Lesson 11 Flashcards
1
Q
immune system is not an organ system but
A
a cell population that inhabits all organs
2
Q
what is the function of the immune system
A
defends the body from agents of disease
3
Q
the lymphoid system
A
immune cells concentrated in true organs system
4
Q
what is the lymphoid system
A
network of organs and vein-like vessels that recover fluid
5
Q
what are the functions of the lymphoid system? (3)
A
- inspect it for disease agents
- activate immune responses
- return fluid to the bloodstream
6
Q
lymphatic system
A
lymphatic vessels that penetrate nearly every tissue and a collection of lymphoid tissues and organs that produce immune cells
7
Q
fluid recovery in the lymphatic system
A
fluid continually filters from the blood capillaries into the tissue spaces
8
Q
blood capillaries reabsorb ____ of fluid
A
85%
9
Q
where does the rest of the fluid recovered go? how much is it?
A
- lymphatic vessels
- 15%
10
Q
lymphedema
A
swelling due to interference in lymphatic drainage
11
Q
immune surveillance in the lymphatic system
A
excess filtered fluid picks up foreign cells and chemical from the tissues pass through lymph nodes
12
Q
what happens in the lymph nodes
A
immune cells stand guard against foreign matter
13
Q
what happens when foreign materials pass through lymph nodes?
A
activates a protective immune response
14
Q
lipid absorption in the lymphatic system
A
lacteals in small intestine absorb dietary lipids that are not absorbed by the blood capillaries
15
Q
components of the lymphoid system?
A
- lymph
- lymphatic vessels
- lymphoid tissue
- lymphoid organs
16
Q
lymphatic vessels
A
transport lymph
17
Q
lymphoid tissues
A
aggregates of lymphocytes and macrophages that populate many organs of the body
18
Q
lymphoid organs
A
- organs where lymphoid cells are concentrated
- surrounded by connective tissue capsules
19
Q
lymph
A
- clear colorless fluid similar to plasma but low in protein
- recovered fluid
20
Q
lymph originates as ___ and is then taken up by lymphatic vessels
A
tissue fluid
21
Q
does chemical composition vary in different places in the body?
A
yes
22
Q
lymph collected from the intestine
A
look milky
23
Q
why does intestinal lymph look milky
A
high lipid content
24
Q
when is lymph collected
A
after lymph nodes have high amounts of lymphocytes
25
lymphatic capillaries
microscopic vessels that penetrate nearly every tissue of the body
26
lymphatic vessels are absent in
cartilage, cornea, bone, and bone marrow
27
lymphatic capillary wall
endothelial cells overlapping each other like roof shingles
28
lymphatic capillaries are ___ at one end
closed
29
anchoring filaments
anchor the cells of lymphatic vessels to surrounding tissue
30
intercellular clefts
gaps between cells that are large enough to allow bacteria and cells to enter lymphatic capillary
31
endothelial cells in lymphatic capillaries create what?
valve-like flaps that open and close with interstitial fluid pressure
32
when are the flaps in lymphatic capillaries open?
when interstitial fluid pressure is high
33
when are flaps in lymphatic capillaries closed?
when interstitial fluid pressure is low
34
as tissues swell with fluid it causes what to occur?
the overlapping edges of the endothelial cells to pry apart and drain the fluid into the lymphatic capillary
35
what are the three layers of larger lymphatic vessels?
- tunica interna
- tunica media
- tunica externa
36
lymphatic capillaries merge to form
collecting vessels
37
collecting vessels converge to form
lymphatic trunks
38
lymphatic trunks do what?
drain a major portion of the body of lymph
39
what are the two collecting ducts
- right lymphatic duct
- thoracic duct
40
right lymphatic duct receives lymph from
- right arm
- right side of head and thorax
41
where does the right thoracic duct empty into
right subclavian vein
42
thoracic duct receives lymph from
- below diaphragm
- left arm
- left side of head, neck, and thorax
43
which lymphatic duct is longer and larger?
thoracic duct
44
thoracic duct begins as
sac in abdomen
45
what is the sac that starts the thoracic duct called?
cisterna chyli
46
where does the thoracic duct empty
left subclavian vein
47
path from the tissue fluid back to bloodstream (8)
- lymphatic capillaries
- collecting vessels
- 11 lymphatic trunks
- two collecting ducts
- subclavian veins
- brachiocephalic veins
- superior vena cava
- right atrium
48
characteristics of lymph flow compared to venous return
- forces similar to venous return but no pump
- flows at low pressure and slower speed than venous blood
49
what stims the contraction of lymph vessels
stretching of vessels
50
what moves lymph along in lymph vessels (5)
- rhythmic contractions of lymph vessels
- squeezing of skeletal muscles
- rhythmic pulsations of nearby arteries
- thoracic pump
- rapidly flowing blood in subclavian vein drawing lymph to it
51
cells associated with the lymphoid system
- neutrophils
- natural killer cells
- T cells
- B cells
- macrophages
- dendritic cells
52
neutrophils
antibacterial
53
natural killer cells
- NK
- lymphocytes that attack and destroy infected host cells and cancerous cells
54
T cells
- T lymphocytes
- mature in thymus
55
B cells
- B lymphocytes
- activation causes proliferation and differentiation into plasma cells and produce antibodies
56
macrophages aka
antigen-presenting cells
57
macrophages
- large phagocytic cells
- display antigens on surface to alert other immune cells
58
dendritic cells
antigen-presenting cells found in skin, mucous membranes, and lymphoid organs
59
lymphoid tissue
aggregations of lymphocytes in the connective tissues of mucous membranes and various organs
60
diffuse lymphoid tissue
- lymphocytes are scattered
- not densely clustered
61
where is diffuse lymphoid tissue most prevalent
body passages open to the exterior (respiratory, digestive, urinary, and reproductive)
62
when in mucous membranes diffuse lymphoid tissues are called
mucosa-associated lymphoid tissue (MALT)
63
lymphoid nodules (follicles)
- lymphocytes and macrophages gather in dense masses
- may be temporary or permanent
64
aggregated lymphoid nodules
- Peyer patches
- large clusters of nodules in small intestine
65
lymphatic organs have connective tissue capsule that does what?
separates lymphatic tissue from neighboring tissues
66
primary lymphoid organs include
red bone marrow and thymus
67
why are red bone marrow and thymus primary lymphoid organs
sits where T and B cells are immunocompetent
68
immunocompetent
able to recognize and respond to antigens
69
secondary lymphoid organs include
tonsils, lymph nodes, and spleen
70
why are lymph nodes, spleen, and tonsils secondary lymphoid organs
locations where immunocompetent cells migrate and populate
71
red bone marrow
soft, loosely organized, highly vascular material separated from osseous tissue by endosteum of bone
72
red bone marrow involved in
hematopoiesis and immunity
73
what happens in blood-forming cells
secrete colony stim factors that stim stem cells to produce the formed elements
74
blood forming cells attached to ____ and _____
- reticular cells
- other elements of marrow stroma
75
as blood cells mature what do they do?
push their way through the reticular and endothelial cells to enter sinus and flow away in bloodstream
76
thymus
bilobed organ located in the superior mediastinum between sternum and aortic arch
77
thymus is apart of which organ systems?
- endocrine
- lymphoid
- immune
78
the thymus houses ____ and secretes ____
- developing T cells
- hormones regulating the activity of T cells
79
with age the thymus exhibits large degree of
involution
80
involution
degeneration or shrinkage
81
by age 65 what happens to the thymus
unable to make new T cells
82
what is it called when thymus can't make T cells anymore
immunosenescence
83
immunosenescence does what to older people
leaves older people vulnerable to infections and cancer
84
fibrous capsule gives off ___ that divides gland into nodes
trabeculae
85
lobes of the thymus have ___ and ___ populated by T cells
cortex and medulla
86
thymic epithelial cells are involved in
T cell development
87
what do thymic epithelial cells secrete? (5)
signaling molecules thymosin, thymopoietin, thymulin, interleukins, and interferons
88
cortical epithelial cells
along with pericytes surround capillaries to form blood thymus barrier
89
lymph nodes
bean-shaped structures that cleanse lymph and are sites of lymphocyte activation
90
what is the most numerous lymph organ?
lymph nodes
91
how many lymph nodes are in a typical young adult?
450
92
lymph nodes are enclosed with
fibrous capsule with trabeculae that divide interior into compartments
93
parenchyma of lymph node divided into ___ and ___
cortex and medulla
94
germinal centers in cortex
where B cells multiply and differentiate into plasma cells
95
several afferent vessels lead into node along
convex surface
96
lymph leaves node though ___
efferent lymphatic vessels
97
how many efferent lymph vessels are there usually
1-3
98
where do efferent lymph vessels leave from
hilum
99
what are all locations where lymph nodes are concentrated? (7)
- cervical
- axillary
- thoracic
- abdominal
- intestinal and mesenteric
- inguinal
- popliteal
100
where are the thoracic lymph nodes mostly located in the thoracic cavity?
mediastinum
101
where are abdominal lymph nodes located?
posterior abdominopelvic wall
102
where are intestinal and mesenteric lymph nodes located
mesenteries and near appendix and intestines
103
lymphadenitis
swollen, painful lymph node responding to foreign antigen
104
lymphadenopathy
collective term for all lymph node diseases
105
metastasis
cancerous cells break free from original primary tumor travel to other sites in the body and establish new tumors
106
metastasizing cells ____ enter lymphatic cells
easily
107
what tends to happen when cancer metastisizes in lymph node?
lodge in the first one they encounter, multiply there, and eventually destroy node
108
cancerous nodes are
swollen, firm, and painless
109
treatments of breast cancer
lumpectomy, mastectomy, removal of nearby axillary nodes
110
tonsils
patches of lymphoid tissue located at entrance to the pharynx
111
what do tonsils do?
guard against ingested or inhaled pathogens
112
tonsils are covered with ___ and have ____
- epithelium
- deep pits
113
tonsillar crypts
deep pits in tonsils covered by lymphoid nodules
114
tonsils have ___ fibrous capsule
incomplete
115
tonsilitis
acute inflammation of palatine tonsils
116
what is the largest lymph organ
spleen
117
location of the spleen
inferior to diaphragm and posterolateral to stomach
118
what two tissue types does parenchyma of liver exhibit
- red pulp
- white pulp
119
red pulp
sinuses filled with erythrocytes
120
white pulp
lymphocytes, macrophages surrounding small branches of splenic artery
121
what is the function of the spleen?
- erythrocyte graveyard
- blood cell production in fetus
- maintains army of monocytes for release when needed
- stabilize blood volume through plasma transfer to lymph system
122
spleen is
highly vascular and vulnerable to trauma and infection
123
w rupture spleen requires a
splenectomy
124
what happens when someone gets a splenectomy
leaves person susceptible to future infections and premature death
125
what maintains army of monocytes for release when needed
lymphocytes, macrophages of white pulp monitoring blood for foreign antigens
126
