B3.3 Muscle and Motility Flashcards

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1
Q

Give some examples of internal movement in organisms

A
  • Peristalsis in the gut
  • ventilation in the lungs
  • ## movement in cytoplasm
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2
Q

Most plants are…

A

Sessile

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2
Q

Give an example of a motile organism adapted to locomotion

A

Bar-tailed godwits migrating from siberia to new zealand using wings for flight and doubling their body’s fat reserves before the journey.

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2
Q

Explain muscle contraction in terms of actin and myosin:

A

Actin is pulled towards the center of sarc by myosin, myosin has heads that can attach to the binding sites on actin, these heads undergo a cycle of binding to form a cross-bridge, pulling the actin myosin by abt 10nm then detaching and swiveling to the next binding site.

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3
Q

Example of sessile animal:

A
  • Coral reefs that can extend their tentacles into the water when they filter-feeding, but can’t move to a new location.
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4
Q

Give the order of organization for muscle fibers:

A

Muscle fiber, myofibril, sarcomere, actin, myosin

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5
Q

Dark band

A

The center of a sarcomere that contains many myosin filaments that overlap with six equidistant actin filaments.

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6
Q

Roles of Titin in muscle contraction and relaxation:

A
  • Releases potential energy when it recoils during muscle contraction, increases amount of force that a muscle can exert.
  • Connects the end of myosin filaments in the correct position of the six parallel actin filaments.
  • Prevents overstretching of the sarcomere.
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7
Q

What type of muscles are skeletal muscles composed of?

A

Striated Muscle fibers

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8
Q

Neuromuscular junction

A

The synapse between a motor neuron and a muscle fiber.

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9
Q

What neurotransmitter is used in a synapse between a synapse and a muscle fiber?

A

Acetylcholine

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10
Q

What features of a motor neuron allow it to stimulate simultaneous contractions in a group of muscle fibers?

A
  • It has branches that form neuromuscular junctions with hundreds of different muscle fibers.
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11
Q

Motor Unit

A

One motor neuron together with all the muscle fibers that it stimulates.

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12
Q

What does the motor unit pattern achieve?

A

Coordinated contraction of a muscle with as few motor neurons as possible.

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13
Q

Skeleton

A

Hard framework that supports and protects an animal’s body.

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14
Q

Exoskeletons

A

Tough plates of chitin that cover most of the body surface in anthropoids such as spiders, crustaceans, and insects.

15
Q

Endoskeleton

A

Bones in vertebrates 3ady

16
Q

What is the role of skeletons?

A

They facilitate movement by providing an anchorage for muscles and acting as levers.

17
Q

Which attachment of muscle causes movement?

A

The insertion at the fulcrum of 2 bones, not the orgin.

18
Q

Describe the adaptations that come with the need for maximum force:

A

Short limb —> energy load is close to the fulcrum of th limb.

19
Q

Describe the adaptations that come with the need for maximum movement and low force:

A

Longer limb —> Energy load is far from fulcrum

20
Q

Where do bones meet? 👂🫷

A

JOINTS 🔥🔥

21
Q

Where do bones meet? 👂🫷

A

JOINTS 🔥🔥

22
Q

Bones in synovial joints

A

An anchorage for muscles and ligaments shaped to allow a range of movements.

23
Q

Muscles in synovial joints

A

Cause movement at a joint by contracting and shortening the orgin and insertion of a a muscle on opposite sides of a joint.

24
Q

Tendons in synovial joints

A

Tough collagen-rich cords of tissue that attach muscle to bone and transmit force from contractions.

25
Q

Cartilage in synovial joints

A

Tough, smooth tissue covering bone at joints to prevent friction, absorb shocks, and prevent fractures.

26
Q

Ligaments in synovial joints

A

Tough cords of tissue with much collagen that prevent movements that would dislocate the joints.

27
Q

Joint capsule in synovial joints:

A

Tough ligamentous covering that seals the joint, holds in synovial fluid and prevents dislocation.

28
Q

Hinge joints

A
  • Allow movement in one plane: flexion (bending) and extension (straightening), the elbow and knee.
29
Q

Ball-and-socket joint

A

Moves in three planes: protraction/retraction/abduction/adduction, and rotation, the hip.

30
Q

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

A
  • A goniometer by computer analysis of images.
31
Q

Give 4 reasons for the importance of locomotion:

A

Foraging for food, escaping danger, searching for a mate mate, migration.

32
Q

Examples of importance if locomotion in honeybees:

A
  • Fly through flowers for nectar and pollen
  • Fly back to their colony during storms to seek safety.
  • Male bees fly at 10-40m to mate with a virgin queen not they find her.
  • A swarm of bees migrating as a colony
33
Q

Importance of locomotion in salmon:

A
  • Swim to catch prey of small fish and large invertebrates.
  • Swim to escape bluefin tuna and swordfish predators.
  • Search for a female laying eggs in spawning grounds to shed sperm there.
  • Migrate young from river to sea then back to river as adults to breed.
34
Q

How are marine mammals adapted to streamlining (minimize resistance to motion):

A
  • Widest near the front and tapering towards the rear, causing less drag.
  • Flipper, dorsal fins, and flukes with teardrop profile in transverse section which reduces drag.
  • Hairless skin to reduce friction.
35
Q

How are marine mammals adapted for locomotion?

A
  • Flippers used for steering instead of front legs.
  • Tail Lukes (lobes to right and left) to increase thrust when moved.
  • Dorsal fin to prevent rolling (stability)
  • blubber for buoyancy
36
Q

How are marine mammals adapted for periodic breathing between dives?

A
  • Airways closed during dives using the nostrils or blowhole.
  • Airways reinforced with rings of cartilage and smooth muscle to ensure ventilation can restart quickly after a dive.