SI Session Cardiac flow, output and blood pressure Spring 2010 For Dr. Wright’s Bio 6 Class Designed by Pyeongsug Kim ©2010 Picture from

Cardiac flow, output and blood pressure What is cardiac output and how is it calculated? (so know stroke volume and cardiac rate) How do autonomic nerves regulate heart activity? (sympathetic and parasympathetic) What events might increase venous return? How would increased venous return influence cardiac output? What is edema and what causes it? How might the following affect blood volume (increase or decrease) (note: refer to physiology of kidney) High protein concentration in blood plasma Secretion of ADH Renin-angiotensin-aldosterone ANF (atrial natriuretic factor) How would vasodilation or vasoconstriction affect blood flow? What is an intrinsic or extrinsic factor that contributes to each? Give an example of how vasoconstriction can occur in one part of the body and vasodilation in another. What sorts of events might reduce coronary blood flow? What are variables that affect blood pressure? How is blood pressure measured? What is the significance of pulse pressure? Mean arterial pressure? What compensations are performed by the body when blood pressure drops? What compensations are performed when congestive heart failure occurs? What are some drugs that are used to treat congestive heart failure and how do they work

Designed by Pyeongsug Kim, ©2010 _______________ :Is volume of blood pumped/min by each ventricle _______________ :blood pumped/beat by each ventricle Cardiac Output (CO) Stroke volume (SV) CO = SV x HR

Designed by Pyeongsug Kim, ©2010

pumped/min. ________________ is volume of blood pumped/min. by each ventricle.(Equivalent to the total blood volume) pumped/beat ________________ is volume of blood pumped/beat by each ventricle. SV and HR are regulated by ___________. What is cardiac output and how is it calculated? (so know stroke volume and cardiac rate) Cardiac Output (CO) Stroke volume (SV) Cardiac Output = ANS system Stroke volume x Heart Rate CO = SV X HR Designed by Pyeongsug Kim, ©2010

↓HR by __________  Opens ____ channels  Designed by Pyeongsug Kim, ©2010 Normally Symp. and Parasymp. activity influence (SV/HR). ↑HR by ____________.  Opens _____& _____ channels  Symp.(NE, Epi) Parasymp.(ACh) The heart’s rhythm is set by the rate of spontaneous depolarization in the ________. (Autonomic innervation of SA node is main controller of HR.) SA Node Na+ Ca++ K+ Cardiac control center of __________________ this activity of autonomic innervation medulla oblongata depolarization Hyperpolarization

Normally Symp. and Parasymp. activity influence (SV/HR). The heart’s rhythm is set by the rate of spontaneous depolarization in the ________. ( Autonomic innervation of SA node is main controller of HR.) Spontaneous depolarization is known as __________. SA Node pacemaker HR is increased by _____________. - stimulate opening of ____ and ____ channels.  HR is decreased by _____________ -ACh promotes opening of ____  Symp.(NE, Epi) Parasymp.(Ach) Na+ Ca++ K+ Cardiac control center of __________________ this activity of autonomic innervation medulla oblongata depolarization Hyperpolarization Designed by Pyeongsug Kim, ©2010

Venous Return(VR) VR Controls EDV and thus SV and CO - Strength of ventricular contraction increased as EDV increases. CO -↑VR  (↑ / ↓)EDV  ( ↑ / ↓ )SV  ( ↑ / ↓ )CO -return of blood to heart(R.atrium) via veins. CO = SV X HR Think simple! More in, More out _______ End-Diastolic Volume -blood left in the ventricles after diastole. EDV Designed by Pyeongsug Kim, ©2010

To increase venous return -Vasoconstriction caused by Symp. -Skeletal muscle pumps -Contraction of the diaphrgm during inhalation Venous pressure determines rate of blood return to the heart. Designed by Pyeongsug Kim, ©2010

Blood volume Protein concentration in blood plasma Oncotic pressure (colloid osmotic pressure) :Difference between osmotic pressures in and outside of capillaries. -High protein in the plasma -Low protein in the tissue. -Low protein in the plasma -High protein in the tissue. -Into the Blood(out of the tissue)-Into the tissue (out of the blood) Designed by Pyeongsug Kim, ©2010

What is edema and what causes?Edema -Excessive accumulation of tissue fluid -Normally filtration, osmotic reuptake, and lymphatic drainage maintain proper ECF levels. -High blood pressure or Venous obstruction -Increased tissue protein concentration -Decreased plasma protein concentration resulting from liver disease -Obstruction of lymphatic vessels -Leakage of plasma proteins into interstitial fluid -Myxedema (excess production of glycoproteins in extracellular matrix) from hypothyroidism Designed by Pyeongsug Kim, ©2010

-Hypothyroidism -Excess production of glycoproteins in extracellular matrix. Myxedema -Low protein in the plasma -High protein in the tissue. -Into the tissue (out of the blood) Designed by Pyeongsug Kim, ©2010

Blood volume Regulation Blood volume -By ___________ or _________ in kidney Reabsorption – Excretion - back to the blood exit via urine E: Glomerulus F: Nephron Blood volume regulated by two hormones. -ADH H 2 O reabsorption -Aldosterone Na+ & H 2 O reabsorption K+ excretion reabsorptionexcretion Designed by Pyeongsug Kim, ©2010

Regulation of plasma volume - ADH Plasma volume Plasma osmolity Osmotic pressure Detected by osmoreceptors in _____________ _____ is released Thirst ______ reabsorption Plasma volume Urine hypothalamus ADH H2OH2O Designed by Pyeongsug Kim, ©2010

Regulation of plasma volum Renin -secreted by the _____________ cells. -Converts Angiotensinogen to ____________ juxtaglomerular Angiotensin I Designed by Pyeongsug Kim, ©2010

Salt deficit, Low blood volume, or pressure ____________ is produced Aldosterone secretion Vasoconstriction Na+, H2O retention ↑Blood pressure, ↑ Blood volume Renin ACE *ACE: A ngiotensin- c onverting e nzyme angiotensin II Designed by Pyeongsug Kim, ©2010

-Secreted in posterior pituitary - ↑ Na+ & H 2 O reabsorption ↑ K+ excretion ADHAldosterone -When ↑Plasma osmolity Thirst! -When ↓Salt(Na+) ↓ Blood volume, ↓BP -Secreted in renal cortex -H 2 O reabsorption -↑ Blood volume ↓ Urine Flow -↑ Blood volume ↓ Na+ & H 2 O, ↑ K+ secretion ↓ Urine Flow * Vasoconstriction by___________ angiotensin II Designed by Pyeongsug Kim, ©2010

ANF(Atrial Natriuretic Factor) -produced in atria -response to high blood pressure Expanded blood volume  detected by stretch receptors in left atrium  release ANF -↑ -↑ water & salt excretion ↓ - ↓ aldosterone production - promotes ( vasodilation / vasoconstriction) Antagonistic effects of angiotensin II! Designed by Pyeongsug Kim, ©2010

Atrial Stretch Receptors -triggered by increased venous return -response to high blood pressure -act to reduce BP  by inhibiting ADH release  by promoting secretion of ANF ANF- atrial natriuretic factor - produced by atria - response to high blood pressure - reduces aldosterone  Increase water and salt excretion (↓ Na+ & H2O reabsorption)  Vasodilatation effect Designed by Pyeongsug Kim, ©2010

ANF (atrial natriuretic factor) High blood volume & pressure detected by stretch receptor in L.atrium ↑ ANF in atria ↓ ADH ↓aldosterone ↓ Na+, ↓ H 2 O, ↑ K+ reabsorption ↑Venous return ↑Urine, ↓Blood volume & pressure ↓H2O reabsorption Vasodilation Designed by Pyeongsug Kim, ©2010

Systemic circulations -The arteries supply blood to the organs in (parallel/series). : Arterial blood (does/does not) usually flow from one organ to another.  NOT “down stream” Changes in resistance within on organ directly affect blood flow in that organ ONLY. Designed by Pyeongsug Kim, ©2008 If “down stream” in blood supply -Vasoconstriction in a large organ  Blood flow through all organs might be reduced.

Vasodilatation  __ resistance to flow in the small arteries and arterioles.  __ Blood flow to organ. Blood flow ∆pressure resistance Resistance:______________________ Viscosity, thickness, length of vessel, smaller vessel Vaconstriction  __ resistance to flow in the small arteries and arterioles.  __ Blood flow to organ. Total peripheral resistance - The sum or all the vascular resistances within the systemic circulation Blood flow to Organ Designed by Pyeongsug Kim, ©2010

Powerful vasoconstrictor?(Vasopressin)_________ Extrinsic Regulation of Blood Flow -Regulated by _____ system and __________ system ANS Angiotensin II endocrine 1) ANS system Sympathetic __ cardiac output; __ peripheral resistance By alpha-adrenergic stimulation(NE) (vasoconstriction/vasodilation) in arterioles of skin (vasoconstriction/vasodilation) in arterioles of viscera(digestive tract, kidneys) By beta-adrenergic or cholinergic symp. fibers(ACh) (vasoconstriction/vasodilation) in arterioles of skeletal muscles Therefore, Blood flow: __ skin and viscera __ skeletal muscles Other vasopressin?(not significant in human)______ADH Designed by Pyeongsug Kim, ©2010

ANS system - Extrinsic Sympathetic 1) Sympathetic __ cardiac output __ peripheral resistance By alpha-adrenergic stimulation(NE) (vasoconstriction/vasodilation) - arterioles of skin - arterioles of viscera (digestive tract, kidneys) By beta-adrenergic or cholinergic symp. fibers(ACh) (vasoconstriction/vasodilation) - arterioles of skeletal muscles Therefore, Blood flow: __ skin and viscera __ skeletal muscles

ANS system - Extrinsic Parasymp. 2) Parasymp. Always cholinergic; Always (vasodilation/vasoconstriction) -Not found on many arterioles. Found on arterioles in salivary glands The effect is confined to _______________________. GI, genitalia, salivary glands Designed by Pyeongsug Kim, ©2008 Paracrine regulation of blood flow Paracrine regulation of blood flow  cell signaling During Inflammation -(vasodilation/vasoconstriction) by histamine, bradykinins...

Intrinsic regulation of blood flow Intrinsic regulation of blood flow( ___________) 1) Myogenic control -Organs try to maintain adequate blood flow.  by change the vascular smooth muscle to change in pressure -If ↓aterial pressure  ↓blood flow  (Vasodilation/vasoconstriction)  ↑blood flow -If ↑aterial pressure  ↑blood flow  (Vasodilation/vasoconstriction)  ↓blood flow 2) Metabolic control -Local vasodilation -In High metabolism(= Need for increased O 2 delivery)  Low O 2 or high CO 2 (= ↓pH), or release of adenosine or K+ from tissue  (vasodilation/ vasoconstriction) to ↑blood flow(more O 2 ) Autoregulation Designed by Pyeongsug Kim, ©2008 Cerebral blood flow -regulated primarily ( intrinsic / extrinsic )  Blood flow almost constant. low blood or O2 in brain  lose conscious ness

Blood flow in Brain Designed by Pyeongsug Kim, ©2008 Cerebral blood flowCerebral blood flow -regulated primarily ( intrinsic / extrinsic ) (myogenic and metabolic mechanisms.)  Blood flow almost constant. -Low blood or O2 in brain  lose consciousness -Less variation of blood flow Can least tolerate low rates of blood flow Stroke -an interruption of the blood supply to any part of the brain.

Cutaneous blood flowCutaneous blood flow -regulated primarily ( intrinsic / extrinsic ) -adjusted to maintain deep body temperature. -Vasoconstriction by sympathetic nerve. -Cold weather (or low body temp.) ↑ Sympathetic activity. low metabolic rate decrease  low blood flow (vasoconstriction)  Heat kept in the body not exercising -Warm weather (or high body temp. but not exercising) ↓ Sympathetic activity. increase blood flow (vasodilation), Perspiraition  to cool the body -During exercise increase blood flow(vasodilation) in both skin and skeletal muscle Blood flow in Skin Designed by Pyeongsug Kim, ©2008

At the beginning of exercise (Vasoconstriction/Vasodilation) in visceral  Less blood flow (Vasoconstriction/Vasodilation) in skeletal muscles  More blood flow As exercise continues -__ metabolism  ↓O2 and accumulation of CO2, K+, adenosin in the tissue.  Therefore, (Intrinsic/Extrinsic) regulation is major vasodilator. Designed by Pyeongsug Kim, ©2008 Blood flow during Exercise - Sympathetic activity Sympathetic nerve effects during exercise - SV and CO to increase vascular resistance - HR and ejection fraction increases vascular resistance Picture from

Designed by Pyeongsug Kim, ©2008 Coronary arterioles - (Symap./Parasymp.) activity Contain ______________ receptors. -NE causes (vasodilation/vasoconstriction) Epi. causes (vasodilation/vasoconstriction ) α & β adrenergic ____________________ -Abnormal deposition of lipids in the vessel wall -Coronary blood flow is reduced. -results in myocardial ischemia Atherosclerosis

Designed by Pyeongsug Kim, ©2008 Atherosclerosis

Sympathetic activation to the heart results in coronary vasodilation and increased coronary flow due to increased metabolic activity (increased heart rate, contractility) If parasympathetic activation of the heart results in a significant decrease in myocardial oxygen demand due to a reduction in heart rate, then intrinsic metabolic mechanisms will increase coronary vascular resistance by constricting the vessels. In the presence of coronary artery disease, coronary blood flow may be reduced. This will increase oxygen extraction from the coronary blood and decrease the venous oxygen content. This leads to tissue hypoxia and angina. Designed by Pyeongsug Kim, ©2008

What are variables that affect blood pressure? Designed by Pyeongsug Kim, ©2008 Blood pressure -Regulated by ______________________. *SV: stroke volume, HR: Heart rate TPR: total peripheral resistance HR, SV (blood volume), & TPR Total peripheral resistance -by vasodilation or vasoconstriction Symphathetic activity -__ HR and thus CO -__ systemic vascular resistance -Therefore, __BP Kidney -BP by regulating __________ and thus stroke volume. -by Hormones: _____ & __________ Blood volume ADHAldosterone

When ↑BP  the wall stretched.  __Frequency of APs transmitted to the _______________. Designed by Pyeongsug Kim, ©2008Baroreceptors -Stretch receptors -Loaced in arotic arch and carotid -Function for stable BP -activate by (increased/decreased) BP but, more sensitive to __BP & sudden changes in BP e.g ___________________ medulla oblongata In the medulla 1) Vasomotor control centers vasoconstriction or vasodilation 2) Cardiac center increase or decrease HR by symp. and parasymp. From lying down to standing

Baroreceptors When change position from lying down to standing -__ BP  ____________ is activated  APs to ______________  Inhibits (symp./parasymp.) and promotes (symp./parasymp.)  __ HR and (vasodilation/vasoconstriction)  Therefore, __ BP Baroreceptors medulla oblongata Designed by Pyeongsug Kim, ©2008

How is blood pressure measured? What is the significance of pulse pressure? Mean arterial pressure? Designed by Pyeongsug Kim, ©2008 When measure BP -Inflate above (systolic/diastolic) pressure, occluding artery. -Blood flows is only when (systolic/diastolic) pressure is above cuff pressure.  produce ______________. -Sounds are heard until cuff pressure equals (systolic/diastolic) pressure. Blood Pressure (BP) Korotkoff sounds Systolic P. -”Systole”: contraction of ventricle. Diastolic P. -”Diastolic”: resting phase of ventricle ___________________________ represents average arterial pressure during cardiac cycle. = _______________ +________________ Mean arterial pressure (MAP) diastolic pressure1/3 pulse pressure

How is blood pressure measured? What is the significance of pulse pressure? Mean arterial pressure? Designed by Pyeongsug Kim, ©2008 Dehydration or blood loss  (↑ / ↓)blood volume  (↑ / ↓)CO  (↑ / ↓) HR  increase in (systolic P./diastolic P.) Systolic P. –Diastolic P.  (↑ / ↓)Pulse P. ↑TPR and ↑HR increases the Diastolic P. more than Systolic P. *TPR: Total Peripheral Resistance Pulse pressure -reflects (CO/SV/HR).  can reflect CO since CO=SV X HR. = _______________ - ______________ systolic pressurediastolic pressure ↑CO increases the Systolic P. more than Diastolic P. *Both increase but Systolic P. more ↑CO (e.g. during exercise)  more increase in (systolic P./diastolic P.). Systolic P. – Diastolic P.  (↑ / ↓)Pulse P.

Designed by Pyeongsug Kim, ©2008 What compensations are performed by the body when blood pressure drops? When Blood pressure drops, 1) Baroreceptor reflex  inhibit (symp./parasymp.) promote (symp./parasymp.)  ____ and ______________  maintain an adequate BP. 2) Kidneys :↑Sympathoadrenal system  _____ by vasoconstriction of sterioles, ↑CO  ↑BP :↑Symp.  _____ by constriction of renal blood vessel, (↑/↓)urine output  ↑BP ↑COvasoconstriction Blood pressure – CO(HR, SV) X TPR(vasoconstriction) CO(HR, SV) X TPR(vasoconstriction) ↑TPR

Designed by Pyeongsug Kim, ©2010 Congestive Heart Failure -Occurs when cardiac output is insufficient to maintain blood flow for body.; Impaired pumping capability  can't pump enough blood to the body's other organs. -Compensatory response ~ due to low CO. increase heart rate ~ CO = SV X HR. increase renin (Na+, H2O retention)  blood volume increase  EDV increase  enlarged ventricles!!  compensatory makes worse!!!! -Causes Coronary artery disease, heart disease, hypertension, electrolyte imbalance -Treated with digitalis, vasodilators, and diuretics Digitalis increases contractility of heart muscle. Diuretics lower blood volume. Nitroglycerin is a vasodilator.

Cardiomegaly Cardiomegaly (or Cadiomyopathy) -Heart is enlarged -Due to ventricular hypertrophy Designed by Pyeongsug Kim, ©2010