Study Guide MT2

Study Guide MT2 - Midterm 2 Lecture 15 Muscle Physiology...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Midterm 2 Lecture 15 Muscle Physiology Muscle Comprises largest group of tissues in body o Produce force; different control mechanisms o Similar contractile mechanisms; different morphologies Three types of muscle o Skeletal muscle (40-50% of body mass) Make up muscular system- voluntary o Smooth muscle (5-10% of body mass) Appears throughout the body systems as components of hollow organs and tubes involuntary; ANS control o Cardiac muscle Found only in the heart; involuntary; ANS control Classified in two different ways o Striated or unstriated o Voluntary or involuntary Categorization of Muscle Striated muscle: skeletal and cardiac Unstriated muscle: smooth Voluntary muscle: skeletal Involuntary muscle: cardiac and smooth Muscle Controlled muscle contraction allows o Purposeful movement of the whole body or parts of the body o Manipulation of external objects by reaching out and such o Propulsion of contents through various hollow internal organs (small intestines) o Emptying of contents of certain organs to external environment (bladder) Muscle contraction A 1-2 second action potential can cause a muscle twitch of about 100 seconds Structure of Skeletal Muscle Muscle consists a number of muscle fibers lying parallel to one another and held together by connective tissue Single skeletal muscle cell is known as a muscle fiber o Multinucleated o Larger, elongated, and cylindrically shaped o Fibers usually extend entire length of muscle (from tendon to tendon) Myofibrils o Inside the cell body are myofibrils o Contractile elements of muscle fiber o Regular arrangement of thick and thin filaments Thick filaments myosin (protein) Thin filaments actin (protein) Sarcomere o Functional unit of skeletal muscle o Found between two Z lines (connects thin filaments of two adjoining sarcomeres) o Shortening the sarcomere produces force Muscle > muscle fiber bundles > each bundle contains several muscle cells > one muscle cell contains many myofibrils Each myofibril is composed of many segments of Dark A bands and Light I bands Myosin Component of thick filament Protein molecule consisting of two identical subunits shaped somewhat like a golf club o Tail ends are intertwined around each other o Globular heads project out at one end Tails oriented toward center of filament and globular heads protrude outward at regular intervals o Heads form cross bridges aka bonds between thick and thin filaments o Two important sites An actin-binding site: myosin binds to the actin A myosin ATPase (ATP-splitting) site: where the energy source derived for the force The myosin are laid out in an hexagonal order; the heads pointing towards the Z line Actin Primary structural component of thin filaments Spherical in shape Thin filament also has two other proteins o Tropomyosin and troponin Each actin molecule has special binding site for attachment with myosin cross bridge...
View Full Document

This note was uploaded on 11/02/2010 for the course GEL GEL 107 taught by Professor Jishin during the Winter '09 term at UC Davis.

Page1 / 27

Study Guide MT2 - Midterm 2 Lecture 15 Muscle Physiology...

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