BSC Lab 6 - Unit 10

Muscle Tissues and Physiology

Epimysium

outermost layer, binds to tendons

Perimysium

surrounds fascicles

Fascicles

groups of muscle fibers, functional unit

Endomysium

surrounds individual muscle fibers (sarcomeres)

Skeletal Muscle

• voluntary

• long cylindrical fibers

• striated

• multiple nuclei

• MOVEMENT* 

Cardiac Muscle

• involuntary

• branched, short fibers

• intercalated discs

• single nuclei 

• BEATING OF HEART*

Smooth Muscle

• involuntary

• thin cells

• gap junctions

• single nuclei 

• SHAPE OF ORGANS*

Outer covering of muscle

endomysium

nucleus

mitochondria

myofibrils

• roadlike structure

• parallel to muscle fibers

myofilaments

sarcolemma

transverse (T) tubules

sarcoplasmic reticulum

Sarcolemma

muscle’s plasma membrane

Sarcoplasm

muscle’s cytoplasm

Sarcomere

smallest functional unit

Blue fibers?

thin filament (actin)

Red fibers?

thick filament (myosin)

Zigzag lines?

Z disc

Dashed lines?

H zone

What is muscle contraction caused by?

1. ACh triggers potential

2. Action potential in sarcolemma travels down t-tubes, triggers Ca+ releases from SR into cytosol

3. Ca2+ bind to troponin, moves tropomyosin away

4. Actin and myosin bond, ATP detaches actin and myosin

5. Repeats until ACh is no longer released

Generation period of gradient

Latent period

Steep rise, actins are contracting

Contraction period

Tension decreases, Ca ions are pumped back

Relaxation period

Origin

attachment at stationary end of muscle

Insertion

attachment to mobile end of muscle 

Location of attachments

origin and insertion

Muscle action

flexor, extensor, adductor, abductor

Location

bone or region

Shape

ex. deltoid, trapezius

Size

ex. maximus, longus, brevis

Direction of fibers/fasicles

ex. rectus, transversus, oblique

# of origins

ex. biceps, triceps, quadriceps

About how many muscles are in the human body?

700

pectorals (pecs)

rectus abdominus (abs)

obliques

erector spinae

frontalis

orbicularis oculi

orbicularis oris

zygomatic minor

zygomatic major

**72 

buccinator

occipitalis

masseter

temporalis

sternocleidomastoid

splenius capitis

Erector Spinae Group

1. Spinalis

2. Longissimus

3. Illiocostalis

Spinalis thoracis

Longissimus thoracis

Iliocostalis

Diaphragm

external intercostal muscles

internal intercostal muscles 

rectus abdominis

external oblique

internal oblique

transverse abdominis

linea alba

Serratus anterior

trapezius

pectoralis major

latissimus dorsi

deltoid

teres major

supraspinatus

infraspinatus

teres minor

subscapularis

What 3 muscles make up the rotator cuff?

1. supraspinatus

2. infraspinatus

3. teres minor

Biceps brachii

brachialis

brachioradialis

tripceps brachii

Flexor carpi ulnaris

flexor carpi radialis

tensor fascia lata

vastus lateralis (quad)

vastus medaialis (quad)

vastus intermedius (quad)

rectus femoris

gluteus maximus

biceps femoris (hamstring)

**33

soleus