The Human Body: Concepts of Anatomy and Physiology (Third Edition)

Chapter 7— The Muscular System

The Human Body: Concepts of Anatomy and Physiology (Third Edition)

Lesson Plans

Chapter 7 — The Muscular System

Goals of the Lesson:

Cognitive: Students will be able to list the primary functions of the muscular system. They will be able to describe the connective tissues and microscopic components of skeletal muscle tissue. Students will be able to identify the parts of the neuromuscular junction. They will be able to explain the sliding filament mechanism of muscle contraction and describe the steps of muscle contraction. Students will be able to describe concepts related to energy sources for muscle contraction, oxygen debt, muscle fatigue, threshold stimulus, and all-or-none response. They will be able to explain twitch, tetanic, isotonic, and isometric contractions. Students will be able to define origin and insertion and describe the role of group actions in producing movement. They will be able to identify the primary muscles on the basis of their locations, origins, insertions, and actions.

Motor: N/A

Affective: N/A

Learning Objectives:

The lesson plan for each objective starts on the page shown below.

7-1Indicate the primary functions of muscles...... 3

7-2Describe the connective tissues associated with muscle...... 4

7-3Identify and describe the microscopic components of skeletal muscle tissue...... 5

7-4Identify the parts of the neuromuscular junction...... 7

7-5Explain the sliding filament mechanism of muscle contraction...... 9

7-6Describe in their proper order of occurrence the events leading to muscle contraction...... 10

7-7Indicate the roles of ATP in muscle contraction and how this energy is supplied...... 13

7-8Describe the oxygen debt and muscle fatigue...... 14

7-9Define threshold stimulus, and relate it to the concept of the all-or-none response...... 17

7-10Compare twitch, tetanic, isotonic, and isometric contractions...... 18

7-11Define origin and insertion, and describe the role of group actions in producing movement...... 20

7-12Identify the primary muscles on the basis of their locations, origins, insertions, and actions...... 21

You Will Need:

Gather the following materials and teaching aids for the following lessons:

7-2Unlabeled copies of Figure7-1 for each student

7-4Unlabeled copies of Figures7-5 and 7-6 for each student

7-6Computer and digital projector

Legend: PPt: PowerPoint

Objective 7-1

Indicate the primary functions of muscles.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
The Big Picture
600 muscles in body
40%-50% of body weight
Composed mainly of skeletal muscle tissue
Specialized to contract
Primary functions of the muscular system
  • Movement
  • Support
  • Heat production
  • Byproduct of movement
/ 155–156 / 1–5 / Figures
N/A
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
Have students fill in the notetaking section, if not completed before or during class, for the introduction on p. 134 of the Student Notebook.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-2

Describe the connective tissues associated with muscle.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Connective tissues of muscle
Fascia
  • Superficial
  • Deep
  • Epimysium (outer)
  • Perimysium (middle)
  • Endomysium (inner)
  • Tendon
  • Connects muscle to bone
  • Forms
Single band
Aponeurosis (broad sheet)
  • Loose connective tissue
  • Adipose tissue
/ 156–157 / 6–9 / Figures
7-1: Muscle structure
p. 157, PPt 7
7-2: Tendon repair surgery
p. 158, PPt 9
Boxes
Health Clinic: Tendon Injuries
p. 158
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
Have students pair off. Hand out unlabeled copies of Figure 7-1. Ask the students in each pair to quiz each other on the identity of the structures shown in this figure and to work together to label the parts. When the students have completed this, show the PowerPoint slide (7) containing this figure and identify the structures and their parts.
Materials
Unlabeled copies of Figure7-1 for each student / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-3.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-3

Identify and describe the microscopic components of skeletal muscle tissue.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Microscopic Structure of Muscle
Muscle cell (muscle fiber)
  • Long, cylindrical
  • Multi-nucleate
  • Sarcolemma: cell membrane of a muscle cell
  • Sarcoplasm: cytoplasm of a muscle cell
  • Mitochondria
  • Sarcoplasmic reticulum: membranous sac similar to endoplasmic reticulum
  • Stores calcium
  • Transverse tubules
  • Form channels between sarcoplasm & sarcoplasmic reticulum
  • Enable ions to flow
  • Myofibrils: cylindrical cords of protein that make up muscle fiber
  • Thick filaments (myosin; cross bridges)
  • Thin filaments (actin, troponin, & tropomyosin)
  • A band (dark)
  • H zone
  • I band (light)
  • Z lines
  • Sarcomere
/ 157–159 / 10–14 / Figures
7-3: The filaments of the myofibril
p. 159, PPt 11
7-4: The sarcomere
p. 160, PPt 14
Boxes
Health Clinic: Muscle Hypertrophy and Disuse Atrophy
p. 161
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
Have students write responses to the Concept Check questions for this section.
Have students fill in the notetaking section, if not completed before or during class, and complete the Review Time section for Concept 1: Muscle Structure on pp. 135–139 of the Student Notebook.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-4

Identify the parts of the neuromuscular junction.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Nerve Supply
Motor neuron: a nerve cell that transmits nerve impulses to stimulate muscle contraction
Synaptic knobs: enlarged distal ends of motor neuron that form junction with muscle fiber
Motor unit: functional unit of a single motor neuron, its terminal branches, & all muscle fibers it stimulates
Motor end plate:area of sarcolemma near where motor neuron & each muscle fiber communicate
Synaptic cleft: a small fluid-filled gap between the synaptic knob of a motor neuron & muscle fiber
Neuromuscular junction:the site of communication between motor neuron & muscle fiber, including synaptic knob, motor end plate, & synaptic cleft
Synaptic vesicles: tiny sacs in cytoplasm of motor neuron at terminal end that contain transmitter Ach
Neurotransmitter: a chemical that transmits information from 1 neuron to another or to a muscle
Steps of transmission
  • Nerve impulse arrives at terminal end of motor neuron & stimulates release of ACh
  • ACh diffuses across synaptic cleft & binds with receptors in motor end plate of muscle fiber
  • Binding triggers contraction sequence of muscle fiber
/ 159–161 / 15–18 / Figures
7-5: The motor unit
p. 160, PPt 16
7-6: The neuromuscular junction
p. 161, PPt 18
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
Have students pair off. Hand out unlabeled copies of Figures 7-5 and 7-6. Ask the students in each pair to quiz each other on the identity of the structures shown in these figures and to work together to label the parts. When the students have completed this, show the PowerPoint slides (16 & 18) containing these figures and identify the structures and their parts.
Materials
Unlabeled copies of Figures7-5 and 7-6 for each student / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-8.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-5

Explain the sliding filament mechanism of muscle contraction.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Physiology of Muscle Contraction
Sliding filament mechanism
  • Explains how an individual muscle fiber contracts
  • Thin filaments slide inward toward H zones
  • Each sarcomere along length of myofibril shortens
  • All myofibrils shortening simultaneously causes muscle fiber to shorten
  • Muscle contracts
/ 162 / 19 / Figures
N/A
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-8.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-6

Describe in their proper order of occurrence the events leading to muscle contraction.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Events Leading to Muscle Contraction
Muscle fiber at rest
  • Calcium ions stored in sarcoplasmic reticulum (SR)
  • ATP bound to thick filaments
  • Thin filaments intact & all 3 proteins are bound tightly
  • Fiber is ready to contract
Role of stimulus
  • ACh released into synaptic cleft
  • ACh binds to receptors on motor end plate
  • Impulse is generated & travels:
  • Along sarcolemma
  • Down T tubule membranes
  • Through SR
  • SR membrane becomes permeable to calcium ions
  • Calcium ions released into sarcoplasm & diffuse to myofibrils
Muscle contraction
  • Calcium ions bind to troponin molecules in thin filaments
  • Actin & troponin molecules change shape
  • Actin binding sites are exposed
  • Myosin heads bind to actin sites, coupling
  • Calcium ions activate breakdown of ATP
  • Energy is released & pivots myosin head (power stroke)
  • Thin filament shifts toward center of sarcomere
  • Myosin head breaks initial bond with actin site & forms new one closer to center of sarcomere
  • Cycle of coupling between thin & thick filaments, power stroke, & attachment repeats
  • Sarcomere shortens
  • Myofibril shortens
  • Muscle fiber contracts
Rigor mortis: sustained muscle contraction of body after death
Return to rest
  • Nerve impulse stops
  • ACh release stops
  • Remaining ACh is inactivated by enzyme
  • Calcium ions return to SR by enzymes via active transport
  • Thin filaments resume original shape
  • Actin sites are covered
  • Thin filaments slide back to original position
  • Muscle fiber relaxes
/ 162–164 / 19–24 / Figures
7-7: The sliding filament mechanism of contraction
p. 163, PPt 24
Boxes
N/A
Tables
N/A / Resources
Animation on companion website: Muscle Contraction
Related Chapters
N/A
In-Class Activities
Show the animation, Muscle Contraction, to the class, using a computer and digital projector.
Materials
Computer and digital projector / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-8.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-7

Indicate the roles of ATP in muscle contraction and how this energy is supplied.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Energy for Contraction
3 Most direct uses of energy
  • Power stroke
  • Detachment of myosin heads from thin filaments
  • Enzymatic return of calcium ions to SR
ATP
  • Immediate source of energy in the body
  • Stored in muscle fiber at rest
  • Used up in seconds
Creatine phosphate
  • Can be broken down to quickly regenerate ATP
  • Can fuel contraction for up to 15 seconds
Other sources that regenerate ATP, in order of use
  • Glucose
  • Glycogen
  • Lipids
/ 164 / 25–26 / Figures
N/A
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-8.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-8

Describe the oxygen debt and muscle fatigue.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Metabolism and Fitness
Metabolism: management of energy by cell
Catabolism: breakdown of molecules to release energy
  • Cellular respiration: breakdown of glucose by enzymes in mitochondria
  • Aerobic respiration
  • Use of oxygen during cellular respiration
  • First means of providing energy
  • Anaerobic respiration
  • Cellular respiration without oxygen
  • Used when oxygen is depleted
  • Less efficient
  • Produces lactic acid
Anabolism: creation of new molecules using energy
Myoglobin
  • A protein in muscle tissue that binds to oxygen & stores it until needed
Oxygen debt
  • The additional oxygen needed to restore all systems to normal states
High level of fitness
  • Reduces rate of lactic acid production
  • Increases storage capacity of oxygen
  • Delays metabolic switch to anaerobic respiration
Muscle fatigue: inability of a muscle to contract normally
Cramp: spasmodic contraction of a muscle without relaxing
Comparing Muscle Tissues
Skeletal muscle tissue
  • Attached to skeleton
  • Voluntary control
  • Long, cylindrical fibers
  • Striated
  • Most rapid contraction
  • Strongest contraction
  • Most rapid onset of fatigue
Smooth muscle tissue
  • In walls of hollow organs
  • Involuntary control
  • Spindle-shaped fibers
  • No striations
  • Slowest contraction
  • Weakest contraction
  • Intermediate speed of onset of fatigue
Cardiac muscle tissue
  • In wall of heart
  • Involuntary contraction
  • Rectangular, branching fibers
  • Striated
  • Intermediate speed of contraction
  • Intermediate strength of contraction
  • Least rapid onset of fatigue
/ 164–166 / 27–31 / Figures
N/A
Boxes
Health Clinic: The Effect of Exercise on Muscle
p. 165
Tables
7-1: Comparison of Muscle Tissues
p. 166, PPt 31 / Resources
N/A
Related Chapters
N/A
In-Class Activities
Have students pair off and quiz each other on their knowledge of the three types of muscle tissue, using Table 7-1 as a reference.
Materials
N/A / Outside Assignments
Have students write responses to the Concept Check questions for this section.
Have students fill in the notetaking section, if not completed before or during class, and complete the Review Time section for Concept 2: Physiology of Muscle Contraction on pp. 140–145 of the Student Notebook.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-9

Define threshold stimulus, and relate it to the concept of the all-or-none response.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Muscle Mechanics
All-or-none response
  • A muscle fiber either contracts all the way or not at all
  • Threshold stimulus: weakest stimulus that can initiate a contraction
  • All muscle fibers innervated by one motor neuron contract simultaneously when stimulus threshold is reached
  • Only as many motor units are recruited as needed to meet the force required
  • Recruitment: adding of motor units as stimulus strength increases
  • Thus, we can vary the strength of muscle contractions
  • The greater the # of motor units stimulated, the greater the strength of contractions
/ 167 / 32 / Figures
N/A
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
The Concept Check questions and Student Notebook exercises that cover this section are assigned in Objective 7-10.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-10

Compare twitch, tetanic, isotonic, and isometric contractions.Date:

Lecture Outline

/

Figures, Tables, and Features

/

Resources and

In-Class Activities

/

Outside Assignments

Evaluation

/

Instructor’s Notes

Content / Text page / PPt slide
Measuring Muscle Contraction
Twitch contraction
  • A rapid response to a single stimulus that is slightly over threshold
  • Lasts 1/10th of a second before muscle fiber returns to rest
Myogram: a graph that measures a contraction
  • Latent period: time delay of contraction after stimulus is applied
  • Period of contraction: phase in which muscle fiber increases in tension as sarcomeres shorten
  • Period of relaxation: muscle fiber returns to original length
Sustained Muscle Contraction
Summation
  • Combining of twitches due to shortened time interval between stimuli
  • Increases total force of contraction
Tetanic contraction
  • A contraction of maximal force
Complete tetanus
  • A fusion of twitches resulting from many stimuli
  • Provides a forceful, sustained contraction
  • Provides usual means of body movement
  • Provides muscle tone (a series of sustained contractions by a small # of fibers)
Isotonic and Isometric Contractions
Tension: the force exerted by a muscle contraction
Isotonic contraction
  • Produces movement
Isometric contraction
  • Produces tension but no movement
  • Muscle does not shorten
/ 167–168 / 33–37 / Figures
7-8: A myogram
p. 167, PPt 34
7-9: Types of muscle contractions
p. 168, PPt 36
Boxes
N/A
Tables
N/A / Resources
N/A
Related Chapters
N/A
In-Class Activities
N/A
Materials
N/A / Outside Assignments
Have students write responses to the Concept Check questions for this section.
Have students fill in the notetaking section, if not completed before or during class, and complete the Review Time section for Concept 3: Muscle Mechanics on pp. 146–149 of the Student Notebook.
Have students complete one or two of the student activities associated with Chapter 7 on the companion website.
Evaluation
N/A

Legend: PPt: PowerPoint

Objective 7-11

Define origin and insertion, and describe the role of group actions in producing movement. Date: