Epithelial Tissue

transitional epithelium (look for dome shape)

-Forms lining of hollow urinary organs -Found in bladder, ureters, and urethra -Basal layer cells are cuboidal or columnar -Ability of cells to change shape when stretched allows for increased flow of urine and, in the case of bladder, more storage space

stratified squamous epithelium

-Free surface is squamous, with deeper cuboidal or columnar layers -Located in areas of high wear and tear (example: skin) -Keratinized cells found in skin; nonkeratinized cells are found in moist linings (vagina)

stratified epithelial tissue

-Involve two or more layers of cells -New cells regenerate from below --Basal cells divide and migrate toward surface -More durable than simple epithelia because protection is the major role

Simple columnar epithelium

-Single layer of tall, closely packed cells -Some cells have microvilli, and some have cilia -Some layers contain mucus-secreting goblet cells -Involved in absorption and secretion of mucus, enzymes, and other substances -Ciliated cells move mucus -Found in digestive tract, gallbladder, ducts of some glands, bronchi, and uterine tubes

origins of epithelium

-from all three embryonic germ layers https://youtu.be/y4QjEcZrVXg -skin, lining of mouth, nose and anus from ectoderm "attractoderm" - personality (cns),skin mouth, anus, -lining of respiratory and digestive tract, glands of digestive tract from endoderm ductoderm- (tubes) digestive llp digestive tract, lungs, liver, pancreas -endothelium of blood vessels, mesothelium of body cavities, tubules of kidney, lining of reproductive tract from mesoderm "musclederm- muscles and other athlete" cadriovascular, urinary anc reproductive

Unicellular exocrine glands where are they found?

-mucous cells and goblet cells -Found in epithelial linings of intestinal and respiratory tracts

two names of epithelial tissues

1- number of cells a. simple- single b. stratified-many 2- shape of cells a. squamous- flat "squished" b. cuboidal- box c. columnar- column

How are glands classified?

1. By the ways the glands secrete their products 2. number of cells that form the gland

Two main forms of epithelial tissue

1. Covering and lining epithelia 2. Glandular epithelia

How are tissues processed?

1. fresh tissue is fixed them embed 2. a small cut (section) is taken 3. stained for viewing

What kind of epithelium: A. air sacs of lungs, Kidney Bowman capsule B. Glands (thyroid), Kidney Tubules C. Intestine (jejunum) D. respiratory tract (trachea) E. esophagus, vagina F. Skin G. Rare- glands sweat and mammary glands H. Salivary duct, male urethra I. Bladder

A. simple squamous B. simple cuboidal C.simple columnar D. pseudostratified ciliated columnar E stratified non- keratinized squamous F. stratified keratinized squamous G. Stratified cuboidal H. Stratified columnar I. transitional epithelium

multicellular exocrine glands structures

Can be simple or compound.... (by start of duct) each of those can be tubular or alveolar (by terminal end "secretary cell"

multicellular exocrine glands mnemonic

Cheese Sandwiches Feel Nutritious Since Cheese Provides Saturatedfat 5 simple, 3 compound Tubular, branched, alveolar

Simple columnar and cuboidal are both for involved in secretion and absorption... But whats the difference?

Columnar focuses on the secretion of more complex substances. Ex: mucus goblet cells

Ductless glands Secretions are not released into a duct; are released into surrounding interstitial fluid, which is picked up by circulatory system

Endocrine glands

2 types of glandular epithelium

Endocrine- internally secreting (hormones) Exocrine- externally secreting (sweat)

Two special kinds of simple squamous epethelia

Endothelium: Mesothelium:

___________- is a sheet of cells that covers body surfaces or cavities Main functions: protection, absorption, filtration, excretion, secretion, and sensory reception

Epithelial tissue

How do endocrine glands secrete hormones?

Exocytosis

What are tissues?

Groups of cells that are similar in structure and function that preform a related function

General characteristics of epethelia

P Cup BRA Polarized- Apical surface is different than basal surface (functions are different) Contiguous- Share common boarder( touching) Basal lamina OR Basement membrane (basal lamina+ reticular lamina) Regenerative- self healing Avascular (innervated)- no blood vessels, but can have nerves

Serous cells (glands)

Produce watery secretions mostly containing proteins "serous acinus" (e.g. digestive enzymes) Cells have pyramidal morphology Basal nuclei Intensely basophilic basal region due to abundant RNA/polyribosomes Light-staining granules concentrated in apical region Small central lumen

stratified cuboidal epithelium

Quite rare Found in some sweat and mammary glands Typically only two cell layers thick

Mucous cells

Secrete hydrophilic glycoproteins (mucins) Hydrated mucins form viscous gel Pyramidal cells with basal (often flattened) nuclei Pale cytoplasm May form acini or tubules Large central lumen

Mucous cells

Secrete hydrophilic glycoproteins "mucous acinus" (mucins) Hydrated mucins form viscous gel Pyramidal cells with basal (often flattened) nuclei Pale cytoplasm May form acini or tubules Large central lumen

3 different tissue types in kidneys, and their locations

Simple squamous- parietal layer of bowmans capsule Simple cuboidal- Proximal distal and collecting tubules Simple columnar - papillary ducts

multicellular exocrine glands list

Simple tubular- colon Simple coiled tubular- Sweat glands Simple branched tubular- fundic glands- stomach simple alveolar- none simple branched alveolar- Sebaceous Compound Tubular- Cardiac glands of stomach compound alveolar- pancreas compound tubuloalveolar- salivary glands

Difference in simple, compound... and tubular, alveolar exocrine glands

Simple- have unbranched ducts Compound- branched ducts Tubular- secretary cells form a duct (the ends) Alveolar glands- cells for sacs

What does all Unicellular exocrine glands produce?

-All produce mucin, a sugar-protein that can dissolve in water to form mucus, a slimy protective, lubricating coating

Apocrine found where?

accumulate products within, but only apex ruptures; APO=APEX whether this type exists in humans is controversial (maybe mammary cells?)

Holocrine found where?

accumulate products within, then rupture (sebaceous oil glands) Sebaceous glands HOLOcrine WHOLE cell ruptures

How to identify a tissue type?

apical layer

Levels of physiology

chemical- cellullar- tissue- organ- organ system- organism

functions of epidermis

epidermis- psats Protection or selectively permeable barrier Secretion Absorption Transcellular transport Sensation

Difference between endocrine and exocrine glands in relation to surface epethelium

exocrine glands- retain connection with surface with ducts endocrine- lose connection with surface

Unicellular/ multicellular gland examples

goblet cell/ salivary

Pseudostratified columnar epithelium

-Cells vary in height and appear to be multi-layered and stratified, but tissue is in fact single-layered simple epithelium ---"Pseudo" means false ---Many cells are ciliated -Involved in secretion, particularly of mucus, and also in movement of mucus via ciliary sweeping action -Located mostly in upper respiratory tract, ducts of large glands, and tubules in testes

simple cuboidal epithelium

-Single layer of cells -Involved in secretion and absorption -Forms walls of smallest ducts of glands and many kidney tubules

stratified columnar epithelium

Also very limited distribution in body Small amounts found in pharynx, in male urethra, and lining some glandular ducts Usually occurs at transition areas between two other types of epithelia Only apical layer is columnar

Mixed glands

Contain both serous and mucous cells e.g. submandibular gland: --90% serous acinar cells --10% mucous tubules with serous demilunes

Mixed glands

Contain both serous and mucous cells secrete "mixed acinus" e.g. submandibular gland: --90% serous acinar cells --10% mucous tubules with serous demilunes

Locations of keratinzed and non keratinized

keratin- skin non- vocal chords, vagina

Keratinized vs non-keratinized epithelium

keratinized has no nucleus. dead skin

types of multicellular exocrine glands

look at entrance (duct)

Modes of secretion of multicellular exocrine glands

merocrine holocrine apocrine

What are hormones?

messenger chemicals that travel through lymph or blood to their specific target organs Target organs respond in some characteristic way

Where is endothelium found?

Lining of blood vessels, chambers of the heart and lymphatic vessels

Another name for brush boarder

Microvilli

Simple squamous figure of lungs

Need thin layer for gas exchange

What is a gland?

One or more cells that makes and secretes an aqueous fluid called a secretion

Types of secretions glands

Serous acinus mucous acinus mixed acinus

Cells are flattened laterally, and cytoplasm is sparse Function where rapid diffusion is priority

Simple squamous epithelium

Four basic tissue types

epithelial, connective, muscle, nervous

merocrine (eccrine) glands where?

most secrete products by exocytosis as secretions are produced (sweat, salivary, pancreas)

what is Mucous acinus? What is it secreted by? Where?

more viscous secretion high in carbohydrates pyramidal cell with basal (frequently flattened) nuclei clear cytoplasm large central lumen

Mixed acinus? Secreted by? Found where?

mucous acinus with serous demilune intracellular channels deliver serous secretions to lumen

pain receptors are

nociceptors

Where is mesothelium found?

serous membranes in the ventral body cavity

What kind of epithelia is Involved in absorption, secretion, or filtration processes

simple

types of epithelial tissue

simple, stratified, pseudo-stratified squamous, cuboidal, columnar

Least common epithelium

stratified cuboidal. only sweat and mammary glands

What is the most widespread stratified epithelia?

stratified squamous

Simple squamous mesothelium

the epithelium that lines the pleurae, peritoneum, and pericardium

conjuctiva

the mucous membrane that covers the front of the eye and lines the inside of the eyelids.

What is histology?

the study of the microscopic structure of tissues

What is serous acinus? What is it secreted by? Where is it found?

thin, watery secretion usually containing proteins secreted by pyramidal cells with basal nuclei secretory granules in apical cytoplasm small central lumen

Dome shaped cells

transitional epethelium

What is the basal lamina?

type IV collagen + glycoproteins part of basement membrane