Circulatory Disorder: Hemorrhage & Homeostasis

Question 1

Describe hemorrhage.

Answer 1

-escape of blood from blood vessels (extravasation)
>ext or int (tissue/body cavity)
>arterial, venous, capillary
*hyperemia & congestion = blood in vessel

Question 2

Describe the 2 types of hemorrhage.

Answer 2

1. Rhexis
   -tear in vascular wall due to:
   >trauma, necrosis of blood vessel wall, invasion of blood vessel by neoplasia
2. Diapedesis
   -small defect in vessel wall or RBCs passing thru vessel wall in inflam or congestion due to:
   >inflam, congestion, hypoxia, toxins, coagulation disorder
   *wall is intact, but inc capillary permeability

Question 3

Describe the causes of hemorrhage.

Answer 3

1. Trauma
2. Sepsis, viremia, bacteremia, toxic conditions -> necrosis & degen of endothelial cells
3. Chemical agents
4. Neoplasia
5. Coagulation abnormalities

Question 4

Describe hemorrhage classification based on size.

Answer 4

1. Petechia = 1-2 mm
2. Purpura = 3mm-1cm
3. Ecchymosis = 1-2 cm
4. Suffusive = larger than ecchymosis
5. Paint brush
6. Hematoma
7. Linear
   *Diathesis = inc tendency to bleed/bruise easily from insig injuries (platelet & coagulation disorders)

Question 5

Describe hemorrhage classification based on location.

Answer 5

1. Perivascular
2. Sub-serosal
3. Sub-mucosal
4. Sub-capsular
5. Subdural
   -bleeding between arachnoid mater & dura
6. Epidural
   -bleeding between dura mater & skull
7. Hemothorax
   -blood in thoracic cavity
8. Hemopericardium
   -blood within pericardial sac
   -can lead to fatal cardiac tamponade
9. Hemoperitoneum
   -blood in peritoneal cavity

Question 6

Describe other areas of hemorrhage.

Answer 6

1. Hemarthrosis = blood in joint space
2. Hemopytsis = coughing up blood or blood stained sputum from lungs or airways
3. Hyphema = blood in anterior chamber of eye
4. Epistaxis = bleeding from nose
5. Hematemesis = vomit up blood
6. Hematochezia = fresh blood in stool
7. Melena = tarry blood in stool

Question 7

Describe hemorrhage resolution.

Answer 7

-result of hemostasis
-sm amount can be reabsorbed
-lg amount require phagocytosis & degradation by macrophage
-organizing hematoma = central mass of fibrin & RBCs surrounded by supportive vascular CT (fibrous) -> macs phagocytose lesion

Question 8

Describe hemorrhage clinical significance.

Answer 8

1. General (vol & rate) hemorrhagic shock
   -profuse blood loss -> acute anemia -> hypovolemic shock -> death
   -anemia bc repeated small hemorrhage
2. Location & severity compressive effects
   -mechanical compression of organs due to a hematoma
   -brain & heart = fatal

Question 9

Describe hemostasis.

Answer 9

-keeps blood fluid clot free in blood vessel
-physiological response to vascular damage = rapid clot formation
-mechanisms to seal an injured vessel to prevent blood loss

Question 10

Describe the mechanisms of hemostasis.

Answer 10

Question 11

Describe the coagulation cascade.

Answer 11

-enzymatic conversions
>each step proteolytically cleaves inactive proenzyme into activated enzyme = thrombin formation
-conclusion of proteolytic cascade = thrombin coverts soluble plasma protein fibrinogen into fibrin
-coagulation factors are plasma proteins made by liver

Question 12

Describe the end of the coagulation cascade.

Answer 12

1. Stabilize clot by fibrin
2. Contract fibrin platelet clot
3. Reduce size of clot (restore flow)
4. Draws damaged vessel edges closer (for healing)

Question 13

Describe why coagulation would fail.

Answer 13

1. Hepatic disease (cant make coagulation factors)
2. Platelet defect
3. Nutrition deficiency (vit K)
4. Toxics (warfarin)
5. Hemophilias (absence of coagulation factors)
6. Bacterial invasion during clot formation