Lab 6 Intro Slides - Muscle Tissue and Axial Muscles - F24

LAB 6: MUSCLE TISSUE AND AXIAL MUSCLES

Learning Objectives

  • Identify and Describe Muscle Tissues: Understand the characteristics and functions of the three types of muscle tissue.

  • Histological Differences: Differentiate between cardiac, smooth, and skeletal muscle tissue histologically.

  • Muscle Locations: Be aware of where each type of muscle tissue is found in the body.

  • Muscle Identification: Know the major muscles including their origins and insertions.

  • Actions of Muscles: State the actions associated with assigned muscles.

Types of Muscle Tissue

  • Cardiac Muscle

    • Characteristics: Involuntary, striated, single nucleus.

    • Location: Found in the heart.

    • Microscopic Features:

      • Intercalated discs.

      • Branching fibers.

  • Smooth Muscle

    • Characteristics: Involuntary, non-striated, single nucleus.

    • Location: Walls of hollow organs (e.g., intestines, blood vessels).

    • Microscopic Features:

      • Spiral nuclei and smooth muscle fibers.

      • Inner circular and outer longitudinal layers.

  • Skeletal Muscle

    • Characteristics: Voluntary, striated, multinucleate.

    • Location: Attached to bones.

    • Microscopic Features:

      • A bands (dark regions) and I bands (light regions).

      • Presence of multiple nuclei along muscle fibers.

Architecture of Skeletal Muscles

  • Shapes of Skeletal Muscles:

    • Circular Muscles: Fibers form a continuous circle (e.g., sphincters).

    • Convergent Muscles: Broad at origin, converges to a thin insertion (e.g., pectoralis major).

    • Parallel Muscles: Fibers are parallel, muscle is long and thin (e.g., sartorius).

    • Pennate Muscles: Tendons attach to fibers; types include:

      • Unipennate

      • Bipennate

      • Multipennate

Naming of Skeletal Muscles

  • Conventions for Naming:

    • Based on Shape or Size (e.g., "rectus" means straight).

    • Based on Number of Heads/Bellies (e.g., "biceps" means two bellies).

    • Based on Position/Depth (e.g., "oris" refers to mouth).

    • Based on Action (e.g., "levator" means lifter).

Muscle Origins and Insertions

  • Definition of Origin and Insertion:

    • Origin: Less movable end of a muscle.

    • Insertion: More movable end of a muscle.

    • Example:

      • Biceps Brachii:

        • Origin: Scapula

        • Insertion: Radius

Muscles of the Head, Neck, and Face

  • Functions: Responsible for head movement, mastication, facial expressions, and speech.

  • Key Muscles:

    • Epicranius

    • Masseter

    • Buccinator

    • Sternocleidomastoid

    • Temporalis

    • Orbicularis Oculi

    • Zygomaticus Minor and Major

    • Orbicularis Oris

Muscles of the Trunk

  • Categories:

    • Muscles of the Vertebral Column

    • Muscles of Respiration

    • Muscles of the Abdominal Wall

Muscles of Respiration

  • Involved in breathing through pressure change in the thoracic cavity.

  • Key Muscles:

    • External Intercostals

    • Internal Intercostals

    • Diaphragm

Abdominal Wall Muscles

  • Layers of Abdominal Wall Muscles (Superficial to Deep):

    • External Obliques

    • Rectus Abdominis (Medial)

    • Internal Obliques (Lateral)

    • Transversus Abdominis

Muscles of the Back

  • Functions: Contribute to torso and vertebral column movement.

  • Key Muscles:

    • Trapezius

    • Latissimus Dorsi

    • Erector Spinae Groups (Iliocostalis, Longissimus, Spinalis)

Lab Practical Tasks

  • Identify Lab Structures: Find and identify muscles on models, including:

    • Muscle torso model

    • Muscle models (small and large)

    • Muscle arm and leg models

  • Microscope Work: View and identify cardiac, smooth, and skeletal muscle slides.

  • Complete Activities: Engage in check-off activities and fill out post-lab and pre-lab information for continuity in learning.