Chapter 20 Flashcards
(78 cards)
1
Q
what is the lymphatic system
A
- group of organs and tissues that works with the immune system to protect the body from pathogens
- also participates in a other fuctions
2
Q
what are the main components of the lymphatic system
A
- a system of lymphatic vessels
- lymphatic tissue and lymphoid organs
3
Q
what are lymphatic tissues and organs
A
clusters of lymphoid follicles
- tonsils
- lymph nodes
- spleen
- thymus
4
Q
what are the functions of the lymphatic system
A
- regulation of intersitial fluid volume
- absorption of dietary fats
- immune functions
5
Q
how does the lymphatic system control regulation of interstitial fluid volume
A
- net filtration pressure in blood capillaries favours filtration so water is lost from plasma membrane to the intersitial fluid (about 2-4 L/day)
- lymphatic vessels pick up intersitial fluid and deliver it back to the cardiovascular system
- when intersitial fluid enters the lymphatic vessels it is known as lymph
6
Q
how does the lymphatic system control absorption of dietary fats
A
breakdown of dietary fats enter small lymphatic vessels in the small intestine and are delivered to the blood with lymph
7
Q
how does the lymphatic system control immune functions
A
lymphoid organs filter pathogens from the lymph and blood, house some leukocytes too
8
Q
how does lymph circulation work
A
- no pump to drive circulation
- lymphatic vessels make up a low pressure circuit
- transporting against gravity
- lymphatic valves prevent backflow
- often found between muscles where contraction pushes lymph toward the heart
- tiny lymphatic capillaries form weblike networks around blood capillaries
- lymph moves away from tissues
- endothelial cells in the wall flap open and closed
9
Q
what prevents backflow in lymph circulation
A
lymphatic valves
10
Q
A
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Q
A
12
Q
A
13
Q
what are lymphatic capillaries
A
- tiny weblike networks around blood capillaries
- where intersitial fluid enters to lymph vessels
14
Q
how do solutes go from the blood to the lymphatic system
A
15
Q
What is mucosa-Associated Lymphatic Tissue
A
(MALT)
loosely organized clusters of lymphoid tissue protecting mucous membranes exposed to large numbers of pathogens
16
Q
where is MALT found
A
- gastrointestinal tract
- respiratory passages
- genitourinary tract
17
Q
what kinds of cells are in MALT
A
most clusters of B cells and T cells, no connective tissue capsule
18
Q
in the gastrointestinal tract, where is MALT found
A
- tonsils
- oral and nasal cavities
- small intestine ileum
- appendix (off the large intestine)
19
Q
what are the types of tonsils
A
- pharyngeal tonsil (posterior nasal cavity)
- palatine tonsils (posterorlateral oral cavity)
- lingual tonsil (base of the tongue)
20
Q
what are tonsillar crypts
A
indents lining the tonsils
21
Q
what do tonsillar crypts do
A
- trap pathogens
- may cause inflammation or tonsillitis
22
Q
what does the appendix do
A
defends against bacteria in the large intestine
23
Q
how does appendicitis happen
A
bacteria and fecal matter become trapped in the appendix
24
Q
what are lymph nodes
A
small bean shaped clusters of lymphatic tissue located along lymphatic vessels throughout the body
25
what are the clusters of lymph nodes
- axillary lymph nodes
- cervical lymph nodes
- inguinal lymph nodes
- mesenteric lymph nodes
26
where are axillary lymph nodes located
armpit region
27
what lymph nodes are in the armpit region
axillary lymph nodes
28
where are cervical lymph nodes located
neck region
29
what lymph nodes are in the neck region
cervical lymph nodes
30
where are inguinal lymph nodes located
groin region
31
what lymph nodes are in the groin region
inguinal lymph nodes
32
where are mesenteric lymph nodes located
abdominal cavity around the abdominal organs
33
what lymph nodes are in the abdominal cavity around the abdominal organs
mesenteric lymph nodes
34
describe the structure of lymph nodes and surrounding area
each has an external connective tissue capsule surrounding reticular fibers filled with macrophages, lymphocytes, and dendritic cells
35
what is the largest lymphoid organ in the body
spleen
36
describe the structure of the spleen
- network of reticular fibers with two distinct regions
- red pulp and white pulp
37
what is red pulp
reticular fibers containing macrophages that destroy old erythrocytes
38
what is white pulp
reticular fibers that contains leukocytes and filters pathogens from the blood
39
what does white pulp surround
central arteries
40
what is the structure around central arteries in the spleen
zone around is mostly T cells
outside the zone are lymphoid follicles with a core of B cells
outer rim of white pulp are macrophages, dendritic cells, some B and T cells
41
what is the thymus
- small, encapsulated organ with two lobes
- secretes hormones that generates a population of functional T cells
42
what are t cells
43
at what age is the thymus at its biggest size
12-14
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how does the size of the thymus change as you age
45
what are the lines of defense in the immune system
1. cutaneous and mucous membranes
2. responses of the cell and proteins - innate immunity
3. responses of the cells and proteins - adaptive immunity
46
what is the first line of defense of the immune system
involves cutaneous and mucous membranes that act as surface barriers to block pathogen entry into the body
innate immunity
47
what is the second line of defense of the immune system
consists of responses of the cells and proteins that make up the category of defenses we call
innate immunity
48
what is the second line of defense of the immune system
consists of the responses of the cells and proteins that make up the category of defenses we call
adaptive immunity
49
what is innate immunity
responds to all pathogens or classes of pathogens in the same way
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what is adaptive immunity
adaptive/specific/acquired
responds to individual unique markers called antigens
54
what is an antigen
- any substance capable of generating a response from the immune system
- present on all cells and most biological molecules
- identify a cell or molecule as belonging to a specific group
55
what is cell-mediated immunity
brough tabout by two types of T cells
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what is antibody-mediated (humoral) immunity
carried out by B cells and the proteins they produce (antibodies)
57
what is immunological memory
- exposure to an antigen is "remembered" by specific lymphocytes and antibodies
- not possible with innate immunity
58
what surface barriers are part of the innate immune system
- skin
- mucous membrane
- sebum
- mucus
59
how is skin a surface barrier
- covers nearly every external surface of the body
- relatively resistant to mechanical stress with several layers of epitheleum and the hard protein keratin
60
how is the mucous membrane a surface barrier
- lines all passages in the body that open to the outside, including respiratory, gastrointestinal, genitoury tracts
- epithelia lack keratin and are generally thinner than skin epithelia
61
how is sebum a surface barrier
- sebaceous glands secrete sebum
- oily mixture with a slightly acidic pH that deters growth of pathogens
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how is mucus a surface barrier
- mucous membranes produce mucus
- a thick, sticky substance that traps debris and pathogens
- protects underlying cells from chemical and mechanical trauma
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how is stomach acid a surface barrier
- mucosa of the stomach secretes acid
- kills ingested pathogens
64
how is cilia a surface membrane
- propels substances out of the respiratory tract
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how are defensins a surface barrier
- skin and mucosae cells produce defensins
- antimicrobial peptides that damage membranes of pathogens
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how is a person's normal flora a surface barrier
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what are agranulocytes
68
what are the types of immune cells
69
what are granulocytes
70
what are natural killer (NK) cells
71
*do not cover proteins in immune system
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