Layers Of The Heart Flashcards
What three layers is the heart composed of?
Epicardium, myocardium and endocardium
Describe the epicardium (visceral pericardium)
The epicardium consists of a layer of connective tissue and produces a protective layer over the heart
Describe the myocardium
This is the muscular component of the heart wall, consists of Myocytes or cardiac muscle cells
Describe the endocardium
This layer of epithelium and connective tissue lines the heart and covers the heart valves. The endocardium is continuous with the endothelial lining of blood vessels
Describe cardiac muscle
It is only found in the heart, it is striated muscle but is not under voluntary control
What does the heart not require?
Doesn’t require direct stimulation from the nervous system
What does the contraction of the cardiac muscle rely on?
Relies on sliding filament mechanism between thick and thin muscle filaments of the sarcomeres
What is the difference between cardiac and skeletal muscle?
Cardiac muscle cells form a highly branched, interconnecting network of fibres
What does the heart operate as?
A functional syncytium
Describe functional syncytium
Means that an electrical stimulus to any on part of the heart can cause contraction of the whole myocardium
What are the cardiac cells physically divided by?
The sarcolemma
What are intercalated discs?
They separate the sarcoplasmic of adjacent cardiac muscle cells
How are the discs held together?
Through the action of desmosomes
How are electrical excitations passed through the cell?
By gap junctions
What is the cardiac muscle anchored to support?
The fibrous skeleton
