9. The Muscular System Part 2

Skeletal muscle interface

• Tendons are responsible for sensing tension, stretching and proprioception.

• Golgi tendon organs send messages to the brain which relate to the stretch reflex and muscle length.

• We then receive inhibiting messages (pain) to prevent causing damage.

Located in the tendons, sense changes in the length of the tendon, so when the muscles exert force, it creates tension in the tendons. The _______ _______ _______ sense the changes and send this information to the spinal cord and brain.

(a)  

Located within muscles, sense when the muscle is stretched, it also stretches the ______ ______. The _______ inform the central nervous system (CNS) about changes in the length of individual muscles and the speed or rate of stretching.

(a)  

Unconscious movement sense, the body's sense of space and balance:

(a)  

Which of the following is true for joint proprioceptors?

• Joint proprioceptors are sensory nerve endings that provide information about the position of the body and its parts in space.

• They are located in the joint capsule, cruciate ligaments, and menisci.

• Joint proprioceptors help the body make sense of the positions of the different body parts even without the aid of vision and the strength and effort needed to move these parts.

• They provide information to the CNS about the position and movement of the joints.

The short term effects of exercise on muscle - 'acute response': Pt. 1 of 2

• Increase in temperature

• Increased demand for oxygen as energy

• Increased myoglobin stores in the muscle

• Increased carbon-dioxide production

The short term effects of exercise on muscle - 'acute response': Pt. 2 of 2

• Increased number and intensity of signals that are transmitted to the muscle

• Increased vascular recruitment and blood supply to working muscles

• Production of lactic acid during anaerobic

• Depletion of energy substrates such as creatine phosphates and glycogen

The long term effects of exercise on muscle - 'chronic adaption': Pt. 1 of 2

• Increased capacity of the anaerobic glycolysis system to produce energy

• Increased muscular stores of ATP and CP

• Increased myoglobin stores in the muscle

• Increase in the intermyofibrilla mitochondria

The long term effects of exercise on muscle - 'chronic adaption': Pt. 2 of 2

• Depletion of energy substrates such as creatine phosphate and glycogen

• Increase lactate tolerance preventing the onset of fatigue

• Increased size and strength of ligaments and tendons

• Increased strength and cross-sectional size/area of muscle (hypertrophy)

Changes to the skeletal muscle over a lifespan Pt. 1 of 2

• There is a reduction in muscle mass (sarcopenia) of around 3-8% every decade past 30 years of age

• There is a loss of muscle fibres

• There is a decreased density of capillaries in muscle

• There is an increased time for muscle to contract in response to nervous stimuli