Ch 1 1 blood and body defenses

Blood

8% bw, 5-6 liters in the body, has RBCS, WBCS, and platelets in plasma`

erythrocytes/RBCs

o2 transport 45%, no nucleus, organelles, or ribosomes, biconcave discs that allow for more surface area for o2, and its thin that diffusion is easy, membrane is flexible and allows rbcs to travel wo rupturnig

WBCs/Leukocytes

Immune system mobile defense units 1%, recognizes and destroys or neutralizes materials wi body that are foreign to self, defends against pathogens, identifies and destroys cancer cells, functions as a clean up crew, colorless, slighlty bigger than rbc

Plateletes/thrombocytes

cell fragments of megakaryoctes- lack nuclei, have organelles and enzymes a lot of actin and mysosin, important in homeostasis 55%, last abt 10 days and removed by tissue macrophages.

Neutrophils

A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease. release a trap that contains chemicals that kill bacteria, first defenders, important for inflammation, scavenge to clean up debris, most abundant 60-70%

Eosinophils

Attack parasitic worms, play a role in allergic reactions like asthma and hayfever, 1-4 percent of wbcs

basophils

releases histamine- helps in allergic reaction and heparin-clear fat from the blood, simialr to mast cells, 0.25-0.5 percent,

monocytes

are in transit to become macrophages

Plasma proteins

albumins- most abundant, globulins=Alpha, beta, gamma, fibrinogen- blood clotting

hemoglobin

iron contaning pigment, reddish when ox, bluish when deox. Two parts- globin- protein of 4 highly folded poly peptide chains, heme groups- 4 iron containing non protein groups each one bound to one of the poly peptides, goal is to carry o2, but smtimes carries other stuff

Erythropoiesis

rbc production, rbcs last abt 120 days, spleen removes most of old erythrocytes from circulation, must be replaced at a rate bw 2-3mill cells/sec. Erythropoiesis occurs in bone marrow- pluripotent stem cells in red bone marrow diff into the diff types of blood cells

Anemia

below normal o2 carrying capacity of the blood, characterized by low hematocrit

Pernicious anemia

lack of mature erythrocytes caused by inability to absorb vitamin B12 into the bloodstream

Aplastic anemia

failure of blood cell production in the bone marrow

renal anemia

Lack of EPO

Often accompanies renal disease

Treated with synthetic EPO

hemorrhagic anemia

caused by blood loss

hemolytic anemia

reduction in red cells due to excessive destruction

polycythemia

A disorder characterized by an abnormal increase in the number of red blood cells in the blood

Primary polycythemia

casued by tumor like condition of bone marrow, erythropoiesis proceeds at an uncontrolled rate.

Secondary Polycythemia

erythropoietin induced adaptive mechanism to improve blood oxygen carrying capacity in response to prolonged reduced oxygen delivery to tissues, ex. ppl living in high altitudes.

Blood types

classified according to the presence, or absence, of certain antigens; four major blood types are A, AB, B, and O

How are platelets releases

about 1/3 are stored in spleen released when needed by sympathetically induced splenic contraction

thrombopoietin

hormone from liver stimulates platelet formation, and megakaryocytes

Hemostasis

prevents blood loss from a broken blood vessel, involves vascular spasm, formation of a platelet plug, and blood coaugulation

vascular spasm

reduces blood flow thru a damaged vessel

formation of a platelet plug

activated platelets become sticky once they touch collagen and adhere to the defect form a temporary plug as they release adp that makes the surface of nearby platelets become sticky to adhere to the first layer of aggregated platelets

blood coaugulation (clotting)

blood from liquid to a solid gel

Clot formation

reinforces platelet plug and converts bblood plasma into gel, clotting factors are always present in blood in inactive precursor form, vessel damage that exposes collagen inititaes cascade of events that involve activation of clotting factors. Converts fibrinogen to fibrin- intrinsic clotting pathway

Clotting cascade

series fo steps involing 12 plasma clotting factors that lead to final conversion of fibrinogen to fibrin mesh. may be triggered by intrinisc or extrinsic pathway

intrinsic pathway

7 steps, set off when factor 12/xii (hageman factor) is activated by coming in contact w exposed collagen in injured vessel or foreign surface

extrinsic pathway

4 steps, requires contact w tissue factors external to the blood, tissue thromboplastic released from traumatized tissue directly activates factor x

thrombus

stationary blood clot

embolus

A clot that breaks lose and travels through the bloodstream.

hemophilia

A hereditary disease where blood does not coagulate to stop bleeding, a lack of a clotting factor

granulocytes

neutrophils, eosinophils, basophils

agranulocytes

lymphocytes and monocytes

what wbc are made in red bone marrow

all except lymphocytes they are produced by lymphocyes alr in lymphoid tissues such as lymph nodes and tonsils

B lymphocytes

produce antibodies, responsible for antibody mediated or humoral immunity

T lymphocytes

no antibodies, directly destroy target cells by releasing chemicals that punch holes in the victim cell, target cells include body cells invadedby viruses and canver, clonal and antigen specific- get receptors from thymus

innate immunity

inflammation, interferon, NKC, complement system

inflammation

non specific response to tissue injury, bring phagocytes and plasma proteins to invaded or injured area, reddness, heat, swelling, pain

Glucocorticoids

suppress almost all parts of inflammtion and bodys ability to resist infection

interferon

Protein produced by cells in response to being infected by a virus; helps other cells resist the virus.

Natural killer cells

lymphocyte like cells, nonspecifically destroy virus infected and cancer cells, mode of action- directly breakdown membranes upon first exposure to these cells

complement system

A group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse extracellular pathogens.

Antibody mediated or humoral immunity

involves production of antibodies by B lymphocyte derivatives known as plasma cells

cell mediated immunity

type of immunity produced by T cells that attack infected or abnormal body cells

antigen

large foreign unique molecule, induces an immune response against itself, in general the more complex the more foreign

B cell how it works

Each B cell can recognize one specific threat.

When it finds that threat (the antigen), it gets activated.

Most B cells then become plasma cells, which make antibodies.

Some become memory cells to help fight future infections faster.

ANtibodies

y shaped molecules, 4 poly peptide chains, 2 long and 2 short, properties of tail determine the functional properties of the antibody, identical antigen binding fragments at tip of each arm unique for each antibody, tail (constant region) regions wi each subclass are identical,

What can antibodies do?

neutralize harmful chemicals, bind to foreign cells enhance ither defense systems

immune complex disease

Immune Complex Disease happens when your immune system goes overboard:

It forms too many antigen-antibody complexes.

The body can't clear them fast enough.

These complexes keep triggering inflammation.

That leads to damage to your own healthy tissues.

active immunity

self gen, results from antigen exposure

passive immunity

borrowed immunity, results from transfer of preformed antibodies, immediate protective or bolster resistance, ex. transfer of IgG antibodies from mother to fetus

killer t cells

Lymphocytes that use enzymes to destroy the cell membranes of bacteria and other foreign invaders.

helper t cells

Activate macrophages, B cells and T cells.

MHC molecules

plasma membrane bound glycoproteins that present antigens to T cells., synthesis is directed by group of genes called major histocompaatibility complex, exact pattern of mhc molecules varies from one to another

immune system tolerance

Immune system learns to discriminate self from non-self. The immune system needs to recognize what to attack and what not to attack.

autoimmune diseases

Diseases caused when the immune system loses tolerance for self and turns against certain molecules in the body.

immune surveillance

process by which t cells recognize and destroy newly arisen and potentially cancerous tumor cells

tumor

clone of cells identical to origianal muatted cell can be benign or malignant, most genetic mutations do not lead to cancer

immunodeficiency diseases

-Too little immune response

-Examples: Severe combined immunodeficiency, AIDS

inappropriate immune attacks

too much or mistargeted immune response

allergy

abnormal hypersensitivity acquired by exposure to an antigen, offended agent is an allergen can be immediate or delayed

immediate hypersensitivity

(type I) IgE-mediated mast cell degranulation caused by crosslinking of surface IgE by antigen

delayed hypersensitivity

T cell-mediated inflammatory reaction that takes 24-72 hours to reach maximal intensity

external defenses

skin- epidermis and dermis

epidermis

melanocytes, keratinocytes, langerhans cells, granstein cells

melanocytes

produce melanin which protects skin by absorbing uv

keratinocytes

The most abundant epidermal cells, they function mainly to produce keratin, secrete interleukin 1

langerhans cells

special macrophages that serve as antigen-presenting cells in the skin

granstein cells

suppress skin-activated immune responses

dermis

blood vessels, nerve endings, exocrine glands sebaceous- maek sebum which softens and waterproofs the skin and sweat glands