Topic 10: Skeletal Muscle Physiology - Whole Muscle Contraction Flashcards
What are the 2 types of whole muscle contraction?
- Isotonic
- Isometric
What occurs in isotonic muscle contraction? (3)
- muscle changes length
- tension (relatively constant) exceeds the resistance of the load lifted
- uses ATP
Give an example of isotonic contraction (2)
- flexion at the elbow
- tension > weight of forearm
What occurs in isometric contraction? (4)
- muscle length is constant
- tension is less than required to move load
- tension increases, then cross bridges form but no shortening
- uses ATP
What type of contraction is lifting a book an example of? (3)
muscle - biceps brachii
- isotonic to lift
- isometric to hold
What is muscle metabolism?
- energy for contraction
What is muscle metabolism energy used for? (3)
- During resting conditions
- During Short term exercise (less than a min)
- Long term exercise (over a min to hours)
What occurs in muscle metabolism during resting conditions?
- fatty acids used to produce ATP (aerobic)
- storage of glycogen and creatine phosphate (C∼P)
What process creates creatine phosphate?
ATP + Creatine -> ADP + C∼P
note that it is a high energy bond
reaction can occur the other way too (short term exercise)
What occurs in muscle metabolism during short term exercise, like sprinting? (4)
- primarily anaerobic
- uses available ATP
- C∼P used to produce ATP (lasts 15b sec)
- muscle glycogen to lactic acid
What is the pathway from muscle glycogen to lactic acid? (5)
- Muscle Glycogen
- glucose
- Pyruvic acid
- Anaerobic pathway
- Lactic Acid
lasts 30 sec
What occurs in the muscle metabolism during long term exercise? (5)
- ATP from aerobic pathway
- glucose from liver
- fatty acids used more as exercise continues
- oxygen sources are blood hemoglobin and muscle myoglobin
- Can sometimes be anaerobic
