Lecture 26- Blood/Immunity Flashcards
Plasma
Pale yellowish, many components
Mostly H2O
Salts-dissolved ions
Osmotic balance
Composition of interstitial fluid
Function of plasma proteins
Regulate fluid in plasma vs. interstitial fluid
Albumins
Plasma proteins that regulate pH, osmotic balance
Immunoglobulins
Plasma proteins that are antibodies- defense
Apolipoproteins
Plasma proteins that do lipid transport
Fibrinogens
Plasma proteins that do clotting (serum= plasma w/o fibrinogens)
Substances transported in plasma
Nutrients
Wastes (CO2)
Gases (O2)
Hormones
Where/how is blood produced?
Bone marrow
Multipotent stem cells divide -> one stays stem, one specializes
Ribs, vertebrae, sternum, pelvis
What are the three groups of blood cells?
Red blood cells- erythrocytes
White blood cells- leukocytes
Platelets
Erythrocytes
Red blood cells (RBCs)
Most numerous
Flexible biconcave discs
No nuclei- more space for hemoglobin
No mitochondria- anaerobic metabolism
Specialized for O2 transport (O2 insoluble in aqueous solutions)
Hemoglobin
Leukocytes
White blood cells (WBCs)
Specialized for defense against pathogens
Not confined to circulatory system- interstitial fluid, lymph nodes
Platelets
Not whole cells- Formed via pinching fragments of large cells in bone marrow
No nuclei
Involved in clotting
Platelet Plug Formation
Temporary clot
Blood vessel damaged
-> Vessel constricts
-> Platelets stick to collagen fibers
-> Platelets release attractants
-> More platelets stick
Fibrin Clot Formation
Fibrin clots are stronger, permanent
30 clotting factors involved
From platelets, damaged cells, plasma
Clotting factors, calcium, platelet compounds are a cascade that activates prothrombin into thrombin. Prothrombin is a plasma protein from liver, requires vitamin K. Thrombin catalyzes fibrinogen (soluble) into fibrin (insoluble). Sticky, gooey fibers make a net over the break and catch platelets and red blood cells, make a big mass of cells and fibers that block the break in the blood vessel.
Platelet plug vs. Fibrin clot
Platelet plug is temporary and faster, fibrin clot is slower and permanent.
Hemophilia
1 clotting factor missing or defective
Anticlotting Factors and thrombus
Prevent spontaneous clotting in the absence of damage
Thrombus- clot within blood vessels, can block flow
Purpose of immune system
Protects against pathogens, foreign molecules
What are the two types of defense systems?
Innate immunity and adaptive immunity
Adaptive Immunity
Acquired immune response
Specific response to specific antigens
Innate Immunity
General protection against pathogens
Barrier Defenses
Innate immunity
Non-specific “anatomical” barriers
- Prevent entrance
- Physical and chemical
Examples of Barrier Defenses
Skin (integumentary system)- Not penetrable by bacteria, viruses
- Habitat for commensal bacteria
- Chemical barrier- oil and sweat glands- pH 3-5
Mucous lining- Mucus is viscous, traps pathogens
- Digestive, urinary, respiratory, reproductive tracts
- Ciliated epithelial cells
Lysozyme: destroy bacterial cell walls
Stomach
Pathogens ingested-> destroyed by stomach acid
Cellular Innate Defenses
Destroy pathogens that get in
What are the two types of Cellular Innate Defenses?
Phagocytic cells and Natural Killer cells
Phagocytic cells
Ingest pathogens via phagocytosis
Often found in lymphatic system- lymph nodes during infection
Have Toll-like receptors (TLR)
- Bind molecules characteristic of pathogens, absent from vertebrates
Phagocytic Cell Activity-SEQ process of phagocytic cells
- Pseudopodia surround pathogens
- Pathogens engulfed by endocytosis
- Vacuole forms
- Vacuole and lysosome fuse
- Pathogens destroyed
- Debris from pathogens released
Natural Killer (NK) Cells
Circulate through body
Recognize abnormal surface proteins- indicate virus infection, cancer
Release chemicals- trigger cell death
Do not directly attack pathogens
Interferons
Secreted by virus-infected cells
Do not save infected cell, help other resist infection
Complement system
30 proteins in plasma
Circulate inactive- activated by surface proteins of microbes
-> lysis of invading cells
Local Inflammatory Response
Activated by tissue damage-> heat, redness, edema, pain
Histamines + cytokines released, capillaries dilate
WBCs recruited, antimicrobial peptides released
Pathogens digested, tissue heals
General Inflammatory Response
Inflammation can involve whole body
-> Fever: Change in set point temp of body to facilitate immune response
- Raises body temp
- Increases phagocytosis
- Interferes with pathogens
