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Chapter 1: Structure and Function of Body Systems Flashcards

1
Q

How do muscles exert force on external objects?

A

Muscles can only pull, not push. However, through the system of bony levers, muscle pulling forces can be manifested as either pulling or pushing forces against external objects.

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2
Q

What does the axial skeleton consist of?

A

The axial skeleton consists of the skull (cranium), vertebral column (C1 through the coccyx), ribs, and sternum.

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3
Q

What bones are included in the appendicular skeleton?

A

The appendicular skeleton includes the shoulder girdle, arms, wrists, hands, pelvic girdle, legs, ankles, and feet.

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4
Q

What are joints?

A

Joints are junctions of bones where movement occurs.

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5
Q

What are the three types of joints?

A
  1. Fibrous joints (e.g., skull sutures) - no movement
  2. Cartilaginous joints (e.g., intervertebral discs) - limited movement
  3. Synovial joints (e.g., elbow and knee) - considerable movement
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6
Q

What are the three types of synovial joints?

A
  1. Uniaxial joints (e.g., elbow) - movement about one axis
  2. Biaxial joints (e.g., ankle and wrist) - movement about two perpendicular axes
  3. Multiaxial joints (e.g., shoulder and hip) - movement about three perpendicular axes
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7
Q

What are the five regions of the vertebral column?

A
  1. Cervical - 7 vertebrae
  2. Thoracic - 12 vertebrae
  3. Lumbar - 5 vertebrae
  4. Sacral - 5 fused vertebrae
  5. Coccygeal - 3 to 5 vertebrae forming the tailbone
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8
Q

What is the epimysium?

A

A fibrous connective tissue that covers skeletal muscle and is continuous with tendons.

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9
Q

What are the two muscle attachment points to bones?

A
  1. Proximal - Closer to the trunk
  2. Distal - Further from the trunk
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10
Q

What is a motor unit?

A

A motor unit consists of a motor neuron and the muscle fibers it innervates.

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11
Q

What is the sarcoplasm?

A

The cytoplasm of a muscle fiber, containing contractile components, enzymes, and organelles like mitochondria and the sarcoplasmic reticulum.

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12
Q

What are the two primary myofilaments in muscle contraction?

A
  1. Myosin - Thick filaments with globular heads forming cross-bridges
  2. Actin - Thin filaments in a double helix structure
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13
Q

What is the smallest contractile unit of muscle?

A

The sarcomere.

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14
Q

What is the Sliding Filament Theory?

A

The theory that actin filaments slide over myosin filaments, pulling Z-lines toward the center of the sarcomere, shortening the muscle fiber.

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15
Q

What happens in the resting phase of the Sliding Filament Theory?

A

Little calcium is present in the myofibril, so very few myosin cross-bridges are bound to actin.

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16
Q

What triggers muscle contraction in the Excitation-Contraction Coupling Phase?

A

Calcium binds to troponin, causing a shift in tropomyosin, exposing binding sites on actin for myosin attachment.

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17
Q

What provides energy for the contraction phase of muscle movement?

A

The breakdown of ATP by myosin ATPase provides energy for the power stroke.

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18
Q

What must happen for a muscle to relax?

A

Calcium must be pumped back into the sarcoplasmic reticulum, preventing actin-myosin binding.

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19
Q

What are the two ways to increase muscle force output?

A

(1) Increasing the frequency of motor unit activation (twitch summation), (2) Recruiting more motor units.

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20
Q

How do small muscles primarily increase force output?

A

By increasing the frequency of motor unit activation (twitch summation).

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21
Q

How do large muscles primarily increase force output?

A

By recruiting additional motor units.

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22
Q

How does motor unit recruitment differ between endurance and high-intensity activities?

A

Slow-twitch units dominate endurance activities, while fast-twitch units contribute more in high-intensity efforts.

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23
Q

Why do untrained individuals struggle to fully activate their fast-twitch motor units?

A

They lack neural efficiency and maximal recruitment ability, limiting force production.

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24
Q

What are proprioceptors?

A

Specialized sensory receptors in muscles, tendons, and joints that provide information about body position and movement.

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25
What is kinesthetic sense?
The ability to perceive body position and movement relative to gravity, aided by proprioceptors.
26
How is proprioceptive information processed?
Both consciously and subconsciously, allowing for coordinated movement and posture control.
27
What are muscle spindles?
Proprioceptors within muscles that detect changes in muscle length and rate of stretch.
28
What is the function of muscle spindles?
They activate motor neurons to initiate muscle contraction when a muscle is stretched.
29
Why do muscles that require precise movements have more muscle spindles?
To allow for fine control of muscle activation and movement adjustments.
30
What is an example of a muscle spindle reflex?
The knee-jerk reflex, where tapping the patellar tendon stretches muscle spindles, causing the quadriceps to contract.
31
What are Golgi Tendon Organs (GTOs)?
Proprioceptors located in tendons that detect muscle tension and inhibit excessive contraction.
32
How do GTOs function to prevent muscle injury?
When tension is too high, they send inhibitory signals to motor neurons, reducing muscle contraction.
33
How do muscle spindles and GTOs differ in function?
Muscle spindles facilitate muscle activation, while GTOs inhibit it to prevent excessive tension.
34
How does resistance training affect GTO inhibition?
The motor cortex can override GTO inhibition, allowing trained athletes to generate greater force.
35
What are three ways athletes can improve force production?
(1) Lifting heavy loads to enhance neural recruitment, (2) Increasing muscle cross-sectional area, (3) Performing explosive multi-joint exercises to recruit fast-twitch fibers.
36
What are the primary roles of the cardiovascular system?
To transport nutrients, remove waste, and help maintain the body's internal environment.
37
What are the two circulatory divisions of the heart, and what are their functions?
(1) Pulmonary circulation (right side): Pumps blood to the lungs. (2) Systemic circulation (left side): Pumps blood to the body.
38
What are the two types of heart chambers, and what are their functions?
(1) Atria: Receive blood and deliver it to ventricles. (2) Ventricles: Provide the main force to circulate blood.
39
What are the two types of heart valves, and what are their functions?
(1) Atrioventricular (AV) valves: Prevent backflow into atria. (2) Semilunar valves: Prevent backflow into ventricles.
40
What are the two atrioventricular (AV) valves, and where are they located?
(1) Tricuspid valve: Between right atrium & right ventricle. (2) Mitral (bicuspid) valve: Between left atrium & left ventricle.
41
What are the two semilunar valves, and where are they located?
(1) Aortic valve: Between left ventricle & aorta. (2) Pulmonary valve: Between right ventricle & pulmonary artery.
42
How do heart valves function?
They open and close passively based on pressure differences to prevent blood backflow.
43
What is the function of the SA node?
It is the heart’s intrinsic pacemaker, initiating rhythmic electrical impulses.
44
What is the function of the AV node?
It delays the impulse before transmitting it to the ventricles, allowing atrial contraction.
45
What is the pathway of electrical conduction in the heart?
SA node → AV node → AV bundle (Bundle of His) → Left & right bundle branches → Purkinje fibers.
46
How does the sympathetic nervous system affect heart rate?
It increases heart rate by accelerating SA node depolarization (chronotropic effect).
47
How does the parasympathetic nervous system affect heart rate?
It slows SA node discharge, reducing heart rate.
48
What are the normal, bradycardic, and tachycardic heart rate ranges?
Normal: 60-100 bpm, Bradycardia: <60 bpm, Tachycardia: >100 bpm.
49
What does an electrocardiogram (ECG) measure?
The electrical activity of the heart.
50
What does the P-wave represent in an ECG?
Atrial depolarization, leading to atrial contraction.
51
What does the QRS complex represent in an ECG?
Ventricular depolarization, leading to ventricular contraction.
52
What does the T-wave represent in an ECG?
Ventricular repolarization (recovery phase).
53
What are the two main components of the circulatory system?
(1) Arterial system: Carries blood away from the heart. (2) Venous system: Returns blood to the heart.
54
What is the function of arteries?
They transport blood from the heart under high pressure.
55
What is the function of arterioles?
They regulate blood flow to capillaries by constricting or dilating.
56
What is the primary function of capillaries?
To facilitate the exchange of oxygen, nutrients, and waste between blood and tissues.
57
Why do veins have thin, muscular walls?
Because they operate under low pressure and can act as blood reservoirs by constricting or dilating.
58
What is the function of venous one-way valves?
To prevent retrograde blood flow and aid in venous return to the heart.
59
What are the primary functions of blood?
Oxygen transport, carbon dioxide removal, and acid-base balance.
60
What is hemoglobin, and what are its functions?
An iron-containing protein in red blood cells that transports oxygen and buffers hydrogen ions.
61
How does carbonic anhydrase contribute to carbon dioxide removal?
It catalyzes the reaction between CO₂ and water, aiding in CO₂ transport.
62
What is the skeletal muscle pump?
A mechanism where muscle contractions compress veins, aiding in blood return to the heart.
63
Why should individuals move after exercise to prevent blood pooling?
Movement activates the skeletal muscle pump, helping maintain venous return and preventing blood pooling in the lower extremities.
64
What is the primary function of the respiratory system?
The exchange of oxygen (O₂) and carbon dioxide (CO₂).
65
What are the three main functions of the nasal cavity?
(1) Warming the air, (2) Humidifying the air, (3) Purifying the air.
66
What is the function of the trachea?
It serves as the first-generation respiratory passage, conducting air to the bronchi.
67
What are the second-generation respiratory passages?
The right and left main bronchi.
68
What is the function of bronchioles?
They are smaller branches of the bronchi that lead to the alveoli, where gas exchange occurs.
69
Where does gas exchange occur in the respiratory system?
In the alveoli.
70
How many generations of airway branching occur before air reaches the alveoli?
Approximately 23 generations.
71
What controls lung expansion and recoil?
The movement of the diaphragm and the elevation or depression of the ribs.
72
Do lungs expand and recoil on their own?
No, they are acted upon by surrounding structures.
73
What happens during inspiration (inhalation)?
The diaphragm contracts, creating negative pressure that draws air into the lungs.
74
What happens during expiration (exhalation)?
The diaphragm relaxes, and the elastic recoil of the lungs expels air.
75
What additional muscles are involved in forced expiration?
The abdominal muscles and internal intercostals.
76
Name the primary muscles involved in inspiration.
External intercostals, sternocleidomastoids, anterior serrati, and scaleni.
77
Name the primary muscles involved in expiration.
Rectus abdominis, external & internal obliques, transversus abdominis, and internal intercostals.
78
What is pleural pressure?
The pressure between the lung and chest wall pleura.
79
How does pleural pressure change during inspiration?
It becomes more negative, aiding in lung expansion.
80
What is alveolar pressure?
The pressure inside the alveoli when the glottis is open.
81
What must happen to alveolar pressure for air to flow in during inspiration?
It must fall below atmospheric pressure.
82
What must happen to alveolar pressure for air to flow out during expiration?
It must rise above atmospheric pressure.
83
What percentage of total energy expenditure is used for breathing at rest?
3-5%.
84
What percentage of total energy expenditure is used for breathing during heavy exercise?
8-15%.
85
When should athletes seek physician evaluation for breathing issues?
If they experience airway resistance problems, such as exercise-induced asthma.
86
How does gas exchange occur in ventilation?
Oxygen diffuses from alveoli to pulmonary blood, while carbon dioxide diffuses from blood to alveoli.
87
What drives the diffusion of gases in the lungs?
The kinetic energy of molecules and the difference in partial pressures.
88
How does oxygen move from the alveoli to the blood?
It diffuses down its concentration gradient due to a higher partial pressure in the alveoli than in the pulmonary capillaries.
89
How does carbon dioxide move from the blood to the alveoli?
It diffuses down its concentration gradient due to a higher partial pressure in the pulmonary capillaries than in the alveoli.
90
How fast does gas exchange occur in the lungs?
Almost instantaneously.
91
What types of exercise benefit respiratory muscle function?
Both endurance and resistance exercises.
92
Why do resistance exercises help train respiratory muscles?
They engage the diaphragm and abdominal muscles for stabilization and increased intra-abdominal pressure.
93
When is specific respiratory muscle training necessary?
After surgery or prolonged bed rest when normal breathing patterns are compromised.

CSCS (2 decks)

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