Anatomy Quiz 2 myology and locomotion

Question 1

What are the three types of muscles

Answer 1

Smooth muscle, Cardiac muscle, skeletal muscle

Question 2

Smooth Muscle

Answer 2

Not striated; associated with viscera (gut, vessels, glands, etc.)
Example:: arrector pili muscles , the detrusor muscle

Question 3

Cardiac Muscle

Answer 3

Striated; musculature of the heart
The heart (myocardium) & the bases of the major blood vessels.

Question 4

Skeletal Muscle

Answer 4

Striated; generally attached to bone; usually under voluntary control
- Voluntary
- Striated
Skeletal muscle will not contract in the absence of a functional nerve supply (denervation atrophy occurs).

One neuron innervates a variable number of muscle fibers.

The neuron plus the muscle fibers it innervates constitute a motor unit. To produce a stronger contraction, the nervous system activates more motor units.
~ 50% of the body “the carcass”

Most attached to bone
Not limited to the skeleton.
Found in the pharynx, esophagus, & skin (i.e.. cutaneous trunci).

Question 5

Muscle Fiber

Answer 5

• Bound to the adjacent fibers to form bundles called fascicle.
• Multiple fascicle bound to other fascicles to form a muscle

  - With this arrangement, the contraction in one area of a muscle works in conjunction with contracting fibers elsewhere in the muscle.

The binding substance within muscles is the associated loose C.T.
Muscle fibers are within a connective tissue framework that is continuous with tendons

Question 6

Connective tissue components of skeletal muscle

Answer 6

Myofiber( muscle cell)

Endomysium: small amounts of loose c.t. surrounding individual muscle fiber

Fascicle‘bundle’ = groups of M. fibers

Perimysium loose connective tissue defining muscle fascicles .

Muscle is invested by a c.t. sheet

Epimysium= loose or dense connective tissue surrounding an entire muscle

Question 7

Structure of the Skeletal Muscle

Answer 7

These C.Ts merge at the end of the muscle “belly” to form the tendon (dense regular connective tissue – attach to bone.)

What is the importance of these c.t. arrangements?
To make sure they all contract simultaneously

Question 8

Joints of the Forelimb

Answer 8

Synsarcosis
Shoulder
Elbow
Carpus
(fetlock)
Digital

Question 9

Muscle Actions

Answer 9

Agonist
Antagonist
Synergist
Fixator

Question 10

Agonist

Answer 10

Prime Movers
Principal muscle(s) executing the particular joint movement
- Produces most of the force during a joint action when activated.
- Muscle activity involve change in the angle they bridge.
Exert action on distal joint
- Produces certain effect a (movement),
- Flexing the elbow -biceps brachii or brachialis!!
- (Origin: distal end of scapula; insert: end in radius and ulna)

Question 11

Antagonist

Answer 11

Actively opposing the prime mover

Maintains some tension on a joint; thus limits the range of the agonist (preventing excessive movement & joint injury)

Checks the action of the agonist
- Triceps vs biceps brachii

Question 12

Synergist

Answer 12

It assist the prime mover
Neither facilitate nor directly oppose a movement (may modify the action of agonist by eliminating unwanted side effect)
Assistant to agonist
Brachialis and Biceps brachii

Brachialis(synergist) is also a flexor, it helps the biceps brachii which is an agonist (flexor)
- Helps the biceps brachii by stabilizing the flextion

Question 13

Fixators

Answer 13

It prevents a bone from moving

Stabilize joints rather than to promote movement
-Biceps brachii and the extrinsic muscles
-(all synsarcosis muscles – attach the limb to the axial skeleton (sling) whole weight is suspended through those muscles )

Question 14

Naming Muscles

Answer 14

Attachments
- cleidobrachialis.
Cleido 🡪 Clavicle

Shape
- Teres minor
Rounded muscle (non-functional)

Size
- Teres major
Large. Along with latissimus dorsi

Function
- Supinator
Small in dogs, not used. Large in cats

Location/position
- Deep digital flexor (DDF) (SDF – Superficial digital flexor)

Number of heads
- Biceps brachii

Number of bellies
- Digastricus (open jaw of dog)

Question 15

Muscle Attachments

Answer 15

Accessory structures [necessary for muscle function]:
- tendons
- aponeurosis

Question 16

Tendons

Answer 16

Low metabolic activity (poorly vascularized)

Tough, but can be damaged by excessive pressure or friction, when change direction over bony prominences

D.R.C.T. in compact cylinder (tensile strength) attaching muscle to periosteum of bone

Question 17

Aponeurosis

Answer 17

Broad, flat tendon sheet-like union

Question 18

Forms of Protection for Tendons

Answer 18

Bursa
Tendon sheath

Inflammation of synovial bursae and sheath is common, and it is necessary to know their position and extends.
They occur precisely where they are required.

Question 19

Accessory Structures of Muscles

Answer 19

Retinaculum

Annular Ligaments

Sesamoid Bones

Question 20

Ligaments

Answer 20

NOT a structure of muscles:
It joins bone to bone

Question 21

Clinical Significance of Lipomas ( Mammary)

Answer 21

Tissue masses palpable from the skin surface

abnormal aggregates of normal fat (lipid cells) – with capsule around - “S/C, dogs,& cats”)
Spayed females
Well circumscribed – (contained within capsule)
Not life threatening – only cosmetic

Question 22

Palpable Features

Answer 22

) Acromion; “hammate & suprahammate in cat”;
b) greater tubercle;

Deeper palpation:
a) Spine of scapula;
b) tendon of origin of biceps;
c) deltoid tuberosity

a) Superficial cervical L. node (limb retracted)
b) Axillary L. node (enlarged), (limb protracted)

a) Olecranon “5th rib or 5th intercostal space)
Point of the elbow.

Question 23

Mammae

Answer 23

Vary from 8 - 12
Thoracic (2 pairs)
Abdominal (2 pairs)
Inguinal (one pair)

Pups nurse the caudal six mammae (best secretion)

Caudal 3 pairs, frequently involved in tumors, and mastitis.

Question 24

Mammary Neoplasia

Answer 24

Lumpectomy:
Removal of a mass or part of a mamma

Simple mastectomy:
Is excision of an entire gland

Regional mastectomy:
Is excision of the involved an adjacent glands

Question 25

Venipuncture

Answer 25

For purpose of withdrawing blood or injection

Cephalic vein and

External Jugular veins
Are important sites for Venipuncture.

Question 26

Extrinsic

Answer 26

(Pectoral Girdle)
At least one attachment (~origin) is external, i.e., to axial skeleton

Functions:
Sling the body between the forelimbs (serratus ventralis & deep pectoral)

Weight bearing (thoracic limb carries more weight about 60-70%, carry head, neck, thorax)

Stabilize the scapula

Deep pectoral: Sternum to humerus (weight)

Serratus ventalis: sternum to scapula (weight)

DORSAK Median raphe: supraspinus ligaments

Rhomboids: Medial raphe to scapula
Trapezius thoracis:

Question 27

Intrinsic Muscles

Answer 27

Both attachments are internal to limb bones

Question 28

Functions of Skeletal Muscle

Answer 28

Muscles provide motive power for:
Locomotion [movement]

Question 29

Movements of Animal body

Answer 29

Movement: most obvious function is to move the body, as in walking, running, writing, chewing, and swallowing.
Stimulation maintains a state of muscle contraction “tonus” for movement of blood & lymph.
Prevent unwanted movements (stabilizing joints)

Question 30

Posture

Answer 30

Skeletal muscles maintain posture by stabilizing the flexible muscles.
Certain muscles work in opposition to gravity.

Question 31

The Functions of Muscles

Answer 31

Muscles provide more power for locomotion

Question 32

Movement of Body contents (Muscles)

Answer 32

Respiration (diaphragm & intercostal)

Circulation

alimentation ( digestion - GI tract defecation, & urination. (movement of body contents)

Childbirth

Indication of emotional states
- Barking, facial expression (cutaneous muscles), raising hair, or waging tail

Control of body openings and passages
“ maintain continence”
- example : ring-like sphincter muscles ( eyelids pupils, mouth)

Generate heat by shivering
- homeostasis

Question 33

Bursa

Answer 33

A form of protection for tendons

Fluid-filled Cushions at danger sites:
- If only one aspect of tendon is at risk
- Bursa (bursa synovialis) small fluid-filled sacs located between tendons and stress points.

Infraspinatus go to greater tubercle of humerus.
Needs cushion 🡪 subtendious bursa

Question 34

Tendon Sheath

Answer 34

If a greater aspect of tendon is vulnerable this will be present

Fluid-filled cylinders surrounding tendons over stress points

Question 35

Retinaculum

Answer 35

condensed deep fascia over carpus or tarsus
Prevent ‘webbing’

Question 36

Annular Ligaments

Answer 36

Condensed deep fascia over the digits

Question 37

Sesamoid Bones ( Form of protection for tendons)

Answer 37

Grow (ossification) in tendons for extra strength at stress points.

Ossification of cartilage (even in embryo).

Move tendon away from axis.

Patella (kneecap):
- prevent wear and displaces tendon from axis of joint.
-(Remember: Ligament attaches bone to bone (patella to tibia)

Question 38

Clinical Significance of Infiltrate Lipoma

Answer 38

Unencapsulated fatty tumor (deep into tissue)

Deeply attached to muscle fascia

Question 39

Extrinsic Muscles role in movement

Answer 39

During progression, they resolve into antagonist groups that control the swing - Stride gate progression

Protraction – bring forward (cranially)
- All joints are extended
- End of stride

Retraction- bring back (caudally).
- Beginning of stride
- All joints are flexed

Question 40

Girdle Muscle groups

Question 41

Endomysium

Question 42

Epimysium

Question 43

Perimysium