Chapter 4 Flashcards
(40 cards)
Define tissue:
a group of similarly structured
cells specialized to perform a specific
function
What are the four types of tissues and what is their basic function?
- Epithelium- covers
- Connective- supports
- Muscular- movement
- Nervous- controls
Define epithelia tissue also known as eplithelium
occurs as sheets of tightly packed cells that cover body surfaces and line internal organs and cavities
What are the two subtypes of epithelium
- lining and covering
2. glandular
What is a Basement membrane
a dense mat of extracellular matrix consisting of fibrous proteins and sticky polysaccharides that anchors the epithelium to underlying tissues
(basal lamina + reticular lamina)
Characteristics of epithelia tissue
+ 3 surfaces: -free or apical
-lateral
-basal
+ Specialized cell content (Tight junctions and desmosomes)
+ Can undergo mitosis to replace themselves
+ Supported by connective tissue
Function of epithelia tissue
- Protecting underlying tissues
- Barrier
- Allows substances to pass through
- Secretes, absorbs, and excretes substances
- Sensory reception
Layers of epithelium
- Simple: single layer of cells –> absorption, secretion, and filtration
- Stratified: multiple layers –> protection (wear and tear)
- Pseudostratified: actually simple, appears stratified
Shapes of epithelium
Other aspects regarding shape of epithelium
- Squamous: flattened square shaped
- Cuboidal: cube shaped (dice)
- Columnar: cylinder shape with square end (bricks on end)
- Transitional: appear cuboidal which round top when relaxed and squamous when stretched
Other:
- Keratinized
- Ciliated
- Microvilli (brushed border)
define glandular epithelium and explain the two types:
Give examples of two types of glands:
Glands are specific cells that make and secrete particular products
Endocrine glands: ductless glands that produce hormones that get secreted via exocytosis directly into extracellular space
Examples: Thyroid gland - controls many aspects of metabolism, growth, and development
Exocrine glands: secretes onto skin or into body cavities via ducts
Example: sweat, mucous, oil, salivary, liver glands, pancreas etc.
Exocrine glands can be either…?
unicellular (ductless) - mucous and goblet cells
multicellular (ducts)
- separate into:
- -simple (non branching) or compound (branching)
- -tubular (tubes) or alveolar (sacs)
Define connective tissue
a sparse population of cells scattered through an extracellular matrix
Three unique characteristics of connective tissue
- Common origin- all arise from mesenchyme (embryonic tissue)
- Degrees of vascularity- avascular to highly vascularized
- Extracellular matrix- non-living meshwork of interlocking fibrous proteins and glycosaminoglycans
• makes connective tissue very robust (resists tearing, abrasion, tension, etc.)
Three main structural elements of connective tissue:
- Ground substance, fibers, and cells
* ECM = ground substance + fibers
What is a ground substance and what is it’s function
Unsaturated material between cells
–composed of interstitial fluid, cell adhesion proteins, and
proteoglycans
+ Cell adhesion proteins = glue for adhesion (laminen, fibronectin
+ Proteoglycans = protein core + glycosaminoglycan
–forms aggregates to trap water
+ Fibres- support and impede (delay or prevent) diffusion
What are the three fibres of connective tissue?
- Collagen fibres: protein collagen, very tough, high tensile strength
- Elastin fibres: long and thin, made of protein elastin, allow connective tissue to stretch and recoil
- Reticular fibres: fine collagenous fibres, extensively branched, found around blood vessels and organs because they have more ‘give’ than collagen
Each class of connective tissue has a resident cell type present in both immature (suffix blast) and mature (suffix cyte) form
Example: fibroblast/ fibrocyte
Fun fact!
Name the types of connective tissue and which cells they consist of:
- Connective tissue proper: fibroblast
- Cartilage: chondroblast
- Bone: osteoblast
- Vesicular (blood and lymph): hematopoietic stem cells
Other cells relative to connective tissue and their functions:
+ Fat cells: store nutrients
+ White blood cells: immunity
+ Mast cells: part of immunity, initiate localized inflammation response– contain heparin, histamine, proteases, and other enzymes
+ Macrophages: phagocytes
5th connective tissue?
Embryonic- mesenchyme- differentiates into all other cell types of connective tissue
Connective tissue proper:
Subtypes of connective tissue proper:
Type of connective tissue
- has matrix composed of fibres in viscous ground fluid
Subtypes:
Loose connective tissue
Dense connective tissue
Loose connective tissue:
Type of connective tissue
A. Areolar: fibers arranged loosely, functions in support and binding
B. Adipose: full of fat cells (adipocytes), little matrix; white fat cells store nutrients
C. Reticular: has reticular fibers, common in lymphatic tissue (nodes, spleen, bone marrow)
Dense connective tissue:
Type of connective tissue
A. Dense regular: collagen fibers run parallel (very strong) forms tendons and ligaments
B. Dense irregular: this bundles of collagen fibers arranged irregularly; located in areas where tension comes from all directions (fascia –surrounds muscle, blood vessels, and nerves– on some organs)
C. Elastic: found in some ligaments (connecting adjacent vertebrae) and in larger arteries (aorta)
Cartilage
Type of connective tissue
Consists of a rubbery matrix containing cartilage fibers with cells called chondrocytes (derived from chondroblasts)
Withstand tension and compression
