Term
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Definition
-C.O. or Q is the blood volume pumped per minute by each ventricle (left and right)
-C.O. or Q = cardiac rate x stroke volume |
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Term
| the sequence by which the heart pumps blood out of it |
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Definition
| Contraction --> ↑ force --> (P = F/A) --> ↑ P --> ↑ ∆P difference (gradient) between 2 ends --> ↑ stroke volume |
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Term
| how to calculate cardiac output (C.O. or Q) |
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Definition
C.O. or Q (ml/min) = cardiac rate (beats/min) x stroke vol (ml/beat)
[image] |
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Term
| the cardiac output and other cardiac details at rest |
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Definition
-~70 beats/min, stroke vol ~80 ml/beat ~5,600 ml Q /min
-Total blood vol ~ 5,600 ml
-each ventricle pumps the equivalent of the total blood volume each minute |
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Term
| how the cardiac output is affected by other things in the body |
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Definition
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Term
| Chronotropic (time, frequency) effect |
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Definition
| autonomic (sym & parasym) on SA node is the main controller of cardiac rate |
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Term
| how the Chronotropic (time, frequency) effect regulates cardiac rate |
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Definition
-Original rhythm set by SA node (auto-rhythmic cells)
-Symp and parasymp nerve fibers modify rate of spontaneous depolarization and conduction rate on auto-rhythmic cells
+Symp – stimulatory; parasymp – inhibitory
-The actual pace set by SA node depends on the net effect of antagonistic influences of symp + parasymp |
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Term
| what drives the heart rate? |
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Definition
| Without neuronal influences, SA node will drive heart rate at its spontaneous activity |
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Term
| The activity of autonomic innervation of the heart is coordinated by... |
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Definition
| cardiac control centers in the medulla oblongata (vital centers) |
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Term
| how the sympathetic (NE & E) part of the ANS controls heart rate |
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Definition
| ↑ Na+ & Ca2+ channels open --> “+” inotropic effect --> ↑ strength of contraction (contractility) in heart
-↑ rate of firing in SA node
-↑ conduction rate
-↑ strength of contraction
[image] |
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Term
| how the parasympathetic (ACh) part of the ANS controls heart rate |
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Definition
| hyperpolarizes SA node --> allows K+ channels open longer --> “-” inotropic effect in atria, NOT in ventricle
[image] |
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Term
| table summarizing the sympathetic and parasympathetic effects of the ANS on different regions of the heart |
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Definition
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Term
| Factors affecting stroke volume |
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Definition
-contractility (strength of contraction)
-end-diastolic volume (EDV)
-total peripheral resistance (TPR) |
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Term
| end-diastolic volume (EDV) (preload) |
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Definition
vol of blood in ventricles at the end of diastole (end of relaxation); depends on (proportional to) contractility
-↑ in contractility --> ↑ in stroke vol
-↑ of EDV --> ↑ in stroke vol |
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Term
| total peripheral resistance (TPR) |
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Definition
frictional resistance or impedance to blood flow in arteries
-↑ of TPR --> ↓ in stroke vol |
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Term
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Definition
SV / EDV
-normally is 60-70% (about 2/3 of blood out of ventricle each contraction) at rest
-larger fraction during exercise |
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Term
| how contractility is regulated extrinsically |
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Definition
| Sympathoadrenal system – NE, E --> “+” inotropic effect (more Ca2+ available to sarcomeres) --> ↑ contractility |
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Term
| how contractility is regulated intrinsically (Frank-Starling law of heart) |
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Definition
-Varying degree of stretching of myocardium by EDV
-↑ EDV --> ↑ in myocardial stretching --> the actin filaments overlap with the myosin only at the edges of the A band --> ↑ # of interactions between actin and myosin --> ↑ in contractility (contracts more forcefully)
-↑ EDV --> ↑ cardiac contractility --> ↑ Q
[image] |
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Term
| Frank-Starling law of heart |
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Definition
how contractility is regulated intrinsically
-Varying degree of stretching of myocardium by EDV
-↑ EDV --> ↑ in myocardial stretching --> the actin filaments overlap with the myosin only at the edges of the A band --> ↑ # of interactions between actin and myosin --> ↑ in contractility (contracts more forcefully)
-↑ EDV --> ↑ cardiac contractility --> ↑ Q
[image] |
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Term
| how sympathetic NS (NE, E) affects cardiac output (Q) |
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Definition
-“+” chronotropic effect on cardiac rate (C.R.)
-“+” inotropic effect on contractility (contraction strength) |
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Term
| how parasympathetic NS (ACh) affects cardiac output (Q) |
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Definition
-“–” chronotropic effect on cardiac rate (C.R.)
-No direct effect on contractility in ventricles |
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Term
| some factors affecting stroke volume |
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Definition
-End-diastolic volume (EDV)
-total peripheral resistance (TPR)
-contractility (strength of contraction) |
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Term
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Definition
-Return of blood to heart via veins, driven by venous pressure.
-Veins have thinner walls, hold ~60-70% of blood in the body (capacitance vessels) vs. arteries (resistance vessels) |
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Term
| how venous return (VR) affects end-diastolic volume (EDV) |
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Definition
they return blood to heart via veins, driven by venous pressure
↑ VR --> ↑ EDV --> (Frank-Starling law of heart) --> ↑ Q |
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Term
| venous return (VR) is affected by... |
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Definition
-total blood volume
-venous pressure
-breathing
-intrathoracic pressure
[image] |
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Term
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Definition
veins
-they have lots of capacity; they hold about 70% of the blood |
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Term
| why veins have thinner walls than arteries do |
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Definition
| because veins have a lot less smooth muscle |
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Term
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Definition
arteries
-they have a natural tone caused by the smooth muscle such that the diameter is limited such that they create vascular resistance |
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Term
| venous pressure affected by... |
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Definition
-↑ Sympathetic activity --> ↑ venous constriction --> ↑ VR
-↑ Skeletal muscle pumps ↑ increase VR
[image]
[image] |
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Term
| how breathing affects venous return |
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Definition
P difference between the thoracic and abdominal cavities
-During inspiration, ↓ in thoracic P or ↑ in abdominal P --> ↑ P gradient --> ↑ VR |
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Term
| how water is distributed in the body |
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Definition
about 45 liters in an adult human
-Intracellular compartment – 2/3 of total body H2O
-Extracellular compartment – 1/3 total body H2O – 80% interstitial fluid, 20% blood plasma
[image] |
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Term
| Exchange of fluid between ______, between ______ is in state of dynamic equilibrium |
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Definition
ICF and ECF
interstitial fluid and blood plasma |
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Term
| Exit of blood plasma into the interstitium at the ______ end of the capillary and mostly returned from the ______ end of the capillary |
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Definition
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Term
| hydrostatic pressure of plasma |
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Definition
-due to heart pumping + gravity
-exerted against capillary wall
-Is the main P drives fluid out --> ↑ formation of interstitial fluid (IF)
-promotes formation of tissue fluid
-net filtration pressure = hydrostatic pressure in capillary (17-37 mmHg)-- hydrostatic pressure of ECF |
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Term
| depiction of how and where fluid goes in and out of the capillaries |
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Definition
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Term
| which hydrostatic pressure involving the capillary is higher? that of plasma or that of insterstitial fluid? |
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Definition
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Term
| Colloid osmotic (oncotic) pressure |
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Definition
exerted by proteins in fluid
-Colloid osmotic P in blood plasma = 25 mm Hg (high)
-Colloid osmotic P in IF = 0 mm Hg
-Plasma colloid osmotic P is the main P to retain fluid in b.v. |
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Term
| how the movement of fluid occurs during exchange of fluid between capillaries and interstitial fluid |
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Definition
Fluid movement = fluid out - fluid in = (Pc + pi) - (Pi + pp)
-Pc = hydrostatic P of blood (37 mmHg)
-Pi = hydrostatic P of interstitial fluid (IF) (1)
-πp = colloid osmotic P of plasma (25)
+Promotes fluid re-absorption into circulatory system
-πi = colloid osmotic P of IF (0)
[image] |
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Term
| how the movement of solutes occurs during exchange of fluid between capillaries and interstitial fluid |
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Definition
-Glu., salts, ions, etc. are filtered along with water
-Very little plasma proteins is in IF (0 mm Hg)
-At the arteriolar end of capillary: (37+0) - (1+25) = 11 mm Hg
-At the venular end of capillary : (17+0) - (1+25) = -9 mm Hg
[image] |
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Term
| Excess IF returned to venous system by... |
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Definition
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Term
| some ways proper ECF levels are maintained |
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Definition
| filtration, osmotic reuptake, and lymphatic drainage maintain proper ECF levels |
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Term
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Definition
| excessive accumulation of tissue fluid |
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Term
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Definition
-High arterial blood pressure (hydrostatic pressure of blood, pushing more fluid out of capillaries)
-Venous obstruction (may cause more fluid to exit capillaries)
-Decreased plasma proteins (liver or kidney diseases) --> ↓ colloid osmotic pressure of blood plasma
-Leakage of plasma proteins into tissue fluid (↑ πi)
-Obstruction of lymphatic drainage
-Myxedema due to hypothyroidism (production of mucin in interstitial fluid, an inflammatory status) |
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Term
| the most important organ for regulating body fluid |
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Definition
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Term
| Volume of urine excreted can be adjusted according to... |
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Definition
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Term
| some hormones that regulate urination |
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Definition
| -Antidiuretic hormone (ADH, vasopressin; can increase blood pressure)
-Renin-angiotensin-aldosterone (RAAS) system
+Aldosterone – ↑ retention of Na+ (main) & water --> ↑ blood volume
-Atrial natriuretic peptide (ANP, ANH) |
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Term
| how the renin-angiotensin-aldosterone (RAAS) system affects urination |
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Definition
| Aldosterone – ↑ retention of Na+ (main) & water --> ↑ blood volume |
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Term
| how ADH is involved in regulating blood volume |
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Definition
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Term
| how dehydration causes thirst |
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Definition
Dehydration --> ↑ blood plasma osmolality --> activate osmoreceptors in hypothalamus:
-↑ Secretion of antidiuretic hormone (ADH, vasopressin) from posterior pituitary --> ↑ retention of water by kidney --> ↓ blood plasma osmolality and ↑ maintain the blood volume |
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Term
| ADH release is inhibited by... |
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Definition
`low blood plasma osmolality
[image] |
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Term
| hoe the Renin-angiotensin-aldosterone (RAA) system regulates blood volume |
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Definition
-↓ in blood flow through the kidneys --> ↑ renin secretion --> activates the RAS system --> ... --> ↑ angiotensin II
-Angiotensin II is a powerful vasoconstrictor
-↑ Angiotensin II --> ↑ aldosterone
-Stimulates thirst
[image] |
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Term
| how aldosterone regulates blood volume |
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Definition
| -A steroid H secreted by adrenal cortex
-Release stimulated by salt deprivation, low blood volume, low BP
-↑ Retention of Na+ & water --> indirectly ↑ blood volume
-Does not alter plasma osmolality |
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Term
| how the atrium functions as an endocrine tissue |
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Definition
↑ Blood volume --> detected by stretch receptors in left atrium --> ↑ release of atrial natriuretic peptide (ANP)
[image] |
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Term
| the effect of atrial natriuretic peptide (ANP) on blood volume |
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Definition
-↓ Aldosterone secretion --> ↑ salt and water excretion from urine --> ↑ blood volume, called natriuresis (increased Na+ excretion)
-↑ Vasodilation --> ↑ fluid flow from blood to interstitium --> ↓ blood volume
[image] |
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Term
| meaning of the word natriuresis |
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Definition
| "Natri" means sodium. "Uresis" means increased urine volume |
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Term
| how atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) work together to regulate blood volume |
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Definition
↑ ANP together with ↓ ADH --> acts in a negative feedback system --> ↓ blood volume
[image] |
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Term
| general overview of what regulates blood volume and cardiac output and such |
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Definition
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Term
| the 2 factors affecting cardiac output |
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Definition
-stroke volume
-cardiac rate |
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Term
| ______ determines how much blood flows through a tissue or organ |
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Definition
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Term
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Definition
| Vasodilation --> ↓ vascular resistance --> ↑ blood flow |
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Term
| effects of vasoconstriction |
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Definition
| Vasoconstriction --> ↑ vascular resistance --> ↓ blood flow |
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Term
| the flow of blood through the vascular system is due to... |
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Definition
| the pressure gradient at the 2 ends (ΔP) |
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Term
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Definition
| vascular resistance ∝ Lη / r4
BF ∝ ΔP / R
L = length of vessel
η = viscosity of blood (anemia → ↓ η)
r = radius of vessel (mm), vasoconstriction vs. vasodilation
BF = blood flow
P = pressure
R = resistance |
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Term
| how the sympathetic nervous system (main regulator) affects blood flow |
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Definition
↑ Q (C.O.) & ↑ total peripheral resistance (TPR)
-α-Adrenergic stimulation --> vasoconstriction (the dominant sympathetic effect in the body)
-Cholinergic sympathetic & β-adrenergic stimulation – vasodilation of skeletal muscles (fight or flight, minor effect)
-Overall (combined α- & β- adrenergic) --> ↑ TPR
-Exercise or anger --> ↑ TPR but ↑ cardiac inotropy & chronotropy --> ↑ SV --> ↑ Q |
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Term
| how the parasympathetic nervous system (rest and digest/repair) affects blood flow |
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Definition
-Vasodilation in GI, salivary gland & external genitalia
-only minor effect on TPR |
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Term
| how the endocrine system regulates blood flow |
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Definition
-Angiotensin II – vasoconstriction
-ADH (functions as vasopressin at high concentration) – vasoconstriction |
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Term
| how paracrine regulation regulates blood flow |
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Definition
| the endothelium secretes the vasoconstrictor endothelin-1 and the vasodilator NO |
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Term
| Endothelial nitric oxide synthase (eNOS) |
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Definition
produces NO from L-arginine
-present in arteries |
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Term
| how NO is made and used for vasodilation |
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Definition
| -Endothelial nitric oxide synthase (eNOS) of arteries produces NO from L-arginine
-NO diffuses to vascular smooth muscles --> activates guanylate cyclase --> ↑ cGMP --> ↓ cytoplasmic [Ca+2] --> smooth muscle relaxation --> vasodilation
-Binds to hemoglobin in RBC --> released to tissues with low PO2 --> vasodilation
-Medicine to treat angina pectoris (eg. nitroglycerin) --> convert to NO |
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Term
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Definition
| lack of oxygen to a certain area, possibly pectoralis, due to insufficient blood flow |
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Term
| the 2 types of intrinsic regulation of blood flow |
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Definition
-myogenic control
-metabolic control |
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Term
| Myogenic control of blood flow |
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Definition
-autoregulation allows constant cerebral blood flow
-↓ in systemic arterial P --> vasodilation of cerebral vessels
-↑ in systemic arterial pressure --> vasoconstriction of cerebral vessels --> protect finer vessels downstream from the elevated P; this protects against stroke
[image]
MAP = mean arterial blood pressure |
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Term
| Metabolic control of blood flow |
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Definition
| -local effects on cerebral & skeletal muscle vessels
-↑ in metabolic activities --> ↓ O2 --> vasodilation
-↑ in metabolic activities --> ↑ CO2 --> vasodilation
-↑ in metabolic activities --> ↓ pH due to CO2, lactate --> vasodilation
-Release of adenosine or K+ from the tissue cells --> vasodilation
-in summary, this seems to be where the partial pressures of oxygen and carbon dioxide determine the amounts of blood flow needed
[image]
MAP = mean arterial blood pressure |
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Term
| the pressure and area for different vessel types in the circulatory system |
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Definition
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Term
| capillaries are narrow, but their blood pressure is reduced because of... |
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Definition
| the total cross-sectional area |
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Term
| why arterioles tend to have the highest vascular resistance |
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Definition
| Arterioles are rich in smooth muscle --> the smallest diameter --> the greatest resistance |
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Term
| how kidneys regulate blood pressure |
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Definition
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Term
| how the sympathetic nervous system / sympathoadrenal system regulates blood pressure |
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Definition
| by epinephrine and norepinephrine as neurotransmitters |
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Term
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Definition
stretch receptors in aortic arch and carotid sinuses that detect BP change
-More sensitive to ↓ in BP and sudden changes in BP
[image] |
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Term
| how the regulates blood pressure baroceptor reflex |
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Definition
-More sensitive to ↓ in BP and sudden changes in BP
-example: A change from lying to upright posture --> ↓ BP --> detected by baroreceptors in aortic arch & carotid sinus --> info sent to medulla --> ↓ parasympathetic and ↑ sympathetic activities --> vasoconstriction and ↑ cardiac rate --> ↑ BP
[image] |
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Term
| 2 types of reflexes that regulate blood pressure |
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Definition
-baroceptor reflex
-atrial stretch reflex |
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Term
| how the atrial stretch reflex regulates blood pressure |
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Definition
when ↑ venous return -->
-pathway 1: Thru vagus nerve --> posterior pituitary --> ↓ ADH secretion --> ↑ urine vol --> ↓ blood vol --> ↓ BP
-pathway 2 (the pathway illustrated below): ↓ Renin --> ↓ angiotensin II --> natriuresis --> ↑ urine vol --> ↓ blood vol --> ↓ BP
-Stimulates ↑ atrial natriuretic peptide (ANP) secretion --> natriuresis --> ↑ urine vol --> ↓ blood vol --> ↓ BP
-↑ ANP secretion --> vasodilation --> ↓ TPR --> ↓ BP
[image] |
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Term
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Definition
device that goes around your arm to measure blood pressure
[image] |
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Term
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Definition
| flow of blood through vessels that are nor compressed |
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Term
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Definition
| sound blood makes in turbulent flow through compressed brachial artery |
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Term
| how blood pressure is measured with a sphygmonometer |
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Definition
-A P cuff is inflated, then deflated slowly
-The first sound of Korotkoff, caused by a constriction in the artery, occurs when the cuff P equals the systolic P. This is the systolic blood pressure.
-The last sound of Korotkoff is heard when the cuff P equals the diastolic ABP. This is the diastolic blood pressure.
[image] |
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Term
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Definition
| Pulse pressure = systolic P – diastolic P |
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Term
| mean arterial (blood) pressure |
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Definition
-Mean ABP = diastolic P + 1/3 pulse P
-Represents the average arterial pressure during the cardiac cycle
-(Mean ABP – VBP) is the force to drive blood through capillary beds of organs |
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Term
| why meaqn ABP = diastolic P + 1/3 pulse P |
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Definition
| because diastole accounts for about 0.5 seconds and systole accounts for about 0.3 seconds |
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Term
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Definition
|
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Term
| some things that may cause high blood pressure |
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Definition
-increased blood volume
-increased cardiac output
-increased total peripheral resistance
-diseases |
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Term
| some dangers of hypertension |
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Definition
-cerebral stroke
-atherosclerosis (due to too much friction in blood vessels)
-↑ cardiac workload |
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Term
| some treatments for hypertension |
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Definition
| -angiotensin converting enzyme (ACE) inhibitors (reduce vasoconstriction)
-β-blockers
-Ca2+ channel blockers (reduce contractility of heart)
-diuretics (increased urine volume) |
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Term
| why angiotensin converting enzyme (ACE) inhibitors can be used to lower blood pressure |
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Definition
because ACE converts inactive angiotensin I into active angiotensin II, which causes vasoconstriction
[image] |
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Term
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Definition
| caused by sudden blood loss
-low blood volume --> low blood pressure --> inadequate delivery of blood/O2 to organs --> cannot be compensated --> progress to an irreversible state |
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