Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
Where is epithelium found?
|
Lining external/internal surfaces of body
Provides interfaces between different biological compartments Forms ducts and secretory units of glands |
|
|
What are 4 functions of epithelial cells?
|
Protection
Absorption Secretion Contractility |
|
|
What are the two main types of epithelia?
|
Simple - one cell thick
Stratified - more than one cell thick |
|
|
What are the 5 types of simple epithelia?
|
1. Simple squamous
2. Simple cuboidal 3. Simple columnar 4. Simple columnar ciliated 5. Pseudostratified columnar ciliated (respiratory) |
|
|
Describe simple squamous epithelium
|
Width>height
Suited for diffusion Found in alveoli, capillary walls |
|
|
Describe simple cuboidal epithelium
|
Width=height=depth, round nucleus
Suited for absorption/secretion/excretion Found in kidney tubules, pancreas, salivary glands |
|
|
Describe simple columnar epithelium
|
Height>width, nucleus at basal border
Suited for absorption/secretion Found in stomach, small intestines, gall bladder Often interspersed with goblet cells |
|
|
Describe simple columnar ciliated epithelium
|
Most have cilia
Found in oviduct |
|
|
Describe pseudostratified columnar ciliated epithelium
|
Nuclei not always at basal border, appear >1 cell thick
Found in upper respiratory tract Interspersed with goblet cells |
|
|
Describe stratified squamous epithelium
|
Change morphology as they reach the surface, nuclei become flattened as they reach the surface
Protection from mechanical abrasion but not dessication Found in oral cavity, vaginal canal, anal canal, oesophagus, pharynx |
|
|
Describe stratified squamous keratinised epithelium
|
Layer of keratin on surface
Protection from mechanical abrasion and dessication Found as epidermis |
|
|
Describe stratified cuboidal epithelium
|
Usually 2-3 cell layers thick
Minimal absorption/secretion, more substantial lining than simple cuboidal Found lining ducts e.g. salivary glands |
|
|
Describe stratified columnar epithelium
|
Protection
Found in conjunctiva, distal urethra, salivary gland ducts Often interspersed with goblet cells |
|
|
Describe transitional epithelium
|
Accommodates stretching
Relaxed - 4-5 cell layer thick, sretched - 2-3 thick Found in urinary tract especially bladder |
|
|
What 3 layers make up the basement membrane?
|
Lamina lucida
Lamina densa (visible layer) Lamina fibroreticularis |
|
|
What substances make up the basement membrane?
|
Type IV collagen
Glycoproteins: Laminin, entactin, fibronectin Proteoglycans - heparin sulphate |
|
|
Describe cilia
|
7-10um in length
They beat in "wave-like" motions to move mucus/fluid in a certain direction Made up of pairs of microtubules |
|
|
Describe microvilli
|
0.5-1.0um
Short cytoplasmic processes, they add surface area for absorption Contain several actin filaments |
|
|
Which of the layers does epithelium originate from?
|
All three
Ectoderm - skin, cornea and lens, oral and anal canal Endoderm - digestive tract lining, respiratory system, thyroid and thymus Mesoderm - serous membranes, endothelium of blood and lymph and urogenital system |
