Muscular System Flashcards
Function of Muscles (3)
- power locomotion
- produce heat
- produce electricity
3 types of muscle classification:
- red vs. white
- tonic vs. twitch
- skeletal vs. cardiac vs. smooth
What is the difference between red vs white muscles?
metabolism
Describe red (dark) meat
- resistant to fatigue (endurance)
- high mitochondria
- highly vascularized
- lots of myoglobin
Describe myoglobin
- carries oxygen to muscle tissues
- has 1 protein subunit & is quaternary in structure
Describe white meat
- fatigues easily
- less mitochondria
- less vascularization
- less of myoglobin
Tonic fibers:
- slow contraction & low force (resist fatigue)
- common in reptiles and amphibians -
- rare in mammals
Twitch fibers:
- fast contraction & high force (fatigue easily)
- common in mammals
Location of tonic fibers in mammals
- eye muscles
- middle ear mucles
Types of twitch fibers (3)
- Type I - slow-twitch oxidative fiber
- Type IIa - fast-twitch oxidative
- Type IIb - fast-twitch glycolytic
How do the twitch fiber types differ?
myosin isoform
Oxidative vs. glycolytic :
oxidative can do phosphorylation & electron transport chain because they have mitochondria vs. glycolytic must use glycolysis since there are no mitochondria
Oxidation vs. reduction
oxidation is lost (lose electron) vs. reduction is gained (gain electron)
Glycolysis vs. krebs vs. ETC
Glycolysis - occurs in cytoplasm - 2 net ATP ( no O2 needed)
Krebs - occurs in mitochondria - 2 net ATP (needs O2)
ETC - occurs in mitochondria w/ NADH/FADH2 - 34 net ATP (needs O2)
What is carb loading?
build-up glycogen stores in liver & skeletal muscles for quick easy access to energy (prior to marathon etc.)
Type I
Slow-twitch oxidative fiber
1. does not stop at glycolysis
2. lots of mitochondria
3. endurance
4. reddish color
5. many capillaries
6. little glycogen
7. high myoglobin
Type IIb
Fast-twitch glycolytic
1. glycolysis only
2. power & quickness not endurance
3. few mitochondria
4. few capillaries
5. high glycogen
6. low myoglobin
Type IIa
Fast-twitch oxidative
1. hybrid of other 2 (not very common)
2. contract fast, resist fatigue
- ex. someone who trains for the Tour de France
Marathon training alters fiber composition. What changes would occur?
Increase in Type I (slow-twitch oxidative) and Increase in vascularization
What are the 3 types of muscle fibers?
- cardiac
- skeletal
- smooth
Skeletal muscle fiber features (5)
- locomotory muscles
- voluntary
- striated
- multinucleate
- many mitochondria
Cardiac muscle fiber features (10)
- short, branched fibers
- striated
- 1-2 nuclei per fiber/cell
- many mitochondria
- few neuromuscular joints
- fibers join at intercalated discs
- form thick myocardium
- involuntary
- hormonal & nervous control
- self-stimulation via sinoatrial node (SA node)
How do cardiac muscle fibers connect and communicate?
electrically linked by gap junctions
Locations of smooth muscle
- GI tract
- arrector pili
- iris of eye
intercalated disc (cardiac)
desmosome (cardiac)
intercalated disc (cardiac)
cardiac muscle (cardiac)
sarcolemma (cardiac)
nucleus (cardiac)
mitochondrion (cardiac)
gap junction
Smooth Muscle Features (8)
- short, almond (spindle) shaped
- single nucleus
- involuntary
- no striations
- myofilaments, but no sarcomeres
- myofilaments attach to dense bodies (equivalent to sarcomere)
- slow, sustained contraction
- controlled by hormones & nerves
What is the relative speed of smooth muscle contraction and relaxation compared to skeletal & cardiac muscle?
slow
What are the 2 contraction patterns of smooth muscle
- phasic contraction
- tonic contraction
Phasic contraction & example
relaxed/uncontracted is normal state (contract & then be done) - peristalsis in esophagus
Tonic contraction & example
contracted is normal state & occasionally relaxes - pyloric sphincter
What are the Fascia layers
- superficial fascia (hyodermis)
- deep fascia
- subserous fascia
Deep fascia function & structure
fx: wrap around muscles & keeps them separate from each other (slide no friction) - also separates muscles, nerves, and vessels
structure: dense, regular CT