CARDIAC OUTPUT
How many liters of blood does a person have at rest?
5.25 liters FOR EXAMPLE: HR x SV =CO 5beats/min x 70ml/beat = 5.25L/min 75 beats per minute x 70 mls (on average SV people at rest - every time heart contracts the ventricle ejects 70 mls of blood)
What is a cardiac cycle?
A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles
How do Chronotropic Agents affect cardiac output?
An AGENT could be a drug or a hormone that can increase or decrease Heart Rate Ex: Dopamine Epinephrine Acetylcholine Beta Blockers These hormones and drugs affect the sympathetic and parasympathetic nervous system
What do Ionotropic agents do?
An agent could be a drug or a hormone that INCREASE OR DECREASE STROKE VOLUME -it alters the force of a contraction EX: milrinone, digoxin, dopamine, and dobutamine are used to increase the force of cardiac contractions.
What is the term for the amount of blood pumped by a single ventricle in one minute?
CARDIAC OUTPUT
What are two external factors that affect Cardiac Output?
Chronotropic and Ionotropic Agents
WHAT DO NEGATIVE AMOUTS OF CHRONOTROPIC AGENTS DO?
DECREASE HEART RATE EX: ACETYLCHOLINE or BETA BLOCKERS (Impact the Para-sympatheic Nervous system) Anything that causes a para-sympathetic activity or a DECREASE in Heart Rate is a negative Chronotropic Agent.
What is AFTER LOAD?
Due to the amount of pressure holding the aortic valve shut the ventricle resists ejecting blood into circulation The pressure in the ventricle has to become greater than the pressure in the arteries. We need to overcome the afterload to eject blood into circulation.
The number of heart beats per minute (or the number of cardiac cycles) per minute is?
HEART RATE
How do you find the level of Cardiac Output? (MATH EQUATION)
Heart Rate x Stroke Volume = Cardio Output HR x SV= CO
What does cardio output tell a lot about?
How well the heart is functioning. (Cardiac Function)
WHAT DO POSITIVE AMOUTS OF CHRONOTROPIC AGENTS DO?
INCREASED HEART RATE EX: DOPAMINE and EPINEPHRINE (Impact the sympathetic Nervous system) Anything that causes a sympathetic nervous system activity INCREASES Heart Rate is a positive Chronotropic Agent
What is the Frank Sterling Law of the heart
It's the idea that. . . the more the ventricular muscle cells are stretched, the more blood the ventricle can hold and the more forcefully it will contract. THIS LEADS TO INCREASE IN STROKE VOLUME INCREASE IN CARDIO OUTPUT
What is Cardiac Output measured in?
LITERS per minute
negative ionotropic agents
Negatively inotropic agents weaken the force of muscular contractions. DECREASES STROKE VOLUME Decrease of calcium Decrease of contraction Decrease in stroke volume.
positive ionotropic agents
Positively inotropic agents increase the strength of muscular contraction. INCREASES STROKE VOLUME increase of calcium increase of contraction increase in stroke volume.
What is the amount of blood ejected per beat?
STROKE VOLUME
TRUE OR FALSE Anything that impacts on Heart Rate and Stroke Volume also impact volume of blood pumped per minute or Cardiac Output
TRUE
TRUE OR FALSE Anywhere between 5-6 LITERS is the average cardiac output for a person at rest.
TRUE
TRUE OR FALSE As contractions increase volume of electable blood increase.
TRUE
TRUE OR FALSE Cardiac Output is the way to measure the effectiveness of the cardiovascular system.
TRUE
TRUE OR FALSE The cardiovascular system is a closed system and the blood flows in one direction.
TRUE
TRUE OR FALSE VENOUS RETURN & AFTER LOAD are two other variables that impact cardiac output?
TRUE
TRUE OR FALSE Calcium concentration impacts the strength of heart contraction?
TRUE
What is volume of blood returning to heart called?
VENOUS RETURN
Does the efficiency of the the veins at bring blood back to the heart will impact on Stroke Volume?
YES
