2 - CNS control of muscle contraction Skeletal Muscle Motor...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CNS control of muscle contraction Skeletal Muscle Motor cortex Motor axons Neuromuscular junctions Cardiac Muscle Autonomic nervous System modulation Bouton nerve endings Control of the heart by the autonomic nervous system Myocyte control of force Muscle cells involved in contraction Skeletal Muscle Fiber recruitment by motor cortex Cardiac Muscle All heart cells contract every time Systole and Diastole Motor Unit A collection of muscle fibers innervated by a single motor neuron … increase force by recruiting more motor units Frequency of stimulation Skeletal Muscle Motor cortex control of stimulation rate Cardiac Muscle Sinus (SA nodal) rhythm Pacemaker Heart rate (HR) ANS control of HR Frequency summation in skeletal muscles an increase in the frequency of contraction of a single motor unit Frequency summation of twitches and tetanus AP Myoplasmic [Ca2+] Fused tetanus Myocyte control of force Skeletal Muscle None Cardiac Muscle Contractility ANS control of contractility Control of the heart by the autonomic nervous system Load Skeletal Muscle Skeleton Opposing skeletal muscle External load Cardiac Muscle Blood Diastolic blood volume Preload Arterial blood Afterload Right and left branches of the heart Parallel circulatory beds Excitation Skeletal Muscle Ach EPP Cardiac Muscle AP Automaticity Pacemaker if SA node → Sinus rhythm Conduction Gap junctions junctions Excitation (cont.) Heart Automaticity Pacemaker if SA node → Sinus rhythm The cardiac cycle as a function of time The cardiac cycle as a function of time Jugular pressures a RA contraction c RV contraction (bulge of tricuspid valve v filling of RA against closed tricuspid ...
View Full Document

This note was uploaded on 12/03/2009 for the course PSL 431 taught by Professor Stephenson during the Spring '07 term at Michigan State University.

Ask a homework question - tutors are online