KINS 2203 Chapter 1 Day 2 PDF

KINS 2203 Chapter 1: Day 2 Please note we will be using Poll Everywhere today…no need to register, and these are not for credit. My advice would be to put your phone on Do Not Disturb while we do these activities so that you can stay present, focused, and undistracted; I will try to remind you a...

KINS 2203 Chapter 1: Day 2 Please note we will be using Poll Everywhere today…no need to register, and these are not for credit. My advice would be to put your phone on Do Not Disturb while we do these activities so that you can stay present, focused, and undistracted; I will try to remind you at the end of class to turn it off again  While we are waiting for class to begin… Rank these components of a muscle from outside to inside Please get out your phones for a Poll Everywhere question  Active Learning: ways to study My best advice to college  Many ways to learn, many theories as to how many ‘types’ students: Figure out how you learn best.  Some include:  1. Visual (spatial) Learners How to do that? Try different  2. Aural (audio) Learners methods of studying for lower  3. Physical (tactile) Learners stakes assignments (to figure out what works for that particular  4. Verbal Learners (aka Linguistic Learners) class for you)  5. Logical (analytical) Learners  6. Social Learners (aka Linguistic Learners)  7. Solo Learners  8. Natural/ Nature Learners And good news! Our active learning activities in class are  Most people are a mix of several some methods you can try! https://www.viewsonic.com/library/education/the-8-learning-styles/  A reminder that not every activity we do in class is going to ‘work’ for every person every time. This means you may need to review some concepts outside of class to keep up Find what does work for you, and if you need help, ask me!  Review: Skeletal Muscle Organization Remember a muscle fiber is a muscle cell The patterns we see on a microscope are caused by the protein filaments that compose a sarcomere  We will focus on five (six) specific protein filaments: 1. Actin 2. Myosin 3. Titin 4. Tropomyosin 5. Troponin 6. (Nebulin: “anchoring protein” that stabilizes actin) Myosin thick filaments contain lots of myosin heads Image from: https://basicmedicalkey.com/wp-content/uploads/2016/06/m_jans1_c012f003c.png  Let’s create a sarcomere with pipe cleaners! 1. M-line 5. Elastic filament (titin) 2. Thick filament (myosin) 6. A-Band 3. Z-disc 7. I-Band (contraction changes its size) 4. Thin filament (actin) 8. H-Band 5. Zone of overlap  The role of titin Stack your wrists on top of one another with your elbows pointing laterally…WITHOUT bending your wrists or separating your arms, how can you move your elbows closer together? Introduction to sliding filament theory Sliding filament theory  No protein filaments change their length; they slide over each other to shorten or lengthen the length of the sarcomere So how does this ‘sliding’ of filaments occur? Cross-bridge cycling  Quick Review: ATP, ADP, and Pi ATP = adenosine triphosphate ADP = adenosine diphosphate Pi = inorganic phosphate phosphate removed  ADP + Pi + energy  ATP  ATP  ADP + Pi + energy  Purpose: to power cellular processes (4) Cross-bridge cycling  Cross-bridge: when myosin heads contact actin  The possible contact points on the actin filaments are called “myosin binding sites” because that is where the myosin can bind to create the cross-bridge  Power stroke: when the already bound myosin head pulls (also called rachets) the actin filament, causing the slide  Cross-Bridge Cycling Figure 50.28 from Campbell’s Biology Cross-Bridge Cycling When can the myosin heads bind? Troponin, Tropomyosin, & Actin Image from: https://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/14723328/f5_lehman_fig5.jpg AP FLIX: Muscle Contraction Part 3: The Cross Bridge Cycle (4-minute video) Test your knowledge on your own!  Where is each protein type located and which/how does it interact with? 1. Actin 2. Myosin 3. Titin 4. Tropomyosin 5. Troponin 6. (Nebulin) Excitation-contraction coupling, so far… Image from: https://www.researchgate.net/publication/2795098 49/figure/fig2/AS:669551918338055@1536645025514 /4-Excitation-contraction-coupling-1-An-action- potential-arrives-at-the-neuromuscular.ppm Are all muscle fibers the same? No! Current research in exercise science Overview of Muscle Fiber Types  Type I muscle fibers: slow  Type II muscle fibers: fast  Type IIa: most frequently recruited  Type IIx:  Type IIc: difficult to recruit  Differences between them not well understood, especially IIx Welcome to our game show: Which fiber type is that! ‘Where do you stand’ hand-raising activity GAME SHOW! Which fiber type is that? Type I = raise your LEFT hand Type II = raise your RIGHT hand  HINT: Structure relates to function! 1. Has a faster myosin ATPase compared to the other fiber type 1. Type II (fast twitch) 2. Has a highly developed SR compared to the other fiber type 2. Type II (fast twitch) 3. A motor unit of this kind innervates less than 300 fibers 3. Type I (slow twitch) 4. A motor unit of this kind reaches peak tension faster and 4. Type II (fast twitch) collectively generates more force compared to the other type 5. Type I (slow twitch) 5. Recruited for low-intensity endurance movements 6. Type I (slow twitch) 6. Lower peak power generated 7. Type II (fast twitch) 7. More efficient at anaerobic metabolism (none oxygen) 8. Type II (fast twitch) 8. A motor unit of this kind tends to have larger-sized fibers  Summary of fiber type comparison Type I fibers Type II fibers  Its myosin ATPase works slowly  Its myosin ATPase works quickly  Therefore, contracts slower  Therefore, contracts faster  Less developed sarcoplasmic reticulum  More developed sarcoplasmic reticulum  Tend to be smaller, with less fibers  Tend to be larger, with more fibers  Smaller α-motor neuron cell body  Larger α-motor neuron cell body  Innervates 300 muscle fibers  Reach peak tension more slowly  Reach peak tension more quickly  Collectively generate less force  Collectively generates more force  High aerobic endurance  Higher anaerobic capacity  Efficient making ATP from carbs and fat  Efficient at using anaerobic pathways  Recruited mostly for low-intensity mvts  Recruited for shorter high-intensity mvts HOWEVER!  Type I fibers can have Type II ATPase  Type II fibers can have Type I ATPase Think of this feature as a continuum So, where can we find these fibers? Can we change the ratio of them through training? Distribution and determination of fiber types  Distribution of fiber types  The amount per person does vary  Distribution of fiber types is similar for arms and legs within the same person  “Endurance athletes who have predominantly type I fibers in their legs will likely have a high percentage of type I fibers in their arms as well.” p. 41  Exceptions exist, such as the soleus (high type I in everyone)  Determination of fiber types  Determined very early in life  Genes determine α–motor neurons  Which then determine fiber type  Training can shift