Week 11 — Readings & Resources · The Muscular System

Course: Anatomy & Physiology I (BIOL 2301 + BIOL 2101) · Silver Oak University (fictional sample) · Prof. Navarro
Objective covered: Objective 5 — Skeletal-muscle organization (origin/insertion), muscle teamwork (agonist/antagonist/synergist), lever systems, and the major muscles and their actions.

How to use this page

Everything here is a link to an external resource — open it in your browser, the same way you'd open a YouTube link. Nothing needs to be downloaded.

This week's load is deliberately light: 1 video + 2 short readings + 1 interactive atlas, grouped by the ideas from the lecture. Watch or read one item per group and you're ready for the quiz; do all of them and you'll be very comfortable. Total time is roughly 35–45 minutes if you do everything, far less if you pick one per group.

Order that matches the lecture: ① origin/insertion & muscle teamwork → ② levers & the force-vs-speed tradeoff → ③ the major muscles & their actions.

A habit to start now: before you trust any A&P claim — in these resources, in a chatbot, or anywhere — ask the questions from class: Which attachment is the fixed origin and which is the moving insertion? Is this the agonist or the antagonist for the named movement? Does the muscle's position predict the action being claimed?

① Origin/Insertion & How Muscles Team Up

Maps to Lecture Segments 2–4. A muscle only pulls; its origin is the fixed bone and its insertion is the moving bone; movement is a team sport of agonist, antagonist, and synergist.

Video — "Muscles, Part 2: Organismal Level" (CrashCourse Anatomy & Physiology #22)
🔗 https://www.youtube.com/watch?v=I80Xx7pA9hQ
Why it earns the click: an energetic ~10-minute tour of exactly our week — how skeletal muscles push and pull, and how they work in functional groups (prime movers, antagonists, and synergists, ≈ 2:27), plus motor units and twitch summation as a bonus. Watch the first half closely; it previews the teamwork idea cold.
⏱ ~10 min

Reading — "Anatomy and Physiology 2e," §11.1 Interactions of Skeletal Muscles & Their Lever Systems (OpenStax)
🔗 https://openstax.org/books/anatomy-and-physiology-2e/pages/11-1-interactions-of-skeletal-muscles-their-fascicle-arrangement-and-their-lever-systems
Why it's assigned: the cleanest plain-language statement of origin vs. insertion, agonist / antagonist / synergist / fixator, and a table of real antagonist pairs (biceps/triceps, hamstrings/quadriceps) — a free online textbook page, no account needed. It also introduces the lever system for Group ②.
⏱ ~12 min

② Levers & the Force-vs-Speed Tradeoff

Maps to Lecture Segments 5–6. Bones are levers, joints are fulcrums, muscles supply the effort, and most body levers are third-class — fast but working at a force disadvantage.

Reading — "Anatomy and Physiology 2e," §11.1 — "The Lever System of Muscle and Bone Interactions" (OpenStax)
🔗 https://openstax.org/books/anatomy-and-physiology-2e/pages/11-1-interactions-of-skeletal-muscles-their-fascicle-arrangement-and-their-lever-systems
Why it's assigned: the section's final part lays out the lever, fulcrum, effort, and load using the hammer-and-nail analogy and maps each onto bone, joint, muscle, and weight — exactly the model behind this week's worked lever example (effort × effort-arm = load × load-arm). (Same page as Group ①; scroll to the lever section.)
⏱ ~6 min

③ The Major Muscles & Their Actions

Maps to Lecture Segment 7. Learn each muscle with its action — deltoid abducts the arm, quadriceps extends the knee, gastrocnemius plantarflexes, and so on.

Interactive — InnerBody "Interactive Guide to the Muscular System" (free, no download)
🔗 https://www.innerbody.com/image/musfov.html
Why it earns the click: a free, clickable 3D-illustration atlas of the muscular system, organized by region, with a written tour that covers origin/insertion, the agonist–antagonist–synergist roles, muscle naming, and skeletal muscles as third-class levers. You'll use it in Lab 11 to identify major muscles and name their actions; spend five minutes now rotating through the arm and leg muscles.
⏱ ~8 min (browse)

Reading — "Anatomy and Physiology 2e," §11.2 Naming Skeletal Muscles (OpenStax)
🔗 https://openstax.org/books/anatomy-and-physiology-2e/pages/11-2-naming-skeletal-muscles
Why it's assigned: the single best reference for muscle-naming logic — location, shape, size, action, number of origins, and fiber direction — so you can decode an unfamiliar muscle name into its location and action. Skim the table; it makes the names stop feeling random.
⏱ ~8 min

Optional one-stop references (free online)

• GetBodySmart — Muscular System tutorials. Clean, labeled, interactive diagrams of the skeletal muscles by region; handy when you want to drill muscle names and actions.
  🔗 https://www.getbodysmart.com/muscular-system/
• Khan Academy — Human Anatomy & Physiology. A free unit with short articles and videos covering the muscular system and how muscles produce movement. A good place to return to all term.
  🔗 https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology

Pick-one quick path (≈20 min total)

In a hurry? Do exactly these two and you'll be ready for the quiz:
1. Watch the first half of "Muscles, Part 2: Organismal Level" (origin/insertion + the agonist/antagonist/synergist teamwork).
2. Skim OpenStax §11.1 (origin vs. insertion, the muscle-team roles, and the lever system — the heart of the quiz).

Heads-up (links rot): these point to outside sites that occasionally move or rename pages. If a link ever fails, tell Prof. Navarro and use the OpenStax §11.1–11.2 or GetBodySmart references above in the meantime.