Week 11 — The Muscular System

Human Anatomy and Physiology I Free sample edition

Why this matters

A future physical therapist explaining which muscle lifts the forearm and a parent lifting a toddler from the floor both use this week's pulls and levers.

In plain language

Last week you looked inside one muscle fiber; this week you step back and watch whole muscles move your bones. Every muscle hangs between two bones, and when it contracts it pulls one bone toward the other. Muscles work in teams (groups of muscles that share one movement, each with its own role), and they work across your joints as levers (rigid bars that turn about a fixed point). You will learn to read a muscle's name as a set of clues, to work out how hard a muscle must pull, and to name ten major muscles by what they do. By the end, a curl, a stair climb, and a step onto your toes will each read as a short, ordered story about pulling.

Already covered: Week 9 named the joints and their movement pairs. Week 10 showed one fiber shortening as its filaments slide.
This week: origin and insertion, the muscle team, kinds of contraction, muscle names, levers, and ten major muscles.
How they connect: Week 10's fibers pull as whole muscles on Week 9's bones.
Where we're going next: Week 12 opens the neuron and its action potential.

Focus

Which end of a muscle moves, how do muscles team up, and why does a third-class lever trade force for speed?

By the end of this module, you should be able to:

[ ] name a muscle's origin and insertion and its team roles
[ ] sort a contraction as concentric, eccentric, or isometric
[ ] classify a lever and work the forearm lever with units
[ ] match ten major muscles to their actions

To-do

Plan your week

Read Chapter 11 (about 45 minutes), then the lecture and slides.
Work the tutorial (60–90 minutes) and practice set (20 minutes).
Do the A&P Lab & Inquiry (two hours), the discussion, and the assignment.
Take the quiz.

This week's checkpoint: name the biceps brachii's origin and insertion, then say why the forearm lever is fast, not strong.

You've got this

Ask your instructor early if you get stuck.

Built with The Course Maker · samples.thecoursemaker.com