KIN 132 Quiz 1: CV 1-4

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

1. Platelet adhesion
2. Platelet activation
3. 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

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* 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

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* 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

1. stimulus (disruption)
2. controlled variable → controlled variable is monitored by…
3. receptor → receptors send action potentials/chemical signals to…
4. control center → that recieves the input and porvides action potentials or chemical signals to…
5. effectors → that bring about a change or…
6. 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

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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