BIOS1171 Lecture Notes - Lecture 9: Golgi Tendon Organ, Tendon Reflex, Stretch Reflex

• School: University of Sydney
• Department: Biomedical Science
• Course: BIOS1171
• Professor: Jin Huang

Document Summary

Motor unit: single motor neuron + muscle fibre it innervates. Greater precision = less fibres by one neuron. Phasic firing: lmn innervates muscles quickly > cycle (contract > relax) Tonic firing: lmn maintains innervation of muscles constant. Recruits more motor neurons to innervate muscles. Vary in the contraction speed and speed of atp production (oxidative or glycolytic) Most muscles contain a mix of all 3 types (percentage determined by muscle usage) Slow fibres still contract while fast fibres are being recruited. Blood supply is red and has myoglobin (carries oxygen) Contractions are weak and slow but can be sustained over long periods. Poor blood supply = no oxygen > anaerobic metabolism. Can be oxidative (type 2a) or glycolytic (type 2x) Some oxidative capacity with fast twitch speed. Sustained contractio(cid:374)s = large recruit(cid:373)e(cid:374)t of (cid:373)otor u(cid:374)its (cid:894)he(cid:374)(cid:374)e(cid:373)a(cid:374)"s pri(cid:374)ciple(cid:895) He(cid:374)(cid:374)e(cid:373)a(cid:374)"s pri(cid:374)ciple: under load, motor units are recruited from smallest to larger.