Intro To Muscles And Directional Terminology

Question 1

Name the components of skeletal muscles from smallest to largest

Answer 1

Myofibril -> Muscle fibre -> Fascicle -> Skeletal muscle

Question 2

Describe myofibril

Answer 2

-Smallest unit of muscle
-Thread-like structures with contractile function
-Made up of thick and thin filaments called actin and myosin

Question 3

Describe muscle fibre/myofibre/muscle cell

Answer 3

A group of myofibrils encased in a fascial sleeve called the endomysium

Question 4

Describe fascicle

Answer 4

A group of muscle fibres encased in a fascial sleeve called the perimysium

Question 5

Describe skeletal muscle

Answer 5

A group of fascicles encased in a common fascial sleeve called the epimysium

Question 6

Name the 3 types of muscle tissue

Answer 6

Skeletal, cardiac, smooth

Question 7

Describe skeletal muscle tissue

Answer 7

-Primarily move bones
-Striated-alternating light and dark bands due to thick and thin filaments
-Primarily under voluntary control
-Can become involuntary (diaphragm, postural muscles, and resting tone)
-Fibre direction typically parallel to direction of muscle pull

Question 8

Describe cardiac muscle tissue

Answer 8

-Striated-alternating light and dark bands under a microscope
-Involuntary control
-Has intercalated discs which allow communication between neighbouring cardiac myocytes

Question 9

Describe smooth muscle tissue

Answer 9

-Non-striated
-Involuntary control
-Present in gastrointestinal tract around hollow organs
-Around blood vessels, airways, hair follicles

Question 10

Describe fascia

Answer 10

Fibrous membrane covering, supporting and separating muscle tissue

Question 11

Describe aponeurosis

Answer 11

Sheet-like tendon joining one muscle with another, or a muscle with a bone

Question 12

Describe tendon

Answer 12

-White, fibrous cord of dense, regular connective tissue
-Attaches muscle to bone

Question 13

Outline the functions of muscle tissue

Answer 13

-Motion
-Maintain posture/stabilize
-Venous flow
-Thermogenesis
-Register volume of internal organs

Question 14

Name the various fibre arrangements

Answer 14

-Longitudinal
-Quadrate
-Triangular
-Circular
-Fusiform
-Penniform (unipennate, bipennate, and multipennate)

Question 15

Describe longitudinal fibres and give examples

Answer 15

Long, strap-like fibres running parallel to longitudinal axis
Ex. rectus abdominus, sartorius

Question 16

Describe quadrate fibres and give examples

Answer 16

Flat, four sided muscles with fibres that run parallel to line of pull
Ex. rhomboids, pronator quadratus

Question 17

Describe triangular fibres and give examples

Answer 17

-Flat, fan-shaped muscles
-Fibres radiate from a narrow attachment to a broad attachment or vice-a-versa
Ex. pectoralis major and minor

Question 18

Describe circular fibres and give examples

Answer 18

Circular, typically sphincter muscles that surround an opening
Ex. orbicularis oris, orbicularis occuli

Question 19

Describe fusiform fibres and give examples

Answer 19

Round, spindle-shaped, tapered at both ends
Ex. brachialis, brachioradialis

Question 20

Describe penniform fibres and give examples

Answer 20

-Unipennate: Short parallel fibres originating from one side of a tendon
Ex. extensor digitorum longus, tibialis posterior
-Bipennate: Double pennate fibres on both sides of a central tendon, like a feather
Ex. rectus fermoris, flexor hallucis longus

Question 21

Describe multipennate fibres and give examples

Answer 21

Several tendons with muscle fibres running diagonally between
Ex. deltoid, serratus posterior superior

Question 22

Describe origin and insertion

Answer 22

-Origin: generally refers to the proximal attachment or stationary bone
-Insertion: generally refers to the distal attachment or moving bone

Question 23

Describe prime mover, synergist, and antagonist

Answer 23

-Prime Mover: the muscle directly responsible for producing a desired motion
-Synergist: a muscle that assists the prime mover
-Antagonist: a muscle that has the opposite action to the prime mover

Question 24

Name muscular terms for direction

Answer 24

-Rectus: implies parallel to midline
-Transverse
-Oblique

Question 25

Name muscular terms for size

Answer 25

-Maximus
-Minimus
-Longus
-Brevis

Question 26

Name muscular terms for shape

Answer 26

-Serratus
-Quadratus

Question 27

Name muscular terms for action

Answer 27

-Flexor
-Adductor
-Levator
-Pronator
-Rotatores

Question 28

Name muscular terms for no. of origins

Answer 28

-Bi
-Tri
-Quad

Question 29

Name muscular terms for location

Answer 29

-Temporalis
-Lateral
-Medial
-Superior
-Inferior

Question 30

Describe inferior/caudal and superior/rostral/cephalad

Answer 30

-Inferior/caudal: toward feet
-Superior/rostral/cephalad : toward the head

Question 31

Describe ipsilateral and contralateral

Answer 31

-Ipsilateral: to same side
-Contralateral: to opposite side

Question 32

Describe midsagittal, parasagittal, oblique

Answer 32

-Midsagittal: vertical, divides body into equal left and right halves down the midline
-Parasagittal: vertical, divides body into unequal left and right halves
-Oblique: plane passes through the body or organ at an angle between two planes

Question 33

Describe superior and inferior rotation of the scapula

Answer 33

-Superior rotation: glenoid fossa faces superiorly
-Inferior rotation: glenoid fossa faces inferiorly

Question 34

Describe medial (internal) and lateral (external) rotation of the scapula

Answer 34

-Medial rotation: medial border lifts from thorax, occurs with protraction
-Lateral rotation: medial border returns to thorax, occurs with retraction

Question 35

Describe elevation and depression of the scapula

Answer 35

-Elevation: humeral head moves superior
-Depression: humeral head moves inferior

Question 36

Describe the positions of the whole body

Answer 36

-Supine: on back
-Prone: on front
-Lateral recumbent: on side, sidelying
-Semi-fowlers position/semi-supine: partially supine