Cardiopulmonary - Anatomy and Physiology Flashcards
Lecture #1 (131 cards)
1
Q
What areas are supplied by the circumflex arteries?
A
- Inferior wall of left ventricle (when it’s not supplied by the right coronary artery)
- Left atrium
- Sinoatrial node (around 40% of humans)
2
Q
What areas are supplied by right coronary artery?
A
- Right atrium
- Right ventricle
- Inferior wall of left ventricle (in most humans)
- Atrioventricular (AV) node
- Bundle of His
- Sinoatrial (SA) node (around 60% of humans)
3
Q
What areas are supplied by the left anterior descending artery?
A
- Left ventricle
- Interventricular septum
- Right ventricle
- Inferior areas of the apex
- Inferior areas of both ventricles
4
Q
What percentage of humans does the circumflex artery supply the SA node?
A
around 40% of humans
5
Q
What percentage of humans does the right coronary artery supply the SA node?
A
around 60% of humans
6
Q
In order from the outside, what are the tissue layers of the heart?
A
Fibrous pericardium
Parietal pericardium
- with pericardial cavity in between
Visceral pericardium (also known as epicardium)
Myocardium
Endocardium
7
Q
What is identified as the heart muscle?
A
the myocardium
8
Q
How is the myocardium different from skeletal muscles?
A
Due to automaticity
- there are pacemaker cells that keep the heart moving without conscious voluntary control
9
Q
What influences the myocardium?
A
Both sympathetic and parasympathetic pathways of the autonomic nervous system
External factors also play a role (stress, exercise, caffeine, elicit and Rx drugs)
10
Q
What bundle influences the parasympathetic nervous system and what does it do?
A
Vagus nerve bundle
Some voluntary control over the HR to help it slow down
11
Q
What other elements are associated with the myocardium?
A
Conductive and contractile elements
12
Q
How is the blood supply of the myocardium?
A
Heavily reliant and demanding of O2
13
Q
What are the structures that are lined by the endocardium?
A
myocardium, valves and atria
14
Q
What is the structure of the endocardium?
A
Thin, smooth layer of cells which has some connective tissue and some elastic fibers and muscle tissue
15
Q
What is the function of the endocardium?
A
- has a smooth surface to allow blood and platelets to flow freely and not adhere to heart walls
- strengthens the valves and support other heart tissue
- supports the subendocardial layers
16
Q
What structures are found in the subendocardial layer?
A
Purkinje fibers
17
Q
What valves are within the atrioventricular valves?
A
Tricuspid and mitral
18
Q
Where is the tricuspid valve located?
A
From the right atrium to the right ventricle
19
Q
Where is the mitral valve located?
A
From the left atrium and left ventricle
20
Q
What valves are within the semilunar valves?
A
Aortic and pulmonary
21
Q
Where is the pulmonary valve located?
A
From the right ventricle and pulmonary artery (to lungs)
22
Q
Where is the pulmonary valve located?
A
From the left ventricle and aorta
23
Q
What is the pathway for deoxygenated blood from the body?
A
Vena cava
Right atrium
Tricuspid
Right ventricle
Pulmonary valve
Pulmonary artery
Lungs
24
Q
What is the pathway for oxygenated blood?
A
Through the pulmonary veins
Left atrium
Mitral valve
Left ventricle
Aortic valve
Aorta
Body
25
What is the equation for cardiac output?
CO = HR x SV
26
What is cardiac output?
Amount of blood ejected out of the left ventricle into the systemic vasculature per minute
27
How many liters of blood is ejected at rest?
4-5 L/minute
28
How long does it take for blood to travel through the pulmonary and system circuits?
About 1 minute
29
What happens when one of the cardiac output is compromised?
Compensation occurs which will need outside intervention to compensate
30
What is stroke volume?
Amount of blood ejected out of the left ventricle/beat
31
How much blood is ejected per beat?
55-100 mL/beat
32
What is stroke volume affected by?
left ventricular end diastolic volume and end systolic volume
33
What is left ventricular end diastolic volume?
Amount of blood left in ventricle at the end of diastole
34
What is end systolic volume?
Volume returning to the heart
35
What is preload?
The amount of stretch experienced by cardiac sarcomeres pre-contraction
36
What is Starling's law?
The greater the LVEDV - the greater the stretch and volume pumped
37
What is **DIRECTLY** proportional to stroke volume?
Preload
38
What affects preload?
Affected by venous return and volume of returning blood
39
What is afterload?
the force the left ventricle must generate to overcome aortic pressure to open aortic valve
40
What is **INVERSELY** related to stroke volume?
Afterload
41
What is contractility?
The squeezing pressure of the left ventricle
42
What is ejection fraction?
The percentage of blood emptied from the ventricle during sytole
## Footnote
clinically useful way to understand left ventricle function
43
What is the equation of ejection fraction?
SV/LVEDV
## Footnote
The volume of blood ejected (SV) in relation to the amount of blood received before contraction (LVEDV)
44
What are the normal averages of ejection fraction?
> 55% (60-70%)
45
What does a lower ejection fraction percentage mean?
more impaired the ventricles
46
What does a low EF indicate?
indicator of cardiomyopathy or heart failure
47
What produces a rate pressure product?
HR x SBP
## Footnote
Which increases with activity and with HR and/or BP
48
What does the sympathetic system stimulate?
## Footnote
Also called the adregenic
* Increase HR and force of myocardiaal contraction = increase in myocardial in myocardial O2 demand
* coronary artery vasodilation
49
What controls the adrenergic stimulation?
## Footnote
or sympathetic stimulation
The medulla via T1-T4
50
What is an example of a sympathetic blockers?
Antihypertensives
51
What nodes do the adrenergic innervate?
- SA node
- AV node
- Conduction pathways
52
What controls the parasympathetic stimulation?
## Footnote
or the cholinergic
The medulla via vagus nerve (X) and the cardiac plexus
53
What does the cholinergic innervate?
SA and AV nodes
54
What are the effects of the parasympathetic stimulation?
* Slows rate and force of myocardial contraction = decrease in myocardial demand
* coronary artery vasoconstriction
55
Where are baroreceptors located?
## Footnote
or pressoreceptors
Walls of aortic arch and carotid sinus
56
What reflex responds to BP changes?
circulatory reflex
57
What does an increase in BP result in?
* Parasympathetic stimulation
* decrease rate
* force of contraction
* sympathetic inhibition results in decreased peripheral resistance
58
What does a decrease in BP result in?
- sympathetic stimulation
- increased HR
- increased BP
- vasoconstriction
59
Where are chemoreceptors located?
In the carotid body
- near the bifurcation of the carotid artery
60
What are chemoreceptors sensitive to?
Changes in O2, CO2 and lactic acid (pH) and will affect HR and RR
61
What does increased CO2 or decreased O2 or pH result in?
Increase in HR and RR
62
What is the result of increased O2?
Decreased HR
63
What is hyperkalemia and its outcomes?
Increased concentraction of potassium ions
- decreased HR
- decreased contractile force
- arrhythmias
- EKG changes (wide PR intervals and QRS, tall T-waves)
64
What is hypokalemia and its outcomes?
decreased concentration of potassium ions
* EKG changes (flat T waves, prolonged PR intervals)
65
What is hypercalcemia and its outcomes?
Increased calcium concentration
- increased HR
- Increase inotrophic effectrs
- kidney affected, confusion or coma
66
What is hypocalcemia and its outcomes?
Decreased calcium concentration
- can cause arrhythmias
67
What is hypermagnesmia and it's outcomes?
Increased magnesium concentration and calcium blocker
- calcium blocker
- arrhythmias or cardiac arrest
- hypotension
- Confuction
- lethargy
68
What is hypomagnesmia and its outcomes?
decreased magnesium concentration
- ventricular arrhythmias
- coronary artery vasospam
69
Where does action potential start?
At the SA node which depolarizes the atria which then spread to the AV node
70
Why is there a .1 second delay during depolarization?
Allowing for the atria to contract and ventricles to fill
71
What is systole?
The period of contraction that the heart undergoes while it pumps into circulation
72
What is diastole?
The period of relaxation that occurs as the chambers fill with blood
73
What happens to the coronary arteries during diastole?
It perfuse the myocardium duyring diastole through the capillaties
As the aortic valve snaps shut leftover blood and is shunted to the coronary arteries
74
What areas involved in gas exchange?
Only the respiratory zone and not the conducting zone
75
Describe the pleurae of the lungs
A double layered membrane that folds back on itself
- visceral: innermost
- parietal: outermost
76
What is present in the pleural cavity?
## Footnote
Analgous to the pericardial cavity
Pleural fluid
77
What is the purpose of the pleural fluid?
Creating surface tension to keep the lungs in place of the thorax which lets the lungs to expand when the thorax expands
Cushions and lubricates the lungs during expansion and retraction
78
What happens when tension in the pleura is lost?
the lungs collapses
| pneumothorax
79
What innervates the parietal pleura?
Phrenic and intercostal nerves
## Footnote
allows for pain, temperature and touch
80
What is the **accessory ** muscles of the inspiration?
- SCM = elevates sternum
- scalenes group = elevate upper ribs
- pectoralis minor
81
What is the **principal ** muscles of the inspiration?
* external intercostals (interchondral part of internal intercostals) = elevates the ribs
* diaphragm = dome descends and increasing vertical dimension of thoracic cavity. elevates lower ribs
82
Muscles of quiet breathing of expiration
Expiration results from passive, elastic recoil of the lungs, dib cage and diaphragm
83
Muscles of the quiet breathing of active breathing
- internal intercostal except interchondral part = pulls ribs down
- abdominals = pulls ribs down, compress abdominal contents thus pushing diaphragm up
- QL = pulls ribs down
84
What is atmospheric pressure?
Pressure exerted on the lungs by the outside atmosphere
85
What is intra-alveolar pressure?
Pressure exerted within the alveoli
86
What is intrapleural pressure?
Pressure within the two layers of the pleurae
87
What creates an inward pull?
Elasticity of the lungs and the surface tension of the alveoli
## Footnote
Surfactant prevents the alveoli from collapsing during experiation
88
What creates an outward pulls?
Surface tension within the pleural cavity
## Footnote
Parietal pleura attached to thoracic wall
89
What is pulmonary ventilation?
Air moving in and out of the lungs
90
What is the muscular process of inspiration?
* Diaphragm contracts = thorax expands inferiorly
* External intercostals contract = pulls ribs up and out = expands thorax anteriorly
* this creates a pressure gradient which drives air into the lungs
91
Is normal expiration active or passive?
Largely passive
92
What is the muscular process of expiration?
* Diaphragm and external intercostals relax
* The natural elastic recoil of the lungs puts the thorax back to normal = decreases volume of the thorax
* creating a pressure gradient and drives air out the lungs
93
What is the physical properties of the lungs to help with breathing?
- lung compliance = distensibility (extend) of lung tissue (balloon)
- tendency of the lungs to recoil (collapse)
- elastic recoil or elasticity
- surface tension at air-liquid interface on the alveolar surface to collapse alveoli
- resistance to airflow at the level of the airway
94
What is transmural pressure?
The difference between the intrapulmonary pressure and intrapleural pressure
- this needs to be maintained through a distending (expanding) force
95
How is distending force provided?
Provided by inspiratory muscles and complaince and elastic properties of the lungs
96
What surrounds the alveolar network?
Elastin and collagen which surrounds the surrounding capillaries and bronchi
97
What counters the surface tension on the alveolar surface?
Surfactant
98
Clinical application of scoliosis for breathing
impairs the ability of the ribcage to expand which impairs the ability of the lungs to expand
99
Clinical application of pulmonary fibrosis for breathing
impairs compliane of lungs
100
Clinical application of COPD for breathing
over inflates the lungs by trapping air so it affects the elasticity of the lungs
101
Clinical application of asthma for breathing
increasing resistance to airflow due to brochoconstriction
102
Clinical application of premature babies (< 7 months) for breathing
reduces surfactant = alveolar collapse
103
Clinical application of TBI for breathing
Neural control of breathing
104
Where in the brain controls breathing?
Medulla and pons
105
What does breathing require?
Repetitive stimulation from the brain and nerve stimulation to muscles
106
What is respiration driven by and what does it stimulate once a certain level is reached?
Driven by CO2 and pH levels
- this stimulates the central chemoreceptors in the medulla
107
What occurs once CO2 increases?
pH decreases which stimulates the respiratory centers in the medulla
- this contracts the diaphragm and external intercostals = increases the rate and depth of respiration
108
Where are peripheral chemoreceptors located?
In the carotid artery and aortic arch
109
What occurs as CO2 decreases?
pH increases = respiratory centers to lower rate and depth of respiration
110
How does peripheral chemoreceptors influence respiratory centers?
* Driven by the chemoreceptors for CO2 vs O2
* Increasing ventilation because of increases levels of CO2
* Increased ventilation because of lower levels of CO2
111
What is hypercapnia?
Increase ventilation because of increased CO2 levels
112
What is hypoxia?
Increased ventilation because of decreased CO2 levels
113
What occurs with chronic COPD patients regarding breathing?
They trap CO2 and start to rely more on O2 receptors = hypoxic drive to breath
114
How is supplemental O2 administered for chronic COPD patients?
cautiously administered because the increased O2 saturation will suppress the hypoxic drive to breath
115
What other systems influence breathing?
Hypothalamus and limbic
- i.e anxiety or stress can increase rate. fear can cause holding breath
116
What is gas exchange?
Respiration
117
What is the primary role of the pulmomary system?
get O2 in and CO2 out
118
Where does gas exchange occur?
Occurs in the respiratory zone of the lungs closer to the bottom because of its smaller but has more alveoli at the base
- gas diffuses across membranes down a concentration gradient
- driven by gases in the air and blood pH
119
How does effective has exchange occur?
Alveoli must be both:
- ventilated = flowing in and out
- perfused = blood flowing into alveoli capillaries
120
What is the goal for ventilation?
V to be matched by perfusion > Q (V/Q match)
- V/Q mismatch - pathological state
121
What can impact ventilation and perfusion?
Positioning
122
How does non-uniform ventilation affect gas exchange?
* Areas of the lungs with greater perfusion act as shunts
* Areas with greater ventilation considered dead space
123
How is O2 and CO2 transported?
Veins carry CO2 to the lungs
Arteries carry O2 from lungs to peripheral tissues
124
What does hemoglobin HgB made of?
4 iron molecues -hemes
4 protein molecules -globins
## Footnote
Exists in different forms
125
What is oxyhemoglobin?
Hgb carrying O2
126
What is doxyhemoglobin?
Hgb that has released O2 to peripheral tissues
127
What is carboxyhemoglobin?
Hgb bound to CO instead of O2 = which is **abnormal**
128
Hgb tranports how much O2 and to where?
Transports 98% of O2 to the periphery with 2% in plasma
129
What is SaO2?
Oxyhemoglobin/total hemoglobin (blood gas analysis)
## Footnote
called SpO2 when measured with pulse oximeter
130
What is the O2 carrying capacity of the body?
Determined by concentration of Hgb
- Women = 12-16 g/dL
- Men = 13-16 g/dL
131
What is anemia?
Lower than normal concentration of Hgb which impairs the body's ability to circulate O2
