Lesson 1: Lining Epithelia Flashcards
What are the main functions of epithelial tissue?
Covers body surfaces, lines cavities, forms glands, protects, absorbs, secretes, and senses.
From which embryonic layers is epithelium derived?
Ectoderm, mesoderm, and endoderm.
What is the basement membrane?
A thin layer anchoring epithelial cells to underlying tissues.
Why is epithelial tissue avascular?
It relies on diffusion for nutrient and waste exchange.
What are the defining general features of epithelial tissue?
Cells are closely apposed, polarity, avascularity, presence of a basement membrane, and regenerative capability.
What is the importance of cell polarity in epithelial tissue?
It ensures directional secretion, absorption, and interaction with the environment.
How does epithelial tissue achieve its regenerative ability?
Through mitotic activity in the basal (germinal) layer.
What is the role of intercellular junctions in epithelial tissue?
To maintain structural integrity and regulate communication between cells.
What are simple epithelia mostly concerned with?
absorption, secretion and filtration
What are stratified epithelia mostly concerned with?
protection of the tissue/organ
Where is simple squamous epithelium typically found?
Lung alveoli, lumen of blood and lymph vessels (endothelium),
serosa (mesothelium), and Bowman capsule (kidney glomeruli)
What is the primary function of simple squamous epithelium?
Diffusion and filtration.
may secrete lubricating substances
Where is simple cuboidal epithelium located?
Kidney tubules, gland ducts, ovary surface, terminal bronchioles, retina.
What is the role of simple cuboidal epithelium?
Secretion and absorption.
What are some locations of simple columnar epithelium?
small intestine, stomach, uterine tubes, small bronchioles bronchi, gallbladder, excretory ducts.
How does simple columnar epithelium support absorption?
Through microvilli on the apical surface.
How does the simple squamous epithelium facilitate gas exchange?
Its thin structure allows efficient diffusion in alveoli.
What is the function of mesothelium derived from simple squamous epithelium?
To secrete lubricating fluid in serous membranes.
How does endothelium in blood vessels contribute to vascular function?
It reduces friction and regulates permeability. (simple squamous)
Why is simple cuboidal epithelium well-suited for kidney tubules?
It provides a balance of absorption and secretion.
Where is simple cuboidal epithelium found in endocrine glands?
In the follicles of the thyroid gland.
How does the structure of simple cuboidal epithelium aid in its function in glandular ducts?
Its cube-like shape offers structural support for secretory activity.
What is pseudostratified epithelium?
All cells rest on the basal membrane, but not all reach the apical surface.