Textbook Notes (368,434)
United States (206,040)
Boston College (1,174)
English (38)
ENGL 1010 (7)
Chapter

muscles study guide.doc

3 Pages
69 Views
Unlock Document

Department
English
Course
ENGL 1010
Professor
Laura Sterrett
Semester
Spring

Description
• Muscle fibers- only in skeletal/smooth muscles • Excitability- ability to receive and respond to a stimulus • Elasticity- ability to recoil and resume length after stretch • Excitability, elasticity, contractility, extensibility • Skeletal muscle is 40% of body mass • Fascicles- groups of endomysium-wrapped muscle fibers • Perimysium- fibrous connective tissue surrounding each fascicle • Epimysium- connective outer layer of muscle • Indirect attachments- tissue wrappings extend as tendons/aponeurosis • Myoglobin- red pigment storing oxygen in sarcoplasm • Myofibril- contractile elements of muscle cells • Sarcomere- region between two Z discs, smallest contractile unit • Endomysium, perimysium, epimysium • Troponin- TnI binds to actin to inhibit contraction, TnT positions tropomyosin on actin, TnC binds calcium atoms • SR stores and releases calcium when stimulated • Sliding filament theory- thin and thick filaments slide past one another to contract • Motor end plate- high surface area due to folding, location of Ach receptors • Acetylcholinesterase- breaks Ach into acetyl acid and choline, stops stimulation • Excitation-contraction coupling (EC)- action potential makes myofilaments slide • Calcium is removed by active transport after action potential ends • Wave summation- two identical stimuli delivered at high frequency builds response • Recruitment- motor unit summation • ATP regenerated by ADP and creatine phosphate interaction, anaerobic glycolysis of stored glycogen, or aerobic respiration • Anaerobic glycolysis- produces lactic acid • Slow red oxidative fiber- contracts slowly, oxygen dependent, high mitochondria, fatigue resistant • Fast glycolytic fiber- anaerobic glycolysis, white, tires quickly, contracts quickly, depends on glycogen • Fast oxidative fiber- intermediate, contract quickly, oxygen dependent • Calmodulin- calcium-binding protein in smooth muscle • Stress-relaxation response- muscle adapts to new contracted length and relaxes so it can retain ability to contract in smooth muscle (stomach shrinking & growing) • Preload- stretch on cardiac muscles right before contracting • Increased contractility= more blood ejected from heart = lower ESV • Afterload- pressure ventricles overcome to eject blood • Atrial reflex- increased venous return stretches atrial walls, HR up • Thyroxine- increase body heat and metabolic rate, causes sustained HR increase • tachycardia- abnormally fast heart rate due tu stressors • Bradycardia- slow heart rate • Congestive heart failure- CO too low to meet needs of tissues • Pulmonary congestion- left side of heart fails, suffocate from pulmonary edema • Peripheral congestion- right side of heart fails, blood stagnates in body organs and can’t get rid of waste/ give nutrients • Excitation-contraction coupling- action potential propagated down T tubules • Troponin binds to calcium to move tropomyosin out of the way • Myosin ATPases split ATP for detachment • Tetanus- smooth and sustained muscle contraction resulting from high frequency stimulation • Isometric- nothing moves despite contraction • Isotonic- muscle shortens/lengthens and load moves • Force of contraction affected by number/size of contracting cells, frequency of stimulation, and degree of muscle stretch • Three types of muscle fibers 1. Fast glycolytic (fatigable), 2. Slow oxidative (fatigue-resistant) 3. Intermediate fast oxidative (fatigue-resistant) • Smooth fibers- unstriated, spindle shaped, uninucleate, arranged in sheets, lack elaborate connective tissue coverings, no sarcomeres, no T tubules, underdeveloped SR, pace of contraction maybe set by pacemaker cells, can be electrically coupled by gap junctions, contracts slowly without fatigue • Calcium binds t
More Less

Related notes for ENGL 1010

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit