Movement Flashcards
1
Q
What do bones and exoskeletons do?
A
- They provide anchorage for muscles and act as levers, they provide support for the body and facilitate movement
- Mammals have internal bones (endoskeleton) to support their body inside, tissues surround bones
- Other organisms have external skeleton (exoskeleton) found outside the organism to protect the internal tissues
2
Q
What organisms have exoskeletons?
A
- Crustaceans, insects, arachnids, molluscs, centipedes
3
Q
What do muscles do regarding physics?
A
- Provide a pivot point, skeletons act as levers transferring the size and direction of force
- Levers have a point of effort (force), point of load and a pivot point called fulcrum
- The force and load go in opposite directions except if they are at equilibrium (both down)
- Muscle contraction, force does up, everything else (load) goes down
- Joints are the fulcrum
4
Q
How do muscles work antagonistically?
A
- Muscles are stimulated by nerve impulses from motor neurons
- Muscles are flexible but do not stretch, they can only contract or pull, cannot push, this is a limitation
- Hence work in pairs, when one pulls in one direction, the other pulls in the opposite direction
5
Q
Explain the antagonistic action in biceps and triceps.
A
- To raise the lower arm, bicep contracts, triceps relaxes, the arm flexes around the joint
- This bring triceps into full length sot that it can contract again
- To lower the lower arm, triceps contracts and bicep relaxes
6
Q
Explain the antagonistic action in insect legs.
A
- Legs adapted to allow jumping
- Legs separated into tarsus (lower), tibia (middle), femur (upper)
- Muscles connect tibia and femur: extensor muscle and flexor muscle
- When preparing to jump, the flexor (biceps) contracts and extensor relaxes (leg is Z shaped)
- To jump up, extensor contracts and flexor relax
7
Q
What are synovial joints and what are their function?
A
- Synovial joint: where two bones connect, allow high range of motion
- Joints allow structural stability, by allowing certain movements but not others
1. Joint capsule that seals the joint space, provides stability by restricting the range of movements
2. Cartilage, lines bone surface, allows smooth movement and prevents friction
3. Synovial cavity filled with synovial fluid, provides O2 and nutrition to cartilage which reduces friction, produced by synovial membrane (surrounds joint) - Possible movements: flexion, extension, rotation, abduction (away from body) and adduction (towards body)
8
Q
Give 4 examples of joints and what their movement allows.
A
- Knee (hinge): flexion and extension
- Elbow (hinge): flexion and extension
- Hip: flex, extend, rotate, sideways, back
- Shoulder: abduction, adduction, flexion and extension
9
Q
Be able to draw an elbow joint
A
10
Q
Explain the structure of an elbow joint.
A
- Articulated synovial joint, joint where two moving bones meet encapsulated in synovial fluid
- Humerus bone: anchorage point for biceps and triceps
- Triceps: extends joint
- Biceps: flexes joint
- Radius bone: anchorage point for biceps
- Ulna bone: anchorage point for triceps
- Joint capsule: consisting or the synovial membrane encapsulating the joint with synovial fluid, prevents dislocation
- Synovial fluid: lubricates the join, prevent friction between cartilage at the end of 2 bones
- Cartilage: smooth tissue that covers the ends of the bones, absorbs shock and helps reduce friction
11
Q
Explain the structure of skeletal muscle fibres.
A
- These muscles are attached to the skeleton and aid in movement
- The cells are elongated, contain many nuclei and mitochondria
- Muscles are a collection of fibres that are striated, stripy appearance
- The fibres are surrounded by sacrolemma
- Sacrolemma: single plasma membrane, repeating units, contain actin filaments and myosin filaments
12
Q
What does each muscle fibre contain?
A
- Sepcialised endoplasmic reticulum called sacroplasmic reticulum which stores calcium and conveys signals to all parts of the fibre at once
- Specialised cytoplasm called sacroplasm contains mitochondria for aerobic respiration
- Myofibrils (dots), bundles of actin and myosin filaments that slide past each other at contraction
- Sacrolemma (membrane) has deep tube-like projections form outer surface, called T-tubules
13
Q
What are myofibrils?
A
- Located in the sarcoplasm
- Contains thick filaments myosin and thin filaments actin
- They are arranged in a particular order, creates bands and lines
- Cylindrical in shape
- Myofibril is divided into sacromeres, single contractile unit
14
Q
Be able to draw a sacromere.
A
15
Q
Explain the structure of a sacromere.
A
- Z-lines: mark either end of sacromere
- Actin: joined to z-lines and is thinner than myosin
- Myosin: crossheads visible and thicker than actin
- Light bands (around z-lines) and dark bands (where filament overlap)
