O Flashcards
What is the primary function of unicellular organisms?
All functions like digestion, respiration, and reproduction are performed by a single cell.
What is tissue in multicellular animals?
A group of similar cells along with intercellular substances that perform a specific function.
How are tissues categorized based on cell structure and function?
Four types:
* Epithelial
* Connective
* Muscular
* Neural
What is an organ?
A structure formed by organized tissues to perform a specific function.
What constitutes an organ system?
Two or more organs that perform a common function through interaction.
What are the two types of epithelial tissues?
Simple epithelium and compound epithelium.
What is the characteristic of epithelial tissue?
Cells are compactly packed with little intercellular space.
What is the basement membrane?
A non-cellular layer made of glycoprotein, mucopolysaccharide, and collagen fibers.
Why is epithelial tissue avascular?
Due to minimal intercellular space, blood vessels cannot penetrate it.
What is simple epithelium?
Composed of a single layer of cells that lines body cavities, ducts, and tubes.
What is compound epithelium?
Consists of two or more cell layers and has a protective function.
What are the three types of simple epithelium?
- Squamous
- Cuboidal
- Columnar
What is squamous epithelium?
Made of a single thin layer of flattened cells.
What is the function of simple squamous epithelium?
Forms a diffusion boundary and aids in filtration.
What is the cuboidal epithelium?
Composed of a single layer of cube-like cells.
What is the function of cuboidal epithelium?
Secretion and absorption.
What is columnar epithelium?
Composed of a single layer of tall and slender cells.
What modifications occur in cuboidal and columnar epithelium?
Microvilli and cilia may be present on their free surface.
What are microvilli?
Finger-like structures that increase surface area for absorption.
What is brush-bordered epithelium?
Cuboidal or columnar epithelium with microvilli on the free surface.
What is ciliated epithelium?
Cuboidal or columnar cells with cilia on their free surface.
What are the types of glands based on cell composition?
Unicellular and multicellular glands.
What is an exocrine gland?
Glands that release products through ducts to specific locations.
What is an endocrine gland?
Glands that secrete hormones directly into the bloodstream.
What is a heterocrine gland?
A mixed gland with both exocrine and endocrine functions.
What is the primary function of compound epithelium?
To provide protection against chemical and mechanical stress.
What are the types of compound epithelium?
- Transitional epithelium
- Stratified epithelium
What are cell junctions?
Structures made of proteins that link individual cells.
What are the three types of cell junctions?
- Tight junction
- Adherent junction
- Gap junction
What is the function of tight junctions?
Prevent substances from leaking across a tissue.
What do adherent junctions do?
Help in cementing neighboring cells together.
What is the role of gap junctions?
Facilitate communication between adjacent cells.
