For sophomores and juniors interested in medical school and undergraduate opportunities: A visit by Dr. Paul Catalana, Al Squire, and other guests from Greenville Hospital System University Medical Center. In RMSC 122 (The Pit) starting at 6:30pm, Tuesday Oct 30th. Presentation and discussion on the new medical school at Greenville and undergraduate opportunities through their MedEx program, including clinical experiences and preparation for medical school.

Saturday Afternoon, Oct 27 Sunday, Oct 28 in Acorn Cafe Abstract due Monday At start of class. Abstract Reviewers Schedule Thursday, Oct 25 Friday, Oct 26 Saturday Afternoon, Oct 27 Sunday, Oct 28 in Acorn Cafe 9-11 am Biology Office Suite with Sharon Guffy 1-2 pm Biology Office Suite Miranda Stockman and Brooks Owens by appointment with Polly Ketcham ketchampd@email.wofford.edu 10-10 with Sejal Naik 12- 2 with Miranda Stockman 2-4 with Polly Ketcham 4-6 with Brooks Owens 6-8 with Becca Bryson

1QQ # 20 for 10:30 Write each letter, and circle each correct response. A person who trains to participate in the Tour de France would naturally acclimate by a) increasing the number of Type I myofibers b) increasing the density of capillaries in leg muscles c) synthesizing much more creatine than normal d) Converting Type II glycolytic fibers to Type II oxidative/glycolytic fibers. e) Synthesizing more thick and thin myofilaments in Type II myofibers.

1QQ # 20 for 11:30 Write each letter, and circle each correct response. A person who trains to compete in weightlifting would naturally acclimate by a) increasing the number of Type I myofibers b) increasing the density of capillaries in chest and arm muscles c) synthesizing much more thick and thin myofilaments in Type II myofibers d) Converting Type II glycolytic fibers to Type II oxidative/glycolytic fibers. e) Increasing the number of mitochondria in Type I myofibers of the chest and arm.

S 15 But each motor unit has myofibers of the same type: I or IIA or IIB.

Fig. 09.26 S 17 Relationship between recruitment and motor unit type The Size Principle Size of somatic motoneuron cell body 09.26.jpg

Increasing tension in a whole muscle Frequency of stimulation of motor neuron Recruitment: activate more motor units Activate larger motor units These factors also influence actual tension Fiber length (length-tension) relationship Fiber diameter Level of fatigue (state of activity)

Length-tension Relationship 09.21.jpg So….. Tension produced by a single myofiber varies depending on sarcomere length.

Types of Contractions S 6 Isotonic = Same tension Isometric = Same length Aka Lengthening contraction

S 9 Consider blood flow to skeletal muscles during isometric contractions. Consider blood pressure during isometric contractions.

Are there benefits of using trekking poles?

Who cares about smooth muscles? Chapter 9 B Properties of Smooth Muscle How does smooth muscle differ from skeletal muscle? (innervation, membrane potentials, excitation-contraction coupling, twitch duration, fatigue, etc. (Table 9-6 p.287) 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) Who cares about smooth muscles?

Two layers of smooth muscle in intestine

Classifying smooth muscle By location vascular gastrointestinal urinary respiratory reproductive ocular By contraction pattern Phasic: periodic contraction and relaxation Ex: esophagus and intestine Tonic: continuously contracting to some degree Ex: esophageal and urinary sphincters, vascular

Classifying smooth muscle continued. By communication with neighboring myofibers Single-unit smooth muscle: gap junctions with neighbors (function as a group) Ex: intestines Multi-unit smooth muscle: no gap junctions (myofibers function independently) Ex: Iris and ciliary muscle of the eye Interesting phenomenon: Uterine smooth muscle is multi-unit until just before labor and delivery when genes for gap junctions are expressed and the uterus become single-unit.

Comparison of Single-Unit and Multi-Unit Smooth Muscles S 13 Slow waves and pacemaker potentials Intestinal tract, uterus, small diameter blood vessels Large airways of lungs, large arteries, ciliary muscle Often with pacemaker cells Control by neurotransmitters, hormones, local factors for some smooth muscles (02, NO, pH, stretch, vasodilators ….)

Graded potentials result in graded contractions Excitation-contraction coupling in Smooth Muscles Figure 9.34 S 11 from SR and influx during Action Potential or graded potential Ca++ Graded potentials result in graded contractions Slow twitch of SM due to slow action of myosin ATPase. Lack troponin Special situation: Dephosphorylation & latch bridge

Comparison of Twitch Duration Latchbridge =latch state Thankful for latch state! Crucial for long-term tension of sphincters.

S 14 Cardiac Myofibers Intercalated Discs: mechanical attachments of cardiac myofibers to each other, with gap junctions (electrical synapses) to conduct AP Analogy: Falling dominoes

S 15 Plateau phase

S 16 Why no tetanic contractions of cardiac muscle?

Figure 12.17 S 17 Excitation-Contraction Coupling Calcium-induced calcium release What ends the twitch? Ca++ channels blockers: How and where do they work? When are they used?

S 18 Fig. 09.06 Know this table p. 287 09.06.jpg