Unit 1.3-1.4 Flashcards
the accumulation of abnormal quantities of water in the tissues or body cavities
edema
What are the gross classifications of edema (6)?
swollen, pits on pressure, cool to touch, not reddened, no pain, distended lymphatics
initiated by endothelial damage and accomplished by vasoconstriction and formation of a platelet plug
primary hemostasis
What two things initiate vasoconstriction?
neurogenic and chemical mediators
What is the first line of defense against accidental blood loss?
platelets
How long do platelets live?
5-10 days
contractile protein inside platelets that functions for clot retraction:
thrombosthenin
What initiates secondary hemostasis?
when the platelet plug is insufficient to stop hemorrhage
What is the end product of secondary hemostasis?
fibrin
Where are most coagulation factors synthesized?
liver
Which coagulation factors require cofactor Vitamin K for post synthetic modification so that they can bind calcium?
10, 9, 7, 2
What is the first coagulation factor in the common pathways?
Xa
most important inactivator of thrombin and is much more potent when bound to heparin or endothelial cells:
antithrombin III
What determines the effectiveness of vasoconstriction?
size of vessel, amount of smooth muscle in the vessel wall
What drug is sometimes referred to as COX inhibitors?
NSAIDS
What body process is cyclooxygenase involved in?
inflammation
What happens when the substances released from platelets are released inappropriately in the arteries?
artherosclerotic lesions
Which protein within the platelets enables clot contraction and consolidation and requires ATP to work?
thrombosthenin
Abnormalities in vascular permeability or hemostasis can result in injury, even…
with an intact blood supply
What are the three things that normal fluid homeostasis encompasses?
- maintenance of vessel wall integrity
- intravascular pressure
- osmolarity (within certain physiological ranges)
What three things can affect the net movement of water across the vascular wall?
changes in vascular volume, pressure, or protein content
What percentage of lean body weight it water?
60%
How much body weight is intracellular? Extra? Plasma?
66%, 25%, 8%
What are the three common locations to see edema?
SQ, brain, lungs (but may occur in any tissue)
Microscopically manifests only as subtle cell swelling, with clearing and separation of the intracellular matrix elements
edema
fluid in pleural cavity
hydrothorax
fluid in pericardial sac
hydropericardium
fluid in uterine tube
hydrosalpinx
accumulation of fluid in the brain
hydrocephalus
fluid-filled cyst anywhere in the body
hydrocoele
edema in the peritoneal cavity
ascites (hydroperitoneum)
severe and generalized edema, with profound SQ tissue swelling
anasarca
What are two causes of intracellular edema?
- depression of metabolic systems of the tissues or lack of adequate nutrition to cells
- inflammation
What is the three causes of extracellular edema?
- abnormal leakage of fluid from blood capillaries
- failure of lymphatic system
- renal retention of salt and water
Fluid accumulation due to hydrostatic imbalances between IV and EV compartments DESPITE normal vascular permeability; clear, colorless, or slightly yellow
transudate (non-inflammatory edema)
Related to increased endothelial permeability -caused by leakage of plasma proteins (mainly albumin) and leukocytes; usually opaque
exudate (inflammatory edema)
Common locations of generalized edema in horses:
ventral abdomen/thorax, distal extremities (if severe)
Common location of generalized edema in cats:
hydrothorax
Common locations of generalized edema in cows:
intermandibular space, brisket area (thoracic inlet)
Common location of generalized edema in dogs:
ascites (abd. cavity)
How can bacteria cause edema?
toxins released by bacteria can cause vascular leakage of proteins
2 common features of the micro-appearance of edema:
- separation of tissues by spaces that are clear or pink
2. dilation of lymphatic vessels
increased intravascular pressure causes…
transudate
decreased plasma colloid osmotic pressure (proteins in blood stream, sucking water into vessels) causes….
transudate
increased vascular permeability causes…
transudate (this is NOT inflammation)
lymphatic obstruction causes…
exudate
What two common organs can fail and cause edema?
kidneys, heart
Which two Starling’s forces are typically balanced so that there is no net gain or loss of fluid across the capillary bed?
- capillary hydrostatic pressure
2. osmotic forces
Which two functions of Starling’s forces can lead to extravascular fluid (edema)?
- increased hydrostratic pressure
2. decreased plasma oncotic pressure
What path does the lymphatics take to remove excess extravascular volume?
returns to circulation via the thoracic duct
What is the hydrostatic pressure in mm Hg at the arterial end of the capillary?
37
What is the hydrostatic pressure in mm Hg at the venous end of the capillary?
17
Three main diseases that can cause increased hydrostatic pressure, resulting in impaired venous return and congestion:
congestive heart failure, cirrhosis of the liver, obstruction of the narrowing veins
As a result of hypoproteinemia, fluid and sodium are not reabsorbed at the venous end of the capillary are so…
fluid is accumulated in the interstitium as edema
List the five main diseases the can cause decreased oncotic pressure of the plasma (hypoproteinemia)
kidney disease, cirrhosis of the liver/liver failure, malnutrtion, protein-losing gastroenteropathies, GI parasitism
List some of the main diseases that cause lymphatic obstruction (4):
inflammation, neoplasia (spreads/metastasizes), post-surgical, post-irradiation
2 responsible diseases/conditions that cause sodium retention, resulting in increased plasma volume:
heart failure, kidney disease
released from the juxtaglomerular appartus:
renin
causes secretion of aldosterone:
angiotensin
causes increased absorption of Na in the kidneys
aldosterone
Heart failure leads to…
hypOperfusion of the kidneys
What are the two effects of kidney disease?
Na not excreted, results in Na retention
an active process resulting in increased tissue blood flow due to arteriolar dilation
active hyperemia
Why is the affected area of active hyperemia red?
because of engorgement with oxygenated blood
When are two common times to see active hyperemia?
- skeletal muscles during exercise
2. at sites of inflammation
a passive process resulting from impaired outflow from a tissue
congestion
What two things could cause interference with venous drainage?
heart failure (systemic), isolated venous obstruction (local)
Why does congestion have a red-blue coloration (cyanosis)?
accumulation of deoxygenated blood
What are three main causes of congestion?
heart failure, venous occlusion, hypostasis
What is most affected if the heart is left-sided heart failure?
lung most affected (chronic pulmonary congestion)
What is most affected in right-sided heart failure?
liver most affected (chronic passive congestion)
thrombus, pressure, twisting =
venous occlusion (localized)
Not moving around enough to get the blood flowing:
hypostasis
blood pooling in organs and tissues on the lower side of a recumbent animal; contrast to livor mortis
hypostatic congestion
Caused by any disease that results in right heart failure (RHF), usually of the liver
chronic passive congestion
caused by any disease that results in left heart failure, output mismatch
chronic pulmonary congestion
In active hyperemia, increased inflow leads to engorgement with oxygenated blood, resulting in:
erythema
In congestion, diminished outflow leads to a capillary bed swollen with deoxygenated venous blood and resulting in:
cyanosis
Effects of chronic congestion (4):
- anoxic injury (atrophy & fibrosis)
- thrombosis
- edema
- hemosiderin disposition
