Transcript Human Anatomy & Physiology II

THE CARDIOVASCULAR
SYSTEM: BLOOD
FUNCTION
Transportation-hormones, gasses, nutrients, ions,
heat
 Regulation- pH, temperature, water balance in
cells
 Protection- clotting, white cells interferons,
complement

COMPOSITION
Connective tissue-Two parts
 Plasma = soluble materials (~55%)


Remove the clotting proteins in plasma= serum
Formed Elements = cells (~45%)
 Percent occupied by red blood cells (RBC) =
hematocrit (Hct)
 White blood cells (WBC) ~1%

FIGURE 14.1A
FIGURE 14.1B
PLASMA
 ~91% water, 7% proteins, 1.5 % other solutes
Proteins: Albumin (54%)- osmosis and carriers;
 Globulins (38%)- antibodies
 Fibrinogen (7%)- clotting
 Other: Electrolytes , nutrients, gases, hormones,
vitamins & waste products

FORMED ELEMENTS
I. Red Blood Cells
II. White blood cells

A. Granular Leukocytes
1.
2.
3.
Neutrophils
Eosinophils
Basophils
B. Agranular leukocytes

1.
2.
T & B lymphocytes & natural Killer cells
monocytes
III Platelets- thrombocytes
FORMATION OF BLOOD CELLS
Called hemopoiesis
 Just before birth and throughout life occurs in
red bone marrow
 Contains pluripotent stem cells
 In response to specific hormones these develop
through a series of changes to form all of the
blood cells

FIGURE 14.2A
FIGURE 14.2B
ERYTHROCYTES (RBCS)
Hemoglobin- carries oxygen
 Also carries some CO2
 Male has ~ 5.4 million cells/µl; Female has ~4.8
million
 membrane, no nucleus, flexible structure
 use glucose for ATP production to maintain ionic
composition
 No mitochondria
 Wear out fast- live ~120 days

RBC CYCLING
Cleared by macrophages (liver & spleen)
 Fe- recycled in bone marrow


Carried in blood on transferrin
Heme bilirubin and excreted (bile)
 Globin A.A. recycled.

FIGURE 14.3
RBC SYNTHESIS
Called erythropoiesis
 From stem cells: hemocytoblasts
 Released as reticulocytes
 Mature to erythrocytes in 1-2 days
 Production & destruction is balanced
 Low O2 delivery (hypoxia) 
 erythropoietin release (EPO) from kidney
 Stimulates erythropoiesis

FIGURE 14.4
LEUKOCYTES (WBC)
Defenses: phagocytes, antibody production and
antibacterial action
 Phagocytes:
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Neutrophil- first responders
Monocytes macrophages (big eaters)
Eosinophil- phagocitize antibody-antigen complexes Involved
in suppressing allergic responses
Immune response:
 Lymphocytes

T-cells, B-cells& natural killer (NK) cells

*Basophil- intensify allergic reactions (not a phagocyte)
WBC LIFE SPAN
5000-10,00 WBC /µl blood
 Limited number of bacteria can be eaten
 Life span is a few days
 During active infection may be hours
 Leukocytosis= increased WBC numbers
response to stresses
 Leukopenia = decreased WBC numbers

PLATELETS
Myeloid stem cells  megakaryocytes  2000 3000 fragments = platelets
 Plug damaged blood vessels
 Promote blood clotting
 Life span 5-9 days

HEMOSTASIS
Hemostasis = the stoppage of blood
 1. Vascular reactions (spasm)
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2. platelet plug formation
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Become sticky when contact damaged vessel wall
3. blood clotting (coagulation)

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Response to damage
Quick reduction of blood loss
Series of chemical reactions involving clotting factors
Clotting in unbroken vessel= thrombosis
COAGULATION

Extrinsic pathway common steps
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
tissue factor(TF) from damaged cells 1
Intrinsic Pathway  common steps

Materials “intrinsic” to blood 1
1. prothrombinase which causes
 2. prothrombin thrombin causes
 3. fibrinogen  fibrin  clot

CLOT RETRACTION & VESSEL REPAIR
Clot plugs ruptured area
 Gradually contracts (retraction)
 Pulls sides of wound together
 Fibroblasts replace connective tissue
 epithelial cells repair lining

CONTROL MECHANISMS
Fibrinolysis: dissolving of clot by activated
plasmin enclosed in clot
 Clots can be triggered by roughness on vessel
wall = thrombosis
 Loose clot = embolus and can block a small
vessel = embolism

FIGURE 14.5
BLOOD TYPES
Surface antigens- react with antibodies
 Divided into groups based on antigens
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> 24 blood groups and > 100 different antigens
We will deal with ABO and Rh groups
ABO GROUP
Two antigens = A & B
 Type A- if have only A
 Type B- if have only B
 Type AB- both antigens
 Type O- if neither then
 Blood usually has antibodies that can react with
antigens
 e.g. anti-A antibody or anti-B antibody
 You don’t react with your own antigens
 Thus: type A has anti-B and vice versa

FIGURE 14.6
RH BLOOD GROUP
Antigen discovered in rhesus monkey
 If have antigen- Rh+
 Normally don’t have antibodies
 antibodies develop after the first exposure from
transfusion

TRANSFUSIONS
If mismatched blood given antibodies bind to it
and hemolyze cells
 Type AB has no AB antibodies so can receive any
ABO type blood called Universal recipients
 Type O have neither antigen so can donate to any
other ABO type called Universal donors
 Misleading because of many other blood
groups that must be matched
