Overview
This lecture covers key terminology of the muscular system, focusing on types of muscles, common roots and prefixes, naming conventions, types of contractions, and clinical terms relevant to muscle function.
Types of Muscle Tissue
- Skeletal muscle is attached to bone and responsible for voluntary movement.
- Smooth muscle (visceral muscle) controls involuntary movements in organs and vessels.
- Cardiac muscle is found in the heart and operates involuntarily.
Key Roots, Prefixes, and Suffixes
- My/o- refers to muscle (e.g., myalgia: muscle pain, myopathy: muscle disease).
- Myocarditis means inflammation of heart muscle (myo-: muscle, card-: heart, -itis: inflammation).
- Leiomy/o- refers to smooth muscle (e.g., leiomyoma: tumor of smooth muscle).
- Rhabdomy/o- refers to skeletal (striated) muscle (e.g., rhabdomyosarcoma: malignant tumor).
- Muscul/o- is Latin for muscle (e.g., musculocutaneous: relating to muscle and skin).
- Tend/o- or tendin/o- relates to tendons (e.g., tendinitis: tendon inflammation).
- Fasci/o- pertains to fascia, connective tissue of muscles (e.g., fasciodesis: fascia attachment surgery).
Muscle Naming Criteria
- Shape: e.g., trapezius (diamond-shaped), deltoid (triangular), serratus (saw-like).
- Size: e.g., gluteus maximus (largest), vastus lateralis, adductor longus.
- Fiber orientation: e.g., transverse (perpendicular), oblique (angled), rectus (parallel).
- Action: e.g., flexor digiti minimi (flexes little finger), extensor hallucis brevis (extends big toe).
- Number of heads: e.g., biceps (two heads), triceps (three), quadriceps (four).
- Attachments: e.g., sternohyoid (sternum and hyoid), pubococcygeus (pubic to coccygeal bones).
- Location: e.g., temporalis (temporal region), intercostal (between ribs), superficialis/profundus (surface/deep).
Muscle Function and Contraction Types
- Agonist (prime mover): main muscle causing movement (e.g., biceps brachii for elbow flexion).
- Synergist: assists agonist or stabilizes joint.
- Antagonist: opposes agonist, controls movement (e.g., triceps brachii for elbow extension).
- Isotonic contraction: muscle changes length (includes concentric: shortening, and eccentric: lengthening with tension).
- Isometric contraction: muscle exerts force without changing length (e.g., holding a plank).
Clinical and Functional Terms
- Spasmo- relates to involuntary muscle contractions (e.g., spasmogenic: causing spasm).
- -trophy means growth or development (e.g., atrophy: wasting, hypertrophy: overgrowth).
- Clonic refers to alternating contraction and relaxation (from clonus).
Key Terms & Definitions
- Skeletal muscle — voluntary muscle attached to bones
- Smooth muscle — involuntary muscle in organs and vessels
- Cardiac muscle — involuntary muscle found in the heart
- Myalgia — muscle pain
- Myopathy — muscle disease
- Tendinitis — inflammation of a tendon
- Fascia — connective tissue covering muscles
- Isotonic contraction — contraction with muscle length change
- Isometric contraction — contraction without muscle length change
- Agonist — prime mover muscle
- Antagonist — muscle opposing the prime mover
- Atrophy — decrease in muscle size
- Hypertrophy — increase in muscle size
- Clonic — rapid alternating muscle contractions and relaxations
Action Items / Next Steps
- Practice breaking down muscle terminology into roots, prefixes, and suffixes.
- Attempt the given challenge: define provided muscular terms using lecture material.
- Review upcoming cardiovascular terminology in the next episode.