Muscles, Protection, Support, and Movement Tristan Beasley-Painter and Nicholas Ravn

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Transcript of Muscles, Protection, Support, and Movement Tristan Beasley-Painter and Nicholas Ravn

  • Slide 1
  • Muscles, Protection, Support, and Movement Tristan Beasley-Painter and Nicholas Ravn
  • Slide 2
  • Structures to be Discussed Bones Muscles Ligaments Tendons Joints Nerves
  • Slide 3
  • Bones
  • Slide 4
  • Role of Bones Provide a rigid structure to support body o Humans have an "endoskeleton" rather than an "exoskeleton" like arthropods; no molting needed Protects vital internal organs o Skull protects brain, rib cage protects heart and lungs, vertebrae protect spinal cord Provides sites for muscle attachment An important storage reservoir for ions o All bones have a matrix of calcium phosphate Produces blood cells o Blood cells and blood elements produced in red bone marrow in skull, ribs, sternum, pelvis, and long bones
  • Slide 5
  • Bones (cont.) Born with about 350 bones; fuse to form around 206 by adulthood http://www.teach pe.com/images/ anatomy/skeleto n.jpg
  • Slide 6
  • Invertebrate Skeletons Cnidarians, flatworms, roundworms, and annelids have a hydrostatic skeleton o Gastrovascular cavity or fluid-filled coelom Resist muscle contraction, resulting in movement Analogous to a garden hose stiffening when water flows through Allows organism to move and change shape http://www.emc.maric opa.edu/faculty/farab ee/biobk/hydroskel2. gif
  • Slide 7
  • Invertebrate Skeletons (cont.) Molluscs and arthropods typically have exoskeletons (external skeletons) o Composed of calcium carbonate (molluscs) or chitin (arthropods) Provide protection and muscle attachment points like an internal skeleton Strength improved through thickness o Decreases available space for internal organs Exoskeleton of mollusc grows with organism Arthropods must molt when exoskeleton becomes too small o Suffer a period when new one must dry and form
  • Slide 8
  • Nonliving Exoskeletons The exoskeletons of molluscs and arthropods are nonliving o Mollusc shells grow with the organism, but are still acellular Grow through secretion of more material by organism Arthropods have exoskeleton of chitin (a nitrogenous polysaccharide) o Produced and dried once; does not continue growing with organism Arthropods must molt as a result
  • Slide 9
  • Nonliving vs. Living Skeletons Echinoderms and vertebrates have endoskeletons Echinoderms' are nonliving o Composed of spicules and plates of calcium carbonate embedded in living tissue Vertebrates' are living tissue o Offers many benefits Grows with organism, molting not required Supports high weight without limiting space Protected by external soft tissue Jointed, allowing complex movements
  • Slide 10
  • Vertebrate Skeleton Two components of the vertebrate skeleton: o Axial skeleton o Appendicular skeleton http://upload.wikimedia.org/wikipedia/commons/ thumb/8/8b/Axial_skeleton_diagram.svg/250px- Axial_skeleton_diagram.svg.png http://en.wikipedia.org/wi ki/File:Appendicular_ske leton_diagram.svg
  • Slide 11
  • Axial Skeleton Lies in middle of the body o Skull, vertebral column, thoracic cage, sacrum, coccyx Total of 80 bones Skull protects brain o Cranium and facial bones Cranium bones have same names as lobes of the brain (for those psychology students out there) Vertebral column supports head and trunk and protects the spinal cord o Directly or indirectly serves as an anchor for all other bones of the skeleton
  • Slide 12
  • Axial Skeleton (cont.) The thoracic vertebrae are those that are part of the thoracic cage (rib cage) The sacrum and coccyx are at the end of the spine and attach to the pelvis
  • Slide 13
  • Bone Growth/Remodeling Bone consists of both living tissue and nonliving material The living tissue includes blood vessels, nerves, collagen Important to growth are osteoblasts (form bone) and osteoclasts (remove old bone) o Osteoclasts form in small concentrations to remove an area of the bone o Osteoblasts form next, laying down new bone material over months (affected by nutrition, age, etc.) This process begins to slow around age 40, leading to more brittle bones Deterioration of osteoblasts leads to osteoporisis
  • Slide 14
  • Muscles
  • Slide 15
  • Role of Muscles Three types of muscle tissue in humans: o Smooth o Cardiac o Skeletal Skeletal muscle (striated voluntary muscle) is probably of greatest obvious importance to most people o Important in maintaining posture o Provides support o Allows movement o Maintains homeostasis/body temperature Contraction causes ATP breakdown and releases heat throughout the body
  • Slide 16
  • Muscles (cont.) Around 700 skeletal muscles 40% of weight of average human http://en.wikipedia.org/wiki/Mu scle
  • Slide 17
  • Vertebrate Muscles' Macroscopic Functions and Physiology - Muscle cells are quite unique, resulting in them being called muscle fibers - They have the normal parts of a cell along with special components - Skeletal muscles are muscle fibers in bundles - The sarcolemma, or plasma membrane, forms a T (transverse) system. The T tubules penetrate, or dip down, into the cell so that they come into contact (but do not fuse) with expanded portions of modified endoplasmic reticulum, called the sarcoplasmic reticulum. - Store calcium ions - SR encases myofibrils - what contracts the muscle
  • Slide 18
  • Macroscopic Physiology (cont.) - Myofibrils run along muscle fibers - Have light and dark bands called striations - Being why skeletal muscle appears striated - Contractile units called sarcomeres form these bands as a result of their protein placement - When muscles are relaxed, a sarcomere extends between two dark lines called Z lines - Two types of protein filaments - Thick myosin - Thin actin The I band is light colored because it contains only actin filaments attached to a Z line. The dark regions of the A band contain overlapping actin and myosin filaments, and its H Zone has only myosin filaments
  • Slide 19
  • http://www.ucl.ac.uk/~sjjgsca/Muscleslidingfilament1.gif
  • Slide 20
  • http://www.ucl.ac.uk/~sjjgsca/MuscleSarcomere.gif
  • Slide 21
  • Macroscopic Physiology and Sliding Filament Model - Muscle contraction means that muscles have shortened - So, muscles can only pull and not push - Skeletal muscles must work in antagonistic pairs - For example, biceps contract to bend the arm in and triceps contract to straighten the arm out - One of the muscles in the pair must be relaxed to allow the other to shorten and result in pulling movement - When a sarcomere shortens, the actin filaments slide past the myosin filaments and approach one another. The causes the I band to shorten and the H zone to nearly or completely disappear. The movement of actin filaments in relation to myosin filaments is called the sliding filament model.
  • Slide 22
  • How do Muscles Get Their Energy? Myosin breaks down ATP o Makes bridges to pull actin toward sarcomere center ATP provides energy for contraction o Muscle fibers contain myoglobin (stores oxygen) cell respiration does not provide all needed ATP rely on phosphocreatine (storage) o anaerobically regenerates ATP with: creatine-P + ADP -> ATP + creatine Occurs during sliding filaments o most efficient way for muscles
  • Slide 23
  • How do Muscles Get Their Energy? (cont.) When all creatine-P is expended, fermentation produces ATP sans oxygen o builds lactate muscle ache and fatigue are the result We do deep breathing after exercise to metabolize lactate and restores cells o We must "pay back"/"fix" the oxygen debt o The lactate goes to the liver 20% broken down into CO2 and H2O ATP gained from this converts remaining lactate to glucose
  • Slide 24
  • So This Energy Process Means: Regular exercise o Increases mitochondria for ATP process Less fermentation reliance Less lactate produced, less oxygen debt o Reduced fatigue: increased fitness/endurance
  • Slide 25
  • Muscles can be Fast or Slow Muscles are Fast Twitch or Slow Twitch Slow Twitch Muscles (Type I) o More efficient with resperation Densely packed with capillaries o Thus they become fatigued much slower However they are considered weaker o They can effectively use fats and carbohydrates Aerobic
  • Slide 26
  • Muscles can be Fast or Slow Fast Twitch Muscles (Type II) o Less efficient with resperation o Has less cappilaries This explains its paler color o Stronger than slow twitch o Certain types are anaerobic, explaining why they tire quickly
  • Slide 27
  • Smooth Cardiac and Striated Muscles Respond Differently Skeletal muscles are voluntary o We can willingly control them o React through conscious impulses from the brain Smooth muscles are involuntary o Automatically controlled by our medulla oblongata o Found in stomachs and bladders Cardiac muscles are also involuntary o Controlled by medulla oblongata o Found only in the heart o Structured like that of a skeletal muscle It is striated
  • Slide 28
  • Look at Electron Micrographs Skeletal Muscles
  • Slide 29
  • Look at Electron Micrographs Smooth Muscles
  • Slide 30
  • Look at Electron Micrographs Cardiac Muscle
  • Slide 31
  • Tendons
  • Slide 32
  • Role of Tendons Connects muscles to bones o Works in union with muscles Without it, muscles would not h