Lect Chapter 4a-4b Flashcards
What are the 4 basic tissue types?
Epithelial
Connective
Muscle
Nervous tissue
What steps need to be done to view tissues microscopically?
- Fixed - preserved
- Sectioned - cut to thin slices
- Stained - to contrast different structures
What are two main forms of epithelial tissue?
- Covering and lining
2. Glandular
What are the main functions of epithelia?
- protection
- absorption
- filtration
- excretion
- secretion (enzymes)
- sensory reception
Five distinguishing charactaristics of epithelium
- Polarity
- Specialized contacts
- Supported by connective tissues
- Avascular (no blood supply done by diffusion) and innervated (has nerves)
- regeneration
Explain the polarity of epithelial tissue
Cells have polarity (top and bottom)
Cells have an APICAL surface, upper side exposed to the surface /cavity.
AND
a BASAL side, lower part, attached to basal lamina (inward to body) adhesive sheet holds basal surface of epi.
Explain the specialized contacts of epithelial tissue
Need to fit close together
Specialized contact points bind cells together with tight junctions and desmosomes.
Explain how the epithelial tissue is supported by connective tissue
- reticular lamina
Deep in the basal lamina
Consists of network of collagen fibers
- Basement membrane
Made up of basal and reticular lamina
Reinforces epithelial sheets
Resist stretching and tearing
Defines epithelial boundary
Explain the avascular but innervated charactaristic of epithelial tissue
- has no blood vessels could be nourished by diffusion
- supplied with nerve Fibers
Explain the regeneration characteristic of epithelial tissue
- Begins with loss of apical-basal polarity and broken lateral contact
- friction and hostile substances = damage
Must be replaced
Needs nutrients and cell division
How are epithelial cells named and what fare they?
- first name is SIMPLE - one layer of cells or STRATIFIED - two or more layers thick involved in protection
- second name indicated shape
Squamous
Cuboidal
Columnar
What processes involve simple epithelia
Tricky not just squamous
Absorption
Secretion
Filtration
Describe simple squamous epithelium, what is their function and name 2 special simple squamous epithelia.
Single flat layer of disc-shaped cells w little cytoplasm.
Allow materials to pass by diffusion and filtration and secretes lubrication substances.
Endothelium - lines lymph vessels, blood vessels and heart
Mesothelium - serous membranes in the ventral body cavity
Where are some places simple squamous epithelia is found
Kidneys, lungs, lining the heart, lymphatic vessels
Describe simple cuboidal epi, their function, and location found
Single layer of cube-like cells w large central nuclei
Secretion and absorption
Kidney tubules
Ducts and secretory portions of small glands
Describe simple columnar epi, their function, and location found
Single tall layer of closely packed cells with nucleus in a row.
Some cells have cilia some microvilli
Some layers contain goblet cells that
secrete mucus
Non-ciliated type; Absorption
Secretion of mucus, enzymes, and other subs
Ciliated type; Movement of mucus
Movement of reproductive cells
Describe pseudostratified columnar epithelium, function, and location found.
Look stratified but are a single layer of cells of varying heights some not reaching the exposed ares. Nuclei r at diff levels. May contain mucus secreting cells. Have cilia
Secrete subs *mucus
Move mucus via Cilia
Mostly an upper respiratory tract, doctors of large glands, and tubules of testes
Describe Stratified squamous epithelium, function, and location found
Thick membrane made of several cell layers. Basal layers are cuboidal or columnar Surface cells or squamous. Keratinized cells found on the upper layer of skin, non-keratinized cells found in moist linings
Primarily for protection
Keratinized version forms the skin
Non-keratinized versions for moist linings of esophagus mouth vagina anus
Describe stratified cuboidal epithelium, function, and location found
Usually only two cell layers thick
Found in some Sweat and Mammary glands
Describe Stratified columnar epithelium, function, and location found
Only the apical layer is columnar
Small amounts found in pharynx mail urethra and lightning some glandular ducts
Usually only occurs at transition areas between two other types of epithelia
Describe transitional epithelium, function, and location found
Basal cells are cuboidal or columnar surface cells are dome shaped or squamous like
Stretches readily and permits stored urine to distend urinary Organ
Ureters, bladder, part of the router
How are glands classified And explain?
- site of product release:
Endocrine - Internally secreting
Exocrine – externally secreting - Number of cells forming the gland
Unicellular - goblet cells or
multicellular – salivary
Describe Endocrine glands, and how and where they secrete?
– Ductless glands
- secreted by exocytosis
The hormone secreted travel through lymph or blood to target organs
Describe Exocrine glands, and how do they secrete
- They have ducts
Can be UNI or multicellular - Secrete products via ducts onto body surfaces example skin or into body cavities.
Mucus, sweat, oil and salivary glands
