Epithelial & Connective Tissue and Integumentary System: Study Guide

Study Guide - Smart Notes

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Anchoring: Epithelial cells are anchored to underlying connective tissue by a basement membrane, providing structural support and regulating cell behavior.
Polarity: Epithelial cells exhibit polarity, meaning they have an apical (top) surface facing the lumen or outside, and a basal (bottom) surface attached to the basement membrane.
Vascularity: Epithelial tissues are avascular (lack blood vessels) and receive nutrients via diffusion from underlying connective tissues.

Simple Squamous: Single layer of flat cells (e.g., alveoli of lungs, lining of blood vessels).
Simple Cuboidal: Single layer of cube-shaped cells (e.g., kidney tubules, glands).
Simple Columnar: Single layer of tall, column-like cells (e.g., lining of digestive tract).
Stratified Squamous: Multiple layers, surface cells are flat (e.g., skin epidermis, oral cavity).
Stratified Cuboidal/Columnar: Rare, found in some ducts (e.g., sweat glands).
Pseudostratified Columnar: Appears layered but all cells touch the basement membrane (e.g., respiratory tract).
Transitional: Multiple layers, cells change shape (e.g., urinary bladder).

Merocrine Secretion: Products released by exocytosis (e.g., salivary glands, sweat glands).
Apocrine Secretion: Part of the cell membrane buds off with secretion (e.g., mammary glands).
Holocrine Secretion: Entire cell disintegrates to release contents (e.g., sebaceous glands).

Endocrine Glands: Ductless, secrete hormones directly into the bloodstream (e.g., thyroid gland).
Exocrine Glands: Secrete products into ducts that open onto surfaces (e.g., sweat, salivary glands).

Unicellular: Single secretory cell (e.g., goblet cell in intestinal lining).
Multicellular: Composed of many cells, often with ducts (e.g., sweat glands).

Mucous Membranes: Line body cavities open to the exterior (e.g., digestive, respiratory tracts).
Serous Membranes: Line closed body cavities (e.g., peritoneum, pleura).
Cutaneous Membrane: The skin; covers the body surface.
Synovial Membranes: Line joint cavities.

Loose Connective Tissue: Areolar, adipose, reticular (e.g., under epithelia, fat storage).
Dense Connective Tissue: Dense regular (tendons), dense irregular (dermis), elastic (walls of arteries).
Cartilage: Hyaline (trachea), elastic (ear), fibrocartilage (intervertebral discs).
Bone: Compact and spongy bone (skeleton).
Blood: Fluid connective tissue (within blood vessels).

Generalities: Avascular, composed of keratinized stratified squamous epithelium.
Types of Cells: Keratinocytes (produce keratin), melanocytes (produce melanin), Langerhans cells (immune), Merkel cells (sensory).
5 Layers of Skin (from deep to superficial):
1. Stratum Basale (germinativum): single row of stem cells, site of mitosis, contains melanocytes.
2. Stratum Spinosum: several layers, contains pre-keratin filaments.
3. Stratum Granulosum: 3-5 layers, keratinization begins.
4. Stratum Lucidum: only in thick skin (palms, soles).
5. Stratum Corneum: many layers of dead, keratinized cells.

Layers:
- Papillary Layer: Areolar connective tissue, contains dermal papillae (form fingerprints), capillaries, and sensory receptors.
- Reticular Layer: Dense irregular connective tissue, provides strength and elasticity, contains hair follicles, sweat glands, and deeper blood vessels.

Cleavage Lines: Natural orientation of collagen fibers; incisions parallel to these lines heal better.
Keloids: Overgrowth of scar tissue at the site of a healed skin injury.

Basal Cell Carcinoma: Most common, arises from stratum basale, rarely metastasizes.
Melanoma: Cancer of melanocytes, highly metastatic and dangerous.
Incidence and Location: Varies by type and region; sun-exposed areas are most at risk.
WA State Incidence vs. US Stats: (Additional info: Compare local and national rates for context.)

Types (Levels):
- First-degree: Only epidermis affected (redness, pain).
- Second-degree: Epidermis and part of dermis (blisters, pain).
- Third-degree: Full thickness, destroys epidermis and dermis (may appear white or charred, no pain in area due to nerve damage).
Rule of 9s: Used to estimate the percentage of body surface area burned. The body is divided into regions, each representing 9% (or multiples) of total body area. Example: Anterior and posterior trunk = 36%, each arm = 9%, each leg = 18%, head = 9%, perineum = 1%.

Types and Functions: Protection, sensation, reduction of heat loss.
Tissue of Origin: Derived from epidermal cells.
Arrector Pili Muscle: Smooth muscle attached to hair follicle; causes "goosebumps" when contracted.

Merocrine (Eccrine) Glands: Widely distributed, secrete watery sweat for thermoregulation.
Apocrine Glands: Found in axillary and genital areas, secrete thicker, milky sweat; become active at puberty.

Feature	Epithelial Tissue	Connective Tissue
Cellularity	High (cells tightly packed)	Low (cells scattered in matrix)
Vascularity	Avascular	Usually vascular (except cartilage)
Matrix	Minimal	Abundant extracellular matrix
Functions	Covering, lining, secretion, absorption	Support, binding, protection, transport

Be able to draw and label the layers of the skin, including sublayers and associated structures (e.g., hair follicle, sweat gland, sensory receptors).
Understand the significance of melanocytes in skin color and protection against UV radiation.
Review the histology of the stratum basale and its role in skin regeneration.