Anatomy & Physiology: Tissues, Integumentary System, and Bone Tissue Study Guide

Chapter 4 – Tissues

Main Cells and Tissue Types

This section covers the fundamental cells involved in tissue formation and the classification of tissues in the human body.

• Blast Cells: These are immature cells responsible for building tissue, such as osteoblasts (bone-forming) and chondroblasts (cartilage-forming).

• Clast Cells: These are cells that break down tissue, such as osteoclasts (bone-resorbing).

• Cartilage Types: The three main types are hyaline cartilage (found in joints), elastic cartilage (found in the ear), and fibrocartilage (found in intervertebral discs).

• Epithelial Tissue: Classified by cell shape (squamous, cuboidal, columnar) and arrangement (simple, stratified). For example, simple squamous epithelium is found in alveoli of lungs.

• Glands: Epithelial tissue forms glands, which are classified as endocrine (secrete hormones into blood) or exocrine (secrete substances onto surfaces).

Example: Osteoblasts build bone matrix, while osteoclasts resorb bone during remodeling.

Chapter 5 – Integumentary System

Layers and Functions of the Epidermis

The integumentary system includes the skin and its derivatives. The epidermis consists of several layers, each with distinct characteristics and functions.

• Layers of the Epidermis: From superficial to deep: stratum corneum, stratum lucidum (only in thick skin), stratum granulosum, stratum spinosum, stratum basale.

• Characteristics: The stratum basale contains stem cells for regeneration; the stratum corneum provides a barrier.

• Functions: Protection, sensation, thermoregulation, and synthesis of vitamin D.

Vascularity of the Epidermis

• The epidermis is avascular; it receives nutrients via diffusion from the underlying dermis.

Skin Cancer Types

• Basal Cell Carcinoma: Originates in the stratum basale; most common and least dangerous.

• Squamous Cell Carcinoma: Arises from keratinocytes in the stratum spinosum.

• Melanoma: Develops from melanocytes; most dangerous due to high metastatic potential.

Types of Glands in the Skin

• Sudoriferous (Sweat) Glands: Eccrine (thermoregulation) and apocrine (odor, found in axillary/groin regions).

• Sebaceous Glands: Secrete sebum to lubricate skin and hair.

Matching Cells to Function

• Keratinocytes: Produce keratin for protection.

• Melanocytes: Produce melanin for UV protection.

• Langerhans Cells: Immune defense.

• Merkel Cells: Sensory receptors for touch.

Example: Eccrine glands help regulate body temperature by secreting sweat.

Chapter 6 – Bone Tissue

Organization of Bone Tissue

Bone tissue is organized into compact and spongy bone, each with unique structural and functional properties.

• Compact Bone: Dense, forms the outer layer; contains osteons (Haversian systems).

• Spongy Bone: Porous, found at ends of long bones; contains trabeculae.

Bone Cells and Their Roles

• Osteoblasts: Build bone matrix.

• Osteocytes: Mature bone cells maintaining bone tissue.

• Osteoclasts: Break down bone matrix.

Regulation of Bone Growth

• Hormones: Growth hormone, thyroid hormone, and sex hormones regulate bone growth and development.

• Epiphyseal Plate: Site of longitudinal bone growth; closes after puberty.

Importance and Function of the Epiphyseal Plate

• The epiphyseal plate (growth plate) is a layer of hyaline cartilage where new bone is produced during childhood and adolescence.

• Once growth is complete, the plate ossifies and becomes the epiphyseal line.

Example: Growth hormone stimulates chondrocyte proliferation in the epiphyseal plate, leading to bone lengthening.