1. Produce body movements

2. Stabilize body positions

3. Regulate organ volumes-bands of smooth muscle called sphincters

4. Movement of substances within the body-blood, lymph, urine, air, food/fluids, sperm

5. Produce heat-involuntary contractions of skeletal muscle (shivering)

1. Skeletal

2. Cardiac

3. Smooth

1. Excitability

2. Contractility

3. Extensibility

4. Elasticity

The ability to respond to stimulation:

-Skeletal muscles normally respond to stimulation by the nervous system.

-Cardiac and smooth muscles respond to the nervous system and the endocrine system (circulating hormones)

1. Spindle-shaped cells with one centrally located nucleus

2. Cytoplasm looks smooth-no striations; microfilaments spiral down the cell like a barber shop pole

3. Cells form into sheets in walls of organs and vessels

4. Have the ability to regenerate

5. Help push solids/fluids along digestive tract

1. Branching cells/fibers

2. One or two centrally located nuclei per cell

3. Contain myofibrils that are regularly arranged (striated), but are difficult to distinguish because of irregular branching cells with varying width-->irregularity due to a larger number of mitochondria

4. Cells held together by intercalated discs

5. No regeneration

1. Contractile organs directly or indirectly attached to bones of the skeleton

2. Striations formed by myofibril arrangements

3. Have the ability to regenerate

1. Produce skeletal movement

2. Maintain posture and body position

3. Support soft tissues

4. Regulate entering and exiting of material

5. Maintain body temperature

1. Specific body regions

2. Shape of the muscle

3. Orientation of muscle fibers

4. Specific or unusual features

5. Identification of origin and insertion

6. Primary functions

7. References to actions

1. Endomysium

2. Perimysium

3. Epimysium

CT surrounds fascicles

-attachment site for nerve and blood vessels

CT surroinds the entire muscle

-attachment site for nerves and blood vessels

Aponeurosis

-Formed by combining of Endomysium, perimysium, and epimysium

-All myofibrils are arranged parallel to the long axis of the cell with sarcomeres laying side by side

-Myosin (thick) and actin (thin) filaments are arranged within a myofibril and organized in sarcomeres (z line to z line)

Size of thick and thin filaments

(exact and relative)

Thick: 10-12 nm diameter, 1.6 micrometer length

--Larger than thin filaments

Thin: twisted interacting proteins 5-6 nm diameter, 1 micrometer length

--smaller than thick filaments

Naming of muscle fibers

(Muscle fiber organization)

1. Parallel

2. Convergent

3. Unipennate

4. Bipennate

5. Multipennate

6. Circular

Parallel muscle fiber organization

example

fibers run parallel to the long axis of the muscle

biceps brachii

Convergent muscle fiber organization

example

Muscle fibers converge from a wide area to a small area

Pectoralis major

Unipennate muscle fiber organization

example

Muscle fiber at an angle on one side of the tendon

Extensor digitorum

Bipennate muscle fiber organization

example

Muscle fibers at an angle on both sides of the tendon

Rectus femorus

Multipennate muscle fiber organization

example

Muscle fibers converge from a wide area to a small area.  The tendo branches within the muscle

Deltoid

Circular muscle fiber organization

example

Muscle fibers concentrically arranged around an opening

eye, mouth

Muscle origin

(part of OIAs)

Muscle insertion

(part of OIAs)

1. If the muscle extends from a broad aponeurosis to a narrow tendon (frontalis), aponeurosis =origin; tendon=insertion

2. If there are several tendons at one end and only one at the other (pectoralis major), multiple tendon end=origin; single tendon end=insertion

Muscle action

(part of OIAs)

1. Reference the bone region affected

(flexion of the forearm)

2. Specifies the joint involved

(felxion of the elbow)

1. Prime movers

2. Synergists

3. Antagonists

1. Nerve impulse reaches an axon terminal and synaptic vesicles release acetylcholine (ACh)

2. ACh diffuses to receptors on the sarcolemma and Na+ channels open--Na+ rushes into the cell

3. A muscle action potential spreads over the sarcolemma and down into the T-tubes

4. Sarcoplasmic reticulum releases Ca ions into the sarcoplasm

5. Ca ions bind to troponin and causes troponin-tropomyosin complex to move and reveal myosin binding sites on actin--->the contraction cycle begins

Muscle Tone

continuous contraction that produces a resting tension in skeletal muscle

-stabilizes the position of bones and joints

Exercise causes an increase in

-number of mitochondria

-Glycogen reserves

-Myofibrils

*Causes enlargement of the stimulated muscle

-Large in diameter because of many densely packed myofibrils

-Large glycogen reserves

-Relatively few mitochondria (mitochondria are unable to meet the demand)

-Fatigue easily

-Can contract in .01 sec or less followinf stimulation

-Anaerobic movements for short duration

(dominant in weight lifters and sprinters)

1. Fast fibers

2. Slow fibers

-half the diameter of fast fibers

-take 3 times as long to contract after stimulation

-contain abundant mitochondria

-use aerobic metabolism

-have more extensive network of capillaries that muscles dominated by fast muscle fibers

-are red due to pigment called myoglobin

-Prolonged, sustained contractions for maintaining posture

(dominant in marathon runners)

-Skeletal muscle fibers become smaller in diameter

-Skeletal muscles become less elastic

-Tolerance for exercise decreases

-ability to recover from injury decreases

-State of muscular rigidity that begins 3-4 hours after death and lasts about 24 hours

-After death, Ca2+ ions leak out of the sarcoplasmic reticulum and allow myosin heads to bind to actin

-Since ATP synthesis has ceased, crossbridges cannot detach from actin until enzymes begin to digest decomposing cells

Muscular Distrophy

What is it?

What is occuring?

What is affected?

MD

-Group of rare inherited muscle diseases in which muscle fibers are unusually susceptible to damage

-Primarily voluntary muscles become weaker

-In the later stages, fat and connective tissue often replace muscle fibers

-In some types of MD, heart and other involuntary muscles are affected

Cure for MD

Therapy

No cure

-Respiratory therapy

-Physical therapy

-Steroids and corrective orthopedic surgery may be needed

-Cardiac abnormalities may require a pacemaker

Sliding filament theory

Location of action

1. Acetylcholine (ACh) is realeased by the motorneuron and passed to the sarcolemma.

2. ACh spreads over the entire sarcolemma

3. Na+ ions are spread through the cell via T-tubes as a result of the ACh

4. T-tubes spread the action potential through the cell

5. This causes the sarcoplasmic reticulum to open Ca channels initiating a muscle contraction

6. The released Ca2+ ions bind with proteins (troponin-tropomyosin complex) on actin, which causes the protein complex to expose a myosin binding site on actin

7. The myosin heads (crossbridges) have an ATP molecule that has low affinity for actin

8. ATP is split into ADP and an inorganic phosphate (usable form of energy)

9. The myosin heads cock allowing them to bind with the exposed binding site on actin

10. The loss of the inorganic phosphate causes the myosin heads to swivel from 90 deg to 45 deg, moving the attached actin

11. The movement brings the Z-lines together, shortening the sarcomere, resulting in the contraction

12. The contraction continues while ATP and Ca+ are still available in the cell.  A max contraction occurs when myosin butts from Z-line to Z-line 

Sliding filament theory

Ending a contraction

Electrical stimulation ends

-Sarcoplasmic reticulum recaptures the Ca2+ ions

-Troponin-tropomyosin complex cover the active sites

-contraction ends

1. acetylcholinesterase breaks down ACh within the synaptic cleft

2. Muscle action potential ceases

3. Ca2+ ion channels close

4. Active transport pumps Ca ions back into storage in the sarcoplasmic reticulum

5. Ca binding protein (calsequestrin) helps hold Ca ions in SR

6. Troponin-tropomyosin complex recovers binding site on the actin

O: Mandible and maxillae

I: Orbicularis Oris

A: Blowing, compress cheek

O: Zygomatic arch and maxillae

I: Coronoid process, ramus of mandible

A: Elevation of mandible, chewing

O: Zygomatic bone

I: Angle of mouth (obicularis oris)

A: Smiling

O: Clavicle and sternum

I: Mastoid process, superior nuchal line

A: tilt and rotate head, flex neck

O: Pubis

I: Costal cartilage, ribs 5-7, xiphoid process

A: Flex back

O: Superior nuchal line, spinous process C7-T12

I: Acromion process of clavicle, spine of scapula

A: rotation, retraction, elevation and depression of scapula

O: Short head: coracoid process of the scapula

Long head: glenoid cavity

I: Radial tuberosity

A: Flex elbow, supinate forearm

O: Lateral epicondyle of humerus

I: Middle and distal phalanges

A: Extend wrist, hand, fingers

O: Anterior superior iliac spine

I: Tibia (Anterior and medial side)

A: Flex knee and hip

O: Anterior inferior iliac spine

I: Patella (tendon)

A: Extend knee, flex hip

O: Lateral and medial condyles of femur

I: Calcaneous

A: Plantarflexion

1. Muscles of the head and neck

2. Muscles of the vertebral column

3. Oblique and rectus muscles

4. Muscles of the pelvic floor

1. Muscles of facial expression

2. Muscles of the eye

3. Muscles of mastication

4. Muscles of the neck

5. Muscles of the tongue

6. Muscles of the pharynx

1. Superficial: move the neck

2. Intermediate: extend the vertebral column

3. Deep: interconnect vertebrae