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3 CV components to focus on in course
Heart - pump, driving force
Blood vessels (vascular system) - passageways, circulation
Blood - fluid connective tissue, medium
How much blood is in your body?
around 8% of body weight
around 5 litres of blood volume
2 components of blood by volume
plasma
cellular elements
Components of plasma
water
proteins
other solutes
Cellular elements of blood
eythrocytes - red blood cells
leukocytes - white blood cells
thrombocytes - platelets
Eythrocytes
red blood cells
Leukocytes
white blood cells
Thrombocytes
platelets
How much water is in plasma?
Over 90%, it is the fluid portion
Where are plasma proteins produced?
in the liver
Solutes in plasma
electrolytes (socium, postassium, chloride, etc.)
nutrients (carbohydrates, fats, proteins, vitamins, minerals)
wastes (urea, creatinine, bilirubin)
gases (oxygen, carbon dioxide)
regulatory substances (hormones, enzymes)
Fluid compartments (of blood?)
Extracellular fluid (outside cells)
Intercellular fuild (inside cells)
Extracellular fluid
outside cells
plasma - outside cells in the blood
interstitial fluid - outside cells in tissues
Intracellular fluid
inside cells
Compartment shifts
under certain conditions fluids get exchanges between compartments.
plasma fluid can move to interstital
intracellular can move to extracellular
What does plasma do?
delivers things where needed (e.g. carbs) and removing things that are waste (e.g. breathing out Co2)
Where are blood cells formed?
inside red bone marrow
Which cell can form all mature blood cell lines
pluripotent hematopic stem cell
myeloid stem cells
can form a range of mature blood cells lines
Lymphoid stem cells
can form lymphocytes only
precursor cells (blast cells)
committed to forming a particular mature blood cell line
thrombocyte
A thrombocyte, also known as a platelet, is a small, irregularly shaped cell fragment found in the blood. Its main function is to aid in blood clotting, preventing excessive bleeding. Thrombocytes are produced in the bone marrow and play a crucial role in hemostasis, the process of stopping bleeding from damaged blood vessels.
precursor cells
Cells that have the potential to develop into different types of specialized cells in the body. They are early-stage cells that can undergo differentiation to become specific cell types, such as blood cells, nerve cells, or muscle cells. Precursor cells play a crucial role in tissue repair, regeneration, and growth.
blood precursor cells
proerythroblast, megakaryoblast
Thrombocytes
Small, cell fragments in the blood responsible for clotting. They help to prevent excessive bleeding by forming blood clots at the site of injury. Also known as platelets.
Flashcard: Thrombopoiesis
Process of platelet production in the bone marrow. Involves differentiation of megakaryocytes, which release platelets into the bloodstream. Essential for blood clotting and hemostasis.
What does a myeloid stem cell lead to?
megakaryoblast which forms a large megakaryocyte
Platelets
pieces of megakaryocyte that break off as cell fragments
Does a platelet have a nucleus?
No
How long do platelets live?
5-9 days
What do the vesicles in a platelet do?
transport a substance or substances
Why are platelets important to homeostasis?
Responses to stop blood loss (opposite of hemorrhage)
3 steps in platelet role in hemostasis
Platelet adhesion
Platelet activation
Platelet aggregation
Platelet adhesion
Platelets contact and stick to exposed collagen fibres at damage site using von Willebrand factor secreted by damaged endothelium and platelets (forms bridge).
Platelets adhere to damage site; form a bridge
von Willebrand factor
Essential blood protein
Helps platelets stick to damaged blood vessels
Facilitates blood clot formation
Promotes hemostasis (blood clotting)
Platelet activation
Adhesion triggers platelets to release vehicle contents into the blood including:
Adenosine diphosphate (ADP) and serotonin - trigger activation of local platelets (multiple changes in shape, metabolism, and surface proteins)
synethsis and release into blood of thromboxane A2 - trigger activation and attraction of circulating platelets to damage site
Platelet aggregation
activation changes make platelets sticky to one another, forming an accumulating mass (platelet plug)
prostacyclin (PGI2), and nitric oxide (NO) release from healthy endothelium prevent platelet steps
Keeps in check size and spread of platelet plug (local at damage site)
Aspirin - blocks steps in platelet plug formation
Blood coagulation/blood clotting
conversion of blood to solid state; forms around initial platelet plug location
The 2 forces that are balanced in blood clotting
procoagulant, anticoagulant
procoagulant
the force in blood clotting that promotes clotting
damage site starts a clotting cascase (clotting factor activations) and calcium release / leads to circulating fibrinogen (inactive) being converted into fibrin (active) which forms a mesh network at damage site.
material (blood cells, platelets, proteins) becomes trapped in mesh/material plus mesh network forms clot
What force involves a clotting cascade?
Procoagulant
anticoagulant
opposes clotting
secretion: tissue factor pathway inhibitor, antithrombin III / activation: protein C / drugs: heparin, warfarin
these all inactive clotting factors blocking steps in clotting cascade
When does dissolving clots happen?
once the repair is done, or if clot forms at an inappropriate location
How clots are dissolved
activate fibrinolysis (clot dissolving)
plasminogen (inactive) incorporated into clot as formed
release of a plasminogen activator by endothelial cells converts plasminogen (inactive) to plasmin (active) dissolve clot
Intravascular Clots
Blood clots that form inside blood vessels, obstructing blood flow. Can lead to serious complications like heart attacks or strokes.
2 types of intravascular clots
thrombus, embolus
thrombus
blood clot attached to inner vessel wall
embolus
free floating clot; often small piece of thrombus that has broken free
fibrinolysis
clot dissolving process
Steps in fibrinolysis
plasminogen (inactive) is incorporated into clot as formed, release of a plasminogen activator by endothelial cells converts plasminogen (inactive) to plasmin (active) to dissolve clot
What risk does intravascular clots create?
occlusion - blockage of blood vessel
intravascular clot of the coronary blood vessel
myocardial infraction (heart attack)
intravascular clot of the cerebral or cerebellar blood vessels
stroke
intravascular clot: deep vein thrombosis
especially problematic for legs; long periods of sitting (air travel concern)
atherosclerosis
plaque (fatty substances, cholesterol, cellular waste, etc.) forms on inner artery wall.
occlusion risk
plaques often rupture, triggering a thrombus to form at site or can lead to a piece breaking away as an embolus/cycle of repeated plaque rupture - clot growth can be rapid.
erythrocyte
Definition: Blood cell responsible for carrying oxygen to the body's tissues.
Key facts: Also known as red blood cells. Contains hemoglobin, giving it its red color.
Function: Transports oxygen from the lungs to cells and removes carbon dioxide.
Structure: Biconcave disc shape, lacks a nucleus.
Abundance: Most abundant type of blood cell in the body.
Disorders: Anemia, sickle cell disease, and polycythemia affect erythrocytes.
How long do erythrocytes live?
around 120 days
shape of erythrocytes
biconcave disc - quite flexible; high surface to volume ratio.
Organells in a erythrocyte
no nucleus or other organelles
hemoglobin (hb)
Protein found in red blood cells that carries oxygen from the lungs to the body's tissues and transports carbon dioxide back to the lungs for exhalation.
Hemoglobin structure
4 globin chains (2 alpha / 2 beta)
4 hemes (each with iron ion in core)
Flashcard: "Heme Binding"
Process where heme molecule attaches to a protein. Allows proteins like hemoglobin to transport oxygen in the body.
oxygen heme binding
oxyhemoglobin
carbon monoxide heme binding
carboxyhemoglobin
globin binding - carbon dioxide
carbaminohemoglobin
globin binding - hydrogen
deoxyhemoglobin
erythropoiesis
Process by which red blood cells are produced in the bone marrow.
How long does erythropoiesis take?
15 days
homeostasis
The ability of an organism to maintain a stable internal environment despite changes in external conditions. It involves processes like temperature regulation, pH balance, and blood sugar control.
The steps in homeostasis
stimulus (disruption)
controlled variable → controlled variable is monitored by…
receptor → receptors send action potentials/chemical signals to…
control center → that recieves the input and porvides action potentials or chemical signals to…
effectors → that bring about a change or…
response → that alters the controlled variable
then return to homeostasis when the response bring the controlled variable back to normal
in erythropoiesis, what is the stimulus?
decrease in oxygen level, aka hypoxia
in erythropoiesis, what is the controlled variable?
the oxygen level; when hypoxia occurs, oxygen delivery to kidneys and other tissues is detected
in erythropoesis, what is the receptor(s)?
the kidney cells; detect low oxygen levels, and increase erythropoietin (EPO) secretion into the blood
in erythropoiesis, what is the control center?
the red bone marrow; myeloid stem cells in the red bone marrow turn into proerythoblasts, which turn into reticulocytes that then enter into the circulating bloodstream.
in erythropoiesis, what are the effectors?
the increase in erythrocytes (red blood cells) in the bloodstream/circulation. This happens because the Reticulocytes mature into erythrocytes in the bloodstream.
in erythropoiesis, what is the response?
increased oxygen being carried around the body/being delivered to tissues. This increased oxygen carrying capacity counters the initial hypoxia. More erythrocytes leads to more Hb to bind oxygen, which leads to greater oxygen delivery.
negative feedback (in homeostasis)
the move in the opposite direction to the initial change.
How are erythrocytes removed?
Spleen and liver filter blood and have macrophages (type of leukocyte) that engulf old or damaged erythrocytes.
what does processing of old and/or damaged erythrocytes result in?
heme and globin portions of Hb are split
what is the globin in old erythrocytes broken down into?
amino acids - released and used for protein synthesis
what happens to old iron from old erythrocytes?
transferred to liver and then red bone marrow, recycled to incorporate into new Hb
What is the heme in old erythrocytes converted into?
bilirubin, sent to liver, released into small intestine as part of bile for fat digestion - large intestine bacteria process bilirubin and products end up in urine and feces for elimination.
How does increased oxygen carrying capacity in the blood affect performance?
enhances performance
Altitude training
environmental
creates hypoxia - erythrocyte production
return to sea level for competition with elevated erythrocyte level
Blood doping (reinfusion)
remove erythrocytes and store them
creates hypoxia - erythrocyte production
after time, erythrocytes return to normal levels
before competition, reinfuse stored erythrocytes to get elevated erythrocyte level
Blood doping - inject EPO
directly stimulate erythrocyte production in red bone marrow
bypass kidney steps so hypoxia not needed.
Hematocrit (Hct)
the percentage by volume of red blood cells (erythrocytes) in your blood
How to view hematocrit
spin blood sample (BV; blood volume) in a centrifuge to seperate into:
plasma volume (PV)
“buffy coat” volume: leukocytes/platelets (quite small and usually ignored in Hct determination)
erythrocyte (RBC; red blood cells) volume
Hct (hematocrit) formula
RBC/BV
Average percentage of blood volume that is RBC (erythrocytes)
42-47%
Hematocrit (Hct) for anemia
same blood volume
reduced RBC, Hct. (30%)
What is observed in the blood with anemia?
lower oxygen carrying capacity
Sources of anemia
hemorrhagic - blood loss (wounds/ulcers/menstruation)
nutritional - lack elements for erythrocyte formation (iron-deficient; low iron levels).
developmental - damage in critical area (aplastic; red bone marrow).
hemolytic - erythrocytes destroyed (sickle-cell)
result of anemia
can lead to hypoxia issues
Hematocrit (Hct): polycythemia
same blood volume
increased RBC, Hct (70%)
What is observed in the blood in polycythemia?
higher oxygen carrying capacity
source of primary polycythemia
bone marrow tumor
source of secondary polycythemia
some altitude living cultures (e.g. Nepal), compensation for heart and lung disease
source of induced polycythemia
athletics