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Physio1 Exam2

Define Frank Starling Law Volume of blood ejected by the ventricle is dependent upon the volume present at the end of diastole **volume the heart ejects in systole equals the volume it receives in venous return
Preload? Depends upon the LV end diastolic volume (EDV)
Afterload? Depends upon aortic pressure
Stroke volume and cardiac output correlate directly with? End diastolic volume
End diastolic volume correlate directly with? Venous return
IsoVol-R? Drop in pressure but not in volume
IsoVol-C? Heart contracts but valve is still closed
Vent Eject? High pressure, decreased volume in ventricle
What are the two components to CARDIAC MINUTE WORK? Volume work and pressure work
Pressure work? Cardiac output x aortic pressure
Myocardial oxygen? Pressure work is far most costly than volume work
What is the driving force for blood flow? Mean arterial pressure (Pa)
Positive chronotropic? Increase in heart rate
Negative chronotropic? Decrease in heart rate
Equation for Pa (mean arterial pressure)? Cardiac output x TPR
What are the regulatory mechanisms for Pz? Baroreceptor reflex, Renin angiotensin system
Mechanoreceptors? Sensitive to stretch and pressure
Where are mechanoreceptors located? Carotid sinus and aortic arch
What are mechanoreceptors more sensitive too? Change in pressure and RAPID change in arterial pressure
What is activated in Cushing reaction? Central chemoreceptors
What happens in cushing reaction? Intense vasoconstriction in the body to direct blood from to the brain
Microcirculation? Blood flow in capillaries
Autoregulation of blood flow is done by? Vasoconstriction and vasodialation (local blood flow control)
Active hypermeia? Increase in blood flow to an organ that has increased metabolic demand(local blood flow control)
Reactive hypermeia? If a body tissue is without 02 then the body will repay the O2 debt(local blood flow control)
Myogenic hypothesis? Explains autoregulation. When vascular smooth muscle is stretched, it contracts
Metabolic hypothesis? Explains local control of blood flow. Alters resistance of the arterioles so that O2 delivery to a tissue can be matched to P2 consumption of the tissue
Examples of vasodilator metabolites? Lactate, CO2, H, K, adenosine
What are vasodilator metabolites found? Metabolic hypothesis
Peripheral chemoreceptors? O2 decreases->activates sympathetic->arteriolar vasoconstriction and increase in parasympathetic outflow to the heart and produces decreased heart rate
Central chemoreceptors? Sensitive to PCO2 and Ph->increase in sympathetic activity
The carotid sinus baroreceptors are responsive to what kinds of pressure? An increase OR a decrease
The aortic arch baroreceptors are responsive to what kinds of pressure? Primarily to an INCREASE
T/F: Baroreceptors are mechanoreceptors? True
The baroreceptors effect the parasympathetic by? Vagus N on the SAnode to decrease heart rate
The baroreceptors effect the sympathetic by 4 things? (1) effect on SAnode to INCREASE heart rate (2) effect on cardiac muscle to INCREASE contractility and stroke volume (3) effect on arterioles to produce vasoconstriction and INCREASE TPR (4) effect veins to produce venoconstriction and dec unstressed vol
Hemorrhage produces a decrease in Pa bc? As blood volume decreases, stressed volume also decreases
Baroreceptor in response to hemorrhage does what? Decrease in Pa->decreased stretch on baroreceptor->decreased firing rate of the carotid sinus N
Give examples of vasoactive substances? Histamine, bradykinin, serotonin
Prostaglandins (PGE) produce? Vasodilation
Thromboxane A2 produce? Vasoconstriction **From platelts
Angiotensin II and Vasopression produce? Vasoconstrictiors
Atrial natriuretic peptide does what? Is secreted in atria in response to increase arterial pressure and causes vasodilation *Promotes Na EXCRETION**
The first heart sound is made from what? Closure of the AV valves
The second heart sound is made from what? The aortic valve closes slightly before the pulmonic valve
Barorecptors are located in what two places? Carotid sinus and aortic arch
Renin converts ____ to _____ Angiotensinogen to angiotensin I
Signals from the barorecptors report to the ___ NTS - Medulla
Function of aldosterone is to reabsorb ___ ions? NA
ADH acts on 2 receptors that are responsible for ___ and ___ Vasoconstriction and increase water permeability
Examples of vasodialator metabolite is CO2, lactate, histamine, H, K
In response to high blood pressure, there is a __ in parasympathetic activity and a ___ in sympathetic activity Increase in para and a decrease in symp
What enzyme converts AngI to AngII ACE
When myogenic muscle stretches, it? Contracts
What hormone promotes NA secretion? AMP *
Starling forces that promote filtration? Pc & pie-i
What side of the heart carries O2 blood? Left
What side of the heart carries DeO2 blood? Right
Majority of the arteries like the aorta carry 02 blood EXCEPT the? Pulmonary A, it carries De02 blood
Majority of the veins like the vena cava carry De02 blood EXCEPT the? Pulmonary V, it carries 02 blood
What valves are located on the L side of heart? Mitral valve
What valves are located on the R side of heart? Tricuspid valve
Define cardiac output? Amount of blood that is pumped into circulation(body) per min
How much blood is pumped per min in body? 5L per min
What are the three mechanisms for blood flow change? (1) cardiac output remains constant but blood flow is redistributed (2)cardiac output increase or decreases and blood flow among the organs is kept constant (3)combination of the two above
Blood that comes back to the heart is none as? Venous return
Blood in the arteries is known as? Why? Stressed volume. Because the heart pumps blood into the arteries
What do arteries have more of than veins? Arteries have more elastic tissue and they are thick walled
Veins have the ability to? Stretch and pool blood
Blood in the veins is known as? Unstressed volume
Where does gas exchange take place? In capillaries
Alpha1 and beta2 are what kind of receptors? Sympathetic. Known as Adenergic receptors
Adenergic receptors are ? what do they respond to? Alpha 1 & beta 2. They respond to adrenaline
What does alpha 1 do? Constriction
What does beta 2 do? Dilate
Capillaries have the biggest? Surface area but little blood
Veins have more? Blood bc thin walled, less elastic tissue, giving them the ability to have more compliance
Blood always flows from? High pressure to low pressure
If you increase resistance, what happens to blood flow? Decreases (vasoconstriction)
If you decrease resistance, what happens to blood flow? Increase (vasodilation)
Define laminar blood flow? Velocity on side of blood vessels is zero. Max velocity in the center
Normal blood pressure? 120/80
How to find MAP (mean arterial pressure)? Diastolic+ 1/3 of pulse pressure
What is pulse pressure? Systolic-diastolic
Heart spends most of its time in? diastolic (relaxation)
Where is the largest drop in blood pressure? In the arterioles
Define contractile cells ? Majority of atria and ventricular tissues and are the working cells of the heart. GENERATE ATP
Define conducting cells? Constitute the tissues of the SA/AV node. They don't contribute to generation of force but more to rapidly spread action potentials over the entire myocardium
Who is the pacemaker of the heart? SA node- the SAnode has the ability to generate action potentials by itself without and neuro input from the brain
What are the two kinds of pacemakers? Temporary and permeant
Define Frank Starling Law? Length tension relationship. The more the heart stretches, the more it will contract
The pacemaker is a collection of? Conducting cells
What does the heart use for energy? Fats
Define overdrive suppressing? SA node take the lead by suppressing the other pacemakers
Define ectopic pacemaker? Latent pacemaker can take over if SA node is suppressed
Does SA node have a plateau? No
Does ventricle have a plateau? Yes
What kind of cell is SAnode? Conducting
What kind of cell is ventricle? Contractile
What kind of membrane potential does the SA node have? UNstable resting membrane potential
What kind of membrane potential does the Ventricles have? Stable resting membrane potential
What type of Ca channels does SA node have? T type Ca channels
What type of Ca channels does the ventricles have? L type Ca channels
Where is the AP from in SAnode? Action potential made by itself
Where is the AP from in the ventricles? Needs an AP from the SAnode
Beta1 receptors deliver? POSITIVE chronotropic effects
Muscarinic receptors deliver? NEGATIVE chronotropic effects
Chronotropic=? Heart rate
Ionotropic=? Contraction
Dromotroic=? Conduction velocity
What are the parasympathetic receptors? alpha1, alpha 2, beta1, beta 2
What are the sympathetic receptors? Nicotinic, muscarinic M2
Conduction velocity depends on? The size of inward current and the upstroke of the action potential
Define heart block? Conduction velocity via the AV node is sufficient decreased. AP maybe not be conducted at all or insufficiently conducted from atria to ventricles
IN the sympathetics, what effects the contraction of the heart? Beta receptors
In parasympathetics, what effects the contraction of the heart? Muscarinic receptors only on the ATRIA
What do muscarinic receptors on the atria do? Decrease I-Ca and increase in I-K outward current
Increase heart rate=? Increase contractility
Define stroke volume? Volume of blood ejected per beat (70mL) EDV-ESV
Define ejection fraction? Fraction of end diastolic volume ejected in each stroke volume (55%) SV/EDV *Indicator of contractility
Define Cardiac output? Total volume ejected by the ventricle per unit time SVxHR
Define EDB? Amount of blood in the ventricles before ejection
Define ESV? Amount of blood in the ventricles after ejection
Define cardiopulmonary low pressure baroreceptors? Veins, atria, pulmonary arteries-detect changes in the blood volume and return blood volume to normal
Define bainbridge relfex Pressure atrial or venal receptors are activated by increase in pressure that sends info to the nucleus tractus solitarius in the medulla to increase in renal perfusion and finally increase in Na and water excretion
Lymphatic capillaries lie in the? in the interstitial fluid and possess one way flaps
What are the two mechanisms for blood flow? Local control and nerual/hormonal control
Coronary is controlled by? Mostly local metabolite such as hypoxia (increase in O2 demand) and adenosine (vasodialtion) *reactive hyperemia
Cerebral is controlled by? Controlled by local metabolites such as increase in CO2 cause vasodilation of the cerebral arteries
Control of skeletal? Both local metabolites (lactate, K) and sympathetic innervation (alpha 1, beta 2) *reactive hyperemia
Control of skin? Dense sympathetic innervation, very little role of local metabolites, only during trauma
Temp regulation of heat generation? Thyroid hormones, sympathetic nervous system, shivering, behavioral
Temp regulation of heat dissipation? Decrease sympathetic activity in the skin blood vessels but increase activity of sympathetic cholinergic fibers (sweating), shunting of blood in veins, behavioral
Define heat exhaustion? Occurs in response to elevated environmental temp and can result from excessive sweating
Define heat stroke? Sweating does NOT occur and body temp increases to the point of tissue damage
Created by: wizdumbslp