integument and immune systems

Question 1

what is the integument system

Answer 1

• initial barrier to infection and prevents a alrge proportion of environmental microorganisms from entering the body
• composed of hair, skin, nails: physical barrier preventing enterance of pathogens

Question 2

what is the skin microbiome

Answer 2

• many microorganisms live on surface of human skin and make up the normal skin flora
• participate in mutualism (benefits both organism and human)
• they prevent more harmful organisms from occupying the same space and organisms get a stable environment and acess to nutrients

*can become pathogenic if they penetrate the integument

Question 3

how does skin act as a nonspecific defense mechanism

Answer 3

• protects against pathogenic invasion
• sebaceous glands in the skin secrete oil onto the surface of skin to keep pH relatively acidic to decrease bacterial growth
• also helps keep the skin moist
• sweat is secreted from other glands to help cool skin by evaporation, also contains enzymes that help destroy bacterial cell walls and pheromones used in chemical communication amoung humans

Question 4

what are the different layers of skin

Answer 4

• dermis and epidermis connected by basement membrane
• demis contains blood supply and most of the specialized cells
• epidermis mainly containes keratinocytes which differentiate into protective, waterproof cells that do not undergo further replication (roughly sloughed off and replaced

Question 5

what is the role of hair on skin

Answer 5

• aids direct sweat and waste away from from the skin
• helps with evaporative cooling but can also trap heat to prevent body from being too cool
• serves as a sensory organ to detect nearby motion

Question 6

what is the role of muscous and nails on integument system

Answer 6

• muscous secretions in nose and other squeous secretions in eyes preent forgein organisms from entering the body and resist infection
• eznymes in the mouth and troat break down many entering microorganisms and decrease their pathogenicity
• nails protect the tip of the giners and toes from physical injury

Question 7

what is the role of the immune system

Answer 7

• destruction of internal pathogens
• body can recognize nonself qualities in other cells (antigens) allowing it to recognize pthogens that have prevously been encountered to produce a quicker immune response

Question 8

what are the 2 major types of immunity

Answer 8

• humoral = antibody production
• cell mediated = cells that combat fungal and viral infections

Question 9

what is the inflammatory response

Answer 9

• non specific defense mechanism
• white blood cells activated releasing histamine that causes teh immune response
• it dilates and increases the permeability of blood vessels which inc the flow of white blood cells and other immune cells to affected area

*allows body to more effectively ward off infection

• inflammation often accompanied by rise in body temperature (fever) -> kills temp dependent pathogens (benefit of fever still debated)

Question 10

what is the lymphatic system

Answer 10

• found in extravascular space of most tissues
• lymph flows through lymphatic vessels from lymph node to lymph node
• lymph nodes and spleen serve as reservoirs of white blood cells and filters for lymph
• removes antigen presenting cells and foreign matter, activates immune system when required

Question 11

what is the other name of white blood cells, what are teh different types

Answer 11

leukocytes

• types: Basophil, Eosinophil, neutrophils, monocytes and lymphocytes

*bas, eos and neu are all granulocytes

Question 12

what are granulosites

Answer 12

• attracted to the site of injury where they phagocytize antigens and antigenic material
• include neutrophils, eosinophils and basophils

Question 13

what are neutrophils

Answer 13

• most common type of granulocyte
• first responders to sites of inflammation, attracted to cytokines which causes attraction of white blood cells once arrive at damage tissues
• particularly adapted to attack bacteria
• neutrophil counts are elevated during acute stages of infalmmation and are the main component of pus

Question 14

what are eosinophils

Answer 14

• much less common and responsible for immune responses, especially asthmatic and allergic response
• elevated eosinophil ocunt on a complete blood count (CBC) inducates an allergic response or infection by parasite

Question 15

what are basophils

Answer 15

• basophils and related mast cells are involved in allergic responses and parasitic infections
• responsible for release of histamine which stimulates blood vessel dilation

Question 16

what are monocytes

Answer 16

• large long-lived immune cells that differentiate into macrophages and dendritic cells
• main role is to phagocytize dead cells and pathogens
• is pathogen is ingested the antigens are present on the durface of the macrophage to stimulate other immune cells to mount a specific immune response to the invading pathogen
• dendritic cells are more focused on processing antigens and presenting them to other immune cells: serve as links between the innate and adaptive immune systems

*found in areas where exposure to external env more common (skin, intestine, mucous membrane)

Question 17

what are T lymphocytes

Answer 17

• imp for specific immunity
• through rearrangement of chains that compose its antigen receptors T cells become reactive to only one antigen type presented be a major histocompatability complex
• majority of t cells created are subsequently deactivated and undergo apoptosis c will not react ith MHC or react to well and would attack self cells
• suffiencent amoung still remain and protect

Question 18

what are the 2 types of MHC and the types of T cells assoicates

Answer 18

• MCH I and MCH II
• Cytotoxic T cells (T_c, also called CD8+ T cells) recognize antigens presnt on MHC 1
• these complexs come from cells infected with viruses or developing tumors and signal T_c cells to destroy those
• T helper cells (T_h, CD4+ T cells), recognize antigens on MHC II
• activated T_H cells release cytokines to stimualte the immune resposne causing toher WBC to mature and attack

**natural killer T cells (NKT) behave similarly to T_C and T_H but respond to antigens presented by other cell types

Question 19

what is the role of memory T cells and suppressor T cells

Answer 19

• Memory T cells reactive to the same antigens are formed and remain in circulation of long periods of time allowing a quicker and more atget response if antigen reappears
• suppressor serve to tone down T cell response to self callls or following an infection

Question 20

where are t cells developed and where do they travel to

Answer 20

• development begins in bone marrow where T lymphocyte precurser cells are formed
• travel via blood to thymus where they mature (this is wehre the T comes from)
• once maturation is complete cells are released into lymph

Question 21

T cell levels in aids patients

Answer 21

• have very low levels of certain types of T cells and are subject to infection bc immune system is weaker

Question 22

what are B lymphocytes, where are they formed/mature

Answer 22

• when stimulated they create and express antibodies (known as immunoglobulins) that have high affinity for the antigen expressed by the stimulating T lymphocytes
• the immunoglobulins have specific strucutre that aids in targeted destruction of pathogens
• b cells also stimulate the formation of memory cells, also begin developemnt in bone marrow

**travel to other parts of the body to mature

Question 23

types of granulocytes and function

Answer 23

Basophils: only 1%, fight parasites and mediate allergic resposne

Eosinophils: 5%, fight parasites and mediate allergic response

Neutrophils: 94%, phagocytic

Question 24

what are the types of monocytes

Answer 24

Macrophages: phagocytic, secrete cytokines, present antigens

Dendritic cells: present antigens, activate immune system

Question 25

what are the types of lymphocytes

Answer 25

B cells: produce antigen specific antibodies

T cells:

• Helper T cells activate other immune cells
• Cytotoxic CD8+ cells and antural killer T cells destroy cels marked for destruction
• memory T cells remain acter infection so response can occur more quickly

Question 26

wht is humoral immunity

Answer 26

• immune system contains componets that are not cells: various chemicals, hormones and eznymes to help the action of the cells

Question 27

what are antibodies and general strucutre

Answer 27

• large proteins secreted by B cells that provide a specific targeted response to a given antigen
• several types exist within the immune system but have relatively the same structure
• looks like a Y, has a antigen binding sites at top, each side has heavy and light chain held together by disulfide bonds
• antibody binding region is the variable portion, diff antigen binding sites allows immune response against number of antigens

*also called immunoglobulins

Question 28

what are the two types of antibody mediated immunity

Answer 28

• active and passive

Question 29

describe active immunity

Answer 29

• occurs as result of immune response
• can be due to expsoure to a pathogen or antigen such as during an infection or result of vaccination
• features of antigen are stoes in non self memory allowing the body to mount a similar immune response should antigen present itself again
• requires development of cells specifc to particular antigen and can take weeks to build up

Question 30

what is passive immuntiy

Answer 30

• aquired by the transfer of antibodies from one individual to another
• can occur during pregnancy from placenta or injections of gamma globulin (fraction of blood containing antibodies)
• effective immediately but once antibodies no longer circulating effect of immunity is lost

Question 31

what is innate immunity

Answer 31

• comprised of bodies inital generalized defenses against pathogens
• does not require cells of the immune system to be previously exposed to any antigen to be activated
• not a specifc response and body is limited in types of immune response it can mount

includes:

anatomic features (like integument),

physiological response (fever, PH change, enzymes),

phagocytic cells (monocytes, meutrophils and macrophages),

inflammation

Question 32

what is adaptive immunity

Answer 32

• acquired or specific immunity consisting of cells capable of recognizing self vs non self cells
• actiivty of cells that participate is increased with each expsoure
• cells involved include: lymphocytes (T and B cells), plasma cells, antigen presenting cells (macrophages and B cells)

Question 33

example of how adaptive and innate immunity works together

Answer 33

• works together to protect the host and defend against invading pathogens
• phagocytic cells (innate) can stimulate the production of specific T lymphocytes 9adaptive) to assist in killing and destruction
• T lymphocytes in turn can release cytokines whcih increase the killing activities of phagocytes

Question 34

explain transplant rejection

Answer 34

• transplanted tissues and organs are detected as non cells
• antigen son donated ogan are those of donor
• immune system targets the transplanted organ
• can lead to rejection: destruction of organ or death of patient
• immunosupressing drugs are used to loer immune response t dec lieklihood of rejection
• patient is then immunocompromised