Midterm semester 2 Flashcards
1
Q
What are the two primary defense mechanisms for fighting infection?
A
Lymphatic system
White blood cells
2
Q
What are the three main parts of the lymphatic system
A
Lymphatic vessels
Lymph fluid
Lymph nodes
3
Q
What is the primary function of the lymphatic vessels?
A
Transport lymph (which contains WBCs) throughout the body
Pick up and return excess interstitial fluid to the blood stream
4
Q
What are the three clusters of lymph nodes and where are they located?
A
Cervical = in the neck
Axillary = in the armpit
Inguinal = in the groin
5
Q
What is the average amount of interstitial fluid found in the interstitial spaces?
A
About 11 liters
6
Q
In a healthy individual, how is the majority of the interstitial fluid returned to the bloodstream?
A
Oncontic pressure pulls the fluid back into the veins
7
Q
What is the basic function of the lymph nodes?
A
filter /clean the lymph flowing through them prior to returning the lymph to the systemic circuit
This is done by lymphocytes
8
Q
What is hydrostatic pressure?
A
Pressure of the blood exerted on the membrane of the capillary. Pushes fluid out of capillary into interstitial space. Pressure is greater on the arterial side than the venous side
9
Q
What is oncotic pressure?
A
Pressure that pulls water back into the capillary and/or prevents it from leaving
10
Q
What generates oncotic pressure?
A
Plasma proteins such as albumin which cannot cross the wall of the capillary.
11
Q
What is interstitial oncotic pressure?
A
The pressure related to the amount of proteins in the interstitial fluid. If protein levels are increased, more fluid is pulled out of capillaries into interstitium
11
Q
What is interstitial hydrostatic pressure?
A
Hydrostatic pressure of the fluid in the interstitium, can be thought of as “zero” which allows for fluid to pass out of capillaries and be pulled into the lymphatic vessels. If pressure increases this can result in more fluid being absorbed back into the capillaries
12
Q
T/F: The distribution of lymphatic vessels throughout the lungs is ubiquitous
A
False. There are more lymphatic vessels on the SURFACE of the lower lobes than on the upper and middle lobes
12
Q
Where does the thoracic duct drain fluid from?
A
From tissues inferior to the diaphragm and the left side of the body
12
Q
Where does the right lymphatic duct drain fluid from?
A
The right lymphatic duct drains fluid from the right half of the body superior to the diaphragm
13
Q
T/F: lymphatic vessel are found in the walls of the alveoli
A
False. Lymphatic vessels are found in the interstitial spaces to help drain fluids and foreign materials
14
Q
Where does the thoracic duct drain lymph into?
A
The left subclavian vein
15
Q
Where does the right lymphatic duct drain lymph into?
A
The right subclavian vein
15
Q
lymph enters the lymph nodes through the efferent lymphatic vessels
A
False. Lymph enters the lymph nodes through the afferent lymphatic vessels
Efferent = get the “F” outta here
16
Q
A
The cysterna chyli
17
Q
The cysterna chyli marks the beginning of what?
A
The thoracic duct
18
Q
Describe the cysterna chyli
A
The cysterna chyli is a dilated sac at the lower end of the thoracic duct in most mammals
Serves as a reservoir for lymph
Marks the starting point of the thoracic duct
19
Q
What are the 5 types of WBCs that we care about? (at the moment)
A
Monocytes aka macrophages
Lymphocytes
Eosinophils
Basophils
Neutrophils
20
Q
What are the 2 types of lymphocytes?
A
T cells
B cells
20
What is another name for a macrophage?
Monocyte
21
What is a normal WBC count?
4000-10000 (4-10 on reports)
22
What is the purpose of getting a WBC differential?
Can help diagnose infection
23
What is a leukemoid reaction?
An extreme increase in the number of white blood cells
50,000 or more
24
What would a WBC differential with 90% lymphocytes indicate in a patient with pneumonia?
That that the pneumonia is viral
24
What does a complete blood count do?
Quanitifies RBCs
Determine the number and type of WBCs
24
What is leukopenia?
Too few WBCs
Less than 4000
25
What would a WBC differential with 90% neutrophils indicate in a patient with pneumonia?
That the pneumonia is bacterial
26
What are bands/stabs?
Immature neutrophils
26
What does an increase in the number of bands or stabs indicate?
Indicates and increase in immature newly formed neutrophils which occurs in an acute inflammatory response
27
What are mature neutrophils referred to as?
Segs
27
What can an increase in the number of bands/stabs also be called?
A shift to the left
28
What are the first white blood cells at the site of an acute inflammatory response?
Neutrophils
29
What is the normal range for neutrophils in a WBC diff?
40-75%
25-80%
40-60%
30
Why does a shift to the left occur in acute inflammatory responses?
Bone marrow releases neutrophils
Neutrophils begin fighting infection
Neutrophils do not have a long life span
Bone marrow releases immature neutrophils to fight infection while macrophages are activated and take over as the predominant WBC at site of injury/infection/inflammation
30
What is the normal range for lymphocytes in a WBC diff?
20-45%
20-50%
20-40%
31
What is the normal range for monocytes in a WBC diff?
2-10%
2-12%
2-8%
31
What is the normal range for eosinophils in a WBC diff?
0-6%
0-7%
1-4%
32
What is the normal range for basophils in a WBC diff?
0-1%
0-2%
0.5-1%
33
What is the normal range for bands in a WBC diff?
0-6%
0-10%
0-3%
34
What is the role of the spleen?
Produces and stores WBCs
When it detects bacteria or viruses the spleen with produce lymphocytes
34
What are the other organs in the body responsible for fighting infection?
Tonsils
Spleen
Thymus
34
What is the function of the tonsils in children?
Trap inhaled viruses and bacteria
Produce lymphocytes to destroy “invaders”
This function diminishes as a child reaches the age of 3
35
What is the role of the thymus in fighting infections?
Produces progenitor cells which mature into T-cells
35
Where in the brain are the respiratory centers located?
The brainstem
36
The dorsal and central respiratory groups are located where?
In the medulla
36
The pneumotaxic center and the apneustic center are located where?
In the pons
37
Where is the pneumotaxic center located in the pons?
The upper portion
38
Where is the apneustic center located in the pons?
Lower pons
38
What does the apneustic center control?
Triggers inspiration only
38
What does the pneumotaxic center control?
Triggers inspiration
Senses lung expansion and inhibits inspiration to allow for expiration
39
T/F: The apneustic center fine tunes respiratory rate and depth
False. The pneumotaxic center fine tunes RR and depth
39
What kind of signals does the pneumotaxic center send and where does it send them?
Sends inspiratory and expiratory signals/implulses to the medullary respiratory groups
40
What happens if the pneumotaxic center is damaged
The Apneustic center will “take over” and without the pneumotaxic center inhibiting inspiration, the individual will take very long very deep gasping breaths called apneustic breathing
41
What kind of signals does the pneumotaxic center send and where does it send them?
Sends inspiratory signals/impulses to the medullary respiratory groups to trigger inspiration
41
Where is the DRG located in the medulla?
Bilateral groups of neurons located in the posterior medulla
42
Where does the DRG receive information from?
Receive information and stimuli from the pontine centers
42
Where is the VRG located in the medulla?
Bilateral group of neurons located in the anterior medulla
43
Where does the DRG send signals to and what do these signals do?
Send signals to the diaphragm and external intercostals to trigger inspiration
44
Where does the VRG receive information from?
Receive information and stimuli from the pontine centers
45
Where does the VRG send signals to and what do these signals do?
Inspiratory and expiratory neurons send signals to diaphragm and external intercostals to trigger inspiration and expiration
Also send signals to internal intercostals and abdominals to support active expiration
45
What are the VRG comprised of?
Botzinger complex: expiratory neurons
pre-Botzinger complex: pacemaker neurons
Nucleus retroambiguus: inspiratory and expiratory neurons
Nucleus ambiguous
46
What nerve exits from C3-C5 and what does it innervate?
Phrenic
Diaphragm
46
What nerve exits from C8-T11 and what does it innervate?
Intercostal nerve
External intercostals
47
Where is the central chemoreceptor located?
Posterior portion of the medulla
47
Where are the peripheral chemoreceptors located?
Above the aortic arch
At the bifurcation of the common carotid where they divide into an internal and external carotid artery
48
What are the mechanical receptors located in the lung
Irritant receptors
Stretch receptors (herring breuer reflex)
Juxtacapillary receptors
Deflation reflex
48
What are the central chemoreceptors sensitive to?
Changes in pH due to increases in CO2 in the blood
49
What are the receptors located in the muscles and joints?
Peripheral proprioceptors
50
What is the primary stimulus for breathing in healthy individuals?
PaCO2
50
What are peripheral chemoreceptors sensitive to?
PaO2
pH
PaCO2
51
How do the carotid bodies send information back to the respiratory centers?
Carotid sinus nerve
Glossopharyngeal nerve
51
How do the aortic bodies send information to the respiratory centers?
Via the vagus nerve
52
What are the different stimuli that the peripheral chemoreceptors can react to?
PaO2 < 60 mmHg
Increased PaCO2
Decreased pH
52
What is the primary stimuli that the peripheral chemoreceptors will react to?
A PaO2 of less than mmHg
53
What does dopamine do in regards to respiration?
Will act to stimulate the degree and frequency of impulses/electrical activity/action potentials sent to the respiratory groups
53
When the peripheral chemoreceptors are activated, what will they do?
Release dopamine
54
What effect does hypoxemia have on the peripheral chemoreceptors?
Makes them much more sensitive to changes in hydrogen ion concentration
54
What is the secondary stimulus for breathing in healthy individuals?
Arterial hypoxemia
Not clinically significant unto PaO2 < 60 mmHg
55
Where are the stretch receptors located in the lungs?
Visceral pleura
Bronchial smooth muscle of the bronchi/bronchioles
55
Where are the irritant receptors located?
Epithelial cells of the airways (larynx, trachea, bronchi, bronchioles)
55
Describe the herring breuer reflex
A big tidal volume will inflate and stretch the lungs which will be detected by the stretch receptors in the visceral pleura and smooth muscle of the bronchioles which will then send impulses to the DRG to stop inspiration
56
What do irritant receptors respond to and how to they respond
Respond to chemical irritants
Trigger a cough or sneeze reflex
Can also narrow the glottis and sometimes cause bronchoconstriction or tachypnea
Can also cause a vasovagal response
56
What is a vasovagal response?
Characterized by a sudden onset of dizziness, lightheadedness, nausea and syncope
57
What can trigger a vasovagal response in a clinical setting?
Suctioning, bronchoscopy, endotracheal intubation
57
What parts of the body cause the vasovagal response?
Blood vessels
Vagus nerve
57
What happens physiologically during a vasovagal response?
Sudden drop in heart rate and blood pressure
58
What does the deflation reflex trigger?
An increase in respiratory rate to compensate for a loss of volume
59
When might the deflation reflex be triggered?
During a pneumothorax
60
Where are the juxtacapillary receptors located?
In the AC membrane on the walls of the alveoli near the walls of the pulmonary capillaries
61
What can triggering the juxtacapillary receptors cause?
Dyspnea
Rapid shallow breathing
61
What are the juxtacapillary receptors sensitive to?
Alveolar inflammation
Pulmonary vascular congestion (CHF)
Increased levels of fluid in the interstitial space and alveoli
62
What triggers the proprioceptors?
Increased movement during exercise
Pain in muscles and joints
63
Where are the proprioceptors located?
Muscles, joints, tendons
64
Describe ataxic breathing
Characterized by complete irregularity of breathing
Irregular pauses and increasing periods of apnea
As breathing pattern deteriorates, it merges with agonal respiration
65
Describe cheyne-stokes breathing
Gradual increase in volume and rate followed by gradual decrease in volume and rate
Apnea periods of 10-30 seconds between cycle
Cyclic
66
Describe biots breathing
Similar to cheyne stokes breathing but Vt is constant except in apnea periods. Short episodes of rapid deep inspirations follow by 10-30 second apneic period
66
Describe Kussmaul breathing
Increased rate and depth of breathing over a prolonged period of time
Response to metabolic acidosis
Frequently seen in adults with diabetic ketoacidosis
67
What could cause Cheyne-stoke breathing?
CHF
Basal ganglia/thalamus damage
Metabolic trauma or infarction
Increasing intracranial pressure
Brain stem injury
67
If a clinician insists on hyperventilating a patient, what should you know?
There is no benefit if intracranial pressure is normal
There is no benefit if it decreases after 24-48 hours due to compensatory mechanisms of the kidneys
Cerebral blood flow is lowest in the first 24 hours following an injury, wait to hyperventilate until day 2 or 3
67
What could cause apneustic breathing?
Damage in rostral pons
stroke
67
What could cause ataxic breathing?
Damage in caudal pons
68
What could cause Kussmaul breathing?
Metabolic or keto Acidosis
Renal failure
68
What could cause biot breathing?
Damage in medulla
Spinal meningitis
Head injury
68
What effect does CO2 have on cerebral blood vessels?
Dilates cerebral blood vessels
Increases intracranial pressure
69
What effect does decreased PaCO2 have on cerebral blood vessels?
Constricts cerebral blood vessels and decreases intracranial pressure
May reduce cerebral blood flow if reduced too much
69
What is the difference between efferent and afferent neurons
Efferent neurons are motor neurons that carry neural impulses away from the CNS and towards the effectors
Afferent neurons are sensory neurons that carry information from sensory stimuli towards the CNS
69
What generates the elastic recoil force of the lungs?
Surface tension forces
Elastin and collagen fibers in the lung parenchyma
70
What is the normal amount of compliance in healthy lungs?
About 200 ml/cmH2O
70
Describe dynamic lung compliance
Pressure need to move a volume of air into the lungs
70
What conditions can make compliance worse?
Atelectasis
Pneumonia
Pulmonary edema
Lack of surfactant
ARDS
Pneumothorax
Fibrosis
Restrictive lung diseases
71
Describe static compliance
Pressure needed to maintain a volume of air in the lungs once it has been delivered
71
What is the formula for static compliance
Cstat = Vt / Plat-PEEP
71
What is the formula for dynamic compliance?
Cdyn = Vt / PIP-PEEP
72
What is required to measure plat?
A period of no gas flow when the lungs are fully inflated with known Vt accomplished by initiating an inspiratory hold
72
Describe PIP
The amount of pressure required to move a given volume of air into the lungs
73
Describe Plat
The amount of pressure required to maintain a given volume of air in the lungs
74
What is the Raw of normal healthy airways?
0.5-2.5 cmH2O/L/sec
74
Where is the most resistance found in healthy lungs?
In the larger conducting airways
Resistance decreases as the airways get smaller due to larger overall diameter
74
Describe PEEP
The amount of pressure that remains with the lung at the end of expiration
74
What are some clinical causes of increased Raw?
Obstructive lung diseases
Bronchospasm
Increase in secretions
Water in tubing
Displaced or kinked ETT
75
Describe mean airway pressure
The mean pressure applied during mechanical ventilation
Area “under the curve”
76
What are the components of resistance for the lung?
Tissue resistance
Airway resistance
76
What is the formula for determining Raw?
Raw = PIP-Plat / flow in L/s
77
What is the normal value for static lung compliance?
50-100 ml/cmH2O
77
What is the normal compliance of the chest wall in healthy adults?
200 ml/cmH2O
77
What is the normal compliance of the lungs in healthy adults?
200 ml/cm H2O
77
Describe the interaction between the chest wall compliance and compliance of the lungs
The two components are elastically opposed to one another. The chest wall is attempting to recoil out from the lungs while the lungs are trying to recoil in from the chest wall. Because of this, we must consider the compliance of the system as a whole
77
What is clinically acceptable Raw?
10-15 cmH2O/L/sec when intubated
77
What is the normal value for dynamic lung compliance?
30-50 ml/cmH2O
77
What are the 4 major pressures involved in ventilation
Pao = pressure at the airway opening
Palv/Pa = intrapulmonary pressure or pressure within alveoli
Ppl = pressure in pleural cavity
Pbs = pressure at the body surface
78
What is the compliance of the entire system (Crs) in normal healthy adults?
100 ml/cmH2O
78
Pressure at the airway opening can also be called…
Pao
Pm
Patm
Pb
78
Why is it important that there is negative pressure in the pleural space?
Prevents alveolar collapse
Maintains FRC
78
Intralveolar pressure can also be referred to as…
Alveolar pressure
Intrapulmonary pressure
Pa
Palv
79
What do you call the pressure in the pleural space?
Pleural pressure
Intrapleural pressure
Ppl
Pip
79
In a person who is breathing without assistance, the pressure in the pleural space should always be…
Negative
79
What happens to intrapulmonary/intra-alveolar pressure when you inhale (unassisted)?
Decreases as lung volume increases
80
What is body surface pressure referred toas?
Pbs
81
Describe transairway pressure
The pressure difference between airway opening and alveolar pressure
81
Describe transchest wall pressure
Pressure difference between pleural pressure and body surface pressure
81
Describe boyles law
Describes the relationship between pressure and volume of a gas
States that as volume increases, pressure decreases and vice versa
Remember, temperature and # of molecules must be held constant to apply boyles law
81
Describe transrespiratory pressure
The pressure difference between alveolar and body surface pressure
81
Describe transthoracic pressure
Pressure difference across the thoracic wall
81
What happens to intrapleural pressure when you inhale (unassisted)?
Becomes more negative as the chest wall moves away from the lungs and pulls them with it
82
What does a hysteresis curve demonstrate?
The difference between inspiratory and expiratory compliance
82
What does hookes law state?
An elastic structure changes dimensions in direct proportion to the amount of force applied
82
What does the hysteresis curve tell us about how the lung behaves during inhalation and exhalation?
It tells us that there are more factors at play than just elasticity. If elasticity was the only thing affecting the curve, inhalation and exhalation would look identical
83
T/F: Lung volume at any given pressure is greater during inhalation than lung volume at any given pressure during exhalation
False. Lung volume at any given pressure is less during inhalation than the lung volume at any given pressure during exhalation
83
Describe transpulmonary pressure
Measures the difference in pressure between the inside and outside of the lung
84
Why does the inhalation curve look different than the exhalation curve on a hysteresis loop?
During inhalation, additional energy in the form of pressure is needed to overcome surface tension forces to recruit and inflate alveoli.
85
Why does the hysteresis curve for inhalation start out flattish then move more vertically? (in health people)
When inhalation begins, the alveoli are deflated and surface tension is at its highest point. This has to be overcome with the initial portion of inspiration in order for the lungs to inflate and as a result the curve is relatively flat
