Epitheleal Tissue Flashcards
List 5 strucutures of Epithelia Tissue
- Arranged in Continuous from either Single or Multiple.
- Tightly packed together leaving minimal space for intercellular
- They are Avascular, for nutrient exchange and waste removal through diffusion
- Has high Mitotic Index for regeneration.
Functions of Epitheleal Tissue
Protection: Shields tissues from damage, pathogens, and dehydration.
Secretion: Releases substances like mucus, hormones, and enzymes.
Absorption: Takes in nutrients, mainly in the gastrointestinal tract.
Gaseous Exchange: Facilitates the exchange of oxygen and carbon dioxide.
Excretion: Eliminates waste, such as in the urinary system.
Filtration: Controls substance passage, like in the kidneys.
Sensation: Contains sensory receptors for environmental changes.
The types of Epitheleal tissue which exist are?
Surface Epitheluim
Glandualr Epitheluim
What is the role of the two types of Epithelia tissue
Surface Epitheluim
- It forms the outer layer including the internal organs
- Lines Blood vessels, Cavities,Digestive, Respiratory,Urinary system.
Glandular Epitheluim
- Forms the secretary gland of thyroid,adrenal, sweat,digestive gland.
Function of a Base Membrane
- Reinforces epitheleal tissue preventing it from stretching and tearing
- Attaches epitheluim tissue to the connective
- provide a surface for cell migration during growth or healing
- Restrict the movement of large molecule btwn tissues
- Filters blood in the kidney through Urinary formation.
The 4 Classification of epithelia
- Simple Epithelium
It is a single layer which allows diffusion, osmosis, filtration, secretion, absorption.
- Pseudostratisfied
Epithelium
Pseudo, means fake indicating the misleading appearance of multiple layers due to nuclei at different levels, but all cells rest on basement memebrane reaching the apical surface may have a cilia.
- Stratisfied Epithelium
Consist of two or more layers that provide protection to underlying tissues especially in arears prone to wear and tear. - Glandular Epithelium
A glandular is a single cell that secretes substances into ducts onto surface or into blood. the fuction of a glandular is secretion.
types of Gland
- Endocrine gland: Ductless secretes internally e.g hormones usually multicellular.
- Exocrine gland: Secrete products (e.g., mucus, sweat, oil) onto surfaces or cavities via ducts.
Classification of epithelia tissue part (2)
( Simple Squamous epithelia) list the three location and function
location
- Air Sac of lungs
- Lymphatic vessels
- lining of the heart
- blood vessels
Function :
deals with the Diffusion,filtration
Simple cuboidal epithelia
Location
- Ducts
- Secretory gland
-
Types of exocrine glands:Unicellular exocrine glands;
Goblet is an example of unicellular exocrine gland, Explain how the structure of goblet cells is adapted to their function.
- Highly polarized, with organelles at the base and mucin granules at the
apical surface. - Produce mucin, which acts as a lubricant and defense against pathogens.
- Short microvilli increase the secretion area.
- Found in the respiratory, reproductive, and lower gastrointestinal tracts, surrounded by columnar cells.
Multicellular exocrine glands are composed of what?
Multicellular exocrine glands are made up of a duct and a secretory unit, supported by connective tissue.
Differences btwn Simple and Compound multicellular exocrine glands?
- Simple glands have unbranched ducts
- Compound glands have a branching duct system.)
List the Classification of the secretory portion of multicellular exocrine glands?
Tubular, Acinar (Alveolar), Tubuloacinar
Dstinguish each of this classifcations: Tubular, Acinar (Alveolar), Tubuloacinar
The Tubular is shaped as a tube, found in glands such as Intestine and Stomach.
Acinar (Alveolar), it is a Flask-shaped, with a narrow lumen, e.g., pancreas and parotid salivary glands.
Tubuloacinar is a combination of tubular and sac-like dilations, e.g., submandibular and sublingual salivary glands.
Exocrine glands are classified based on their mode of secretion, What are the three main modes of secretion in exocrine glands?
Merocrine/ Apocrine / Holocrine glands
How does the secretion process differ between merocrine apocrine and holocrine glands?
In the Merocrine gland the secretory gland are released by ‘exocytosis’ meaning the secretory glands leaves the cell without any substance e.g paracrine and salivary gland
In Apocrine gland the apical part of the cytoplasm is lost together with the secretory product. e.g Mamarly glands
Holocrine Gland : the entire secretory breaks down discharges both the cell and product e.g Sebaceous glands of the skin.
