Locomotion Flashcards
Scapula attached to the trunk via extrinsic muscles. (slides across trunk allowing an increase in stride length).
what is synsascrosis?
- Latissimus dorsi
- Pectorals
- subclavius
- trapezius
- rhomboids
What are the extrinsic muscles responsible for retraction of the forelimb?
- Brachiocephalicus
- Trapezius
- Serratus
What are the extrinsic muscles responsible for protracting in forelimb ?
Pectoral muscles
What muscle(s) responsible for adduction between limbs?
- Trapezius
- rhomboids
- Serratus ventralis
- Infra/supraspinatus
What are the extrinsic muscles responsible for scapula rotation and elevation?
accessory nerve
what nerves innervate superficial extrinsic muscles?
branches of the brachial plexus
which nerves innervate deep extrinsic muscles?
- Loss/reduction of clavicle
- coracoid reduced
- synsasacrosis
what are the adaptations of the thoracic girl in the horse.
Pectoral branch from brachial plexus
Which nerves innervate the pectoral muscle
- triceps branchii
- deltoids
- teres major and minor
What muscles causes shoulder flexion ?
- supraspinatus
- infraspinatus
- coracobrachialis
- brachiociphalicus
- Biceps branchii
What muscles cause shoulder extension?
- coracobrachialis
- subscapularis
- teres major and minor
- deltoids
- Infaspinatus & supraspinatus
Which muscles are responsible for shoulder adduction/abduction and support?
-Biceps branchii
-brachialis
-carpal and digital flexors
musculo-cutaneous,median and ulnar
What are the muscles responsible for elbow flexion and the nerve thats innervates it?
-Triceps branchii
-carpal and digital flexors
Radial nerve
What muscles are responsible for the extension of the elbow and which nerve innervates it?
Flexor carpi radialis
flexor carpi ulnaris
What are the muscles responsible for carpal flexion?
Extensor carpi radialis
extensor carpi ulnaris
what are the muscles responsible for carpal extension?
Flexor digitorum superficialis
flexor digitorum profundis
What are the muscles responsible for flexion in the digits?
Extensor digitorum communis
Extensor digitorum lateralis
what are the muscles responsible for extension in the digits?
name some thoracic limb adaptations in the horse?
- scapula curved and slides along rib cage
- humerus large and robust
- Radio-ulnar articulation reduced or absent
what are the muscles responsible for hip extension (caudo-lateral)?
- Gluteal muscles (deep gluteal, middle gluteal & superficial gluteal)
- Hamstrings (semimembranous, semitendonous & biceps femoris)
What muscles are responsible for hip flexion (cranio-lateral)?
- Rectos femoris (Only part of the quadracep muscle that acts on the coxafemoral joint)
- gluteal superficialis
- Iliacus
What are the muscles responsible for adduction at the hindelimb?
- Gracilis
- Adductors
What muscles are responsible for abduction on the hindelimbs?
- Sartorius
- Gluteal muscles
- Piriformis
What muscles cause flexion at the stifle joint?
- Hamstings
- Gastrocnemius
- Poplitus
What muscles are responsible for extension at the stifle joint?
-Quadriceps (3 vasti & rectos remoris
What muscles cause flexion at the hock (metacarpalphalangial joint)?
Cranial tibial
What muscles are responsible for extension at the hock ?
- Gastrocnemius
- Soleus
What is reciprocal Apparatus?
This is cause by the action of the peroneus tertius and the flexor digitorum superficialis. This allows for simultaneous flexion at the hock and stifle joints. Energy saving mechanism.
what nerves innervate the pelvic limb structures?
Lumbrosacral plexus
- femoral
- sciatic
- gluteal
- obturator
What is patella locking and what adaptation allows it ?
Patella locking is the locking of the stifle joint allowing for minimal energy consumption to maintain a standing stance. The trochlear of the horse has two ridges unlike other species, a medial and lateral aspect. The medial ridge is larger and the patella articulates here and locking is enabled.
Describe the process of endochondrial ossification..
Periosteum forms around hyaline cartilage. Osteogenic cells differentiate into osteoblasts and secrete osteoid which forms the bone collar. The primary ossification centre (centred cartilage) begins to ossify leading to cavitation. blood vessels from periosteum pass through lamellar and poke through nutrient foramen. remaining cartilage broke down by osteoclasts and osteoblast secrete osteoid. blood vessels then bud into the cartilage in the epiphysis forming secondary ossification centres. Osteoclast break down cartilage and spongy bone is formed. EGP and articular cartilage are left behind
Describe intramembranous ossification..
perichondrial cells lay down bone collar. Mesenchyme cells become osteoblast and osteoclasts. osteoblast that get stuck in the bone matrix become osteocytes.
Describe the process of bone growth..
- Reserve chondrocytes begin to proliferate and mature
- Chondrocytes undergo hypertrophy
- Cartilage is calcified
- Organisation of bony trabeculae begins and osteoclastic resorption
What are the hormonal factors affecting one growth/remodelling..
- Dietary calcium and phosphate needed for hydroxyapetite
- absorption of ca+2 dependant on calcitriol, only made in the presence of vitamin D
- Calcititonin/Parathyroid hormone regulate ca+2 metabolism
- Insulin, GH and thyroxin promote bone growth
- Oestrogen promotes osteoclast activity
Why is ATP required for muscle contraction?
1) ATP hydrolysis re energises myosin head, providing energy for myosin head movement and force generation
2) Allows for repeated contraction (releases myosin head from actin)
3) Ca-ATPas in sarcoplasmic reticulum hydrolyses ATP to take back up ca+2 after contraction
what are the Sources of ATP
1) Phosphorylation of ADP by creatine phosphate
- very rapid -amount made limited by amount of CP in cell -short duration
2) oxidative phosphorylation of ADP in mitochondria in mitochondria (aerobic) -moderate levels, slow -uses blood borne fuels (glucose,02,fatty acids) as well as glycogen in muscles
3) phosphorylation of ADP in cytosol (anaerobic)
- lactic acid by product - requires glycogen and/or glucose
Describe the different types of muscle fibres..
type I- slow twitch, red in colour high levels of myoglobin. resistant to fatigue. large amount of mitochondria
Type IIa- Fast oxidative. uses both aerobic and anaerobic metabolism. moderate force fatigue
Type IIb- fast glycolytic, lower levels of myoglobin and mitochondria giving a white colouration. produce ATP at a slow rate but break it down rapidly. short sharp burst followed by fatigue.
What is hysteresis?
Energy lost by tendons during elastic cycle. heat dissipation.
What is mechanical safety factor?
Ratio of failure stress to typical stress experienced during normal locomotion (typically 2-4)
Explain how bone is tough and strong by using elastic and plastic regions…
Elastic region of bone represents the normal functional limit for stress, bone recovered when bone is unloaded. Plastic region gives bone its toughness, allowing large amounts of energy to be absorbed, This however causes micro fractures which must be healed by remodelling. If the amount of stress overlaps the the rate of remodelling then fracture occurs.
What are the differences in the femur between the dog and horse?
- Greater trochanter less pronounced in dog, less muscle attachment
- Trochlear has 2 ridges in the horse, medial & lateral.
- Horse has a third trochanter where the superficial gluteal muscle attaches
