Lecture #5: Blood & Circulation

Question 1

what are the two main components of blood?

Answer 1

1. Plasma (55%)
2. Cellular portion (formed elements- 45%)

Question 2

what is plasma composed of?

Answer 2

• water (92%)
• other substances (8%) organic molecules (metabolites, antibodies, enzymes and hormones) and inorganic matter (ex: Na+)

Question 3

what makes up the cellular portion of the blood?

Answer 3

• erythrocytes (RBCs)
• platelets (thrombocytes)
• leukocytes (WBCs)

Question 4

what are some characteristics of erythrocytes?

Answer 4

• transport O2 and CO2
• non nucleated
• flattened and biconcave
• stay circulating for 3-4 months
• made of hemoglobin (globin + iron)

Question 5

what are some characteristics of platelets?

Answer 5

• important for blood clotting
• non nucleated fragments
• made from large bone marrow cells (megakaryocytes)
• stay circulating for 5-9 days

Question 6

what are some characteristics of leukocytes?

Answer 6

• important for body defense
• nucleated and have amoeboid ability (can squeeze thru pores of the capillary wall to get to the site of infections)
• classified by staining appearance

Question 7

what is diapedesis?

Answer 7

the movement of leukocytes through pores of the capillary wall to get to the site of infections

Question 8

leukocytes are broken into two groups classified based on their staining appearance. what are the two groups and what defines them?

Answer 8

1. Granulocytes: contain cytoplasm granules & have a short life span
2. Agranulocytes: without cytoplasm granules & have a longer lifespan (months sometimes years)

Question 9

give examples of granulocytes.

Answer 9

• Neutrophils
• Eosinophils (acidophils)
• Basophils

Question 10

give examples of Agranulocytes.

Answer 10

• monocytes (macrophage- lifespan=months)
• limphocytes (mononuclear, responsible for humoral and cellular immunity- long lifespan= years)

Question 11

where do all blood cells originate from?

Answer 11

Hematopoetic stem cell within the bone marrow

Question 12

what do hematopoetic stem cells become?

Answer 12

multipotential stem cells (give rise to lymphoid progenitor cell and NK and T &B lymphocytes) and then myeloid progenitor cells (gives rise to neutrophil, basophil, eosinophil, monocyte macrophage, megakaryocytes, and RBCs)

Question 13

how is blood volume estimated? give some examples of blood volume

Answer 13

blood volume is estimated in percentage of the body weight

Dog= 7.2% Cattle= 7.7% Sheep= 8.0% Horses= 9.7%

Question 14

what are some disorders of the blood flow?

Answer 14

• hyperemia
• hemorrhage
• thrombosis
• embolism
• infarction
• edema
• shock

Question 15

what is hyperemia?

Answer 15

increased amount of blood in tissue or organ which results in distension of blood vessels

Question 16

what is hemorrhage?

Answer 16

escape of blood from the blood vessels

Question 17

what is edema?

Answer 17

abnormal accumulation of fluid in interstitial spaces of tissues

Question 18

what is ischemia?

Answer 18

local deficit of blood in tissues (restriction in blood supply)

Question 19

what is infarction?

Answer 19

local area of ischemic necrosis in a tissue caused by occlusion of the arterial supply of venous drainage (most infarcts result from thrombosis or embolism)

Question 20

what is thrombus?

Answer 20

an antemortem clot formed by blood coagulation that remains at the point of its formation (usually attached to the blood vessels wall or to valves of the heart)

Question 21

what is embolism?

Answer 21

a sudden blockage of an artery or vein by an obstruction that has arrived in the bloodstream

Question 22

what are the types of hymeremia?

Answer 22

physiological hyperemia or pathological hyperemia or Active hyperemia or passive hyperemia

Question 23

what is an example of physiological hyperemia?

Answer 23

• stomach and intestine during digestion
• muscles during exercise

Question 24

what is an example of pathological hyperemia?

Answer 24

• manifestation of a pathological process (not the cause)
• can be acute or chronic and local or generalized

Question 25

what is active hyperemia?

Answer 25

augmented flow of blood to tissues (arteriole-mediated engorgement of the vascular bed) ex: exercise, inflammation

Question 26

what is passive hyperemia or congestion ?

Answer 26

impaired outflow of blood (venous engorgement) can cause cardiac failure (valvular lesion)

Right valves= liver congestion

Left valves= lungs congestion

Question 27

what is hemorrhage what types are there??

Answer 27

• escape of blood from the cardiovascular system (bleeding)
• types of hemorrhage:
  
  • cardiac, aortic, arterial, capillary, venous
  • external -internal: filling of body cavities, hematoma (blood within a tissue or organ), formation (traumas, injections)

Question 28

what are some terms for blood appearing in abnormal locations?

Answer 28

• Hemoptysis= respiratory tract
• Epistaxis= bleeding from nose
• Hematemesis= vomiting of blood
• Melena= feces containing blood
• Hematuria= blood in urine
• Metorrhagia= uterovaginal bleeding
• Hemarthrosis= blood in joints
• Hemopericardium, Hemothorax, Hemoperitoneum = blood in cavities

Question 29

what do we call hemorrhages on surfaces (skin, mucous membranes, serosal)?

Answer 29

• Petechial (petechiae): small (1-2mm) hemorrhage foci (pinpoint)
• Purpura: larger than petechiae (>3mm)
• Ecchymotic (ecchymoses): larger diffuse (>1cm) and irregular areas of hemorrhage (blood splash)

Question 30

what are some causes of hemorrhage?

Answer 30

• trauma (non specific)
• septicemic, viremic and toxemic conditions (widespread petechiae and ecchymoses)
• disorders of coagulation: vit K, deficiency, liver diseases
• dicoumarol (dicoumarin): cattle fed with sweet clover
• competitive inhibition of Vit. K
• Warfarin (rat poison): competitive inhibition of Vit.K
• hemophilia and thrombocytopenia

Question 31

outcome of hemorrhage depends on what 3 factors?

Answer 31

1. location (critical in the CNS or heart)
2. volume (20-40% hemorrhagic shock)
3. Rate (chronic loss of small amount can be compensated- hematopoiesis)