Cardio Physiology (REYNOLDS) Flashcards
1
Q
Discuss periodontal disease and heart health:
A
- Studies suggest the toothbrush as a weapon against heart attacks, strokes and other heart disease conditions
- Studies suggest that oral health, and gum disease in particular, are related to serious conditions like heart disease
- People with periodontal disease are almost twice as likely to have coronary artery disease
2
Q
(T/F)
People with periodontal disease are almost twice as likely to have coronary artery disease.
A
True
3
Q
How long do you have to wait for dental tx after a heart attack?
A
6 months for extensive dental tx
note: you dont need to wait to have a dental cleaning
4
Q
Which of the followng is Myocardium?
A
The one on the left
5
Q
A
6
Q
Which of the following impact the rate of heart contractions?
A. Hypertrophy
B. Inotropy
C. Chronotropy
D. Dromotropy
A
C. Chronotropy
Inotropy = force of heart contractions
Chronotropy = rate of heart contractions
Dromotropy = conduction velocity
7
Q
Which of the following impact the force of heart contractions?
A. Hypertrophy
B. Inotropy
C. Chronotropy
D. Dromotropy
A
B. Inotropy
Inotropy = force of heart contractions
Chronotropy = rate of heart contractions
Dromotropy = conduction velocity
8
Q
Which of the following impact the conduction velocity of heart contractions?
A. Hypertrophy
B. Inotropy
C. Chronotropy
D. Dromotropy
A
D. Dromotropy
Inotropy = force of heart contractions
Chronotropy = rate of heart contractions
Dromotropy = conduction velocity
9
Q
Which of the following refers to abnormal rhythm?
A. Tachycardia
B. Bradycardia
C. Arrhythmia
D. Dysrhythmia
A
D. Dysrhythmia
Arrhythmia = NO rhythm
Dysrhythmia = Abnormal rhythm
10
Q
What are the two types of cardiac muscle cells?
- Which one controls and coordinates heartbeat?
- Which one produces contractions that propel blood?
A
Conducting system cells: controls and coordinates heartbeat
Contractile cells: produce contractions that propel blood
11
Q
What are the 5 components of the conducting system in the heart?
(list them in order of fastest firing rate to slowest)
A
- SA node:
- “pacemaker”
- in wall of right atrium
- highest firing rate
- automacity
- Internodal pathways
- AV node
* there is an important delay in AV node - AV bundles
- Bundle branches
- Purkinje fibers
12
Q
Discuss what prepotential is in regards to th conducting system of the heart:
A
Prepotential is spontaneous depolarization and is the reason why there is automacity of the heart. Bc of prepotential the heart can contract w/o neural stimulation
- ONLY found in cardiac muscle
- skeletal muscles do not have a prepotential
13
Q
Why is th SA node referred to as the pacemaker?
A. because it is the first one in the conducting system
B. has a smaller prepotential
C. has the highest rate of firing
D. All of the above
A
D. All of the above
14
Q
________ is the reason for the automacity of heart contractions.
A
Prepotential (spontaneous depolarization)
15
Q
If the SA node didn’t functin but everything else was functioning, what would the heart rate be?
A
Slower bc the heart is now relying on the AV valve
16
Q
What property does the prepotential gradient give the heart that skeletal muscle doesn’t possess?
A
Automacity- can contract w/o neural stimulation
17
Q
The cardiac cycle begins with an action potential at _______.
A. AV node
B. SA node
C. Purkinje fibers
D. AV bundle
A
B. SA node
18
Q
Which of the following is the first to contract in the cardiac cycle?
A. atria
B. ventricles
A
A. atria
note: after the atria contract, contraction will begin at the apex of the ventricles (think about squeezing toothpaste)
19
Q
Which of the following is true in regards to cardiac and skeletal muscle?
A. Only skeletal muscle has a rapid depolarization
B. Cardiac muscle has a shorter absolute refractory period
C. Cardiac muscle has a much longer refractory period
D. Skeletal muscle contraction is dictated by extracellular calcium
A
C. Cardiac muscle has a much longer refractory period
note: cardiac muscle has a much longer refractory period due to a plateau caused by L-type (slow) Ca2+ channels that are “leaky”
20
Q
What is the reason why a plateau occurs in cardiac muscle contraction?
A
L-type Ca2+ channels that are extremely slow
note: L-type Ca2+ channels are what bring extracellular Ca2+ into the cardiac muscle cells
21
Q
Which of the following is true regarding cardiac muscle cell contraction?
A. majority of the Ca2+ involved in contraction come from the sarcoplasmic reticulum (SR)
B. half of the Ca2+ involved in contraction come from the extracellular matrix (ECM)
C. half of the Ca2+ involved in contraction come from the sarcoplasmic reticulum (SR)
D. majority of the Ca2+ involved in contraction comes from the extracellular matrix (ECM)
A
D. majority of the Ca2+ involved in contraction comes from the extracellular matrix (ECM)
note: majority of the Ca2+ involved in skeletal muscle contraction comes from the SR
22
Q
Which of the following is true?
A. Skeletal muscle depends mainly on intracellular calcium sources (SR)
B. Myocardium depends mainly on extracellular calcium through L-type Ca2+ channels
C. Smooth muscle depends mainly on extracellular calcium
D. All of the above
A
D. All of the above
23
Q
Discuss the 3 steps involved in myocardium muscle contraction:
- Rapid depolarization
- The plateau
- Repolarization
A
Rapid depolarization:
- cause: Na+ entry
- duration: rapid
- ends with: closure of Na+ channels
The Plateau:
- cause: Ca2+ entry
- duration: very slow
- ends with: closure of slow calcium channels
Repolarization:
- cause: K+ loss
- duration: medium
- ends with: closure of slow K+ channels
24
Q
Why is a long absolute refractory period important in cardiac muscle contraction?
A
prevents tetany (spasms)
25
The _______ is the period between the start of one heartbeat and the beginning of the next.
Cardiac cycle
26
What are the two phases of the cardiac cycle?
Systole = contraction
Diastole = relaxation
27
Discuss the phases of the cardiac cycle in respect to the chambers and valves:
* Beginning of Atrial systole
* End of atrial systole
* 1st phase of ventricular systole
* 2nd phase of ventricular systole
* Early ventricular diastole
* Late ventricular diastole
**_Cardiac Cycle_**
## Footnote
**_Beginning of Atrial Systole:_**
* atrial contraction forces a small amount (70%) of blood into ventricles
* Ventricles are in diastole
* ALL AV valves are open
* Semilunar valves are closed
**_End of Atrial Systole:_**
* Semilunar valves remain closed
* **EDV** (end diastolic volume): ventricles are full of blood at this point
**_1st Phase of Ventricular Systole:_**
* Ventricular contraction pushes the AV valves closed ---\> **"Lub"** sound
**_2nd Phase of Ventricular Systole:_**
* As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected out of the heart
* You reach **ESV** (still a little blood in ventricles)
**Early Ventricular Diastole:**
* pressure in ventricles drops
* blood flows back against the cusps of the semilunar vales and force them closed ---\> **"Dub"** sound
* blood flows into the relaxed atria
**_Late Ventricular Diastole:_**
* All chambers are relaxed
* AV valves reopen and process starts over again
28
EDV (end-diastolic volume) refers to the maximum amount of blood in the ventricles and occurs at which of the following steps of the cardiac cycle?
A. Beginning of atrial systole
B. End of atrial systole
C. 1st phase of ventricular systole
D. 2nd phase of ventricular systole
E. Early ventricular diastole
B. End of atrial systole
29
Which of the following steps of the cardiac cycle does the "Lub" sound occur?
A. Beginning of atrial systole
B. End of atrial systole
C. 1st phase of ventricular systole
D. 2nd phase of ventricular systole
E. Early ventricular diastole
C. 1st phase of ventricular systole
note: the "Lub" sound comes from the AV valves closing
note: the "Dub" sound comes from the semilunar valves closing
30
Which of the following steps of the cardiac cycle does the "Dub" sound occur?
A. Beginning of atrial systole
B. End of atrial systole
C. 1st phase of ventricular systole
D. 2nd phase of ventricular systole
E. Early ventricular diastole
E. Early ventricular diastole
31
Which of the following steps of the cardiac cycle do we reach **ESV** (end-systolic volume)?
A. Beginning of atrial systole
B. End of atrial systole
C. 1st phase of ventricular systole
D. 2nd phase of ventricular systole
E. Early ventricular diastole
D. 2nd phase of ventricular systole
EDV = end of atrial systole
ESV = end of ventricular systole
32
All of the following are true regarding the beginning of atrial systole EXCEPT:
A. AV valves are closed
B. Semilunar valves are closed
C. AV valves open
D. Ventricles are relaxed
A. AV valves are closed
33
All of the following are true regarding the end of atrial systole EXCEPT:
A. AV valves close
B. Atrial diastole begins
C. Semilunar valves are closed
D. EDV reached
E. Semilunar valves open
E. Semilunar valves open
note: at the end of atrial systole the AV valves close making the "Lub" sound and at this point ALL VALVES ARE CLOSED
34
All of the following are true regarding the first phase of ventricular systole EXCEPT:
A. AV valves are open
B. Semilunar valves are closed
C. AV valves are closed
D. Atria are relaxed
A. AV valves are open
35
All of the following are true regarding the first phase of ventricular systole EXCEPT:
A. Semilunar valves are closed
B. Semilunar valves open
C. AV valves are closed
D. Atria are relaxed
B. Semilunar valves open
note: in the second phase of ventricular systole, ventricular pressure rises and exceeds pressure in thee arteries which pushes the semilunar valves open
36
All of the following are true regarding the second phase of ventricular systole EXCEPT:
A. Semilunar valves are closed
B. Semilunar valves open
C. AV valves are closed
D. Atria are relaxed
A. Semilunar valves are closed
37
All of the following are true regarding early ventricular diastole EXCEPT:
A. Semilunar valves closed
B. Semilunar valves open
C. AV valves are closed
D. Atria are relaxed
B. Semilunar valves open
note: as ventricles relax in early ventricular diastole, pressure in the ventricles drop; blood flows back against cusps of semilunar valves and forces them closed making the **"Dub"** sound
38
All of the following are true regarding late ventricular diastole EXCEPT:
A. Semilunar valves are closed
B. Semilunar valves open
C. AV valves open
D. Atria are relaxed
E. Ventricles are relaxed
B. Semilunar valves open
note: ALL chambers are relaxed
39
(T/F)
Blood pressure in any chamber rises during systole and falls during diastole.
True
40
(T/F)
Blood flows from low to high pressure, is controlled by timing of contractions and is directed by one-way valves.
False
Correct statement: Blood flows from **high to low** pressure, is controlled by timing of contractions and is directed by one-way valves.
41
Closing of the **semilunar valves** makes which of the following sounds?
A. "Lub"
B. "Dub"
C. "Scrub"
D. "Crud"
B. "Dub"
**AV valves = "Lub"**
**Semilunar valves = "Dub"**
42
Closing of the **AV valves** makes which of the following sounds?
A. "Lub"
B. "Dub"
C. "Scrub"
D. "Crud"
A. "Lub"
AV valves = "Lub"
Semilunar valves = "Dub"
43
Maximum ventricular volume is referred to as:
A. EDV (end-diastolic volume)
B. ESV (end-systolic volume)
C. SV (Stroke volume)
D. Ejection fraction
A. EDV (end-diastolic volume)
**EDV** = max ventricular volume
**ESV** = ventricular volume after contraction cycle
**SV** = amount pushed out of heart after contraction
**Ejection fraction** = the percentage of EDV represented by SV
44
\_\_\_\_\_\_\_\_ is the amount pushed out of the heart after contraction.
A. EDV (end-diastolic volume)
B. ESV (end-systolic volume)
C. SV (Stroke volume)
D. Ejection fraction
C. SV (Stroke volume)
**REMEMBER THIS EQUATION: SV = EDV - ESV**
**EDV** = max ventricular volume
**ESV** = ventricular volume after contraction cycle
**SV** = amount pushed out of heart after contraction
**Ejection fraction** = the percentage of EDV represented by SV
45
\_\_\_\_\_\_\_ is the perventage of EDV represented by SV.
A. EDV (end-diastolic volume)
B. ESV (end-systolic volume)
C. SV (Stroke volume)
D. Ejection fraction
D. Ejection fraction
**EDV** = max ventricular volume
**ESV** = ventricular volume after contraction cycle
**SV** = amount pushed out of heart after contraction
**Ejection fraction** = the percentage of EDV represented by SV
46
The ventricular volume after a contraction cycle is referred to as \_\_\_\_\_\_\_\_\_\_.
A. EDV (end-diastolic volume)
B. ESV (end-systolic volume)
C. SV (Stroke volume)
D. Ejection fraction
B. ESV (end-systolic volume)
**EDV** = max ventricular volume
**ESV** = ventricular volume after contraction cycle
**SV** = amount pushed out of heart after contraction
**Ejection fraction** = the percentage of EDV represented by SV
47
What is the equation for Cardiac Output (CO)?
CO = HR x SV
CO = mL/min
HR = beats/min
SV = mL/beat
Cardiac Output = Heart Rate x Stroke Volume
48
\_\_\_\_\_\_\_\_ is the volume pumped by the **left ventricle** in 1 minute.
Cardiac Output
CO = HR x SV
49
What is the equation for Stroke Volume?
SV = EDV - ESV
50
All of the following are factors effecting Cardiac Output (CO) EXCEPT:
A. Autonomic innervation
B. Hormones
C. EDV
D. ESV
E. All of the above effect cardiac output
E. All of the above effect cardiac output
Cardiac Output will decrease if you decrease heart rate or stroke volume
51
Which of the following will cause a decrease in Cardiac Output?
A. sympathetic stimulation
B. parasympathetic stimulation
B. parasympathetic stimulation
**Parasympathetic** stimulation releases **ACh**, which extends replarization and decreases the rate of spontaneous depolarization thus slowing the heart rate
**Sympathetic** stimulation releases **NE**, which shortens repolarization and accelerates the rate of spontaneous depolarization thus increasing the heart rate
52
Which of the following releases Norepinephrine (NE)?
A. Sympathetic system
B. Parasympathetic system
A. Sympathetic system
Parasympathetic stimulation releases ACh, which extends replarization and decreases the rate of spontaneous depolarization thus slowing the heart rate
Sympathetic stimulation releases NE, which shortens repolarization and accelerates the rate of spontaneous depolarization thus increasing the heart rate
53
Which of the following **shortens repolarization** and accelerates the rate of spontaneouus depolarization?
A. Acetylcholine (ACh)
B. Norepinephrine (NE)
B. Norepinephrine (NE)
note: shortening repolarization and accelerating spontaneous depolarization causes an increase in heart rate
54
All of the following are true regarding the Atrial Reflex EXCEPT:
A. also called Bainbridge reflex
B. adjusts heart rate in response to venous return
C. Stretch receptors in the right atrium
D. Causes a decrease in heart rate
E. Involved in sympathetic system
D. Causes a decrease in heart rate
note: Atrial Reflex causes an increase in heart rate
55
Which of the following has a **short preganglionic** fiber?
A. sympathetic system
B. parasympathetic system
A. sympathetic system
note: the sympathetic system has 2 lower motor neurons in the heart where Epi or NE is used
note: parasympathetic system only has one lower motor neuron
56
**Parasympathetic stimulation** has all of the following effects EXCEPT:
A. extends repolarization
B. accelerates the rate of spontaneous depolarization
C. lowers heart heart rate
D. All of the above are effects of the parasympathetic system
B. accelerates the rate of spontaneous depolarization
**_Sympathetic stimulation:_**
* shortens repolarization
* accelerates the rate of spontaneous depolarization
* increases heart rate
**_Parasympathetic stimulation:_**
* extends repolarization
* decreases the rate of spontaneous depolarization
* decreases heart rate
57
Sympathetic stimulation has all of the following effects on heart muscle EXCEPT:
A. shortens repolarization
B. accelerates the rate of spontaneous depolarization
C. increases heart rate
D. All of the above are effects of the sympathetic system
D. All of the above are effects of the sympathetic system
**_Sympathetic stimulation:_**
* shortens repolarization
* accelerates the rate of spontaneous depolarization
* increases heart rate
**_Parasympathetic stimulation:_**
* extends repolarization
* decreases the rate of spontaneous depolarization
* decreases heart rate
58
All of the following are true regarding **Atrial Reflex** EXCEPT:
A. also called Bainbridge reflex
B. adjusts the heart rate in response to venous return
C. Stretch receptors in the right atrium trigger an increase in heart rate
D. Increases sympathetic stimulation
E. All of the above are true regarding atrial reflex
E. All of the above are true regarding atrial reflex
Important note: the Atrial Reflex adjusts the heart rate in response to **venous return**
59
Discuss both the cardioaccelerator center and cardioinhibitory centers in regards to each of the following:
* Where are both of those centers located?
* Which of the following is involved in the cardioaccelerator center?
* A. Sympathetic sys
* B. Parasympathetic sys
* Which of the following travels along the Vagus nerve?
* A. Sympathetic sys
* B. Parasympathetic sys
* Which of the following synapses in the cardiac plexus?
* A. Sympathetic ganglion
* B. Parasympathetic ganglion
* Which of the following has a very short postganglionic fibers?
* A. Sympathetic sys
* B. Parasympathetic sys
* Sympathetic innervation mostly effects which of the following?
* A. SA node
* B. AV node
* Parasympathetic innervation mostly effects which of the following?
* A. SA node
* B. AV node
* Where are both of those centers located?
* medulla oblongata
* Which of the following is involved in the cardioaccelerator center?
* **A. Sympathetic sys**
* B. Parasympathetic sys
* Which of the following travels along the Vagus nerve?
* A. Sympathetic sys
* **B. Parasympathetic sys**
* Which of the following synapses in the cardiac plexus?
* A. Sympathetic ganglion
* **B. Parasympathetic ganglion**
* Which of the following has a very short postganglionic fibers?
* A. Sympathetic sys
* **B. Parasympathetic sys**
* Sympathetic innervation mostly effects which of the following?
* **A. SA node**
* B. AV node
* Parasympathetic innervation mostly effects which of the following?
* A. SA node
* **B. AV node**
**_Careful!!!_ At _REST_ the parasympathetic system mostly effects the _SA node_**
* The previous questions are when a person is NOT at rest
note: parasympathetic **post**ganglia are either extremelt close to or actually **within the target organ** which is how you can remember that the PNS has a short postganglion
note: sympathetic sys has a **short PREganglion**
60
All of the following are factors that affect **EDV** (end-diastolic volume) EXCEPT:
A. Preload
B. Filling time
C. Venous return
D. All of the above are factors that influence EDV
A. Preload
**_Factors that affect EDV:_**
* **Filling time**: duration of ventricular diastole
* **Venous return**: rate of blood flow during ventricular diastole
**_Factors that affect ESV:_**
* **Preload**: ventricular stretching during diastole
* **Contractility**: force produced during contraction, at a given preload
* **Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
61
All of the following are factors that affect **ESV** (end-systolic volume) EXCEPT:
A. Preload
B. Filling time
C. Afterload
D. Contractility
E. All of the above are factors that influence ESV
B. Filling time
**_Factors that affect EDV:_**
* **Filling time**: duration of ventricular diastole
* **Venous return**: rate of blood flow during ventricular diastole
**_Factors that affect ESV:_**
* **Preload**: ventricular stretching during diastole
* **Contractility**: force produced during contraction, at a given preload
* **Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
62
Which of the following refers to **ventricular stretching during diastole**?
A. Filling time
B. Venous return
C. Preload
D. Contractility
E. Afterload
C. Preload
**Filling time**: duration of ventricular diastole
**Venous return**: rate of blood flow during ventricular diastole
**Preload**: ventricular stretching during diastole
**Contractility**: force produced during contraction, at a given preload
**Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
63
Which of the following refers to the **tension the ventricle produces to open th semilunar valve and eject blood**?
A. Filling time
B. Venous return
C. Preload
D. Contractility
E. Afterload
E. Afterload
**Filling time**: duration of ventricular diastole
**Venous return**: rate of blood flow during ventricular diastole
**Preload**: ventricular stretching during diastole
**Contractility**: force produced during contraction, at a given preload
**Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
64
Which of the following refers to the **duration** of ventricular diastole?
## Footnote
A. Filling time
B. Venous return
C. Preload
D. Contractility
E. Afterload
A. Filling time
**Filling time**: duration of ventricular diastole
**Venous return**: rate of blood flow during ventricular diastole
**Preload**: ventricular stretching during diastole
**Contractility**: force produced during contraction, at a given preload
**Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
65
Which of the following refers to the **rate** of blood flow during ventricular diastole?
A. Filling time
B. Venous return
C. Preload
D. Contractility
E. Afterload
B. Venous return
**Filling time**: duration of ventricular diastole
**Venous return**: rate of blood flow during ventricular diastole
**Preload**: ventricular stretching during diastole
**Contractility**: force produced during contraction, at a given preload
**Afterload**: tension the ventricle produces to open the semilunar valve and eject blood
66
Which of the following is directly proportional to **EDV**?
A. Filling time
B. Venous return
C. Preload
D. Contractility
E. Afterload
C. Preload
**_Preload:_**
* the degree of ventricular stretching during ventricular diastole
* Directly proportional to EDV
* Affects ability of muscle cells to produce tension
67
Which of the following is FALSE regarding Preload?
A. The degree of ventricular stretching during ventricular diastole
B. Directly proportional to ESV
C. Affects ability of muscle cells to produce tension
D. All of the above are true
B. Directly proportional to ESV
correct statement: Preload is directly proportional to **EDV**
68
\_\_\_\_\_\_\_\_\_\_ states that the force of contraction of myocardium is directly proportional to the stretch of th muscle (preload).
Frank-Starling Law of Contraction
* this means: more blood in ventricle = more forceful contraction
* As EDV increases, stroke volume increases
* SV = EDV - ESV
69
Ventricular expansion is limited by all of the following EXCEPT:
A. myocardial connective tissue
B. the cardiac (fibrous) skeleton
C. the pericardial sac
D. All of the above limits ventricular expansion
D. All of the above limits ventricular expansion
70
Contractility of the myocardium is affect by all of the following EXCEPT:
A. Autonomic innervation
B. Hormones
C. Diet
D. All of the above affect contractility
C. Diet
71
Sympathetic stimulation have all of the following effects on contractility EXCEPT:
A. NE released by postganglionic fibers of cardiac nerves
B. Epinephrine and NE are released by the adrenal medullae
C. Causes ventricles to contract with more force
D. Decreases ejection fraction and increases ESV
E. All of the above are effects of sympathetic stimulation
D. Decreases ejection fraction and increases ESV
Correct statement: sympathetic stimulation **increases ejection fraction** and **decreases ESV**
72
In the parasympathetic system, **acetylcholine (ACh)** is releaed by which of the following?
A. adrenal medullae
B. hypothalamus
C. vagus nerves
D. All of the above
C. vagus nerves
ACh = vagus nerves
Epi and NE = adrenal medullae
73
\_\_\_\_\_\_ is **increased** by any factor that **restricts arterial blood flow**.
A. Preload
B. Contractility
C. Afterload
D. Venous return
C. Afterload
74
(T/F)
As afterload increases, stroke volume increases.
False
correct statement: as **afterload increases**, **stroke volume decreases**
**Afterload** refers to the tension the ventricles produce to open the semilunar valve and eject blood
75
Discuss what effect each of the following have on EDV or ESV and how that affects SV and CO.
* Increasing Venous return
* Increasing Filling time
* Increasing Contractility
* Increasing Afterload
**CO = HR x SV**
**SV = EDV - ESV**
**_Increasing venous return:_**
* increases EDV
* increases SV
* increases CO
**_Increasing filling time:_**
* increases EDV
* increases SV
* increases CO
**_Increasing contractility:_**
* decreases ESV
* increases SV
* increases CO
**_Increasing afterload:_**
* increases ESV
* decreases SV
* decreases CO
**_Main concept:_**
* increasing EDV = increases SV
* increasing ESV = decreases SV
76
At rest:
A. EDV is low
B. Myocardium stretches more
C. Stroke volume is high
D. All of the above
A. EDV is low
**_At rest:_**
* **EDV is low**
* Myocardium stretches less (cause theres less blood in ventricle)
* stroke volume is low (SV = EDV - ESV)
**_With Exercise:_**
* **EDV is high**
* Myocardium stretches more
* Stroke volume increases
77
(T/F)
Afterload is decreased by any factor that restricts arterial blood flow.
False
Correct Statement: Afterload is **increased** by any factor that restricts arterial bloodflow
Afterload refers to the tension produced by the ventricles to open the semilunar valve and eject blood
* Increasing afterload decreases SV by increasing ESV
* SV = EDV - ESV
78
Sympathetic stimulation has all of the following effects EXCEPT:
A. increases venous return which increases SV
B. increases filling time which increases SV
C. increases contractility which increases SV
D. increases afterload which increases SV
E. sympathetic stimulation effects all of the above
D. increases afterload which increases SV
Increasing afterload:
* increases ESV
* SV = EDV - ESV
* which in turn decreases SV as you can see in the equation above
note: if something increases EDV it is also increasing SV
note #2: if something increases ESV it decrease SV
79
Which of the following travels in close proximity to the **Endocardium**?
(select all that apply)
A. SA node
B. AV node
C. AV bundle
D. Purkinje fibers
C. AV bundle
D. Purkinje fibers
note: this a very important concept because its a way to seperate the conduction signaling from the myocardium
80
What are the 4 specialized myocytes we need to know for this exam?
1. SA node
2. AV node
3. AV bundle (bundle of His)
4. Purkinje fibers
81
All of the following are true regarding Purkinje fibers EXCEPT:
A. modified, specialized cardiac muscle cells
B. Organized into nodes and fibers
C. Generate and rapidly transmit the contractile impulse
D. All of the above are true
D. All of the above are true
82
List each of the following in order from beginning to end regarding ion channels of the myocardium.
* Na+ enters and exits the cell simultaneously
* Na+ rapidly enters cell
* K+ leaves cell as Na+ enters the cell
* Ca2+ is entering and exiting cell while K+ is exiting
* K+ exits the cell
1. Na+ rapidly enters cell = **rapid depolarization**
2. K+ exits the cell = partial repolarization
3. Ca2+ is entering and exiting cell (leakyness) while K+ is exiting = **Plateau**
4. K+ leaves the cell as Na+ enters the cell
5. Na+ is entering and exiting the cell
83
All of the following are true regarding the sympathetic system EXCEPT:
A. contains a short preganglion
B. postganglionic fibers end at the cardiac plexus
C. is controlled by the cardioacceleratory center
D. All of the above are true
B. postganglionic fibers end at the cardiac plexus
correct statement: sympathetic postganglionic fibers end at the **cardiac nerve**
**Sympathetic system = Cardiac nerve**
**Parasympathetic system = Cardiac plexus**
