A motor unit consists of <u>a single motor neuron</u>.
<h3>What is a motor unit?</h3>
Most mature extrafusal skeletal muscle fibers in mammals are innervated by only a single alpha motor neuron. Since there are more muscle fibers by far than motor neurons, individual motor axons branch within muscles to synapse on many different fibers that are typically distributed over a relatively wide area within the muscle, presumably to ensure that the contractile force of the motor unit is spread evenly .
In addition, this arrangement reduces the chance that damage to one or a few alpha motor neurons will significantly alter a muscle's action. Because an action potential generated by a motor neuron normally brings to threshold all of the muscle fibers it contacts, a single alpha motor neuron and its associated muscle fibers together constitute the smallest unit of force that can be activated to produce movement.
Sherrington was the first to recognize this fundamental relationship between an alpha motor neuron and the muscle fibers it innervates, for which he coined the term motor unit.
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Answer:
Innate; adaptive
Explanation:
Immunity is the ability of an organism immune system to provide protection against pathogens. The immune system comprises of Innate and adaptive immune system.
The innate immune system is non-specific immune response to foreign substance and it comprises of physical barriers such as skin, chemicals and immune cells.
Adaptive immune response is specific immune response to particular antigen. It comprises mainly of T and B cells. In adaptive immune response the antibodies are produced and memory is created in exposure to specific antigen. So when next time that foreign antigen enters the body, it will produce the same specific immune response because of memory.
Answer:
These cells use active-transport systems in the apical domains of their plasma membranes to take up dietary sugars and amino acids from the lumen of the intestine. The uptake of glucose, for example, is carried out by a transporter that coordinately transports two Na+ and one glucose into the cell
Explanation:
Answer:
D. A periodic warming of sea surface temperatur
e.
Explanation:
Loggerhead turtles and Humboldt squids normally lives in the south coast of Mexican. These animals are sensitive to temperature. Due to warming waters during El Niño events, these animals migrated toward the North (coast of California).
PS: In the tropical eastern Pacific, if the sea temperatures rise 0.5 °C above the long-term average, the condition is declared as El Niño.
traditionally orange, but there are rainbow carrots that can be purple and yellow