Download THE HUMAN HEART

THE HUMAN HEART
I.
HUMAN HEART MODELS
A.
Introduction
You cannot understand the heart by studying only models; you must study
a real heart. However, heart models are useful to get the “lay of the land,”
and you will enjoy the sheep heart dissection much more if you are
familiar with the models. Our models have no keys, but the text
illustrations will serve as keys.
B.
External structures (Fig. 20.55) Use the heart models. Keep in mind that
when the vessel’s name is “pulmonary,” the color of the blood within is
opposite the usual. Always use “left” and “right” as given below.
Right atrium [plural is atria]
Right ventricle
Left atrium
Left ventricle
Right auricle
Left auricle (not shown on illustrations)
Pulmonary trunk
Right pulmonary artery
Left pulmonary artery
Aorta
Superior vena cava
Inferior vena cava
Right pulmonary veins
Left pulmonary veins
Coronary sulcus (groove that separates atria from ventricles)
Anterior interventricular sulcus
Posterior interventricular sulcus
C.
Internal structures (Fig. 20.7) Study the heart models.
Right atrium
Coronary sinus
Tricuspid valve
Papillary muscles
Right ventricle
22
23
Left Atrium
Bicuspid valve (mitral valve)
Left ventricle
Chordae tendineae
Interventricular septum
Pulmonary semilunar valve
Aortic semilunar valve
D.
Remnants of fetal structures. These structures were open to blood flow
before birth; they closed shortly after. They are not well shown on the
illustrations, but are easily seen on most heart models.
Fossa ovalis
Ligamentum arteriosum
E.
Heart wall and serous membranes (Fig. 20.3, 20.4) Use models except
as noted.
Parietal pericardium (illustration only)
Epicardium (Visceral pericardium)
Myocardium
Endocardium
F.
Blood flow through the heart (Fig. 20.10) Trace the pathway of blood
through these structures using a heart model. Know this sequence.
1.
Deoxygenated (“blue”) blood flows from
Superior and inferior vena cava and coronary sinus to
Right atrium, through
Tricuspid valve to
Right ventricle, through
Pulmonary semilunar valve to
Pulmonary trunk [artery] to
Alveoli of lungs
2.
Oxygenated (red) blood flows from
Alveoli of lungs to
Pulmonary veins (4) to
Left atrium, through
Bicuspid (mitral) valve to
Left ventricle, through
Aortic semilunar valve to
Aorta, to entire body except __________ ___ _________.
24
G.
Vessel definitions
Artery: takes blood away from the heart, no matter the color of the
blood
Vein: carries blood toward the heart, no matter the color
Systemic arteries: carry red blood to all parts of the body except
the alveoli of the lungs
Systemic veins: carry “blue” blood toward the heart from all parts
of the body except the alveoli of the lungs
Pulmonary arteries: carry “blue” blood from the right heart toward
the lungs. The pulmonary trunk is an artery
Pulmonary veins: carry red blood from lungs toward the left heart
Sinus: a large, thin-walled vein. All sinuses are found in the
systemic circulation; for example, the superior sagittal sinus of the
brain, or the coronary sinus of the heart.
25
II.
CORONARY CIRCULATION
A.
Introduction
This is the vital circulation to the heart muscle itself. The
illustrations show the vessels on the anterior and posterior side at
once, as if it were a transparent glass heart. The lighter color
shows more posterior vessels. The coronary arteries are the ones
that are replaced during “bypass” surgery. Use the heart models to
study these vessels. Our lab has only one model which opens to
show the left coronary artery, which is hidden because it runs
behind the pulmonary trunk. (Fig. 20.6)
B.
Left coronary artery and its two main branches:
Anterior interventricular artery
Circumflex artery
C.
Right coronary artery and its two main branches:
Posterior interventricular artery
Right marginal artery
D.
Coronary sinus and the main branches which form it. These drain blood
from the capillaries of the heart and return the “blue” blood to which
chamber?
Great cardiac vein
Middle cardiac vein
Small cardiac vein
E.
Pairings of the arteries and veins of the heart. It is typical for arteries,
veins, and nerves to run side-by-side throughout the body. In the heart,
which veins run along side the arteries listed below?
Anterior interventricular artery
1.
____________________
Posterior interventricular artery
2.
___________________
Right marginal artery
3.
___________________
26
Notes and Sketches