Study Guide for Chapter 10 Quiz
Chapter 10 Muscle Tissue
What are the 3 types of muscle tissue? Skeletal muscle tissue: Attached to the skeleton; comprise the muscular system, and allow us to move. Cardiac muscle tissue: Only present in heart. Smooth muscle tissue: Involuntary; present in internal organs (they are not organs in themselves)
What are the 6 functions of skeletal muscle? Produce skeletal movement, Maintain posture and body position, Support soft tissues, Guard entrances and exits, Maintain body temperature, and Store nutrient reserves.
Define and be able to identify: Epimysium, Perimysium, and Endomysium: Epimysium: Exterior collagen layer; connected to deep fascia. Separates muscle from surrounding tissues. Perimysium: Surrounds muscle fiber bundles (fascicles).Contains blood vessel and nerve supply to fascicles. Endomysium: Surrounds individual muscle cells. Contains capillaries and nerve fibers contacting muscle cells. Contains my satellite (stem) cells that repair damage.
These tissues combine at the ends of muscles to form __tendons_____ or __________aponeurosis.____
Another name for a skeletal muscle cell is _______organ._______________
Describe a skeletal muscle cell in terms of: size, number of nuclei, cells from which it originates arrangement of myofibrils: Skeletal muscles are enormous. A muscle fiber from thigh muscle could have a diameter of 100um and a length up to 30 um which are 12 in. A second major difference is that the skeletal muscles fibers are multinucleate: each contains hundreds of nuclei just internal to the plasma membrane. Each nucleus in skeletal muscles fiber reflects the contribution of a single myoblast. The genes in these nuclei control the production of enzymes and the structural proteins required for normal muscle contraction.
The plasma membrane of a skeletal muscle cell is called the _____sarcolemma________ and it is continuous with the _______sacroplasm_____ that tunnel through the interior of the cell.
What is the sarcoplasmic reticulum and what is its function? A membranous structure surrounding each myofibril. Helps transmit action potential to myofibril. Similar in structure to smooth endoplasmic reticulum. Forms chambers (terminal cisternae) attached to T tubules.
What is a sarcomere and what is its function? The contractile units of muscle. Structural units of myofibrils. Form visible patterns within myofibrils. A striped or striated pattern within myofibrils Alternating dark, thick filaments (A bands) and light, thin filaments (I bands).
Be able to identify the different structures of the sarcomere on a diagram (thick/myosin filaments, thin/actin filament, Z line, M line, A band, I band, zone of overlap)
What ions are needed for muscle contraction to occur? What does the ion do? Calcium ions are needed for muscle contraction to occur. They trigger contraction. Requires myosin head to be in “cocked” position and loaded by ATP energy.
What is a cross-bridge and how is it formed? Once the active sites are exposed, the energizedmyosin heads bind to them, forming cross-bridges.
Be able to put the following events of the neuromuscular junction in order as they occur:
9. Power stroke
8. Formation of cross-bridges
5. Release of Ca2+ from SR
2. Release of acetylcholine from synaptic terminal
7. Exposing of active sites on actin
4. Depolarization of sarcolemma and T tubules
1. Action potential travels down axon of motor neuron
3.Acetylcholine binds to receptors on sarcolemma
6. Ca2+ binds to troponin
10. ATP causes cross-bridges to break
11. Myosin heads reactivated
What causes rigor mortis? When does rigor mortis begin and when does it end? Rigor Mortis: a fixed muscular contraction after death. Caused when: Ion pumps cease to function; ran out of ATP. Calcium builds up in the sarcoplasm.
What is wave summation? Wave summation: Increasing tension or summation of twitches. Repeated stimulations before the end of relaxation…