Question

1.How do gap junctions and intercalated disks aid contraction of the heart?
2. Why do the cardiac muscle cells demonstrate autorhythmicity?

Answer 1

Answer:

Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and desmosomes. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next.

Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and desmosomes. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next.

Answer 2

The Answer is:

1.

Desmosomes and gap junctions are two components of the sarcolemma found in intercalated discs, which are crucial for the contraction of heart muscle.

•  The depolarizing current generated by cations that can go from cardiac muscle cell to next because gap junctions create pathways across adjacent cardiac muscle fibres.
• In cardiac muscle, this connection is known as electric coupling, and it enables fast action potential transmission and synchronised contractions of the entire heart.
• A syncytium is a primary component of contraction made up of these electrically interconnected heart muscle cells.
• Desmosomes make up the intercalated disc's remaining portion. During contractions of the heart, a desmosome, a type of cell structure, holds the ends of the muscle fibres together to prevent the cells from pulling apart.

2.

A distinguishing quality of cardiac muscle is autorhythmicity. Without any external stimuli, these cells may produce action potentials at a specific rate, which is how the heart beats constantly and regularly.

• While cardiac muscle has some traits in common both with skeletal muscle and smooth muscle, it also differs in several other ways.
• Pacemaker cells, which are specialised cardiac muscle cells which directly control heart rate, control the heart's contractions.
• Autorhythmicity is the name given to this quality. This cannot be accomplished by skeletal or smooth muscle.
• The pacemaker cells react to impulses from autonomic nervous system to accelerate or slow down the pulse rate, despite the fact that heart muscle cannot be regulated consciously.
• Additionally, the electrical impulses can react to several hormones that modify heart beat to regulate blood pressure.

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