anatomy and physiology of circulatory system (heart and blood) Flashcards
arteries carry blood?
away from the heart at high pressure
veins carry blood?
towards the heart at low pressure
arteries branch into?
arterioles
arterioles pass into?
capillaries which are only wide enough for a single blood cell to pass at a time
after blood passes through capillaries, it passes through?
venules
venules pass back into?
veins
all exchange of materials in the blood happen where?
capillaries
the walls of blood vessels are what type of cell?
endothelial cells
vasodilation/vasoconstriction is when?
secretion of substances (like nitric acid) and endothelium regulate vessel diameter to maintain blood pressure, tissue oxygenation, and thermoregulation
inflammation is when?
release of inflammatory chemicals from injured tissues stimulate endothelial cells to increase their expression of adhesion molecules which allow WBC to adhere to the endothelial cell to enter injured tissue
angiogenesis is?
then formation of new blood vessels
ex: many tumors secrete angiogenic growth factors to increase blood supply thus angiogenesis inhibitors are drugs used to restrict blood flow to tumors
thrombosis is?
blood clotting
*undamaged endothelial cells secrete substances to inhibit coagulation to prevent life-threatening clots
pulmonary circulation is defined as?
flow of blood from the heart to the lungs and back to the heart
systematic circulation is defined as?
flow of blood from the heart to the rest of the body and back again
one exception to circulation system is the hepatic portal system, which is when?
blood passes first through capillaries in the intestine, the collects in veins to travel to the liver where the vessels branch and blood passes again through capillaries
*important for nutrients directly from intestine to liver
second exception to circulation system is the hypothalamic-hypophysial portal system, which is when?
blood passes through capillaries in the hypothalamus to the portal veins, then to capillaries in the pituitary
*important for hormones from hypothalamus directly to pituitary
atrioventricular valves are located?
between each atrium and ventricle
the AV valve between the left atrium and left ventricle is the?
bicuspid/mitral valve
the AV valve between the right atrium and right ventricle is the?
tricuspid valve
the semilunar valve between right ventricle and pulmonary artery is?
pulmonary semilunar valve
the semilunar valve between left ventricle and aorta is?
aortic semilunar valve
what happens during diastole?
ventricles are relaxed and atria contract
blood is able to flow into ventricles from the atria
what happens during systole?
ventricles contract and atria relaxed
blood is pushed out of ventricles towards pulmonary artery or aorta
*lub dup sound
heart rate/pulse is the?
number of times the “lub-dup” cardiac cycle is repeated per minute
stroke volume is?
the amount of blood pumped with each systole
cardiac output is?
the total amount of blood pumped per minute
the heart is what type of muscle?
cardiac muscle (involuntary)
the cardiac muscle is functional syncytium, meaning?
that the tissues’ cytoplasms communicate via gap junctions
gap junctions of the cardiac muscle are found in?
intercalated disks which is the connection between cardiac and muscle cells
the initiation of each action potential to start each cardiac cycle occurs automatically within the heart itself by?
the SA node located in right atrium
the SA (sinoatrial) node acts as a?
pacemaker and is divided into three phases
membrane potential in cardiac muscle cell
phase 0 is depolarization, what happens?
AP simulates myocytes to reach threshold causing the
fast Na+ channels open
Na+ influx
membrane potential in cardiac muscle cell
phase 1 is initial repolarization, what happens?
Na+ channels inactivate and K+ channels open causing
K+ efflux
membrane potential in cardiac muscle cell
phase 2 is plateau, what happens?
the Na+ influx from phase 0 causes Ca2+ channels to open, so Ca2+ influx
K+ channels are still open so K+ efflux are balanced leading the equilibrium
membrane potential in cardiac muscle cell
phase 3 is repolarization, what happens?
Ca2+ channels close but K+ remain open for K+ efflux
membrane potential in cardiac muscle cell
phase 4 is resting membrane potential, what happens?
inward and outward are equal thus K+ closes
the SA node spreads throughout the atria causing them to ?
contract and fill ventricles
the SA node triggers the AV node which?
continues electrical impulse to the AV bundle (bundle of His)
the AV bundles divided into what two sections?
left bundle branches and purkinje fibers
why does the AV bundles divide into left bundle branches and purkinje fibers?
to allow impulse to spread rapidly and evenly over both ventricles
what controls the SA node?
the vagnus nerve which the preganglionic axons of it synapose in the ganglia near the SA node
what neurotransmitter is released by the vagus nerve to inhibit depolarization by binding to receptors on the cells of the SA node?
acetylcholine
hemodynamics is?
the study of blood flow
what is the driving force of blood flow?
difference in pressure from arteries to veins
blood pressure is systemic arterial pressure is, this is the measurement of?
force per unit area exerted by blood upon the walls of arteries
the typical bp is 120/80 where the numbers mean?
120mmHg is the systolic pressure which is the highest pressure that ever occurs in the circulatory system
80mmHg is the diastolic pressure which is the lowest pressure that ever occurs in the circulatory system
what measures blood pressure?
sphygmomanometer
local auto-regulation is the process known as?
when tissues in need of extra blood flow are able to requisition it themselves
blood is composed of?
plasma and formed elements
plasma accounts for 54% of blood volume is consists of what items?
electrolytes, buffers, sugars, blood proteins, lipoproteins, co2, o2, and metabolic waste
buffers in the blood are there to? what is the primary one?
maintain a constant pH of 7.4
bicarbonate (HCO3-)
via the reaction CO2+H2O=H2CO3=HCO3-+H+
the electrolytes of the blood are?
sodium, potassium, chloride, calcium, and magnesium
the blood protein, albumin is for?
maintenance of oncotic pressure which is the osmotic pressure in capillaries from plasma proteins
the blood protein, immunoglobulins are for?
immune system
the blood protein, fibrinogen is for?
blood clotting (hemostasis)
lipoproteins of the blood are particles consisting of?
fats, cholesterol, and carrier proteins
the main metabolic waste product of blood is?
urea which is essentially a carrier of excess nitrogen
bilirubin is another blood waste product which is used for?
breakdown product of heme
what is another term for RBC?
erythrocytes
when centrifuged, the volume of blood that only has RBC is called the? and is what % of whole blood?
hematocrit - 45%
what is another term for WBC?
leukocytes
leukocytes and platelets make up what % of blood volume?
1%
what hormone stimulates RBC production? and where does this production take place?
erythropoeitin (hormone from kidney)
production in the bone marrow
RBC lack a mitochondria thus rely on what for ATP synthesis?
glycolysis
the purpose of RBC are to?
transport o2 to tissues from the lungs and co2 from tissues back to the lungs
what shape are typical RBC? why?
flat and biconcave to increase surface area of hemoglobins to bind to oxygen
what is blood type based on?
presence or absence of specific antigens
what are the two most important blood antigen groups?
ABO blood group
Rh blood group
hemolytic disease of the newborn/erythroblastosis fetalis is when?
mother is Rh- and carrying a Rh+ baby
a person with A+ blood will produce what type of antibodies?
anti-B antibodies so that it will clump and destroy B cells
granulocytes are class of WBC including?
neutrophils, eosinphil, and basophil
lymphocytes are class of WBC including?
T cells and B cells
monocytes are class of WBC including?
macrophages
what WBC is phagocytic to bacteria and creates pus?
neutrophils
what WBC is the most abundant?
neutrophils
what WBC destroys parasites and are modulators to allergic reactions?
eosinophils
what WBC stores and releases histamine for allergic reactions and attracts other WBC to inflamed sites?
basophils
what WBC is the rarest?
basophils
what WBC mature into plasma cells that produce antibodies?
B cells
what WBC control immunity and attack virus infected cells/tumor cells?
T cells
what WBC is phagocytic to debris and microorganisms and activate lymphocytes (T and B cells)?
macrophages
what WBC is the largest in size?
macrophages
platelets are small fragments of what?
megakaryocytes, which are derived from thrombopoietin
the purpose of platelets are to?
aggregate at site of damage to a blood vessel wall to for platelet plug to stop bleeding and activate other clotting factors
when none of the four subunits of hemoglobin are bound to, what confirmation happens? and what is the affinity?
tense and has low affinity for o2
when o2 does bind, it becomes relaxed and affinity increases
hemoglobin binds oxygen cooperatively, meaning?
the confirmation change in one subunit, activates the affinity for other subunits to bind
bohr effect happens when what factors stabilize tense hemoglobin and reduce oxygen affinity?
decreased pH, increase Pco2, and increased temperature
what are the three ways carbon dioxide is transported in the blood?
conversion of co2 to carbonic acid which dissociates into bicarbonate and proton by carbonic anhydrase enzyme (73%)
being stuck to hemoglobin by binding to other sites on the protein (20%)
co2 is water soluble therefore dissolve in blood more so than o2 does (7%)
