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Chapter 17 - Exam 2
Terms in this set (102)
What is the primary function of the heart?
to pump blood through the pulmonary and systemic circulatory systems
what does the heart provide homeostasis for?
What are the two circuits of the cardiovascular system?
pulmonary and systemic circuits
the heart ensures one-way blood flow by using ______?
what hormone is produced by the heart?
what does ANP do?
lowers blood pressure
How does ANP lower blood pressure?
increases Na+ and water excretion
What is the pericardium?
double layered membrane or sac that covers the outside of the heart
the pericardium has two structures called the _________ pericardium (superficial) and ________ pericardium (deep)
What is the fibrous pericardium composed of?
what is the function of the fibrous pericardium?
anchors the heart to surrounding structures
the serous pericardium is composed of the ___________ pericardium (superficial) and _____________ pericardium (deep).
another name for visceral pericardium is ____________?
what is the space between the parietal and visceral pericardia called?
what is the function of the pericardial cavity?
decreases friction and prevents rubbing on the sternum
what liquid fills the pericardial cavity?
the visceral pericardium is considered the most _________________ (superficial or deep) layer of the heart wall.
? what are the three layers of heart wall? list superficial too deep.
epicardium, myocardium, endocardium
the myocardium is composed of
cardiacs muscle tissue and a fibrous skeleton
what type of cells make up cardiac muscle tissue?
what type of tissue makes up fibrous skeleton?
dense irregular connective tissue
what part of the heart provides electrical insulation?
what type of tissues is the endocardium (deepest layer of the heart) composed of?
simple squamous epithelium and several layers of CT with elastic and collagen fibers
What is cardiac tamponade?
pericardial cavity becomes filled with excess fluid
where does the superior vena cava drains deoxygenated blood from?
superior to the diaphragm (head, neck, thorax, and upper limbs)
where does the inferior vena cava drain deoxygenated blood from?
inferior to the diaphragm (abdominopelvic cavity and lower limbs)
where does the superior/inferior vena cava send blood to?
the pulmonary trunk receives blood from the?
where do the pulmonary veins send blood?
Name two circuits the aorta sends blood to?
systemic and coronary circuits
blood drains into the right atrium from the ________________, ________________, and the ________________.
superior vena cava; inferior vena cava; coronary sinus
where does blood in the right ventricle flow to next?
where does blood in the left ventricle flow to next?
what is the coronary sulcus?
groove between atria and ventricles
what is the interatrial septum?
separates right and left atria
What is the interventricular septum?
separates the right and left ventricles
what do the atrioventricular valves separate?
atria from ventricles
what structure anchors atrioventricular vales to the heart wall?
what is the function of chordae tendinae?
prevent blood from flowing back into the atria
what side of the heart is the tricuspid valve located?
what side of the heart is the mitral bicuspid valve located?
what part of the heart is the pulmonary semilunar valve?
what part of the heart is the aortic semilunar valve?
what type of cells are striated, short and thick, uninucleate, and contain desosmones and gap junctions?
cardiac muscle cells
what type of cells are long, thin, striated, arranged parallel to another, and are multinucleate?
skeletal muscle cells
Name one type of nonselective cation channel.
Pacemaker cell channel
what is the depolarization rate of the Sinoatrial Node (SA node)?
where is the SA node located?
what is the function of the SA node?
generate action potentials
What is the depolarization rate of the Atrioventricular node (AV node)?
where is the AV node located?
junction of atria and ventricles
What is the AV node?
cluster of pacemaker cells
what is the depolarization rate of the Purkinje Fibers System?
Purkinje fibers function?
fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract
contractile cells make up _____% of cardiac muscle cells
Pacemaker Action Potential Pathway:
SA node generates action potential → AV node → AV bundle → right and left bundle branches → Purkinje fibers → contractile cells of the ventricles
Phases of a Contractile Cell AP
1. Rapid Depolarization Phase; 2. Initial Depolarization phase; 3. Plateau Phase; 4. Depolarization phase
Rapid Depolarization Phase (contractile cell AP graph)
VG-Na+ channels open, NA+ enters cell rapidly; -85mV → +20 mV
Initial Depolarization Phase (contractile cell AP graph)
Na+ channels inactive; Some K+ channels open; K+ leaks out of cell; Causes a small initial repolarization
Plateau Phase (contractile cell AP graph)
Slows down HR; provides time for heart to fill with blood
Increases strength of contraction
Lengthens the refractory period
Ca2+ channels open; Ca2+ enters cell
K+ exits cell
Repolarization Phase (contractile cell AP graph)
Na+ and Ca2+ channels close;
K+ continues to exit;
Ions involved in dep./rep./plateau phases?
Na+, K+, Ca2+
What is the refractory period?
a period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation. they cannot contract again during this time.
what phase does the refractory period occur?
depolarization of the atria
depolarization of ventricles; simultaneously depolarizes atria
depolarization of ventricles
the cardiac cycle moves blood from high-to-low/low-to-high concentration?
what is the average blood pressure?
the top number in BP is called
the bottom number in BP is called
Contracting of the heart
Relaxation of the heart
What the steps of Cardiac Cycle
1. Ventricular Filling; 2. Period of Isometric Contraction; 3. Period of Ejection; 4. Period of Isovolumetric Relaxation
What happens during "Ventricular Filling"?
Ventricles fill with blood → diastole
Atrioventricular valves are open allowed blood to flow into
Atrial systole (contraction) occurs to push remaining blood into ventricles
Semilunar valves are closed
What happens during "Period of Isovolumetric Contraction"
Ventricular systole (contract) begins
AV and semilunar valves are both closed because there is not enough pressure to open semilunar valves
Atrial diastole (relaxation) begins
What happens during "Period of Ejection"?
Ventricular systole (contraction) continues
AV valves still closed
Atrial diastole continues
Pressure opens SL valves and blood → pulmonary artery/aorta
What happens during "Period of Isovolumetric Relaxation"?
Ventricular diastole begins
AV valves are still closed
Atrial diastole continues
SL valves close
how much pressure you need in the ventricle to EJECT blood into their respective arteries
MAP = CO x PR
what does MAP mean?
mean arteries pressure = average BP in aorta
MAP = CO x PR
What does CO mean?
amount of blood pumped by her per minute
MAP = CO x PR
what does PR mean?
peripheral resistance = total resistance against which blood must be pumped
CO = SV x HR
what does SV mean?
volume of blood pumped per ventricle per contraction
what is the average SV?
CO = SV x HR
What does HR mean?
what is the average heart rate?
SV x HR = CO
70mL/beat x 72beats/min = 5040mL/min ~ 5L/min
how much the sarcomeres in ventricular walls are stretched before they contract; determined by how much blood has drained into ventricles by the end of filling phase
What are the factors that influence SV?
preload; contractility; after load
Refers to the force that the right and left ventricles must overcome in order to eject blood into their respect arteries
what is the relationship between Afterload and Stroke Volume?
↓ Stroke Volume
What is the relationship between Stretch, Force of Contraction, and Stroke Volume?
↑ stretch ↑ force of contraction ↑ stroke volume
What is Starling's law of the heart?
The further the cardiac cells are stretched by incoming blood, the greater the strength of the contraction
how does the sympathetic nervous system affect cardiac output?
Sympathetic nerves INCREASE the rate of force of contraction
What is the relationship between Norepinephrine and cardiac output?
Increases cardiac output; increases HR
norepinephrine and epinephrine are secreted from which gland?
what is the relationship between Acetycholine and cardiac output?
decreases cardiac output; decreases HR
which nervous system is Acetylcholine a part of?
parasympathetic nervous system
What number is the Vagus Nerve?
CN X (10)
What is the relationship between the CN X and cardiac output?
decrease cardiac output, decrease HR
Which hormone/s INCREASE blood volume, preload, and cardiac output?
ADH & Aldosterone.
Which hormone/s DECREASE blood volume, preload, and cardiac output?
Recommended textbook explanations
Introduction to Anatomy and Physiology
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Essentials of Human Anatomy and Physiology
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Human Physiology: From Cells to Systems
Hole's Essentials of Human Anatomy and Physiology
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