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ANIMAL > Bones, Muscles & Levers (W4) > Flashcards

Bones, Muscles & Levers (W4) Flashcards

1
Q

Muscles?

A

= a group of muscle tissues that contract together to produce a force.

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2
Q

The 2 functions of muscles?

A

• To move the bones of the skeleton around.
• To connect to bone via tendons.

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3
Q

Muscle origin?

A

= the proximal base of the muscle.

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4
Q

Muscle insertion?

A

= where the distal end of the muscle connects to a bone or tendon.

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5
Q

What do we mean when we say that muscles work antagonistically?

A

We mean that they work in pairs of opposing motion.

eg. Seen in the biceps and triceps of the arm.

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6
Q

Benefit of muscles working antagonistically?

A

It provides a full range of motion.

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7
Q

Skeletal muscle tissue?

A

= one of three muscle tissue types that is involved in helping us move around.

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8
Q

Muscle fiber?

A

= a single cell that is made up of fibrils, which are made up of sarcomeres.

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9
Q

Skeletal muscle tissue layout/organization? (outer to inner)(4)

A

• Muscle.
• Muscle fibers.
• Fibrils/Myofibrils.
• Sarcomeres.

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10
Q

Sarcomeres?

A

= fundamental units of skeletal muscle that contain actin & myosin.

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11
Q

Primary filaments involved in muscle contraction? (2)

A

• Actin.
• Myosin.

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12
Q

Actin?

A

= thin muscle filaments that have binding sites.

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13
Q

How does muscle contraction occur?

A

During muscle contraction, myosin heads grab actin fiber & “pulls” itself along the actin.

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14
Q

Bone functions? (4)

A

• Supports the body.
• Allows the body to move via muscle attachments.
• Important for Ca & P metabolism.
• Site for erythrocyte production (hematopoesis).

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15
Q

What must the bone do to support the body?

A

Bone tissue must be able to resist the 4 types of forces, namely, compression, tension, torsion and shear forces.

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16
Q

What is the process of bone formation referred to as?

A

Ossification OR Osteogenesis.

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17
Q

Which law is bone remodeling related to?

A

Wolff’s Law.

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18
Q

Hematopoesis?

A

= red cell production.

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19
Q

Explain the hematopoesis graph? (2)

A

• Shows the most important parts of your skeleton to hematopoesis.

• Shows that as you get older, hematopoesis nolonger occurs in our long bones but in our rib cage, sternum & axial skeleton.

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20
Q

Types of forces that bone must resist? (4)

A

• Compression.
• Tension.
• Torsion.
• Shear.

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21
Q

Compression?

A

= force that acts on the long axis of the bone & pushes the ends closer together.

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22
Q

Eg of compression?

A

Effects of gravity on runners as they plant one leg & then other.

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23
Q

Tension?

A

= force that pulls the opposite ends of bone away from each other.

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24
Q

Eg of Tension?

A

Primate hanging from a branch by its arms.

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25
Q

Torsion?

A

= force that twists on bone along its long axis.

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26
Q

Shear?

A

= force where the movement is in opposite directions of the ends of bone, in the same plane.

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27
Q

Eg of Torsion?

A

Arm bones of professional bowlers & pitchers in baseball.

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28
Q

Eg of Shear?

A

When your feet are moving one way & you get tackled in the opposite direction.

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29
Q

Bone components? (2)

A

• 40% Collagen.
• 60% Hydroxyapatite.

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30
Q

Collagen properties? (3)

A

• Organic protein.
• Superb strength in tension.
• Flexible.

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31
Q

Hydroxyapatite properties? (4)

A

• Inorganic material.
• Superb strength in compression.
• Rigid.
• Contains Ca & P.

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32
Q

Bone Analogy?

A

Steel as it can resist torsion (in cables), compression (in tall buildings), tension (rear in prestressed concrete) & shear (edge of katana blade) due to it being a mixture of carbon and iron.

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33
Q

Why is bone called a heterogeneous material?

A

Because it is a mixture of 40% of collagen & 60% of hydroxyapatite which account for bone’s impeccable performance.

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34
Q

Bone structure? (3)

A

• Collagen.
• Hydroxyapatite.
• Other proteins.

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35
Q

Collagen function?

A

To form fibrils which is the scaffolding of the bone.

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36
Q

Fibrils?

A

= scaffolding of bone.

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37
Q

Hydroxyapatite function?

A

To be a deposit on the fibrils.

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38
Q

Other proteins function?

A

To serve as glue to bond mineralized fibrils.

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39
Q

Explain how the bone materials are combined?

A

• Collagen forms fibrils.
• Hydroxyapatite is then deposited on the fibrils.
• The other proteins then act as glue to bond the mineralized fibrils.

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40
Q

Why can bones be boiled to glue?

A
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41
Q

Analogy of bone structure?

A

Pool construction
- where the rebar (resists tension) forms a scaffold which cement (resists compression) is sprayed over.

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42
Q

Types of bone? (2)

A

• Cortical bone.
• Trabecular bone.

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43
Q

Cortical bone AKA?

A

Compact bone.

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44
Q

Trabecular bone AKA?

A

Spongy, cancellous bone.

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45
Q

Cortical bone?

A

= thin outer shell of all bones.

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46
Q

Cortical bone location?

A

Shafts of long bones.

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47
Q

Trabecular bone?

A

= interior cavity of most bones.

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48
Q

Trabecular bone location?

A

Heads of long bones.

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49
Q

Diaphyses?

A

= shafts of long bones.

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50
Q

Epiphyses?

A

= heads of long bones.

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51
Q

Cortical bone in terms of stress concentration?

A

Present at sites of maximal stress concentration.

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52
Q

Trabecular bone in terms of stress concentration?

A

Present at sites of less stress concentration.

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53
Q

Why Trabecular bone? (2)

A

● Bone is energetically costly to maintain therefore, it’s only deposited where stresses are very concentrated (cortical bone).

● To enable efficient beam mechanics as it predicts the stress concentrations of compression & tension on the surface of a beam & become more diffuse at ends of beam.

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54
Q

Organization of compact bone tissue (top to bottom)? (4)

A

• Harvesian system/Osteons.
• Central Harvesian canal.
• Lamellae of hydroxyapatite.
• Osteocytes in lacunae connected by canaliculi.

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55
Q

Harvesian system/Osteon?

A

= fundamental units of compact bone.

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56
Q

Osteon components? (3)

A

• Central Harvesian canal.
• Lamellae of hydroxyapatite.
• Osteocytes in lacunae.

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57
Q

Harvesian canal?

A

= carries the primary blood supply.

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58
Q

Lamellae of hydroxyapatite?

A

= organized layers of hydroxyapatite.

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59
Q

Osteocytes?

A

= cells that maintain the bone & live in lacunae.

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60
Q

Lacunae?

A

= small holes in which osteocytes live/are found.

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61
Q

Canaliculi?

A

= small canals that connect lacunae.

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62
Q

Special bone attribute?

A

Has high blood supply/vascularization due to Harvesian systems.

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63
Q

Bone development short explanation?

A

Bone is formed from embryonic mesoderm tissue & then develops from mesoderm in 2 ways, by endochondral replacement or by intramembranous ossification.

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64
Q

Types of bone development? (2)

A

• Endochondral bone.
• Intramembranous bone.

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65
Q

Endochondral bone AKA?

A

Replacement bone.

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66
Q

Intramembranous bone AKA?

A

Dermal bone.

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67
Q

Replacement bone locations? (3)

A

• Most of the limb bones.
• Vertebrae.
• Medial end of the clavicle.

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68
Q

Dermal bone locations? (2)

A

• Most of the skull bones.
• Lateral end of the clavicle.

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69
Q

Endochondral bone formation steps? (5)

A

● Mesoderm cells form a hyaline cartilage model of the bone.

● The outer shell ossifies to become “perichondral bone” & the cartilage begins to die.

● Blood vessels invade the bone of the diaphyses.

● Osteoblasts (bone-forming cells) arrive & form centers of ossification.

● Secondary ossification centers begin in the epiphyses.

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70
Q

Basically Endochondral bone formation? (4)

A

• Start with cartilage.
• Takes over cartilage.
• Replaces cartilage with bone.
• Replacement bone.

71
Q

Intramembranous bone formation steps? (4)

A

● Mostly ectoderm cells differentiate to become osteoblasts & begin an ossification centre.

● Osteoblasts secrete osteoid & osteoid mineralizes quickly (bone matrix is laid down).

● Blood vessels become trapped as the bone is laid down, & mesoderm is induced to condense on the surface of the ossification center.

● Bone remodeling reorganizes the developed bone.

72
Q

Basically Intramembranous bone formation? (2)

A

• No cartilage as initial medium.
• Osteoblasts appear spontaneously.

73
Q

Osteoid?

A

= the protein scaffolding for bone.

74
Q

Osteoblasts?

A

= bone-forming cells.

75
Q

How do osteoblasts build bone?

A

By secreting osteoid.

76
Q

Bone remodeling process? (2)

A

● All bone is initially laid down as woven bone which is irregularly structured.

● Gradually, woven bone is replaced by lamellar bone, which is stronger & oriented along stress lines.

77
Q

Bone types in bone remodeling? (2)

A

• Woven bone.
• Lamellar bone.

78
Q

Woven bone?

A

= bone that is laid down rapidly in an irregular way (hence its random appearance).

79
Q

Lamellar bone?

A

= bone that replaces woven bone in a much more ordered way.

80
Q

Purposes of bone remodeling? (2)

A

• For reorganization of bone.
• For repairing microfractures from stress.

81
Q

What would happen if microfractures were not repaired?

A

The small cracks would eventually weaken the skeleton & result in macrofractures.

82
Q

Specialized osteocytes involved in bone remodeling? (2)

A

• Osteoblasts.
• Osteoclasts.

83
Q

Osteoblasts?

A

= specialized osteocytes that build bone.

84
Q

Osteoclasts?

A

= specialized osteocytes that kill bone.

85
Q

Bone remodeling steps? (5)

A

● Areas of bone being remodeled are dissolved by osteoclasts releasing Ca & P back into the bloodstream.

● Osteoclasts then carve out little areas of bone.

● Osteoblasts are recruited to these areas from the bone marrow.

● Upon arrival to the excavation areas of bone, osteoblasts begin laying down osteoid that then mineralizes.

● Eventually, osteoblasts have fully replaced the damaged area.

86
Q

Wolff’s law?

A

= states that if the loading stress on a bone decreases, the bone mass will be lost (i.e., one should either use the bone or lose it).

87
Q

Why does Wolff’s law happen? (2)

A

• Bone is costly to maintain.
• Areas of higher stress need more strength.

88
Q

Egs of Wolff’s law? (2)

A

• Arms of tennis players [Non-playing arm vs Playing arm (more bone mass)].

• Bones of astronauts which lose mass at the rate of 1%/month.

89
Q

Osteoporosis?

A

= presence of porous bones that are caused by an imbalance between osteoblasts & osteoclasts.

90
Q

Result of osteoporosis?

A

Cortical bone becomes trabecular bone, leading to a decrease in bone density.

91
Q

Why should you go to the gym?

A

It’s because going to the gym prevents bone loss as it stresses your skeleton & makes it remodel and add more bone.

92
Q

What does FOP stand for?

A

Fibrodysplasia ossificans progressiva.

93
Q

FOP?

A

= condition caused by a mutation in a gene that makes it hard for the body to stop expressing BMP4.

94
Q

BMP4?

A

= gene that signals ossifications in the developing body but is usually switched off in most tissues.

95
Q

Brief FOP explanation?

A

Damage to a tissue leads to a repair response & as part of that response bone is laid down instead of the appropriate tissue.

96
Q

Skeletal muscle tissue components? (3)

A

• Muscle fibers.
• Fibrils/Myofibrils.
• Sarcomeres.

97
Q

Myosin?

A

= thick muscle filaments that have heads.

98
Q

Muscle contraction & relaxation analogue?

A
99
Q

Skeletal muscle tissue under the microscope?

A

Striations seen in the skeletal muscle tissue are due to a large amount of sarcomeres.

100
Q

Muscle architecture/muscle fiber orientation types? (2)

A

• Parallel muscle.
• Pennate muscle.

101
Q

Parallel muscle architecture attribute?

A

• Have less muscle strength.

102
Q

Parallel muscle fiber locations? (3)

A

• Sartorius.
• Biceps.
• Pectoralis major.

103
Q

Sartorius muscle?

A

= muscle that helps with bending your knees and hips & rotating the leg outward.

104
Q

Which is the most widest (larger angle) parallel muscle among the 3?

A

Pectoralis major.

105
Q

Pennate muscle architecture attributes? (2)

A

• Have physiological cross-sectional area.
• Have more muscle strength.

106
Q

Pennate muscle fiber locations? (3)

A

• Palmar interossei.
• Vastus intermedius muscle.
• Deltoid muscle.

107
Q

Palmar interossei?

A

= muscle between the carpals.

108
Q

Vastus intermedius muscle?

A

= muscle that enables knee extension (underneath the rectus femoris).

109
Q

What is muscle strength not dependent on?

A

Length of the sarcomeres.

110
Q

Muscle strength is dependent on what?

A

Number of sarcomeres contracting.

111
Q

What is muscle strength proportional to?

A

Cross-sectional area.

112
Q

Physiological cross-sectional area?

A

= the area measured by drawing a line perpendicular to the angle of the muscle fibers.

113
Q

Relationship between the Pennate muscle, muscle strength & physiological cross-sectional area?

A

As muscle gets more pennate, physiological cross-sectional area increases, muscle strength increases.

114
Q

Relationship between the pennate muscle, muscle strength & running speed?

A

More pennate muscle, More muscle strength, More body mass, Less running speed.

115
Q

Relationship between pennate muscle, contractile distance & muscle strength?

A

More pennate muscle + More contraction, Less muscle strength, Less contractile distance.

116
Q

Why do muscles contract?

A

Muscles contract to supply force & move joints.

117
Q

Contractile fibers loction/Site for contractions?

A

In the belly of the muscle/muscle belly.

118
Q

What does not contract?

A

Tendons.

119
Q

Muscle attributes in terms of movement? (2)

A

• Muscles must cross the joint they move.

• Muscles must work in antagonistic pairs to provide a full range of movement.

120
Q

Eg of Muscle attribute 1?

A

Biceps crosses the elbow joint.

121
Q

Eg of Muscle attribute 2 (i.e., Muscle antagonistic pair)?

A

Biceps & Triceps of the arm.

122
Q

Components of muscle & joint movement? (2)

A

• Agonist.
• Antagonist.

123
Q

Agonist?

A

= the contracted muscle.

124
Q

Agonist basically?

A

Agonist = Agony = Contraction.

125
Q

Antagonist?

A

= the relaxation muscle.

126
Q

Antagonist basically?

A

Antagonist = Anti-agony = Relaxation.

127
Q

Muscle directional terms? (4)

A

• Abduction.
• Adduction.
• Extension.
• Flexion.

128
Q

Abduction?

A

= to take away from the mid-line.

129
Q

Adduction?

A

= to bring closer to the mid-line.

130
Q

Extension?

A

= to increase the angle between two parts.

131
Q

Flexion?

A

= to decrease the angle between two parts.

132
Q

Abduction basically?

A

= abducting arms from the mid-line.

133
Q

Adduction basically?

A

= closing up.

134
Q

Explain the mystery question: What do the bull, the whippet & the baby have in common?

A

The bull, the whippet & the young German boy have defects in their myostatin genes.

135
Q

Myostatin?

A

= a protein that prevents overproduction of muscle by antagonizing muscle growth & differentiation.

136
Q

Why do we use the skeleton as a system of levers?

A

It helps us understand how vertebrate anatomy relates to function.

137
Q

Lever components? (3)

A

• Fulcrum.
• Input lever.
• Output lever.

138
Q

Fulcrum?

A

= rotation point.

139
Q

Input lever AKA?

A

In-lever.

140
Q

Input lever?

A

= where you apply force (distance).

141
Q

Output lever AKA?

A

Out-lever.

142
Q

Output lever?

A

= where the load is (distance).

143
Q

Thing to note for Basic lever mechanics?

A

Know how to diagram the basics, i.e., fulcrum, in-lever (distance) & out-lever (distance).

144
Q

Mechanical advantage?

A

= the ratio of the length of the in-lever to out-lever.

145
Q

MA<1 attributes? (3)

A

• The lever decreases your output force.
• Makes it harder to lift a load.
• High velocity.

146
Q

MA>1 attributes? (3)

A

• The lever amplifies your output force.
• Makes it easier to lift a load.
• Low velocity.

147
Q

Problem with MA?

A

The tradeoff between strength (power to move mass) & the velocity (distance of movement).

148
Q

How to explain the MA problem?

A

Explain the fact that with low MA, comes high Velocity (long distance of movement) & with high MA, comes low Velocity (short distance of movement).

149
Q

MA in terms of strength?

A

= strength needed to move the load/weight.

150
Q

Lever calculation formula?

A

Lo * Fo = Li * Fi.

151
Q

What does each equation component symbolize? (4)

A

Lo = output lever length.
Li = input lever length.
Fo = output force.
Fi = input force.

152
Q

Lever calculation formula use?

A

To calculate force needed to lift loads/weights.

153
Q

Name the 3 classes of levers?

A

• Class 1 lever.
• Class 2 lever.
• Class 3 lever.

154
Q

What do the lever classes involve?

A

The arrangements of the load, the fulcrum & the input lever.

155
Q

Class 1 lever fulcrum position?

A

In between the input force & the output force.

156
Q

Class 1 lever MA?

A

0<MA< infinity.

157
Q

Inorganic egs of Class 1 lever? (2)

A

• See-saw.
• Pulling nails with a hammer.

158
Q

Biological eg of Class 1 lever?

A

Triceps brachii.

159
Q

Explain how Triceps brachii is a Class 1 lever?

A

Triceps pulls on the olecranon process (input lever), the elbow joint is the fulcrum & the hand is holding a load (output lever).

160
Q

Class 2 lever fulcrum position?

A

At the tip (fulcrum, output lever, input lever).

161
Q

Class 2 lever attributes? (4)

A

• Short out-lever.
• Long in-lever.
• Input > Output.
• Load is in between fulcrum & input lever.

162
Q

Class 2 lever MA?

A

MA>1.

163
Q

Inorganic eg of Class 2 lever?

A

Wheelbarrow.

164
Q

Biological eg of Class 2 lever?

A

Gastrocnemius (standing on your tiptoes.).

165
Q

Explain how Gastrocnemius is a Class 2 lever?

A

Tiptoes are fulcrum, out-lever is the distance between the ankle & tiptoes, & the in-lever is the distance between the heel & tiptoes (larger distance).

166
Q

Class 3 lever fulcrum position?

A

At the tip (fulcrum, input lever, output lever).

167
Q

Class 3 lever attributes? (4)

A

• Short in-lever.
• Long out-lever.
• Input < Output.
• Load is at far opposite end of fulcrum.

168
Q

Class 3 lever MA?

A

MA<1.

169
Q

Inorganic eg of Class 3 lever?

A

Braai tongs.

170
Q

Biological egs of Class 3 lever? (2)

A

• Biceps brachii.
• Quadriceps muscles at the knee.

171
Q

Explain how Biceps brachii is a Class 3 lever?

A

Fulcrum is elbow joint (or olecranon process?), in-lever is the proximal insertion of the muscle & out-lever is the distal insertion of the muscle.

172
Q

Things to mention when explaining how animals use levers to move limbs in different ways? (5)

A

• Does MA increase or decrease?

• How does MA increase or decrease?

• What is the Impact of positions of the muscles & limbs/bones?

• What is the tradeoff?

• The impact on extension & flexion?

173
Q

Solve Archimedes quote?

A

Lo = distance Earth to Moon (3.8×10⁸ m).
Fo = mass of Earth (6×10²⁴ kg).
Fi = your mass (60 kg).
Li = ?

Substitute into equation.

Li = 3.8 × 10³¹ m.

174
Q

Lever system application in the Medieval times by Archimedes?

A

Flaming trebuchet projectile.

ANIMAL (21 decks)

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