L11-12 Circulatory Disturbances (Exam 2) Flashcards
1
Q
Circulatory System
A
Blood, heart, arterial, venous, microcirculation, lymphatics
“The circulatory system consist of blood, a central pump (the heart), blood distribution (arterial) and collection (venous) networks, and a system for exchange of nutrient and waste products between blood and extravascular tissue (microcirculation)”.
“ A network of vessels (lymphatics) that parallel the veins also contribute to circulation by draining fluid from the
extravascular spaces into the blood vascular system”.
2
Q
Microcirculation
A
a system for exchange of nutrient and waste products between blood and extravascular tissue
All the metabolic exchange between the blood and tissues happens at this level (microcirculation) (in capillary beds)
3
Q
Lymphatics
A
A network of vessels that parallel the veins also contribute to circulation by draining fluid from the
extravascular spaces into the blood vascular system
4
Q
The function of the blood is:
A
to carry oxygen, nutrients and waste products that are generated in the normal metabolism
5
Q
Arteries
A
Carry the blood to the tissues
6
Q
Veins
A
Are blood vessels that carry blood toward the heart.
7
Q
The main difference between arteries and veins:
A
Arteries: The bigger arteries contain elastic fibers/lamminae within the tunica media. Also in arteries the tunica media is the thicker of the tunics
Veins: the tunica externa is the thicker layer in veins; also veins have values (not seen in arteries)
8
Q
Capillaries
A
(small thin-walled vessel) Where metabolic exchange occurs
9
Q
The right heart propels unoxygenated blood through the pulmonary circulation, and the left heart propels oxygenated blood through the systemic circulation.
True or False ?
A
True
10
Q
Describe the basic circulation of blood after birth:
A
Poorly oxygenated blood will return to the right-side of the heart through the caudal/cranial vena cava into the right atrium -> RV -> Lungs to get oxygenated and it will come back through the pulmonary veins (carry oxygenated blood) -> LA -> LV -> Aorta -> tissues of the body
11
Q
In the arteries the Blood Pressure is going to be higher than in the veins
True or False ?
A
True
12
Q
The velocity of blood is higher in the arteries than the veins (little slower) and capillaries (lowest)
True or False ?
A
True
13
Q
Once again describe the basic circulation of blood flow ( 7 steps)
A
- The arterial blood is pumped through the left ventricle into the aorta.
- will go to the systemic circulation
- comes back through the veins cranial/caudal vena cava
- go into right ventricle
- pumped to the pulmonary artery into the pulmonary circulation
- into the lungs to get oxygenated
- and will come back through the pulmonary veins into the left atrium
14
Q
Arterioles
A
small arteries proximal to a capillary bed
15
Q
Metarterioles
A
arterial capillaries
16
Q
Capillaries
A
thin, semipermeable vessels that connect arterioles and venules
17
Q
Postcapillary venules
A
small vessels that merge to form veins after collecting
blood from a capillary network
18
Q
Smooth muscle of the arterioles and metarterioles regulates flow of blood into the capillary bed.
True or False ?
A
True
19
Q
There is a dramatic drop in pressure and blood
flow rate from the arterial to the venous side of
the microcirculation, facilitating interactions
between capillary blood and interstitial fluid.
True or False ?
A
True
20
Q
Microcirculation consists of:
A
Arterioles; Metarterioles; Capillaries; Postcapillary venules
21
Q
There is no net loss of fluid within the microciruculation
True or False ?
A
True
22
Q
Vascular Endothelium
A
The epithelial lining inside the blood vessels; Simple squamous epithelium
23
Q
Endothelium is both a physical barrier between intravascular and extravascular spaces, and it is
an important mediator of fluid distribution, hemostasis,
inflammation, and healing.
A
Vascular Endothelium
24
Q
Arrest bleeding by the physiological properties of vasoconstriction and coagulation or by surgical means.
A
Hemostasis
25
What are the three major roles of vascular endothelium ?
1. Role in hemostasis
2. Modulates perfusion:
3. Role in inflammation:
26
Most of the water in the body is located within cells
True or False ?
True
Intracellular Fluid (40%)
27
Homeostasis
“A tendency to stability in the normal body states”
28
Transcellular Fluid
~ about 5%
within body cavities ex. peritoneal cavity (normally has small amounts of fluid), pleural cavity, fluid in the joints
29
Plasma
~ about 4-5%
fluid in the blood
30
Interstitial Fluid
~ about 15%
in the extravascular space; in the interstitum
31
Interstitium
Space between tissue compartments (microcirculation and the cells).
Is the medium through which all metabolic products must pass between the microcirculation and the cells.
Composed of the Extracellular Matrix (ECM) and supporting cells
The place where you have the metabolic exchange between the blood and the tissues
32
Extracellular Matrix
Composed of structural molecules (collagen, reticulin, elastic fibers) and ground substance (glycoproteins like fibronectin & laminin, plus glycosaminoglycans, proteoglycans etc..)
33
Water distribution between plasma & the interstitium
| is primarily determined by:
the hydrostatic & osmotic
| pressures differences between the 2 compartments
34
Starling forces
the movement of fluid across capillary membranes vua hydrostatic and osmotic pressures
35
Most water leakage occurs in capillaries or post- capillary venules, which have a semi-permeable membrane wall that allows water to move more freely than proteins.
True or False ?
True
36
The hydrostatic pressure moves fluid into of the vasculature; the osmotic pressure of plasma proteins (oncotic pressure) moves fluid out of the vasculature.
True or False ?
False
Note: the hydrostatic pressure moves fluid OUT of the vasculature; the osmotic pressure of plasma proteins (oncotic pressure) moves fluid INTO the vasculature.
37
Increased hydrostatic pressure or diminished plasma
osmotic pressure will cause extravascular fluid to accumulate. Tissue lymphatics remove much of the excess volume, eventually returning it to the circulation via the thoracic duct; however, if the capacity for lymphatic drainage is exceeded, tissue edema results.
True or False ?
True
38
Edema
abnormal increase in the amount of fluid that remains in the interstitum
39
What are the 4 Pathomechanisms of Edema ?
1. Increased blood hydrostatic pressure
2. Decreased plasma colloidal osmotic (a.k.a.
oncotic) pressure
3. Lymphatic obstruction
4. Increased vascular permeability (inflammation)
40
Inflammatory Edema
Increased vascular permeability – refers as an
“exudate”
Edema fluid in these cases is “protein rich” an exudate
(high protein content (>30g/L), specific gravity (>1.025), total nucleated cells (
41
Non-inflammatory Edema
refers to as a “transudate”
Edema fluid in these cases is “protein poor” low protein content (
42
Pericardial effusion
Pneumonia
Hyperemia
Examples of Inflammatory edema
43
edema of CHF
edema of liver failure
renal failure
Examples of non-inflammatory edema
44
Gross appearance of edema (name 5)
1. Wet
2. Gelatinous and heavy
3. Swollen organs
4. Fluid weeps from cut surfaces
5. May be yellow-ish
45
Histological appearance of edema (Name 5)
1. Clear or pale eosinophilic staining depending on whether is non-inflammatory or inflammatory edema. [Inflammatory edema will pick up the eosin
stain - stain more pinkish]
2. Spaces are distended
3. Blood vessels may be filled with red blood cells
4. Lymphatics are dilated [they will be draining all
the fluid that was
accumulated]
5. Collagen bundles are separated
46
Pitting edema
When pressure is applied to an area of edema a depression or dent results as excessive interstitial
fluid is forced to adjacent areas
Ex. Horse with right-sided CHF; when you press it it will leave an
indentation -> subcutaneous edema
47
Fluid in the thoracic cavity
Hydrothorax
48
Pericardial effusion
Accumulation of fluid within the pericardial sac
Ex. “mulberry heart disease”- (inflammatory
edema).
49
Fluid (transudate) within the peritoneal cavity.
Ascites or hydroperitoneum
50
Anasarca
Generalized edema with profuse accumulation of fluid
within the subcutaneous tissue.
Note: Generally associated with more severe
cardiac anomalies
51
Swelling in mandibular space
Submandibular edema (“bottle jaw”)
Note: Commonly associated with severe GI parasitism
and hypoproteinemia in sheep. Can be associated with CHF but mostly
associated with severe GI Parasitism. Primarily in ruminants and sheep;
hymoncous contortus
52
Hyperemia and Congestion
Both terms indicate a local increase in blood volume and flow within the vascular bed.
53
Hyperemia
indicates increase of arteriole-mediated engorgement of the vascular bed. Blood is oxygenated
54
Congestion
indicates passive, venous engorgement. Blood is not oxygenated. {Passive engorgement of vascular
beds caused by a decreased outflow of blood}
55
Physiological Hyperemia (normal)
Digestion: ↑ blood flow to the GI tract during digestion.
Exercise: ↑ blood flow to muscles during exercise
To dissipate heat: ↑blood flow to the skin to dissipate heat and cool down.
Neurovascular: Involuntary ↑in blood flow to the face (facial hyperemia) as a result of embarrassment or emotional distress
common in people with social anxiety.
56
Pathological Hyperemia (abnormal)
Caused by an underlying pathological process – usually inflammation.
Arteriolar dilatation occurs secondary to inflammatory stimuli (inflammatory mediators).
Reddening (“rubor”) is one of the cardinal signs of inflammation (tumor, calor, rubor, pain, loss of function).
Often associated with edema
57
Gingivitis
inflammation of the gums
; Pathological Hyperemia
58
Bulbar and palpebral Conjunctivitis
inflammatory condition of the membrane that lines the eyelids and covers the exposed surface of the sclera; Pathological Hyperemia
59
Congestion will result in increased hydrostatic pressure within the veins -> this can lead to edema
True or False ?
True
60
Name this:
Twisting of vessels obstructs gastric veins → severe venous congestion (acute, local, congestion) → ischemia (necrosis) →loss of endothelial integrity →hemorrhage →shock→death
Gastric volvulus (torsion)
Ex. of localized congestion
61
Very often the small intestine will twist along its axis
Intestinal volvulus
Ex. of localized congestion
{Impaired venous return; leads to congestion, hypoxia, venous infarction with necrosis}
62
Pulmonary congestion: Usually the result of
heart failure and associated with edema.
True or False ?
True
63
SUBACUTE TO CHRONIC HEPATIC CONGESTION IS USUALLY THE RESULT OF RIGHT-SIDED CHF
True or False ?
True
64
“Nutmeg liver” is an example of Chronic hepatic congestion
True or False ?
True
65
The hepatocytes in zone 1 of the hepatic lobule are
more resistant
to hypoxia
True or False ?
True
66
The Portal triad containins:
bile duct, portal
vein and hepatic artery
67
The central vein: Drains the caudal
vena cava and is close to zone 3
True or False ?
True
68
Zone 3 is more susceptible to hypoxia bc most of the O2 is already gone.
True or False ?
True
69
Unoxygenated blood in the liver is
going to come through the hepatic
artery (located in the portal triads)
True or False ?
False
Note: Oxygenated blood in the liver is
going to come through the hepatic
artery (located in the portal triads)
70
What are the 7 categories of Circulatory Disturbances ?
1. Edema
2. Hyperemia & Congestion
3. Hemorrhage
4. Hemostasis
5. Thrombosis, Embolism & DIC
6. Infarction
7. Shock
71
Siderophages
macrophages
with hemosiderin in the middle;
macrophages containing pigment
72
Endothelial cells produce molecules that have a(n):
Anti-thrombotic & pro-fibrinolytic in the normal state
AND
Pro-thrombotic and anti-fibrinolytic during injury
73
Pro-inflammatory cytokines produced by vascular endothelium cells:
will make blood vessels more leaky so plasma and proteins can go into this area in order to facilitate healing and repair. RBCS can go in and supply oxygen to the neutrophils and macrophages trying to repair damage
74
Clinical significance of edema is dependent upon:
extent, location and duration
75
Hepatic toxins will be very close to the portal circulation; so hepatocytes close to the portal triad will get damaged first
True or False ?
True
76
Hemorrhage
Is defined as the escape of blood from the blood vessels (extravasation)
Can be external or internal (within tissues or body
cavities)
77
Name 4 causes of hemorrhage
1. Trauma
2. Sepsis, viremia, bacteremia or toxic conditions
3. Abdominal neoplasia may lead to hemoperitoneum
4. Coagulation abnormalities (platelet and coagulation factor defects or deficiencies)
78
Profuse blood loss is the most common cause of
hypovolemic shock; Hemorrhage in the brain or
heart can be fatal.
True or False ?
True
79
Hemopericardium
Bleeding into the pericardial sac
leads to fatal cardiac tamponade. If this kind of hemorrage occurs acutely this can lead to death
80
Rhexis
tear in the vascular wall (or heart). (Can cause hemorrhage)
81
Dissecting aneurysm
an excessive localized enlargement of an artery caused by a weakening of the artery wall.
Ex. Copper deficiency (maintains the health of the vascular wall)
82
Hemorrhage due to a small defect in the vessel wall or rbc‟s passing through the vessel wall in cases of inflammation or congestion (like in the lungs of
animals with left-sided CHF…)
Diapedesis
Vascular wall becomes leaky; Tight junctions will separate a little bit and the cells will squeeze out
83
Hemorrhagic diathesis
Increased tendency to hemorrhage from usually
insignificant injuries (seen in a wide variety of clotting
disorders).
Ex. Animals with inherited clotting disorders
84
Hemothorax
blood in the thoracic cavity
85
Hemoperitoneum
blood in the peritoneal cavity
86
Hemarthrosis
blood within a joint space
87
Hemoptysis
Coughing up of blood or bloodstained sputum from the lungs or airways.
88
Epistaxis
Bleeding from the nose.
Ex. From mycotic infections in the gutteral pouch of horses
89
Petechia (pl. petechiae)
Very tiny hemorrage; associated with spesis. up to 1-2 mm in size. Especially found on skin, mucosal and serosal surfaces
90
Ecchymosis (pl, ecchymoses)
Larger than petechia (up to ~1 or 2 cm). As seen in bruise (contusion) or small hematoma. When the hemorrage is still focal but bigger; basically large petechia
91
Agonal Hemorrhages
Petechiae and ecchymoses associated with terminal hypoxia.
Often seen along the coronary groove in the heart of animals and also in the endocardial surface. Very often can indicate sepsis or hypoxia
92
Suffusive hemorrhage
larger than ecchymosis and contiguous. Multifocal to coalesing
93
Paint-brush hemorrhage
Looks like if red paint was hastily applied with a paint brush. Most common on mucosal and serosal surfaces.
94
Central mass of fibrin & red blood cells
surrounded by supportive vascular connective tissue
macrophages will eventually phagocytize this lesion.
Organizing hematoma (A hemorrhage resolution)
95
This process is a hemotoma resolution
Hemoglobin (dark red blue color) enzymatically converted to bilirubin (blue-green color) and
eventually into hemosiderin (gold-brown color).
True or False ?
True
96
Normal hemostasis is a physiological response to
vascular damage Provides a mechanism to seal an
injured vessel to prevent blood loss.
True or False
True
Hemostasis is something that is good - it is a physiological process that helps to repair an area of vascular damage
97
The pathological form of hemostasis is ____________
thrombosis
Thrombosis is a pathological process; hemostasis is normal
98
Thrombosis:
a clot (thrombus) forms within a vessel which is not injured or only mildly injured.
Thrombosis can be viewed as an inappropriate activation of the normal hemostatic process
Aggregate of platelets, fibrin and entrapped blood cells.
Can result in occlusion of the vascular lumen and embolism
It is adhered to the vascular wall as opposite to a blood clot.
99
Virchow triad:
describes the three broad categories of factors that are thought to contribute to thrombosis
1. Endothelial injury (more important factor)
2. Alterations in blood flow (turbulence or stasis)
3. Hypercoagulability
↑in coagulation factors (or ↑sensitivity to)
↓ in coagulation inhibitors
All of these play a significant role in the formation of a thrombosis
100
Pulmonary thrombosis
Seen in dogs with severe renal glomerular
disease -> protein losing nephropathy -> Significant loss of
Antithrombin III, a major inhibitor of thrombin
101
Verminous thrombosis
Cause by vermin infection
Ex. thrombus formation in the cranial mesenteric artery of horses with Strongylus vulgaris infection
102
FATE (Feline Aortic Thromboembolism, or Saddle Thrombus)
Happens in cats
The split where the aorta becomes the left and right iliac arteries is called the saddle.
A saddle thrombus is a blood clot that breaks off from a larger blood clot in the heart, travels down the aorta and lodges at the saddle.
Acute onset of paralysis
103
If pieces of a thrombus break off from the
original mass and sail downstream to lodge at
a distant site, that process is called ________
Embolism
Embolism is the passage through the venous or the arterial circulation of any material capable of lodging in a blood vessel lumen
104
Embolus
The mass that brakes off
“An embolus is any detached intravascular mass (solid, liquid or gaseous) which is carried by the blood to a site distal to the point of origin; most emboli originate from detached pieces of a thrombus, hence the commonly used term of thromboembolism”.
water divers can develop this compression embolism; so have to go up very slowly to prevent this
105
In cattle it is not uncommon to see vena cava thrombosis (Thrombis of the veins)- ruminal acidosis - multiple pulmonary abcessation and they can die from that.
True or False ?
True
106
Fat embolism
Could be a complication of long bone fractures
Ex. of fat embolism due to CPR
Fractures of bone can result in trauma; fat can get into
systemic system and produce pulmonary embolism and infarction
107
Infectious causes of thrombosis/ thromboembolism
Bacterial valvular endocarditis in cattle
often involve the right AV valve and can
give rise to septic emboli that will lodge in the
pulmonary arteries inflammation/ abscess
Formation (embolic pneumonia).
108
Thrombotic Meningoencephalitis (TME)
Associated with hemorrhage and inflammation
Etiology: Histophilus somni infection – results in vasculitis and thrombosis; bacteria in cattle that has the ability to produce vascular endocarditis
109
Disseminated Intravascular Coagulation (DIC)
“Potentially catastrophic systemic reaction (thrombo-hemorrhagic disorder) in which there is generalized activation of the blood coagulation system."
Signs of tissue hypoxia, infarction or/and hemorrhage are seen.
110
Infarction
Localized area of ischemic necrosis in a tissue or organ caused by occlusion of either the arterial supply or the venous drainage
111
Venous infarcts are usually intensely hemorrhagic as blood backs up into the affected tissue behind
the obstruction
True or False ?
True
112
Arterial infarcts are often initially hemorrhagic
but become pale as the area of coagulation
necrosis becomes evident
True or False ?
True
113
Microscopically an infarct is a focal area of
coagulation necrosis
True or False ?
True
114
Shock (Cardiac collapse)
Shock is the final common pathway for a number of
potentially lethal clinical events.
shock gives rise to systemic hypoperfusion; it can be caused either by reduced cardiac output or by reduced effective circulating blood volume.
End Result: hypotension, impaired tissue perfusion, and
cellular hypoxia.
115
Types of Shock:
1. Cardiogenic shock
2. Hypovolemic Shock
3. Blood Maldistribution
- Anaphylactic (Type 1 hypersensitivity)
- Neurogenic
- Septic
116
Cardiogenic shock
failure of the heart to maintain normal cardiac output
117
Hypovolemic Shock
Fluid loss due to hemorrhage, vomiting, diarrhea
118
Most cases of septic shock are caused by endotoxin-producing gram-negative bacilli (endotoxic shock)
T or F
True
Endotoxins are bacterial wall lipopolysaccharides (LPS) consisting of a toxic fatty acid (lipid A) core common to all gram-negative bacteria, and a complex polysaccharide coat (including O antigen) unique for each species. LPS and other microbial substances induce injury & activation of the vascular endothelium plus stimulate (“activate”) WBCs to release cytokines vasodilation & pro-thrombotic diathesis (DIC).
