Epithelium Tissue and Exocrine Glands

Questions and Answers

What is a tissue?

A group of similar cells and extracellular materials that perform a common function.

What are the four major tissue types?

Muscle (correct)

Epithelial (correct)

Connective (correct)

Nervous (correct)

How does epithelial tissue occur?

As a sheet of cells that covers a body surface or lines a body cavity.

Epithelial tissue has a _____ amount of intercellular matrix compared to other tissues.

small Signup and view all the answers

What are the functions of epithelial tissue?

Protect, sensory functions, secretion, absorption, filtration, excretion. Signup and view all the answers

What is the arrangement of membranous epithelium?

Covers the body and some of its parts, and lines the serous cavities, blood and lymph vessels, and tracts. Signup and view all the answers

What characterizes glandular epithelial tissue?

Grouped to form the secretory units of endocrine and exocrine glands. Signup and view all the answers

What distinguishes epithelial tissue from other tissue types?

Specialized contacts, polarity, support by connective tissue, avascular but innervated, rapid regeneration. Signup and view all the answers

What are the classifications of membranous epithelium based on shape?

Squamous Signup and view all the answers

What is simple squamous epithelium?

Type of epithelium tissue found in the air sacs of lungs and blood vessels. Signup and view all the answers

Describe simple cuboidal epithelium tissue.

CUBE shaped cells, found in kidneys and most glands. Signup and view all the answers

What is simple columnar epithelium?

RECTANGULAR shaped cells that line most of the digestive and respiratory tract. Signup and view all the answers

What is pseudostratified columnar epithelium?

A single layer of cells that vary in height found in large areas of the respiratory tract. Signup and view all the answers

What is stratified squamous epithelium?

Top layer is squamous, more than one layer of epithelial cells, provides protection. Signup and view all the answers

Describe stratified cuboidal epithelium.

Outermost layer provides protection, found in glands and male urethra. Signup and view all the answers

What is transitional epithelium?

Found in the urinary system, stretchy, can be collapsed when the bladder is empty. Signup and view all the answers

What characterizes glandular epithelium?

Specialized for secretory activity, includes endocrine and exocrine glands. Signup and view all the answers

What can structural classification of exocrine glands include?

Tubular or alveolar Signup and view all the answers

Describe apocrine glands.

Collect their secretory products near the apex and release them by pinching off. Signup and view all the answers

What are holocrine glands?

Whole cell self-destructs to release secretions. Signup and view all the answers

What does merocrine classification of exocrine glands mean?

Most glands secrete their products directly through the cell membrane. Signup and view all the answers

Study Notes

Tissue Overview

Tissue comprises a group of similar cells and extracellular materials that perform a common function, essential for maintaining homeostasis.
Four major tissue types include epithelial, connective, muscle, and nervous.

Epithelial Tissue Characteristics

Epithelial tissue forms sheets that cover body surfaces and line cavities, including glandular epithelium (e.g., salivary and sweat glands).
Small amount of intercellular matrix, composed of continuous sheets of cells.

Functions of Epithelial Tissue

Serves protective roles, sensory functions (skin, ear, eye, nose), and involved in secretion, absorption (kidney, digestive tract), filtration (kidneys), and excretion.

Types of Epithelial Tissue Arrangement

Membranous epithelium covers surfaces and lines serous cavities, blood and lymph vessels, and various tracts (respiratory, digestive, genitourinary).
Glandular epithelium forms secretory units for both endocrine (ductless, hormonal) and exocrine glands (release products into ducts).

Distinguishing Features of Epithelial Tissue

Specialized contacts with desmosomes and tight junctions.
Defined polarity with distinct apical and basal surfaces differing in structure and function.
Supported by connective tissue.
Avascular but innervated, meaning it lacks blood vessels but has nerve supply.
High regeneration capability, allowing rapid replacement.

Classification of Membranous Epithelium

Based on cell shape: squamous (flat), cuboidal (cube-shaped), and columnar (tall and rectangular).
Based on cellular layers: simple (one layer) and stratified (multiple layers).

Specific Types of Epithelial Tissue

Simple Squamous Epithelium: Found in air sacs of lungs and blood vessels, resembles scrambled eggs.
Simple Cuboidal Epithelium: Cube-shaped cells located in kidneys and glands.
Simple Columnar Epithelium: Rectangular, lining digestive and respiratory tracts (bronchioles), can be ciliated or non-ciliated.
Pseudostratified Columnar Epithelium: Appears stratified but is a single layer with varying heights, mainly in the respiratory tract and urethra.
Stratified Squamous Epithelium: Multiple layers with the top layer being squamous, designed for protection.
Stratified Cuboidal Epithelium: Provides protection and is found in glands and male urethra.
Stratified Columnar Epithelium: Present in male urethra and salivary glands, consisting of more than one layer.
Transitional Epithelium: Found in the urinary system, allows stretching and collapsing of the bladder.

Glandular Epithelium

Specialized for secretory activity; includes unicellular and multicellular glands.
Endocrine glands release hormones directly into the bloodstream.
Exocrine glands release products through ducts, such as sweat and saliva.

Structural Classification of Exocrine Glands

Can be unicellular (e.g., goblet cells) or multicellular.
Multicellular glands can be tubular or alveolar (sac-like).
Classification into simple glands (single duct) and compound glands (multiple ducts).

Functional Classification of Exocrine Glands

Apocrine Glands: Collect secretory products near the apex; involve cell damage during secretion but repair quickly, possibly located in mammary tissue and certain sweat glands.
Holocrine Glands: Entire cell ruptures to release secretion (e.g., sebaceous glands).
Merocrine Glands: Most common type; secrete products directly through the cell membrane without cell destruction.

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Description

This quiz covers key concepts related to epithelial tissue and the structural classification of exocrine glands. It includes definitions and classifications crucial for understanding tissue functionality and organization. Ideal for students studying histology or related biological sciences.