Circulatory System- Blood

Created by SailorJohnEdward 

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What are the functions of blood?

-Transports all necessary fluids, gases, chemicals, nutrients, and wastes throughout the body
- Protection; WBCs, antibodies, and platelets
- Regulation of fluid and buffering

What are the properties of blood?

- Viscosity
- Osmolarity

What is Viscosity?

Resistance to flow

What is Osmolarity?

Total molarity of dissolved particles
- sodium ions, protein, and RBCs
High Osmolarity - causes fluid absorption into blood, raises BP
Low Osmolarity - causes fluid to remain in tissues, may result in edema

What are the three major categories of plasma proteins?

-Albumins (most abundant; contributes to viscosity and osmolarity, influences blood pressure, flow, and fluid balance)
- Globulins (antibodies; provide immune system functions such as gamma globulins are antibodies)
- Fibrinogen( precursor of fibrin threats that help form blood clots)

what is plasma?

a solution of water and solutes

What is formed elements?

-RBCs: carry oxygen and some carbon dioxide
-WBCs: important in immunity, allergic responses, antibody production and inflammation
- Platelets: essential for hemostasis

What is Serum?

Remains after plasma clots; Fibrinogen is NOT in serum

What is are nitrogenous compounds?

(Nonprotein)
-amino acids
-nitrogenous wastes (urea)

What the function of Erythrocytes (RBCs)?

- Gas transport (major function); increased surface area and volume ratio no nucleus or mitochondria
- Carbonic anhydrase (CAH); produces carbonic acid from CO2 and water; important role in gas transport and pH balance

What is a hematocrit?

% of whole blood composed of RBCs

Why are RBCs and Hemoglobin lower in women?

-adrogens stimulate RBC production
-periodic mestrual losses
-hematocrit inversely proportional to percent body fat

Hemopoiesis

the production of new blood cells,
-stimulated by a # of chemical messengers in response to alterations in body homeostasis

Where are plasma proteins made by?

mostly in the liver; except globulins produced by plasma cells

What does the bone marrow produce?

RBCs, WBCs, and platelets

Hemopoietic

tissues where new blood cells are produces

yolk sac

produce stem cells; colonize fetal bone marrow,liver, spleen and thymus

Spleen is involved?

with WBC production

Erthrocyte Homeostasis

Negative feedback control
- drop in RBC count causes kidney hypoxemia
- EPO production stimulates bone marrow
- RBC count increases in 3-4 days

What stimulates erythropoiesis?

-low levels of O2
- increase in exercise
- loss of lung tissue in emphysema

What are the nutritional needs for erythrocyte production?

- Iron (for hemoglobin production)
- Vitamin B12 and folic acid
- Vitamin C and copper (cofactors for enzymes synthesizing RBCs

EPO

stimulates the development of the proerythroblast into an erythroblast

Hemoglobin

a protein that consists of four polypeptide chains called globins.
Each heme group, bound to iron, can then bind to an oxygen molecule

How many oxygen molecules can a one hemoglobin bind to?

One hemoglobin molecule can bind to a maximum of 4 oxygen molecules.

What is polycythemia?

an excess of RBCs

Primary polycythemia

Cancer of erthropoietic cell line in red bone marrow
RBC count is high as 11

Secondary polycythemia

from dehydration, emphysema, high altitude, or physical conditioning

What is globin?

a polypeptide

What is Anemia and causes of it?

Inadequate erthropoiesis or hemoglobin synthesis (decreased production)
- kidney failure and insufficient erythropoietin

pernicious anemia

- inadequate vitamin of B12 from poor nutrition or lack of intrinsic factor

Hemorrhagic anemias

loss

Hemolytic anemias

increased destruction; Body destroying RBCs

Sickle-cell Disease- homozygous

Hereditary Hb 'defect'
-recessive allele modifies hemoglobin structure
- individual has shortened life

Sickle-cell trait

heterozygous for HbS - individual has resistance to malaria

Leukocytes (WBCs)

responsible for defense from microorganisms and other pathogens.

What are the 2 types of Leukocytes?

- Grandulocytes (Neutrophils, Eosinophils, Basophils)
- Agranulocytes (lymphocytes, monocytes)

Neutrophils

Increases in bacterial infections
-phagocytosis of bacteria
-release antimicrobial chemicals (hydrogen peroxide)

Eosinophils

Increase in parasitic infections or allergies
-phagocytosis of antigen-antibody complexes, allergens and inflammatory chemicals
-release enzymes to destroy parasites

Basophils

Increase in chicken pox, sinusitis, diabetes
-secrete histamine
-secrete heparin

Lymphocyes

Increase in diverse infections and immune responses
- destroy cancer cells
- "present" antigens to activate other immune cells
- coordinate actions of other immune cells
- secrete antibodies and provide immune memory

Monocytes

increase in viral infections and inflammation
- differentiate into marcrophages
- phagocytize pathogens and debris
- "present" antigens to activate other immune responses

Leukopenia

Low WBC count
causes: radiation, poisons, infectious diseases
effects: elevated risk of infection

Leukocytosis

High WBC count
Causes: infection, allergy and disease
Differential count -distinguishes % of each cell type

Leukemia

Cancer of hemopoietic tissue
-myeloid and lymphoid- uncontrolled WBC production
- acute and chronic- death in months or 3 years
Effects: normal cell % disrupted; impaired clotting

Platelets

Responsible for hemostasis; aid in vascular constriction, platelet plug formation, and coagulation.
-phagocytize bacteria
-chemically attract neutrophils and monocytes to sites of inflammation

thrombopoiesis

Production of platetes

Megakaryoblasts

(started out as Stem cells)
-repeatedly replicate DNA w/o dividing cytoplasm
-forms gigantic cell called megakaryocyte

Megakaryocyte

Infoldings of cytoplasm splits off cells fragments that enter bloodstream as platelets

Hemostasis

homeostatic mechanism that prevents the loss of blood due to trauma or other damage to blood vessels

What are the 3 stages of Hemostasis?

1. Vascular Spasm
2. Platelet Plug
3. Coagulation

Vascular spasm

promote the prompt constriction of a broken blood vessel.
-pain receptors (short duration-minutes)
-smooth muscle injury(longer duration)
-platelet release serotonin (vasoconstrictor)
-provides time for other two-clotting pathways

Platelete Plug Formation

Endothelium smooth, coated with prostacyclin
-broken vessel exposes collagen
-platelet pseudopods stick to damaged vessel and other platelets- pseudopods contract an draw walls of vessel togethere forming a platelet plug
- Platelets degranulate releasing serotonin (vasoconstrictor), ADP (attracts and degranulates more platelets), Thromboxane A
- positive feedback cycle is active until break in vessel is sealed

Clotting

conversion of plasma protein fibrinogen into insoluble fibrin threads to form framework of clot

Coagulation

-clotting
-Procoagulants (clotting factors) are present in plasma
-extrinsic pathway: factors released by damaged tissues begin cascade
-intrinsic pathway: factors found in blood begin cascade (platelet degranulation)

Hemophilia

Genetic lack of any clotting factor affects coagulation
- Sex-linked recessive
- physical exertion causes bleeding and excruciating pain

Embolism

clot traveling in a vessel

Thrombosis

abnormal clotting in unbroken vessel- likely to occur in leg veins of inactive people

Pulmonary embolism

clot may break free, travel from veins to lungs

Infraction

occurs if clot blocks blood supply to an organ

Thrombus

inappropriate clot inside vessel

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