Muscles and Motility

(Topic B3.3 – AHL Only)

Essential Idea(s): The roles of the musculoskeletal system are movement, support and protection.

 Unit Length: 3 Lessons (AHL Only)

  Guiding Questions

◊ How do muscles contract and cause movement?

◊ What are the benefits to animals of having muscle tissue?

Materials:

Self-Teaching Slides (AHL)   Quizlet Vocab Set
  Notes Template

 

IB Statement(s) and Objective(s)

B3.3.1: Adaptations for movement as a universal feature of living organisms

  • State that movement can occur within a body or as locomotion from one place to another.
  • Compare movement in motile and sessile species.
  • List an example of a motile and a sessile species.​

 

B3.3.2: Sliding filament model of muscle contraction

  • Outline the relationship between muscle fibers, myofibrils and sarcomeres.
  • Annotate a diagram of the sarcomere, including the role of the Z line, titin, thin actin filaments, thick myosin filaments, light band and dark band.
  • Explain the sliding-filament mechanism of muscle contraction, including the role of actin, myosin heads, cross bridges, ATP, and the power stroke.​

 

B3.3.3: Role of the protein titin and antagonistic muscles in muscle relaxation

  • State that a muscle can only exert force when it contracts. 
  • State that lengthening of a muscle happens when it relaxes. 
  • Define antagonistic pairs in relation to muscle movement.
  • State an example of an antagonistic pair of muscles.
  • Outline the role of the titin protein in muscle stretching.  
  • Outline the mechanism by which the protein titin stores potential energy.​

 

B3.3.4: Structure and function of motor units in skeletal muscle

  • Annotate a diagram of a neuromuscular junction, including the function of the function of the motor neuron, acetylcholine, and muscle fiber. 
  • Outline the structure and function of a motor unit. ​

 

B3.3.5: Roles of skeletons as anchorage for muscles and as levers

  • Compare and contrast the structure and function of endoskeletons with exoskeletons.
  • Compare the function of muscles, joints and bones to that of a lever.​

 

B3.3.6: Movement at a synovial joint

  • Define synovial joint.
  • State the function of structures found in a synovial joint, including the bones, cartilage, synovial fluid, ligaments, muscles and tendons. 
  • Label a diagram of the human hip joint inclusive of:  femur, pelvis, joint capsule, synovial fluid, muscles, ligament and cartilage.

 

B3.3.7: Range of motion of a joint

  • Compare the articulation of hinge joints with that of a ball and socket joint.
  • Measure the range of motion of the human hip in terms of flexion, extension, rotation, abduction and adduction.

 

B3.3.8: Internal and external intercostal muscles as an example of antagonistic muscle action to facilitate internal body movements

  • State the location of the internal and external intercostal muscles. 
  • Describe the state of contraction of the internal and external intercostal muscles during inspiration and expiration.
  • Outline the mechanism by  potential energy is stored during contraction of antagonistic muscles. 

 

B3.3.9: Reasons for locomotion

  • List reasons animal locomotion, with one example of each.

 

B3.3.10: Adaptations for swimming in marine mammals

  • Outline the adaptations for streamlining, locomotion and ventilation of lungs in marine mammals

Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it /  Ӕ = The academy  / Ⓡ = Read it

Ӕ: Screencast – A 3D Tour of Muscle Tissue (💁)

Use this Sketchfab to screencast a recording of muscle tissue, explaining to us the structure of muscles from organ to myofibril. Make sure you highlight the relationship between muscle fibers, myofibrils, and movement.

 

Ӕ: The Academy: Muscle Contraction (💁)

Make a Khan-academy style video to explain the formation of cross bridges and the sliding filament model (go here for inspiration). Carefully explain the steps that start with a nerve impulse and end with a muscle contraction, covering the key details covered in 11.2 as you go. 

 

ⓦ/ⓟ: Know Your Pain (💁 [writeup] / 👫 [podcast – max: 2])

Athletes are well familiar with the phenomenon of muscle cramps – the involuntary contraction of a muscle; sometimes resulting in the muscle “seizing” in the contractile state. Read through this article (scroll down to “basic science”), and explain what is actually happening within a muscle fiber when we get those painful muscle cramps. 

 

ⓦ: Film Review – National Geographic Extraordinary Muscles (💁)

Watch this film that explores the human muscle system by following two humans with muscular disorders: one with dystonia and one with Spinal Muscle Atrophy. Write a response to the film, outlining the details of how muscles work, and how certain disorders can disrupt this process. You should aim to align as much content from 11.2 as you see presented in the video. 

 

ⓦ: “Inquiry 5”: Q&A on Muscles (💁/ 👭max 2)

Create a list of 5 inquiry questions related to muscle structure and function. If working solo, write out answers to your own questions; if working in pairs, record yourselves asking each other your 5 questions. Remember that good inquiry questions are conceptual / open-ended…such as: “What mechanisms in a muscle could cause muscular disorders?; NOT: “What is the function of the sarcoplasmic reticulum?” 

*Try to write questions that cover as many topics from 11.2 as possible!

 

Edge of Tech: Elon Musk Wants to Read Your Mind

If you haven’t heard of Neuralink, it is Elon Musk’s latest and very real project to create a computer chip that can be implanted and interact with the brain. Using what you have learned in this unit, watch the presentation of Neuralink, and inquire what engineering would be needed in order for the Neuralink to allow paralyzed patients to walk and move again. 

 

Extra Stuff: 

Muscle Structure Review – good for practice!

Teachers…send me more! Email me at sphillips.ep@alice-smith.edu.my if you have solid lesson plans for this unit.