biology

Motor system

Motor system is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Motor system rather than just read about it. In short: The motor system is the set of central and peripheral structures in the nervous system that support motor functions, i.e. movement. Peripheral structures may include skeletal muscles and neural connections with muscle tissues.

Key takeaways

Motor system belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Motor system to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Motor system from memory before moving on to harder problems.

Reference excerpt

The motor system is the set of central and peripheral structures in the nervous system that support motor functions, i.e. movement. Peripheral structures may include skeletal muscles and neural connections with muscle tissues. Central structures include cerebral cortex, brainstem, spinal cord, pyramidal system including the upper motor neurons, extrapyramidal system, cerebellum, and the lower motor neurons in the brainstem and the spinal cord. The motor system is a biological system with close ties to the muscular system and the circulatory system. To achieve motor skill, the motor system must accommodate the working state of the muscles, whether hot or cold, stiff or loose, as well as physiological fatigue.

Pyramidal motor system

The pyramidal motor system, also called the pyramidal tract or the corticospinal tract, start in the motor center of the cerebral cortex. There are upper and lower motor neurons in the corticospinal tract. The motor impulses originate in the giant pyramidal cells or Betz cells of the motor area; i.e., precentral gyrus of cerebral cortex. These are the upper motor neurons (UMN) of the corticospinal tract. The axons of these cells pass in the depth of the cerebral cortex to the corona radiata and then to the internal capsule, passing through the posterior branch of internal capsule and continuing to descend in the midbrain and the medulla oblongata. In the lower part of the medulla oblongata, 90–95% of these fibers decussate (pass to the opposite side) and descend in the white matter of the lateral funiculus of the spinal cord on the opposite side. The remaining 5–10% pass to the same side. Fibers for the extremities (limbs) pass 100% to the opposite side. The fibers of the corticospinal tract terminate at different levels in the anterior horn of the grey matter of the spinal cord. Here, the lower motor neurons (LMN) of the corticospinal cord are located. Peripheral motor nerves carry the motor impulses from the anterior horn to the voluntary muscles.

Extrapyramidal motor system

The extrapyramidal motor system consists of motor-modulation systems, particularly the basal ganglia and cerebellum. For information, see extrapyramidal system.

See also Motor skill Motor control Motor disorder

References

External links Media related to Motor systems at Wikimedia Commons

Worked examples

Example 1 — a first encounter with Motor system

Start with the simplest possible case. Write down what Motor system claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Motor system before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Motor system ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Motor system

In research: Motor system appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Motor system in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Motor system is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anatomy, Motor control, Motor system, so understanding it makes those chapters shorter.
In everyday life: Look for Motor system outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Motor system in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Motor system means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Motor system out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Motor system in simple terms?

Why does Motor system matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Motor system?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Motor system.