Chapter 13: Cardiovascular System
blood pressure is the force of blood against the inner walls of blood vessels anywhere in the cardiovascular system, although the term "blood pressure" usually refers to what?
arterial pressure
what are strong, elastic vessels adapted for carrying high-pressure blood away from the heart?
arteries
arteries become smaller as they divide and become ______________
arterioles
where are the semilunar valves found?
at the exits from the ventricles
upper chambers, __________ , receive blood returning to the heart, and have thin walls and ear-like auricles projecting from their exterior
atria
what is it called while the atria relax?
atrial diastole
the cardiac cycle consists of the atria beating in unison, called what?while the ventricles rest, called ____________________
atrial systole, ventricular diastole
The heart lies _____________ to the sternum; its apex extends to the ___________ intercostal space.
posterior, fifth
what can regulate the amount of blood entering a capillary bed, and what are they controlled by?
precapillary sphincters, the oxygen concentration in the area
path of blood through the heart→ Superior and inferior vena cava, _________________, _______________ valve, _____________________, ___________________ valve, _____________________, pulmonary arteries, _______________________ of lungs, ________________________, _____________, __________________ valve, __________________, ___________ valve, and through the arteries to provide blood to the body cells.
right atrium, tricuspid, right ventricle, pulmonary, pulmonary trunk, pulmonary capillaries, pulmonary veins, left atrium, bicuspid / mitral, left ventricle, aortic
if blood is needed elsewhere in the body, what do the capillary beds in less important areas do?
shut down
specialized cardiac muscle tissue conducts impulses throughout the myocardium and comprises the cardiac conduction system. A self-exciting mass of specialized cardiac muscle called the _________________ __________, located in the posterior right atrium, generates the impulses for heartbeats. Therefore, it is also called the ____________________ of the heart.
sinoatrial node, pacemaker
contractions of what muscles squeeze blood back up veins one valve at a time?
skeletal
what also influences heart rate?
body temperature and the concentrations of certain ions
blood pressure is partially determined by what?
cardiac output and peripheral resistance
what are the four factors that affect blood pressure?
cardiac output, blood volume, peripheral resistance to blood flow, and viscosity of the blood
the _____________ control center of the _____________ _____________ maintains a balance between the two autonomic divisions of the nervous system in response to messages from ______________________, which detect changes in what?
cardiac, medulla oblongata, baroreceptors, blood pressure
what veins drain blood from the heart muscle, and carry it to the coronary __________, which drains into the right atrium?
cardiac, sinus
(ECG) in each case, what leads to contraction of the chamber, and what leads to relaxation?
depolarization, repolarization
what are the factors that can affect these variables or cardiac output?
emotions, exercise, body temperature, the volume of blood entering the heart chambers and the size of the heart
what is the inner layer called and what is it made up of?
endocardium; its smooth and is made up of connective tissue and epithelium, and is continuous with the endothelium of major vessels joining the heart
capillaries are the smallest vessels, consisting only of a layer of what? through which substances are exchanged with tissue cells
endothelium
the outermost layer, the ________________, is made up of connective tissue and epithelium, and contains ___________ and _______________________ along with _________________ arteries that provide blood to the heart
epicardium, blood, lymph capillaries, coronary
veins have the same three layers as arteries, and have what inside to prevent backflow of blood?
flap-like valves
impulses from the ____________ speed up and impulses from the ___________ slow down heart rate
former, latter
which part of the pathway is systemic?
from the left ventricle, to the body cells through the aorta, systemic arteries, capillaries and veins, and returning to the right atrium through the superior and inferior vena cava
which part of the blood pathway is pulmonary?
from the right ventricle, through the pulmonary trunk, arteries, capillaries, and veins, and returning to the left atrium
what is a mass of merging fibers that act as a unit called?
functional syncytium; one exists in the atria and one in the ventricles
areas with a great deal of metabolic activity (leg muscles, for example) have ________________ densities of __________________
higher, capillaries
when the atria fill, pressure in the atria is __________ than that of the ventricles, which forces which valves to open?
higher, tricuspid and mitral
what drives the passage of fluids and small molecules out of the capillary?
hydrostatic pressure
when the ventricles contract, pressure inside them _______________ sharply, causing what?
increases, causes the tricuspid and mitral valves to close, and the pulmonary and aortic valves to open.
what shape is the heart and where is it located?
is a hollow, cone-shaped, muscular pump within the mediastinum and rests on the diaphragm
heart sounds can be described as what sound?
"lubb-dupp"
what wave ends the ECG pattern and corresponds to ventricular repolarization?
T wave
cardiac output is the product of ___________ volume and heart rate, and a number of factors can affect these variables
stroke
blood pressure at the venular end of a capillary is almost what? so other factors help return the blood to the heart.
0
what is the size of the average adult heart?
14 cm long and 9 cm wide
how many layers does the pericardium consist of?
2
the wall of the heart is composed of how many distinct layers?
3
the heart has how many internal chambers?
4; two upper chambers and two lower chambers
what capillaries collect excess tissue fluid and return it to the circulation?
lymphatic
the impulse proceeds to the next conduction structure, the _____ bundle , which splits into the left and right ________________________. These branches give rise to ___________________ fibers, which lead into the ventricular myocardium and the papillary muscles.
AV, bundle branches, purkinje
what is the middle layer called and what does it consist of?
myocardium; it consists of cardiac muscle and is the thickest layer of the heart wall
(ECG) what is the first wave and what does it correspond to?
P wave; corresponds to the depolarization of the atria
what complex corresponds to the depolarization of the ventricles and hides the repolarization of the atria?
QRS
at the venular end of the capillary, what (due to the proteins in the blood) causes much of the tissue fluid to return to the bloodstream?
osmotic pressure
blood entering capillaries contains high concentrations of what? that diffuse out of _________________ and into the __________________
oxygen and nutrients, the capillary wall, tissue fluids
as the ventricles contract, _____________ muscles contract, pulling on ____________________________ and preventing the backflow of blood through the tricuspid and mitral valves
papillary, chordae tendineae
the chordae tendineae, in turn, attach to ________________ muscles in the inner heart wall, which contract during ventricular contraction to prevent what?
papillary, the backflow of blood through the AV valves
the surge of blood that occurs with ventricular contraction can be felt at certain points in the body as what?
a pulse
what divides the chambers on the left side from those on the right?
a septum
the heart muscle requires a continuous supply of oxygen-rich blood, so smaller branches of arteries often have __________________ as alternate pathways for blood, in case what happens?
anastomoses, in case one pathway became blocked
what are the functions of the CV system?
supplies oxygen and nutrients to tissues and removes wastes from them
the SA node is innervated by branches of what divisions of the nervous system, so the CNS helps to control heart rate?
sympathetic and parasympathetic
impulses spread next to the atrial _________________; it contracts, and impulses travel to the junctional fibers leading to what node located in the septum?
syncytium, atrioventricular
junctional fibers are small, which allow what?
the atria to contract before the impulse spreads rapidly over the ventricles
what form a closed tubular system that carries blood away from the heart, to the cells, and back again?
the blood vessels (arteries, arterioles, capillaries, venules, and veins)
arterial blood pressure rises and falls, following a pattern established by what? during ventricular contraction, arterial pressure is at its _______________ or _____________ pressure. when the ventricles are relaxing, arterial pressure is at its ____________ or ______________ pressure.
the cardiac cycle, maximum, systolic, minimum, diastolic
impulses from where may also influence the cardiac control center?
the cerebrum or hypothalamus
the amount of blood pumped at any time must adjust to what?
the current needs of the body (more is needed during strenuous exercise)
what does the cardiovascular system consist of?
the heart and blood vessels (arteries, capillaries and veins)
rings of dense connective tissue surround the pulmonary trunk and aorta to provide attachments for what? These tough rings prevent dilating of tissue in this area.
the heart valves and muscle fibers
what are the 2 layers of the pericardium?
the outer, tough connective tissue, fibrous pericardium, surrounds a more delicate double-layered sac that surrounds the heart the inner layer directly covers the heart and is called the visceral pericardium, or epicardium
at the base of the heart, what does the inner layer fold back to become?
the parietal pericardium
between the visceral and parietal layers of the pericardium is a potential space called what? and what is it filled with?
the pericardial cavity and is filled with serous fluid, which reduces friction
blood vessels can be divided into what 2 major pathways?
the pulmonary circuit, which goes from the heart to the lungs and back the systemic circuit, which goes from the heart to the body cells and back
what are the first branches off of the aorta, which carry oxygen-rich blood, that feed the heart muscle itself? Branches of these arteries feed many capillaries of the myocardium
the right and left coronary arteries
the wall of an artery consists of an inner endothelial layer, called what?
the tunica interna
the first sound (lubb) occurs as what happens?
the ventricles contract and the tricuspid and mitral valves are closing
how do veins differ from arteries?
they are thinner, less muscular, and the blood is at much lower pressure in the veins
why do plasma proteins remain in the blood?
they are too large to get through the capillary walls
differences in _______________ and ________________ pressures, derived from the breathing process, draw blood back up the veins
thoracic, abdominal
what is the function of systemic circulation?
to distribute oxygen and nutrients to tissues throughout the body
what is the function of pulmonary circulation?
to oxygenate the blood and remove carbon dioxide
what is the function of the semilunar valves?
to prevent backflow of blood into ventricles as the ventricles relax
the right atrioventricular (AV) valve, called ____________ valve, and left AV valve, called either _______________ or the ____________ valve, have cusps to which strings called __________________ attach
tricuspid, bicuspid, mitral, chordae tendineae
what is the outermost layer of connective tissue?
tunica externa
what is the middle layer of an artery wall, called and what is it made up of?
tunica media; made up of smooth muscle and elastic connective tissue
during the cardiac cycle, pressure within the heart chambers rises and falls. These pressure changes open and close what?
valves
arteries are capable of ______________________ as directed by sympathetic impulses; when impulses are inhibited, the diameter of the vessel increases, which is called _________________
vasoconstriction, vasodilation
the ______________ center of the ____________________ in the brain stem can adjust sympathetic impulses to __________________ in arteriole walls, adjusting blood pressure
vasomotor, medulla oblongata, smooth muscle
the second sound (dupp) occurs as what happens?
ventricles relax and aortic and pulmonary valves are closing
below the atria, the thick-muscled ________________ pump blood to the ________ and __________
ventricles, body and lungs
what is the contraction of both ventricles called?
ventricular systole
small vessels called ______________ lead from capillaries, and merge to form larger ____________ that return blood to the heart
venules, veins
what is the epicardium the same as?
visceral pericardium
