47. Muscle Systems

Musculoskeletal System

Structure of a Myofibril

Muscle Contraction - Part 1

MUSCULAR SYSTEM ANATOMY:Muscle fiber with neuromuscular junction model description

2-Minute Neuroscience: Neuromuscular Junction

8.4.3 How Muscles Work - Sliding Filament Theory

Which of the following statements about skeletons is true?
a. Chitin is a major component of vertebrate skeletons.
b. Loss of forelimbs in snakes involved little change in the axial skeleton.
c. Most cnidarians must shed their skeleton periodically to grow.
d. Vertebrate bones contain living cells.

Motor Unit and Neuromuscular Junction

Neuromuscular Junction (NMJ) Structure and Action

Arm muscles and leg muscles are arranged in antagonistic pairs. How does this affect their functioning?
a. It provides a backup if one of the muscles is injured.
b. One muscle of the pair pushes while the other pulls.
c. A single motor neuron can control both of them.
d. It allows the muscles to produce opposing movements.

In terms of both numbers of species and numbers of individuals, insects are the most successful land animals. Write a paragraph explaining how their exoskeletons help them live on land. Are there any disadvantages to having an exoskeleton?

Skeleton & Joints

During the contraction of a vertebrate skeletal muscle fiber, calcium ions
a. break cross-bridges as a cofactor in hydrolysis of ATP.
b. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
c. transmit action potentials from the motor neuron to the muscle fiber.
d. spread action potentials through the T tubules.

BioFlix: From Muscle Cells to Movement

BioFlix: Sliding Filament Model

8.4.4 Slow Twitch v Fast Twitch Fibers

Having an internal skeleton would not allow the fine movements an earthworm uses when it moves.

No. A snake such as a sidewinder can move very gracefully over soft terrain, and it has an internal skeleton.

Having an internal skeleton would prevent an earthworm from being able to burrow underground tunnels.

Many vertebrates live underground. Some, like the mole, can dig very extensive networks of tunnels.

Having a hydrostatic skeleton means that having muscles is not a requirement for movement.

No. A hydrostatic skeleton is actually a fluid-filled cavity or compartment that responds to muscle contractions. Because fluids cannot be compressed, the earthworm will elongate when circular muscles in individual segments contract.

No. One of the listed responses is correct.

Having a hydrostatic skeleton allows the earthworm to use peristaltic motion to move over the substrate.

Consider how the two skeletons differ.

Why is having a hydrostatic skeleton rather than an internal skeleton advantageous to an earthworm?

The individual cells are joined by intercalated discs.

No. Intercalated discs are found only between the cells of cardiac muscle.

The basic contractile unit is the sarcomere.

No. Sarcomeres are found in striated muscle and not in smooth muscle.

They have transverse tubules along which the action potential travels before it stimulates the release of calcium from the endoplasmic reticulum.

No. There are no transverse tubules in smooth muscle.

The binding site for calcium is located on the troponin complex.

Calcium must enter the cytosol before contraction can occur.

Think about the structure and control of skeletal, cardiac, and smooth muscle.

What do all muscle tissues have in common?

Slow-Twitch vs Fast-Twitch: Which one is better for your body?

No. Skeletal muscle does not have intercalated disks.

No. Smooth muscle is not striated and does not have intercalated disks.

No. Skeletal muscle does not have intercalated disks. Smooth muscle is not striated and does not have intercalated disks.

Only one muscle type has intercalated disks.

What type of muscle is striated with intercalated disks?

The Sliding Filament Theory

BioFlix: Actin and myosin in muscle contraction

No. Flying animals use more energy than swimming with the same body mass.

No. Running animals generally expend more energy per meter traveled than equivalently sized animals specialized for swimming.

No. Both flying animals and running animals use more energy than swimming with the same body mass.

This form of locomotion uses little energy to resist gravity.

When comparing the different styles and adaptations of each major type of locomotion, what is the most energy-efficient mode of locomotion?

Describe how you bend your arm, starting with action potentials and ending with the contraction of a muscle. How does a strong contraction differ from a weak one?

BioFlix: Roles of Calcium and ATP

Endoskeleton

BioFlix: Muscle Structure

Which of the following is critical to the function of most exoskeletons, endoskeletons, and hydrostatic skeletons?
a. Muscles interact with the skeleton in antagonistic groups.
b. Muscles attach to each of these types of skeleton via tendons.
c. Muscles extend joints by pushing skeletal elements.
d. Segments of the body or limbs are extended when paired muscles relax in unison.

Neuromuscular junction

How did data on sarcomere structure inspire the sliding-filament model of muscle contraction? Explain why the observation that muscle cells contain many mitochondria and extensive smooth endoplasmic reticulum turned out to be logical once the molecular mechanism of muscular contraction was understood.

Neuromuscular Junction

In muscle cells, myosin molecules continue moving along actin molecules as long as
a. ATP is present and troponin is not bound to Ca2+.
b. ADP is present and tropomyosin is released from intracellular stores.
c. ADP is present and the intracellular acetylcholine level is high.
d. ATP is present and the intracellular Ca2+ concentration is high

Muscle System and Skeleton

MUSCLE FIBERS, MYOFIBRILS, SARCOMERES

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

Compare and contrast the structure and function of the three types of skeletal muscle fibers.

4_2 The Musculoskeletal System

Muscle A and muscle B have the same number of fibers, but muscle A is capable of more precise control than muscle B. Which of the following is likely to be true of muscle A? (Explain your answer.)
a. It is controlled by more neurons than muscle B.
b. It contains fewer motor units than muscle B.
c. It is controlled by fewer neurons than muscle B.
d. It has larger sarcomeres than muscle B.

MUSCULAR SYSTEM ANATOMY:Muscle fiber with sarcomere model description

Structure of a Sarcomere | Actin and Myosin | Myology | Nerve Muscle Physiology

Joints

No. This is true, but animals must also expend energy to overcome gravity.

No. Temperature is not a major factor affecting locomotion.

No. This is true, but animals must also expend energy to overcome friction.

No. Temperature and pressure are not major factors affecting locomotion.

What force(s) do you think an animal would need to overcome in order to move?

Locomotion requires that an animal expend energy to overcome __________.

Sliding Filament Theory | 5 Things You Need to Know + Pop Quiz

Rigor mortis is the stiffening of a body after death that occurs when myosin binds to actin but cannot unbind. What prevents myosin from unbinding?

slidingfilament#1

What is the role of calcium in muscle contraction?
a. Its binding to a regulatory protein causes the protein to move, exposing actin binding sites to the myosin heads.
b. It provides energy for contraction.
c. It blocks contraction when the muscle relaxes.
d. It forms the heads of the myosin molecules in the thick filaments inside a muscle fiber.

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

To discover the relationship between muscle-fiber types and performance, researchers obtained tiny biopsies of the gastrocnemius of 14 elite distance runners, 18 trained but non-elite distance runners, and 19 untrained subjects. They categorized the fiber types as slow or fast. (At the time of the study, intermediate fibers had not been identified as a third type.) Some of their data are shown here (* means). What conclusions can you draw from these data? <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/d8d84d3c188c1d31-1677308855107.jpg" style="width: 300px;">

Muscle 2- Skeletal muscle organs

The Sarcomere Contraction Bedtime Story

Classification of joints

Short Video: Tubeworms

GCSE PE - MUSCLE FIBRE TYPES - Anatomy and Physiology (Skeletal and Muscular System - 1.6)

An owl swoops down, seizes a mouse in its talons, and flies back to its perch. Explain how its wings enable it to overcome the downward pull of gravity as it flies upward.

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

Imagine that Paula Radcliffe is racing against a bird and a fish, each with the same mass as Paula. Which organism would have the highest cost of locomotion during the race?

Complete this concept map on animal movement. <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/7014fac53e2c1325-1677808762147.jpg" style="width: 300px;">

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

Predict who would likely have a greater proportion of fast glycolytic fibers in their gastrocnemius (calf) muscle—an elite distance runner or an elite sprinter. Explain.

Sliding Filament Model

The Skeletal System 2 - Types of Joint Movements

The Sliding Filament Theory of Muscle Contraction | FOUR STEPS

Musculoskeletal System Overview

Basics of Muscle Fiber Types

Neuromuscular Junction Video

Gravity would have the least effect on the movement of which of the following? (Explain your answer.)
a. a salmon
a. a snake
a. a sparrow
a. a grasshopper

Skeletal Muscle Tissue: Contraction, Sarcomere, Myofibril Anatomy Myology

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

The researchers looked more closely at the data within the group of elite runners. Although the mean proportion of slow fibers was 79 percent in this group, individual values ranged from 27 percent in one runner to 98 percent in another. How does this finding affect your interpretation of the relationship between athletic performance and muscle-fiber types?

6 Types of Joints found in the Human Body

Types of Joints - The structure of Skeleton and Bones

Animation: Terrestrial Biomes

Muscular System- The Neuromuscular Junction

Drugs are often used to relax muscles during surgery. Which of the following chemicals do you think would make a better muscle relaxant, and why? Chemical A: Blocks acetylcholine receptors on muscle cells. Chemical B: Floods the cytoplasm of muscle cells with calcium ions.

Chapter 9. Fast and Slow Twitch Muscle Fibers

Muscular System Skeletal Muscle Anatomy

Fast and Slow Twitch Muscles

The Musculoskeletal System | Biology

Muscle Fibers and Sarcomeres

sliding filament#2

Which of the following statements regarding control of muscle tissue is/are correct? Select True or False for each statement.
T/F All skeletal muscles are voluntary.
T/F Cardiac muscle is involuntary.
T/F Some smooth muscle tissues are voluntary and others are involuntary.
T/F Parasympathetic and sympathetic neurons innervate skeletal, cardiac, and smooth muscle tissues.

HHMI BioInteractive: Blockage of Motor Neuron Synapses

Distance runner Paula Radcliffe has won dozens of long-distance races and held the women’s world record for the marathon since 2003. Scientists, trainers, and athletes alike have wondered about the extent to which muscle structure and function contribute to success in athletes such as Radcliffe. What makes elite distance runners so good? Are their muscles somehow different from those of less successful athletes and non-athletes?

Predict the effect of training for a marathon on the number of muscle cells in the gastrocnemius. Explain.

A human’s internal organs are protected mainly by the
a. hydrostatic skeleton.
b. axial skeleton.
c. exoskeleton.
d. appendicular skeleton.

HHMI BioInteractive: Cone Snail Toxins

An earthworm’s body consists of a number of fluid-filled compartments, each with its own set of longitudinal and circular muscles. But in the roundworm, a single fluid-filled cavity occupies the body, and there are only longitudinal muscles that run its entire length. Predict how the movement of a roundworm would differ from the movement of an earthworm.

Animation: Digger Wasps and Landmarks

Muscle Fibre types Slow twitch and Fast twitch GCSE PE in 3 revision in 3 minutes

Parts of the Sarcomere

The greatest concentration of thoroughbred horse farms is in the bluegrass region of Kentucky. The grass in the limestone-based soil of this area is especially rich in calcium. How does this grass affect the development of championship horses?

Using examples, explain this statement: “Vertebrate skeletons are variations on a theme.”

GCSE PE - JOINT TYPES - Anatomy and Physiology (Skeletal and Muscular System - 1.2)

SCIENTIFIC THINKING Imagine you have a friend who had her child’s ACTN3 genotype tested. After reviewing the study described in Module 30.12, what cautions would you offer about interpreting the test results?

Which of the following bones in the human arm corresponds to the femur in the leg?
a. radius
b. tibia
c. humerus
d. metacarpal

Types of Synovial Joints

Thick filaments stretch, whereas thin filaments stay the same length.

No. Neither the thin filaments nor the thick filaments change in length when the sarcomere shortens.

Thin filaments stretch, whereas thick filaments stay the same length.

A typical muscle fiber at rest contains enough ATP for millions of contractions.

No. A typical muscle fiber at rest contains only enough ATP for a few contractions.

Iron and fats bound to actin play a critical role in muscle cell contraction and relaxation.

No. Calcium ions and proteins bound to actin play a critical role in muscle cell contraction and relaxation.

Neither thin nor thick filaments change in size, although the area of overlap between them increases.

The sliding filament model of muscle contraction involves thick and thin filaments sliding past each other.

Which statement about muscle contraction is correct?

Fast Twitch VS Slow Twitch Muscle Fiber Types |physiotherapy |muscle physiology |physiotrendz

When a dog is running fast, its body position is stabilized by
a. side-to-side undulation.
b. energy stored in tendons.
c. foot contact with the ground.
d. its momentum.

When a person dies, muscles become rigid and fixed in position—a condition known as rigor. Rigor mortis occurs because muscle cells are no longer supplied with ATP (when breathing stops, ATP synthesis ceases). Calcium also flows freely into dying cells. The rigor eventually disappears because the biological molecules break down. Explain, in terms of the mechanism of contraction described in Modules 30.9 and 30.10, why the presence of calcium and the lack of ATP would cause muscles to become rigid, rather than limp, soon after death.

The Musculoskeletal System

Which of the following animals is correctly matched with its type of skeleton?
a. fly—endoskeleton
b. earthworm—exoskeleton
c. lobster—exoskeleton
d. bee—hydrostatic skeleton

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