Cardiac Output and Regulation

Terminology

100

The value known as beats per minute

heart rate

200

The amount of blood pumped into the pulmonary and systemic circuits in 1 minute - from the ventricles

cardiac output

300

The amount of blood pumped into one heartbeat

stroke volume

400

The amount of blood in the ventricle at the end of a contraction

end-systolic volume (ESV)

500

The amount of blood in the ventricle after it has filled during diastole

end-diastolic volume (EDV)

Cardiac Output

100

EDV - ESV = ?

120ml - 50ml = ?

stroke volume

200

HR x SV = ?

70 beats/min x 70ml/beat = ?

cardiac output

300

Cardiac output is affected by what factors?

age/body size/gender and oxygen demand 

400

Can heart disease reduce CO?

True

500

Normal range for CO

5000mL or 5L 

Influences on SV

100

The degree to which the sarcomeres in the ventricular cells are stretched before they contract

preload

200

The pumping ability, or the ability to generate tension

contractility 

300

The force that the right and left ventricles must overcome in order to eject blood into their respective arteries 

afterload

400

Name some negative influences on SV

high blood pressure, sudden drop in blood pressure, sudden drop in blood volume, extremely fast HR 

500

Name some positive influences on SV

increased sympathetic stimulation, increased venous return, slower HR, exercise, increased Ca++

Influences on HR

100

Rate of this firing determines HR

SA node depolarizing

200

Factors that determine the rate at which the SA node generates action potentials

chronotropic agents 

positive chronotropic agents: anything that increases firing of SA node

negative chronotropic agents: opposite is true

300

Example of a positive chronotropic agent

sympatehtic nervous system, certain hormones, and elevated body temeprature

400

Example of a negative chronotropic hormone

parasympathetic nervous system and decreased body temperature

500

Difference between agaonistic versus antagonistic 

agonist: a drug that binds the receptor and mimic the effects of NE

anagonists: a drug that blocks the receptor and prevent the binding of NE to it

Regulating CO

100

Innervation of a system with nerves that release NE to increase HR is dependent upon the body's needs

sympathetic nervous system

200

The ions in which the sympathetic nervous system releases in order to increase HR

calcium ions

300

The sympathetic nervous system influences which node to fire faster to increase HR?

SA node

400

By increasing calcium ion concentration in cardiac cells and firing SA node faster, we can increase what?

contractility --> SV

500

Hormones that are released into the blood by the endocrine system to influence cardiac output

Epi, NE, thyroid hormone, glucagon

by controlling water balance: aldosterone, ADH