Muscles

Question 1

which muscle type? why?

Answer 1

skeletal muscle. has striations, myofibrils, each cell is multinucleated (peripheral), with many nuclei distributed throughout its cytoplasm

Question 2

which muscle type? why?

Answer 2

cardiac muscle. microscopically has striations. individual cells are short & mononucleate

Question 3

which muscle type? why?

Answer 3

smooth muscle. no striations. mononucleated, short, spindle-shaped

Question 4

name the muscle architecture

Answer 4

1. strap muscle 2. spindle-shaped muscle 3. pennate muscle 4. bipennate muscle 5. multipennate muscle

Question 5

cross- sectional area of muscle provides what?

Answer 5

power

Question 6

what is Isometric contraction?

Answer 6

When tension is generated in a muscle, i.e. muscle tone is increased, but the muscle does not shorten

Question 7

what is Isotonic contraction?

Answer 7

When a muscle actually moves or shortens

Question 8

name the structures & briefly define

Answer 8

Origin – The starting point of a muscle is its origin. By convention this generally closest to the centre of the body. It moves the least during contraction

muscle belly - fleshy central area the belly that tapers to tendons at either end

Insertion – Distal end where a muscle inserts on bone

Aponeurosis (flat broad tendons) - An attachment of a flat muscle that is drawn out into a flat sheet

Question 9

This muscle runs from one region of the body to another. Thus the origin and insertion are in different parts of the body. type of muscle?

Answer 9

extrinsic muscle

Question 10

This muscle lies completely within one region of the body where they have their origin and insertion. muscle type?

Answer 10

intrinsic muscle

Question 11

Name some muscles with extrinsic origins & their functions

Answer 11

Trapezius - Draws the leg forward and protracts the limb

Pectorals – Adduct the limb and hold the forelimb against the body

Latissimus dorsi - Retracts the forelimb

Brachiocephalicus – When limb is on the ground it flexes the neck and bends the neck laterally; when the limb is not weight bearing it draws the foreleg forwards or protracts the limb (similar to trapezius)

Question 12

name the muscles & briefly describe their roles

Answer 12

Supraspinatus – Extends the shoulder and stabilises the shoulder joint

Infraspinatus: Flexes the shoulder joint and helps stabilise the shoulder joint

Triceps brachii – Extends the elbow joint

Biceps brachii – Flexes the elbow joint

Brachialis – Flexes the elbow joint

Question 13

name these muscles

Answer 13

Question 14

name these muscles

Answer 14

Question 15

name these muscles

Answer 15

Question 16

Muscles of the caudal aspect, main muscles of propulsion…what are they? describe their roles

Answer 16

Biceps femoris – Extends hip, flexes stifle and extends the hock

Semitendinosus – Extends hip, flexes stifle and extends the hock

Semimembranosus – Extends hip and flexes stifle

Question 17

Gluteal muscles. function?

Answer 17

hip extensors

Question 18

Tensor fascia latae. function?

Answer 18

Aid in extension of the hip

Question 19

name these muscles

Answer 19

Question 20

describe the function of intrinsic EXTENSOR GROUP muscles: cranial tibial, Long digital extensor, Fibularis longus, Lateral digital extensor

Answer 20

Cranial Tibial – flexes the hock and rotates the paw medially.

Long digital extensor – Flex tarsus and extend the digits.

Fibularis longus – flex tarsus and rotate paw medially.

Lateral digital extensor – Flex tarsus and extend lateral digits

Question 21

describe the function of intrinsic FLEXOR GROUP muscles: Gastrocnemius, Superficial digital flexor, Deep digital flexor

Answer 21

Gastrocnemius – By virtue of its origin extends the tarsus and flexes the stifle

Superficial digital flexor – Flex digits, extend the tarsus flex stifle

Deep digital flexor – Flex digits and extend tarsus

Question 22

name these muscles

Answer 22

Question 23

position & function of Epaxial muscles?

Answer 23

above the vertebral column. Arranged in three groups and function to support the spine, extend the vertebral column and allow lateral flexion

Question 24

position & function of Hypaxial muscles?

Answer 24

below the vertebral column. One region is associated with the neck, another with the back. The hypaxial muscles flex the neck and tail, and contribute to flexion of the vertebral column