Download Major Concepts of Anatomy and Physiology

The Circulatory
System - Blood
Part 4: Regulation &
Maintenance
Circulatory System

Circulatory System aka Cardiovascular
System: Responsible for transportation!
 Blood
transports nutrients & oxygen through
the vessels, powered by the heart muscle.
Blood Elements

Formed Elements: Solid elements that
make up 45% of blood volume.
 Red
Blood Cells
 White Blood Cells
 Platelets

Plasma: Clear fluid in which formed
elements are suspended, make up 55% of
blood volume.
Blood Properties

Two important properties of blood:
 Viscous:
Nearly 5 times more viscous (thick)
than water.
 Osmolarity: The concentration of osmotic
solution helps regulate the passage of
materials into and out of the blood.
Plasma

Plasma Components:




Albumins: Proteins produced by the liver, responsible
for maintaining osmolarity; influence blood pressure,
flow, and fluid balances.




90% water
7% enzymes, nutrients, wastes, hormones, gases, & proteins
3% miscellaneous, including amino acids, nitrogenous wastes,
and some carbon dioxide & oxygen.
Also act as transport proteins for hormones & fatty acids.
Globulins: Produced by plasma cells that help with
transport (Alpha & Beta Globulins) and immunity
(gamma globulins).
Fibrinogen: Produced by the liver & is the essential
element for blood clotting.
Sodium: Important for blood pressure & volume.
Formed Elements



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Red Blood Cells (RBCs) aka Erythrocytes:
Primary mode of transport for oxygen & carbon
dioxide; make up the majority of formed
elements.
White Blood Cells (WBCs): Immune cells – will
be discussed later!
Platelets: Cell fragments that help in blood
clotting.
Buffy Layer: Layer of WBCs, platelets, & RBCs
in the bottom of a tube of blood fresh from the
centrifuge.
Red Blood Cells

Erythrocytes aka Red Blood Cells (RBCs): Blood
element responsible for transporting oxygen shaped like
biconcave discs.


Hemoglobin: Protein within the RBCs that allows for
gas transportation.


Shape allows for rapid diffusion throughout the cell due to
increased surface area.
Iron: Metal critical for hemoglobin production & oxygen
transportation.
Life Cycle:


2,500,000 produced per second.
Just over 100 day life cycle – when worn out they lyse and are
cleaned up by microphages in the spleen, liver, & bone marrow.
Red Blood Cells

Red Blood Cell Count varies based on
altitude & is measured in cells per
microliter:
 Males:
4.7 to 6.1 million cells per microliter.
 Females: 4.2 to 5.4 million cells per microliter.

RBCs outnumber WBCs 700 to 1.
Hemopoiesis

Hemopoiesis aka Hematopoeisis: The
process through which formed elements
are produced.
 Starts
with stem cells colonizing bone marrow,
spleen, thymus, & liver tissue in the embryo.

Myeloid Hemopoiesis: Cell production
occurring in the red bone marrow after
infancy.
Hemopoiesis
Proginator Cells develop into
hemocytoblasts.
 Hemocytoblasts form the different cells of
the formed elements.
 Erythropoietin (EPO) hormone increases
the number of blasts that will turn into
RBCs.
 Thrombopoietin (TPO) increases the
formation of platelets.

White Blood Cells

Leukolcytes aka White Blood Cells
(WBCs): Blood elements responsible for
immune responses. Less than 1% of blood
volume. 2 categories:
 Granulocytes
 Agranulocytes
White Blood Cells

Granulocytes: Contain cytoplasmic ganules
(vesicles). Three types:
 Neutrophils
aka Polymorphonuclear Leukocytes
(PMN’s): Multilobed nuclei with antimicrobial agents;
Gather at infection sites to destroy bacteria through
phagocytosis.
 Eosinophils: Bilobed nuclei; destroy antigenantibody complexes, allergens, and inflammatory
chemicals by phagocytosis; release enzymes that
destroy parasitic worms.
 Basophils: Release histamine to dilate blood
vessels and heparin to act as an anticoagulant.
These allow WBCs to reach inflamed areas faster.
White Blood Cells

Agranulocytes: White blood cells with no
granules. Two varieties:
 Lymphocytes:



Rounded nuclei –
B Cells: Antibodies secreted by lymphocytes
T Cells: Destroy foreign bodies or cancerous cells.
Helper T Cells: Enhance the abilities of other immune cells.
 Natural
Killer (NK) Cells: White blood cells that kill
tumors and virus-infected cells as part of the immune
response.
 Monocytes: Largest cells that form macrophages (to
phagocytize foreign particles). Also activate other
immune cells.
White Blood Cells
Differential White Blood Cell Count
(Differential WBC Count): A calculation
of the total number of each kind of WBC in
the blood stream.
 Average adult has a WBC of 5,000-10,000
cells per cubic millimeter.

Leukopoiesis

Leukopoiesis: The production of white
blood cells.
 Hemocytoblasts
differentiated into either…
B progenitors:
 T progenitors:
 Granulocyte macrophage colony-forming units

 Granulocytes
& monocytes are stored in
red bone marrow until needed.
 Lymphocytes are stored in lymphoid tissue
until mature & needed.
Platelets

Platelets: Cell fragments!
 Cell
membranes
 Pseudopods that allow for motion
 Vesicles
 No nucleus
 Phagocytic!
 10 day life-cycle
Hemostasis


Hemostasis: The process of stopping bleeding
& preventing blood loss from wounds. Mainly
occurs through platelets!
5 steps:
 Platelets
secrete growth factors to stimulate
fibroblast cell division & close the wound.
 Platelets secrete chemicals to attract white blood
cells.
 Platelets dissolve blood clots that are no longer
needed.
 Platelets secrete vasoconstrictors which cause
vascular spasms to prevent bleeding.
 Platelets form a platelet plug with their pseudopods
adhering to the vessel walls & drawing them together.
Hemostasis

Coagulation: The conversion of a soluble
fibrinogen into an insoluble fibrin.
 Fibrin net formed which stops the blood loss.
 Procoagulants: Clotting factors produced by the
liver
that trigger coagulation.
 HIGHLY dependent on Vitamin K for clot formation.

3 Steps of Coagulation:
 Clotting
factors go through enzyme reactions via
intrinsic or extrinsic pathways to form
prothrombinase (enzyme).
 Prothrombin activator causes prothrombinase to
turn prothrombin into thrombin.
 Thrombin converts fibrinogen to fibrin & forms a
clot.
Hemostasis
Clot Retraction: Tightening of the fibrin
clot that pulls the edges of the blood
vessel together so that the tissue may
repair.
 Fibrinolysis: The process of clot removal
after vessel repair.

Blood Types
Agglutinogens: Antigens on the surface
of the red blood cells that can react when
placed with blood of a different “type”.
 Two Groups of Blood Types based on
Agglutinogens:

 ABO
Group
 Rh Group
Blood Types

ABO Group: Based on Antigens A & B.


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Type A Blood: Antigen A present, Anti-B antibodies present
Type B Blood: Antigen B present, Anti-A antibodies present
Type O Blood: Neither antigen present, both antibodies present.



Type AB Blood: Both antigens present, neither antibodies
present.

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Most common blood type.
Universal Donor
Least common blood type.
Universal Receiver
Agglutinins: Antibodies that create an
antigen/antibody reaction (clotting) if blood types are
mixed.
Blood Types

Rh Group: Group based on one particular
agglutinogen (named after rhesus monkey).
 Rh-Positive:
Rh agglutinogens present on red blood
cells.

Approximately 90% of population
 Rh-Negative:

Rh agglutinogens not present.
Anti-Rh Antibodies: Formed during an initial
infusion of Rh+ blood into Rh- patient; leads to
hemolytic (anti-clotting) effect during future
encounters with Rh+.
Red Blood Cell Disorders

Polycythemia: Excessive levels of RBCs.
Causes…
 Hypertension
 Thrombosis
 Hemhorrage
Primary Polycythemia: Typically caused
by cancerous tissue.
 Secondary Polycythemia: Typically
caused by hypoxia (lack of oxygen).

Red Blood Cell Disorders

Anemia: Reduction of blood’s capacity to carry oxygen.

Iron-deficiency Anemia: Caused by a low level of iron, which is
necessary for oxygen bonding.


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More common in women than men; most common type.
Pernicious Anemia: Insufficient hemopoeisis caused by lack of
intrinsic factor.
Hemorrhagic Anemia: Caused by excessive RBC loss –
typically trauma or ulcers.
Hemolytic Anemia: Caused by RBCs rupturing prematurely.
Thalassemia: Deficiency in hemoglobin production.
Aplastic Anemia: Due to destruction of red boon marrow
caused by toxins, Gamma radiation, or medications needed for
hemopoises.
Red Blood Cell Disorders

Sickle-Cell Disease: Occurs when RBCs
are sickle-shaped due to presence of Hb-S
hemoglobin.
 Sickle
shape causes blocking of blood
vessels which causes pain & fatigue./
 Primarily found in Asia & Africa
 Genetically linked
White Blood Cell Disorders

Leukocytosis: High WBC count.
 Can
be a sign of allergy, infection, or
dehydration.

Leukopenia: Low WBC count.
 Can
be a sign of toxic chemicals, drug use, or
certain diseases.
White Blood Cell Disorders

Leukemia: Cancer of the blood-forming
tissues. Death typically occurs from
infection or excessive bleeding.
 Acute
Leukemia: Uncontrolled production of
immature leukocytes occurs.
 Chronic Leukemia: Accumulation of mature
leukoctyes due to leukocytes not dying at the
end of the normal cycle.
Platelet Disorders

Hemophilia: Clotting deficiency – typically
X-linked inherited.
 Hemophilia
A: Caused by a lack of factor VIII
that is necessary for coagulation. Most
common type.
 Hemophilia B: Caused by a lack of factor IX.
Platelet Disorders
Thrombus: An unwanted blood clot.
 Embolus: An unwanted blood clot that is
wandering throughout the blood vessels.
 Pulmonary Embolism: Blood clot in the
lungs.
 Anticoagulants: Thrombolytic agents that
can be used to reduce the possibility of
clotting.

 Ex.
Asprin, Willow bark, heparin, etc.
Blood Type Disorders
Hemolytic Disease of the Newborn
(HDN): Occurs when Rh negative mother
is exposed to Anti-Rh
blood
from an Rh positive
Gamma Globulin
fetus, causing severe anemia in the infant.
 Anti-Rh Gamma Globulin (RhoGAM):
Injected antibodies that can be given to
prevent HDN.
