Chapter 12: The Heart Flashcards
What is the approximate weight of the heart
less than one pound
where is the heart located
the mediastinum
What are the membranous layers of the heart
The outer fibrous pericardium (pericardial sac), parietal pericardium, visceral pericardium (epipericardium), pericardial cavity
What are the layers of the heart wall
epicardium, myocardium, endocardium
what makes the lub sound
closing of the av valves
what makes the dub sound
closing of semilunar valves
what is the pulmonary circuit
superior and inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary trunk, lungs
What is the systemic circuit
lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta, body tissues
what is the coronary circuit
lungs, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta, heart tissue, coronary sinus, cardiac veins
define atherosclerotic plaque
fatty deposits in the lining of coronary arteries
define angina pectoris
chest pain from exertion that subsides when the activity is stopped
define myocardial infarction (MI)
when there is a 100% blockage in a coronary artery
define angioplasty
procedure using a catheter with a small balloon that is inflated at sites of atherosclerosis to widen the lumen
define coronary bypass
procedure where a vessel is grafted onto the heart to go around a partially blocked region
what ions prolong the peak of the action potential in cardiac muscle
calcium ions
what does a myogram do
measures the tension produced by muscle
what is the conduction system in order
sinoatrial node, atrioventricular node, atrioventricular bundle, R+L bundle, purkinje fiber
what does the p wave represent on an ECG
atrial depolarization
what is the QRS complex representing
ventricular depolarization
what does the t wave represent
ventricular repolarization
define arrhythmia
any abnormality in the electrical activity of the heart; many types; can be detected with electrocardiograms
define tachycardia
heart rate greater than 100 bpm
define bradycardia
heart rate less than 60 bpm
define fibrillation
out of phase electrical activity, heart is useless as a pump
What are the steps in the cardiac cycle
- Heart in diastole - av valves open and ventricles fill
- Atrial systole
- Begin ventricular systole - av valves close
- Mid to late Ventricular systole - ventricular psi is greater than artery psi
- Being ventricular diastole - ventricular psi less than psi in artery; semilunar valves close
How do you determine Cardiac Output
multiple bpm by the rest of the stroke volume
what is cardiac output
volume of blood pumped by the heart in one minute
what is stroke volume
volume of blood pumped per ventricle in one beat
what is EDV (preload)
volume of blood in the ventricle at the end of diastole
What is ESV
volume of blood in the ventricle at the end of systole
what is preload
degree to which ventricles are stretched at EDV
what is afterload
pressure against which the ventricles must pump
stretching of the atria stimulates this reflex
atrial/ bainbridge reflex
when there is a ______ in venous, there is a ________ in heart rate and force of contraction
increase; increase
in venous return and filling time tachycardia has a ______ in filling time
decrease
in venous return and filling time in bradycardia has a ______ in filling time
increase
stretching the ventricles stimulates this reflex
starlings law of the heart (more in=more out)
The Cardioregulatory Center is in which part of the brain
medulla oblongata
The parasympathetic NS is associated with which nerves
vagus nerves
The sympathetic NS is associated with which nerves
cardiac nerves
What is the neurotransmitter in the parasympathetic NS
acetylcholine
what is the role of acetylcholine in the parasympathetic NS
decrease the Heart Rate and Stroke Volume
what is the neurotransmitter in the sympathetic NS
norepinephrine
what is the role of norepinephrine in the sympathetic NS
increase Heart Rate and Stroke Volume
What does the suprarenal (adrenal) medulla secrete
epinephrine and norepinephrine
What is the baroreceptor reflexes
response to increased BP
when CO is increased, BP is ______
increased
when CO is decreased, BP is ________
decreased
What is the Baroreceptor Reflex stimulus
increased BP
what are the Baroreceptor Reflex receptors
baroreceptors pertaining to the carotid sinus and aortic arch
what are the Baroreceptor Reflex sensory nerves
the glossopharyngeal and the vagus nerve
what are the Baroreceptor Reflex effectors
cardioregulatory center of medulla oblongata (PNS, SNS)
what are the Baroreceptor Reflex response
decreased blood pressure
What is the role of the Renin-Angiotensin-Aldosterone Mechanism
Regulates blood volume + BP
What is renin?
an enzyme produced by kidneys
what does renin do?
convert angiotensinogen into angiotensin 1
What is aldosterone
a hormone produced by the adrenal cortex
what does aldosterone do?
Targets kidneys to reabsorb Na+ and secrete K+
What is ADH
a hormone produced by the hypothalamus, and stored in the posterior pituitary
What does ADH do
targets the kidneys to reabsorb H2O and increase blood volume + blood pressure
