20081006

20081006 - PNB 250 Page #1 Lecture15 Smooth Muscle Review...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
PNB 250 Page # 1 Lecture15 Smooth Muscle *actin-myosin crossbridge activity same as skeletal muscle Review *cells lack striations and innervated by autonomic n.s. *precursor cells remain single cells – single nucleus *size, 2-10 μ m (much smaller than skeletal muscle fibers) t-tubules not necessary Myofilaments in smooth muscle 1. actin 2. myosin anchored to plasma membrane by “dense bodies” α -actinin (same as z-line) 3. cytoskeletal filaments (elastic framework) a. myosin 1/3 that of skeletal muscle b. actin 2X that of skeletal muscle c. 2 actins to 1 myosin in skeletal muscle d. 10-15 actins to 1 myosin in smooth muscle Result: more chaotic overlap actins are oriented toward long axis of cell no sarcomere structure mysin crossbridges all go in same direction in SM Length-tension relation differs tension length skeletal muscle smooth muscle
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
PNB 250 Page # 2 Smooth and skeletal muscle develop the same amount of tension per unit cross-sectional area – but smooth muscle can maintain tension over a greater length. This is due to the a. chaotic overlap of actin and myosin
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

20081006 - PNB 250 Page #1 Lecture15 Smooth Muscle Review...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online