Course Overview

Test Two scheduled for April 9, approximately one month away. This course is an abbreviated version integrating key concepts from Human Anatomy I (BIO 130) and Human Anatomy II (BIO 132). The course provides foundational knowledge beneficial for subsequent biology courses (BIO 130 & 132).

Primary Tissue Types

Discussing the four primary tissue types in humans:

• Muscle: Tissue responsible for movement, allowing bodily functions through contraction and relaxation.

• Connective Tissue: Provides support, binds other tissues together, and stores energy.

• Nerve Tissue: Transmits impulses and processes information through neurons and glial cells.

• Epithelial Tissue: Covers body surfaces and lines cavities, functioning in protection, absorption, and secretion.

Muscle Overview

Muscles are critical for movement and functionality:

• Capable of changing shape (lengthening and shortening) to facilitate movement.

• Muscle contraction requires ATP, which is known as the energy currency of the cell and is produced in the mitochondria, often referred to as the "powerhouse" of the cell.

• Muscles also play a role in maintaining posture by continuously contracting to stabilize the body.

Types of Muscle Tissue

1. Skeletal Muscle

   • Attached to the skeleton, allowing for voluntary movements under conscious control.

   • Unique characteristic: multinucleated (each muscle fiber has multiple nuclei), enabling rapid repair and growth.

   • Example: Biceps muscle, crucial for flexing the arm.

2. Cardiac Muscle

   • Found exclusively in the heart, responsible for pumping blood throughout the body.

   • Involuntary, striated muscle composed of single nucleus myocytes that communicate via intercalated discs for synchronized contractions.

   • Features rhythmic contractions that are essential for maintaining heart rhythm.

3. Smooth Muscle

   • Composed of non-striated, spindle-shaped cells found in hollow organs such as the intestines, bladder, and blood vessels.

   • Involuntary, with a single nucleus per cell, enabling slow and sustained contractions for functions like peristalsis.

Muscle Anatomy and Function

• Each muscle has an origin (fixed point of attachment) and insertion (point pulled toward during contraction).

• Muscle contractions produce movement through the following anatomical planes:

  • Sagittal Plane: Divides the body into left and right.

    • Movements: Flexion (angle between joints decreases) and Extension (angle increases).

  • Coronal Plane: Divides the body into front and back.

    • Movements: Abduction (movement away from the midline) and Adduction (movement towards the midline).

  • Transverse Plane: Divides the body into top and bottom.

    • Movements: Rotation (turning about an axis, either medial or lateral).

Muscle Contraction Mechanism

• Myosin (thick filaments) and Actin (thin filaments) are key proteins involved in muscle contraction within the sarcomere:

  • The muscle fiber activation process involves calcium ions that trigger the binding of myosin heads to actin, leading to contraction.

  • The length of the muscle shortens as myosin pulls on actin during contraction, a process driven by the energy from ATP hydrolysis.

Role of Muscles in Body Function

• Muscles help maintain body temperature through contractions, releasing heat as a byproduct of metabolism.

• They assist in the movement of fluids in the body, such as blood through veins and lymph through lymphatic vessels.

• Muscles provide protection to internal organs, especially in regions where bony structures are absent, as seen in the abdominal area.

Key Concepts for Study

• Review definitions and identify key characteristics of each muscle type (skeletal, cardiac, smooth).

• Understand anatomical planes and movements associated with them, emphasizing how these concepts relate to physical activities.

• Know the role of ATP in muscle contraction and energy production, including the biochemical pathways involved (e.g., aerobic vs. anaerobic metabolism).

• Remember the significance of muscle attachments (origin, insertion) in producing movement, including how leverage plays a role in muscle efficiency during actions like lifting or running.