Circulatory System Flashcards
what does the circulatory system do?
transportation, homeostasis, protection
what does the circulatory system transport?
nutrients (O2, ions), waste, hormones
what does the circulatory system maintain homeostasis for?
maintains body temp, and fluid/ solute levels in cell
why is it important for cell to maintain homeostasis of body temp?
for enzymes to work optimally
how does the circulatory system provide protection?
immune system defends against foreign materials
what are the 3 main parts of the circulatory system?
the heart, blood vessels, blood tissue
what is the heart (formal definition)?
muscular organ, which pumps blood through blood vessels of the circulatory system
what are the blood vessels (formal definition)?
channels or conduits through which blood is distributed to body tissues
what is blood classified as?
a tissue
what is blood (formal definition)?
body fluid that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells
how big is the heart?
about the size of the fist
where is the heart located?
between the lungs and thoracic cavity. middle
what is the heart protected by?
sternum in the middle of the rib cage
what is the sternum?
hard bone that helps protect the heart
what side of the heart is bigger? what does that mean?
the left side of the heart is bigger than the right. this makes the left side louder and easier to hear.
what is the heart surrounded by?
pericardium
what is the pericardium?
a fluid like membrane that allows there to be no friction or damage when the heart is beating
what is the average heart beat rate?
70 beats/ min
when does heart rate increase?
faster when stressed or during exercise
what does the heart consist of?
two parallel pumps that contract at the same time
what are the two pump separated by?
the septum
what do the muscle contracts mirror?
muscle contractions on right side mirror the muscle contractions on the left side
what does the pump on the right side recieve? where does it send it?
deoxygenated blood from the body systems. it pumps it to the lungs.
what circulation are vessels that carry blood to and from the lungs a part of?
pulmonary system
what does the pump on the left side recieve? where does it send it?
oxygenated blood from lungs and pumps it to the cells of the body.
what circulation are vessels that carry blood to and from the body cells?
systemic circulatory system
how many chambers does the heart have?
four chambers
what are the two thin walled chambers called?
atria - atrium (singular)
what are the two thick walled chambers called?
ventricles
what do the atria act as?
holding chambers for blood that enters from either the systemic or pulmonary circuit
what are arteries?
vessel carrying blood away from heart (usually oxygenated)
what are veins?
vessel carrying blood to heart (usually deoxygenated)
what are exceptions to oxygenated / deoxygenated, arteries/ veins
pulmonary vein and artery
what is the superior vena cava?
a type of vein that carries deoxygenated blood from the head to the right atrium
what is the inferior vena cava?
a type of vein that carries deoxygenated blood from tissues of the body to the right atrium
what are the pulmonary veins?
the type of vein that carry oxygenated blood from the lungs into the left atrium
what are pulmonary arteries?
the type of artery that carries deoxygenated blood from the heart to the lung. once it’s in the lungs, blood gets O2 by diffusion, and returns to the left side.
what is the aorta?
the largest artery. it carries oxygen-rich blood away from heart to body tissues. this branches off into all other major arteries
what are the coronary arteries?
arteries that branch of the aorta. they supply the heart muscle with blood.
why does the heart muscle need blood?
because it needs ATP.
how many ways does blood move? what makes this possible?
one way because of valves.
what is prolapse of blood?
blood going backwards
what prevents prolapse?
the atrioventricular valve.
what does the atrioventricular valves separate?
the atrium from the ventricle on either side of the heart
how many flaps of tissue does the right AV valve have?
3 - called tricuspid
how many flaps of tissue does the left AV valve have?
2 - bicuspid
what are the valves supported by?
chordae tendineae
what are the semilunar valves?
valves found where the blood vessels attach to the heart. it helps prevent blood from the blood vessels prolapsing into the ventricles again
what is the sound the heart makes?
lubb dubb
what makes the heart sound?
by the closing of the heart valves
what is systole?
contraction
what is diastole?
relaxation
when does the lub sound happen?
when the AV valve closes
when does the dub sound happen?
when the semilunar valve closes
explain the cardiac cycle.
- heart muscle is completely relaxed to get blood into atria.
- when the atria fills up, it contracts, forcing blood into the ventricle
- ventricle contracts, forcing blood up artery
do the atria and ventricle contract at the same time?
no
where does the cardiac muscle appear?
only in heart
what does the cardiac muscle display?
a branching pattern. it appears striated when viewed under a microscope.
does cardiac muscle need external nerve stimulation?
no it can contract on its own
what is the cardiac muscle called?
myogenic muscle
what is the heart tempo set by?
a bundle of specialized nerves and muscles located where the vena cava enter the right atrium
what is the pacemaker?
the sinoatrial node
explain the node system.
the sinoatrial node initiates each cardiac cycle. a group of cells sends out a stimulus to generate an electrical signal. the electrical impulse travels down right and left atria. the atrioventricular node picks up the impulse from the SA node, and relays it on the AV bundle (bundle of his). the impulse travels down the septum and spreads over the ventricle, causing it to contract upwards.
how can contractions be made faster or slower?
the brain can adjust it
what happens if the pacemaker malfunctions?
doctors can monitor and implant a pacemaker to ensure it beats regularly.
what is an electrocardiograph?
ECGS monitor electrical activity of the heart. waves are produced as specific events of the cardiac cycle occur. it helps to diagnose heart problems.
explain the PQRST wave.
p - atrium contracting
qrs - ventricle contracting (biggest wave)
t - recovered ventricle
what factors can change the pace of a heart? explain.
activity level - CO2 level (not O2 level)
stress - sympathetic (fight/flight muscles)
excitement
what part of your brain sends messages to SA node?
the medulla
what do sympathetic nerves do?
increase the rate. speed up, more force/ pressure, increase stroke volume and cardiac output.
what do parasympathetic nerves do?
decrease the rate. slow down, less force/ pressure, decrease stroke volume and cardiac output.
what is cardiac output?
the amount of blood your heart pumps each min
what is the average cardiac output?
5 - 6 L in an average adult at rest
what is another word for heart rate?
pulse
how do you measure heart rate?
full beats / min
what is heart rate essentially measuring?
the amount of times the ventricle contracts
what is stroke volume?
blood pumped by one contraction of the ventricle
what is cardiac output equal to?
stroke volume x heart rate
what type of relationship do stroke volume and heart rate have?
inverse. the higher the stroke volume, the lower the heart rate.
how can cardiac output be changed?
with O2 demands
how do circulatory vessels differ?
structure, volume of inner lumen, and direction of flow and pressure.
what are arteries?
blood vessels that carry O2 rich blood away from the heart
how many walls does an artery have?
3 thick walls
what are the walls of an artery?
- outer - rigid connective tissue
- inner - rigid connective tissue
- middle - muscle fibers and elastic tissue
what is the pressure in an artery?
high pressure - blood surges out
why can you feel your pulse?
you feel your pulse because of changes in the diameter of the artery after heart contractions
can blood in arteries clot?
no because pressure is too high, so blood is moving fast. not enough time to clot.
what are arterioles?
fine branches from arteries
what are arterioles made of?
elastic fibers and smooth muscle
how are arterioles regulated?
through nervous system
what do arterioles do?
maintain pressure
where is blood from arteries passed on to?
arterioles
what is the pressure like in arterioles?
low pressure
where does the diameter of a vein change?
as it gets closer to the heart
what are veins?
blood reservoirs ( 50% of total blood volume can be found in veins). carry deoxygenated blood towards the heart
do veins have less or more elastic?
less because pressure is less
is the pressure in veins high or low?
low so blood oozes out
what do veins have that allow them to steer blood to the heart?
valves. the valves allow blood to pool rather than flowing backwards. muscle contractions cause venous pressure to increase. increased pressure causes valves to open.
what are capillaries composed of?
single layer of epithelial cells
what are capillaries the site of?
fluid and gas exchange between blood and body cells
are capillaries tiny or big? explain what this means for RBC.
they are narrow and tiny so RBC have to travel in a single file line
are capillaries easy or hard to break?
easy
what does breaking a capillary lead to?
bruising
do capillaries have a high or low cross sectional area?
high because there is so many of them
what is diffused out of the capillary wall?
oxygen from the blood
do capillaries have lower or higher pressure?
lower because there is larger area and diameter
why is it beneficial that the capillary wall is a single layer wall?
easier for nutrients and wastes to diffuse in/ out
what are lymph vessels?
one way system from tissues to the heart. slow. build up can cause swelling.
what causes smooth muscle cells to contract?
a nerve impulse. this reduces the diameter of the blood vessel
what does it mean when the diameter of a blood vessel is reduced?
vasoconstriction. helps increase blood pressure. decreases blood flow to tissues when not needed.
what is nicotine?
a vasoconstrictor
what is vasodilation?
increases the diameter of the blood vessel. which increases nutrient transport due to relaxation of the muscle.
why does blushing happen?
heat needs to be released, so blood flows to the skin because it has a large SA. vasodilation happens and heat is released.
what is blood pressure a measure of?
how much blood there is pushing forward and sideways and pressure that is there as it relaxes.
what instrument is used to measure BP?
sphygmomanometer
what is a sphygmomanometer also called?
BP cuff
what are the two numbers that come from BP?
top - max pressure (when ventricles contract) - systolic
bottom - when ventricle relaxes - diastolic
how is BP an indicator of health?
can tell us how stretchy the arteries are. can tell us if arteries are getting clogged.
what is normal BP?
120 over 80
what is low BP lead to?
not getting enough blood in certain area
what does it mean when you are light headed?
BP is adjusting
where does low BP come from?
loss of blood volume
what diseases is high BP associated with?
heart disease
what factors influence BP?
weight, fitness level, diseases (diabetes), diet, lifestyle factors, genetics, and stress
what is arteriosclerosis?
build up of fatty tissues in the lumen of arteries. diet exercise and genetics are key factors.
what is arteriosclerosis often associated with?
coronary artery blockage
what is angina?
reduced blood flow through the coronary arteries due to arteriosclerosis. heart muscle weakens and cannot pump fast enough. there is a cramp in the muscle. the muscle starts building up lactic acid. it is painful
what is a heart attack?
complete blockage of a coronary artery so no O2 is going to the heart. the muscle dies
what is bypass surgery?
if the blockage is known about then bypass surgery happens. the vegin from legs is taken and atached to the beginning and end of the blockage to let blood flow through.
explain an angioplasty.
- the build up of cholesterol partially blocking blood flow through the artery
- stent with balloon inserted into partially blocked artery.
- balloon inflated to expand stent
- balloon removed from expanded stent
what are the two types of strokes?
where blood is blocked or where the vessel breaks
what happens in a stroke?
O2 is stopped from going to brain
what are erythrocytes?
RBC
what are leukocytes?
WBC
what is the function of blood?
transport, regulation/ homeostasis, protection
what does blood transport?
white and red BC, gases (O2, CO2), nutrients (Ca, glucose, amino acids, hormones)
what does blood regulate?
heat
what type of blood is taken from the body when donating blood?
whole blood
what happens to blood after drawn out of person?
placed in test tube and then centrifuge. moves solids to the side/ bottom
what is the composition of blood after centrifuge?
55% plasma, 45% formed elements
how often can plasma be donated?
every month
how often can whole blood be donated?
every 3 months
why do you need 3 months till you can donate whole blood again?
because the RBC have to be replenished.
where are blood cells made in?
bone marrow
what is plasma made of?
- water because it a solvent
- ions (electrolytes) - Na, K, Ca, HCO3
- plasma proteins: fibrinogen, immunoglobulins (antibodies)
- nutrients, wastes, gases, hormones
what are the cellular elements made of?
- 5-6 million RBC (most) because they transport O2 and CO2
- 5000 - 10000 WBC - defence and immunity
- platelets
what is the shape of RBC?
biconcave
why is that the shape of RBC?
because increases SA
what is on the RBC?
hemoglobin
what does a RBC consist of?
membrane and hemoglobin. no nucleus or DNA
what does it mean if the RBC doesn’t have a nucleus or DNA?
cannot reproduce
what does a hemoglobin consist of?
4 polypeptide chains and 4 heme (iron) groups
how many O2 molecules can a hemoglobin carry?
4
how many hemoglobins are there on an RBC?
270 million
what type of binding does hemoglobin have?
cooperative binding. if one O2 binds, hemoglobin changes shape, and O2 affinity increases.
where does the O2 from hemoglobin go?
active tissues
in what environments does O2 dissociate with hemoglobin easily?
where high CO2 concentrations
do hemoglobins have a higher affinity for CO2 or O2?
CO2
where are RBC created from?
stem cells in bone marrow
what determines the number of RBC?
the number of O2 available
how is the number of O2 available determined?
the need of O2. men have more RBC than women because they are bigger. people at higher altitudes have more RBC because less O2.
what are the 3 ways CO2 is transported? which is the main way?
- dissolved (bubbles)
- binds to hemoglobin - carbaminohemoglobin
- (MAIN) becomes bicarbonate ions - bicarbonate is a buffer (doesn’t let pH change)
how many WBC are there compared to RBC?
way less
do WBC have a nucleus or no?
have a nucleus, so they can reproduce
what happens to WBC when there is an infection?
WBC count goes up
where are WBC produced?
some in bone marrow. other are modified by lymph nodes
do platelets have nucleus’?
no, so they cannot reproduce
explain platelets.
irregular shaped. look jagged. very fragile. will rupture if they strike a sharp edge
explain blood clotting.
platelets break and release clotting factor. Ca2+ goes to prothrombin and converts it to thrombin. thrombin goes to fibrinogen and converts it to fibrin
what is fibrin?
a long protein that forms a mesh to stop RBC, to stop blood from going forward. forms a clot
what is anemia?
not enough RBC or not enough hemoglobin
what is leukemia?
cancer of WBC (too many WBC)
what is hemophilia?
unable to clot
what is lymph?
the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to the central circulation.
