ch 11 cardiac physiology Flashcards
1
Q
cardiovascular system
A
- blood (fluid that carries materials to and from cells)
- blood vessels (series of tubes)
- heart (pump)
- all cardiovascular systems, regardless of the organism, consist of these three basic components
2
Q
blood
A
- bld cells: erythrocytes (RBC) carry oxygen bound to hemoglobin, leukocytes (WBC) mediate immune responses, platelets (cell “fragments”) aid in blood clotting,
- plasma: liquid portion of bld
- if you donate plasma, it gets put in a tube and centrifuged until it separates into a clear yellow portion on top (plasma), and a red cellular portion on bottom
- plasma is mostly water, salts, and proteins (mostly antibodies)
- the the cellular portion: the vast majority of cells are RBC. they contain hemoglobin which has 4 iron molecules attached to it. whenever oxygen binds to the iron, it turns a deep red, which is where RBC get their color. oxidation is what causes rust (iron and oxygen + H2O = rust)
- WBC are in your immune cells which fight disease. they are not white, they are clear
- platelets are part of cells called megakaryocytes and they allow bld to clot
3
Q
blood vessels (vasculature)
A
- vessels transporting bld AWAY from the heart: arteries (big and AWAY), arterioles (small), arteries merge into arterioles, bld is moving very fast through these two vessels and once it reaches the capillaries it slows down drastically to allow enough time for exchange (through diffusion) to take place between the blood and the cells
- smaller diameter = slower speed
- capillaries (smallest/tiny diameter) which forces bld to move through as slowly as possible (this allows enough time for exchange to take place) bld leaving capillaries, on the way back to the heart, first flows into venules, then into veins (these are also wider diameter vessels for the same reason that arteries and arterioles are…speed)
- the only bld vessels that are “leaky” are capillaries bc these are needed for exchange. the rest are strictly for transport
- vessels transporting bld TO the heart: venules (small), veins (big)
4
Q
heart
A
- four chambers: left and right atria, left and right ventricles
- two separate pumps next to each other (separated by the septum (muscular wall) this is to keep oxygenated bld on the left side of the heart from mixing with deoxygenated bld on the right side of the heart
- deoxygenated bld is bld RETURNING from your tissues (this bld has dropped off oxygen to tissue cells and picked up CO2)(bld is low in oxygen and high in CO2)
- left heart (left atrium and left ventricle): supplies bld to systemic circuit (body)(oxygenated bld is pumped to body)
- right heart (right atrium and right ventricle) supplies bld to pulmonary circuit (lungs)
- right side pumps deoxygenated bld to the lungs (pulmonary circuit)
5
Q
anatomy of the heart
A
- deoxygenated bld will be colored blue for reference but its really a dark maroon/red
- veins through skin look blue but there is a layer of fat around the veins diffracting the light making them look blue
- oxygenated bld is bright red like a cherry
- the left ventricle is the most muscular bc it pumps bld the longest distance
- both atria only have to pump bld to the ventricles
- the right ventricle only has to pump bld to the lungs which are right next to the heart (not very far)
- the left ventricle pumps to the toes which is why its the most muscular
- the aorta is the largest bld vessel in the body
- the pulmonary artery is carried deoxygenated bld to the lungs so that it can be oxygenated and the aorta is carrying oxygenated bld to all of the body tissues
6
Q
PDA: patent ductus arteriosus
A
- ductus arteriosus is a duct that connects the aorta and the pulmonary artery in embryonic development. normally closes shortly after birth
- “patent” means “open.” in some individuals, this duct never closes, resulting in mixing oxygenated and deoxygenated bld. fairly common in premature babies
- leads to shortness of breath and stunted growth and can lead to congestive heart failure later in life
- when a baby is in the womb, it is not really using its lungs to breath, its receiving bld from the mother, which means the baby must rely on the mother to provide oxygen
- so there isnt any need for the pulmonary artery and aorta to be separated
- but just before birth , in a healthy baby, these vessels will blose off and be separted to prepare the baby for the use of its lungs (when this doesnt happen its called PDA)
7
Q
path of bld flow
A
- pulmonary circuit: bld vessels in lungs and bld vessels connecting lungs to heart
- systemic circuit: bld vessels in the rest of the body
- bld flows from pulmonary circuit to systemic circuit (circuits are in series)
- without the respiratory system, the circulatory system is useless and vice versa
- the respiratory system must constantly provide oxygen to the bld passing through the lungs in the pulmonary circuit. this oxygen gets transported to the cells in the body that are using the oxygen for cellular respiration
- these same cells are producing carbon dioxide (CO2)
- CO2 is a waste product, its toxic and was to be removed from the body
- this CO2 diffuses from the bld (pulmonary capillaries) to the lungs (alveoli), where it is exhaled
- again, deoxygenated bld is bld that has come back from the tissue cells and is low in oxygen and high in CO2 and oxygenated bld is bld leaving the left side of the heart and going TO the tissue cells. this bld is high in O2 and low in CO2
8
Q
heart valves
A
- opening and closing controlled by pressure differences between chambers
- allow unidirectional bld flow
- two sets: atrioventricular valves: separate atria and ventricles, mitral valve (left AV) and tricuspid valve (right AV)
- semilunar valves: separate ventricles and arteries, aortic semilunar valve (left SL) and pulmonary semilunar valve (right SL)
- simplest explanation for what valves do is that they prevent backflow of bld
- two AV valves prevent bld from leaving the ventricles and going back into the atria. the right AV valve separates the right atrium from the right ventricle (tricuspid valve)
- the left AV valve separates the left atrium from the left ventricle (bicuspid valve/ mitral valve)
- two semilunar valves (SL) prevent bld from leaving the arteries and going back into the ventricles.
- the pulmonary valve separates the left ventricle from the aorta
- bld moves from high pressure to low pressure (and/or its coming from an area of higher pressure to lower pressure) without valves, bld would constantly be moving back to where it came from as soon as the pressure gradient changes but valves keep that from happening
- two ways to increase pressure in the heart: add more bld bc more bld = more pressure OR contract. once a chamber in the heart is filled with bld, the only way to build pressure is for that chamber to contract
9
Q
how the AV valves work
A
- when pressure is higher in the atria than it is in the ventricles, these AV valves open and allow bld to flow to the ventricles. when pressure is higher in the ventricles, these valves close to prevent bld from moving back into the atria
- the papillary muscle contracts and pulls on the chordinae tendieae to keep the valves from turning inside out when pressure gets really high in the ventricles
10
Q
how SL valves work
A
- semilunar valves open when pressure is higher in the ventricles than it is in the aorta. these valves close as soon as the pressure gets higher in the aorta, to keep the bld from moving back into the ventricles
11
Q
series flow though pulmonary and systemic circuits
A
- left ventricle pumps bld through the aortic semilunar valve into aorta
- the left ventricle pumps oxygenated bld into the aorta, through the semilunar valve. this goes to all of your body cells
- the pressure is highest in the arteries: this bld came directly from the heart with nothing to slow it down
- bld in the veins is coming from capillaries, so its still trying to pick up speed (this is why cutting an artery is more dangerous than cutting a vein
- veins are the only bld vessels you can actually see through skin. arteries are much deeper
12
Q
bld flow through pulmonary and systemic circuits
A
- in the systemic circuit, oxygen diffuses from the blood into the tissue cells that are using this oxygen for cellular respiration. this means pressure for oxygen is higher in systemic capillaries than it is in tissue cells. CO2 being produced by these cells diffuses into the bld and makes it way back to the right side of the heart, so that it can be pumped to the lungs. this means that CO2 pressure is higher in the tissue cells than it is in the systemic capillaries.
13
Q
bld flow pt 2
A
the inferior vena cava carries deoxygenated bld from below the heart into the right atrium. the superior vena cava carries deoxygenated bld from above the heart into the right atrium. notice that there is no valve separating the vena cava from the right atrium. valves are used to prevent backflow of bld. there is no valve means that pressure in the vena cava must always be really high. so theres no danger of bld flowing from the right atrium to the vena cava
*think about putting a hose in the pool at full blast, water will not flow back up the hose bc the pressure is so high.
14
Q
bld flow pt 3
A
when pressure in the right atrium is higher than the right ventricle, the tricuspid valve opens and allows deoxygenated bld to flow into the right ventricle
15
Q
bld flow pt 4
A
when pressure in the right ventricle is higher than pressure in the pulmonary artery, the pulmonary semilunar valve opens and allows deoxygenated bld to flow into the pulmonary artery. this bld will be pumped to the lungs. where oxygen will diffuse from lungs to the bld and carbon dioxide will flow from the bld to the lungs
