Biology Homework Chapter 30: Motion and Support
Textbook assignment: Chapter 30: How Animals Move, all sections.
- 30.1: Locomotion involves moving body sections to accomplish movement through the organism's environment. Specialized structures for animals in different environments support swimming, walking and running, hopping, crawling, and flying so that animals can change location to hunt, rest, eat, or reproduce.
- 30.2: Skeletons not only provide support and movement, they also provide protection. Hydrostatic skeletons provide support and motion while retaining maximum flexibility. Exoskeletons of chitin protect the soft body parts of invertebrates. Endoskeletons use skulls, vertebrae, and ribcages to protect soft body parts and nerve tissues.
- 30.3: The human body has 30 or so major bone types (some copied from one side of the body to the other, and many smaller bones in the hands and feet, organized to support weight for different kinds of movement. Homeotic genes control the development of limbs based on vertebrate structure.
- 30.4: Bones are made of cartilage, a thin, flexible coating at the joints, compact bone shells on the shaft providing structure, and spongy bone at the ends providing some flexibility in joint movement. Compact bones have a cavity filled with yellow marrow; spongy bones contain red marrow. Bones are living tissue that must be supplied with nutrients, so they are interlaced with blood vessels.
- 30.5: Healthy bones are somewhat flexible, and can respond to stress and heal from injuries. In older humans, diminished levels of activity reduce blood supplies to the bones or loss of calcium through low rates of absorption can cause brittleness, increasing the risk of fractures.
- 30.6: Three main types of joints allow rotation (pivot joint, such as the elbow), back-and-forth movement (hinge joint, such as the knee) and both types (ball-and-socket joint, such as the hip or shoulder). Other types of joints may combine different movements as well.
- 30.7: Muscles work in antagonistic pairs to move bones in different directions. Contracting the biceps and relaxing your triceps allows you to pull your lower arm so that your hand can touch your shoulder; relaxing the biceps and contracting the triceps allows you to extend your lower arm out to pick up something far from your body. Note that muscles do not stretch themselves beyond their "rest" length; an antagonistic muscle is required to stretch the resting muscle.
- 30.8: The components of muscles are bundles of linear components grouped together to form larger and larger strands: bundles of filaments of myosin and actin form → sarcomeres → myofibrils → cells (fibers) → muscles.
- 30.9: To move a muscle, ATP grabs an actin section on a myosin filament, and shift it in one direction. Like an extension rod in an umbrella, the muscle lengthens or contracts.
- 30.10: Muscles lengthen or contract in response to action potentials from motor neuron axons.
- 30.11: The ATP required for muscle movement comes from aerobic (oxygen-required) respiration (see chapter 6). Aerobic exercise increases the rate of aerobic respiration, while strength training exercises increase the flexibility and strength of muscles. Both forms of exercise are necessary to maintain body health and avoid injury.
- 30.12: Fast-twitch muscle fibers are able to move quickly in response to neural signals, but tire easily. Slow twitch fibers sustain repeated actions, but they are not as strong as fast-twitch fibers. Any given muscle has a combination of both types of fibers, which allows it to respond quickly and strongly in a "fight or flight" situation, then maintain longterm activity. The type of fiber response depends on the form of myosin in the fiber, and the rate at which the particular type of myosin can hydrolyze ATP.
Read the following weblecture before chat: Animal Movement (Skeletal and Muscular Systems)
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
- Required: Complete the Mastery Exercise with a score of 85% or better.
- Optional: Test yourself with the textbook multiple choice questions and note any that you miss that still don't make sense. Bring questions to chat!
- Go to the Moodle and take the quiz for this chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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