Page 501 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Musculoskeletal, skin, and connective tissue ` anatomy and physiology Musculoskeletal, skin, and connective tissue ` anatomy and physiology section iii 457

Types of muscle fibers
Type I Type II
ContRaCtion VEloCity Slow Fast
FiBER ColoR Red White
pREdominant mEtaBolism Oxidative phosphorylation Ž sustained Anaerobic glycolysis
contraction
mitoChondRia, myogloBin  
typE oF tRaining Endurance training Weight/resistance training, sprinting
notEs Think “1 slow red ox”

Vascular smooth muscle contraction and relaxation
Acetylcholine,
Agonist bradykinin, etc
Endothelial cells
Receptor
Ca 2+
Ca 2+

NO synthase
L-arginine NO

L-type voltage Ca 2+ Smooth muscle cell NO di usion
gated Ca 2+
channel
Action
potential – ↑ Ca 2+ NO
– – ↑ Ca –calmodulin
Membrane complex Myosin GTP cGMP
depolarization
2+
+ actin
Myosin–light-chain Myosin–light-chain
kinase phosphatase
(MLCK) Myosin-P (MLCP)
+ actin
CONTRACTION RELAXATION

↑ Ca 2+ CONTRACTION Nitric oXide RELAXATION

FAS1_2019_11-Musculo.indd 457 11/7/19 5:23 PM