Motor unit
The motor unit.
A motor unit consists of a motor neuron and the muscle fibers it controls. The motor neuron sends signals to the muscle fibers to contract, while the motor unit refers to the combination of the neuron and the muscle fibers it innervates.
Skeletal muscle is made up of individual components known as muscle fibers. These fibers are formed from the fusion of developmental myoblasts (a type of embryonic progenitor cell that gives rise to a muscle cell). The myofibers (muscle fiber) are long, cylindrical, multinucleated cells composed of actin and myosinmyofibrils repeated as a sarcomere, the basic functional unit of the cell and responsible for skeletal muscle's striated appearance and forming the basic machinery necessary for muscle contraction. The term muscle refers to multiple bundles of muscle fibers held together by connective tissue. Wikipedia dude ...
There are approximately 642 skeletal muscles within the typical human, and almost refers to the action of each muscle from the standard anatomical position.
Contractile impulse refers to the electrical signal that initiates contraction in muscle cells. In cardiac muscle, this impulse originates from the sinoatrial (SA) node, propagating through the heart to coordinate rhythmic contractions. In skeletal muscle, it results from signals transmitted by motor neurons. Overall, contractile impulses are crucial for the effective functioning of both cardiac and skeletal muscles.
It consists of a maximum of 2 nuclei per fiber so no it can't be considered multinucleated. Only skeletal is multinuke.
Voluntary muscles vs involuntary muscles. Generally this refers to striated or skeletal muscles as opposed to the smooth muscle of the intestine or around blood vessels.
Myogenic muscle contractions are initiated by the muscle cells themselves without external neural stimulation, such as in the heart muscle. Neurogenic muscle contractions require neural input to initiate and control muscle activity, such as in skeletal muscles controlled by the somatic nervous system.
Smooth tissue refers to a type of tissue that lacks striation and is typically found in organs like blood vessels and the digestive tract. Muscle tissue encompasses three types: skeletal muscle, cardiac muscle, and smooth muscle. Smooth tissue is a specific type of muscle tissue known as smooth muscle tissue.
There are two ends of attachment of skeletal muscle. The "origin", and the "insertion". The "insertion" end refers to the end which is attached to a moveable bone which this muscle will move when it is contracted. The "origin" end is usually the most distal attachment (in appendicular skeleton) this is the bone that the muscle attaches to, and DOES NOT MOVE. Example. Biceps brachii. Origin- connection to the humeral head Insertion- radius/ulna summary- contract your biceps muscle, and your radius and ulna will move. not your shoulder. The end.
Motor neuron firing refers to the process by which motor neurons generate action potentials, leading to the transmission of signals from the nervous system to muscles. When a motor neuron receives sufficient stimulation, it depolarizes and fires an action potential, causing the release of neurotransmitters at the neuromuscular junction. This triggers muscle contraction, enabling movement. The frequency and pattern of motor neuron firing can vary based on the type of movement being performed.
Atrophy of skeletal tissue refers to the loss of muscle mass and strength due to lack of use or decreased physical activity. It can also occur as a result of aging, injury, or certain medical conditions. Atrophy can be reversed through physical exercise and rehabilitation programs designed to increase muscle mass and improve functional capacity.