The
heart is found in the center of the
thoracic cavity. It pumps the
blood through the circulatory
system allowing the circulation of nutrients, gases, wastes and other substances.
Heart tissues
The
superficial layer of
heart tissue is the
pericardium. The
deep layer of the
pericardium is the
serous pericardium consisting of a
visceral layer that clings tightly to the
myocardium and a
parietal layer that connects the
heart to the
fibrous pericardium. The most
superficial layer of the
pericardium is the
fibrous pericardium which is composed of fibrous
connective tissue and keeps the
heart securely in place in the chest by connecting to other
tissues.
The
heart is composed of mostly
cardiac muscle, which makes up the middle layer of
heart tissue called the
myocardium. The
myocardium is thickest at the
left ventricle and thinnest at the
atria. The
left ventricle must pump with enough force to push the
blood through the entire
systemic circuit. The
atria only need to exert enough force to push the
blood into the
ventricles.
The
deepest layer of
heart tissues is the
endocardium, which is a delicate layer of very smooth
epithelial tissue that makes up the walls of the
heart chambers.
Heart chambers
The
heart consists of four chambers:
Activity 11.1 - Anatomy of the Heart
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1 - Anatomy and Physiology Basics