28 October 2008 Midterm grades: Test 1 (50%), quizzes (50%) Today: – Smooth muscle (Ch 9) – Control of body movement (Ch 10) Friday: begin Ch 12 cardiovascular physiology Lab this week: Frog Muscle # 1 (see website) – Runs 20 minutes over Abstract Due Date: Friday Nov 13 th check website for details Friday class demo of using SPSS

Chapter 9 B Properties of Smooth Muscle (Cardiac muscle covered later) How does smooth muscle differ from skeletal muscle? (innervation, membrane potentials, excitation-contraction coupling, twitch duration, fatigue, etc. (Table 9-6 p.292) What are the features of membrane potential of smooth muscle? (pacemakers and slow waves) What are the differences between single-unit and multi-unit smooth muscle? (location, spread of excitation)

Figure 9.34 Special situation: Dephosphorylation & latch bridge from SR and influx during Action Potential or graded potential Graded potentials result in graded contractions

latchbridge

Control of membrane potential by neurotransmitters, hormones, local factors for some smooth muscles (0 2, pH, stretch, vasodilators….) Know the locations of single-unit and multi-unit smooth muscles

Fig Know this table Except Cardiac Muscle for now End of material for Test # 2

Chapter 10: Control of somatic motor systems Riding a bike, playing piano, swinging a bat or golf club…. Begin material for Test # 3

Fig a

Somatatopy in Primary Motor Cortex

Fig Formerly called “basal ganglia”, consist of caudate, putatmen, and globus pallidus

Fig Reflex Decision to move Initiates motor command Coordinates secondary movements Balance and complex learned movements Pathways? Corticospinal and corticobulbar tracts Examples of motor disorders: Huntington’s Disease and Cerebellar Disorder

Local control Muscle spindle – Stretch receptor – Intrafusal muscle fiber What is their role? The stretch reflex… – Follow the reflex arc – Be able to differentiate function of afferent fibers, alpha motor neurons, and gamma motor neurons Spindle Afferent

Fig ab

Fig c Co-activation of alpha and gamma motoneurons insures that the stretch of muscle can be detected regardless of the initial length or state of contraction of that muscle.

Stretch Reflex Monosynpatic excitation of motoneurons of that muscle and synergistic muscles and polysynaptic inhibition of motoneurons to antagonistic muscles. Recall frog reflex lab and existence of spinal reflexes in single-pithed frogs. Also, example Christopher Reeve and patellar reflex.