Exam 1a Flashcards
(40 cards)
What are the functions of skeletal muscle?
Movement Stability Communication Control of body openings and passages Heat production (as much as 85% of body heat)
How is skeletal muscle closely interrelated to other body systems?
Carries out functions by
- Which bones and joints form the musculoskeletal system, by means of which body movement occur
- working w/ respiratory,digestive, and circulatory systems
- depending on the integumentary system for protection and elimination of heat produced by muscular contractions
- depending on nervous system for stimuli
How is skeletal muscle organized from smallest to largest units?
- Endomysium, sleeve that surrounds each fiber and connects it to adjacent fibers
- Perimysium, surrounds each fasciculi and divides the muscle into a series compartments
- Epimysium, connective tissue which surrounds the entire muscle and separates the muscle from surrounding tissue
What are the functions of the connective tissue investment of skeletal muscle?
- connect muscle to bone or other structure
- provide a route through which nerves and blood vessels reach muscle fibers
- provide a non-contractile frame work which allows the contraction of muscle fiber to be transmitted to bone
Sarcolemma
Cell membrane that surrounds the individual fibers
Hypertrophy
Increase in size of a muscle due to increase in size of each muscle fiber
Hyperplasia
describes an increase in size due to an increase in number muscle fibers
Type 1 fibers
- Endurance muscles
- associated with continuous metabolic activity (aerobic metabolism)
Type II fibers
- light
- quick, power muscles
- associated with anaerobic metabolism
Sarcoplasmic reticulum
An elaborate tubular network which functions and transports calcium ions to the myofibrils
Transverse tubules (t-systems)
Tubular invaginations of the sarcolemma which allow electrical impulses to enter the muscle fiber and make their way to the myofibrils
Myoglobin
Red protein pigment, gives muscle color, and store oxygen fibers need for its metabolism
Myofibrils
The contractile apparatus of the muscle fibers, formed by thick and thin filaments known as myofilaments
I bands
Light areas of myofibrils as seen under microscope
A bands
Dark areas as seen under microscope
H bands
Light areas in the middle of each dark band as seen under microscope
M bands
The thin dark line down the center of each H-band
Z lines
Thin dark line in the middle of each I band
The addition of ATP allows the system to operate by allowing
Myosin to interact with actin
ATP
Fuel of the muscle (energy is provided by breaking the adenosine-tri-phospate into adenosine-di-phosphate and a free phosphate ion), requires as much to contract as relax
Aerobic
- takes place in mitochondria
- most efficient producer of ATP
- excess ATP is released as heat
- prefers fatty acids as triglycerides to produce ATP
Anaerobic
- Depends on Creatine phosphate and glycogen to produce ATP
- creatine used first (always present in muscle)
- glycogen produces ATP through glycolysis (stored in muscle cells and liver) gets bogged down by lactic acid
- gets things going
Three phases of exercise
Phase 1 - used. To start the race (anaerobic-creatine)
Phase 2 - efficiency (aerobic-fatty acids)
Phase 3 - end of race (anaerobic-glycogen)
Glycogen carb/ carb loading
Only effects phase 3 of exercise, less effective in well trained athletes
- side effects; light headed, dizzy and lethargic, mental acuity may suffer, for every gram of glycogen stored approx 3 grams of water stored also ie extra weight
