A&P II Chapter 21 Lymphatic and Immune System Flashcards Preview

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Flashcards in A&P II Chapter 21 Lymphatic and Immune System Deck (40)
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1
Q

What is lymph

A

clear, colorless fluid, similar to plasma but much less protein; looks milky after a fatty meal

2
Q

Functions of Lymphatic Systems

A

• Fluid recovery (helps to maintain fluid balance)
– absorbs plasma proteins and fluid (2 to 4 L/day) from tissues and returns it to the bloodstream
─ interference with lymphatic drainage leads to severe edema
• Immunity (protect body from infection and disease)
– fluids from all capillary beds are filtered through lymph nodes
– immune cells stand ready to respond to foreign cells or chemicals encountered
• Lipid absorption
– Lacteals (special lymphatic vessels) in small intestine absorb dietary lipids

3
Q

Components of Lymphatic System

A

Lymph, Lymphatic Capillaries/Vessels, Lymphatic Tissue (variety of lymphocytes & other cells), and Lymphatic Organs

4
Q

Route of Lymph Flow :
Example – lymphatic capillaries -> collecting vessels -> ——————– ->
Right and Left Subclavian Vein

A

lymphatic capillaries collecting vessels (course through many lymph nodes) lymphatic trunks (6 of these drain major portions of body) collecting ducts (2 of these form from the convergence of the 6 trunks).

5
Q

E. Mechanisms of lymph flow

A
  • Lymph flows at low pressure and speed
  • Moved along by rhythmic contractions of lymphatic vessels-stretching of vessels stimulates contraction
  • Flow aided by skeletal muscle pump, thoracic pump
  • Valves prevent backward flow
6
Q

F. Name of Lymphatic Cells

A

• T lymphocytes (T cells)
– Mature in thymus
• B lymphocytes (B cells)
– Activation causes proliferation and differentiation into plasma cells that produce antibodies (gamma/γ globulins)
• Antigen Presenting Cells (phagocytize and present antigenic material to T cells to alert immune system)
– macrophages (from monocytes)
– dendritic cells (in epidermis, mucous membranes and lymphatic organs)
– reticular cells (also contribute to stroma of lymph organs)

7
Q

G. Name of Lymphatic tissue

A
  • Diffuse lymphatic tissue: lymphocytes in mucous membranes and CT of many organs
  • Lymphatic nodules: dense oval masses of lymphocytes, congregate in response to pathogens; Peyer patches: more permanent congregation, clusters found at intestines.
8
Q

H. Name of Lymphatic organs
Function of lymph node and spleen

What is lymphadenopathy and lymphadenitis

A

• Lymph nodes
– cervical, axillary and inguinal regions close to surface, • Only organs that filter lymph•Two functions: cleanse the lymph & alerting the immune system

– thoracic, abdominal and pelvic groups deep in cavities
• Tonsils
– guard entrance to pharynx
• Thymus
– between sternum and aortic arch
• Spleen
– inferior to diaphragm, dorsolateral to stomach, largest lymphatic organ, – blood production in fetus
– blood reservoir
– RBC disposal – “erythrocyte graveyard” for old, fragile RBCs
– immune reactions: filters blood, quick to detect antigens (lymph node does lymph)

• Lymphadenopathy is a collective term for all lymph node diseases
─ lymphadenitis is inflammation of lymph node - swollen, painful node that is
responding to foreign antigen
─ lymph nodes are common sites for metastatic cancer - swollen, firm, and usually
painless

9
Q

I. Defenses against Pathogens
a) Nonspecific defenses: External barriers/Leucocytes and Cutaneous Defenses/Antimicrobial Proteins/Inflammation (Purpose, Cardinal signs, Major processes)/Fever

A

Defenses Against Pathogens (toxins, living orgs, & other agents that cause disease)
• Nonspecific defenses - broadly effective, no prior exposure (read the 1st para, P.808):
– external barriers: skin, mucous membrane etc
– phagocytic leukocyte cells, antimicrobial proteins, inflammation and fever
• Specific defense - results from prior exposure, protects against only a particular pathogen - immune system

A) Nonspecific defenses
i) External Barriers
• Skin
– dry and nutrient-poor, defensins (peptides from neutrophils) attack microbes
– lactic acid (acid mantle) is a component of perspiration – inhibits bacterial growth
• Mucous membranes: stickiness of mucus, lysozyme: destroys bacteria
• Subepithelial areolar tissue: viscous barrier

10
Q

b) Specific Defense (Immunity) -> Immune System, Characteristics, Forms of Immunity, other classifications

A

• Immune system – not an organ system but is about a group of widely distributed cells that recognize and destroy alien substances
• 2 characteristics: Specificity (directed against a particular pathogen) and
Memory (remembers pathogen - allows quick response)
• 2 forms: Cellular immunity: cell-mediated (T cells directly attack suspicious cells)
Humoral immunity: antibody mediated (B cells)
• Other classifications: Passive & Active and Natural & Artificial Immunity
 Natural active immunity (produces memory cells)
– production of one’s own antibodies or T cells as a result of infection or natural exposure to antigen
 Artificial active immunity (produces memory cells)
– production of one’s own antibodies or T cells as a result of vaccination [Vaccine: dead or attenuated (weakened) pathogen – stimulate immune response but no disease]
 Natural passive immunity (through placenta, milk)
– temporary, fetus acquires antibodies (Ab) from mother
 Artificial passive immunity (for the treatment of snakebites, rabies, tetanus)
– temporary, injection of immune serum (Ab) from another individual or animal who was exposed to a certain pathogen

11
Q

c) Antigens (Epitopes/Haptens)

A

Large complex molecules (can be free or part of cell membrane) that can trigger an immune response

Epitopes or antigenic determinants: certain regions of the molecule that stimulate an immune response

Haptens: molecules too small to stimulate immune response but binds to host macromolecule which initiates an immune response

12
Q

d) Lymphocytes (Types of Lymphocytes) -> T Lymphocyts and B Lymphocytes

A

 Specific immunity depends on lymphocytes & macrophages
 Types of lymphocytes in circulating blood
– 80% T cells (cell mediated)
– 15% B cells (antibody mediated)
– 5% NK cells (nonspecific immunity)

13
Q

e) Interleukins (Types)

A

Hormone like chemical messengers (cytokines) between leukocytes
2 types:
 Lymphokines: produced by lymphocytes
 Monokines : produced by macrophages

14
Q

f) Cellular Immunity ( 4 Classes of T Cells involve)

A

• T lymphocytes attack and destroy foreign cells and diseased host cells
• Involves 4 classes of T cells:
 Cytotoxic or killer (not NKs) T cells (TC): carry out attack on enemy cells
 Helper T cells (TH): help TC cells and in humoral immunity(B cell action)
& nonspecific defense mechanisms
 Suppressor T cells (TS): limit cell mediated attack and keep the system
under control; TH & TS are regulatory cells – accelerate or stop TC actions
 Memory T cells: forms from TC cells, responsible for memory - provide
immunity from future exposure to antigen

Both cellular and humoral immunity occur in 3 stages:

15
Q

g) Stages of Immunity

A

• Recognition (Fig: 21.23)
– B cell receptors bind antigen, take in and digest them, and then display the antigen fragments
– TH cell binds to B cells and secrete helper factors, B cell divides repeatedly, differentiate into plasma cells, produce antibodies specific to that antigen
• Attack
– antibodies released from plasma cells bind to antigen, render it harmless, ‘tag it’ for destruction (by neutralization, complement fixation, agglutination, & precipitation); note that the destruction is not by directly destroying the antigen, rather covering its pathogenic sites and marking it for destruction by other agents.
(Fig: 21.24 – plasma cell)
• Memory
– some B cells differentiate into memory cells

16
Q

h) Humoral Immunity

A
  • B lymphocytes of humoral immunity does not directly attach to enemy cells, rather produces antibodies (also called an immunoglobulin or Ig) that bind to antigens and tag them for destruction
  • Works in 3 stages (the 3 Rs of immunity)
17
Q

i) Types of Antibodies – Example of sites

A

• Immune system produces as many as 2 million different antibodies
• Somatic recombination
– DNA segments shuffled and form new combinations of base sequences to produce antibody genes

18
Q

Hypersensitivity (Allergy) -> Definition, Types of Hypersensitivity, Antibodies involved

A

• Excessive, harmful immune reaction against antigens that most people tolerate
• Reactions include:
 reactions to tissues transplanted from another person (alloimmunity)
 abnormal reactions to one’s own tissues (autoimmunity)
 reactions to environmental antigens called allergens (allergies)

19
Q

J. Autoimmune Diseases – Why autoimmune disease occurs? Example of autoimmune diseases (see Type III hypersensitivity)

A

• Failure of self tolerance
– Immune system fails to distinguish “self” and “nonself” antigens and produces autoantibodies that attack own body tissues. Three possible reasons are:
– cross-reactivity: an Ab formed against a bacteria may attack other host cell
– abnormal exposure of self-antigens: breakage in bl barriers exposes self antigens that are not otherwise exposed
– changes in structure of self-antigens: viruses, drugs may change self-antigens causing the immune system to consider those as “nonself”

• Type III Hypersensitivity (Immune Complex)
− IgG or IgM forms antigen-antibody complexes that gets deposited between layers
of tissues and trigger intense inflammation and tissue necrosis (acute
glomerulonephritis and in systemic lupus erythematosus)

20
Q

Immunodeficiency Diseases -> Why it occurs?

AIDS/HIV, level of helper T cells in the blood, signs/symptoms/HIV transmission

A

immune system fails to respond vigorously enough
• Severe Combined Immunodeficiency Disease (SCID)
– hereditary lack of T and B cells
– highly vulnerable to opportunistic infection

Signs and symptoms
– early symptoms: flulike chills and fever
– progresses to night sweats, fatigue, headache, extreme weight loss, lymphadenitis
– normal TH count is 600 to 1,200 cells/L of blood but in AIDS it is < 200 cells/L
• person susceptible to opportunistic infections (Toxoplasma, Pneumocystitis, herpes simplex virus, CMV or TB
– thrush: white patches on mucous membranes may appear
– Kaposi sarcoma: cancer originates in endothelial cells of blood vessels causes purple lesions in skin

• Through blood, semen, vaginal secretions, breast milk, or across the placenta
• Most common means of transmission
– sexual intercourse (vaginal, anal, oral)
– contaminated blood products
– contaminated needles
• Not transmitted by casual contact
• Undamaged latex condom is an effective barrier to HIV Treatment Strategies
• HIV is evolving resistance to the “triple cocktail”

21
Q

The only lymphatic organ with both afferent and efferent lymphatic

A

lymph node

22
Q

Which cell are involved in nonspecific resistance but not in specific denfense

A

natural killer cells

23
Q

The respiratory burst is used by what to kill bacteria

A

neutrophis

24
Q

which is a macrophage

A

a microglial cell

25
Q

the cytolytic action of the complement system is most similar to the action of what

A

perforin

26
Q

what becomes antigenic by binding to larger host molecules

A

Haptens

27
Q

Name the order of the humoral immunity

A
endocytosis of an antigen
antigen display
secretion of interleukin
clonal selection and
antibody secretion
28
Q

the cardinal signs of inflammation include what

A

redness
swelling
heat
pain

29
Q

A helpter T cell can bind only to another cell that has

A

MHC-II proteins

30
Q

Which results from a lack of self tolerance

A

systemic lupus erthematosus

31
Q

any organism or substance capable of causing disease is called

A

Pathogen

32
Q

Mucous membranes contain an antibacterial enzyme called

A

Lysozyme

33
Q

What condition in which one or more lymph nodes are swollen and painful to the touch

A

lymphadentis

34
Q

The movement of leukocytes through a capillary or venule wall is called

A

Diapedesis emigration

35
Q

in what process complement proteins coat bacteria and serve as binding sites for phagocytes

A

Opsonization

36
Q

Any substance that triggers a fever is called

A

purogen

37
Q

The chemical signals produced by leukocytes to stimulate other leukocytes are called

A

Interleukins

38
Q

Part of an antibody called the_______binds to part of an antigen is called___________

A

antigen binding site and epitope

39
Q

self tolerance results froma a process called ________in which lymphocytes programmed to react against self antigens die.

A

Clonal deletion

40
Q

Any disease in which antibodies attack ones own tissue is called a______disease

A

autommune