Exam 2: Lymphatic & Respiratory Flashcards
1
Q
Functions of the Lymphatic System
A
Fluid Recovery
Immunity
2
Q
Lymph
A
Clear, colorless recovered fluid. It is similar to blood plasma but low in protein
3
Q
Lymphatic Capillaries
A
Microscopic vessels that penetrate nearly every tissue of the body, picking up fluid near capillaries and tissues and sending it back to the lymph vessels.
Fluid enters the capillaries through small openings in the endothelium
4
Q
How do valves in the lymphatic vessel endothelium function?
A
The valve-like flaps in the lumen open when interstitial fluid pressure is high, allowing fluid to flow in. They close when pressure is low.
5
Q
Where are most lymph nodes found?
A
Areas where parts of the body connect
Ex. Elbow, groin, armpit, neck, knee, etc.
6
Q
Why do lymph nodes become swollen?
A
When an infection is present, fluid flow in the lymph nodes is greater in an attempt to filter the fluid more
7
Q
What are the primary methods of lymphatic flow? (3)
A
Respiratory Pump - Similar to the venous return chest pump
Muscular Pump - Skeletal muscles “massage” lymph nodes, pushing fluid back toward the heart
Gravity - Fluid in the lymphatic vessels above the heart flows downward
8
Q
Natural Killer Cells
A
Large lymphocytes that patrol the body for pathogens or diseased cells
Upon recognition of an enemy cell, the NK cell binds to it and releases perforins, which polymerize a ring in the plasma membrane.
They pump protein-degrading granzymes into the cell, inducing apoptosis
9
Q
T Lymphocytes (T cells)
A
Lymphocytes that mature in the thymus and depend on thymic hormones
10
Q
B Lymphocytes (B cells)
A
Lymphocytes that mature in the bone marrow and turn into plasma cells
They make A & B antibodies
11
Q
Macrophages
A
Large, avidly phagocytotic cells of the connective tissues
They are Antigen-Presenting Cells (APCs) that alert the immune system
12
Q
Antigen-Presenting Cells (APCs)
A
Cells that phagocytize debris and process the foreign matter. The antigens of the foreign cells are then presented on the outside of the cell
Macrophages and Dendritic Cells are APCs
13
Q
Dendritic Cells
A
Branched, mobile APCs found in the epidermis, mucous membranes, and lymphoid organs.
They alert the immune system to pathogens that have breached the body’s surface, engulfing foreign matter and migrating to lymph nodes to activate immune responses
14
Q
Primary Lymphatic Organs
A
Red Bone Marrow - B cell maturation and immunocompetence
Thymus - T cell maturation and immunocompetence
15
Q
Secondary Lymphatic Organs
A
Lymph Nodes
Tonsils
Spleen
Immunocompetent cells populate these tissues
16
Q
Lymph Node Structure
A
Cortex - Comprised of the Subscapular Sinuses and the Lymphatic Nodules
Inner Medulla - Extends to the surface at the hilum
17
Q
What cells are found in the Subscapular Sinuses?
A
Macrophages & Dendritic Cells (APCs)
18
Q
What cells are found in the Lymphatic Nodule?
A
T cells that respond to the markers found on the APCs from the subscapular sinuses
19
Q
What cells are found in the Inner Medulla?
A
B & T cells communicate with T cells from the lymphatic nodules; B cells become plasma cells and begin to produce antibodies
20
Q
Tonsils
A
Lymphatic Tissue located near the pharynx that is full of WBCs. When substances come into contact with the tonsils, the immune system is alerted
Pharyngeal, Palatine, and Lingual
21
Q
Spleen
A
The body’s largest lymphatic organ whose main function is to digest RBCs.
Red Pulp - Sinuses filled with RBCs
White Pulp - Contains lymphocytes (T & B) and macrophages that monitor the blood for foreign antigens
22
Q
Metastasis
A
Cancer cells break free from their original tumors and travel to other sites where new tumors are established
Metastasizing cells easily enter lymphatic vessels and tend to lodge in the lymph nodes, multiplying and eventually destroying the node
23
Q
First Line of Defense
A
Epithelial Barriers (skin & mucous membranes)
24
Q
Second Line of Defense
A
Interior, non-learning defense (leukocytes, macrophages, antimicrobial proteins, NKCs, fever, inflammation)
25
Third Line of Defense
Adaptive Immunity. Mechanisms that defeat a pathogen and leave the body with a memory of it
26
Innate Defenses
Defense mechanisms that one is born with, they have no memory and guard against a broad range of pathogens. There are three kinds:
Protective Proteins
Protective Cells
Protective Processes
27
Adaptive Immunity
A mechanism through which the body develops separate immunity to each pathogen (specific)
28
Skin External Barrier
Difficult for microorganisms to enter the body because:
Tough keratin
Too dry and nutrient-poor for microbial growth
Acid Mantle - A thin film of lactic and fatty acids that inhibit bacterial growth
Dermicidin, defensins, and cathelicidins - Peptides in the skin that kill microbes
29
Mucous Membrane External Barrier
Mucus physically traps microbes
Lysozyme - An enzyme found in mucus, tears, and saliva that destroys bacteria
30
Innate Leukocytes
Neutrophils, Eosinophils, Basophils, Lymphocytes, and Monocytes
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Neutrophils
Innate
They wander through connective tissues, killing bacteria via phagocytosis and digestion
By degranulating its lysosomes and discharging its enzymes into tissue fluid, it creates a respiratory burst/killing zone to eliminate viruses
32
Eosinophils
Found in mucous membranes
Kills tapeworms and roundworms by producing superoxide, hydrogen peroxide, and toxic proteins
Promotes the action of basophils and mast cells
Phagocytize antigen-antibody complexes
Secrete enzymes that degrade and limit the action of histamine and other inflammatory chemicals
33
Basophils
Secrete chemicals that aid mobility and actions of other leukocytes
Leukotrienes - activate and attract neutrophils & eosinophils
Histamine - a vasodilator, speeding the delivery of leukocytes to the area
Heparin - inhibits clot formation
34
Lymphocytes
T, B, and NK cells
T & B cells are part of adaptive immunity
NK cells are part of innate immunity
helper T cells function in both
35
Monocytes
Emigrate from the blood into connective tissues where they become macrophages
Macrophage System
Activated by Interferons
36
Macrophage System
All of the body's avidly phagocytic cells that aren't leukocytes. Includes:
Wandering Macrophages - Actively seeking pathogens, distributed throughout loose connective tissue
Fixed Macrophages - Phagocytize only pathogens that come to them
37
Fixed Macrophages (3)
Microglia - In the CNS, they originate in the immune system
Alveolar Macrophages - In the lungs
Hepatic Macrophages - In the liver, they fight off alcohols & other toxins
38
Interferons
Produced by infected cells, they bind to healthy cells to warn them of viruses.
Once the interferon binds to a healthy cell, it turns on genes to code for antiviral proteins that block viral reproduction
They are specific and have no memory
39
Complement System
A group of 30+ defensive proteins that amplify all aspects of the inflammatory response, kill bacteria through lysis, and can be used in both learning and non-learning systems
40
Fever
An adaptive defense mechanism
Initiated by exogenous pyrogens, fever-producing agents that originate outside the body
These pyrogens stimulate neurons of the anterior hypothalamus to increase body temp.
It is a negative feedback system that raises the homeostatic temperature
Metabolic & reproductive functions are increased so the body can fight off the virus
41
Inflammation & the major processes (3)
A local response to tissue injury or infection. Three major processes:
Mobilization of Body Defenses
Containment& Destruction of Pathogens
Tissue Cleanup & Repair
42
Inflammation: Mobilization of Body Defenses
The goal is to get defensive leukocytes to the site quickly
Achieved by local hyperemia (increased blood flow)
Vasoactive chemicals increase capillary permeability, allowing larger cells to escape (clotting, complement, and antibody proteins)
Selectins recruit leukocytes and cause margination (WBCs "smelling" the chemicals of the injury site)
43
Margination
WBCs "smell" the injury chemicals, change in shape, and "crawl" along the capillary wall as they get closer to the site of injury
During this process, they look for places on the capillary walls where they can escape
Chemotaxis is the process of following the chemical trail
If the WBC is a macrophage, it will begin to digest the bacteria
44
Inflammation: Containment and Destruction of Pathogens
Neutrophils respond within an hour of the injury, secreting cytokines for further recruitment of macrophages and neutrophils
Macrophages and T cells secrete colony-stimulating factors that stimulate leukopoiesis, further raising WBC counts
45
Inflammation: Tissue Cleanup & Repair
Monocytes are the primary agents of cleanup and repair, arriving in 8-12 hrs and becoming macrophages. They destroy bacteria, damaged, and dead cells
Edema (swelling) compresses veins and reduces venous drainage and forces lymphatic capillary valves open
Pus is comprised of dead neutrophils, bacteria, and cellular debris
Increased heat increases the metabolic rate which speeds mitosis and repair
46
Cardinal Signs of Inflammation/Signs of Healing
Pain, Redness, Swelling, & Heat
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Cytokines
Small proteins that serve as a chemical communication network among immune cells
48
Defining Characteristics of Adaptive Immunity
Systemic Effect - When an adaptive response occurs, it acts throughout the body
Specificity - Adaptive immunity is sharply focused on a specific invader
Memory - Reexposure produces a quicker reaction
49
Forms of Adaptive Immunity (2)
Cellular
Humoral
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Cellular Adaptive Immunity
Cell-mediated/T cell immunity employs lymphocytes that directly attack and destroy foreign cells or diseased host cells that house pathogens
51
Humoral Adaptive Immunity
Antibody-mediated/B cell immunity employs antibodies that don't directly destroy pathogens, but rather tags them for destruction
52
Natural Active Immunity
Immunity acquired by the natural exposure to an antigen
53
Artificial Active Immunity
Immunity acquired by the result of a vaccination
54
Natural Passive Immunity
Temporary immunity that results from acquiring antibodies produced by another person
55
Artificial Passive Immunity
Temporary immunity that results from the injection of an immune serum obtained from another person or animals with those antibodies
56
Active vs. Passive Immunity
The active immune system has memory
The passive immune system doesn't
57
Antibodies
AKA immunoglobulins, they are proteins in the gamma globulin class that help with defense
58
Antibody Structure
V region - Variable region in all four chains that gives the antibody its uniqueness
C region - Constant region in each chain that gives the antibody its class
59
Antibody Classes (5)
IgA
IgD
IgM
IgE
IgG
60
IgA Antibody
In mucus, saliva, tears, milk, and intestines, they prevent pathogen adherence to epithelia and penetration of underlying tissues
Provides passive immunity to newborns
61
IgD Antibody
B cell transmembrane antigen receptor that is thought to function in B cell activation by antigens
62
IgM
A pentamer in plasma and lymph that is secreted in primary immune response. It causes agglutination and complement fixation
63
IgE
Acts on basophils, stimulating the release of histamine and other chemical mediators of inflammation and allergy
Attracts Eosinophils to infection sites and produces immediate hypersensitivity reactions
64
IgG
Constitutes 80% of the circulating antibodies
Crosses from the placenta to the fetus, secreted in secondary immune response and complement fixation
65
How many different antibodies can the human immune system produce?
1 trillion
66
Categories of Lymphocytes
NK Cells
T cells
B cells
67
What happens to T cells in the Thymus?
Cortical epithelial cells release chemicals that stimulate maturing T cells to develop surface antigen receptors.
These receptors make the T cells immunocompetent
Medullary epithelial cells test the T cells by presenting self-antigens to them
Only 2% of T cells pass both positive and negative selection tests and are deployed
68
Immunocompetency: Positive Selection
The MHC of an APC and the T cell receptor bind together. If the T cell recognizes the MHC, it passes, otherwise the T cell is killed.
69
Immunocompetency: Negative Selection
T cells that passed positive selection tests then check for recognition of the self-antigen. If the self-antigen is recognized, meaning the T cell would attack it, thus the T cell is killed before that happens. If the self-antigen is not recognized, the T cells will not attack the host cells
70
Naive Lymphocyte Pool
Immunocompetent T cells that have yet to encounter foreign antigens
71
B cell Immunocompetency
B cells mature in the red bone marrow
Self-tolerant B cells synthesize their own antigen receptors and divide rapidly, producing clones
Once mature, B cells leave the bone marrow and colonize the same lymphatic tissues and organs as T cells
72
Antigen-Presenting Cells
Allow T cells to recognize antigens.
Dendritic cells, macrophages, reticular cells, and B cells function as APCs
APC function is determined by the Major Histocompatibility Complex (MHC) proteins that act as ID tags for every cell of your body
73
Antigen Processing in APCs
The APC encounters an antigen
Endocytosis occurs, taking the antigen into the cell
The cell's lysosome fuses with the phagosome, mixing enzymes and antigen
The antigen is digested into molecular fragments, the rest is expelled via exocytosis
The fragments are displayed in the grooves of the MHC proteins
74
T cell communication with APCs
Wandering T cells inspect APCs for displayed antigens
If there is only a self-antigen present, the T cells ignore the APC
If the APC displays a foreign antigen, the T cell initiates an immune attack
75
Types of T cells (4)
Cytotoxic T cells (Tc)
Helper T cells (Th)
Regulatory T cells (Tr)
Memory T cells (Tm)
76
Cytotoxic T Cells
Killer T cells (NOT NKCs) that carry out the attack on foreign cells
77
Helper T Cells
Promote the action of Tc & B cells and play key roles in humoral and innate immunity
78
Regulatory T Cells
Limit the immune response by inhibiting multiplication and cytokine secretion by other T cells
After defeating a pathogen, Tr cells down-regulate Tc activity, otherwise inflammation would remain
79
Memory T Cells
Descended from Tc cells and are responsible for memory in cellular immunity
80
Adaptive Defense
An APC digests and presents an antigen
Th (CD4) cells contact the APC and clones into memory CD4 cells and helper cells
Helper cells, with co-stimulation, activate Tc (CD8) cells
Tc cells clone to produce memory Tc cells and activated Tc cells
Helper cells, when stimulated by cytokines, produce nonspecific killers (macrophages and NKCs)
81
Stages of Adaptive Defense
Recognition: APCs encounter and process antigens, presenting them to T cells. The T cells are activated and they undergo repeated mitosis (clonal selection)
Attack: Th cells are necessary as they coordinate both humoral and cellular immunity. Tc cells "dock: on the MHC protein of a foreign cell and deliver lethal doses of chemicals to kill them
Memory: Following clonal selection, some Tc and Th cells become memory cells that have long life spans
82
Humoral Immunity
An indirect method of defense where B lymphocytes produce antibodies that bind to antigens, tagging them for destruction by other means
83
Primary vs Secondary Humoral Response
Primary Response: The first time a virus is presented and fought off by the body, IgM antibodies are produced first, then IgG antibodies are produced shortly after but in a larger quantity.
Secondary Response: A later presentation of the same virus results in both IgG and IgM antibodies being produced, though IgG production is still greater
84
Stages of Humoral Immunity
Recognition: An antigen binds to several receptors on a B cell, linking them together. The antigen is then taken into the cell and digested.
Attack: B cells produce antibodies for the digested antigen and release them, leading to one of four mechanisms to render the antigen harmless.
Memory: The primary response occurs the first time an antigen is presented, resulting in the B cell cloning itself. During clonal selection, some cloned cells become memory cells instead of plasma cells.
85
How to B Lymphocytes produce Antibodies?
B cells become plasma cells, which have lots of rough ER. The ribosomes of the rough ER are used to make antibodies.
86
Humoral Attack Mechanisms (4)
Neutralization
Complement Fixation
Agglutination
Precipitation
87
Humoral Neutralization
Antibodies bind to the surface of the antigen, covering it and preventing it from binding and infecting other cells
Enhances phagocytosis
88
Humoral Complement Fixation
An action in which antibodies bind complement proteins to an enemy cell, leading to its destruction via lysis
Enhances phagocytosis and inflammation
89
Humoral Agglutination
Antibodies effectively clump multiple antigens together
Enhances phagocytosis
90
Humoral Precipitation
Antigen molecules are clumped together via adhesion to antibodies. Similar to agglutination, however these antigens are more like a chain than a clump
Enhances phagocytosis
91
Hypersensitivity Immune Disorder
An excessive immune reaction against antigens that most people tolerate.
Alloimmunity: Reaction to transplanted tissue from another person
Autoimmunity: Abnormal reactions to one's own tissues
Allergies: Reactions to environmental antigens
92
Reasons why Autoimmune Diseases fail self-tolerance? (3)
Cross Reactivity: Some antibodies made for foreign antigens react similar to self-antigens
Abnormal Exposure of self-antigens to blood: Some of our native antigens are not normally exposed to blood
Change in the structure of self-antigens: Viruses and drugs may change the structure of self-antigens or cause the immune system to perceive them as foreign
93
Functions of the Respiratory System (8)
Gas Exchange
Communication
Olfaction/Smell
Acid-Base Balance
Blood Pressure Regulation
Platelet Production
Blood & Lymph Flow
Blood Filtration
Expulsion of Abdominal Content
94
Valsalva Maneuver
Closing the glottis and contracting the muscles of the abdomen when trying to produce more force (urination, defecation, childbirth, vomiting)
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Conducting Zone
Areas of the Respiratory System where air flows freely
96
Respiratory Zone
Areas of the Respiratory System where gas exchange occurs
97
Functions of the Nasal Region of the Upper Respiratory Tract
Warms, cleanses, and humidifies inhaled air. Also detects odors and amplifies the voice.
98
How is air warmed in the nasal region?
Blood vessels are very close to the surface, allowing for better heat transfer
99
Where is the Olfactory Epithelium located?
It lines only the superior portion of the nasal conchae
100
What is the purpose of the nasal cavity?
The nasal cavity serves to collect debris and prevent it from entering the respiratory tract. The narrowness of the L & R cavities, along with the turbulence of the airflow ensures surface area contact
101
What is the primary function of the Larynx?
It keeps food and drink out of the airway via the epiglottis. It also plays a role in sound production via the "voice box"
102
What is the Glottis?
A slit between the larynx and trachea that houses vestibular and vocal folds
103
Vestibular Folds
Musculature that opens and closes the glottis
104
Vocal Folds
AKA Vocal Cords, they help to close the glottis when contracted
As air flows through the folds, it produces sounds for vocalization which are then modified by the pharynx
105
Male vs. Female Vocal Cords
Male voices are deeper because the glottis and folds are longer and thicker
The cords vibrate more slowly, producing lower-pitched sounds
106
What is the Mucociliary Escalator?
Cilia on the trachea epithelium moves mucus upward past the epiglottis so that it can be swallowed
107
Why does smoker's cough occur?
The cilia on the trachea have disappeared or been damaged by smoking, meaning that mucus cannot be pulled upward and must be coughed up.
108
Bronchial Tree
The trachea divides into left and right MAIN BRONCHI.
The main bronchi then divide further into BRONCHIOLES
109
Bronchioles
The smallest bronchi at the end of the conducting zone
110
Alveoli
A cluster of small alveolus pouches that are porous and directly exchange air with each other. They are surrounded to and connected to the pulmonary capillary beds
111
Squamous (Type I) Alveolar Cells
Cover 95% of the alveolar surface area, allowing for rapid gas diffusion and connecting them to the capillary bed
112
Great (Type II) Alveolar Cells
Covers the other 5% and repairs the alveolar epithelium when type I cells are damaged. They secrete pulmonary surfactant
113
Pulmonary Surfactant
Fluid secreted by type II alveolar cells that breaks the bonds between water molecules, reducing the cohesion/attraction between them. This helps the thin, watery membranes within the alveoli to stretch during inhalation
114
Alveolar Macrophages (Dust Cells)
The most numerous of all lung cells, they wander the lumens of alveoli and the connective tissues between them, phagocytizing dust particles
115
Respiratory Membrane
The layers of alveolar and blood vessel tissues where gas exchange occurs between the two
116
Why and how are the alveoli kept dry?
Gases diffuse too slowly through liquids
Alveoli are kept dry by the absorption of excess liquid by blood capillaries
Lungs have more lymphatic drainage than any other organ
117
How is respiratory airflow related to pressure and resistance?
Airflow is directly proportional to pressure differences between two places
Airflow is inversely proportional to resistance
118
What pressure drives respiration?
Atmospheric Pressure
760 mmHg = 1 atm
119
Boyle's Law
Volume decreases as Pressure increases
At a constant Temperature
120
Intrapulmonary Pressure
The pressure within the lungs. It is ALWAYS greater than intrapleural pressure
121
Intrapleural Pressure
The pressure outside of the lungs in the pleural cavity. This is NEGATIVE pressure
122
Transpulmonary Pressure
The difference between Intrapulmonary and Intrapleural pressures
123
Factors influencing airway resistance (2)
Diameter of Bronchioles
Pulmonary Compliance
124
What causes bronchodilation?
Epinephrine and the Sympathetic Nervous System
125
What causes bronchoconstriction?
Histamine, the Parasympathetic Nervous System, cold air, and other irritants
126
Pulmonary Compliance
The ease with which the lungs can expand
Compliance is reduced by degenerative lung disease in which the lungs are stiffened by scar tissue
127
Tidal Volume
The volume of air inhaled and exhaled in one cycle of breathing
Average = 500 mL
128
Inspiratory Reserve Volume
The excess air that can be inhaled after tidal volume with maximum effort
Average = 3,000 mL
129
Expiratory Reserve Volume
Air in excess of tidal volume that can be exhaled with maximum effort
Average = 1,200 mL
130
Residual Volume
The volume of air still in the lungs after fully forcing as much air out as possible
131
Visceral Pleura
Pleural layer that covers the lungs and extends into the fissures of the lungs
132
Parietal Pleura
Pleural layer that adheres to the mediastinum, inner rib cage, and superior surface of the diaphragm
133
Pleural Cavity
The space between the lungs and the ribcage that is filled with pleural fluid, reducing friction
134
Anatomical Dead Space
The area of the conducting zone that holds inhaled air. This air does not reach the alveoli and the gases within are not exchanged.
135
Physiological (Total) Dead Space
The sum of anatomical dead space and any pathological dead space that exists
136
Alveolar Ventilation Rate
The volume of air that ventilates the alveoli multiplied by breaths/minute
137
Henry's Law
Increasing the partial pressure of a gas will make it more soluble
138
Partial Pressure
The pressure of one gas in the air. The sum of all partial pressures adds up to atmospheric pressure
139
Ventilation-Perfusion Coupling
Blood flow matches airflow and vice versa.
When airflow decreases, the partial pressure of O2 in the blood vessels decreases resulting in vasoconstriction of the pulmonary vessels, decreasing blood flow.
When blood flow decreases, the partial pressure of CO2 in the alveoli is reduced causing constriction of the bronchioles and decreasing airflow.
140
Variables that affect the efficiency of alveolar gas exchange
Pressure gradients from gases
Solubility of gases
Membrane thickness
Membrane area
Ventilation-perfusion coupling
141
How does transportation occur at the capillary-alveolar barrier?
Oxygen from the alveoli enter the bloodstream in large quantities, binding to Hb which in turn releases H+ ions.
The H+ ions then bind to HCO3- (bicarbonate) to make H2CO3. This molecule then splits into H2O and CO2, which enters the alveoli to be exhaled.
142
How does transportation occur at the capillary-tissue barrier?
CO2 is released from the tissues and into the bloodstream where it combines with H2O to make H2CO3. This molecule then releases an H+ ion which binds to HbO2, causing it to release O2 for use in the tissues.
143
How is CO2 transported in the blood?
Primarily in the form of carbonic acid
5% bound to proteins
5% dissolved as a gas in the plasma
144
What factors adjust the rate of O2 unloading?
Ambient PO2 - Active tissues have lower PO2, so O2 is released from Hb
Ambient pH - Active tissues have more CO2, lowering pH and promoting O2 unloading
Biphosphoglycerate
Temperature - Active tissues have a higher temperature, promoting O2 unloading because proteins unfold at higher temps
