Week 2 Flashcards
(225 cards)
1
Q
Compare the movement of Na+ and K+ excluding the known, Na+ moves in and K+ moves out
A
- Permeability for K+ is 50-100 times greater
- Na+ cannot move in as fast as K+ moves out
- Na+/K+ pump moves Na+ as fast as it leaks in
2
Q
What one major difference between cardiac action potentials and muscle action potentials?
A
Cardiac does not have a hyperpolarization state
3
Q
All cardiac cells have __________ resting membrane potential.
A
All cardiac cells have unstable resting membrane potential
4
Q
What anatomic component of cardiac muscle ensures the muscle beats as a syncytium?
A
Gap junctions: electrical connections between cells
5
Q
Which has the longest action potential among the three:
- Skeletal muscle
- Neuron
- Cardiac cell
A
Cardiac cell: 300+ msec
6
Q
T/F: The action potential for atrium, ventricles, and nodes are all different
A
False, cardiac muscle (atria & ventricles) have the same action potential while nodal tissue has different action potential
7
Q
Describe the action potential phases of cardiac muscle
A
Phase 0: Rapid depolarization
Phase 1: Early repolarization
Phase 2: Plateau
Phase 3: Late Repolarization
Phase 4: Resting membrane potential
8
Q
Cardiac Action Potential: what ion is responsible for plateau phase? How does it work?
A
- Ca+ coming inward via L type calcium channels
- The incoming Ca+ balances the forming negative charged caused by the efflux of K+
9
Q
Cardiac AP: During phase ___: ____________, Ca+ comes into the cell via __-type Calcium channels. Where does the Calcium come from?
A
During phase 2: Plateau, Ca+ comes into the cell via L-type calcium channels.
Calcium is coming from the T tubules since L-type Calcium channels = Dihydropyridine Receptor
10
Q
List 5 drugs that bind to DHPR receptors. What do they block?
A
- Nitrendipine
- Nimodipine
- Nifedipine
- Diltiazem
- Verapamil
Blocks calcium from entering cardiac cells via L-type Ca channels
11
Q
What can be said about the relationship between electrical and mechanical events in the cardiac said
A
Electrical events precede mechanical events or contraction follows action potential
12
Q
Describe calcium induced calcium release
A
After action potential reaches T tubule the voltage sensitive Dihydropyridine (DHP) receptors (L-type calcium channels) open for calcium entry
- Calcium influx triggers sarcoplasmic reticulum via Ryanodine Receptors to release Ca+ & increase Ca concentration
13
Q
T/F: The SR in Cardiac muscle can release enough Ca to sustain a contraction
A
False, without the calcium from the T tubules, the strength of cardiac muscle contraction would be reduced considerably because the SR of cardiac muscle is less well developed than skeletal muscle & does not store enough calcium to provide full contraction
14
Q
What characteristics of Cardiac muscle allows for large calcium stores?
A
- T tubules have diameter 5 times greater than skeletal muscle
- Large quantity of mucopolysaccharides that are negatively charged and bind an abundant store of Ca ions
15
Q
Compare the release of Ca in skeletal muscle vs cardiac muscle
A
- Skeletal: Ca+ is largely released from the SR RYR channels inside the skeletal muscle fiber
- Cardiac: Ca+ comes from stores in the T tubule in the extracellular fluid
16
Q
The _______________ of contraction of cardiac muscle depends on the concentration of calcium ions in the ECF.
A
Strength of contraction of cardiac muscle depends on [Ca]
17
Q
Contrast the coupling of cardiac vs skeletal muscle
A
- Cardiac: electrochemial coupling due too Ca induced release of Ca
- Skeletal: electromechanical coupling-direct interactions b/t the DHPR in T tubule and RYR in SR
- In cardiac, the DHPR & RYR do not touch
18
Q
Briefly describe the pathway and product for Gq proteins
A
G q > Phospholipase C > PIP2 > either DAG or IP3
DAG > Protein Kinase C > Increase Ca
IP3 > Increase Ca
19
Q
Briefly describe the pathway and products of Gs proteins
A
Gs > Adenylate cyclase > cAMP > Protein Kinase A > Inc. Ca+
20
Q
Briefly describe Gi pathway and products
A
Gi inhibits overall > Adenylate cycles > cAMP > Protein kinase A > Decreased Ca+
21
Q
Where do potassium channel blockers exert the greatest effect in cardiac muscle contraction
A
- In phase 3
- Prolongs the phase = delays repolarization
22
Q
Why does hyperkalemia shorten phases 2 & 3 despite the concentration gradient pushing K+ into the cell?
A
- Hyperkalemia increases potassium channel conductance creating excess repolarization reserve
23
Q
What phases comprise cardiac absolute refractory period?
A
Phases 1, 2 & 3 are absolute refractory period
24
Q
Cardiac muscle: Phases 1, 2, & 3 are considered the ____________ ______________ _______________ since no stimulus can generate another action potential here. Describe what enables this.
A
- Phases 1, 2, & 3 are absolute refractory period
- The Na+ channels are closed and unavailable since the inactivation gates are closed
25
Cardiac muscle: what is the effective refractory period?
What phases of the AP are considered the ERP?
- A conducted AP cnnot be generated as in there is an inward current, but not enough to conduct to the next site
- Phases 1, 2, 3, & 4
26
Cardiac muscle: what is the relative refractory period?
- Can induce a small AP but requires a larger than normal stimulus
- Na+ channels closed but are available
27
What is the supranormal period?
- State of increased excitability in cardiac muscle
- Begins -70 mV and continues until -85 mV
- Na+ channels recovered
28
T/F: Premature contractions of cardiac muscle do not cause wave summation, as occurs in skeletal muscle
True
29
What is Rhythmical Excition of the Heart?
Conduction of the nodal tissue of the heart, i.e. SA, AV node
30
What is the rate of impulse conduction in the SA Node?
60-100 BPM
31
What is the rate of impulse conduction of AV node?
40-60 Beats per minute
32
What is the rate of impulse conduction in the bundle of His AKA
- aka R & L bundle branches
- 20-40 BPM
33
What is the rate of impulse conduction in Purkinje fibers?
<20 BPM
34
Describe the action potential at the sinus node
Starts at phase 4 > Phase 0 > Phase 3
RMP > Rapid Depolarization > Late repolarization
35
Describe the action potential of the sinus node
- RMP: -55 to -60 mV as Na+ constantly leaks out
- -40 mV, slow Calcium channels (T-type) open = AP & subsequently L-type calcium channels open
- After 100-150 msec, Calcium channels close and K+ channels open to repolarize
36
T/F: Cardiac muscles have L-type calcium channels while nodal tissue has T-type calcium channels
- False, cardiac muscle only has L-type
- Nodal tissue has both T-type and L-type
37
What property of SA & AV nodes makes their tissue slow conducting?
Fast voltage-gated Na+ channels are permanently inactivated b/c less negative resting potential in the cell
38
What does the rising slope in phase 4 of the SA node determine?
Determines HR
39
What allows for the automaticity of SA & AV Nodes
Mixed Na+/K+ inward current by funny current channels cause slow spontaneous diastolic depolarization
40
What are some examples catecholamines?
Norepinephrine
Epinephrine
41
What are the parasympathetic and sympathetic receptors on the nodal tissue in the heart?
M2-parasympathetic
β1-sympathetic
42
What mechanism increases heart rate with SNS stimulation?
Sympathetic stimulation increases the chance that funny channels are open & inc. HR
43
Which branch of the ANS system changes the force of heart contraction?
Sympathetic increases force of contraction of heart as well as increasing HR
44
What phase is changed in nodal tissue AP when there is increased HR?
Phase 4 shortens which accelerates self-excitation to increase HR
45
Changes to cAMP levels in the nodal tissue do what?
Increase cAMP = increase funny current, Decrease cAMP = decrease funny current
46
How long is the delay at the AV node?
0.09 seconds
47
How long is the delay at the AV bundle?
0.04 seconds
48
Trace the path impulse flow from the atria to ventricles
Start: SA node travels through 3 inter nodal tracts to
AV node-delayed here
Travel to AV bundle - delayed here
Travel to L & R bundle branches
_Off the SA node to the L atria is Bachmann’s bundle_
49
Which has a greater delay the AV bundle or AV node?
AV node has greater delay 0.09 seconds
50
List the nodal tissue in order from _fastest_ to _slowest_ impulse conduction speed
Fastest: Purkinje system
Atria
Ventricle
AV node - slowest
51
What is the difference between rate of impulse control and speed of impulse control
- Rate of Impulse Control: Beats per minute
- Speed of Impulse Control: speed at which depolarized waves spread across myocardial cells
52
What physiological component makes the Purkinje system the fastest speed impulse conduction?
Many gap junctions at intercalated disks allow the electrical signal to travel
53
What mechanism ensure adequate blood ejection from the ventricle?
Rapid conduction through Purkinje fibers ensures adequate ejection from ventricle
54
What mechanism ensures adequate ventricular filling?
AV delay: slow conduction through AV node ensures adequate ventricular filling
55
The _____________ the potential difference between the depolarized and polarized regions (i.e., the __________ the AP amplitude), the ____________ effectively local stimuli can depolarize adjacent parts of the membrane ,and the more ____________ the wave of depolarization is propagated down the fiber.
This applies to:
Fast-response fibers: The greater the potential difference between the depolarized and polarized regions (i.e., the greater the AP amplitude), the more effectively local stimuli can depolarize adjacent parts of the membrane, and the more rapidly the wave of depolarization is propagated down the fiber.
56
Conduction velocity is dependent on:
- Fast response fibers:
- Slow response fibers:
- Conduction velocity is dependent on rate of depolarization
- Fast response: Na+ entry
- Slow response: Ca+ entry
57
What are dromotropic effects?
Changes in conduction velocity
58
AV Node Tissue: Describe how the SNS changes dromotropic effect and through what mechanism
Sympathetic Syst: has positive dromotropic effect in that it increases conduction velocity in AV node
- Increase Ca+ such that the depolarization phase is faster = inc. conduction velocity
59
AV Node Tissue: Explain how the parasympathetic NS effects the dromotropic effects and through what mechanism
- PNS: Decreased dromotropic effect = reduce conduction velocity = Reduce HR
- Decreased Ca+ = decreased depolarization
- Increased K+ outward current
60
What is the basic premise of heart block?
If conduction velocity through the AV node is slowed sufficiently, some action potentials may not be conducted at all from atria to ventricles
- Milder forms, conduction of AP from atria to ventricle are slowed
61
What is Stokes-Adams syndrome?
Delay in pickup of the heartbeat with complete AV block in AV node or bundle
- Transient (5-20 sec) of lack of blood to brain due to the delay in heartbeats leads to syncope
- 3rd degree Heart block
62
What is Ectopic pacemaker?
If AP does not surpass SA node, the AV node will pick up transmission, if AV node is blocked, AB bundle can take over, if that fails Purkinje fibers take over but a lower rate
63
The motions of the vertebrae are described how:
The motions of the vertebra are described in relation to the vertebrae immediately inferior to it
- Ex. With L1-L2 vertebral until, the **action of L1 is described** in terms of its **behavior to L2**
64
Which Lumbar vertebrae is wedge shaped?
What is the purpose of this?
- L5 Wedge shaped
- Allows for transition from vertical vertebrae to near horizontal sacrum
65
What is the action long restrictor muscles of the lumbar region?
List restrictor muscles
- Create side bending
- Erector spinae
- Quadratus lumborum
- Psoas
66
List short restrictors of the lumbar spine
- Intertransversarii
- Multifidus
- Rotatores
- Interspinales
67
Define Spondylosis
Degenerative change of the vertebral body
68
Term: ______________
Definition: Degenerative change in vertebral body
Spondylosis
69
Define Spondylolysis
Fx of the pars interarticularis
70
Term: ______________
Definition: Fracture of pars interarticularis
Spondylolysis
71
Define: Spondylolisthesis
Forward slip of one vertebrae relative to another
72
Term: _________________
Define: forward slip of one vertebrae relative to another
Spondylolisthesis
73
In XR, what does it mean if you can see the Scottie’s collar?
Indicates Fx of Pars interarticularis = Spondylolysis
74
Describe compression fx
Loss of vertebral body height
- does not have to occur from a fall
- Localized pinpoint pain
75
How is scoliosis named?
Named for **convexity side of curve** in the coronal plane
76
What is the difference between functional or structural scoliotic curve?
Functional: Curve will change its appearance with sidebending **into the convexity of the curve**
Structural: will NOT change in appearance with side bending
77
What is functional scoliosis usually caused by?
Functional curve is usually secondary to primary Fryette Type I somatic dysfunction locally (which is often caused by a Type II) or adaptation from mechanical dysfunction elsewhere
78
What is the Cobb angle used for?
Used to quantify the magnitude of spinal deformities
I.e. scoliosis, kyphosis, lordosis
79
A lateral lumbar disc buldge typically affects:
Lateral lumbar disc bulge affects the nerve root below
- L4 post. Lateral protrusion would affect L5 nerve root
80
Define: Dextroscoliosis
Scoliosis is named for convexity side of the curve
- Spine bent to the right
81
Define: Levoscoliosis
- Scoliosis is named from the convexity side for the curve
- Scoliosis where spine is sidebent left
82
What innervates the pericardium?
Phrenic nerve
83
The distribution of blood circulating to the different regions of the body is determined by:
- Output of the L ventricle
- Contractile state of the resistance vessels
84
What is purpose of Mean Arteriole Pressure?
Pressure required for blood to move forward
85
Which of the vessels in the body has the greatest resistance?
Arterioles
86
Compare the larger arteries and aorta to the arterioles
- Aorta & Large Arteries: have more elastic tissue gives them better elastic recoil
- Arterioles: have more smooth muscle than elastic tissue which makes them better resistance vessels
87
The resistance to blood flow and pressure drop in the arterial system are greatest at the:
Resistance to blood flow and pressure drop in the arterial system are greatest at the level of small arteries and arterioles
88
What are the receptors found in arterioles?
- α1 adrenergic receptors of vascular smooth muscle
- β2 adrenergic receptors found in arterioles of skeletal muscle
89
Which receptor(s) does Norepinephrine _not_ act on?
Norepi does not act on β2 receptors
90
What receptors are found in the heart? What are their actions?
- SNS: β1 to increase HR & force of contraction
- PNS: M2 to decrease HR via nodal tissue
91
Describe the parameters of a Type 1 dysfunction
- In a neutral dysfunction, sidebending and rotation occur in **opposite** directions to one another
92
Describe a Type 2 Dysfunction
In a flexed or extended dysfunction, sidebending and rotation occur in the **same** direction as one another
93
Consider the rule of threes: when palpating T_-T___, the tip of the spinous process is located one level below the transverse process of the same vertebrae
T7-T9
94
Rule of 3s: when palpating T___-T__ & T___ the spinous process is located 1/2 step below the transverse process of the same vertebrae
T4-T6 & T11
95
Rule of 3s: which of the thoracic vertebrae are the spinous process located at the _same_ level as the transverse process
T1-T3 & T12 spinous process are located at the same level as their respective transverse processes
96
Describe the superior cervical facet orientation
- Backward
- Upward
- Medial
97
Describe the orientation of the superior thoracic facets
- Backward
- Upward
- Medial
98
Describe the orientation of superior facets of the Lumbar vertebrae
Backward and Medial
99
About how much of the blood is located in the veins?
60%
100
What portion of the cardiovascular system operates in series?
What portion of the CV system operates in parallel?
- L & R Heart operate in _SERIES_
- Circulatory system operate in _PARALLEL_
101
What is cardiac output?
Rate at which blood is pumped from either ventricle
102
What factors determine cardiac output?
Heart Rate
Myocardial contractility
Preload (End diastolic P)
Afterload
103
What is preload?
- Volume of blood in the ventricles before the heart begins contraction
- Volume at end of diastole
- Volume of blood at end of ventricular filling
104
What is afterload?
Force heart must pump against for blood to move in the forward direction through the aorta
105
What is the overall flow in circulation of an adult?
What can this be equated to?
5 L/min = cardiac output
106
What are the determinants of blood flow?
Q = ΔP/R
- Q = flow
- P = pressure (P1 @ arterial end - P2 @ venous end)
- R = resistance of vessel
107
When the flow of blood is silent, what type of flow is existing in the vessel?
Laminar flow is silent
108
What is the difference in a murmur and bruit?
Mumur: turbulent blood flow heard in the _heart_
Bruit: turbulent blood flow heard in the _peripheral vasculature_
109
What is a thrill?
Palpable murmur
110
The mitral area is the best place to hear:
Mitral area is best place to hear S1 sound
111
___ sound is best heart at the left upper sternal border
S2 sound best heard at left upper sternal border
112
T/F: S3 & S4 sounds are all abnormal
False, in children and pregnant adults S3 sound can be considered normal
113
_____ sound is best heart at apex of heart with patient in the left lateral decubitus position
S3 sound
114
What is S3 sound?
Rapid ventricular filling in early diastole
115
What is S4 sound?
Turbulent flow due to stiff L ventricle/ventricular non-compliance. Atrium refuses to relax
116
____ sound is best heard at apex of heart with patient in left lateral decubitus position
S4
117
What factors determine resistance?
- Blood flow
118
T/F: There are two ways to determine resistance of blood vessels
True,
Resistance = P1-P2/Q
- Q is flow
Resistance = 8*n*L / 3.14 * r 4
- L is length of vessel
- r is radius
- n is viscosity
119
How might polycythemia impact vascular resistance?
- Polycythemia = too many RBC = increased Hct = increased viscosity
- Resistance = 8*n*L / 3.14 * r 4
- Increasing n will increase numerator and increase resistance of blood vessels
120
What is vascular conductance?
How is it calculated?
- A measure of the blood flow through a vessel for a given pressure difference
- Conductance = 1/resistance
121
What parameter change is vessel conductance the most sensitive to?
What is the equation to determine conductance?
1. Conductance is very sensitive to change in diameter of vessel
2. Conductance = 1/ Resistance
122
What controls flow of blood back to the heart?
Veins
123
What is diastolic blood pressure?
- 80 mm Hg
- Pressure of the blood in the _vessels_ during diastole
124
What is systolic blood pressure?
- 120 mm Hg
- Pressure generated during systole
125
Define: incisura
Backflow of blood to close aortic valve
126
What is mean arterial pressure?
Where is its greatest influence in the body?
- Average pressure during a complete cycle
- MAP is the driving force for blood flow to organs and capillaries
127
What is the equation(s) for MAP?
- Diastolic P + 1/3 Pulse pressure = MAP
- 1/2 Systolic BP + 2/3 Diastolic BP
128
What is pulse pressure?
Difference between systolic and diastolic pressures
129
What is pulse pressure?
Difference between systolic and diastolic pressures
130
What is vascular distensibility?
- Fractional increase in volume for each mmHg rise in pressure
- Vascular distensibility = inc in volume / inc. in pressure * original volume
131
What is vascular compliance?
What vascular capacitance?
They are the same both meaning the total quantity of blood that can be stored in a given portion of the circulation for each mm Hg
132
Compare the capacitance of veins vs arteries.
Compare the vascular distensibility of veins vs. arteries
- Capacitance of veins is 24 times larger than arteries
- Distensibility is 8 times more in veins compared to arteries
133
Compare vascular conductance vs Vascular compliance
- **Conductance**: reflection of vascular tone in situations where changes in tone lead to primarily to changes in flow
- **Compliance**: ability of vessel to respond to an increase in pressure by distend, hold an amount of blood with pressure changes
134
What causes arterial pressure increase in older adults?
The arterial walls become stiffer, less distensible = less compliant
135
What happens in veins are constricted?
When veins are constricted large quantities of blood are transferred to the heart to increase end diastolic volume/increase preload thereby increasing cardiac output
136
Compliance measures the ____________ change elicited by a ____________ change.
Elastance measures the _____________ change elicted by a _____________ change.
Compliance measures the volume change elicited by a pressure change
Elastance measures the pressure change elicited by a volume change
137
The degree of damping is proportional to:
The degree of damping is proportional to the resistance of small vessels and arterioles and the compliance of larger vessels
138
Term:
Definition: the change in arterial pressure that occurs when a stroke volume is ejected from the left ventricle into the aorta
Pulse pressure
139
What physiologic conditions can alter pulse pressure?
Arteriosclerosis & Aortic stenosis
140
Pulse pressure is directly proportional to:
Pulse pressure is directly proportional to stroke volume and arterial compliance
141
Why does arteriosclerosis have different effects on pulse pressure curve compared to aortic stenosis?
- Arterioles: the ejection of a stroke vol. from the L ventricle causes a much greater change in arterial pressure
- Aortic stenosis: lumen of aorta reduced due to stenosis of the valve. Stroke volume is reduced so less blood is ejected = lowered systolic BP, Pulse pressure, and mean pressure
142
What is aortic stenosis?
Condition associated with diameter of aortic valve opening is reduced and flow of blood through aortic valve is low. Decreased stroke volume
143
Describe the pressure pulse curve in patent ductus arteriosus?
Blood shunts from the pulmonary artery to the aorta, this causes low diastolic pressure and high systolic pressure = high pulse pressure since PP is directly proportional to stroke volume
144
How does Aortic Regurgitation change pulse pressure contours?
- In aortic regurgitation, there is back flow of blood through the aortic valve.
- Results in low diastolic and high systolic pressure leading to high pulse pressure
145
What is right atrial pressure?
- R atrial pressure = Central venous pressure
- Normally, 0 mmHg
146
Describe the relationship that establishes central venous pressure
- Right atrial pressure is regulated by a balance between the ability of the heart to pump blood out of the atrium and the rate of blood flowing into the atrium from the peripheral veins
147
Weight of blood in the vessels causes venous pressure to be as high as 90 mmHg. What lowers venous pressure?
Venous pump maintains low venous pressure in legs
148
Why is atrial repolarizing not seen on an EKG?
Atrial repolarization is hidden by the QRS complex meaning, it is hidden by ventricular depolarization
149
What happens to the P wave if cell conduction decreases?
If conduction decreases in the atria, the P wave will become more spread out
150
What does the PR segment represent?
- Time of conduction through the AV node
- Time from first depolarization of the atria to first depolarization of the ventricles
151
Why is the QRS complex total duration similar to the duration of the P wave?
- The conduction velocity of the Purkinje system is much faster than atrial conducting system
152
What does the ST segment represent?
Changes to this segment may indicate:
1. ST segment is early part of ventricular repolarization
2. Myocardial ischemia or injury
153
What is a normal PR interval?
0.12-0.20 seconds
154
What is a normal QRS interval?
0.06-0.11 seconds
155
What is a normal QT interval?
0.36 to 0.44 seconds
156
What are three things a EKG needs to be considered normal?
- P wave must come _before_ the QRS complex
- Rate is 60-100 BPM
- RR internal must be regular
157
What is the time duration for a large box on EKG paper?
On what axis?
Time for large box is 0.20 seconds
Tims is on the X axis
158
What is the voltage of one large box on EKG paper?
On what axis?
- Voltage is 0.5 mV
- Read on Y axis
159
T/F: No potential is recorded when the ventricular muscle is either completely depolarized or repolarized?
True
160
Where is the ____________ lead aVR located?
Augmented lead aVR is on right arm
161
Where is __________ lead aVL located?
Augmented lead aVL is located on Left arm
162
Where is ____________ lead aVF located?
Augmented lead aVF is located on Left foot
163
These leads measure vectors towards or away from the apex of the heart:
Inferior leads- II, III, aVF
164
What do the inferior leads II, III, aVF measure?
Measure vectors towards or away from the apex
165
What do the lateral leads I, aVL, V5, and V6 measure ?
Vectors towards or away from the L ventricular free wall
166
The following leads measure vectors towards or way from the left ventricular free wall
Lateral leads I, aVL, V5, V6
167
What do Right sided leads aVR, V1 measure?
Measure vectors towards or away from the right side
168
The following leads measure vectors towards or away from the right side
Right sided lead aVR, V1
169
What do anterior V2, V3, V4 leads measure?
Measure vectors towards or away from the right side
170
What do anterior leads V2, V3, V4 measure?
Measures vectors in front and back of the heart
171
The following leads measure vectors in front and back of the heart
Anterior-V2, V3, V4
172
What is the direction of charge for all bipolar limb leads?
Give examples of a bipolar limb lead
Always from Negative to Positive
- Lead I
- Lead II
- Lead II
173
What does the bulbus cordis give rise to?
Smooth portion of L & R ventricle
174
Truncus arteriosus becomes:
Aortic arch & pulmonary trunk
175
What is Truncus arteriosis?
Aorta and pulmonary artery do not separate and allows mixing of blood
176
What causes Transposition of the Great Vessels? What is it?
- Caused by lack of spiraling of truncus arteriosus
- Right ventricle attached to aorta & L ventricle attached to pulmonary A
- consistently getting deoxygenated blood
177
Persistent Truncus Arteriosis is associated with what condition?
- DiGeorge Syndrome
178
Describe the formation of the atria
1. Septum primum forms
2. Septum secundum forms proximal to the endocardial cushion
3. Hole in both primum & septum = foramen ovale
179
What is the difference between patent foramen ovale and Atrial septal defect?
- Patent ovale is incomplete joining of septum primum & septum secundum forms that can be asymptomatic if there is not enough pressure to open the foramen
- Atrial septal defect is persistent shunt b/t R & L atrium
180
What is the most common atrial septal defect?
Defect in septum secundum
181
Where does the aortic arch come from?
- From mesoderm & neural crest cells
182
What germ layer gives rise to the primordial heart
Splanchnic mesoderm in 3rd week of gastrulation
183
List the 5 heart tube dilations from venous to arterial end
1. Sinus venosus
2. Primitive atrium
3. Primitive ventricle
4. Bulbus cordis
5. Truncus arteriosus
184
If a question asks about septum primum and septum secundum, what structure are they asking about?
Formation of the atria
185
Which fetal vascular structure shunts blood from the pulmonary artery to the aorta bypassing the lungs
Ductus arteriosus
186
Which fetal vascular structure shunts blood away from the liver?
Ductus venosus
187
What does the umbilical vein become postnatally?
Ligamentum teres hepatis
AKA Round ligament of the liver
188
_____________ _____________ from the lateral plate __________ in the cephalic area forms the primordium of the heart.
Splanchnic mesoderm from the lateral plate mesoderm in the cephalic area forms the primordium of the heart.
189
What structures form the two heart tubes?
- Endothelial strands (angioblastic cords) in cardiogenic mesoderm are the earliest sign of the heart
- These tubes will canalize to form two heart tubes
190
What folding moves the heart to the thoracic region rather than being the most cranial structrure?
Caudal cranial foling
191
List the three sets of veins that dump into the sinus venosus
Vitelline
Umbilical vein
Common cardinal
192
What do vitelline veins do?
Return poorly oxygenated blood from yolk sac/umbilical vesicle
193
What do umbilical veins do?
What is a special component of these veins?
- Carry oxygenated blood to embryo from placenta
- Includes the ductus venosus: bypassing the liver in circulation straight to IVC
194
What do the common cardinal veins do?
- Return poorly oxygenated blood to placenta
195
Which arteries from the pharyngeal arch degenerate?
1, 2, 5
196
Splanchnic layer is synonymous with _____________ ____________. Which came from the _____________. The Splanchnic layer gives rise to what layers of the heart?
- Splanchnic layer = visceral layer
- Came from mesoderm
- Splanchnic layer gives rise to myocardium and endocardium of the heart
197
Embryology: The mesoderm gives rise to splanchnic layer which gives rise to the myocardium and endocardium. Where does the epicardium come from?
Migrating tissue from the mesoderm gives rise to the epicardium
198
During what time period does the heart tube divide into 4 chambers?
4th - 8th week
199
What components form the AV canal?
Atria & Ventricle septum attachment is formed by endocardial cushions, cardiac jelly, and neural crest cells
200
What does the primordial pulmonary vein form?
Primordial pulmonary vein forms the L atrium smooth portion of the muscle wall
201
What is the name of the positional disorder of the heart wherein the apex is turned to the R side of the body?
T/F: It is always fatal
Dextrocardia
- False, if all the body organs are also swapped = OK
- If Isolated Dextrocardia w/sinus solitus = bad
202
What is the most common type of ventricular heart defect?
- Problem with membranous portion
203
This condition causes cyanosis at brith due to abnormal fusion of arteries and veins to atria
Transposition
204
What does the Truncus arteriosus give rise to?
Pulmonary trunk & ascending aorta
205
What happens to the ductus arteriosus after birth?
- Closes
- Becomes Ligamentum Arteriosum
206
What does the primitive ventricle give rise to?
Trabeculated part of L & R ventricle
207
What does the primitive atrium give rise to?
Trabeculated part of the R & L atrium
208
What does the sinus venosus give rise to?
Smooth part of R atrium
Coronary sinus
Oblique vein of L atrium
209
Define patent:
Open or unobstructed aperture
210
Lift 5 key elements of a normal mid-trimester four chamber view
1. Heart area no more than 1/3 of chest area
2. R & L sided structures are approximately equal
3. Patent foramen ovale
4. Intact cardiac ‘crux’ with normal AV valves and ventricular septum
5. R Ventricle identified by presence of moderator band
211
What is dextrocardia with siuts inversus
- Heart apex is positioned R and the rest of the organs are also switched
212
What is the most common type of congenital heart disease?
Ventricular septal defects
213
What is muscular VSD
- Less common form of Ventricular septal defect
- Hole in ventricle in any portion or part of the ventricle
214
What is Tetralogy of Fallot?
- Congenital heart defect
1. Pulmonary stenosis
2. R ventricular hypertorphy
3. Overriding aorta
4. Ventricular septal defect
215
What do the third pair of pharyngeal arches give rise to?
- Proximal part forms common carotid
- Internal carotid
216
What do the third pair of pharyngeal arches give rise to?
- Proximal part forms common carotid
- Internal carotid
217
What do the fourth pair of pharyngeal arches give rise to?
- Portion of Aortic arch
- Right subclavian A
218
What do the 6th pair of pharyngeal arches give rise to?
- L pulmonary A
- R pulmonary A
- Distal portion of the Right pharyngeal arch disappears
219
What is coarctation of the aorta?
- It is a narrowing in the aorta either before or after the ductus arteriosus
- Forces the heart to work harder
- Weak femoral pulse
- Differential blood pressure b/t upper and lower extremities
220
What forms the fossa ovalis floor? What forms the border of the fossa ovalis?
Floor formed by septum primum
Edge: Septum secundum
221
What is the time period of ductus arteriosus functional and anatomic closure?
Functional closure: first few days after birth
Anatomic: by 12th week
222
_____natally you want a patent foramen ovalis.
_________ you _do not_ want a patent ductus arteriosus.
- Prenatally you want a patent foramen ovalis.
- Postnatally you _do not_ want a patent ductus arteriosus.
223
Describe the motor weakness, screening examination, & reflexes for lumbar disc herniation of L4
- Motor: Extension of quadriceps
- Screening examination: Squat and rise
- Reflexes: Knee jerk diminished
224
Name the motor weakness, screening examination, and reflexes associated with lumbar disc herniation of L5
- Motor: dorsiflexion of great toe and foot
- Screening examination: Heel walking
- Reflex: None reliable
225
List the motor weakness, screening examination and reflexes associated with S1 lumbar disc herniation
- Motor weakness: Plantar flexion of great toe and foot
- Screening examination: Walking on toes
- Reflexes: Ankle jerk diminished
