20 October 2010 This Week in Physiology: Lab: Sensory Physiology & Visual System Lectures: Ch. 9 Muscle Physiology Next Week in Physiology: Lab: Frog muscle physiology Lectures: Ch. 9 Muscle Physiology Approaching Fall Break!

Special Presentation Hosted by Alpha Epsilon Delta The Pre-Health Professions Society Wednesday, October 20th 6:00 pm, Milliken 122 (The Pit) a joint presentation by Wofford alumnus and professor Dr. Noel Brownlee and Director of Admissions at VCOM Mattie Bendall. Brownlee & Bendall will discuss the training and practices of osteopathic and allopathic physicians.

Special Presentation Dr. Barbara Morrison Director of the Medical Technology Program Palmetto Health Richland Describes the Medical Scientist Laboratory program and career opportunities in medical technology 11:00 a.m., Thursday, Oct.21, in RMSC 122 (The Pit).

Stimulus 1. If the stimulus is applied at the black bar, which sensory neuron will have the highest frequency of action potentials and why? 2. If the stimulus is applied at the black bar, which sensory neuron will have the lowest frequency of action potentials and why? 3. What happens at the region of the membrane indicated by the arrow? Four first-order sensory neurons with receptive membranes at bottom. 1QQ # 20 for 8:30 am

Stimulus 1QQ # 20 for 9:30 am Consider the four second-order sensory neurons (A- D) across the top of the diagram. Assume there are interneurons arranged in a typical pattern that interconnects these neurons. 1. If the stimulus is applied at the black bar, which 2 nd order neuron will have the highest frequency of action potentials and why? 2. If the stimulus is applied at the black bar, which 2 nd order neuron will have the lowest frequency of action potentials and why? A B C D

Characteristics: Location, cell shape, nuclei per cell, innervation, connections to adjacent myofibers, arrangement of actin and myosin, regulation of cross bridges, sources of Ca++, response to injury, etc. Different types of muscles for different tasks! S 1

S 2

Fig Synonyms: NMJ = neuromuscular junction Myoneural junction Motor end plate S 3

Fig AP in motor axon releases sufficient ACh for 1 AP in skeletal muscle. Nicotinic Myasthenia gravis and loss of nAChRs EPP S 4

Fig a Capillaries How does AP in sarcolemma cause twitch? Oxygen, Nutrients, hormones, waste S 5

Fig b Terms: Myofiber, myofibril, myofilament Thick myofilament = myosin Thin myofilament = actin S 6

Fig a S 7

Fig The concentration of free calcium is directly related to force of contraction in skeletal muscle Thus we need to understand the cellular mechanism of contraction… cell biology flashbacks… High fAP leads to accumulation of Ca++ in sarcoplasm because Ca++ ATPase doesn’t return all Ca++ to SR quickly enough. S 8