KIN 346 Ch. 3 Neural Control

Nervous System Overview

Discusses various components of the nervous system, emphasizing the role of receptors in collecting information.

Receptors

  • Function of Receptors:

    • Collect information from the environment, including sensory inputs like touch, sound, light, and chemical stimuli.

  • Pathway of Information:

    • Receptors send collected information to the brain via the central nervous system (CNS), which consists of the brain and spinal cord.

  • Interpretation by CNS:

    • The central nervous system processes and interprets this information, enabling an appropriate reaction or response to the stimuli.

Muscle Contraction

  • Understanding Muscle Contraction:

    • Important to have a clear concept of how muscles contract, which is essential for movement and physical activity. Muscle contraction involves complex biochemical processes within muscle fibers.

  • Muscle Action:

    • Muscles can perform both shortening (concentric contraction) and lengthening (eccentric contraction) actions during contraction, allowing for various movements.

Muscle Spindles vs. Golgi Tendon Organs

  • Muscle Spindles:

    • Detect changes in muscle length and the rate of that change, providing crucial information about stretch and facilitating reflex actions.

  • Golgi Tendon Organs:

    • Located at the junction between muscles and tendons, these organs respond to tension within the tendon and contribute to the regulation of muscle contraction, ensuring force is appropriately balanced.

Example: Elbow Movement

  • A practical example discusses the process of moving the elbow back to a 90-degree angle.

  • Recruitment of Muscle Fibers:

    • As the angle changes, more muscle fibers are activated to achieve the desired movement, demonstrating the principle of recruitment. This process is essential for smooth and controlled motion.

  • Tension Regulation:

    • Removing Tension Across the Tendon: Golgi tendon organs play a crucial role in preventing excessive tension, thus protecting muscles and tendons from injury.

  • Activation of Golgi Tendon Organ:

    • Increases during activities like bench pressing, signaling the muscle to relax and avoid injury when excessive tension is detected. This feedback mechanism is vital for maintaining safety during physical exertion.