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At around 18 to 19 days after fertilisation, the heart begins to form. The heart begins to develop near the head of the embryo in the cardiogenic area. [1] Following cell signalling, two strands or cords begin to form in the cardiogenic region [1] As these form, a lumen develops within them, at which point, they are referred to as endocardial ...
Intercalated discs are complex structures that connect adjacent cardiac muscle cells.The three types of cell junction recognised as making up an intercalated disc are desmosomes, fascia adherens junctions, and gap junctions.
The average cardiac output, using an average stroke volume of about 70mL, is 5.25 L/min, with a normal range of 4.0–8.0 L/min. [8] The stroke volume is normally measured using an echocardiogram and can be influenced by the size of the heart, physical and mental condition of the individual, sex, contractility, duration of contraction, preload ...
The first heart sound, or S 1, forms the "lub" of "lub-dub" and is composed of components M 1 (mitral valve closure) and T 1 (tricuspid valve closure). Normally M 1 precedes T 1 slightly. It is caused by the closure of the atrioventricular valves , i.e. tricuspid and mitral (bicuspid), at the beginning of ventricular contraction, or systole .
A syncytium (/ s ɪ n ˈ s ɪ ʃ i ə m /; pl.: syncytia; from Greek: σύν syn "together" and κύτος kytos "box, i.e. cell") or symplasm is a multinucleate cell that can result from multiple cell fusions of uninuclear cells (i.e., cells with a single nucleus), in contrast to a coenocyte, which can result from multiple nuclear divisions without accompanying cytokinesis. [1]
Thus, recording of approximately 1 minute is needed to assess the HF components of HRV (i.e., a lowest bound of 0.15 Hz is a cycle of 6.6 seconds and so 10 cycles require ~60 seconds), while more than 4 minutes are needed to address the LF component (with a lower bound of 0.04 Hz).
Pectoralis minor muscle (/ ˌ p ɛ k t ə ˈ r æ l ɪ s ˈ m aɪ n ər /) is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body.
The rectus abdominis muscle, (Latin: straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a pair of segmented skeletal muscle on the ventral aspect of a person's abdomen (or "midriff").