Extrinsic tongue muscle

1. Genioglossus
2. Chondroglossus
3. Hyoglossus
4. Styloglossus
5. All innervated by hypoglossal nerve.
   
   

External eye muscle

• Levator palpebrae superioris:

1. Forms levator aponeurosis
2. Inserts on superior tarsal plate and skin of upper eyelid
3. Oculomotor nerve

• Superior rectus: oculomotor nerve
• Superior oblique: trochlear nerve
• Medial rectus: oculomotor nerve
• Lateral rectus: abducens nerve
• Inferior rectus: oculomotor nerve
• Inferior oblique: oculomotor nerve

Two muscles of the middle ear

• Tensor tympani

1. Mandibular branch of trigeminal nerve
2. Reduce chewing sounds and loud noise

• Stapedius

1. Facial nerve
2. Reduce chewing sounds and loud noise

Differences among skeletal, cardiac, and smooth muscle

• Skeletal muscle:

1. Striated
2. Unbranched
3. Z line
4. Multinuclei, peripheral
5. T tubules forms triad at A-I junction
6. No gap junctions

• Cardiac muscle:

1. Striated
2. Branched
3. Z line
4. One nucleus, center
5. T tubules forms dyad at Z line
6. Intercalated discs, gap junctions

• Smooth muscle:

1. No striated
2. No Z line
3. Dense bodies
4. One nucleus
5. No T tubules
6. Gap junctions

Scaffolding proteins of skeletal muscles

1. Nebulin: along actin to Z line
2. Titin: along myosin to Z line

Two types of skeletal muscle

• Red skeletal muscle fibers:

1. Type I
2. high myoglobin & mitochondria content
3. aerobic
4. low ATPase
5. slow movement muscle, posture-maintainig muscle

• White skeletal muscle fibers:

1. Type II
2. low myoglobin & mitochondria content
3. anaerobic
4. high ATPase
5. fast movement muscle: eye muscles, hands, legs

Skeletal muscle

1. Sarcolemma (muscle cell membrane), endomysium (CT arround sarcolema), perimysium, epimysium
2. Multiple nuclei, peripheral
3. Limited ability to regenerate
4. Stem cells: satellite cells. Low satellite cell numbers in muscular dystrophy.