Circulatory Disturbance Flashcards
The relationship between the various forces at work in the microcirculatory
bed is described by what is known as the
Starling Equilibrium
Mechanisms Of Edema
The mechanisms of edema include the following mechanisms:
1) Decreased plasma colloid osmotic pressure
2) Increased blood hydrostatic pressure
3) Increased vascular permeability
4) Lymphatic obstruction
Recall that plasma electrophoresis
separates the constituents of plasma to
albumin, alpha, beta, and gamma
globulins
is the most important plasma protein, and is principally
produced in the liver
Albumin
the obstruction and lymphatic channel damage is caused by parasites such as
filarial worms as observed in __________ in humans.
elephantiasis
Morphology Of Edema
➢ The changes associated with edema are dependent on:
• the severity of edema
• the rapidity of onset,
• the extent,
• the anatomic location, and
• the underlying cause of edema.
in the subcutaneous tissue takes the form of fluid
collections that may be tinged red with blood or other colors
depending on the underlying cause.
Edema
Edema fluid collects in the lowermost portions of the body such as the
ventral abdomen and the limbs as influenced by gravity in a pattern
referred as
dependent edema
When such edema is severe and generalized, it is possible to push a finger
against such edematous tissue and produce a dent. Such a change is
described as .
pitting edema
is recognized by excess clear fluid and is most easily visualized
beneath the skin or between the layers of mucous membranes or in
lobules of the lung, where there is space for accumulation to occur.
Edema
– generalized edema or extreme edema in the entire body, as
occurs in some aborted fetuses.
Anasarca
– common lesion affecting lungs and is often the
immediate cause of death in many different disease conditions (i.e.,
resultant of left congestive heart failure or LCHF).
Pulmonary edema
Edema is such a characteristic lesion in some specific diseases that it is
incorporated into the name of the disease:
▪ Gut edema caused by Escherichia coli in pigs
▪ Malignant edema caused by Clostridium septicumin in
several species
– fixative of choice to retain edema lesion
Bouin’s fluid or solution
Types of Edema
- Localized edema
- Generalized edema (as in anasarca)
In active process, edema is an:
Exudate
Exudate – an inflammatory effusion or edema characterized
by:
•
- high protein content
• increased specific gravity
• increased number of inflammatory cells
In passive process, edema is a:
Transudate
Transudate – a non-inflammatory effusion or edema
characterized by:
• Low protein content
• Low specific gravity
• Low or absence on inflammatory cells
The term _______ refers to a local increase in the volume of blood in
tissues due to dilation of the small blood vessels
hyperemia
refers to the
damming of blood in an area due to diminished venous outflow, and is considered
a form of passive hyperemia. Yet, the two are oftentimes used as synonyms
congestion
occurs following an increase in demand for more blood as in exercise,
Physiological
hyperemia
on the other hand occurs as a manifestation of some
alterations in blood flow characteristics. It is not however, the cause of the
alteration, rather, the result of some underlying pathological process. These
include those observed during inflammation, in cardiac failure, and obstructive
venous diseases.
Pathological hyperemia
Three factors are considered in the classification of pathological hyperemia, and
includes the following:
- Duration of hyperemia (acute or chronic)
- Extent of hyperemia (general or local)
- The underlying mechanism (active or passive)
Thrombosis is the formation of ante mortem clot within the blood vessels, and the
clot formed is called
thrombus
Hemostasis, or the arrest of hemorrhage by clot formation involves five
essential steps:
- vascular contraction,
- stasis of blood,
- endothelial adhesion,
- blood coagulation, and
- platelet aggregation.
that involves the components normally present in the plasma
intrinsic clotting
mechanism
that involves tissue component in
addition to the components from the blood.
extrinsic clotting mechanism
– the non-thrombogenic properties of intact
endothelial lining cells is due to the carbohydrate-rich cell coat (glycocalyx)
that prevents circulating cells from adhering to the surface.
Glycocalyx Theory
– the negatively-charged surface of
endothelial lining lead to a mutual electrostatic repulsion between two sets
of negatively charged cells (endothelia and blood cells).
Surface Negativity Theory
– Endothelial cells have the ability to
synthesize prostacyclin (PGI2)
Surveillance System Theory
Based on location:
Thrombi
o Cardiac thrombi
o Arterial thrombi
o Venous thrombi
o Lymphatic thrombi
o Capillary thrombi or hyaline thrombi
– attached to the endocardial wall of heart
Mural thrombi
– attached to the valves of the heart
Valvular thrombi
– blocks the entire lumen of the blood vessel
Occluding thrombi
– allows partial flow of blood
Canalized thrombi
– straddles the bifurcation of blood vessel
Saddle thrombi
– trailing thrombi with one end attached and
the other freely moving.
Obturating thrombi
– contains bacteria
Septic thrombi
– no pathogenic agent present
Aseptic thrombi
– contains parasites such as filarial worms
Parasitic thrombi
– composed of all blood cell components
Red thrombi
– composed of all blood cell components
Red thrombi
– composed entirely of platelets
Pale or white thrombi
– layered red and white thrombi
Laminated or mixed thrombi
are usually
pale gray-tan mass consisting of
nearly concentric layers of
alternating bands of fibrin and
platelets mixed with scanty amount
of coagulated red blood cells. T
Arterial thrombi
During propagation then, concentric laminations are formed which are called the
lines of Zahn.
When a solid mass is transported from one part of the body to another
through the circulatory system, the process is called _________, and the mass
called an _______ (plural: emboli).
embolism
embolus
– ischemia due to reduced flow of oxygenated blood as in hypovolemic shock
Stagnant Anoxia
– result from insufficient oxygenation of blood as may
occur in severe pneumonia
Anoxic Anoxia
– caused by low hemoglobin or reduced capacity of blood
to carry oxygen as in carbon monoxide poisoning
Anemic Anoxia
– the oxygenation of blood is normal, but the tissues
cannot utilize oxygen due to damage to certain critical cellular respiratory
processes such as that seen in cyanide poisoning
Histotoxic Anoxia
- is a localized anemia
- results to infarction (if lodges in organs with so called “end arteries”
- if partial or gradual, atrophy may result
Ischemia
An ______ is an area of coagulative necrosis caused by ischemia and is due to
obstruction of the blood supply following thrombosis or embolism. The process is
called ________.
infarct
infarction
The cells and tissues most susceptible to infarction are those biologically active
cells that include the:
▪ brain,
▪ renal tubular epithelia,
▪ heart muscles, and
▪ most parenchymal tissues.
_____ are resistant to infarction such that the
stromal support of infracted tissues survives while the parenchyma succumb to
infarction.
fibroblasts
single vessel) – the artery ramifies into smaller
branches as it ends. Organs supplied by this type of arterial tree include
the kidneys, heart muscles, brain and spleen, and are the organs where
infarction is commonly seen (Figure 3.6).
Functional End-Artery (
– there are separate blood supply that often has several
functional anastomotic channels. Organs supplied by this type include
Parallel System
are intensely hemorrhagic as blood backs up into the affected
tissue behind the obstruction
Venous infarcts
are generally pale, except in loose
tissues such as the lungs that tend to be hemorrhagic. Solid parenchymatous
organs like the heart and kidneys tend to have pale infarcts.
Arterial infarcts
– includes hemorrhage and traumatic shock. The
operating mechanism is that of inadequate blood or plasma volume.
Hypovolemic Shock
– shock resulting from myocardial infarction. The
failure of myocardial pump due to intrinsic myocardial damage
Cardiogenic Shock
– associated with toxemia and septicemia,
including endotoxemia (endotoxic shock). Endothelial cell injury causes
the initiation of disseminated intravascular coagulation.
Septic or Toxic Shock
– resulting from severe fright, pain and trauma without
hemorrhage.
Neurogenic Shock
– as a result of massive degranulation of mast cells
following antigen-antibody interaction
Anaphylactic Shock
