ch. 9 Flashcards
how does the circulatory system help maintain homeostasis
distribute nutrients, transport O2 from lungs and CO2 to lungs, maintain temp, blood clotting, etc
the flow of blood through a tissue is known as ?? inadequate flow is called? lack of O2 is called?
flow of blood is known as perfusion. inadequate flow is called ischemia. lack of O2 is hypoxia
the heart is what? what are arteries (include pressure)? what are veins (include pressure)?
heart is a muscular pump that pushes blood using vessels to lungs and body.
arteries: carry blood AWAY from heart at high pressure
veins: carry blood TOWARDS heart at low pressure
what is the sequence of small vessels starting at arteries? what occurs to pressure as vessels branch out?
arteries branch out to arterioles, to capillaries, into venules that go back to veins to the heart. as vessels get smaller, the pressure decreases
do arterioles or veins have muscular walls? if any of them do, why do they need muscular walls?
arterioles have muscular walls while veins do not. they have muscular walls to constrict or dilate when needed to control blood flow into capillaries.
what is the inner lining of vessels called? what does it have to do with inflammation?
the inner lining is made up of endothelial cells and white blood cells bind to these cells to cause inflammation
what is angiogenesis? thrombosis?
angiogenesis is formation of new blood vessels. thrombosis is blood clotting
dysfunction of endothelial cells causes what
hypertension, heart disease, etc
the right side of the heart has what blood and takes it where? what circulation is this?
blood from heart to the lungs and carries deoxygenated blood. this is pulmonary circulation
the left side of the heart has what blood and takes it where? what circulation is this?
blood from heart to the rest of the body and carries oxygenated blood. this is systemic circulation
what does having two circulation pathways solve?
it allows more blood to pass through only one set of capillaries except portal systems
what are portal systems? what are the two that we have?
portal systems are an arrangement by which blood collected from one set of capillaries passes through a large vessel to another set of capillaries before going back to the heart. the two we have is the hepatic portal system and the hypothalamic-hypophysial (hypothalamus to pituitary)
the heart has two chambers?
the heart has atria that are reservoirs or waiting rooms where blood collects before getting pumped into ventricles. the other chamber is the ventricle that is muscular and pump blood out at high pressures into the arteries.
where does each side of the atria/ ventricle get their blood from (include vessels that supply it)?
the right atria gets deoxy blood from veins called inferior vena cava and superior vena cava and sends it to the ventricle to pump to pulmonary artery. the left atria gets blood from the pulmonary vein to send it to the ventricle to pump out from the aorta.
the aorta branches into where? what does this supply?
it branches into the coronary arteries and supplies blood to the heart wall
what is a sinus? what is an example of one?
an open space , we have the coronary sinus where a pool of low pressure blood and flows to right atria.
valves help with what? what is the general name of the one between the atria and ventricles?
valves help with one way flow of blood within the heart and other vessels due to pressure differences. the general name of the valves in the heart are all atrioventricular (AV valve) between the atria and ventricles
the AV valve between the right chambers is called? the AV valve between the left is called?
right is called bicuspid or mitral valve while the left is called tricuspid valve.
what are the valves in between the aorta and pulmonary artery? what are they both called together?
the right side has the pulmonary valve and the aorta has the aortic semilunar valve. they are both known as semilunar valves.
do veins have valves? what does backflow of blood cause in veins?
yes they do, it causes varicose veins
the cardiac cycle is divided in two periods, name and define them.
diastole: ventricles are relaxed and atria are contracted
systole: ventricles contract causing AV valves to shut and the semilunar valves to open to allow blood flow to arteries, ventricles have low pressure here
how is the lub dub sound created? what occurs in lub and what occurs in dub?
it is produced by the valves shutting. lub occurs by closing of AV and dub occurs by semilunar valves closing
what is heart rate/pulse? what is avg HR
the number of times lub dub is repeated per min. avg HR is 45 bpm in athletes and 80 bpm in elders and kids
what is the stroke volume? the cardiac output (add formula)?
stroke volume is the amount of blood pumped with each systole. cardiac output is the total amount of blood pumped per min, formula is SV times HR
how can we increase cardiac output? what is this mechanism called and how do we do this
we increase CO by increasing HR and SV and this is the frank-starling mechanism: this occurs by stretching the heart muscle and filling it with blood, more blood in heart means more forcefully push increasing CO
how can we increase the blood coming into the heart
by increasing blood volume by retaining water and contracting large veins
how does cardiac muscle contract
muscle cells propagate AP through gap junctions by depol
what is the difference between neurons and cardiac cells
cardiac cells act as a functional syncytium: a tissue where cell cytoplasms are connected through gap junctions
where at the gap junctions found in the heart
intercalated disks, the connections by cardiac cells
why is AP delayed in the heart?
it is delayed as it passes through conduction system called the AV node to allow blood to fill the atria.
what channels do cardiac cells need to make AP?
they need fast and slow sodium channels and calcium channels. they allow longer depol
to make sure the AP gets communicated by all cells, what structure exists to help with this?
t tubules, that exist in skeletal muscle cells too
the heart contractions are controlled by what?
the sinoatrial (SA) node, the cells here are the pace makers of the heart
while neurons nor hormones cause heart contractions, what do they impact
contractibility of the heart (force of contraction)
what are the 3 phases that SA node goes through
phase 4: automatic slow depol caused by sodium leak channels
phase 0: upstroke of pacemaker potential, cells are brought up to threshold caused by influx of calcium
phase 3: repolarization caused by the closing of calcium channels and opening of potassium channels
what starts SA contractions FIRST, whats different about its RMP
sodium leak channels IMPORTANT, its RMP is unstable