Anatomy/Physiology Lecture
Circulatory System
ELEMENTS OF THE BLOOD:
I.
Erythrocytes (RBC)
a. Formation of blood = hemopoeisis; bone marrow
i. Structure: biconcave disc (8 nm)
ii. No nucleus or organelles
iii. Semi-permeable membrane, cytoplasm,
hemoglobin (carries O2)
b. Function: combines with O2 and CO2 and transports
them
i. 4 heme groups (non-protein pigments) contain
iron
1. Iron attaches to O2
ii. 4 globin groups (identical proteins)
1. Globin attach to CO2
c. General Information:
i. There are approximately 700x more RBC than
WBC
1. (4.8 million RBC/mm3 blood in females)
2. (5.4 million RBC/mm3 blood in males)
ii. Life Span: ~120 days due to wear and tear
experienced in the capillaries (very tight fit;
nearly single file)
1. Broken down in liver, spleen and marrow
2. Heme groups are broken down in to iron and
biliverden
iii. Origin (production)
1. Erythropoeisis- formation of RBC
2. Occurs in red bone marrow
3. Rate of formation = rate of destruction
a. If not, condition called anemia occurs
(not enough RBC in the system)
II.
Leukocytes: White blood cells (WBC)
a. Structure:
i. Have a nuclei and lack hemoglobin
1. Either granular or a granular
b. Function:
i. Defense system; remove antigens (foreign
particles) by either phagocytosis or initiating
antibody (Ab) production
ii. Immune response: eosinophils- pro-inflammatory
releasing enzymes (histamine) causing
inflammation: allergic reactions
iii. Antibody response: block binding sites on cells,
thus inhibiting antigen-cell interaction (no
response)
c. General Information:
i. ~5,000 to 10,000 WBC/mm3 of blood
ii. presence of more (10,000+) reflects the presence
of infection
iii. less than 5,000 cells = leukopenia;
immunocompromization (can’t fight off
infections)
iv. Live only a few days (during infections live only
hours)
v. Produced in the white marrow of the bones
III.
Thrombocytes (platelets)
a. General Information
i. Disc-shaped; no nucleus; possess granules
ii. Sole purpose: CLOT BLOOD
iii. Live ~5-9 days
iv. 250,000-400,000/mm3 blood
v. Produced in the red bone marrow
IV. Plasma- consists of “everything else” (water, hormones,
proteins, nutrients, electrolytes, etc.)
a. Primary Proteins:
i. Albumen:
1. produced in liver
2. 55% of all plasma proteins
3. purpose: maintain water balance between
blood and tissues
ii. Globulins:
1. produced by B cells/plasma cells
2. 35% of plasma proteins
3. purpose: antibodies against foreign particles
iii. Fibrinogen:
1. produced in the liver
2. 7% of plasma proteins
3. purpose: blood-clotting factors
The Circulatory System: Part II
Homeostasis: maintaining balance in the body; optimum levels
the processes of the body that enable optimum conditions to be
maintained for all cells, in spite of continual changes taking place
both internally and externally.
Whenever an imbalance occurs, regulatory systems become active
to restore the optimum conditions, usually by a process known as
negative feedback. When there is a break from the normal levels,
the body is detects the variations and initiates changes which bring
the level back to where it should be.
MOMMY, WHY DON’T I BLEED TO DEATH?
I.
Mechanisms
a. Vascular Spasms: contraction of smooth wall
immediately following damage
i. Primary response; reduces blood loss (between
minutes and hours) until other mechanisms kick in
ii. Induced by reflex mechanisms associated with
pain receptors
b. Platelet Plug Formation: swelling of platelets in
damaged vessels
i. Irregular shapes (more surface area; greater
adherence to walls)
ii. Become sticky and adhere to collagen fibers of
wounded area; works well in small wounds
iii. Tightens with coagulation (stretching of a scab)
c. Coagulation:
i. thickening and forming a gel (serum) that is
different than plasma; forms the CLOT (reference
page 314)
d. Vascular Disorders:
i. Plaque: cholesterol-containing mass found in the
tunica media of the arteries
ii. Thrombus: gel clot composed of insoluble protein
fibers
iii. Embolism: piece of debris (thrombi or plaque)
breaks off and moves through vasculature until
caught in small vessels
1. pulmonary embolism- occurs in the lungs
iv. anti-coagulant: prevent clotting
1. heparin (mast cells/basophils)
2. inhibits prothrombin from maturing into
thrombin
THE FLAVORS OF OUR BLOOD
II.
Blood Typing: determined by surface molecules found on
the RBC; contain genetically determined antigens called:
*ethnicity plays a factor in blood types
a. Agglutinogens: 14 types/systems but the top two are
ABO and Rh
i. ABO: based on agglutinogens called A and B
ii. Blood plasma contains A or B (anti-A or anti-B)
1. A has A (plasma has anti-B antibodies)
2. B has B (plasma has anti-A antibodies)
3. AB has A and B (universal recipient; AB+ to
be exact)
a. (plasma has neither anti-A or B
antibodies)
4. O has neither (universal donor; (O- to be
exact)
a. (plasma has both anti-A and B
antibodies)
b. Blood transfusions with different blood types is BAD
i. Causes blood to clump
ii. Cells swell and rupture (hemolysis = BAD)
1.
2.
3.
4.
A gets A or O
B gets B or O
AB gets A, B or O
O gets O only
c. Rh Factor: named for Rhesus monkey (Macaca
mulatto)
i. Rh protein may be present or absent in individuals
ii. Presence of Rh factor = Rh+
iii. Absence of Rh factor = Rhd. Understanding the Rh factor
i. Mr. Hoefer is (A-); A blood type, lacking the Rh
protein
1. Can donate to A+, A-, AB+, ABa. Application: from above, why is AB+
better than AB- when receiving blood?
b. Why is O- better than O+ when
donating blood?
It is particularly important for expectant mothers to know their
blood's Rh factor. Occasionally, a baby will inherit an Rh positive
blood type from its father while the mother has an Rh negative
blood type. The baby's life could be in great danger if the mother's
Rh negative blood attacks the baby's Rh positive blood. If this
happens, an exchange transfusion may save the baby's life. The
baby's blood can be exchanged for new blood that matches the
mother's.