Lecture 9 Flashcards
What does white blood cell count measure?
leukocytes in the blood
What does high white blood cell count indicate?
bacterial infections, autoimmune diseases, side effects of medications
What does low white blood cell count indicate?
viral infections, pneumonia, autoimmune diseases, cancers
What is immunity?
ability to ward off disease
What is susceptibility?
lack of resistance to a disease
What is innate immunity?
defenses against any pathogen
- rapid, present at birth
What is adaptive immunity?
resistance to a specific pathogen
- slower to respond, has memory component
Where do toll-like receptors attach?
pathogen-associated molecular patterns
Why do TLRs bind to PAMPs?
induces release of cytokines from the host cell that regulate the intensity and duration of immune responses
What are the 2 main layers of skin and its function?
- dermis: inner portion with connective tissue
- epidermis: outer layer of skin with keratin (protective protein)
What cell is in epidermis?
epithelial cells
Why do we shed skin?
inhibits microbial growth
What are mucous membranes?
epithelial layers that lines GI, respiratory, and tear ducts
What is mucus?
viscous glycoproteins that trap microbes and precent tracts from drying out
What are lacrimal apparatus?
drains tears and washes eye
What do ciliary escalators do?
transports microbes trapped in mucus away from the lungs
What is the purpose of earwax?
prevents microbes from entering the ear
What is the function of urine?
cleans out the urethra
What is the function of vaginal secretions?
moves microorganisms out of the vaginal tract
What is the function of sebum?
protective film
- lowers pH of skin
What is the function of lysozymes in perspiration, tears, saliva, and urine?
destroys bacterial cell walls
What is the function of gastric juice?
pH of 1.2-3 destroys most bacteria and toxins
What are the 3 main way for normal microbiota to compete with pathogens?
- competitive advantage for space and nutrients
- produces substances harmful to pathogens
- alter conditions that affect pathogen survival
What is commensalism?
one organism benefits while the host is unharmed
What is the function of lactic acid bacteria?
inhibits growth of certain pathogens
colonize in large intestine to alleviate diarrhea
What cells are found in plasma?
erythrocytes (RBC)
leukocytes (WBC)
platelets
Where is plasma made? What’s the process called?
red bone marrow stem cells
- hematopoiesis
What are granulocytes?
leukocytes with granules in their cytoplasm visible with a light microscope
What are the 3 types of granulocytes and their functions?
- neutrophils: phagocytic, work in early stages of infection
- basophils: release histamines, work in allergic responses
- eosinophils: phagocytic, toxic against parasites and helminths
What are agranulocytes?
leukocytes with granules in their cytoplasma that aren’t visible with a light microscope
What are the 3 examples of agranulocytes and their function?
- monocytes: mature into macrophages in tissues where they are hagocytic
- dendritic cells: found in the skin, mucous membranes, thymus; phagocytosis
- lymphocytes: T cells, B cells, NK cells; adaptive immunity
What are natural killer cells?
immune cell in the innate immune system
What do NK cells do? What is their key role?
attach any cell that display abnormal or unusual plasma membrane proteins
- recognizes and destroys infected or cancerous cells by releasing toxic substances that induce cell death
What are lytic granule?
sensory organelles specific to NK cells
- can contain perforin
What is cytolysis?
extra cellular fluid flows into the cell and it bursts
What are granzymes?
protein digesting enzymes that induce the target cell to undergo apoptosis
What is apoptosis?
programmed cell death
Why are natural killer cells better than T and B cells?
They don’t require prior exposure to an antigen
- rapid first line of defense against tumors and viral infections
What are T cells?
type of white blood cell that plays a central role in the immune system
What is the functions of T cells?
- help directly attack infected or cancerous cells
- regulate immune responses
- assist other immune cells
What are B cells?
white blood cell responsible for producing antibodies that target specific pathogens
What is the function of B cells?
- humoral immune response
- recognizing antigens and generating a targeted defense by creating antibodies to neutralize or destroy invading microbes
What is leukocytosis?
increase in white blood cell count during infections as a protective response to combat microbes
What diseases can cause leukocytosis?
- meningitis
- appendicitis
- gonnorrhea
What is leukopenia?
decrease in white blood cell count
What can leukopenia result from?
- impaired white blood cell production
- increased sensitivity of white blood cell membranes
What is the differential white blood cell count?
measures percentage of each type of white blood cell in a sample of 100 white cells to detect increases or decreases in specific leukocyte populations
What are lymphs?
fluid that flows through lymphatic system
- contains lymphocytes and phagocytic cells
What does lymphoid tissue have that participate in immune response?
T cells, B cells, phagocytic cells
What are lymph nodes?
sites of activation of T cells and B cells which destroy the microbes by immune response
What is the function of lymph?
carries microbes to lymph nodes where lymphocytes and macrophages destroy the pathogen
What is phagocytosis?
ingestion of microorganism or substance by a cell
- clears away debris and denatured proteins
What are macrophages?
developed granulocytes and monocytes that come to the infected area
What are fixed macrophages?
residents in tissues and organs
What are free macrophages?
roam tissues and gather at sites of infection
What is the mechanism of phagocytosis?
1) Chemotaxis: chemical signals attract phagocytes to microorganisms
2) Adherence: attachment of a phagocyte to the surface of the microorganism
3) Ingestion: opsonization - microorganism is coated with serum proteins to make ingestion easier
4) Digestion: eaten inside a phagolysosome
5) Elimination: exocytosis and discharge of waste materials
What is residual body?
fatal lysosome with indigestible material
- moves toward cell boundary and discharges its waste outside the cell
