Musculoskeletal System Flashcards
What is the locomotor system?
Musculoskeletal system that allows wide range of animal movement.
What are the components of the locomotor system?
Bones, joints and muscles.
Define cursorial.
Having limbs adapted for running.
What are the key adaptations of the locomotor system in cursorial animals?
- Reduced pectoral skeleton - allows more cranial/caudal movement.
- Elongation at proximal end of limb - scapula lies laterally.
- Elongation at distal end of limb - long metacarpals, walk on toes or hooves.
Describe how the pectoral skeleton reduced.
In cursors the clavicle is usually absent or vestigial; there is no skeletal component attaching the forelimb to the trunk.
How is the scapula attached to the body in a cursor?
Joint is purely muscular and is called a synsarcosis. This particular joint is called the omothoracic junction.
What is a consequence of increasing leg length?
Increase stride length - energy efficient way to cover the ground more quickly.
Define flexion.
Folding limb
Define protraction.
Moving limb forwards.
Define extension.
Stretching limb
Define retraction.
Moving limb backwards or fixing limb and moving trunk forwards relative to limb.
In which species is trunk contribution limited.
Herbivores with roughage diets e.g. horses –> rely more on limbs elongation.
In which species is trunk contribution higher.
Carnivores with small-volume, consuming meat diet have flexible trunks, multipurpose limbs e.g. cat.
What are the four gaits and their beats?
- Walk - 4 beat
- Trot - 2 beat
- Canter - 3 beat
- Gallop - 4 beat
Name and describe the two components of the domestic species internal skeleton.
- Axial skeleton - bones of vertebral column, skull and ribcage.
- Appendicular skeleton - all bones of fore and hind limbs.
Name the 4 main bone classifications.
- Flat
- Long
- Short
4 Sesamoid
Describe flat bones and give examples.
- Large surface area for muscle attachment.
- Protection of underlying structures.
- Scapula/pelvis
Describe long bones and give examples.
- Support and leverage in limbs
- humerus/femur
Describe short bones and give examples.
- Large range of movement
- Ant-concussive
- Carpus/tarsus
Describe sesamoid bones.
- Embedded in tendons
- Change in angle over bony surface –> redirect forces, reduce friction so prevent damage
Describe the general features of bones.
- Smooth surface areas: passage of structures/tendons
- Specific bony contours: provide site for attachment of important structures
- Rough surface areas: general muscle attachment
Define the periosteum.
- Covers outer surface of bone (except articular surfaces).
- Contains blood vessels and nerves.
- Important for fracture healing.
What are the epiphysis and diaphysis in a long bone?
Epiphysis: Ends of the bone, spongy for shock absorption.
Diaphysis: Shaft, compact for strength.
How do primary and secondary ossification centers differ?
Primary: Forms in diaphysis during fetal development.
Secondary: Forms in epiphyses after birth.
How do growth plates appear on radiographs?
In young animals: Visible as dark (radiolucent) lines.
In adults: Closed and fully ossified, no longer visible.
What are growth plates?
Growth plates, or epiphyseal plates, are areas of hyaline cartilage located between the ossification centres.
How do growth plates contribute to bone growth?
- Chondrocytes in the proliferation zone divide and push older cells toward the diaphysis.
- Older chondrocytes hypertrophy, the matrix calcifies, and osteoblasts lay down new bone, elongating the bone.
What are the structural components of skeletal muscle?
- Muscle fibers arranged in fascicles.
- Connected to bone via tendons.
- Rich blood supply and innervation.
What is the origin of a muscle?
The fixed or stationary attachment point of a muscle.
What is the insertion of a muscle?
The movable attachment point of a muscle.
How can muscles attach to bone?
- Directly to bone
- Via tendons
- Via aponeurosis (limited access to bone)
