PSIO Exam 3

Question 1

Lymphatic System Functions

Answer 1

• drain excess interstitial fluid
• transport dietary lipids
• carry out immune responses

Question 2

Primary Lymphatic Organs

Answer 2

• red bone marrow

- thymus

Question 3

Secondary Lymphatic Organs and Tissues

Answer 3

• lymph nodes
• spleen
• lymphatic nodules/follicles

Question 4

Lymphatic Vessels

Answer 4

• drain excess ISF and return it to the blood stream

- originate in “close ended” lymph capillaries, which lie adjacent to blood capillaries in the tissue space

Question 5

Lymphatic Capillaries

Answer 5

• slightly larger than blood capillaries

- have one way valves

Question 6

Lymph Nodes

Answer 6

found at irregular intervals along the lymph vessels

Question 7

Non-Specific Resistance

Answer 7

the body’s lines of defense against invasion by pathogen (ie. bacteria, viruses, fungi, and environmental hazards)

Question 8

Non-Specific defenses include:

Answer 8

• physical barriers (first line of defense)
• fever
• inflammation
• cells and chemicals

Question 9

Physical Barriers to pathogenic invasion

Answer 9

• skin
• mucus membranes
• hairs and cilia
• acid
• tears

Question 10

Skin as a Physical Barrier

Answer 10

sebaceous glands, sudoriferous glands (sweat glands), and lysosome

Question 11

Mucus Membranes as a Physical Barrier

Answer 11

mucus is secreted by specialized epithelial cells called goblet cells

Question 12

Hairs and Cilia as a Physical Barrier

Answer 12

mucus-coated hairs, cilia on specialized epithelial cells that line trachea

Question 13

Acid as a Physical Barrier

Answer 13

the pH of the stomach is about 2.0

Question 14

Tears as a Physical Barrier

Answer 14

also contain lysosome

Question 15

Fever

Answer 15

• abnormally high body temperature in response to invading microorganisms
• the body’s thermostat is reset upwards in response to PYROGENS (chemicals secreted by leukocytes and macrophages exposed to bacteria and other foreign substances)
• high fever is dangerous because it can denature enzymes

Question 16

How can moderate fever be beneficial

Answer 16

• the liver and spleen sequester iron and zinc (needed by microorganisms). The combination of raised fever and lowered iron inhibits bacterial growth.
• an increase in the metabolic rate, which speeds up the repair of tissues
• triggers production of interferons

Question 17

Inflammation

Answer 17

The inflammatory response is triggered whenever body tissues are injured

• prevents the spread of damaging agents to nearby tissues
• disposes of cell debris and pathogens
• sets the stage for repair processes

Question 18

4 Cardinal Signs

Answer 18

1. redness
2. heat
3. swelling
4. pain

Question 19

Cells and Chemicals White Blood Cell Types

Answer 19

• eosinophils
• basophils
• neutrophils
• lymphocytes
• monocytes

Question 20

Cells and Chemicals White Blood Cells Function

Answer 20

WBCs enhance the innate defenses by:

• attacking microorganisms directly
• hindering the ability of microorganisms to move, grow, reproduce, etc.

Question 21

Cells: Neutrophil Function

Answer 21

1. Fastest responders to bacteria
2. Direct actions against bacteria
   - release lysosomes to digest bacterial cell walls
   - release defense proteins that act like antibiotics and form pores in bacterial cell membranes, destroying them
   - release strong oxidants (e.g. H2O2) that destroy bacteria

Question 22

Cells: Basophil Function

Answer 22

Exit capillaries at sites of inflammation and play a role in allergic reactions
-release heparin, histamine, and serotonin which heighten the inflammatory response and can often contribute to hypersensitivity (allergic) reactions

Question 23

Cells: Eosinophils Function

Answer 23

• respond to and attack parasitic worms
• enter ISF and releases histaminase (slows down inflammation caused by basophils)
• able to phagocytize antibody-antigen complexes

Question 24

Cells: Lymphocyte Function

Answer 24

1. Most types involved in adaptive immunity
   - B lymphocytes
   - T lymphocytes
2. Natural killer (NK) cells are involved in innate immunity
   - attack many different microbes directly
   - attack spontaneously arising tumor cells

Question 25

Cells: Monocyte Function

Answer 25

Arrive later to sites of infection, but arrive in much larger numbers - destroy microbes and clean up dead tissue following an infection - become wandering macrophages in ISF

Question 26

Cells and Chemicals: Natural Killer (NK) Cells

Answer 26

1. NK cells are a specialized class of T-lymphocytes which perform generalized functions - kill tumor cells - kill some virus infected cells 2. NK cells kill via CYTOLYSIS - secrete a chemical known as perforin, which perforates the cell membrane 3. Reduces NK cell counts can be associated with HIV/AIDS

Question 27

Cells and Chemicals: Antimicrobial Proteins

Answer 27

1. Like WBCs, antimicrobial proteins enhance innate defenses 2. Specifically, antimicrobial proteins: - (also) attack microorganisms directly - hinder the ability of some microorganisms to reproduce 3. The two most important types of antimicrobial proteins are: - interferons - complement proteins

Question 28

Antimicrobial Proteins- Interferons

Answer 28

- interferons are proteins that are produced by virus-infected body cells, T lymphocytes, natural killer cells and macrophages - interferons and other chemical messengers that alter cellular activities are called cytokines - the action of interferons is non-specific, meaning that they work effectively against a large number of virus types

Question 29

The Complement System

Answer 29

- refers to over 30 specific proteins that "complement" or enhance the action of antibodies - complement proteins attach to antibody-antigen complexes - the end result of attachment is the formation of membrane attack complex (MAC) which punches holes in bacterial cell membranes (attraction of phagocytes, stimulation of phagocytosis, and inflammation are also the result of complement activation)

Question 30

C3 can be activated via:

Answer 30

1. classical pathway 2. alternative pathway 3. lectin pathway

Question 31

Innate Immunity (non-specific resistance to disease)

Answer 31

Lines of defense against invasion of pathogens: 1. physical barriers 2. fever 3. inflammation 4. cells and chemicals

Question 32

Adaptive Immunity

Answer 32

- Body's ability to recognize and defeat a specific invading agents such as bacteria, viruses and foreign tissues - Distinguished from innate immunity by two properties 1. Specificity for particular foreign molecules (foreign antigens) and tolerance for self proteins 2. Memory of previously-encountered foreign antigens so that the 2nd exposure prompts a more rapid and vigorous response

Question 33

Molecular Information in Residual Bodies:

Answer 33

1. things present in extracellular fluid | 2. if what was destroyed is something truly foreign

Question 34

Peptide fragments >8 amino-acids in length

Answer 34

human and bacterial protein sequences can be distinguished from each other

Question 35

MHC Proteins

Answer 35

- immune system's ID and anti-privacy/surveillance system | - display information in the form of peptides (pieces of protein) to the immune system

Question 36

Function of MHC Class II Proteins

Answer 36

- present small fragments of protein called processed antigen to the cells of the immune system - presented antigen is from protein components of materials engulfed and digested by phagocytes (MHC II displays extracellular antigen)

Question 37

Helper T cells

Answer 37

have T cell receptors whose job it is to interact with MHC II- presented antigen

Question 38

Random Sampling (every nucleated cell randomly samples the proteins in its cytoplasm and does the following)

Answer 38

1. digests the protein into small peptide fragments of 8-15 amino acids in length 2. displays those fragments on MHC I 3. as if to say "here is a sample of what proteins I am making"

Question 39

>8 amino-acids in length

Answer 39

human and bacterial protein sequences can be distinguished from each other

Question 40

Function of MHC I proteins

Answer 40

- present small fragments of protein called "processed antigens" to the cells of the immune system - presented antigen is from randomly-sampled proteins inside of cells (MHC I displays intracellular antigen)

Question 41

Cytotoxic T cells

Answer 41

have T cell receptors whose job it is to interact with MHC presented antigen