Cardiovascular System - Blood Components

what are the “formed elements” of blood? what do they float in?

-erythrocytes (RBC), leukocytes (WBC), platelets

^ these float in plasma

blood = 55% plasma, 45% rbc, 1% wbc

albumin, fibrinogen, and globulins are proteins found where?

plasma of blood

what is the function of albumin?

maintains osmotic pressure for gas/nutrient exchange in capillaries

where does hematopoiesis occur? hematopoiesis: making of formed elements

red bone marrow

hematopoiesis starts with __ stem cell. this stem cell then differentiates into 2 kinds of stem cells

- what do they each make at the end?

-how?

hemocytoBLASTS stem cell

1. lymphoid stem cells → lymphocytes (t-cells, b-cells, nk-cells)

2. myeloid stem cells → erythrocytes, platelets, and leukocytes (monocytes, neutrophils, eosinophils, basophils)

myeloid and lymphoid stem cells create pre-cursor cells that end with “-blast”, which then goes thru several cell divisions to become their final product

ex: erythroblasts → erythrocytes; monoblasts → monocytes

the myeloid stem cells proliferate to create which part of the blood

makes the formed elements: erythrocytes, platelets, and leukocytes (monocytes, neutrophils, eosinophils, basophils)

what do RBCs lack and why is this a benefit?

they lack a nucleus - creates a larger surface area for gas exchange bc the cell is depressed in the middle

what does oxygen bind to in a hemoglobin?

o2 binds to the Fe2+ ion, (iron)

there are 4 x Fe2+ ions in each hemoglobin = 4 o2 molecules in each hemoglobin

erythroPOIETIN - is a hormone that monitors whether the body needs more oxygen to meet its current state/demand. what is its job when low blood oxygen is detected? where is this hormone made?

erythropoetin is made from the kidneys

• erythropoietin stimulates more erythroblasts in the red bone marrow = ^ RBC production!!!/more erythrocytes made = able to deliver more o2

if there was damage to the kidneys (which produces erythropoietin) what would happen to the # of RBCs made?

decrease.

erythropoietin tells red bone marrow to make more RBCs [when needed]

if the body detected low blood o2, what would be secreted first?

erythropoietin from the kidneys > to tell red bed marrow to produce more RBCs so that it can carry more o2 to wherever its needed

old RBCs get broken down in the spleen.

-what eats them up

-what happens when hemoglobin is broken down?

-how is bile created?

-how does it get excreted out of the body?

macrophages eat them up

hemoglobin broken down into: globin chains & heme

• iron from heme goes back to red bone marrow for re-use

• the rest of the heme gets converted into bilirubin

bilirubin binds to albumin and gets transported to the liver which then turns to bile

excreted via feces

what is normal hemocrit %? (% of RBC/total blood volume)

45%

type AB blood group

• what antigens does it have

• which antibodies does it have

• what blood can it receive

1. A & B antigens

2. none

3. any, a/b/ab/o

type A blood group

• what antigens does it have

• which antibodies does it have

• what blood can it receive

1. A antigens

2. B antibody

3. A and O

type B blood group

• what antigens does it have

• which antibodies does it have

• what blood can it receive

1. B antigen

2. A antibody

3. B and O

type O blood group

• what antigens does it have

• which antibodies does it have

• what blood can it receive

1. none

2. A and B antibodies

3. only O

which WBC are in the granulocytes group? - visible granules in cytoplasm

neutrophils, eosinophils, basophils

which WBCs are in the agranulocytes group? - no visible granules

lymphocytes and monocytes

which WBCs are the main phagocytes?

neutrophils (main one) and monocytes

what would cause a high number of eosinophils?

parasitic infection (tapeworms, etc.) or allergic reaction

what would cause a high number of basophils?

allergic reaction

basophils have histamine in their granules → leads to intensifying inflammation and histamine effect

which WBCs attack infections, tumour cells, and rejects transplanted organs?

lymphocytes: t-cells, b-cells, nk-cells

which WBC turn into macrophages and fight chronic infections?

monocytes

what do platelets lack in their cell structure? and what is its function?

lack a nucleus

hemostasis: blood clotting — to stop bleeding (from small injury)

this describes which stage of hemostasis (blood clotting)

• smooth muscles of blood vessels constrict, decreasing the blood flow to injury site (slows down blood loss)

vascular spasm

this describes which stage of hemostasis (blood clotting)

• platelets adhere to collagen fibres of blood vessels

• platelets make themselves “sticky” so more platelets adhere to plug up the cut in the vessel

formation of platelet plug

this describes which stage of hemostasis (blood clotting)

• fibrin threads tighten up the clot and traps RBCs

coagulation/blood clotting

the heart is located in the __

mediastinum

describe the layers of heart from outer to inner

pericardium (fibrous; serous) > epicardium > myocardium > endocardium

myocardium: cardiac muscle

tricuspid valve

in between right atrium/right ventricle

bicuspid valve

in between left atrium/left ventricle

pulmonary semilunar valve

in between right ventricle and pulmonary artery

aortic semilunar valve

in between left ventricle and aorta

semilunar valves prevent blackflow during when

during ventricular diastole

(prevents backflow from arteries back into ventricles)

what does systole and diastole mean

systole: ventricle contraction

diastole: ventricle relaxation

what kind of blood is carried in

• pulmonary arteries vs. veins

pulm. artery: de-oxygenated blood - going to the lungs

pulm. veins: oxygenated blood - back to heart

what node is the heart’s natural pacemaker? how does it work?

Sino-atrial node (SA node)

-this initiates electrical impulses that regulates a regular heart rate

describe conduction system of heart starting with SA node

SA node > atrio-ventricular node (AV node) > bundle of His > Purkinje fibers = ventricular contraction

describe contraction phases of cardiac cycle - where is the blood/going to + which valves are open

1. atrial contraction

2. iso-volumetric contraction

3. ventricular ejection/contraction

Atrial contraction (aka atrial systole):

• final pump of atrium to push all the blood into the ventricles - AV valves open

Iso-volumetric contraction:

• for a split second, all 4 valves are closed but all the blood is in the ventricles

• muscles around ventricles are isometrically contracting (think: keeping core tight, bracing itself for big push)

Ventricular systole:

• SL valves open, full contraction of ventricles to eject blood out from heart (at the same time this happens, blood is starting to pool in atria)

describe relaxation phases of cardiac cycle - where is the blood/going to + which valves are open

1. Isovolumetric relaxation

2. Ventricular filling (aka atrial diastole)

Iso-volumetric relaxation:

• for a split second where all 4 valves are closed again and ventricular blood volume doesn’t change - ventricles relax

Ventricular filling (atrial diastole):

• AV valves open, blood flows from atria into ventricles

5 phases of cardiac cycle from atrial systole to atrial diastole

1. atrial systole

2. iso-volumetric contraction

3. ventricular systole (ejection)

4. iso-volumetric relaxation

5. atrial diastole (ventricular filling)

this is the amount of blood pumped OUT of the heart per minute

cardiac output

equation for CO = cardiac output

CO = (SV) x (HR)

• stroke volume X heart rate

this is the volume of blood ejected by the ventricles with each heartbeat

stroke volume

describe how these factors can influence Heart Rate

• autonomic n.s. (cardiac center)

• hormones (which ones)

• sodium/potassium in blood

• body temperature

• age, physical fitness, medications

autonomic n.s.:

• receives info and directs “appropriate” output onto sympathetic/parasymp. nerves (cardiac accelerated nerve or vagus nerve, respectively)

hormones:

• epinephrine and NE increase heart rate and contractility (due to exercise, stress, excitement - that releases these hormones)

Na/K+ :

• excess amount of these decreases HR and contractibility

body temp:

• cold - decreases HR, vice versa

describe how these factors influence Stroke Volume

• pre-load (stretch)

• after-load (resistance, example?)

• contractility

pre-load: think of stretching a rubber band. more stretch > more forceful contraction > more blood ejected

after-load: the resistance from arteries. heart must work harder to push out blood if theres more resistance. (for example, narrowing of arteries bc of atherosclerosis. making it harder to eject as much blood)

contractility: intrinsic strength of myocardium