Lymphatic/Immune/Respiratory Flashcards
(454 cards)
1
Q
what is the lymphatic system composed of?
A
lymphatic tissues and organs
2
Q
what is lymph?
A
the fluid transported within lymph vessels
3
Q
where does lymph originate?
A
as interstitial fluid surrounding tissue cells
4
Q
how does lymph move into lymphatic capillaries?
A
passively due to pressure gradient
5
Q
How much fluid entering interstitial space from capillaries does not reabsorb?
A
15% ~ about 3 liters a day
6
Q
when does interstitial fluid become lymph?
A
when it enters the lymph vessels
7
Q
what are the components of lymph?
A
water dissolved solutes small amount of protein sometimes foreign material (cell debris, pathogens & maybe metastasized cancer cells)
8
Q
what are the smallest lymph vessels?
A
lymphatic capillaries
9
Q
describe lymphatic capillaries
A
microscopic, closed-ended vessels that absorb interstitial fluid interspersed throughout areolar connective tissue among most blood capillary networks (except in red bone marrow and nervous system) absent within avascular tissues like epithelia
10
Q
what are the similarities and differences between blood capillaries and lymph capillaries?
A
walls of both are composed of endothelium lymphatic capillaries are larger in diameter than blood capillaries lymphatic capillaries don’t have basement membrane & they have overlapping endothelial cells
11
Q
how do overlapping endothelial cells function in lymphatic capillaries?
A
act as 1-way flap to let fluid enter but not exit
12
Q
what are anchoring filaments?
A
help hold lymphatic capillary endothelial cells to nearby structures
13
Q
what holds lymphatic capillaries to nearby structures?
A
anchoring filaments
14
Q
what are lymphatic capillaries located in the GI tract called?
A
lacteals
15
Q
what is the force that moves fluid into lymphatic capillaries?
A
hydrostatic pressure within the interstitial space
16
Q
what prevents lymphatic capillary collapse as interstitial fluid pressure increases?
A
anchoring filaments
17
Q
what do lymphatic capillaries merge to form?
A
lymphatic vessels
18
Q
describe lymphatic vessels
A
resemble small veins have 3 vessel tunics (intima, media and externa), and have valves within lumen to prevent lymph backflow & pooling
19
Q
where are lymphatic vessels found?
A
superficial lymphatic vessels are usually adjacent to superficial veins deep lymphatic vessels are next to deep arteries and veins
20
Q
what mechanisms move lymph through the vessels?
A
- contraction of nearby skeletal muscles in the limbs & respiratory pump 2. pulsatile movement of blood in nearby arteries 3. rhythmic contraction of smooth muscle in walls of larger lymph vessels (trunks and ducts)
21
Q
what are lymphatic organs called?
A
lymph nodes
22
Q
where to lymphatic vessels go?
A
some go to lymph nodes, some feed into lymphatic trunks on bht right and left side of the body
23
Q
name the lymphatic trunks
A
jugular trunks subclavian trunks bronchomediastinal trunks intestinal trunks lumbar trunks
24
Q
what does each trunk drain?
A
jugular - head and neck subclavian - upper limbs bronchomediastinal - deep thoracic structures intestinal - most abdominal structures lumbar - lower limbs, abdominopelvic wall & pelvic organs
25
what do lymphatic trunks drain into?
lymphatic ducts (the largest lymph vessels)
26
how many lymphatic ducts are there?
2
27
name the lymphatic ducts
right lymphatic duct thoracic ducts
28
what do lymphatic ducts do?
convey lymph back into venous blood circulation
29
what is lymphedema?
swelling - an accumulation of interstitial fluid due to interference with lymphatic drainage in a part of the body
30
where is the right lymphatic duct?
near the right clavicle
31
what does the right lymphatic duct drain?
right side of the head and neck right upper limb right side of the thorax
32
where does the right lymphatic duct return fluid?
junction of the right subclavian vein and the right internal jugular vein
33
which lymphatic duct is the largest?
the thoracic duct
34
how big is the thoracic duct?
15-18 inches
35
where is the thoracic duct?
extends from the diaphragm inferiorly to junction of the left subclavian and left jugular veins superiorly
36
what does the thoracic duct drain?
left side of head and neck, left upper limb, left thorax, all of the abdomen and both lower limbs
37
what & where is the cisterna chyli?
saclike structure at the base of the thoracic duct and anterior to the L2 vertebra
38
what is chyle?
milky, lipid-rich lymph that drains from the small intestine and the GI tract
39
which trunks drain into the cisterna chyli?
left and right intestinal and lumbar trunks
40
What tissues and organs are lymphatic structures?
red bone marrow thymus lymph nodes spleen tonsils MALT (mucosa-associated lymphatic tissue) and diffuse lymphatic nodules
41
how are lymphatic system tissues and organs categorized?
as either primary (involved in formation & maturation of lymphocytes) or secondary (house lymphocytes & other immune cells following their formation - provide the site where an immune response is initiated)
42
what are the primary lymphatic structures?
red bone marrow & thymus
43
what are the major secondary lymphatic structures?
lymph nodes, spleen, tonsils, lymphatic nodules and MALT
44
where is red bone marrow located?
spaces between trabeculae in spongy bone in adults --\> flat bones of skull, vertebrae, ribs, sternum, ossa coxae, proximal epiphyses of each humerus and femur
45
what is the function of red bone marrow?
formation of all formed elements (hemopoiesis) (erythrocytes, platelets, granulocytes (neutrophils, eosinophils, and basophils), agranulocytes (monocytes and lymphocytes)
46
where is the thymus located?
superior mediastinum (in adults); anterior and superior mediastinum (in children)
47
what is the function of the thymus?
site of T-lymphocyte maturation and differentiation
48
where are the lymph nodes located?
along the length of lymphatic vessels; clusters are present in axillary, inguinal and cervical regions
49
what is the purpose of lymph nodes?
filter lymph; where immune response is initiated against a substance in the lymph
50
where is the spleen located?
left upper quadrant of abdomen, near 9h -11th ribs, wraps partway around stomach
51
what is the function of the spleen?
filters blood; where immune response is initiated against a substance in the blood; removes aged erythrocytes and platelets; serves as platelet reservoir
52
where are the tonsils located?
within pharynx (throat)
53
what is the function of the tonsils?
protect against inhaled and ingested substances
54
where is MALT located?
within the walls of the gastrointestinal tract, respiratory, reproductive, and urinary tracts
55
what is the function of MALT?
initiates an immune response against a substance that comes in contact with a mucosal membrane
56
what are the 2 major types of lymphocytes?
T-lymphocytes (T-cells) B-lymphocytes (B-cells)
57
where do t-lymphocytes complete their maturation?
in the thymus
58
how long does the thymus grow?
until puberty - maximum weight is 30-50 grams
59
what happens to the thymus after puberty?
cells begin to regress - replaced by adipose tissue
60
describe the thymus
2 fused lobes (thymic lobes) - each surrounded by a connective tissue capsule. trabeculae (fibrous extensions of capsule) subdivide lobes into lobules each lobule has outer cortex and inner medulla, both parts composed primarily of epithelial tissue infiltrated with T-lymphocytes in varying stages of maturation cortex has immature T-lymphocytes medulla has mature T-lymphocytes
61
what do epithelial cells of thymus secrete?
thymic hormones that participate in maturation of T-lymphocytes
62
what kind of organ is the thymus?
a lymphoepithelial organ - it has both lymphatic cells and epithelial tissue
63
what are secondary lymphatic structures?
structures that house lymphocytes and other immune cells
64
what kinds of structures are secondary lymphatic structures?
lymphatic organs or aggregates of lymphatic nodules
65
what is the difference between a lymphatic organ and an aggregate of lymphatic nodules?
presence or absence of a capsule composed of dense irregular connective tissue lymphatic organs have a complete capsule other lymphatic structures either have no capsule or an incomplete capsule
66
what are the secondary lymphatic organs?
spleen and lymph nodes
67
what are the secondary lymphatic nodules?
tonsils, MALT, diffuse lymphatic nodules
68
what are lymph nodes?
small, round or oval encapsulated structures located along the pathways of lymph vessels
69
what do lymph nodes do?
filter lymph and remove unwanted substances
70
what kinds of cells migrate from skin and mucosal membranes to a lymph node following endocytosis of foreign substances?
dendritic cells phagocytic cells that are formed in bone marrow & housed in epithelial tissue of skin & mucosal membranes
71
where are clusters of lymph nodes?
axillary (armpit) inguinal (groin) cervical
72
where do axillary lymph nodes receive lymph from?
breast, axilla, & upper limb
73
where do inguinal lymph nodes receive lymph from?
lower limb & pelvis
74
where do cervical lymph nodes receive lymph from?
head & neck
75
what are afferent lymphatic vessels?
bring lymph into a lymph node
76
what is an efferent lymphatic vessel?
drains lymph from the lymph node
77
What does pathogenic mean?
infectious agents that cause harm to the host
78
what are the 5 categories of infectious agents?
bacteria, viruses, fungi, protozoans, and multicellular parasites (and prions)
79
what is virulence?
the ability to cause serious illness
80
what are the characteristics of bacteria?
prokaryotic intracellular & extracellular parasites; some produce enzymes, toxins
81
what are the characteristics of viruses?
not a cell; DNA or RNA is within a capsid protein obligate intracellular parasite; must enter a cell to replicate
82
what are the characteristics of fungi?
they are eukaryotic produce spores; release proteolytic enzymes
83
What are characteristics of protozoans?
they are eukaryotic intracellular and extracellular parasites that interfere with normal cellular functions
84
what are characteristics of multicellular parasites?
eukaryotic live within a host; grow in size with nutrients provided by the host
85
what are the 2 components of the immune system?
innate and adaptive
86
where are leukocytes formed?
in the red bone marrow
87
what are the different leukocytes?
1) 3 types of granulocytes (neutrophils, eosinophils, basophils) 2) monocytes (become macrophages when they exit blood vessels) 3) 3 types of lymphocytes (T-lymphocytes, B-lymphocytes, NK (natural killer) cells)
88
what are the primary locations that house immune cells?
lymphatic tissue select organs epithelial layers of the skin and mucosal membranes connective tissue
89
what immune cells are housed in lymphatic tissue?
t-cells, b-cells, macrophages, and NK cells housed in 2ndary structures of lymph nodes, spleen, tonsils, MALT & lymphatic nodules
90
what kind of immune cells are housed in select organs?
macrophages some named based on location (alveolar macrophages of lungs, microglia of brain) can be fixed or wandering
91
what kind of immune cells are located in epithelial layers of the skin and mucosal membranes?
dendritic cells (derived from monocytes) in skin, they are called epidermal dendritic cells
92
what kind of immune cells are located in connective tissue?
mast cells (similar to basophils) usually close to small blood vessels especially abundant in dermis of skin, mucosal linings of respiratory, digestive & urogentical tracts also housed in CT of organs
93
what are cytokines?
small soluble proteins produced by cells of innate & adaptive immune system - regulate and facilitate immune system activity serve as means of communication between cells control development and behavior of effector cells of immunity regulate inflammatory response of innate immunity sometimes serve as weapons to destroy cells
94
how does a cytokine work?
released from 1 cell & binds to receptor on target cell
95
what kinds of cells can cytokines act on?
the cell that released it (autocrine) a neighboring cell (paracrine) circulate in blood system to cause systemic effects (endocrine)
96
what is the length of a cytokine half life?
short - to prevent continuous stimulation
97
what are the major classes of cytokines?
interleukin - regulates immune cells tumor necrosis factor - destroys tumor cells colony-stimulating factor - stimulates leukopoiesis in bone marrow to increase synthesis of a specific type of leukocyte interferon - IFN-alpha & IFN-beta are antiviral agents. IFN-gamma is pro-inflammatory agent
98
what are the two categories of immunity?
innate and adaptive
99
what is the body's first line of defense?
skin and mucosal membranes
100
what is the body's second line of defense?
internal processes of innate immunity 1) activities of various types of cells (neutrophils, macrophages, NK cells) 2) chemicals like interferon and complement 3) physiological processes including inflammatory response & fever
101
what parts of the skin prevent entry of pathogens?
epidermis/dermis (physical, chemical & biological barrier) normal flora (helps prevent growth of pathogenic microbes) exfoliation (removes potential pathogens from skin surface) hyaluronic acid (located in areolar tissue of the dermis - slows migration of microbes that have penetrated the epidermis) sebaceous (oil) gland secretions - contain lactic & fatty acids (create a low pH (3-5) - interferes with growth of microbes sweat gland secretions - contain lysozyme, defensins & dermicidin (helps wash away microbes, contains antibacterial & antifungal substances)
102
How do the mucous membranes prevent entry of pathogens?
epithelial & connective tissue - lining of respiratory, GI & urogenital tracts (provides physical, chemical, & biological barrier) normal flora - helps prevent growth of pathogenic microbes mucus - secretion containing lysozyme, defensins & IgA (thick secretion that helps trap microbes; contains antimicrobial substances)
103
how does the respiratory tract prevent entry of pathogens?
nasal secretions - contain lysozyme, defensins & IgA - contain antimicrobial substances vibrissiae - hairs in nasal cavity (traps microbes in the nose) cilia - extensions of plasma membrane (sweeps mucus upward to that it can be expectorated or swallowed coughing & sneezing (mechanical elimination of microbes or other foreign substances from respiratory tract)
104
How does the gastrointestinal tract prevent entry of pathogens?
saliva - secretions released into mouth from salivary glands - contain lysozyme & IgA (helps wash away microbes; contains antimicrobial substances) hydrochloric acid - produced within stomach (creates very low pH (~2) that destroys many bacteria, bacterial toxins & other microbes that enter stomach defecation & vomiting - removal of waste from digestive tract (eliminates microbes before they can be absorbed into the blood)
105
how does the urogenital tract prevent entry of pathogens?
urine (flow of urine flushes microbes from urinary tract) lactic acid - weak acid (produced by vagina, creates low pH that slows or prevents growth of microbes
106
how do secretions produced by the skin & mucous membranes prevent entry of pathogens?
lysosome - antibacterial enzyme (attacks cell wall of gram + bacteria) defensins - small proteins (create pores in the plasma membrane of microbes compromising their integrity) demicidin - small proteins produced by the skin (antibacterial agent against gram + and gram - bacteria, antifungal agent) Immunoglobulin A (IgA) - specific type of antibody present in areas exposed to the environment (binds with a specific foreign substance (antigen))
107
how do other secretions prevent entry of pathogens?
lacrimal fluid - fluid produced by lacrimal glands (by eye - tears) contains lysozyme & IgA (washes microbes away from surface of eyes; contains antimicrobial agents) cerumen - waxy secretions within external auditory meatus (waterproofs external auditory meatus; may trap microbes in external ear)
108
what is the third line of defense?
adaptive immunity
109
What cells are involved in innate immunity?
neutrophils, macrophages, basophils, mast cells, NK cells & eosinophils
110
how do neutrophils & macrophages function in innate immunity?
neutrophils - most prevalent leukocyte in blood. 1st to arrive during inflammatory response macrophages - reside in tissues throughout body - arrive later than neutrophils & stay longer both engulf unwanted substances through phagocytosis. phagosome (vesicle w/stuff) merges with lysosome --\> phagolysosome --\> enzymes digest unwanted stuff w/help from r O containing molecules like H2O2 --\> residue released from the cell by exocytosis
111
How do basophils and mast cells function in innate immunity?
both are proinflammatory chemical-secreting cells basophils circulate in blood, mast cells reside in connective tissue of skin, mucosal linings & internal organs secretions increase fluid movement from the blood to an injured tissue & serve as chemotactic chemicals (attract immune cells as part of inflammatory response) both release granules --\> contain histamine (increases vasodilation & capillary permeability) and heparin (anticoagulant) and eicosanoids (from plasma membrane - increase inflammation)
112
what does histamine do?
increases vasodilation and capillary permeability
113
what does heparin do?
anticoagulant
114
what do natural killer cells do?
destroy unwanted cells (virus-infected, bacteria-infected, tumor cells & transplanted tissue cells) formed in bone marrow, circulate in blood, accumulate in secondary lymphatic structures of lymph node, tonsils, & spleen immune surveillance (patrol body) - make physical contact w/unhealthy cells & release cytotoxic chemicals: perforin (forms transmembrane pore) and granzymes (enter through pore & initiate apoptosis)
115
what is apoptosis?
cellular death - involves shriveling rather than lysing - limits spread of infectious agent
116
what do eosinophils do?
target parasites - destroy by degranulation, releasing of enzymes & other substances that are lethal to parasite, & can release proteins that form transmembrane pore (like NK cells) participate in immune response associated with allergy and asthma & engage in phagocytosis of antigen-antibody complexes
117
what are two kinds of antimicrobial proteins?
interferon and complement
118
what are interferons?
IFN class of cytokines released from many different kinds of cells (leukocytes & fibroblasts are two) - released by virus-infected cell
119
what are the actions of interferon?
-binds to receptors of neighboring cells, preventing infection - triggers synthesis of enzymes that destroy viral RNA or DNA & inhibit synthesis of viral proteins -stimulates macrophages and NK cells to destroy virus-infected cells
120
what is complement?
30 plasma proteins (at least) make up about 10% of serum proteins in blood - antimicrobial group of substances
121
what synthesizes complement proteins?
liver - continually makes & releases inactive complement proteins into the blood
122
how are complement proteins activated?
by an enzyme cascade in the blood
123
when are complement proteins activated?
when a pathogen enters the body via classical pathway (complement protein binds to an antibody that has previously attached to a foreign substance) or the alternative pathway (surface polysaccharides of bacterial and fungal cell walls bind directly with complement protein)
124
what mechanisms does the complement system use to protect the body?
opsonization inflammation cytolysis elimination of immune complexes
125
what is opsonization?
binding of protein to a portion of bacteria or other cell type that enhances phagocytosis. - binding protein is opsonin
126
how does complement enhance inflammatory response?
activation of mast cells and basophils and by attracting neutrophils and macrophages
127
how does the complement system perform cytolysis?
trigger direct killing by forming a protein channel in plasma membrane (membrane attack complex MAC) allowing influx of fluid causing cell lysis
128
How does the complement system mediate elimination of immune complexes?
links antigen-antibody complexes (immune complexes) to erythrocytes so they can be transported to liver and spleen where macrophages strip the complexes from erythrocytes.
129
what is the inflammatory response?
an immediate, local, nonspecific event that occurs in vascularized tissue against great variety of injury causing stimuli
130
what is the major innate immune effector response?
the inflammatory response
131
what are the events of inflammation?
1. release of inflammatory and chemotactic factors 2. vascular changes (vasodilation, increase in capillary permeability, display of CAMs) 3. recruitment of immune cells (margination, diapedesis, chemotaxis) 4. delivery of plasma proteins
132
what are the chemicals of inflammation?
histamine bradykinin leukotrienes prostaglandins chemotactic factor serotonin nitric oxide alpha-1 antitrypsin C-reactive protein
133
describe function and source of histamine in the inflammatory response
vasodilation, increased permeability of capillaries, conversion of an inactive plasma protein (kininogen) into active peptides called kinins, released early in inflammation from mast cells, basophils and platelets
134
describe function and source of bradykinin in inflammatory response
vasodilation & increased permeability of capillaries, stimulates sensory pain receptors comes from plasma protein produced by the liver and other cells as kininogen; activated by tissue injury
135
describe function and source of leukotrienes in inflammatory response
effects are similar to histamine, released later in the inflammatory response than histamine & longer lasting source: eicosanoids produced from arachidonic acid molecules of mast cell plasma membranes
136
describe function and source of prostaglandins in inflammatory response
vasodilation, fever, stimulates sensory pain receptors source: eicosanoids produced from arachidonic acid molecules of mast cell plasma membranes
137
describe function and source of chemotactic factor in the inflammatory response
attracts immune cells, release of specific chemotactic factors attract a specific type of cell (i.e. neutrophil chemotactic factor, eosinophil chemotactic factor...) source: mast cells
138
describe the function and source of serotonin in the inflammatory response
similar to histamine: vasodilation, increased capillary permeability source: platelets
139
describe the function and source of nitric oxide in the inflammatory response
vasodilation, may inhibit mast cells and platelets source: endothelium of blood vessels
140
describe the function and source of alpha-1 antitrypsin in the inflammatory response
inhibits damage to connective tissue by enzymes released from destroyed phagocytes source; plasma protein formed by the liver
141
describe the function and source of C-reactive protein in the inflammatory response
activates complement by binding to polysaccharides on bacteria surface source: liver
142
what are CAMs?
cell-adhesion molecules chemicals stimulate capillary endothelium to provide molecules for leukocyte adhesion.
143
How do leukocytes make their way from blood to infected tissue?
margination (CAMs on leukocytes adhere to CAMs on endothelial walls of capillaries - velcro) diapedesis (cells exit blood by squeezing between vessel wall cells) chemotaxis (migration of cells along a chemical gradient - released from damaged cells)
144
what plasma proteins are brought to site of injury during inflammatory response?
immunoglobulins, complement, clotting proteins & kinins
145
what is exudate?
an effect of inflammation net movement of fluid from blood through infected or injured area then into lymph - increased fluid, protein and immune cells leaving capillaries and entering interstitial space - delivers cells & substances needed to eliminate the injurious agent & promote healing
146
How is exudate like washing?
increased hydrostatic pressure from fluid going to injury site, makes lymph system take up more lymph that carries with it infectious agents, dead cells, and cellular debris - monitored as it passes through lymph nodes
147
how long does the inflammatory response usually last?
usually slows & healing begins within 72 hours. usually lasts no longer than 8-10 days (acute inflammatory response)
148
what are the cardinal signs of inflammation?
redness (increased blood flow) heat (increased blood flow & increased metabolic activity in the area) swelling (increased fluid loss from capillaries into interstitial space) pain (stimulation of pain receptors from compression & chemical irritation by kinins, prostaglandin & substances released by microbes) loss of function
149
what is pyrexia?
fever - abnormal elevation of body temperature of at least 1degree C
150
what are pyrogens?
interleukin 1, interferons, toxins produced by infectious agents (fever producing substances)
151
what do pyrogens target?
hypothalamus
152
what do pyrogens do?
target hypothalamus --\> causes release of prostaglandin E2 --\> raises temperature set point of hypothalamus
153
what are the stages of fever?
onset stadium defervescence (can be cyclical until pathogen is eliminated or controlled)
154
what happens during onset of fever?
hypothalamus stimulates blood vessel vasoconstriction in dermis of skin to decrease heat loss. person shivers to increase heat production through muscle contraction body temperature rises person may experience chills ---\> shivering
155
what happens during fever stadium?
elevated temperature is maintained. Metabolic rate increases. liver and spleen bind zinc and iron (minerals needed by microbes) to slow microbial reproduction.
156
what happens during fever defervescence?
temperature returns to its normal set point. hypothalamus no longer stimulated by pyrogens, prostaglandin release decreases. hypothalamus stimulates mechanisms to release heat from body --\> vasodilation of blood vessels in skin and sweating. person may be flushed & skin warm to touch.
157
what are the benefits of fever?
inhibits reproduction of bacteria and viruses, promotes interferon activity, increases activity of adaptive immunity, accelerates tissue repair
158
when is a fever significant?
when it is above 100 degrees
159
what constitutes chronic inflammation?
when it continues for longer than 2 weeks.
160
what is the difference between acute inflammation and chronic inflammation?
acute is characterized by neutrophil presence, chronic is characterized by cells that arrive later, like macrophages and lymphocytes
161
what are risks of high fever?
changes in metabolic pathways and denaturation of body proteins may occur seizures may occur at sustained temperatures above 102 irreversible brain damage with sustained temps above 106, and death likely when temp reaches 109.
162
what is the difference between the first line of defense and the second line of defense in innate immunity?
first line - preventing entry of infectious agents second line - nonspecific cellular and molecular defenses for protecting the body (fever, inflammation)
163
which response is faster, innate or adaptive immunity?
innate immunity
164
what is the immune response?
lymphocytes formed and products they secrete in the body's defense after contact with an antigen.
165
how long does it take to develop and immune response?
several days
166
what is the body's third line of defense?
adaptive immunity
167
what are the two types of immune response?
cell-mediated immunity (response involving T-lymphocytes) humoral immunity (response involving B-lymphocytes that develop into plasma cells to synthesize and release antibodies)
168
compare cell-mediated immunity with humoral immunity
cell-mediated: T-lymphocyte effective against antigen within cells requires an antigen-presenting cell humoral B-lymphocyte effective against antigen outside of cells does not require antigen-presenting cells
169
what is the molecular structure of an antigen?
usually a protein or a large polysaccharide i.e. parts of infectious agents like protein capsid of viruses, cell wall of bacteria or fungi, bacterial toxins, tumor antigens
170
what is an antigenic determinant?
specific portion of an antigen to which the components of the adaptive immune system bind. - typically, each antigen has several antigenic determinants.
171
what is an autoimmune disorder?
when the body's immune system reacts to self-antigens as if they were foreign
172
what happens to foreign antigens?
they bind with the body's immune components because they are different in structure from the body's own molecules
173
what is another name for antigenic determinant?
epitope
174
what is an immunogen?
an antigen that induces an immune response
175
what is immunogenicity?
the ability to cause an immune response
176
what is a hapten?
a substance that is too small to function as an antigen alone, but when attached to a carrier molecule in a host, then they become antigenic
177
how do T-lymphocytes & B-lymphocytes differ from other immune cells?
they have a receptor complex (about 100,000 per cell) - each complex will bind with one specific antigen
178
what is a TCR and a BCR?
t-cell receptor - antigen receptor of a t-lymphocyte and b-cell receptor - antigen receptor of a b-lymphocyte
179
which lymphocyte can make direct contact with an antigen?
b-lymphocytes
180
what do t-lymphocytes have that B-lymphocytes do not?
additional receptor molecules called co-receptors facilitate interaction with a cell presenting antigen
181
what are the 2 major types of t-lymphocytes?
helper t-lymphocytes and cytotoxic t-lymphocytes
182
what are CD molecules?
a category of coreceptor on t-lymphocytes
183
how can helper t-lymphocytes be distinguished between cytotoxic t-lymphocytes based on coreptors?
plasma membranes of helper t-lymphocytes contain CD4 protein plasma membranes of cytotoxic t-lymphocytes contain CD8 protein
184
What is the difference between helper t-lymphocytes and cytotoxic t-lymphocytes?
helper t-lymphocytes help activate B-lymphocytes - also called CD4+ or CD4 cells cytotoxic t-lymphocytes release chemicals that are toxic to cells - also called CD8+ or CD8 cells
185
what categories of cells present antigens to t-lymphocytes?
all nucleated cells of the body and antigen-presenting cells (APC)
186
what does antigen-presenting cell refer to?
any immune cell that functions specifically to communicate the presence of antigen to both helper t-lymphocytes and cytotoxic t-lymphocytes dendritic cells macrophages B-lymphocytes all function as APCs
187
what is an MHC?
major histocompatibility complex a transmembrane protein where an antigen physically is attached
188
what is the difference between MHC class I molecules and MHC class II molecules?
all nucleated cells present antigen with MHC I molecules APCs display antigen with both MHCI and MHCII molecules MHCII are only displayed by antigen-presenting cells
189
what is an MHC class I molecule?
a glycoprotein
190
describe the formation and docking of MHC Class I molecules in nucleated cells
Healthy cell: MHC class I molecules synthesized by RER. peptide fragments of the cell bind with MHC class I molecules. (2) transport vesicles produced from RER contain MHCI with bound self-antigen shipped by endomembrane system through Golgi apparatus to plasma membrane (3) MHCI molecules bound with self-antigen displayed within plasma membrane unhealthy cell: (1) MHCI molecules synthesized by RER along with peptide fragments of foreign antigen that become attached (instead of healthy self fragments) (2) transport vesicles produced from RER contain MHCI molecules attached to viral peptide fragments - shipped by endomembrane system through Golgi apparatus to plasma membrane (3) MHCI with bound foreign antigen displayed within plasma membrane
191
what happens when MHCI molecules display foreign antigen?
alerts cytotoxic T-lymphocytes that cell should be destroyed
192
how does an MHCII molecule display on an antigen-presenting cell?
like MHCI, continuously synthesized b RER, modified by endomembrane system & embedded w/in plasma membrane. when APC engulfs exogenous antigens (pathogens, cellular debris or other harmful substances located outside the cell), a phagosome (vesicle) is formed. phagosome merges with lysosome to form phagolysosome. Substance digested into peptide fragments. Vesicle w/peptide fragments (antigens) merges with vesicles containing MHCII molecules. peptide fragments loaded into MHCII molecules. then vesicles merge with plasma membrane of APC ---\> displaying exogenous antigen bound to MHCII molecule.
193
what kind of cell does MHCII communicate with?
helper t-lymphocyte
194
What are the life events of lymphocytes?
formation of lymphocytes: primary lymphatic structures (red bone marrow and thymus). become able to recognize only one specific foreign antigen activation of lymphocytes: migrate to 2ndary lymphatic structures (lymph nodes, spleen, tonsils, MALT). have 1st exposure to antigen that they bind = activation ---\> replicate to form clones effector response: specific action of t & b lymphocytes to help eliminate antigen at infection site. t-lymphocytes migrate to site, b-lymphocytes (as differentiated plasma cells) remain in secondary lymphatic structure making & releasing large # of antibodies that enter blood & lymph & are transported to infection site
195
where do the life events of lymphocytes take place?
formation of lymphocytes - primary lymphatic structures activation of lymphocytes - secondary lymphatic structures effector response - site of infection
196
what does it mean if a lymphocyte is immunocompetent?
it is able to bind antigen and respond to it.
197
what do pre-t-lymphocytes possess?
unique TCR (T-cell receptor) receptor and both CD4 and CD8 proteins (double positive)
198
how are t-cell receptors produced?
randomly through gene shuffling
199
what is t-lymphocyte selection?
the T-lymphocytes have their TCR tested to determine whether it is able to bind to the MHC molecule with presented antigen and also to make sure it binds only to antigen that is foreign and nonself.
200
where does maturation of t-lymphocytes take place?
thymus
201
what selection processes occur in the thymus for t-lymphocytes?
positive and negative selection
202
what is positive selection of t-lymphocytes?
the t-lymphocyte must bind to a thymic epithelial cell that have MHC molecules or else it is eliminated thymic epithelial cells present MHC molecule to pre-T-lymphocyte, if it binds to MHC molecule, it survives, otherwise it is destroyed by apoptosis
203
what is negative selection of t-lymphocytes?
thymic dendritic cells present self-antigens with MHC class I and class II molecules. if it binds to the self-antigen, it is destroyed. cells learn to ignore molecules of the body - self-tolerance.
204
what percentage of t-lymphocytes survive thymic selection?
2%
205
what is the final step of t-lymphocyte selection?
each t-lymphocyte differentiates into either a helper t-lymphocyte ( CD4) or a cytotoxic t-lymphocyte (CD8) by losing the opposite protein.
206
what is a naive t-lymphocyte?
one that has not been exposed to the specific foreign antigen it recognizes
207
where do naive t-lymphocytes (helper and cytotoxic) go?
migrate from thymus to secondary lymphatic structures where they are housed.
208
where are b-lymphocytes selected?
in red bone marrow
209
where do naive b-lymphocytes go?
migrate from red bone marrow to secondary lymphatic structures where they are housed
210
what is clonal selection?
when a lymphocyte forms clones in response to a specific antigen
211
what activates a lymphocyte?
physical contact between a lymphocyte and the antigen it recognizes.
212
what is an antigen challenge?
the first encounter between an antigen and a lymphocyte
213
where does an antigen challenge typically occur?
in a secondary lymphatic structure usually depends on the point of entry of the antigen antigen in blood is taken to the spleen antigen that penetrates skin is engulfed & transported by epidermal dendritic cells to a lymph node antigen that enters through mucosal membrane of respiratory, GI or urogenital tracts comes into contact with tonsils or MALT
214
describe activation of helper t-lymphocytes
1) 1st stimulation: CD4 binds with MHCII molecule of APC (antigen-presenting cell); TCR (t-cell receptor) interacts with antigen within MHCII molecule (stabilized by CD4). disengages if it does not recognize antigen, if it does recognize, contact between 2 cells lasts several hours. 2) second stimulation: helper t-lymphocyte secretes IL-2 (occurs within about 24 hours). IL-2 acts as autocrine hormone further stimulating helper t-cell. proliferate and differentiates to form a clone of helper t-cell (activated and memory - activated continue to produce IL-2, memory cells wait for subsequent encounters with specific antigen)
215
describe activation of cytotoxic t-lymphocytes
1) first stimulation: CD8 binds with MHCI molecule of infected cell; TCR interacts with antigen w/in MHCI molecule 2) second stimulation IL-2 released from activated helper T-lymphocytes stimulates the cytotoxic t-lymphocyte (IL-2 is paracrine hormone here). upon activation, cytotoxic t-cell proliferates and differentiates into clones (activated and memory)
216
describe activation of b-lymphocytes
1)first stimulation: free antigen binds to BCR (b-cell receptor) and cross-links BCRs. stimulated b-cell engulfs & presents antigen to activated helper t-lymphocytes (like other APCs) 2) second stimulation: activated helper t-lymphocyte released IL-4 to stimulate b-lymphocyte. once activated, b-cell proliferates and differentiates (plasma cells that produce antibodies (most) and memory b-lymphocytes that are activated upon re exposure to same antigen)
217
what are the differences between memory b-lymphocytes and plasma cells?
memory b-lymphocytes retain their BCRs and have a longer life span (months to years). plasma cells live about 5-7days.
218
can a b-cell be stimulated without direct contact of a helper t-cell?
yes. but it cannot produce memory b-lymphocytes or antibodies without helper t-lymphocyte participation.
219
What is lymphocyte recirculation?
every several days, lymphocytes exit secondary lymphatic structures and circulate through blood and lymph - so odds for contact between antigen and lymphocyte increase. provides a means of delivering different lymphocytes to secondary lymphatic structures - making it more likely that a lymphocyte will encounter its antigen, if present.
220
what is the effector response?
specific mechanisms that activated lymphocytes use to help eliminate the antigen
221
what is the effector response of helper t-lymphocytes
activated & memory helper t-lymphocytes leave secondary lymphatic structure after several days of exposure to antigen & migrate to infection site ---\> there they release cytokines to regulate other immune cells
222
what is the effector response of cytotoxic t-lymphocytes?
activated & memory cytotoxic t-lymphocytes leave 2ndary lymphatic structures after several days & migrate to infection site in body tissue --\> destroy infected cells that display antigen. initiated when physical contact is made between cytotoxic t-cell & unhealthy or foreign cell. releases granules containing cytotoxic chemicals perforin & granzymes (induce apoptosis)
223
what is the effector response of b-lymphocytes?
antibodies are effectors of humoral immunity ---\> formed by plasma cells. plasma cells usually remain in lymph nodes. antibodies circulate through body in lymph & blood. plasma cells live about 5 days & produce hundreds of millions of antibodies against specific antigen.
224
what is an antibody titer?
circulating blood concentration of antibody against a specific antigen. measure of immune response
225
what is an antibody?
an immunoglobulin protein produced against a particular antigen
226
what do antibodies do?
tag specific antigens so that they can be eliminated
227
what is the structure of an antibody?
Y-shaped, soluble protein 4 polypeptide chains 2 identical heavy chains & 2 identical light chains variable region is at ends of the arms - contain antigen-binding site (most have 2 antigen-binding sites) constant region contains Fc region - portion of antibody that determines biological functions of antibody
228
What are the 5 major classes of immunoglobulins?
IgG IgM IgA IgD IgE (g-made)
229
what can antibody binding to antigen cause?
neutralization - antibody can physically cover antigenic determinant of pathogen to make it ineffective in causing harm or establishing infection agglutination - clumping precipitation - cross-link soluble antigens to form antigen-antibody complex - become insoluble & precipitate out of body fluids --\> engulfed & eliminated by phagocytic cells like macrophages
230
what happens to the Fc region of the antibody after the variable region binds to antigen?
it projects externally - can participate in complement fixation (IgG & IgM) can bind to specific complement proteins to cause activation of complement by classical pathway. can participate in opsonization (IgG) can cause opsonization - making it more likely to be seen by phagocytic cells - neutrophils & macrophages have receptors for Fc regions of certain antibodies & engulf antigen & antibody activation of NK cells (IgG) - can trigger activity of NK cells.
231
Describe the characteristics of IgG
75-85% of antibody in blood & predominant antibody of lymph, cerebrospinal fluid, serous fluid & peritoneal fluid. can neutralize (viruses, bacteria, toxins), agglutination, precipitation, complement activation, opsonization, NK cell activation, antibody-dependent cell-mediated cytotoxicity 23 day half life used for passive immunity: crosses placenta, component of breast milk.
232
describe the characteristics of IgM
found mostly in blood NOT efficient at virus neutralization most effective at causing agglutination of cells & binding complement. responsible for rejection of mismatched blood transfusions first produced antibody - only antibody produced in fetus, - component of breast milk 5 day half life
233
describe the characteristics of IgA
found in areas exposed to environment (external secretions - skin, mucus, saliva, tears, breast milk, colostrum) protects respiratory & GI tract. helps prevent pathogens from adhering to epithelial tissue & penetrating underlying tissue by neutralization great at agglutination 5.5 day half life
234
describe IgD
functions as antigen-specific B-lymphocyte receptor identifies when immature b-lymphocytes may be ready for activation half life 2.8 days identifies when immature b-cells may be ready for activation
235
describe IgE
low rate of synthesis usually formed in response to allergic reactions & to parasitic infections causes release of products from basophils mast cells. attracts eosinophils located in blood half life 2 days
236
How is adaptive immunity activated?
direct physical contact between a lymphocyte & an antigen
237
what happens with first exposure to an antigen?
limited numbers of helper t-lymphocytes, cytotoxic t-lymphocytes & B-lymphocytes recognize the antigen. lag time occurs between body's initial exposure to antigen & physical contact w/lymphocytes required to develop an immune response.
238
what does the antigen challenge cause?
formation of memory cells in response to activation of t-cells & b-cells. they are army of thousands against specific antigens --\> immunologic memory
239
what is the secondary response?
when vast numbers of memory cells make contact with antigen in subsequent exposures - more rapidly & more powerful response also called memory response or anamnestic response (not amnesiac) ---\> pathogen is usually eliminated before disease symptoms develop.
240
what is antibody titer?
concentration of antibody in blood serum degree of protection against an antibody is indicated by levels of circulating IgG
241
what is the lag or latent phase during primary response?
no detectable antibody in blood for 3-6 days. antigen detection, activation, proliferation, & differentiation of lymphocytes, development of memory lymphocytes - all happen during this phase
242
how long does it take for production of antibody to occur during primary response?
1-2 weeks, plasma cells produce IgM & then IgG. Titer levels peak & then decrease over time
243
what happens during lag or latent phase during secondary response?
much shorter lag phase due to presence of memory lymphocytes
244
how long does it take to produce antibodies during the secondary response?
levels rise more rapidly w/greater proportion of IgG antibodies. Higher level of IgG production may continue for longer periods - even years.
245
what is a vaccine?
attenuated (weakened) or dead microorganism or a component of a microorganism.
246
what is the function of a vaccine?
to stimulate immune system to develop memory b-lymphocytes so that secondary response will be stimulated upon contact with pathogen.
247
how is a vaccine different from having an active infection?
immune response to vaccine is primarily humoral-mediated branch (because weakened microbes in vaccine have a difficult time infecting cells to induce t-lymphocytes to establish cell-mediated immunity) booster shots may be needed depending on life span of memory b-lymphocytes.
248
what is active immunity?
results from direct encounter with a pathogen
249
how can active immunity be obtained?
naturally - individual is directly exposed to antigen artificially - exposure occurs through vaccine memory cells against that antigen are formed
250
what is passive immunity?
obtained from another individual
251
how can passive immunity be obtained?
naturally - transfer of antibodies from mother to fetus across placenta (IgG) or in breast milk (IgA, IgM, & IgG) artificially - serum containing antibodies against specific antigen is transferred from 1 individual to another individual has not had antigenic challenge & has not produced memory cells - so lasts only as long as antibody proteins are present.
252
what is hypersensitivity?
abnormal and exaggerated response of immune system to an antigen.
253
what are the different types of hypersensitivities?
acute (occur w/in seconds) - humoral immunity involve IgE subacute (occur w/in 1-3 hours) - humoral immunity involve IgG and IgM delayed (occur w/in 1-3 days) - cell-mediated immunity
254
what are allergies?
acute hypersensitivity - overreaction of immune system to noninfectious substance (allergen) like pollen, latex, peanuts, etc.
255
what are the 3 major phases associated with an allergic reaction?
1.sensitization phase: exposed to allergen, engulfed by APC & presented to helper t-lymphocyte. helper t-cells release cytokines that cause b-cells to mature into plasma cells that produce IgE antibodies against allergen. IgE antibodies bind to basophils & mast cells (by Fc region of antibody) 2. activation phase - reexposed to same allergen, allergen binds to IgE antibodies that are bound to basophiles & mast cells, cross-linking receptors 3. effector phase - mast cells or basophils release chemicals (histamine, heparin & eicosanoids) that cause inflammatory response
256
what can increased inflammatory response lead to in a hypersensitivity reaction?
hives, allergic asthma, anaphylactic shock (systemic vasodilation & inflammation - extensive loss of fluid from blood into interstitial space results in marked decrease in blood volume & blood pressure - may have insufficient blood pressure to maintain adequate perfusion), allergic rhinitis (contact w/mucous membranes of nasal passage & conjunctiva of eye --\> runny nose & watery eyes
257
what are the functions of the respiratory system?
air passageway site for exchange of O2& CO2 detection of odors sound production (vocal cords of larynx vibrate as air moves across them to produce sound - sounds resonate in upper respiratory structures)
258
what are the regions of the respiratory system?
upper respiratory tract - nose, nasal cavity & pharynx lower respiratory tract - larynx, trachea, bronchi, bronchioles, alveolar ducts, alveoli
259
what are the zones of the respiratory system?
conducting zone (passageways that serve primarily to transport or conduct air), passageways from the nose to the end of the terminal bronchioles respiratory zone (structures that participate in gas exchange with blood) respiratory bronchioles, alveolar ducts & alveoli
260
what is the structure of the mucous membrane that lines the respiratory tract?
epithelium resting upon a basement membrane, underlying lamina propia composed of areolar connective tissue. epithelium is ciliated in most portions of the conducting zone.
261
what is another name for the mucous membrane of the respiratory tract?
mucosa
262
what is the general pattern of structural change in the epithelium along the length of the respiratory tract?
becomes thinner form the nasal cavity to the alveoli. starts as pseudostratified ciliated columnar to simple ciliated columnar to simple cuboidal to simple squamous.
263
what are the exceptions to the epithelial structure in the respiratory tract?
1 - portions of the pharynx that serve as passageway for both air & food 2 - components of larynx that include vocal cords & area immediately superior to them both are lined by nonkeratinized stratified squamous epithelium to withstand abrasion.
264
what kinds of cells are in the epithelium of the respiratory tract?
goblet cells
265
what kinds of glands are in the lamina propia?
mucous and serous glands
266
how much mucus is produced daily by the respiratory tract, and what produces it?
1-7 Tablespoons produced by goblet cells in epithelia & mucous and serous glands in lamina propia
267
what is mucin?
protein in mucous that increases viscosity of mucous - better traps dust, dirt, microorganisms...
268
what do mucous secretions contain?
mucin substances to defend against microbes like lysozyme (antibacterial enzyme), defensins (antimicrobial proteins) & IgA
269
what is sputum?
mucus mixed with saliva & materials it entraps
270
describe the structure of the nose
bone, hyaline cartilage, dense irregular connective tissue covered with skin paired nasal bones form bridge 1 pair of lateral cartilages around bridge of nose 2 pairs of alar cartilages around tip nostrils are dense IR CT.
271
describe the nasal cavity
goes from nostrils to choanae (openings) that lead to pharynx floor formed by hard & soft palate roof formed by nasal, frontal, ethmoid & sphenoid bones & cartilage of nose nasal septum divides into right & left septum formed anteriorly by septal nasal cartilage & posteriorly by perpendicular plate of ethmoid superiorly & vomer bone inferiorly lateral walls of cavity have superior, middle & inferior nasal conchae
272
what are the turbinate bones?
the superior, middle & inferior nasal conchae
273
what do the conchae do?
partition nasal cavity into separate air passages called nasal meatus help produce turbulence in inhaled air
274
what are the parts of the nasal cavity?
nasal vestibule (internal to nostrils & lined by skin & coarse hairs called vibrissae - trap large particles) olfactory region - superior portion - way at the top respiratory region - the rest of the cavity
275
what are nasal hairs called?
vibrissae
276
what is the function of the olfactory region of the nasal cavity?
contains olfactory epithelium - pseudostratified ciliated columnar and olfactory receptors - molecules that dissolve in mucus covering olfactory epithelium stimulate olfactory receptors - detect different smells
277
what is the structure of the respiratory region of the nasal cavity?
lined by mucosa composed of pseudostratified ciliated columnar epithelium. lamina propia extensively vascularized paired nasolacrimal ducts drain lacrimal secretions from surface of each eye into this region
278
what are the functions of the nasal cavity?
warm (via extensive blood vessels in lining), cleanse (microbes & junk trapped in mucus overing inner lining, cilia sweep mucus to pharynx to be swallowed) & humidify air as it enters respiratory tract conchae enhance conditioning because they create turbulence - increases contact between inhaled air & mucous membranes
279
name the paranasal sinuses
frontal - top ethmoidal - middle maxillary - bottom sphenoidal - behind ethmoidal
280
what connects sinuses do the nasal cavity?
ducts
281
what lines the ducts & sinuses?
pseudostratified ciliated columnar epithelium - continuous with mucosa of nasal cavity mucus & trapped stuff swept from paranasal cavities into nasal cavity into pharynx & then swallowed
282
what is the pharynx?
throat - posterior to nasal cavity, oral cavity & larynx air is conducted along entire length, & food also is conducted along inferior portions
283
what are the regions of the pharynx?
nasopharynx, oropharynx, laryngopharynx
284
what composes the lateral walls of the pharynx?
skeletal muscles - for flexibility and distensibility for swallowed food
285
where is the nasopharynx?
posterior to nasal cavity & superior to soft palate
286
what prevents food from entering nasopharynx?
soft palate - elevates when we swallow
287
where are auditory tubes and what do they do?
lateral walls of nasopharynx connect nasopharynx to middle ear - equalize pressure between atmosphere & middle ear by letting excess pressure be released into nasopharynx
288
where and what are tubal tonsils?
collection of lymphatic nodules located near the pharyngeal openings of the auditory tubes
289
where are pharyngeal tonsils?
posterior nasopharynx wall (above the tubal tonsils) when enlarged, this tonsil is called adenoids.
290
where is the oropharynx?
immediately posterior to oral cavity extends from soft palate superiorly to hyoid bone inferiorly
291
where are the palatine tonsils?
lateral walls of oropharynx
292
where are lingual tonsils?
base of tongue - anterior region of oropharynx provide 1st line of defense against ingested or inhaled foreign materials
293
where is the laryngopharynx?
inferior, narrowed region of pharynx - directly posterior to larynx goes from hyoid bone & is continuous on its inferior end with larynx anteriorly and esophagus posteriorly
294
what is the larynx?
voice box - cylindrical airway - continuous superiorly with laryngopharynx & inferiorly with trachea
295
what is the function of the larynx?
passageway for air prevents ingested materials from entering respiratory tract produces sound for speech (ligaments w/in larynx vibrate as air passes over them) assists in increasing pressure in the abdominal cavity participates in sneeze & cough reflex (remove irritants from respiratory tract)
296
what is the valsalva maneuver?
epiglottis closes over larynx so air cannot escape while abdominal muscles contract ---\> increase abdominal pressure
297
what is the opening that connects the pharynx to the larynx?
laryngeal inlet
298
what is the laryngeal inlet?
the opening that connects the pharynx to the larynx
299
what is the anatomy of the larynx?
formed & supported by 9 pieces of cartilage that are held in place by ligaments & muscles 9 pieces of cartilage are: thyroid cartilage (biggest - shaped like a shield - forms lateral and anterior wall) cricoid cartilage - ring-shaped inferior to thyroid cartilage - attached to thyroid cartilage epiglottis - large leaf-shaped - anchored to inner aspect of thyroid 3 smaller paired cartilages: arytenoid, corniculate, cuneiform (located internally)
300
what is the laryngeal prominence?
v-shaped anterior projection of thyroid cartilage in larynx Adam's apple
301
what are the cartilages of the larynx composed of?
hyaline cartilage except epiglottis - it is composed of elastic cartilage
302
how are laryngeal ligaments classified?
extrinsic (attached to external surface of cartilages) intrinsic (located w/in larynx) - vocal ligaments & vestibular ligaments
303
describe vocal ligaments
composed of elastic connective tissue extend anterior to posterior between thyroid cartilage and arytenoid cartilages covered with mucous membrane to form vocal folds (true vocal cords - produce sound when air passes between them - avascular so white)
304
what is the glottis?
vocal folds + rima glottidis (opening between vocal folds)
305
what is the opening between the vocal folds called?
rima glottidis
306
describe the anatomy of the vestibular ligaments
extend between thyroid cartilage to arytenoid & corniculate cartilages - have mucosa covering them - form the vestibular folds superior to vocal folds false vocal cords - no function in sound production but protect vocal folds
307
what types of skeletal muscles compose part of the larynx wall?
extrinsic muscles (stabilize the larynx & help it move during swallowing) intrinsic (located within larynx - function in voice production & help close off larynx when swallowing)
308
how does sound originate?
intrinsic laryngeal muscles narrow opening of rima glottidis & air is forced past vocal cords during expiration - vocal cords vibrate
309
what determines characteristics of sound?
range (determined by length & thickness of vocal cords - longer & thicker = lower range) pitch (frequency of sound waves - amount of tension or tautness on vocal folds - the tenser, the higher pitch) loudness (force of air passing across vocal cords - more force = more sound)
310
how do spaces in pharynx, nasal & oral cavities, & paranasal sinuses participate in sound production?
they act as resonance chambers
311
what is the trachea?
windpipe extends inferiorly through neck into mediastinum from larynx to main bronchi. lies immediately anterior to esophagus & posterior to part of sternum about 5 inches long & 1 inch in diameter
312
describe the gross anatomy of the trachea
anterior & lateral walls supported by 15-20 c-shaped rings of hyaline cartilage (tracheal cartilages) - covered in perichondrium & dense fibrous membrane, open posteriorly & attached by trachealis muscle & elastic ligamentous membrane connected superiorly & inferiorly with each other by elastic connective tissue sheets --\> anular ligaments carina is a ridge of mucusal covered cartilage at the split of main bronchi
313
what forms the wall of the trachea?
from inside out: 1) mucosa (pseudostratified ciliated columnar epithelium w/goblet cells & lamina propia) cilia push stuff up toward larynx & pharynx so it can be swallowed or expelled. 2) submucosa (areolar CT houses larger blood vessels, nerve endings, serous & mucous glands & lymphatic tissue) 3) tracheal cartilage 4) adventitia (elastic connective tissue)
314
what is the bronchial tree?
branched system of air-conducting passage - originate in main bronchi & end in smallest bronchiole passageway
315
what does the trachea branch into?
right and left main bronchi (also called primary bronchi)
316
what is the difference between right & left main bronchi?
right is shorter & wider & more vertically oriented than left particles more likely to lodge in right main bronchus
317
what do main bronchi branch into?
lobar bronchi (secondary bronchi) --\> go into each lobe of lung (3 lobar bronchi on right, 2 lobar bronchi on left)
318
how many lobes does each lung have?
right - 3 left - 2
319
what do lobar bronchi branch into?
segmental bronchi (tertiary bronchi) right has 10 left has 8-10
320
how many different divisions of bronchial branch divisions are there?
9-12
321
what are the smallest branch of bronchi?
bronchioles - diameter less than 1mm
322
what is the last segment of the conducting pathway?
terminal bronchioles
323
what is the first segment of the respiratory zone?
respiratory bronchioles (terminal bronchioles lead to respiratory bronchioles)
324
what is bronchitis?
inflammation of bronchi caused by viral or bacterial infection
325
what is asthma?
chronic condition characterized by episodes of bronchoconstriction w/wheezing, coughing, shortness of breath, & excess pulmonary mucus. localized immune reaction results in swollen submucosa, increased production of mucus & bronchoconstriction
326
How can you distinguish between bronchi and bronchioles?
bronchi have incomplete rings or plates of hyaline cartilage to support walls bronchioles have no cartilage in walls, but have thicker layer of smooth muscle
327
what do the smallest respiratory bronchioles subdivide into?
thin airways called alveolar ducts that lead into alveolar sacs (grape-like bunches of alveoli at end of an alveolar duct)
328
where can you find alveoli and what are they?
respiratory bronchioles & alveolar ducts - alveoli are small saccular outpocketings
329
what are respiratory bronchioles, alveolar ducts & alveoli lined with?
respiratory bronchioles - simple cuboidal epithelium alveolar ducts & alveoli - simple squamous epithelium thinner than in conducting system to facilitate gas diffusion between alveolus and pulmonary capillaries
330
what are alveolar pores?
openings in walls of adjacent alveoli - allow collateral ventilation
331
what types of cells form alveolar walls?
alveolar type I cell (squamous alveolar cell) - 95% of surface - form thin barrier between air in alveoli & blood in pulmonary capillaries - internal surface is moist alveolar type II cell (septal cells) - secrete oily fluid - pulmonary surfactant - help prevent collapse of alveoli
332
what is the 3rd type of cell that forms part of the alveolus?
alveolar macrophage (dust cell) - leukocyte that is either fixed or free - both engulf foreign bodies & leave lungs either through lymph vessels or by being coughed up in sputum & expectorated from the mouth.
333
what is the respiratory membrane?
thin barrier that O2 and CO2 diffuse across during gas exchange between alveoli & blood in pulmonary capillaries.
334
what composes the respiratory membrane?
alveolar epithelium, its basement membrane that is fused to capillary basement membrane, and capillary endothelium
335
where is the base of the lungs?
rests inferiorly upon the diaphragm
336
where is the apex of the lungs?
(cupula) slightly superior & posterior to the clavicle
337
where are the lung surfaces?
costal surface (adjacent to ribs) mediastinal surface (adjacent to mediastinum) diaphragmatic surface (adjacent to diaphragm)
338
what is the hilum?
indented region on mediastinal surface of each lung through which pass the bronchi, pulmonary vessels, lymph vessels & pulmonary plexus autonomic nerves
339
what is the root of the lung?
structures that extend from the hilum bronchi, pulmonary vessels, lymph vessels, & pulmonary plexus autonomic nerves
340
name the fissures and lobes of the right lung
horizontal fissure separates superior lobe from middle lobe. oblique fissure separates middle lobe from inferior lobe.
341
name the structures of the left lung
oblique fissure separates superior lobe from inferior lobe lingula is a projection from the superior lobe 2 surface indentations accommodate the heart: cardiac impression on medial surface & cardiac notch on anterior surface groovelike impression on medial surface accomodates descending thoracic aorta
342
how are the left & right lungs partitioned?
into bronchopulmonary segments 10 in right lung, 8-10 in left each encapsulated within connective tissue & supplied by its own segmental bronchus, a branch of both the pulmonary artery and vein, & lymph vessels.
343
how is each lung segment partitioned?
into lobules - each is surrounded by connective tissue & supplied by terminal bronchiole, arteriole, venule, and lymph vessel.
344
what are the types of blood circulation associated with lungs?
pulmonary circulation and bronchial circulation pulmonary conducts blood to & from gas exchange surfaces of lungs to replenish O2 and get rid of CO2 bronchial circulation - part of systemic circulation - transports oxygenated blood to lung tissues
345
how is lymph drained from lungs?
lymph vessels & nodes are located w/in connective tissue of lung, around the bronchi & in pleura remove excess fluid from lungs in lymph vessels, then filtered through lymph nodes (which may darken over time)
346
what kind of innervation does the larynx, trachea and bronchial tree and lungs have?
smooth muscles are innervated by autonomic nervous system bronchioles have both sympathetic (originates from T1-T5 segments of spinal cord - causes bronchodilation) and parasympathetic innervation (from vagus nerves CNX - stimulates bronchoconstriction) vagus nerve also innervates larynx (damage can cause monotone or hoarse voice)
347
what is pleura?
serous membrane that lines the outer lung surfaces & adjacent internal thoracic wall composed of simple squamous epithelium
348
what are the layers of the pleura?
visceral pleura tightly adheres to lung surface parietal pleura lines internal thoracic walls, lateral surfaces of mediastinum, & superior surface of diaphragm layers are continuous at hilum of each lung
349
where is the pleural cavity found?
between the visceral and parietal serous membrane layers
350
when is the pleural cavity considered a potential space?
when lungs are fully inflated, because the visceral & parietal pleurae are almost in contact with each other
351
what lubricates pleural surfaces?
serous fluid that is produced by serous membrane (oily) contains less than 15mL drained by lymph vessels
352
what keeps lungs inflated?
chest wall expands outwardly & lungs cling to internal surface (due to surface tension caused by serous fluid w/in pleural cavity) elastic connective tissue in lungs makes lungs pull inward outward pull of chest wall & inward pull of lungs creates vacuum w/in pleural cavity so pressure is generated (intrapleural pressure) lower than pressure inside lungs (intrapulmonary pressure) --\>difference in pressure keeps lungs inflated
353
what is respiration?
exchange of respiratory gases between atmosphere and tissue cells of the body
354
what are the 4 processes of respiration?
pulmonary ventilation (movement of respiratory gases b/t atmopshere & alveoli of lungs alveolar gas exchange (external respiration) - exchange of gas b/t alveoli & blood gas transport - transport of gas w/in blood b/t lungs & systemic cells of body systemic gas exchange - exchange gas b/t blood & systemic cells of body
355
describe movement of respiratory gases
1. air (w/O2) inhaled into alveoli during inspiratory phase of pulmonary ventilation 2. O2 diffuses from alveoli into pulmonary capillaries during alveolar gas xchange 3. gas transport of O2 w/in blood from lungs to systemic cells of body 4. O2 diffuses from blood into systemic cells through capillaries 5. CO2 diffuses into capillaries from systemic cells 6. CO2 transported by blood from systemic cells to lungs 7. CO2 diffuses from blood into alveoli 8. CO2 in air exhaled from alveoli during expiratory phase of pulmonary ventilation
356
what is pulmonary ventilation?
breathing
357
what are the phases of pulmonary ventilation?
inspiration (inhalation) expiration (exhalation)
358
what are the 2 types of breathing?
quiet - rhythmic breathing that occurs at rest forced - vigorous breathing w/exercise or exertion.
359
what are the steps of pulmonary ventilation?
1. autonomic nuclei in brain stimulate skeletal muscles to cyclically contract & relax --\> thoracic cavity volume changes 2. thoracic cavity changes result in changing pressure --\> changing pressure gradient between lungs & atmosphere 3. air moves down pressure gradient to enter lungs during inspiration or exit lungs during expiration.
360
what are the categories of skeletal muscles of breathing?
muscles of quiet breathing muscles of forced inspiration muscles of forced expiration
361
what are the muscles of quiet breathing?
diaphragm (dome shaped when relaxed, flattened in contracted) external intercostals (elevate ribs & increase transverse dimensions of thoracic cavity)
362
what are the muscles of forced inspiration?
sternocleidomastoid (lifts rib cage) scalenes (elevates ribs 1 & 2) pectoralis minor (elevates ribs 3&4) serratus posterior superior (lifts ribs 2-5) erector spinae (extends vertebral column)
363
what are the muscles of forced expiration?
internal intercostals (depress ribs & decrease transverse dimensions of thoracic cavity) abdominal muscles (compress abdominal contents, forcing diaphragm into higher domed position) transversus thoracis (depresses ribs 2-6) serratus posterior inferior (depresses ribs 9-12).
364
what do you call the muscles of forced inspiration and forced expiration?
accessory muscles of breathing
365
in what dimensions does the thoracic cavity volume change during breathing?
vertically (diaphragm), laterally (elevated or depressed rib cage) & anterior-posteriorly (inferior part of sternum moves out & in)
366
What is Boyle's Gas Law?
P1V1=P2V2 pressure is inversely related to volume
367
what is atmospheric pressure at sea level?
760 mmHg
368
what is alveolar volume?
collective volume of alveoli within the lungs
369
when is intrapulmonary pressure equal to atmospheric pressure?
at the end of both inspiration and expiration
370
what is intrapleural pressure?
pressure exerted within the pleural cavity (what separates lungs from the wall of the thoracic cavity)
371
how does intrapleural pressure relate to intrapulmonary pressure?
intrapleural pressure is always lower than intrapulmonary pressure ---\> lungs remain inflated
372
how much air moves from atmosphere into lungs during quiet breathing?
about .5 L
373
how much of the thoracic volume change does the diaphragm account for during quiet breathing?
about 2/3
374
summarize changes associated with quiet breathing
inspiration: diaphragm & external intercostals contract, pleural cavity & lung volume increases, pressure decreases, air moves into lungs expiration: diaphragm & external intercostals relax, pleural cavity & lung volume decrease, pressure increases, air moves out of lungs
375
what coordinates skeletal muscles of breathing?
nuclei within brainstem housed int he medullary respiratory center w/in medulla oblongata (below pons) and the pontine respiratory center w/in the pons(neck/belly of seahorse) both together called the respiratory center
376
what are the groups of nuclei in the medulla oblongata?
ventral respiratory group (VRG) - contain inspiratory & expiratory neurons dorsal respiratory group (DRG) relays its input to the VRG
377
what does the ventral respiratory group do during quiet breathing?
initiates neural impulses for inspiration & expiration. axons from upper motor neurons extend from VRG to spinal cord. Axons from lower motor neurons extend from spinal cord & form the phrenic nerves that innervate the diaphragm & the intercostal nerves that innervate the intercostal muscles action potentials initiated by inspiratory neurons in VRG, sent through nerve pathways for about 2 seconds. AP are also sent from VRG inspiratory neurons to VRG expiratory neurons. inspiratory neuron stimulation causes diaphragm & external intercostal muscles to contract. then those neurons are inhibited by expiratory neurons of VRG and pontine respiratory group. inspiratory impulses stop for about 3 seconds
378
what happens to action potential during quiet breathing inspiration?
the intensity increases over the 2 seconds
379
what causes inspiratory neuron impulses to cease?
they are inhibited by expiratory neurons of the VRG and the pontine respiratory group. they cease for about 3 seconds, causing diaphragm & external intercostal muscles to relax & thoracic cavity volume to decrease
380
what does the pons respiratory center do?
provides a smooth transition between inspiration and expiration by sending impulses to the VRG
381
what is a typical quiet breathing rhythm?
2 seconds of inspiration followed by 3 seconds of expiration ---\> respiratory rate of 12Xper minute 12-15/minute is average quiet breathing rate
382
what is eupnea?
12-15 respiratory times per minute during quiet breathing
383
how is breathing rate & depth altered?
sensory impulses are sent to DRG (dorsal respiratory group in medulla oblongata) from chemoreceptors, proprioreceptors, stretch receptors & irritant receptors & input from higher brain centers activated DRG relays AP to VRG resulting in change in rhythm & force of breathing rate of breathing change results by altering amount of time spent in inspiration & expiration depth of breathing happens through stimulation of accessory muscles (greater thoracic volume changes)
384
what is apnea?
absence of breathing
385
describe reflexes involving chemoreceptors
central & peripheral chemoreceptors monitor H+ & gas concentration in blood & cerebrospinal fluid (CSF) (partial pressure of CO2 & O2)
386
where are central chemoreceptors located?
on the ventrolateral surface of the medulla - close to medullary respiratory center
387
what do central chemoreceptors do?
monitor pH changes in CSF induced by changes in blood CO2 pressure if there is a high concentration of CO2, respiration rate & depth are increased & extra CO2 is expelled. if there is too little CO2, pH increases & breathing rate & depth decrease
388
where are peripheral chemoreceptors located?
walls of specific blood vessels - carotid bodies at split of common carotid artery into external and internal carotid arteries & aortic bodies housed in aortic arch
389
what do peripheral chemoreceptors do?
detect changes in arterial blood stimulated by changes in blood gases or pH, carotid bodies send sensory impulses through glossopharyngeal nerves & aortic bodies send sensory impulses through vagus nerves to respiratory center alters action potential to breathing muscles ---\> increase or decrease in rate or depth
390
how does pH change?
blood CO2 concentration
391
how do peripheral chemoreceptors differ from central chemoreceptors?
peripheral chemoreceptors also are stimulated by changes in H+ concentration (not just pH--\>CO2) happens as a result of kidney failure or diabetes mellitus ---\> results in increase in breathing rate & depth
392
how does O2 level relate to CO2 level in stimulating peripheral chemoreceptors?
O2 arterial levels must decrease substantially before they can stimulate chemoreceptors independently of CO2 levels CO2 levels are most important stimulus affecting breathing rate & depth
393
where are proprioceptors & how do they affect breathing?
within joints & muscles - stimulated by body movement which increases breathing depth
394
where are baroreceptors?
stretch receptors within visceral pleura and bronchiole smooth muscle - initiate reflex to prevent over stretching of lungs by inhibiting inspiration activities --\> inhlation reflex (Hering-Breuer reflex). Protects lungs from over stretching when overstretched, send sensory impulses through vagus nerves to respiratory center to shut off inspiration activity ---\> expiration
395
how does the hypothalamus influence breathing rate?
increases breathing rate if body is warm, decreases if body is cold.
396
how are respiratory structures controlled?
innervated by axons of lower motor neurons of autonomic nervous system & controlled by brainstem nuclei
397
how are breathing muscles controlled?
innervated by axons of lower motor neurons of somatic nervous system. control of breathing muscles comes from nuclei in brainstem & cerebral cortex
398
how is breathing controlled both reflexively & consciously?
nuclei of respiratory center regulate normal breathing w/rhythmic output long lower motor neurons of phrenic & intercostal nerves - alters breathing rate & depth in response to various sensory input. cerebral cortex consciously regulates breathing by directly stimulating lower motor neurons that extend to skeletal muscles of breathing
399
what is monitored by the 2 different types of chemoreceptors?
central chemoreceptors monitor CSF: H+ in CSF (produced from blood CO2) peripheral chemoreceptors monitor blood: 1)H+ in blood (produced from blood CO2) 2) H+ from metabolic acid, such as occurs in ketoacidosis; and 3) PO2 in blood.
400
what is airflow?
the amount of air that moves into and out of the lungs with each breath
401
what influences airflow?
pressure gradient between atm and intrapulmonary pressure and resistance that occurs due to conditions w/in airways, lungs & chest wall F=(Patm - Palv)/R F=flow R=resistance flow directly related to pressure gradient & inversely related to resistance
402
how may resistance be altered?
1)decrease in elasticity of chest wall & lungs --\> increase resistance 2) change in bronchiole diameter or size of passageway through which air moves --\> broncho constriction = more resistance 3) collapse of alveoli ---\> increased resistance
403
what causes decrease in chest elasticity?
age vertebral column malformation (like scoliosis) arthritis within thoracic cage elastic CT in lungs replaced by scar tissue (inflexible) ---\> happens with pulmonary fibrosis
404
what causes bronchioconstriction?
parasympathetic stimulation histamine release exposure to cold decreasing lumen size through accumulation of mucus or inflammation in bronchioles
405
what causes bronchodilation?
sympathetic stimulation release of epinephrine from adrenal medulla or external administration of epinephrine
406
how does prematurity affect resistance?
premature infants unable to produce enough pulmonary surfactant (starts 2 months prior to birth in healthy infants), so alveoli collapse with each expiration. alveoli are sticky (wet inner surface), so need more force in inspiration to overcome surface tension --\> acute respiratory distress syndrome (ARDS)
407
what is compliance?
ease with which the lungs and chest wall expand the easier the lung expansion, the greater the compliance
408
how much total body energy is normally spent in quiet breathing?
5%
409
what is pulmonary ventilation?
amount of air that is moved between atmosphere and alveoli in 1 minute tidal volume X respiration rate = pulmonary ventilation usually 500mL X 12 breaths/min = 6 L/min
410
what is tidal volume?
amount of air taken per breath - usually about 500mL in an adult
411
is all of the air taken in during pulmonary ventilation available for gas exchange?
no - only the air that reaches the alveoli
412
what is the anatomic dead space?
collective space in the conducting zone where no gas exchange takes place
413
what is the average volume of anatomic dead space?
150 mL
414
what is alveolar ventilation?
amount of air that reaches alveoli & is available for gas exchange per minute (tidal volume - anatomic dead space) X respiration rate = alveolar ventilation (500mL - 150mL) X 12 = 4.2 L/min
415
what is physiologic dead space?
normal anatomic dead space plus any loss of alveoli (can be due to damage to alveoli or change in respiratory membrane - like when fluid accumulates in lungs w/pneumonia)
416
what measures volume of air that enters & leaves the lungs?
spirometer
417
what are the major respiratory volumes that are usually measured?
tidal volume - amount of air inhaled or exhaled per breath during quiet breathing inspiratory reserve volume - amount of air that can be forcibly inhaled beyond tidal volume (measure of lung compliance) expiratory reserve volume - amount that can be forcibly exhaled beyond the tidal volume (measure of lung elasticity) residual volume - amount of air left in lungs even after most forceful expiration
418
what respiratory capacities can be calculated from respiratory volumes?
inspiratory capacity = tidal volume + inspiratory reserve volume functional residual capacity = expiratory reserve volume + residual volume (air that is normally left in lungs after quiet respiration) vital capacity = tidal volume + inspiratory and expiratory reserve volumes (measure of total amount of air that a person can exchange through forced breathing) total lung capacity = tidal volume + inspiratory reserve volume + expiratory reserve volume + residual volume (maximum volume of air that lungs can hold)
419
what is forced expiratory volume?
percentage of vital capacity that can be expelled in a specific period of time healthy person should be able to expel 75-85% of vital capacity in 1 second
420
what is maximum voluntary ventilation?
greatest amount of air that can be taken into & then expelled from the lungs in 1 minute
421
what is the hilum?
the involuted portion of the lymph node where an efferent lymphatic vessel exits
422
describe the capsule of a lymph node
composed of CT tissue, encapsulates node & sends internal extensions into node called trabeculae subdivide node into compartments CT provides pathway where blood vessels and nerves may enter lymph node
423
what are the regions of a lymph node?
outer cortex inner medulla
424
what composes a lymph node cortex?
multiple lymphatic nodules which are composed of reticular fibers that support inner germinal center - where B-lymphocytes proliferate & some macrophages germinal center is surrounded by mantle zone that contains t-lymphocytes, macrophages, dendritic cells
425
what composes a lymph node medulla?
has strands of b-lymphocytes, t-lymphocytes & macrophages supported by CT fibers called cords
426
where are lymphatic sinuses located?
in the cortex (cortical sinus) and medulla (medullary sinus) of lymph nodes they are tiny open channels - lined with macrophages
427
what is the difference between Hodgkin lymphoma and non-hodgkin lymphoma?
Hodgkin has Reed-Sternberg cells (treatable if caught early - take out tumor, radiation, chemotherapy) Non-Hodgkin more common - develop from abnormal b-cells (sometimes t-cells) - some are treatable, some not so much.
428
describe lymph flow through lymph nodes
lymph enters through afferent lymphatic vessels, goes through lymph node sinuses, monitored for presence of foreign or pathogenic material. macrophages remove foreign debris from lymph. exits through efferent lymphatic vessel goes from one node to another (in clusters) - extra filtering lymphocytes residing in lymph node can initiate immune response after contacting foreign substance (cell division in germinal centers) - some remain in node, others transported in lymph, enter blood & go to areas of infection
429
what causes swollen glands?
person with infection --\> swollen tender lymph nodes --\> sign that lymphocytes are proliferating to fight infection.
430
what is the largest lymphatic organ in the body?
spleen
431
where is the spleen located?
upper left quadrant of abdomen, inferior to diaphragm & adjacent to ribs 9-11. lateral to left kidney & posterolateral to stomach
432
describe the spleen hilum
on concave anteromedial border - where blood vessels & nerves enter & exit spleen splenic artery delivers blood, splenic vein drains blood
433
Describe the histology of the spleen
surrounded by CT capsule from which trabeculae extend & subdivide it into red & white pulp white pulp consists of spherical clusters of t-lymphocytes, b-lymphocytes & macrophages - also has a central artery red pulp is remaining tissue - contains erythrocytes, platelets, macrophages & b-lymphocytes. cells here housed in reticular CT & form splenic cords. also has splenic sinusoids (permeable capillaries so blood can easily enter & exit)
434
what does the spleen store?
reservoir for platelets - stored in red pulp houses about 30% of all platelets reenter blood when necessary
435
what does the spleen filter?
blood (not lymph)
436
describe blood flow through spleen
enters through central arteries where white pulp lymphatic cells monitor blood for foreign materials. then travels through sinusoids of red pulp. macrophages line sinusoids & eat foreign stuff plus old erythrocytes & platelets. splenic artery--\> central artery (white pulp) ---\> splenic sinusoid (red pulp) --\> venules ---\> splenic vein
437
what are the functions of the spleen?
1) phagocytosis of bacteria & foreign materials in blood (red & white pulp) 2) phagocytosis of old, defective erythrocytes & platelets from blood (red pulp) 3) reservoir for platelets (red pulp)
438
what secondary lymphatic structure is not completely surrounded by CT capsule?
tonsils
439
where are the tonsils located?
pharyngeal tonsil - posterior wall of nasopharynx (highest one) palatine tonsils - posterolateral region of oral cavity (middle one) lingual tonsils - posterior 1/3 of tongue (lowest)
440
which tonsils are called adenoids & why?
pharyngeal tonsils - when they are swollen they are called adenoids
441
what are lymphatic nodules?
small, oval clusters of lymphatic cells w/some extracellular matrix not completely surrounded by CT capsule
442
what is diffuse lymphatic tissue?
scattered lymphatic nodules
443
what is MALT?
mucosa-associated lymphatic tissue located in the lamina propia of mucosa of GI, respiratory, genital & urinary tracts help defend against foreign substances that come in contact with mucosal membranes
444
what are peyer patches?
collections of lymphatic nodules in the mucosa of the small intestine (in the ileum).
445
how does gas move during gas exchange?
independently down it's own partial pressure gradient. between air (in the alveoli) and liquid (blood)
446
what is Dalton's law?
total pressure in a mixture of gases = sum of all individual partial pressures
447
which partial pressures are relevant in the body?
partial pressures of O2 and CO2 within alveoli in lungs, systemic cells & circulating blood
448
why are partial pressures of gases within alveoli different from atmospheric partial pressures?
1) air from environment mixes with air from anatomic dead space in respiratory tract 2) O2 diffuses out of alveoli into blood & CO2 diffuses into alveoli from blood 3) H2O higher in alveoli because of humidifying effects PO2 lower in alveoli than atmospher, PCO2 higher in alveoli than atmosphere
449
how does partial pressure in systemic cells compare to in alveoli?
in systemic cells, PO2 lower & PCO2 higher than in alveoli
450
where is partial pressure relatively constant, and where is it changing?
in blood it is changing, in systemic cells & alveoli, it is relatively constant
451
what is henry's law?
at given temp, solubility of a gas in a liquid depends on partial pressure of gas in air, and solubility coefficient of gas in the liquid gases with lower solubility require more pressure to dissolve into liquid
452
how soluble are O2 and CO2 in water?
O2 low, CO2 24 times more soluble than O2 nitrogen even less soluble than O2
453
what is ventilation-perfusion coupling?
ability of bronchioles to regulate airflow and arterioles to regulate blood flow simultaneously ventilation is altered by changes in bronchodilation & bronchoconstriction (dilate in response to increase in PCO2 & constrict in response to decrease in PCO2) perfusion is altered by pulmonary arteriole dilation & constriction - dilate in response to increase in PO2 or decrease in PCO2, or constrict in response to decrease in PO2 or increase in PCO2
454
what is this?
jkl10 wow this is cool f
