CHAPTER 2: THORAX PART II: HEART Flashcards
What is Pericardium?
The pericardium is a fibroserous sac that encloses the
heart and the roots of the great vessels.
What is the function of pericardium?
Its function is to
restrict excessive movements of the heart as a whole and to serve as a lubricated container in which the different parts of the heart can contract.
Where does the pericardium lies?
The pericardium lies within the
middle mediastinum(Figs. 3.2, 3.30, 3.31, and 3.32),posterior to the body of the sternum and the 2nd to the 6th costal cartilagesandanterior to the 5th to the 8th thoracic vertebrae.
What are the types of Pericardium?
- Fibrous Pericardium
- Serous Pericardium
What is the fibrous pericardium?
The fibrous pericardium is the strong fibrous part of the
sac.
It is firmly attached below to the central tendon of the
diaphragm.
It fuses with the outer coats of the great blood
vessels passing through it (Fig. 3.31)—namely, the aorta, the pulmonary trunk, the superior and inferior venae cavae, and the pulmonary veins (Fig. 3.32).
The fibrous pericardium is attached in front to the sternum by the sternopericardial
ligaments.
What is serous pericardium?
The serous pericardium lines the fibrous pericardium and
coats the heart.
It is divided into parietal and visceral layers
(Fig. 3.31).
The parietal layer lines the fibrous pericardium and is
reflected around the roots of the great vessels to become
continuous with the visceral layer of serous pericardium
that closely covers the heart (Fig. 3.32).
What is serious pericardium?
It is divided into parietal and visceral layers
(Fig. 3.31).
The parietal layer lines the fibrous pericardium and is
reflected around the roots of the great vessels to become
continuous with the visceral layer of serous pericardium
that closely covers the heart (Fig. 3.32).
What does the parietal layer line?
The parietal layer lines the fibrous pericardium and is
reflected around the roots of the great vessels to become continuous with the visceral layer of serous pericardium that closely covers the heart (Fig. 3.32).
What is the visceral layer of the pericardium?
The visceral layer is closely applied to the heart and is
often called the epicardium.
The slitlike space between the
parietal and visceral layers is referred to as the pericardial
cavity (Fig. 3.31).
What is the normal amount of pericardial fluid?
Normally, the cavity contains a small
amount of tissue fluid (about 50 mL),the pericardial fluid, whichacts as a lubricant to facilitate movements of the heart.
What is the oblique sinus?
On the posterior surface of the heart, the reflection of the serous pericardium around the large veins forms a recess called the oblique sinus (Fig. 3.32).
What is the transverse sinus
Also on the posterior surface of the heart is the transverse sinus, which is a short passage
that lies between the reflection of serous pericardium around the aorta and pulmonary trunk and the reflection around the large veins (Fig. 3.32).
The pericardial sinuses form as a consequence
of the way the heart bends during development (see
page 91). They have no clinical significance.
How is the pericardial sinus formed?
The pericardial sinuses form as a consequence
of the way the heart bends during development (see
page 91).
They have no clinical significance.
Nerve Supply of the Pericardium
What nerve supplies the fibrous pericardium and the parietal layer of the serous pericardium?
The fibrous pericardium and the parietal layer of the serous pericardium are supplied by the phrenic nerves.
The visceral layer of the serous pericardium is innervated by?
The visceral layer of the serous pericardium is innervated by
branches of the sympathetic trunks and the vagus nerves.
Desrcibe the Heart.
The heart is a hollow muscular organ that is somewhat pyramid
shapedandlies within the pericardium in the mediastinum
(Figs. 3.33 and 3.34).
It is connected at its base to
the great blood vessels but otherwise lies free within the pericardium.
Surfaces of the Heart
The heart has three surfaces:
- sternocostal (anterior),
- diaphragmatic (inferior), and a
- base (posterior).
It also has an apex, which is directed downward, forward, and to the left.
What is pericarditis?
In inflammation of the serous pericardium, called pericarditis, pericardial fluid may accumulate excessively, which can compress
- *the thin-walled atria and interfere with the filling of the**
- *heart during diastole.**
This compression of the heart is called
cardiac tamponade.
What is cardiac tamponade?
This compression of the heart is called
cardiac tamponade.
Cardiac tamponade can also occur secondary to stab or gunshot wounds when the chambers of the heart have been penetrated.
The blood escapes into the pericardial cavity and can
restrict the filling of the heart.
What is pericardial friction rub?
Roughening of the visceral and parietal layers of serous pericardium
by inflammatory exudate in acute pericarditis produces
pericardial friction rub, which can be felt on palpation and heard through a stethoscope.
What is paracentesis?
Pericardial fluid can be aspirated from the pericardial cavity should excessive amounts accumulate in pericarditis.
This process
is called paracentesis.
The needle can be introduced to the
left of the xiphoid process in an upward and backward direction at an angle of 45° to the skin. When paracentesis is performed
at this site, the pleura and lung are not damaged because of the presence of the cardiac notch in this area.
What forms the sternocostal surface ?
The sternocostal surface is formed mainly by the
right atrium and the right ventricle,which areseparated from each other by the vertical atrioventricular groove
(Fig. 3.34).
- right border is formed by the right atrium;
- left border, by the left ventricle and part of the left auricle.
The right ventricle is separated from the left ventricle
by the anterior interventricular groove.
The anterior interventricular groove separates what?
The right ventricle is separated from the left ventricle
by the anterior interventricular groove.
What forms the diaphragmatic surface of the heart?
The diaphragmatic surface of the heart is formed
mainly by the right and left ventricles separated by the posterior interventricular groove.
The inferior surface of the right atrium, into which the inferior vena cava opens, also
forms part of this surface.
What forms the base or posterior surface of the heart?
The base of the heart, or the posterior surface, is formed
mainly by the left atrium, into which open the four pulmonary
veins (Fig. 3.35).
The base of the heart lies opposite the apex.
What forms the apex of the heart?
The apex of the heart, formed by the left ventricle, is
directed downward, forward, and to the left (Fig. 3.34).
It lies at the level of the fifth left intercostal space, 3.5 in.
(9 cm) from the midline.
In the region of the apex, the apex
beat can usually be seen and palpated in the living patient.
Note that the base of the heart is called the base because the heart is pyramid shaped; the base lies opposite the apex.
The heart does not rest on its base; it rests on its diaphragmatic
(inferior) surface.
Why is the base of the heart called as such?
Note that the base of the heart is called the base because the heart is pyramid shaped; the base lies opposite the apex.
- *The heart does not rest on its base; it rests on its diaphragmatic
(inferior) surface.**
The heart rest s on its base.
T or F
FALSE
The heart does not rest on its base; it rests on its diaphragmatic
(inferior) surface.
What are the Borders of the Heart?
Borders of the Heart
- right border: right atrium
- left border: left auricle
- below:left ventricle
(Fig. 3.34).
- The lower border is formed mainly by the right
ventricle but also by the right atrium;
- the apex is formed bythe left ventricle.
These borders are important to recognize when examining a radiograph of the heart.
Chambers of the Heart
- Right Atrium
- Right Ventricle
- Left Atrium
- Left Ventricle
What divides the heart into four chambers?
The heart is divided by vertical septa into four chambers: the right and left atria and the right and left ventricles.
The right atrium lies anterior to the left atrium, and the right ventricle lies anterior to the left ventricle.
What composes the walls of the heart?
The walls of the heart are composed of:
- cardiac muscle, :the myocardium;
- epicardium:covered externally with serous pericardium
- endocardium: and lined internally with a layer of endothelium
What consist right atrium?
The right atrium consists of a main cavity and a small outpouching, the auricle (Figs. 3.34 and 3.36).
What can you find on the outside of the right atrium?
On the outside
- vertical groove,
- the sulcus terminalis
- crista terminalis.
What is the main part of the atrium that lies posterior to the ridge?
The main part of the atrium that lies posterior to the ridge is smooth walled and is derived embryologically from the sinus venosus.
Describe the front of the atrium.
The part of the atrium in front of the ridge is roughened or trabeculated by bundles of muscle fibers, the musculi pectinati, which run from the crista terminalis to the auricle.
Where does the anterior part of the right atrium derived?
This anterior part is derived embryologically
from the primitive atrium.
What is sulcus terminalis?
On the outside
of the heart at the junction between the right atrium and the right auricle is a vertical groove, the sulcus terminalis,
What is the auricle?
The right atrium consists of a main cavity and a small outpouching, the auricle (Figs. 3.34 and 3.36).
What is crista terminalis?
On the outside
of the heart at the junction between the right atrium and the right auricle is a vertical groove, the sulcus terminalis, which on the inside forms a ridge, the crista terminalis.
