Muscle Tissue - Anat

Front 1

Where does muscular tissues arise from

Back 1

mesoderm

Front 2

Two major groups

Back 2

1. Striated - found as skeletal muscle and cardiac muscle
2. Smooth - found in the wall of hollow viscera, blood vessels, and dermis of skin

Front 3

Parts of a Muscle Cell (Fiber

Back 3

Sarcolema - cell membrane
sarcoplasm - cytoplasm
sarcoplasmic reticulum - ER
sarcosome - mitochondria
myofilament - microfilament
myoglobin - pigment

Front 4

What are skeletal muscles composed of?

Back 4

Long cylindrical, multinucleated cells

Front 5

What are muscle fibers individually surrounded by?

Back 5

A layer of CT called endomysium

Front 6

What do lots of muscle fibers form?

Back 6

A muscle bundle

Front 7

What are muscle bundles surrounded by?

Back 7

A layer of CT called perimysium

Front 8

What do lots of muscle bundles form?

Back 8

A muscle

Front 9

What is the whole muscle wrapped by?

Back 9

A third layer of CT called epimysium

Front 10

Within each muscle fiber, there are bundles (myofibril) of what?

Back 10

Myofilaments

Front 11

What is each myofibril surrounded by what?

Back 11

An interconnected network of ER (sarcoplasmic reticulum)

Front 12

Among these myofibrils, numerous what are found?

Back 12

Numerous mitochondria (sarcosomes)

Front 13

Myofibrils show what types of striations

Back 13

light (I) and dark (A) bands

Front 14

How many types of myofilaments are there and what are they?

Back 14

Two:
1. Thick (myosin) made up of myosin molecules with heavy and light subunits
2. Thin (actin) made up of troponin and tropomyosin

Front 15

What are thick and thin filaments attached to?

Back 15

actin, directly and myosin, indrectly to "Z" disks

Front 16

What is the A band?

Back 16

Part of the myofibril which is occupied by BOTH types of myofilaments

Front 17

What is the I band?

Back 17

Part of the myofibril which contains only the THIN filaments

Front 18

What is the H band?

Back 18

Part of the myofibril which contains only the THICK filaments

Front 19

What happens to the myofibril during muscle contraction?

Back 19

Width of I and H bands reduce leading to the shortening of sarcomeres

Front 20

Where are sarcomeres found?

Back 20

Between two Z bands

Front 21

What are terminal cisternae

Back 21

The two ends of reticular network surrounding the myofibrils

Front 22

What are two adjacent cisternae separated by?

Back 22

A transverse tubule (continuous with the sarcolemma)

Front 23

What is a triad?

Back 23

Two adjacent terminal cisternae separated by a transverse tubule

Front 24

Describe the Sliding Filament Theory (6 steps)

Back 24

1. An impulse is transmitted to the interior of the fiber via transverse tubule
2. Ca++ leave the terminal cisterna and enter the cytosole
3. Conformational changes in troponin in the presence of Ca++ causes the tropomyosin to sink down, exposing the active site of actin
4. Hydrolysis of ATP to ADP and a phosphate group at the presence of Mg++
5. Formation of a strong bond between actin and myosin while the myosin molecule bends
6. Another ATP binds to the myosin, leading to its detachment from actin

Front 25

Skeletal Muscle Fiber Types (3)

Back 25

1. Red (Type I) - aerobic, slow twitch with high endurance. Contain numerous mito and myoglobin (postural muscles)
2. White (type IIB), anaerobic, fast twitch, and capable producing high force. Contain few mito
3. Intermediate (type IIA) - pinkish

Front 26

Appearance of smooth muscle?

Back 26

Fusiform (spindle shaped) with a centered mono-nucleus with NO striation
-acidophilic cytoplasm

Front 27

Do smooth muscle cells have the T tubule system?

Back 27

No

Front 28

What is each smooth muscle cell surrounded by?

Back 28

A thin layer of CT (external lamina)

Front 29

Most important function of smooth muscle is?

Back 29

Peristaltic movements of GI tract and constriction of blood vessels

Front 30

Describe smooth muscle contraction

Back 30

Slower, more energy efficient, more sustainable, and shows less fatigue compared to skeletal muscle tissue

Front 31

Three myofilaments of smooth muscle are?

Back 31

Thick (myosin), thin (actin), and intermediate (desmin / vimentin)

Front 32

How are smooth muscle filaments attached to each other?

Back 32

They are attached to each other inside the cytoplasm and also to the cell membrane by means of dense bodies (Z band equivalent)