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Physiology Test 2

The right and left AV valves are ___________ valves. cuspid
What is an identifying characteristic of cuspid valves? have flaps
The right AV valve has _____ cusps. 3 (tricuspid)
The left AV valve has _____ cusps. 2 (bicuspid)
What is another name for the bicuspid valve? mitral
What connects the cusps on the cuspid valves to the papillary muscles? cordae tendinae
What are the 2 purposes of the cordae tendinae on the cuspid valves? 1)attach the cusp/valve to the papillary muscles 2)anchor the valves closed, even against high pressure
How do the semilunar valves open and close? like the iris on a camera
What are the names of the R and L semilunar valves? R=pulmonary; L=aortic
What are the characteristics of skeletal muscle? striated, multinuclear
What are the characteristics of smooth muscle? non-striated, 1 central nucleus
What are the characteristics of cardiac muscle? quadrangular shape, striated, organized actin and myosin, single (oval-shaped) nucleus, heavily-banded lines hold fibers together
What is the name of the heavily-banded lines that hold cardiac muscle fibers together? intercollated discs
What is the purpose of the closely-bound nature of cardiac muscle? so that if one muscle fiber is stimulated, the stimulation can quickly propogate causing strong contraction
What do you call the interconnecting nature of cardiac muscle fibers? syncytial
What type of cardiac fiber initiates a signal? nodal
What are 2 examples of nodal cardiac fiber? SA node and AV node
What group of fibers is "the boss" when r/t heart beat? SA node (nodal fiber)
The origin of the heartbeat is (myogenic or neurogenic?) myogenic
What group of fibers acts as a gateway from atria to ventricles? AV node
Which type of cardiac fiber CANNOT hold a steady RMP? Why? nodal; b/c Na channels are leaky
What type of cardiac fiber conducts a signal? conductile
What are 2 examples of conductile cardiac fiber? internodal pathway, purkinjie fibers
What type of cardiac fibers are considered the "worker bees"? contractile
What type of fibers make up the majority of cardiac fibers? contractile
What types of cardiac fibers CAN hold a steady RMP? conductile and contractile
What accounts for the "plateau" after depolarization of conductile and contractile fibers? when Ca2+ channels open and Ca2+ influx occurs to activate the contractile mechanism, but b/c Ca2+ is +, it holds its depolarized state for a little while
Describe the pathway of a cardiac signal? originates in SA node --> internodal pathway --> AV node -->AV bundle --> L and R bundle branches --> purkinjie fibers
What are the stages of contractile action potential? 4=RMP; 0=depolarization; 2=plateau; 3=repolarization
In order to increase HR (cause more action potentials), the length of the plateau has to (lengthen or shorten?) shorten
In diastole ____________ pressure is slightly higher than ___________ pressure d/t blood coming in. atrial pressure > ventricular pressure
The first rise in atrial pressure is called the ____________. A wave
What happens the second that the ventricular pressure surpasses the atrial pressure? AV valve closes
The second rise in atrial pressure is called the ___________. C wave
What causes the C wave? the bowing of the valves due to high pressure below
Because the ventricles don't completely empty during systole, we start out with ~________mL in the ventricles. ~50mL
After a rapid passive inflow of blood, we reach _____________ when the maximum volume has passively poured in. diastasis
After diastasis, how do the ventricles get any more blood? atrial systole
After atrial systole, about how much blood do the ventricles have? ~120mL
What is defined as the rapid outflow of blood? systole
What is defined as "ventricle is contracting, but aortic valve is not opened yet, so no outflow of blood happens"? isovolumic contraction
What is defined as "ventricle is relaxed, but AV valve is not opened yet, so no inflow of blood happens"? isovolumic relaxation
Define LVEDV? left ventricular end diastolic volume= the volume of blood in the left ventricle at the end of ventricular diastole (~120mL)
What is another name for LVEDV? preload
Define LVESV? left ventricular end systolic volume= the volume of blood in the left ventricle at the end of systole (~50mL)
What is another name of LVESV? afterload
What is a typical stroke volume? ~70mL
What part of an EKG strip represents atrial depolarization? P wave
What part of an EKG strip represents ventricular depolarization? QRS complex
What part of an EKG strip represents ventricular repolarization? T wave
The sound S1(Lub) is the sound of what? AV valves closing
The sound S2(Dub) is the sound of what? aortic valve closing
What is the Frank-Starling Law? within physiological limits, the heart pumps all the blood that returns to it by way of the veins (the left ventricle knows how much of a contraction it should give due to how much blood it has)
Due to Frank Starling's Law, if the ventricles are holding more blood (LVEDV), it senses the need to have a (more or less?) powerful contraction? Why? more; because the pressure is higher, and the muscle fibers are more stretched
CO= ____ X _____ HR X SV
What is a standard HR? 70bpm
What is a typical CO? 4900 mL/min (SV=70mL; HR=70bpm)
As LVEDV/preload increases, CO (increases or decreases?) increases (to a point, at which the graph plateaus)
The _________ nerve has a parasympathetic cardiac branch that stretches to the SA node. vagus
The vagus nerve releases _________ to the external ___________ receptor in the SA node. ACh; muscarinic
The vagus nerve (hyper or hypo?)polarizes the SA node, (raises or lowers?) the RMP, and (increases or decreases?) HR? hypopolarizes the SA node, lowers RMP, decreases HR
The _____________ is considered to be the BRAKE of the heart. cardiac branch of the vagus nerve
Chronotropic effects of the heart refer to changes in ______. HR
What is an example of an agent that has a chronotropic effect on the heart? atropine
Inotropic effects of the heart refer to changes in _________. force of contraction
True or False: Ventricular depolarization and repolarization are in the same direction on the EKG. True (QRS and T wave are both above baseline)
True or False: If we could see both atrial depolarization and repolarization, they would be in the same direction on the EKG. False (P wave is above baseline, but atrial repolarization would be inverted)
Who discovered the first lead placement? Einthoven (Einthoven's triangle)
Describe Einthoven's lead I. Top of the triangle (R arm -, L arm +)
Describe Einthoven's lead II. R side of triangle (R arm -, R leg +)
Describe Einthoven's lead III. L side of triangle (L arm -, L leg +)
What is Einthoven's Law? The voltage (mV) in lead II is equal to the sum of the voltage of lead I + lead III (This is why lead II is the standard)
Describe the flow of signal from the AV node around the heart. AV node down septum to apex, back up to base, back down to apex (flows in 3D concentric circles)
Cardiac electrical current is a vector quantity. What does this mean? has magnitude and direction; means you can sum vector quantities (take all lines and combine into one)
The average angle of the vector of the cardiac electrical current is _________ degrees. 59
What is the angle of lead II? And why does is "get the best look at the current flow"? 60 degrees, because it is so close to 59 degrees, which is the average angle of the vector
True or False: Tachycardia can be physiologic or pathologic. True; physiologic(ex.exercise); pathologic (ex.MI with inc. HR to compensate for dec. SV)
True or False: Bradycardia can by physiologic or pathologic. True
Describe 1st degree heart block. prolonged PR interval; signal is getting conducted, just slower d/t more resistance
Describe 2nd degree heart block. block in the AV node, some signals can't get through
Describe 3rd degree heart block. total block in AV node; AV node becomes pacemaker
What is the most serious arrhythmia? ventricular fibrillation
What arrhythmia loses all normal/orchestrated parts of an EKG? ventricular fibrillation
What are 3 causes of v-fib? 1)enlarged heart, 2)overdose of sympathomimetic drugs (cocaine, amphetamines, etc), 3)electrocution (electricity passing through heart for >4sec)
What is the treatment for v-fib? defibrillation; passing a large current through the already fibrillating heart, which wipes out all electrical activity in hopes that normal signal will resume
Why would we give atropine to restart the heart? atropine stops all inhibitory mechanisms
Why would we give epi to restart the heart? epi stimulates the SA node to get a signal
Which vessels have a higher and more pulsatile pressure? Why? aorta, large arteries; they are closer to the pump
Which vessels have a lower and less pulsatile pressure? Why? arterioles, capillaries, veins; they are further from the pump
What are 2 ways the veins get blood back up to the heart despite gravity and without the pressure from the pump? 1)1 way valves; 2)skeletal muscle surrounding the vein that pumps blood back up to the heart when walking
If you lock your legs and no muscles are squeezing your veins to get blood back to the heart, you can lose up to ______% of venous return, causing you to pass out. 20%
Blood normally flows in a ____________ flow through the vessels. laminar
The (inner or outer?) most layer of blood flowing though the vessel is the slowest? and Why? outer-most; it has the most friction with the vessel wall
What are 3 things that can make our blood flow turbulently instead of laminarly? 1)when the flow is exceedingly fast, 2)when the blood meets an obstruction to flow, 3)when the blood flow is made to change directions at a sharp angle
What is a dangerous consequence of turbulent blood flow? clotting of the blood (ex. atherosclerosis narrows the lumen of the vessel; the narrow lumen can cause turbulent flow and the formation of a thrombus)
What is the formula for Poiseuille's Law? F= pi X deltaP X r4 /8nL (F=flow, delta P=pressure difference, r=radius, n=viscosity, L=length of vessel)
What properties of Poiseuille's law can increase the flow? increasing pressure difference, increasing radius, decreasing viscosity, decreasing length of vessel
How do you directly measure BP? insert a catheter into the artery
How do you indirectly measure BP? auscultatory or palpatory methods
What is the name of the sound heard during the auscultatory method of checking BP? karotkoff sound
When are the karotkoff sounds heard? at every systole once cuff is deflated to <systolic, until cuff is deflated <diastolic
How does the palpatory method of checking BP work? you can feel the blood hitting the vessel walls (turbulent flow from cuff obstruction)
As people age their systolic and diastolic pressures (increase or decrease?) increase
After age 40, we lose _____% of kidney function every decade. 10%
What are the 3 main determinants of BP? 1)cardiac output, 2)blood volume, 3) TPR (total peripheral resistance)
Cardiac output is directly related to (systolic or diastolic?) BP. systolic
Blood volume is directly related to (systolic or diastolic?) BP. diastolic
TPR is directly related to (systolic or diastolic?) BP. diastolic
True or False: TPR is the total sum of each blood vessel system (renal, hepatic, etc)? True
True or False: If any of the determinants of BP (CO, blood vol, TPR) increase, BP increases. True
What were the first line of drugs to treat HTN? direct vasodilators
How do direct vasodilators decrease BP? (which determinant of BP do they affect?) decreasing TPR
How do diuretics decrease BP? (which determinant of BP do they affect?) decreasing blood volume
How do beta blockers decrease BP? (which determinant of BP do they affect?) decreasing CO
Beta blockers only affect (systolic or diastolic?) BP. systolic (b/c decreases CO, which is directly related to systolic BP)
What makes up our rapidly acting homeostatic system for controlling BP? baroreceptors (pressure receptors)
Where are baroreceptors located? walls of the arteries
Which arteries have super concentrated areas of baroreceptors? arch of aorta and carotid bodies
How do baroreceptors control BP? if BP starts to increase, baroreceptors sense the stretch and fire a signal into the brain's cardiovascular centers
Once baroreceptors sense inc. BP and send a signal to the CV center of the brain, what 3 things happen? 1)inc. firing of the cardiac branch of vagus nerve to SA node,which dec.HR,which dec.CO), 2)dec. firing of sympathetic nerves to the heart(lowers BP by lowering CO), 3)dec. firing of sympathetic nerves to the arteries(lowers BP by decreasing TPR)
True or False: If baroreceptors are exposed to a chronically high pressure, they reset to see the higher pressure as the new "normal" True
What makes up our moderate-acting homeostatic system for controlling BP? renin-angiotensin-aldosterone system
How does the renin-angiotensin system increase BP when needed? kidneys release renin (hormone) which changes angiotensinogen into angiotensin I, which enters the lungs and comes in contact w/ ACE which converts it into angiotensin II (potent vasoconstrictor, inc. BP by inc. TPR)
How does aldosterone increase BP when needed? aldosterone pulls salt back into the blood (fluid follows), inc. BP by inc. blood volume
How do ACE inhibitors dec. BP? inhibit ACE enzyme (which converts angiotensin I into angiotensin II, preventing angiotensin II from causing vasoconstriction), which dec. BP
Beta blockers work (quickly or slowly?) compared to ACE inhibitors. quickly (b/c they act on the rapidly-acting homeostatic system and ACEI work on the moderate-acting homeostatic system)
Where is the long-acting homeostatic system located? kidneys
What is "compensated heart disease"? after myocardial ischemia, overtime, the healthy fibers will hypertrophy, which will increase CO, relieving the forward and backward pressures of the hypoeffective pump
What are "preferential capillaries"? loop around tissues; no gas exachange
What are "true capillaries"? where gas and nutrient exchange takes place
True or False: Your body decides which parts of your body need blood to its true capillaries at any specific time. True (ex. if you are sitting in class, your skeletal muscles don't need much blood flow, so blood may stay in your preferential capillaries around the skeletal muscles)
What are the 2 theories on the closing of the precapillary sphincters? 1) oxygen lack theory, 2) vasodilator theory
What is the oxygen lack theory of closure of precapillary sphincters? if cells are not metabolically active, the "spare" oxygen can be used to close the precapillary sphincters; if cells are metabolically active, there is no "spare" oxygen to constrict the sphincter
What is the vasodilator theory of closure of precapillary sphincters? when cells become metabolically active, you spill out metabolic waste products (lactic acid, ADP, adenosine, etc) and these waste products are natural vasodilators which tell the sphincters when to open/close
Blood is pushed out of the capillary into the interstitial space on the (arterial or venous?) end of the capillary. arterial (d/t the high hydrostatic pressure)
Fluid is pulled into the capillary on the (arterial or venous?) end venous (d/t the low hydrostatic pressure and the increased osmotic pressure)
True or False: All of the interstitial fluid is pulled into the capillary. False
True or False: Lymphatic capillaries pull some of the interstitial fluid into the lymphatic vessels as lymph. True (this prevents the accumulation of interstitial fluid-->edema)
How does lymph get back to the heart? via subclavian veins from all parts of the body
What cleans the lymph? neutrophils/monocytes
Why do lymph nodes swell during sickness? d/t increase in lymphocytes when there is an infection
What are some examples of vasoconstrictor agents? norepi, epi, angiotensin II, vasopressin/antidiuretic hormone, increase in Ca2+ ion
What are some examples of vasodilator agents? bradykinin, histamine, increase in K+ ion, increase in Mag ion, increase in CO2