Chapter 4: Histology Flashcards
Define Histology and name the four tissue types.
Histology: The study of the microscopic structure of tissues and how they function within organs
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
Where is epithelial tissue found in the body?
Throughout the body covering and lining various surfaces and structures:
- Skin
- Lining of organs
- Glands
- Blood vessels
- Lining body cavities
Compare covering / lining epithelia with glandular epithelia.
Covering/lining epithelia mainly protect and cover surfaces, while glandular epithelia specialize in secretion.
Covering/Lining epithelia-
Location: On surfaces of body and lining internal cavities and organs
Function: Provides protection, absorption, filtration, and secretion, acts as a barrier and interface with the external environment
Structure: Arranged in layers, either simple or stratified
Glandular Epithelia-
Location: Found in glands such as thyroid, sweat glands, and salivary glands.
Function: Specialized for secretion. Produces and releases substances like hormones, enzymes, and mucus.
Structure: Forms the functional units of glands and can be classified into endocrine and exocrine glands.
What is a lumen?
The hallow, inner space or cavity within a tubular structure or organ.
Describe the basic structure and function of mucous membranes, the cutaneous membrane, and serous membranes.
Mucous Membranes: Epithelial tissue over connective tissue, secretes mucus for moisture and protection. Found in cavities open to the outside (e.g., respiratory, digestive).
Cutaneous Membrane (Skin): Stratified squamous epithelium over connective tissue, acts as a protective barrier. Covers the body.
Serous Membranes: Simple squamous epithelium, secretes serous fluid to reduce friction. Lines closed cavities (e.g., pleural, pericardial).
Does epithelium have a blood supply?
No, epithelium does not have blood supply
How does epithelium receive its nutrition and oxygen supply?
Epithelium is avascular, it relies on diffusion from nearby connective tissues for nutrients and oxygen.
Does epithelium have a nerve supply?
Yes, epithelium has nerve supply
Name and describe the classifications of epithelial tissues.
Squamous: Flat cells
Cuboidal: Cube-shaped
Columnar: Tall cells
Transitional: Can merge from cuboidal to squamous
Simple: Single layer
Stratified: Multiple layers
Pseudostratified: One layer that looks like multiple (Respiratory)
What are the names given to the sides and surfaces of the epithelial cell?
Apical Surface: Faces lumen/external environment; may have microvilli/cilia.
Lateral Surface: Sides facing neighboring cells; contains junctions (tight, gap, desmosomes).
Basal Surface: Attached to underlying connective tissue via the basement membrane; anchors epithelium.
Describe the basic structure and function of glands.
Structure:
Exocrine Glands: Secrete substances via ducts (e.g., sweat, saliva).
Endocrine Glands: Release hormones directly into the bloodstream (no ducts).
Function:
Secretion: Produce and release enzymes, hormones, mucus, and sweat.
Regulation: Maintain homeostasis (e.g., metabolism, growth).
Compare exocrine and endocrine glands.
Exocrine Glands: Secrete substances via ducts (e.g., sweat, saliva).
Endocrine Glands: Release hormones directly into the bloodstream (no ducts)
Summarize the different functions of epithelial tissue.
Protection: Shields underlying tissues from injury, pathogens, and chemical exposure.
Absorption: Facilitates nutrient uptake (e.g., in intestines).
Secretion: Produces and releases substances like enzymes and hormones (e.g., glands).
Excretion: Eliminates waste products (e.g., kidneys).
Filtration: Allows selective passage of materials (e.g., in kidneys).
Sensation: Contains sensory receptors for touch, taste, and other stimuli.
Describe the general features of connective tissue: cell and matrix (ground substance and fibers). What types of cells are found in connective tissues?
Cells:
- Fibroblasts: Produce fibers & ground substance.
- Adipocytes: Store fat.
- Macrophages: Immune response.
- Mast cells: Release histamine.
- White blood cells: Immune function.
Matrix:
- Ground Substance: Fills space; supports cells.
- Fibers: [Collagen: Strength.], [Elastic: Stretch.], [Reticular: Supportive network.]
Describe the classes and subclasses of connective tissue (loose: areolar…etc)
Loose Connective Tissue:
- Areolar: Supports organs, holds fluids.
- Adipose: Stores fat, insulates.
- Reticular: Supports lymphoid organs (spleen, lymph nodes).
Dense Connective Tissue:
- Dense Regular: Parallel collagen fibers, strong (tendons, ligaments).
- Dense Irregular: Irregularly arranged fibers, resists tension (dermis).
Specialized Connective Tissue:
- Cartilage: Flexible support (hyaline, elastic, fibrocartilage).
- Bone: Rigid support, mineral storage.
- Blood: Transports nutrients, gases, and waste.
