Muscles

Question 1

Describe the basic structural and functional characteristics of the three types of muscle tissue.

Answer 1

Skeletal muscle - attached to bones, striated, mainly/some voluntary

Cardiac muscle - wall of the heart, striated, involuntary

Smooth muscle - walls of hollow structures, not striated, involuntary

Question 2

What is the function of skeletal muscle?

Answer 2

Organized into striations, cells are surrounded by connective tissue coverings

Question 3

What is the function of the cardiac muscle?

Answer 3

Filaments with each fiber are striated, individual fibers connected by intercalated discs, they may contain gap junctions that allow action potentials to be transmitted from one cell to another - aids in coordinated of the heart’s pumping action

Question 4

What is the function of the smooth muscle?

Answer 4

Filaments within each muscle fibre are striated = greater ability to shorten/stretch, occasionally small channels between individual muscle fibers that allow action potential to be transmitted between cells

Question 5

What relation to muscles do the following words have: origin, belly, action, innervation?

Answer 5

Origin - the attachment does not move - proximal attachment
Intersection - the attachment that moves - distal attachment

Belly - the “fleshy” portion of the muscle in the middle

Action - movement(s) that occur when the muscle contracts

Innervation - the motor nerve supply to the muscle

Question 6

Define the common terms used in muscle names that describe direction.

Answer 6

Rectus - parallel to midline

Transverse - perpendicular to midline

Oblique - diagonal to midline

Question 7

Define the common terms used in muscle names that describe size.

Answer 7

Maximus - largest
Minimus - smallest
Longus - long
Brevis - short
Latissimus - longest
Magnus - large
Major - larger
Minor - smaller
Vastus - huge

Question 8

Define the common terms used in muscle names that describe shape.

Answer 8

Deltoid - triangular
Trapezius - trapezoid
Serratus - saw-toothed
Rhomboid - diamond-shaped
Orbicularis - circular
Pectinate - comblike
Piriformis - pear-shaped
Platys - flat
Quadratus - squared/four-sided
Gracilis - slender

Question 9

Define the common terms used in muscle names that describe action.

Answer 9

Flexor - decreases joint angle
Extensor - increases joint angle
Abductor - moves bone away from midline
Adductor - moves bone closer to midline
Levator - raises or elevates body part
Depressor - lowers or depresses a body part
Supinator - turns palms anteriorly
Pronator - turns palms posteriorly
Sphincter - decreases the size of the opening
Tensor - makes a body part rigid
Rotator - rotates bone around longitudinal axis

Question 10

Define the common terms used in muscle names that describe number of origins.

Answer 10

Biceps - two origins
Triceps - three origins
Quadriceps - four origins

Question 11

Give an example term used in muscle names that describe location.

Answer 11

Example: temporalis - muscle near temporal bone

Question 12

Give an example terms used in muscle names that describe origin and insertion.

Answer 12

Example: sternocleidomastoid - originating on sternum and clavicle and inserting on mastoid process of temporal bone