17.5: Internal Structures of the Heart
- Page ID
- 53779
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)
( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\id}{\mathrm{id}}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\kernel}{\mathrm{null}\,}\)
\( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\)
\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\)
\( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)
\( \newcommand{\vectorA}[1]{\vec{#1}} % arrow\)
\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow\)
\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vectorC}[1]{\textbf{#1}} \)
\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)
\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)
\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Internal Structures of the Heart
The heart is divided into four chambers: right atrium, right ventricle, left atrium, and left ventricle. The atria are the two superior chambers of the heart and the ventricles are the two inferior chambers of the heart. The right side of the heart and the left side of the heart are isolated from each other (each belongs to a separate circuit - see the Circulation Through the Heart section below). The right and left sides are separated by septa. Between the right and left atria is tissue called the interatrial septum and between right and left ventricles is tissue called the interventricular septum.
Above: Chambers and valves of the heart.
|
Heart Chamber |
Location |
Blood flowing into this chamber |
Blood flowing out of this chamber |
Associated valves |
|---|---|---|---|---|
|
left atrium |
superior left side of the heart |
from pulmonary veins; oxygen-rich blood |
to the left ventricle |
mitral valve (aka left atrioventricular valve; aka bicuspid valve) drains blood from the left atrium when it is open during ventricular diastole |
|
left ventricle |
inferior left side of the heart |
from left atrium; oxygen-rich blood |
to the aorta |
blood moves into this chamber through the mitral valve (aka left atrioventricular valve; aka bicuspid valve) during ventricular diastole; blood moves out of this chamber through the aortic valve during ventricular systole |
|
right atrium |
superior right side of the heart |
from superior vena cava and inferior vena cava; oxygen-poor blood |
to the right ventricle |
tricuspid valve (aka right atrioventricular valve) drains blood from the right atrium when it is open during ventricular diastole |
|
right ventricle |
inferior right side of the heart |
from right atrium; oxygen-poor blood |
to the pulmonary trunk |
blood moves into this chamber through the tricuspid valve (aka right atrioventricular valve) during ventricular diastole; blood moves out of this chamber through the pulmonary valve during ventricular systole |
There are four valves in the heart: two that separate the atria from the ventricles on both the right and left sides (atrioventricular [AV] valves), and two that separate the ventricles from their associated arteries (aortic valve and pulmonary valve). The aortic valve and pulmonary valve are sometimes called semilunar valves since they are composed of three crescent-shaped cusps. The AV valves are also called the tricuspid valve and the bicuspid valve (aka the mitral valve); these names describe the number of cusps that make them up (tri= 3 cusps; bi= 2 cusps). Heart valves are either open or they are closed based on whether the heart muscle of the ventricles is contracting, ventricular systole, or the heart muscle of the ventricles is not contracting, ventricular diastole. Both systole and diastole are equally important for moving blood effectively though the heart and through the blood circulation circuits.
Above: Animated heart pumping with the ventricles shown open.
|
Heart Valve |
Location |
During ventricular systole |
During ventricular diastole |
How it Works |
|---|---|---|---|---|
|
aortic valve |
between the left ventricle and the aorta |
open |
closed |
valve is closed unless pressure inside the ventricle pushes it open |
|
mitral valve (left atrioventricular [AV] valve; bicuspid valve) |
between the left atrium and the left ventricle |
closed |
open |
valve is open unless pressure inside the ventricle pushes it closed; papillary muscles and chordae tendineae prevent the valves from flipping open during ventricular systole (prolapse) |
|
pulmonary valve |
between the right ventricle and the pulmonary trunk |
open |
closed |
valve is closed unless pressure inside the ventricle pushes it open |
|
tricuspid valve (right atrioventricular [AV] valve) |
between the right atrium and the left ventricle |
closed |
open |
valve is open unless pressure inside the ventricle pushes it closed; papillary muscles and chordae tendineae prevent the valves from flipping open during ventricular systole (prolapse) |
Above: Internal structures of the heart. (Left) Anterior view of the internal heart and (right) superior view of the valves of the heart with the atria removed.
|
Internal Heart Structure |
Location |
Function/Description |
|---|---|---|
|
chordae tendineae |
connecting the cusps of AV valves with the papillary muscles |
"heart strings" aid in holding AV valves closed to prevent valve from flipping open during ventricular systole |
|
fossa ovalis |
indentation in the right atrium along the interatrial septum |
location where a hole used to be during fetal development (foramen ovale); since fetal lungs are non-functional, the pulmonary circuit of circulation is extraneous and therefore blood is allowed to pass through foramen ovale from the right atrium to the left atrium; a flap closes over foramen ovale after birth and eventually seals up |
|
interatrial septum |
tissue between the right and left atria |
separate the right and left atria; keeps oxygen-poor blood on the right side of the heart from mixing with oxygen-rich blood on the left side of the heart |
|
interventricular septum |
tissue between the right and left ventricles |
separate the right and left ventricles; keeps oxygen-poor blood on the right side of the heart from mixing with oxygen-rich blood on the left side of the heart |
|
papillary muscles |
muscles on the internal heart wall connected to chordae tendineae |
aid in holding AV valves closed to prevent valve from flipping open during ventricular systole (prolapse) |
|
trabeculae carneae |
ridges along the inside wall of the ventricles |
aid in holding AV valves closed to prevent valve from flipping open during ventricular systole (prolapse) |
Above: (Right) Inside of the right atrium of the heart, superolateral view. (Left) Inside the left ventricle, anterior view.
Attributions
- "Anatomy 204L: Laboratory Manual (Second Edition)" by Ethan Snow, University of North Dakota is licensed under CC BY-NC 4.0
- "CG Heart.gif" by DrJanaOfficial is licensed under CC BY-SA 4.0
- "Heart Anatomy" by Dongho Kim is licensed under CC BY-NC-SA 4.0
- "Medical gallery of Blausen Medical 2014" by Blausen.com staff is licensed under CC BY 3.0