chapter

Structure and and Respiratory
Muscular, Neuromuscular,
Cardiovascular,Function of the
Systems

1
Structure and Fu...
Chapter Objectives
• Describe the macrostructure and microstructure of muscle.
• Describe the sliding-filament theory.
• D...
The Muscular System
• ....DesktopESS 2600 VideosHuman Body
Pushing The Limits E1 part 2.mp4
Muscular System
• Macrostructure and Microstructure
– Each skeletal muscle is an organ that contains
muscle tissue, connec...
Muscle Belly
Epimysium (deep facia)

Fasciculus
Endomysium

Sarcolemma
Sarcoplasm
Myofilaments Myofibril
(actin &
myosin

...
Epimysium
• The epimysium encases the muscle
• All of the various layers of CT
(endomysium, perimysium and the
epimysium b...
Fasiculi
• Each fasiculi may consist of up to 150
fibers.
• Each muscle fiber is surrounded by a
connective tissue known a...
Muscle Belly
Epimysium (deep facia)

Fasciculus
Endomysium

Sarcolemma
Sarcoplasm
Myofilaments Myofibril
(actin &
myosin

...
Muscle Fibers
• Muscle fibers (also known as cells) are
about the same diameter as a strand of
human hair and can reach le...
Muscle
Fiber
Mitochondrion

Opening to
T-tubule

Sarcoplasm

T-tubule
Myofibril

Sarcolemma

Sarcoplasmic
reticulum
Muscle Contraction
• What is the smallest “contractile unit” of
skeletal muscle?
– The sarcomere

• Sarcomeres are lined u...
Figure 1.4
Muscular System
• What is the Sliding-Filament Theory of
Muscular Contraction?
– The sliding-filament theory states that t...
Figure 1.5
(Review) Nervous system
activation of a muscle
Tropomyosin
AP
Contraction of a Myofibril

– (a) In stretched muscle the I-bands and H-zone are
elongated, and there is low force potenti...
Neuromuscular System
Motor Unit
• The nervous system works via electrical
impulses (action potentials), it signals the
mus...
Figure 1.2
The Nervous System is Creepy
Key Point
• The discharge of an action potential from a
motor nerve signals the release of calcium
from the sarcoplasmic r...
Section Outline
• Neuromuscular System
–
–
–
–
–

Activation of Muscles
Muscle Fiber Types
Motor Unit Recruitment Patterns...
Neuromuscular System
•
•

Activation of Muscles
What chemical is released following an action potential?
– Arrival of the ...
Neuromuscular System
ACTIVATION OF MUSCLES
(neuromuscular junction)
Once enough acetylcholine
crosses the neuromuscular
junction, the action po...
All-or-none principle
• All of the muscle fibers in the motor unit
contract and develop force at the same time.
There is n...
Stimulated Motor Unit
• Twitch, twitch
summation, and
tetanus of a motor
unit:
– a = single twitch
– b = force resulting
f...
Neuromuscular System
• Muscle Fiber Types
– Type I (slow-twitch)
– Type IIa (fast-twitch)
• Type IIab (fast-twitch); now n...
Table 1.1
MUSCLE FIBER TYPES
• Postural muscles
are typically
composed of a
higher percentage
of type 1 fibers
• Whereas larger
musc...
Key Point
• Motor units are composed of muscle fibers
with specific morphological and physiological characteristics that d...
Neuromuscular System
• Motor Unit Recruitment Patterns During
Exercise
– The force output of a muscle can be varied throug...
Table 1.2
Neuromuscular System
• Preloading
– Occurs when a load is lifted,
since sufficient force must be
developed to overcome the...
Neuromuscular System
• How Can Athletes Improve Force
Production?
– Recruit large muscles or muscle groups during an
activ...
Key Point
• Proprioceptors are specialized sensory
receptors that provide the central nervous
system with information need...
Neuromuscular System
• Proprioception
– Muscle Spindles
• Also known as intrafusal fibers
• Muscle spindles are propriocep...
Muscle Spindle
• Figure 1.7
– When a muscle is stretched, deformation of the
muscle spindle activates the sensory neuron, ...
Figure 1.7
Neuromuscular System
• Proprioception
– Golgi Tendon Organs (GTO)
– Where are GTOs located?
• Golgi tendon organs are prop...
Golgi Tendon Organ
• What happens when you lift something that
is far too heavy?
– When an extremely heavy load is placed ...
Figure 1.8
Neuromuscular System
• Older Muscle
– Muscle function is reduced in older adults.
– Reductions in muscle size and strength...
Section Outline
• Cardiovascular System
– Heart
• Valves
• Conduction System
• Electrocardiogram

– Blood Vessels
• Arteri...
Cardiovascular System
• Heart
– The heart is a muscular organ made up of two
interconnected but separate pumps.
• The righ...
Heart and Blood Flow
• Figure 1.9 (next slide)
– Structure of the human heart and course of blood
flow through its chamber...
Figure 1.9
Cardiovascular System
• Heart
– Valves
• Tricuspid valve and mitral (bicuspid) valve
• Aortic valve and pulmonary valve
• ...
Electrical Conduction System
• Figure 1.10 (next slide)
– The electrical conduction system of the heart
Figure 1.10
Cardiac Impulse
• Figure 1.11 (next slide)
– Transmission of the cardiac impulse through the
heart, showing the time of ap...
Figure 1.11
Cardiovascular System
• Heart
– Electrocardiogram
• Recorded at the surface of the body
• A graphic representation of the ...
Electrocardiogram
• Figure 1.12 (next slide)
– Normal electrocardiogram
Depolarization
Figure 1.12
leading to
ventricular
contraction
Repolarization of
ventricles

Depolarization leading

to atr...
Cardiovascular System
• Blood Vessels
– Blood vessels operate in a closed-circuit system.
– The arterial system carries bl...
Distribution of Blood
• Figure 1.13 (next slide)
– The slide shows the arterial (right) and venous (left)
components of th...
Figure 1.13
Cardiovascular System
• Blood Vessels
– Arteries
– Capillaries
– Veins
Cardiovascular System
• Blood
– Hemoglobin transports oxygen and serves as an
acid–base buffer.
– Red blood cells facilita...
Key Point
• The cardiovascular system transports
nutrients and removes waste products while
helping to maintain the enviro...
Section Outline
• Respiratory System
– Exchange of Air
– Exchange of Respiratory Gases
Respiratory System
• Figure 1.14 (next slide)
– Gross anatomy of the human respiratory system
Figure 1.14
Respiratory System
• Exchange of Air
– The amount and movement of air and expired gases
in and out of the lungs are contro...
Expiration and Inspiration
• Figure 1.15 (next slide)
– The slide shows contraction and expansion of the
thoracic cage dur...
Figure 1.15
Respiratory System
• Exchange of Respiratory Gases
– The primary function of the respiratory system is the
basic exchange ...
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  • This is a sectional view of a muscle fiber
  • Chapter 1 structure and function of the muscular, neuromuscular, cardiovascular, and respiratory syste

    1. 1. chapter Structure and and Respiratory Muscular, Neuromuscular, Cardiovascular,Function of the Systems 1 Structure and Function of the Muscular, Neuromuscular, Cardiovascular, and Respiratory Systems Gary R. Hunter, PhD, CSCS, FACSM Robert T. Harris, PhD
    2. 2. Chapter Objectives • Describe the macrostructure and microstructure of muscle. • Describe the sliding-filament theory. • Describe the characteristics of different muscle fiber types. • Describe the characteristics of the cardiovascular and respiratory systems. • We will focus on the muscular and neuromuscular systems, review pages 1319 on your own (heart and lungs)
    3. 3. The Muscular System • ....DesktopESS 2600 VideosHuman Body Pushing The Limits E1 part 2.mp4
    4. 4. Muscular System • Macrostructure and Microstructure – Each skeletal muscle is an organ that contains muscle tissue, connective tissue, nerves, and blood vessels. – Fibrous connective tissue, or epimysium, covers the body's more than 430 skeletal muscles.
    5. 5. Muscle Belly Epimysium (deep facia) Fasciculus Endomysium Sarcolemma Sarcoplasm Myofilaments Myofibril (actin & myosin Perimysium Single muscle fiber Nucleus Tendon
    6. 6. Epimysium • The epimysium encases the muscle • All of the various layers of CT (endomysium, perimysium and the epimysium blend and are contiguous with the tendon). • Tendon: Attaches the muscle to the bone (it is much stronger than muscle tissue)
    7. 7. Fasiculi • Each fasiculi may consist of up to 150 fibers. • Each muscle fiber is surrounded by a connective tissue known as endomysium. • The fasiculi themselves are surrounded by connective tissue known as perimysium. – Think of this as the connective tissue within the muscle
    8. 8. Muscle Belly Epimysium (deep facia) Fasciculus Endomysium Sarcolemma Sarcoplasm Myofilaments Myofibril (actin & myosin Perimysium Single muscle fiber Nucleus Tendon
    9. 9. Muscle Fibers • Muscle fibers (also known as cells) are about the same diameter as a strand of human hair and can reach lengths as long as the muscle itself • Muscle fibers are made up of many myofibrils bundled together • Again, what myofilaments do we find in the myofibrils? • Strategically arranged actin and myosin
    10. 10. Muscle Fiber
    11. 11. Mitochondrion Opening to T-tubule Sarcoplasm T-tubule Myofibril Sarcolemma Sarcoplasmic reticulum
    12. 12. Muscle Contraction • What is the smallest “contractile unit” of skeletal muscle? – The sarcomere • Sarcomeres are lined up in series along the length of the myofibril – (remember: myofibrils make up each muscle fiber, so simultaneous contraction of the sarcomeres within all of the myofibrils leads to muscle cell shortening)
    13. 13. Figure 1.4
    14. 14. Muscular System • What is the Sliding-Filament Theory of Muscular Contraction? – The sliding-filament theory states that the actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling the Z-lines toward the center of the sarcomere and thus shortening the muscle fiber. – Sliding Filament Theory
    15. 15. Figure 1.5
    16. 16. (Review) Nervous system activation of a muscle Tropomyosin
    17. 17. AP
    18. 18. Contraction of a Myofibril – (a) In stretched muscle the I-bands and H-zone are elongated, and there is low force potential due to reduced cross-bridge–actin alignment. – (b) When muscle contracts (here partially), the I-bands and H-zone are shortened. – (c) With completely contracted muscle, there is low force potential due to reduced cross-bridge–actin alignment.
    19. 19. Neuromuscular System Motor Unit • The nervous system works via electrical impulses (action potentials), it signals the muscle to contract by sending action potentials to the muscle • What is a motor unit? – A motor unit consists of a motor neuron and the muscle fibers it innervates. – There are typically several hundred muscle fibers in a single motor unit.
    20. 20. Figure 1.2
    21. 21. The Nervous System is Creepy
    22. 22. Key Point • The discharge of an action potential from a motor nerve signals the release of calcium from the sarcoplasmic reticulum into the myofibril, this allows the “cross bridges” of the myosin to attach to actin. • Using the energy from ATP, tension can now be developed in muscle.
    23. 23. Section Outline • Neuromuscular System – – – – – Activation of Muscles Muscle Fiber Types Motor Unit Recruitment Patterns During Exercise Preloading Proprioception • Muscle Spindles • Golgi Tendon Organs
    24. 24. Neuromuscular System • • Activation of Muscles What chemical is released following an action potential? – Arrival of the action potential at the nerve terminal causes the release of acetylcholine. Once a sufficient amount of acetylcholine is released, an action potential is generated across the sarcolemma, and the fiber contracts. – What determines the level of muscular control. – Hand vs. Thigh • Muscles that function with great precision may have as few as one muscle fiber per motor neuron. • Muscles that require less precision may have several hundred fibers served by one motor neuron.
    25. 25. Neuromuscular System
    26. 26. ACTIVATION OF MUSCLES (neuromuscular junction) Once enough acetylcholine crosses the neuromuscular junction, the action potential is transmitted and the muscle contracts This occurs because the sarcolemma (muscle cell membrane), then T-tubule depolarizes and the sarcoplasmic reticula releases calcium
    27. 27. All-or-none principle • All of the muscle fibers in the motor unit contract and develop force at the same time. There is no such thing as a motor neuron stimulus that causes only some of the fibers to contract. Similarly, a stronger action potential cannot produce a stronger contraction.
    28. 28. Stimulated Motor Unit • Twitch, twitch summation, and tetanus of a motor unit: – a = single twitch – b = force resulting from summation of two twitches – c = unfused tetanus – d = fused tetanus
    29. 29. Neuromuscular System • Muscle Fiber Types – Type I (slow-twitch) – Type IIa (fast-twitch) • Type IIab (fast-twitch); now named as Type IIax • Type IIb (fast-twitch); now named as Type IIx – Type IIx are “true” fast-twitch fibers and are highly if not 100% glycolytic in nature – All other Type II fibers are oxidate and glycolytic hybrids
    30. 30. Table 1.1
    31. 31. MUSCLE FIBER TYPES • Postural muscles are typically composed of a higher percentage of type 1 fibers • Whereas larger muscles (quadriceps) have a mixed composition
    32. 32. Key Point • Motor units are composed of muscle fibers with specific morphological and physiological characteristics that determine their functional capacity. • Motor neurons, motor units and/or muscle fibers can be characterized as type .. Motor units are always the same type (you won’t find a motor neuron innervating both type I and type II fibers)
    33. 33. Neuromuscular System • Motor Unit Recruitment Patterns During Exercise – The force output of a muscle can be varied through change in the frequency of activation of individual motor units or change in the number of activated motor units.
    34. 34. Table 1.2
    35. 35. Neuromuscular System • Preloading – Occurs when a load is lifted, since sufficient force must be developed to overcome the inertia of the load • Proprioception – Information concerning kinesthetic sense, or conscious appreciation of the position of body parts with respect to gravity – Processed at subconscious levels
    36. 36. Neuromuscular System • How Can Athletes Improve Force Production? – Recruit large muscles or muscle groups during an activity. – Increase the cross-sectional area of muscles involved in the desired activity. – Preload a muscle just before a concentric action to enhance force production during the subsequent muscle action. – Use preloading during training to develop strength early in the range of motion.
    37. 37. Key Point • Proprioceptors are specialized sensory receptors that provide the central nervous system with information needed to maintain muscle tone and perform complex coordinated movements.
    38. 38. Neuromuscular System • Proprioception – Muscle Spindles • Also known as intrafusal fibers • Muscle spindles are proprioceptors that consist of several modified muscle fibers enclosed in a sheath of connective tissue.
    39. 39. Muscle Spindle • Figure 1.7 – When a muscle is stretched, deformation of the muscle spindle activates the sensory neuron, which sends an impulse to the spinal cord, where it synapses with a motor neuron, causing the muscle to contract. • Example: If you are being stretched by your trainer and they push the muscle a little too far/fast .. What is your natural reaction?
    40. 40. Figure 1.7
    41. 41. Neuromuscular System • Proprioception – Golgi Tendon Organs (GTO) – Where are GTOs located? • Golgi tendon organs are proprioceptors located in tendons near the myotendinous junction. • They occur in series (i.e., attached end to end) with extrafusal muscle fibers.
    42. 42. Golgi Tendon Organ • What happens when you lift something that is far too heavy? – When an extremely heavy load is placed on the muscle, discharge of the GTO occurs. – The sensory neuron of the GTO activates an inhibitory interneuron in the spinal cord, which in turn synapses with and inhibits a motor neuron serving the same muscle.
    43. 43. Figure 1.8
    44. 44. Neuromuscular System • Older Muscle – Muscle function is reduced in older adults. – Reductions in muscle size and strength are amplified in weight-bearing extensor muscles. – Muscle atrophy with aging results from losses in both number and size of muscle fibers, especially Type II muscle fibers. – Inactivity plays a major role but cannot account for all of the age-related loss of muscle and function.
    45. 45. Section Outline • Cardiovascular System – Heart • Valves • Conduction System • Electrocardiogram – Blood Vessels • Arteries • Capillaries • Veins – Blood
    46. 46. Cardiovascular System • Heart – The heart is a muscular organ made up of two interconnected but separate pumps. • The right ventricle pumps blood to the lungs. • The left ventricle pumps blood to the rest of the body.
    47. 47. Heart and Blood Flow • Figure 1.9 (next slide) – Structure of the human heart and course of blood flow through its chambers
    48. 48. Figure 1.9
    49. 49. Cardiovascular System • Heart – Valves • Tricuspid valve and mitral (bicuspid) valve • Aortic valve and pulmonary valve • Valves open and close passively, depending on the pressure gradient – Conduction System • Controls the mechanical contraction of the heart
    50. 50. Electrical Conduction System • Figure 1.10 (next slide) – The electrical conduction system of the heart
    51. 51. Figure 1.10
    52. 52. Cardiac Impulse • Figure 1.11 (next slide) – Transmission of the cardiac impulse through the heart, showing the time of appearance (in fractions of a second) of the impulse in different parts of the heart
    53. 53. Figure 1.11
    54. 54. Cardiovascular System • Heart – Electrocardiogram • Recorded at the surface of the body • A graphic representation of the electrical activity of the heart
    55. 55. Electrocardiogram • Figure 1.12 (next slide) – Normal electrocardiogram
    56. 56. Depolarization Figure 1.12 leading to ventricular contraction Repolarization of ventricles Depolarization leading to atrial contraction
    57. 57. Cardiovascular System • Blood Vessels – Blood vessels operate in a closed-circuit system. – The arterial system carries blood away from the heart. – The venous system returns blood toward the heart.
    58. 58. Distribution of Blood • Figure 1.13 (next slide) – The slide shows the arterial (right) and venous (left) components of the circulatory system. – The percent values indicate the distribution of blood volume throughout the circulatory system at rest.
    59. 59. Figure 1.13
    60. 60. Cardiovascular System • Blood Vessels – Arteries – Capillaries – Veins
    61. 61. Cardiovascular System • Blood – Hemoglobin transports oxygen and serves as an acid–base buffer. – Red blood cells facilitate carbon dioxide removal.
    62. 62. Key Point • The cardiovascular system transports nutrients and removes waste products while helping to maintain the environment for all the body’s functions. The blood transports oxygen from the lungs to the tissues for use in cellular metabolism, and it transports carbon dioxide from the tissues to the lungs, where it is removed from the body.
    63. 63. Section Outline • Respiratory System – Exchange of Air – Exchange of Respiratory Gases
    64. 64. Respiratory System • Figure 1.14 (next slide) – Gross anatomy of the human respiratory system
    65. 65. Figure 1.14
    66. 66. Respiratory System • Exchange of Air – The amount and movement of air and expired gases in and out of the lungs are controlled by expansion and recoil of the lungs.
    67. 67. Expiration and Inspiration • Figure 1.15 (next slide) – The slide shows contraction and expansion of the thoracic cage during expiration and inspiration, illustrating diaphragmatic contraction, elevation of the rib cage, and function of the intercostals. – The vertical and anteroposterior diameters increase during inspiration.
    68. 68. Figure 1.15
    69. 69. Respiratory System • Exchange of Respiratory Gases – The primary function of the respiratory system is the basic exchange of oxygen and carbon dioxide.

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