Function of the Circulatory System Chpt 14 [1st part] sorry about
margins no time to reformat
1] Transportation - distribution of substances
a] Gas exchange -
O2 transported from lungs to cells for aerobic resp., hemoglobin
in erythrocytes
CO2 transported in plasma from cells to lungs for release in
exhaled air
b] Nutritive - nutrient molecules absorbed by the gut are transported
in plasma
to liver and all cells of the body
c] Excretory - wastes, excess water and ions or organics transported
in plasma
to kidney (and skin) for removal
2] Regulation
a] contributes to temperature control
b] distributes hormones
3] Protection
a] protects against invasion of foreign matter/organisms
b] maintains liquid volume via clotting mechanism
c] provides immune rx against pathogens
Major Components of CS
1] Cardiovascular system
a] heart - pumps 5L blood/min; 5.5L total vol
b] blood vessels - tubular network through which fluid flows
arteries -- arterioles -- capillaries -- venules -- veins
c] blood - fluid tissue; plasma and formed elements
2] Lymphatic system
a] lymphatic vessels
b] interstitial fluid - lymph
c] lymph nodes - filtration sites; sites of lymphocyte production
[lymphoid organs: Peyer's patches, tonsils, thymus and spleen]
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Blood
To distinguish components a sample of whole blood may be centrifuged F
14-1
Hematocrit - % of volume occupied by erythrocytes;
45% - 52 m , 37 - 48% f
Buffy layer - thin layer of leukocytes and platelets; < 0.5 %
Plasma - noncellular liquid; 48 - 63% vol
Blood values
Volume 80 - 85ml/kg body wt; H2O - 93%
Osmolarity 280 - 296 mOsm
pH 7.35 - 7.45
Plasma constituents
gases, nutrients, wastes, electrolytes (elaborated in T 14-1 -
know)
hormones
testosterone: m 300 - 1100 ng/100ml; f 25 - 90 ng/100ml
insulin : 2-26uU/ml (fasting)
clotting factors
enzymes
essential vitamins like folic acid, B complex
plasma proteins: % of total
albumins - 60 %, syn by liver, major osmotic component
drawing water
into capillaries to maintain blood vol and pressure
globulins - 36%, includes
alpha and beta - syn in liver, bind to and transport ions
and other mols.
gamma - antibodies produced by lymphocytes
fibrinogen - 4%, syn in liver, required for clot formation
transferrin - transports iron [iron balance F 3]
Formed elements T 3
Erythrocytes: biconcave disk, 7um in diam
contain hemoglobin - Fe in heme group reversibly binds O2 and a
little CO2
anucleate cell in circulation, 3-4 mo life span
membrane glycoproteins (20+) convey antigens for blood typing
in adult produced in marrow of long bones
Leukocytes: nucleated cells; diapedesis; distinguished by staining
charac.
Agranulocytes:
Monocytes - largest, kidney-shaped nuc.; precursor of
macrophages and
osteoclasts
Lymphocytes - prod in bone marrow and thymus; small cell
with little cytopl.;
give rise to plasma cells which prod antibodies
Granulocytes - contents of small vesicles have affinity for
different dyes
Neutrophils - polymorphs - multilobed nucleus, granules
lightly stained
Eosinophils - granules stain deep red
Basophils - granules stain very dark blue
Platelets - thrombocytes, cell fragments having receptors which
trigger clotting
Blood cell production - hematopoiesis F 6
Pluripotent stem cells - retain capacity to divide; some progeny
directed into
specific cell lines
HGFs and erythropoietin