1. 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.

2. 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
10-10 with Sejal Naik with Miranda Stockman 2-4 with Polly Ketcham 4-6 with Brooks Owens 6-8 with Becca Bryson

3. 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.

4. 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.

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

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

7. 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)

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

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

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

11. Are there benefits of using trekking poles?

12. 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?

13. Two layers of smooth muscle in intestine

14. 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

15. 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.

16. 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 ….)

17. 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

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

19. 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

20. S 15
Plateau phase

21. S 16
Why no tetanic contractions of cardiac muscle?

22. 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?

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