MUSCLE SYSTEM (Sliding Filament & Neuromuscular)

Front

What are myofibrils?

Back

Myofibrils are long, cylindrical structures found within muscle cells that contain the contractile proteins actin and myosin, essential for muscle contraction.

Front

What type of muscle tissue is smooth muscle?

Back

Smooth muscle is a type of non-striated muscle tissue that lines hollow organs such as blood vessels and the stomach, and is involuntary.

Front

What is the motor end plate?

Back

The motor end plate is a specialized region of the muscle fiber membrane at the neuromuscular junction where the motor neuron communicates with the muscle cell.

Front

What is actin?

Back

Actin is a thin myofilament protein found in muscle fibers that plays a crucial role in muscle contraction by interacting with myosin.

Front

What is the I Zone/Band in a sarcomere?

Back

The I Zone/Band is the region of a sarcomere that contains only thin filaments (actin) and appears lighter under a microscope.

Front

What is the role of myosin in muscle contraction?

Back

Myosin is a thick myofilament protein that interacts with actin to produce muscle contraction through a process called the sliding filament theory.

Front

What is the sliding filament theory?

Back

The sliding filament theory explains how muscle contraction occurs when actin and myosin filaments slide past each other, shortening the sarcomere.

Front

What is a sarcomere?

Back

A sarcomere is the basic functional unit of a muscle fiber, defined as the segment between two Z lines, containing both actin and myosin.

Front

What is the function of the synaptic cleft?

Back

The synaptic cleft is the small gap between the motor neuron and the muscle fiber where neurotransmitters are released to initiate muscle contraction.

Front

What is the role of calcium ions in muscle contraction?

Back

Calcium ions are released from the sarcoplasmic reticulum and bind to troponin, causing a conformational change that allows myosin to bind to actin.