Cardiovascular System, Lecture 1

Question 1

What are the two components to blood

Answer 1

~ 5 L of blood by volume forming 2 components:
plasma
cellular elements:
- erythrocytes - red blood cells
- leukocytes - white blood cells
- thrombocytes - platelets
(produced in red bone marrow, ~100 billion new cells/day)

Question 2

Plasma - plasma volume

Answer 2

water (92%) - fluid portion
plasma proteins (7%) - key component of osmotic pressure (solute concentration)
- by keeping plasma proteins in the plasma helps us establish osmotic pressure
- if there is uneven concentration, we can utilize osmotic pressure to balance it out
- semipermeable (some things can move through while others cannot)
- the fluid part (water) can move through not the solids
- solute cannot move through, so the water is moved through instead with the use of osmotic pressure as it is the driving force
other solutes (1%)
- electrolytes (sodium, potassium, chloride, etc.)
- nutrients (carbohydrates, fats, proteins, vitamins, minerals)
- wastes (urea, creatinine, bilirubin)
- gases (oxygen, CD)
- regulatory substances (hormones, enzymes)

Question 3

Fluid compartments

Answer 3

extracellular fluid: outside cells
- plasma: outside cells in blood
- interstitial fluid: outside cells in tissues
intracellular fluid: inside cells
can get exchanges between compartments (compartment shifts):
- intracellular <-> extracellular
- plasma <->interstitial
hydration status changes - plasma volume changes - compartment shifts
ex. if someone is dehydrated, try to shift fluid to get it to muscle cells where dehydration is
- intracellular fluid is 2/3
intracellular (biggest), interstitial fluid (middle), plasma (smallest)

Question 4

Leukocytes

Answer 4

formed in red bone marrow by leukopoiesis

Question 5

Thrombocytes

Answer 5

• formed in red bone narrow by thrombopoiesis
• a larger cell (megakaryocyte) forms cell fragments that live for 5-9 days
• contains many vesicles (often for substance transport)
• no nucleus
• important to hemostatis - responses to stop bleeding
• initially form a platelet (cell fragments of a larger cell, do not have nucleus) plug that later leads to blood coagulation or clotting

Question 6

Thrombocytes Platelet Plug Formation - 3 Steps

Answer 6

Step 1 – platelet adhesion
* Contact and stick to exposed collagen fibers
at damage site using endothelium and
platelet secreted von Willebrand factor
(forms bridge).
Step 2 – platelet activation
* Adhesion triggers platelets to release vesicle
contents.
* Release of adenosine diphosphate (ADP) and
serotonin trigger multiple changes in
metabolism, shape, and surface proteins of
local platelets.
* Synthesis of thromboxane A2 and released
into blood activating/attracting circulating
platelets and promoting vasoconstriction
(platelets closer together)
Step 3 – platelet aggregation
* Changes make platelets sticky to one
another forming an accumulating mass
(platelet plug).
* Prostacyclin (PGI2) and nitric oxide (NO)
release from healthy endothelium
prevents platelet steps.
* Keeps in check size and extent of spread
of platelet plug (keeps local).

Question 7

Blood Coagulation

Answer 7

conversion of blood to solid gel (a clot or thrombus);
forms around platelet plug
procoagulant – promotes coagulation
* Thrombin, calcium, clotting factors (roman numerals),
vitamin K – all involved in clotting cascade.
anticoagulant – opposes coagulation
* secretion of tissue factor pathway inhibitor (TFPI) and
antithrombin III / activating protein C – inactivate
thrombin or clotting factors.
* drugs: aspirin – blocks platelet plug formation,
heparin – blocks thrombin, warfarin – blocks vitamin K
formation.
dissolving clots already formed
* especially inappropriate clots; clot removal once
repair is done.
* fibrolytic system – plasmin activation to dissolve clot

Question 7

Blood Coagulation

Answer 7

conversion of blood to solid gel (a clot or thrombus);
forms around platelet plug
procoagulant – promotes coagulation
* Thrombin, calcium, clotting factors (roman numerals),
vitamin K – all involved in clotting cascade.
anticoagulant – opposes coagulation
* secretion of tissue factor pathway inhibitor (TFPI) and
antithrombin III / activating protein C – inactivate
thrombin or clotting factors.
* drugs: aspirin – blocks platelet plug formation,
heparin – blocks thrombin, warfarin – blocks vitamin K
formation.
dissolving clots already formed
* especially inappropriate clots; clot removal once
repair is done.
* fibrolytic system – plasmin activation to dissolve clot