NU 578 Exam 3 Study guide
CHAPTER 36: HEMODYNAMICS P. 281
• Circulatory System
o delivers oxygen, nutrients, hormones, electrolytes, and other essentials to cells; removes
carbon dioxide and metabolic wastes from cells.
o helps fight infection
o divided into pulmonary and systems circulations.
o Components 251
▪ Arteries: transport blood under high pressure to tissues. very muscular, do not
stretch well. increased pressure only slightly increases diameter.
▪ Arterioles: control vessels that regulate local blood flow
▪ Capillaries: sites for exchange of fluid, oxygen, carbon dioxide, nutrients,
hormones, and wastes
▪ Venules: collect blood from capillaries
▪ Veins: transport blood TO THE HEART. they are a major reservoir for blood.
Less muscular. more distensible. small increase in pressure largely increases
diameter -> large increase in volume
o Blood distribution
▪ 5L total in circulation
▪ 9% in pulmonic circulation
▪ 7% in heart
▪ 84% in systemic circulation
▪ 64% in venules, veins, sinuses.
▪ 13% in arteries
▪ 7% in arterioles or capillaries
o Starling Law P. 283
▪ "the force of ventricular contraction is proportional to muscle fiber length (up
to a point). As fiber length (ventricular diameter) increases, there is
corresponding increase in contractile force. "
▪ when venous return increases, CO increases. When venous return decreases,
CO decreases. SV affected by venous return.
▪ actin and myosin align better with increased ventricular filling.
▪ In the failing heart, the Starling law breaks down. O
• That is, the force of contraction no longer increases in proportion to
increased ventricular filling.
• As a result, blood backs up behind the failing ventricle.
• In this example, output of the left ventricle is 1% less than the output
of the right ventricle, which causes blood to back up in the pulmonary
circulation.
Downloaded by harun mburu ()
, • In only 20 mins, this small imbalance between left & right ventricular
output shifts a liter of blood from the systemic circulation to the
pulmonary circulation.
• In less than 40 mins, death from pulmonary congestion would ensue.
• This example underscores the importance of systemic-pulmonary
balance & the critical role of the Starling mechanism in maintaining it
o Factors affecting venous return
▪ systemic filling pressure, the auxiliary muscle pumps, resistance to flow bt
peripheral vessels and the right atrium, and right atrial pressure (elevation
impedes venous return) have what affect circulation?
▪ Note: only the first one can be manipulated by drugs
• RAAS System P. 284
o supports AP by causing constriction of arterioles and veins, retention of water by
kidneys.
o angiotensin II -> vasoconstriction
o aldosterone -> sodium and water retention
o vasoconstriction takes hours, water retention takes days
• Kidney water retention
o this may occur if AP remains low for a long time.
o pressure rises because fluid builds up in blood volume -> increased venous pressure ->
increased CO -> increased AP.
o works over weeks, months, to years
• ADD MORE?
CHAPTER 37: DIURETICS P. 286
• Diuretics increase urine output!
• Two major applications: treat
HTN, mobilize edematous fluid
from HF, prevent renal failure
(maintain urine flow)
• Overview of Kidney Function:
cleanses ECF and maintains ECF
volume/composition (affected
MOST by diuretics); maintain acid-
base balance; excretes metabolic
wastes/foreign substances (drugs,
toxins)
Downloaded by harun mburu ()
CHAPTER 36: HEMODYNAMICS P. 281
• Circulatory System
o delivers oxygen, nutrients, hormones, electrolytes, and other essentials to cells; removes
carbon dioxide and metabolic wastes from cells.
o helps fight infection
o divided into pulmonary and systems circulations.
o Components 251
▪ Arteries: transport blood under high pressure to tissues. very muscular, do not
stretch well. increased pressure only slightly increases diameter.
▪ Arterioles: control vessels that regulate local blood flow
▪ Capillaries: sites for exchange of fluid, oxygen, carbon dioxide, nutrients,
hormones, and wastes
▪ Venules: collect blood from capillaries
▪ Veins: transport blood TO THE HEART. they are a major reservoir for blood.
Less muscular. more distensible. small increase in pressure largely increases
diameter -> large increase in volume
o Blood distribution
▪ 5L total in circulation
▪ 9% in pulmonic circulation
▪ 7% in heart
▪ 84% in systemic circulation
▪ 64% in venules, veins, sinuses.
▪ 13% in arteries
▪ 7% in arterioles or capillaries
o Starling Law P. 283
▪ "the force of ventricular contraction is proportional to muscle fiber length (up
to a point). As fiber length (ventricular diameter) increases, there is
corresponding increase in contractile force. "
▪ when venous return increases, CO increases. When venous return decreases,
CO decreases. SV affected by venous return.
▪ actin and myosin align better with increased ventricular filling.
▪ In the failing heart, the Starling law breaks down. O
• That is, the force of contraction no longer increases in proportion to
increased ventricular filling.
• As a result, blood backs up behind the failing ventricle.
• In this example, output of the left ventricle is 1% less than the output
of the right ventricle, which causes blood to back up in the pulmonary
circulation.
Downloaded by harun mburu ()
, • In only 20 mins, this small imbalance between left & right ventricular
output shifts a liter of blood from the systemic circulation to the
pulmonary circulation.
• In less than 40 mins, death from pulmonary congestion would ensue.
• This example underscores the importance of systemic-pulmonary
balance & the critical role of the Starling mechanism in maintaining it
o Factors affecting venous return
▪ systemic filling pressure, the auxiliary muscle pumps, resistance to flow bt
peripheral vessels and the right atrium, and right atrial pressure (elevation
impedes venous return) have what affect circulation?
▪ Note: only the first one can be manipulated by drugs
• RAAS System P. 284
o supports AP by causing constriction of arterioles and veins, retention of water by
kidneys.
o angiotensin II -> vasoconstriction
o aldosterone -> sodium and water retention
o vasoconstriction takes hours, water retention takes days
• Kidney water retention
o this may occur if AP remains low for a long time.
o pressure rises because fluid builds up in blood volume -> increased venous pressure ->
increased CO -> increased AP.
o works over weeks, months, to years
• ADD MORE?
CHAPTER 37: DIURETICS P. 286
• Diuretics increase urine output!
• Two major applications: treat
HTN, mobilize edematous fluid
from HF, prevent renal failure
(maintain urine flow)
• Overview of Kidney Function:
cleanses ECF and maintains ECF
volume/composition (affected
MOST by diuretics); maintain acid-
base balance; excretes metabolic
wastes/foreign substances (drugs,
toxins)
Downloaded by harun mburu ()
