through a 3-step process: ?
1. Vasoconstriction
2. Platelets aggregate into loose platelet plug
3. Clot: reinforced platelet plug (coagulation)
481
________ contributes to hemostasis by closing the vessel and preventing blood flow to the damaged region
Vasoconstriction
482
Vasoconstriction in hemostasis can be triggered by direct _____ to vascular smooth muscle, the release of _______ signals from damaged endothelial cells (endothelin) or _______ (serotonin, thromboxane A2)
injury, paracrine, platelets
483
Vasoconstriction brings down the _____ within the vessel so a secure mechanical seal can be applied in the form of a ?
pressure, clot
484
Exposed _____ binds and activates platelets
collagen
485
Inactivated platelets do not adhere to themselves or to the intact ? that line the vessel, but they contain cell surface receptors called ?
endothelium cells, integrins
486
A breach of the endothelium exposes the integrins of _______ to ______, fibronectin and laminin, which are all part of the _______ layer causing them to bind
platelets, collagen, subendothelial
487
Intact endothelial cells release substances to prevent activated platelets from binding, which includes _____ and ?
prostacyclin, nitric oxide (NO)
488
In platelet plug formation, the binding of integrins causes the activation of an ? in platelets causing them to release the contents of their _______
intracellular signaling pathway, granules
489
What are the granule contents in platelets?
serotonin (vasoconstrictor)
ADP
platelet-activating factor
490
PAF signals platelets to release ?, and activates more _____
thromboxane A2 (vasoconstrictor), platelets
491
Platelet extends many finger-like _____
filopodia
492
When ADP, serotonin and thromboxane A2 are released, they all activate additional platelets causing them to ?
recruit to the site and aggregate
493
The von Willebrand factor causes ?
platelets to form molecular bridges between one another
494
Order these statements according to platelet plug formation:
1. Platelets aggregate into platelet plug
2. Factors attract more platelets
3. Exposed collagen binds and activate platelets
4. Release of platelet factors
3, 4, 2, 1
495
Coagulation is an _______ pathway
extrinsic
496
What is an extrinsic pathway?
Another cascade of protease reactions occurring outside the vascular system
497
In coagulation, subendothelial cells express a membrane protein known as ?, which is a receptor for a plasma protein: ?When it leaves the vessel through _____ region and comes into contact with tissue factor its converted (non-proteolytically) to factor ____
tissue factor, factor VII, damaged, VIIa
498
Factor VIIa and Ca2+ form a complex that proteolytically ____ factor X to produce factor ___, which is produced from either the ______ or ______ pathway is important for the ?
cleaves, Xa, intrinsic, extrinsic, common pathway
499
Factor Xa produced from the intrinsic and extrinsic pathway join together with factor Va and Ca2+ to create ?
prothrombinase
500
Prothrombinase converts prothrombin to ______, which is a central protease of the ?
thrombin, coagulation cascade
501
Fibrinogen is then cleaved by _____ to fibrin monomers, which spontaneously polymerize to form a ? that weaves through plug and traps ?
thrombin, gel of fibrin polymers, blood cells
502
Thrombin also activates factor _____ to _____ which assists in forming the fibrin polymers into a ?
XIII to XIIIa, stable fibrin mesh
503
The intrinsic pathway is by ______ ______, whereas the extrinsic pathway is by ____ _____
contact activation, cell injury
504
? : factor XII is activated when contacting exposed collagen, activated platelets.
Final product is factor Xa
Intrinsic pathway (surface contact pathway)
505
? : factor VII leaves vessel and binds to tissue factor receptor and become activated Factor VIIa.
Final product is factor Xa
Extrinsic pathway (cell injury pathway)
506
? : factor Xa from intrinsic and extrinsic is used to create thrombin which ultimately converts fibrinogen to a stable fibrin clot
Common pathway
507
_______ is a name given to several diseases in which one of the factors in the coagulation cascade is defective or lacking
hemophilia
508
What are the common symptoms of hemophilia?
Bruise easily, spontaneous bleeding, bleeding in the joints and muscles can be painful and disabling and if bleeding occurs in the brain it can be fatal
509
What is hemophilia A?
A factor VIII deficiency
Most common ~80% of cases
510
What is hemophilia B?
Factor IX deficiency
511
Both hemophilia A and B are ?
X-linked recessive
512
What is hemophilia treated with?
with synthetic factors
513
Endothelial cells also produce a variety of anticoagulant factors that interfere with the ?
clotting cascade
514
What is a TFPI? And what are 4 examples?
Tissue Factor Pathway Inhibitor
Antithrombin III, thrombomodulin, protein S and C
515
What is fibrinolysis?
Breakdown of blood clots
516
Fibrinolysis begins with the conversion of _______ (produced in liver) to ____ through proteolysis. Endothelial cells produce tissue _____ activator (t-PA) that causes this conversion. Plasmin is capable of breaking down both ? as well as ______
plasminogen, plasmin, plasminogen, stable fibrin, fibrinogen
