Chapter 2 Neuromuscular System - Key Concepts Flashcards

Flashcards covering neuromuscular basics from muscle naming, fiber architecture, contraction types, innervation, proprioception, and fundamental motor control concepts.

What two types of muscles are mentioned, and which type does this course focus on?

Skeletal muscles and smooth (involuntary) muscles; the course focuses on skeletal muscles.

What is dynamic stability in the context of movement?

Stabilization provided by muscles during movement to enable safe, efficient, and controlled motion.

Which muscle type helps maintain posture due to its endurance and slow-twitch characteristics?

Postural muscles (slow-twitch) that hold us upright and provide endurance for long periods.

Approximately how many muscles are in the human body, and how many pairs work on opposite sides?

About 600 muscles total; about 215 pairs of muscles that work together on opposite sides (agonist-antagonist pairs).

What are the common criteria used to name muscles?

Shape, location, and function (also heads, direction, attachments, and action).

Give an example of a fusiform muscle and its functional characteristic.

Brachialis or biceps brachii; fusiform parallel shape with a thick belly (gaster) and narrow tendons at each end, optimized for length/ROM.

What is a strap muscle, and why is it useful?

A long, rectangular parallel muscle with relatively uniform width; supports a long range of motion and focused action (example: sartorius).

What is a radiate (triangular) muscle and how does it function?

A muscle with a broad origin that converges to a single insertion, concentrating force at a specific point (e.g., pectoralis major).

What does a bipennate muscle arrangement imply about force production?

Fibers arranged on both sides of a central tendon; more fibers in cross-sectional area, enabling greater force (e.g., rectus femoris, flexor hallucis longus).

How does cross-section diameter relate to a muscle's force production?

Greater cross-sectional diameter generally allows greater force production; longer muscles provide more ROM.

Which fiber arrangement is best for producing length and ROM, and which for strength?

Parallel fibers produce length/ROM; pennate fibers (unipennate, bipennate, multipennate) produce greater strength due to more fibers in a given area.

Name three parallel fiber muscle shapes and give an example for one.

Fusiform (example: brachialis), Strap (example: sartorius), Radiate (example: trapezius/pectoralis major). Note: radiate is triangular, not parallel.

What does the term 'gaster' refer to in a muscle?

The belly or central, thick part of a muscle where most fibers run.

What is the difference between origin and insertion, and which is considered proximal?

Origin is the proximal attachment; insertion is the distal attachment; origin is the closest to the body's midline.

What does aggregate muscle action mean in movement analysis?

Most movements involve many muscles firing together (agonists, antagonists, stabilizers, synergists) rather than a single muscle.

In elbow flexion, which muscle is the agonist and which muscles are common synergists or stabilizers?

Agonist: biceps brachii; synergists include brachialis/brachioradialis; stabilizers fix the scapula to provide a stable base.

What is an antagonist in kinesiology, and how does it interact with the agonist?

A muscle on the opposite side of a joint that relaxes to allow the agonist to move and can contract to produce the opposite action.

What are stabilizers (fixators) and why are they important?

Muscles that stabilize joints to provide a solid base for movement (e.g., scapular or hip stabilizers).

What is a neutralizer in muscle action?

A muscle that counteracts another muscle to cancel out unwanted movement (e.g., supinating with biceps while triceps stabilizes the elbow).

What is a force couple in movement biomechanics?

Two or more muscles pulling in different directions to produce a smooth rotation or lift (e.g., trapezius and serratus anterior during upward rotation of the scapula).

What is active insufficiency versus passive insufficiency?

Active insufficiency: a muscle shortens to the point it cannot shorten further; Passive insufficiency: a muscle is stretched to a length where it cannot lengthen further.

What is the stretch-shortening cycle and why is it important for performance?

Stretch the muscle to store elastic energy, then rapidly shorten to produce greater force; a key mechanism in plyometrics.

What are muscle spindles and Golgi tendon organs, and what do they do?

Muscle spindles: detect stretch and speed of length change, triggering reflexive contraction; Golgi tendon organs: detect excessive tension and trigger relaxation of the muscle to protect joints.

What are Pacinian corpuscles, Ruffini endings, and Meissner's corpuscles, in simple terms?

Cutaneous proprioceptors: Pacinian (pressure), Ruffini (deep pressure and joint position), Meissner (light touch) that contribute to kinesthetic awareness.

What does isokinetic movement mean, and what is it used for?

Movement at a constant speed, typically measured with specialized equipment to assess torque and muscle balance.