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IB Biology HL > B3.3 Muscle and mobility > Flashcards

B3.3 Muscle and mobility Flashcards

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1
Q

What is movement?

A

Movement is one of the 8 characteristics of life(MRHMGREN) but movement can either refer to movements that can take place within the bode (e.g. peristalsis) or by moving an organism from one place to another(locomotion)

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2
Q

What is a sessile organism?

A

Sessile organism (e.g. barnacles or corals or planta-mimosa pudica) do not perform locomotion – they remain in a fixed position but move individual body parts.

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3
Q

What is a motile organism?

A

Motile organism move around while feeding within their territory – some further distances than others.
E.g. mammals, bacteria, squid/octopus

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4
Q

What do muscles fibres contain?

A

Muscle fibers contain many parallel myofibrils, which consist of a series of sarcomeres.

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5
Q

What are sarcomeres?

A

A sarcomere is the repeating unit of a muscle cell.

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6
Q

What cause the contraction of sarcomeres?

A

The contraction of sarcomeres, and therefore a muscle, is due to the sliding of actin and myosin filaments.

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7
Q

What are sarcolemma and sarcoplasma, in respect to the sliding filament model of contraction?

A

The sarcolemma and sarcoplasma are specific adaptations of the cell membrane and cytoplasm, respectively.

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8
Q

What is the sarcoplasmic reticulum?

A

A specialised (modified) endoplasmic reticulum, the sarcoplasmic reticulum, is a fluid filled system of membranous sacs surrounding the muscle myofibrils.

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9
Q

What is the function of the sarcoplasmic reticulum?

A

Wrapped around myofibrils, its function is to store calcium ions, and comes to action when conveying a signal to contract all parts of the muscle fibres.

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10
Q

What does the sarcolemma contain?

A

The sarcolemma has multiple tunnel-like extensions that penetrate the interior of the cell, called T-tubules.

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11
Q

What are between the myofibrils?

A

Between the myofibrils are large number of mitochondria, which provide ATP needed for contraction.

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12
Q

What causes the pattern of light and dark bands in sarcomeres?

A

The pattern of light and dark bands in sarcomeres is due to a precise and regular arrangement of actin and myosin filaments.

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13
Q

What happens during a muscle contraction?

A

A muscle contraction shortens each sarcomere and therefore the overall length of the muscle fibre. The contraction occurs by sliding of actin and myosin filaments.

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14
Q

Describe the changes that occur to the sarcomere during muscle contraction/relaxation.

A

When muscle fibers contract the sarcomere length shortens and the Z-discs move closer together. When the muscle is relaxed, the sarcomere length is longer.

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15
Q

What are skeletal muscles composed of?

A

A bundle of striated muscle fibres, each of them stimulated by a motor neuron.

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16
Q

What are muscle fibres?

A

Each muscle fibre is a multinucleated cell containing numerous myofibrils, which are highly ordered assemblages of thick myosin and thin actin filaments.

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17
Q

What causes muscles to contract or relax?

A

The release of calcium from sarcoplasmic reticulum (motor neuron–>nerve impulse) triggers muscle contraction.

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18
Q

What is the neuromuscular junction?

A

At the synapse (neuromuscular junction) the stimulus is converted into a chemical signal using acetylcholine as a neurotransmitter. One motor neuron with multiple branches connecting to a number of muscle fibre. This results in a coordinated contraction.

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19
Q

What are muscle fibres composed of?

A

Myofibrils which contain sarcomeres, and it contains a specialised cytoplasm called sarcoplasm.

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20
Q

What is a sarcomere?

A

The basic contractile unit of a muscle containing actin(thin filament) and myosin (thick filament).

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21
Q

Inside a sarcomere there are protein filaments called actin and myosin. These two fibrous structures are largely responsible for facilitating a muscle contraction: Describe the features of the thick and thin protein filaments.

A

The thin filament is made up of two twisted chains of the globular protein actin.
The thick filament is made of many molecules of the protein myosin. Each myosin molecule has a fibrous tail and a globular head. It has an actin binding site and an ATPase binding site.

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22
Q

Explain how the sliding filament mechanism and cross-bridges of muscle fibres result in a muscle contraction.

A

The sliding filament theory explains contraction of a sarcomere. According to this theory, when a muscle is stimulated to contract, actin filaments slide over the myosin filaments towards centre of the sarcomere. This results in:
- 2-discs being pulled closer together. shortening sarcomere + resulting in overall shortening of muscle fibres
- H bands + I bands decrease length as actin is pulled inwards, overlapping more myosin + reducing area where only myosin or actin is present

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23
Q

How does a contraction begin and how does that result in sarcomere shortening?

A

Muscle contraction initiated by the brain via an action potential which causes an influx calcium ions that bind to troponin. Without electrical stimulation, myosin binding sites on the actin filaments are blocked by a thin + fibrous protein subunit called tropomyosin. Tropomyosin runs alongside the action filament preventing binding of myosin to actin + hence preventing contraction of muscle. Tropomyosin is associated with another protein subunit called troponin. When a muscle is stimulated by a motor neuron, calcium ions are released from sarcoplasmic reticulum, a specialized endoplasmic reticulum that is found in sarcoplasm (cytoplasm) of muscle cells. These calcium ions bind to the troponin causing it to undergo a conformational change –> troponin moves tropomyosin away from myosin binding site, allowing myosin to bind to actin.

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24
Q

Why do the sarcomere shorten?

A

The shortening of the sarcomere comes about by the cocking of the myosin heads, when ADP and Pi is released. The breaking of the cross-bridges can only occur when a fresh molecule of ATP re-charges the myosin head.

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25
Q

What is the function of tropomyosin?

A

In addition to the contractile filaments myosin and actin, the myofibril also contains troponin protein complexes and tropomyosin fibers.
Tropomyosin covers the myosin binding sites, effectively preventing attachment of the myosin head. During a contraction, Ca2+ ions bind to troponin, which moves away the tropomyosin fibres.

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26
Q

What is titin?

A

Titin is the largest polypeptide being composed of 34350 amino acids. It is elastic and acts as a molecular spring.
Titin connects myosin filamints to the Z-discs.

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27
Q

What are the functions and contributions of titin to muscle contraction?

A

Titin connects myosin filaments to the Z-discs. It stores potential energy when it is stretched and releases it when it recoils - thereby adding to the force of contraction. It also prevents overstretching of the sarcomere and it holds the myosin filaments in place surrounded by 6 actin filaments.

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28
Q

What is the role of antagonistic muscle?

A

Energy is needed to stretch titin and therefore lengthen the muscle when relaxing. Energy cannot be supplied by the muscle itself because muscles can only exert force when contracting. The energy is therefore provided by another muscle called the antagonist.
E.g. In the elbow joint, the triceps and biceps muscles are an antagonistic pair. The biceps flexes the forearm, the triceps extends the forearm.

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29
Q

Compare exoskeleton and endoskeleton.

A

An exoskeleton takes over the function of bones for muscle attachment in arthropods.
An endoskeleton- internal skeleton.

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30
Q

What is the purpose of a skeleton?

A

-support
-shape
-protection

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31
Q

What is the function of skeleton, muscle, joints in an animal?

A

The skeleton of an animal, together with the muscles attached across the joints, functions as a system of levers. Each joint acts as a pivot point (fulcrum). A muscle is normally attached to two parts of the skeleton – one is the origin one is the insertion. By acting as levers, bones can change the size and direction of a force.

32
Q

What is effort?

A

The force applied (when the muscle contracts) is called the effort.

33
Q

What is a lever?

A

A lever is a beam or rigid rod pivoted at a fixed hinge.

34
Q

How does the effort (the force) applied to a lever change with the distance away from the function (the joint)?

A

The further away from the fulcrum the effort is applied, the greater the leverage; that is, the smaller the force that is required to raise the load.

35
Q

What is an example of a first class lever in the human body?

A
36
Q

What is an example of a second class lever in the human body?

A
37
Q

What is an example of a third class lever in the human body?

A
38
Q

What determines the range of movements of joints?

A

The specific anatomical construction of a joint determines the range of movement.

39
Q

What are the six main types of joints?

A

-Planar joint
- Hinge joint
- Pivot joint
- Condyloid joint
- Saddle joint
- Ball and socket joint

40
Q

What is a synovial joint?

A

This is where two bones with cartilage and synovial fluid in between join.

41
Q

What cartilaginous joints?

A

Cartilaginous jointsare joints in which the bones are connected by cartilage.

42
Q

What is the range of motion?

A

The range of motion refers to the different movements that can be carried out at a joint e.g. rotation, abduction, adduction

43
Q

What is the type, range of directional movement, types of movements of the elbow joint?

A
  1. Elbow joint
  2. Hinge joint
  3. Angular movement in only one direction
  4. Flexion + Extension
44
Q

What is the type, range of directional movement, types of movements of the radio-ulnar joint(elbow)?

A
  1. Radio-ulnar joint (elbow)
  2. Pivot joint
  3. Movement in all rotational direction (360°)
  4. Rotations (pronation-supination)
45
Q

What is the type, range of directional movement, types of movements of the hip joint?

A
  1. Hip-joint
  2. Ball and socket
  3. Angular movement in many directions
  4. flexion, extension, abduction, adduction, circumduction, rotation
46
Q

What is the type, range of directional movement, types of movements of the knee joint?

A
  1. Knee joint
  2. Hinge joint
  3. Angular movement in only one direction
  4. Flexion and Extension
47
Q

Annotate this diagram.

A
48
Q

What is the function of bones in a hip joint?

A

Bones provide an anchorage for muscles and ligaments. By their shape, bones guide types of movements that can occur at a joint.

49
Q

What is the function of cartilage in a hip joint?

A

Cartilage is tough, smooth tissue that covers bone at the joint. It helps to prevent friction by preventing contact between regions of bone that might cause bones to fracture.

50
Q

What is the function of synovial fluid in a hip joint?

A

Synovial fluid fills a cavity in the joint between the cartilages on the ends of the bones. It lubricates the joint, helping to prevent the friction that would occur if the cartilages were dry and touching.

51
Q

What is the function of ligaments in a hip joint?

A

Ligaments are tough cords of tissue containing large quantities of the protein collagen. They prevent aberrant movements that would dislocate or damage the joint. It seals the joint and holds in the synovial fluid and it helps to prevent dislocation.

52
Q

What is the function of muscle in a hip joint?

A

Muscles provide the forces that cause movement at the joint.

53
Q

What is the function of tendons in a hip joint?

A

Tendons attach muscle to bone. Like ligaments they are composed of living tissue, with large quantities of extracellular collagen, which has high tensile strength. Some tendons are long and cord-like so forces can be transmitted over the distance between the muscle and the bone to which the tendon attaches it.

54
Q

How can the range of motion at a joint be measured?

A

The range of motion at a joint can be measured and investigates using a goniometer. This simple device can be used to measure the angle of movement at a given joint.

55
Q

What can affect muscle stretching?

A

Muscle stretching and other factors (hormones, biological sex, age…) can all affect the range of motion.

56
Q

What is an example of antagonistic muscle action?

A

The intercostal muscles are a good example for an antagonistic pair. While the external muscles contract to move the ribcage up, the internal muscles stretch, storing potential energy in the sarcomere protein titin. When the internal muscles contract the ribcage moves down, stretching the external muscles.

57
Q

What are the reasons for locomotion?

A

-foraging for food
-escaping from danger
-searching for a mate
-migration

58
Q

What is foraging?

A

Foraging is the act of searching for and collecting food.

59
Q

What are the different forms that foraging can take?

A

Foraging behaviour can take many forms:
- some animals may graze vegetation
- some may search for fruits, nuts and other plant-based food
- some animals may actively hunt and capture prey
- some may scavenge for food that has already been killed and discorded

60
Q

What are the foraging patterns of horses?

A

Horse (Equs Caballus) will forage for around 16 hrs/day, feeding on grass, herbs and other vegetation. In wild horses will cover large distance per day in search of fresh vegetation, spending several minutes in one spot and then moving to next spot.

61
Q

What is the effect on domestic horses not being able to follow their foraging patterns?

A

Domesticated horses that are confined to small spaces may exhibit repetitive movements or stress behaviours. E.g. crib biting- grabbing and pulling objects with their teeth when they are unable to engage with natural foraging activities.

62
Q

What are the foraging patterns of bees?

A

Bees (Genus Apis) are insects that forage for nectar, pollen and water to bring back to their hive to feed their colony and rains their young. When foraging, bees usually fly from flower to flower collecting nectar and pollen with their specialised mouthpiece and body hair.

63
Q

What do bees rely on when foraging?

A

Bees rely on their sense of sight and smell to locate brightly coloured and scented flower. They can also communicate to other bees using pheromones and complex dance that communicates location of resources to other bees in hive.

64
Q

What are escape behaviours?

A

Escape behaviours are usually fast and robust, enabling animals to swiftly avoid threats such as predators or other hazards in their surrounding.

65
Q

What escape behaviours do elephants have?

A

Elephants (genus Loxodenta) have been known to detect infrasonic sounds of tsunamis before tsunami hits coast. In response, elephants flee to safety of higher grounds.

66
Q

How is locomotion related to escape behaviours?

A

Animals use various types of locomotion to avoid their predators, depending on their physical abilities and environmental conditions. Common ways to avoid predators include running, jumping, flying, climbing and swimming.

67
Q

How is locomotion related to searching for mate?

A

Most animals reproduce sexually, which requires fusion of male and female gametes. Thus, most animals will need to move to a location where members of opposite sex will be present. The more they can move, the more likely they are to find a suitable partner.

68
Q

What are examples of the relationship between locomotion and searching for a mate?

A

Some species have a low population density, which is particularly true for large territorial animals e.g. tigers. Tigers may have limited opportunity to interact with members of opposite sex within their own territory, particularly are habitat destruction and poaching threatens the population size. Tigers commonly traverse huge distances in search of a mate.

69
Q

What is migration?

A

Migration refers to large-scale seasonal movement of an animal group from one place to another. Migration occurs in all major animal groups, including birds, mammals, insects, crustaceans, fish, reptiles and amphibians.

70
Q

What is an example of migration?

A

Great white shark is an endangered species found coastal and offshore waters off all major oceans- They are migratory species, alternating between breeding and foraging grounds. Researches often capture, tag and release to monitor their location and migratory behaviour. A recent study in NZ found make between Steward Island off NZ. Steward Island where food is plentiful, to move north tropical waters in winter, as far as 300km away.

71
Q

How does the airways help marine animals instead of a shared passageway between trachea and oesophagus?

A

Changes airways to allow periodic breathing between dives. Whales and dolphins have a specialized nostril called a blowhole on the top of their heads which allows them to breath without stopping or lifting their heads out of the water. Blowhole is covered by muscular flap which when contracted opens to allow air to enter and leave lungs. When released, covers and seals to prevent entry of water. Used for communication between dolphins and whales - producing clicks and whistles that allows them to conveys info.

72
Q

What adaptations to the body shape and surface minimizes resistance to motion?

A

Streamline bodies that minimise drag, allowing for efficient movement through the water. Marine mammals also often have a thick layer of blubber under their skin, which helps to smooth out their body shape, reducing drag as they move through the water.

73
Q

What is the blubber for in dolphins?

A

-smooth out body shape –> reducing drag
-buoyancy
-insulation cold water environments

74
Q

How are the flippers used in dolphins?

A

-positioned on sides of bodies which are usually long and narrow, and can by used for steering
-generate lift
-contributes to streamline shape

75
Q

How are the flukes used in dolphins?

A

-used steering and propulsion in water by moving up and down in a sweeping motion, as opposed to tails of fish, which move side to side

76
Q

How is dorsal fin used in dolphins?

A

-Stability helping the dolphin maintain balance and prevent rolling as it swims through the water. This is especially important for streamlined, efficient movement.
-Thermoregulation: The dorsal fin contains a network of blood vessels that help regulate the dolphin’s body temperature. Blood flow to the fin can increase to release heat when the dolphin is in warmer waters or decrease to conserve heat in cooler environments.
-Hydrodynamics: Positioned along the back, the dorsal fin enhances the dolphin’s hydrodynamic efficiency, reducing drag and allowing smoother, more controlled swimming.
-Communication and Identification: In some dolphin species, the shape, size, and marks on the dorsal fin can vary between individuals, acting as an identifier for other dolphins or researchers. Dolphins may also use their dorsal fin to signal or convey body language to other members of their pod.

IB Biology HL (14 decks)

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