Anatomy & Physiology: Types of Muscles

Anatomy and Physiology Text Book Information

• Book title: Seeley's Essentials of Anatomy & Physiology
• Edition: Tenth Edition
• Authors: Cinnamon Vanputte, Jennifer Regan, Andrew Russo
• Publisher: McGraw-Hill Education
• Note: Separate PowerPoint slides are available for figures and tables, pre-inserted into PowerPoint presentations.

Types of Muscles

• Skeletal Muscle:
  • Attached to bones
  • Striated
  • Voluntarily controlled
• Cardiac Muscle:
  • Located in the heart
  • Striated
  • Involuntarily controlled
• Smooth Muscle:
  • Located in blood vessels and hollow organs
  • Non-striated
  • Involuntarily controlled

Comparison of Skeletal, Cardiac, and Smooth Muscles

• Body Location: Skeletal muscles are attached to bones or, sometimes, to skin. Cardiac muscles are located in the heart. Smooth muscles are found in walls of hollow organs.
• Cell Shape and Appearance: Skeletal muscle cells are long, cylindrical, and multinucleated, with obvious striations. Cardiac cells are branched and uninucleated and have striations and intercalated discs. Smooth muscle cells are single, fusiform (spindle-shaped), and uninucleated, without striations.
• Connective Tissue Components: Skeletal muscles have epimysium, perimysium, and endomysium. Cardiac muscles have endomysium. Smooth muscles have endomysium.
• Regulation of Contraction: Skeletal muscle contraction is voluntary and controlled by the nervous system. Cardiac muscles have a pacemaker and are controlled by the nervous system, the heart's own pacemaker, and hormonal input. Smooth muscle contraction is involuntary controlled by the nervous system and hormones.
• Speed of Contraction: Skeletal muscle contraction is slow to fast, cardiac is slow, and smooth is very slow.
• Rhythmic Contraction: Skeletal muscles do not contract rhythmically, cardiac muscles do, and smooth muscles can in some cases.

Skeletal Muscle Structure

• Skeletal muscle: Approximately 40% of body weight.
• Attachment: Skeletal muscles attach to the skeletal system, some to the skin or connective tissue sheets.
• Striations: Skeletal muscle is also called striated muscle.
• Connective Tissue Coverings:
  • Epimysium: Surrounds the entire muscle.
  • Perimysium: Surrounds fascicles (groups of muscle cells).
  • Endomysium: Surrounds individual muscle cells (fibers).

Muscle Fiber Structure

• Shape: Single cylindrical cells with multiple nuclei located at the periphery.
• Size: Ranges in length from 1 cm to 30 cm and are generally 0.15 mm in diameter.
• Sarcolemma: The cell membrane (sarcolemma) has transverse tubules (T-tubules) which are inward folds.
• Sarcoplasmic Reticulum: T-tubules are associated with enlarged portions of the smooth endoplasmic reticulum called terminal cisternae.
• Muscle Triad: T-tubules connect to the terminal cisternae to form a muscle triad.
• Sarcoplasm: The cytoplasm of a muscle fiber contains protein filaments called myofibrils.
• Myofibrils: Bundles of protein filaments (myofilaments).
• Myofilaments: Actin and myosin.

Muscles of the Head and Neck

• Facial Muscles
• Mastication Muscles: Muscles involved in chewing.
• Swallowing Muscles
• Eyes Muscles
• Head and Neck Muscles

Specific Facial Muscles

• Buccinator: Wall of the cheeks; flattens the cheek (as in whistling or blowing a trumpet);  "Kissing Muscle or Trumpeter's muscle"; compresses cheek to hold food teeth
• Depressor Anguli Oris: Lower corners of the mouth; depresses the corner of the mouth
• Levator Labii Superioris: Elevates one side of the upper lip
• OccipitoFrontalis: Moves scalp, raises eyebrows, and wrinkles forehead
• Orbicularis Oris: Closes the mouth and protrudes the lips; the "kissing" muscle
• Orbicularis Oculi: Closes the eyes, squints, blinks, and winks.
• Zygomaticus: The "smiling" muscle; elevates the upper lip and corner of the mouth

Chewing Muscles

• Masseter: Closes the jaw; elevates and pushes the mandible anteriorly
• Temporalis: Elevates and draws the mandible posteriorly
• Pterygoid:
  • Lateral: Pushes the mandible anteriorly and depresses the mandible, closes the jaw
  • Medial: Pushes the mandible anteriorly and elevates the mandible, closes the jaw

Tongue and Swallowing Muscles

• Tongue Muscles:
  • Intrinsic: Change the shape of the tongue
  • Extrinsic: Move the tongue
• Hyoid Muscles:
  • Suprahyoid: Elevates or stabilizes the hyoid bone.
  • Infrahyoid: Depresses or stabilizes the hyoid bone

Deep Neck Muscles

• Neck Flexors: Originate on the anterior side of the vertebrae, flex the head and neck.
• Neck Extensors: Originate on the posterior side of the vertebrae, extend the head and neck.

Specific Neck Muscles

• Sternocleidomastoid: Individually rotates the head; together it flexes the neck
• Platysma: Pulls the corners of the mouth inferiorly
• Trapezius: Extends and laterally flexes the neck

Trunk Muscles

• Vertebral Column
• Thorax
• Abdominal Wall
• Pelvic Floor

Specific Trunk Muscles

• Erector Spinae: Extends the vertebral column and maintains posture; divides into 3 columns: iliocostalis, longissimus, spinalis
• Deep Back Muscles: Located between spinous and transverse processes; responsible for movement of the vertebral column; extension, lateral flexion, rotation
• Thoracic Muscles:
  • Scalenes: Elevates ribs during inspiration
  • External Intercostals: Elevates ribs for inspiration
  • Internal Intercostals: Depresses ribs during forced expiration
  • Diaphragm: Moves during quiet breathing
• Abdominal Wall Muscles:
  • Rectus Abdominis: Center of the abdomen; compresses abdomen
  • External Abdominal Oblique: Sides of the abdomen; compresses abdomen
  • Internal Abdominal Oblique: Compresses abdomen
  • Transverse Abdominis: Compresses abdomen

Explore the different types of muscles in the human body through this quiz. Learn about skeletal, cardiac, and smooth muscles, including their characteristics, locations, and control mechanisms. Perfect for students studying Seeley's Essentials of Anatomy & Physiology.