Tissues Flashcards
The types of basic tissues
- Epithelial
- Connective
- Muscle
- Nervous
Functions of epithelium
- Protection from dehydration
- Absorption / secretion
- Filtration
- Forms slippery surfaces
Characteristics of epithelia
- Cellularity
- Specialised contacts
- Polarity
- Support by connective tissues
- Avascular
- Regeneration
Classifications
Surface Epithelia nad Glandular Epithelia
First and Last Name Classifications
Simple and stratified
Squamous, cuboidal, columnar
Simple Squamous Epithelium
A single layer of flat cells with disc-shaped nuclei.
Endothelium: the thin and flattened lining of hollow organs.
Mesothelium: lines serous or ventral cavities and covers the visceral organs of those cavities.
Function of Simple Squamous
- Passage of materials by passive diffusion and filtration
- Secrets lubricating substances in serosae
Location of Squamous Epithelium
- Alveoli of lungs,
- Lining of heart, blood and lymphatic vessels,
- Lining of ventral body cavity
Simple Cuboidal Epithelium
Description: single layer of cube-like cells with large, spherical central nuclei,
Function: secretion and absorption
Location: kidney tubules, secretory portions of small glands, salivary glands and pancreas and ovary surface.
Simple Columnar Epithelium
Description: single-layer of column-shaped cells with oval nuclei. Some bear cilia at their apical surface and many contain goblet cells.
Function: absorption; secretion of mucus, enzymes and other substances. Ciliated type propels mucus or reproductive cells by ciliary action.
Location: non-ciliated: gallbladder, ducts of some glands. Ciliated: small bronchi, uterine tubes and uterus
Stratified Epithelia
Contains two or more layers
- Keratinised - contain protective protein keratin.
- Non-keratinised - forms the moist lining of body openings and times were is wear and tear.
Function: protects underlying tissues in areas subject to abrasion
Locations;
- Keratinised: forms epidermis
Non-keratinised: forms lining of the oesophagus, mouth, anal canal and vagina.
Stratified Cuboidal
- Generally two layers of cube-shaped cells
- Function: protection
- Location: ducts of sweat glands, mammary glands and salivary glands.
Stratified Columnar
Function: protection and secretion
Locations: rare tissue type, male urethra and large ducts of some glands.
Pseudostratified Columnar
In one layer of cells, nuclei are at different levels.
Function: secretion of mucus
Location: -Non ciliated: ducts of male reproductive tubes
Ciliated: lines trachea and most of upper respiratory tract.
Transitional
Basal cells are usually cuboidal or columnar,
Superficial cells are dome-shaped
Function: stretches to permit distention of urinary bladder
Location: Urinary bladder. part of urethra, ureters
How to distinct between transitional and squamous
Transitional are three or four layers while squamous are multiple since they are stratified.
Exocrine Glands
Ducts carry products of exocrine glands to the epithelial surface:
- Mucus-sweating glands,
- Sweat and oil glands,
- Salivary glands
Endocrine Glands
Secrete substances directly into the bloodstream
Produce hormones
Examples: pituitary, adrenal, thyroid.
Extracellular Matrix
Mainly composed of ground substances like water and adhesive proteins and charged polysaccharides.
Fibrillar components
Collagen (tensile support)
Elastic (stretchable fibre)
Reticular (very fine collagen fibres; forms internal skeleton)
Connective tissue
Most diverse tissue,
- Connective tissue proper,
- Cartilage,
- Bone tissue,
- Blood.
Connective tissue proper
Functions:
- Support and binding of other tissues,
- Hoping body fluids,
- Defending the body against infection.
- Formed of loose and dense connective tissue.
Areolar Connective Tissue
- Gel-like matrix with all three protein fibre types.
Function: - Wraps and cushions organs - support,
- Holds and conveys tissue fluid,
- Important role in inflammation
Location:
- Widely distributed under epithelia,
- Packages organs,
- Surrounds capillaries and small nerves.
Adipose Tissue
Insulation and protection of the body and some organs
- Peripheral nuclei.
Reticular Tissue
- Network of interwoven reticular fibres
Dense Connective
Fibrous
- More fibres and fewer cells
- Forms ligaments
- Outer protective covering of organs
Dense Connective Regular
Mainly collagen fibres, rows of fibroblasts.
Cartilage
- Less hard and more flexible than bone
- Cartilage cells are called chondrocytes,
Hyaline
- Many collagen fibres,
- Glassy appearance,
Found in costal surfaces, trachea
Elastic
- Elastic fibres
Found in ear
Fibrocartilage
Tough and slightly flexible
Found in intervertebral discs.
Bone matrix
Consists of organic and inorganic components:
- Organic: type I collagen
- Inorganic: calcium phosphate, bicarbonate
Compact bone
- 80% of the body bone
- Made of a large number tube-shaped units called osteons
Spongy Bone
- Made of trabecular, space in between contains bone marrow
Muscular Tissue
- Contractile tissue; responsible for movement
Skeletal, smooth and cardiac
Nervous Tissue
- Neurons and Neuroglia
Neurons
- Structural and functional unit of the nervous tissue
- Responsible for reception, transmission and processing of stimuli responses.
Neuroglia
Functions: insulate, support and protect neurone
