Muscles

Question 1

Striated or Skeletal Muscle

Answer 1

Also called Voluntary Muscle

type of muscle that makes up most of the structures that are responsible for speech production

Question 2

characteristics of voluntary muscle

Answer 2

under direct control - you can move it freely

Found in the muscles of the articulation and chewing or mastication

Question 3

Characteristics of Striated or Skeletal Muscle

Answer 3

1. Voluntary
2. contracts rapidly, but tires easily
3. responsible for body motility or movement
4. varies greatly in size

Question 4

What is muscle architecture?

Answer 4

refers to the way that muscles may be described by their appearance

Question 5

Types of muscle architecture

Answer 5

PRP
1. Parallel - spindle-shaped muscle that has a good range of motion and endurance. e.g. bicep muscles

2. Radiating - a fan-shaped muscle (found in cranium around the temporal lobe)
3. Pennate - AKA penniform. muscle resembles a feather. good force, less range of motion. e.g. pectoral muscles

Question 6

What are the points of attachments for muscles?

Answer 6

two points -1. stabilization 2. movement

1. ORIGIN: proximal end of the muscle. no movement. will STABILIZE or fix the muscle
2. INSERTION: distal end of muscle. This one will give movement

Question 7

Muscle Contraction

Answer 7

When a muscle contracts, the distance between the origin and the insertion of the muscle will shorten or decrease

This is what allows a structure to move

Question 8

The insertion point tells you what?

Answer 8

what structure will be allowed to move when the muscle contracts

e.g. when biceps contract, arm bends

e.g. Zygomatic major (facial muscle responsible for raising corners of mouth for smile/laughs)

Origin: zygomatic bone (cheek bone)
Insertion: angle of the mouth
Function: produces a broad smile with contraction of the zygomatic major

Question 9

Origin and Insertion Examples: Posterior Cricoarytenoid (PCA)

Answer 9

Origin: posterior (back) aspect of cricoid cartilage

Insertion: Muscular process (elevation) of the arytenoid cartilage

Function: will abduct or open the vocal folds

Question 10

Origin and Insertion Examples: Masseter (muscle in mastication)

Answer 10

Origin: Maxillary process (elevation/projection) of zyygomatic bone

Insertion: Mandible

Function: Elevate or close the jaw. Important for mastication/chewing

Question 11

What does NOMENCLATURE mean?

Answer 11

Name

Refer to the way in which muscles are named according to their

1. Shape (geometric names)
2. Location in the body
3. Function

Question 12

Geometric Names

Answer 12

Reflect SHAPE

e.g. quadratus (quad or rectangular shape)

e.g. Deltoid - means triangular

Question 13

General Form

Answer 13

Refers to APPEARANCE

e.g. serratus - saw like (serratus anterior around ribs)

Question 14

Location in the Body

Answer 14

Refers to LOCATION of muscle

e.g. temporalis (at the temporal bone of the cranium)

Question 15

Descriptive terms of the muscles

Answer 15

Usually paired muscles

Include:

Major
Minor
External
Internal

e.g. pec muscles - pectoralis major/minor

Rib Muscles
external intercostal
internal intercostal

Question 16

Number of Heads

Answer 16

Points of connection at the origin of a muscle

e.g. Biceps (2) + Triceps (3)

Question 17

Muscle Function

Answer 17

describes function of muscle aka what it does when it contracts

e.g. Tensor Tympani tenses the middle ear

Question 18

Structure of Skeletal Muscle

Answer 18

muscle consists of many muscle fibers, as well as other types of connective tissue (epimysium)

Question 19

Epimysium

Answer 19

Coarse, fibrous tissue that forms the outermost covering of a muscle

Question 20

Muscle cells or muscle fibers

Answer 20

The smallest unit of skeletal muscle tissue

Make up skeletal muscle

Surround by a covering called PERIMYSIUM

Question 21

Perimysium

Answer 21

Surrounds the cluster of muscle cells of skeletal muscle tissue

Question 22

Muscle Cells/fibers are Made up of?

Answer 22

MYOFIBRILS - densely packed + surrounded by

SARCOPLASM that contain

MYOGLOBIN (gives muscle reddish color)

Question 23

Myofibrils

Answer 23

Make up most of the muscle volume

Contain SARCOMERES - Basic units of all myofibrils

Question 24

sarcomeres (sarco = flesh; mere = piece - a piece of the muscle)

Answer 24

smallest contractile unit of muscle (functional unit of the muscle)

many sarcomeres link together in order to form a muscle

Question 25

What are the two proteins found in sarcomere?

Answer 25

MA

Myosin + Actin

Light or I Bands (isotropic) house Actin Filaments (AKA thin filaments)

Dark or A Bands (anisotropic) house Myosin Filaments (AKA Thick Filaments)

Question 26

Endomysium

Answer 26

connective tissue that surrounds the individual muscle fibers

Question 27

Contraction

Answer 27

SHORTENS the distance between the origin and insertion of a muscle

When a muscle contracts, it shortens (e.g. bending of arm as bicep contracts)

Question 28

Muscle Contraction Theory and where it begins

Answer 28

Cross Bridge Theory of Muscle Contraction or Sliding Filament Theory

All muscle contractions begin in the brain. The brain generates the initial signal that tells the muscle to contract

Question 29

How Muscle Contraction Occurs

Answer 29

1. Start is called Action Potential (AP). Begins in brain when brain sends the signal that tells the muscle to contract
2. AP travels down nerves to muscles
3. When it reaches the sarcomere, a chemical reaction causes “Cross Bridges” to form between the actin and myosin (thin + thick proteins)
4. Cross Bridge Formation refers to the LINKING of the Light/I Bands to the Dark/A Bands
5. As the Light/I Bands join with Dark/A Bands, they shorten the sarcomere
6. When sarcomeres get shorter, the myofibril shortens
7. When myofibril shortens, the muscle fibers shorten
8. When muscle fibers shorten, the muscle shortens (contracts)

Question 30

Length- Tension Relationship

Answer 30

the amount of force a muscle can produce at different lengths

Question 31

When does muscle generate its greatest force?

Answer 31

when it is at its resting length

Question 32

The amount of force a muscle can produce at different lengths

Answer 32

Length - Tension Relationship

Question 33

What are the 2 types of muscle contraction

Answer 33

1. Isometric - muscle generates force but does not produce movement

e.g. holding onto a bag of groceries

2. Isotonic - length of the muscle changes + movement occurs

Muscles will shorten with isotonic contraction. When muscles shorten, it will contract and movement will occur.

e.g. running, weightlifting, picking up a pencil.

Question 34

Muscle Tone

Answer 34

residual or background muscle tension or tonus of a muscle that is always present to some degree

constant, partial contraction of muscle tissue that helps you maintain posture + balance

Question 35

Why is muscle tone important?

Answer 35

maintenance of posture and balance

important in controlling the function of other organ systems

refers to overall stiffness of a muscle

Question 36

How is muscle tone regulated and what happens in sleep?

Answer 36

Regulated by several structures + neural pathways in brain

decreased during sleep, coma, and unconsciousness

Question 37

Hypotonicity

Answer 37

Lack of muscle tone or diminished muscle tone

Can range from mild to severe - adversely affect speech production, walking, chewing, eating

Clinical dx: Might be present in patients with CP, Muscular Dystrophy, stroke

Question 38

Hypertonicity

Answer 38

too much muscle tone. Increased or rigid muscle tone. also affect speech production, chewing, walking etc.

Clinical dx where it is present: CP, PD, stroke