tissues Flashcards
1
Q
what is extracellular matrix
A
- flexible, loose lattice matrix, structure, support, regulation
- network of protein fibres embedded in polysaccharide gel (polysaccharide, collagen, glycoproteins)
- varies from tissue to tissue (bone / cartilage has lots, muscle have little)
- interstitial matrix = connective tissue
- basal lamina = underlines epithelial tissue, connect to tissue beneath
2
Q
what are examples of intercellular connections
A
- tissues, tight, anchoring and gap / communicating
3
Q
what are the types of tissue in the body
A
- epithelial, connective, muscle and nerve (form follows function)
4
Q
what is epithelial tissue
A
- diverse, covers every major surface in body
- simple, stratified / pseudo stratified (layers), squamous (scaly / thin), columnar or cuboidal
5
Q
what is connective tissue
A
- ECM more abundant than cells
- reinforced by protein fibres
- collagen: 3 polypeptides, triple helix, fibrous
- reticulin: mesh linke, binding of layers of tissues
- elastin: cross links between, manipulation, breaks down over time
- structural support (bones / cartilage), metabolism, storing and cushioning / protection (fats / adipose - peripheral nuclei for fat storage, smaller organelles), defence and transport (blood)
6
Q
what is muscle tissue
A
- specialised cells with highly organised fibre network (contractile proteins, actin / myosin)
- motors of body, contractions (voluntary / involuntary)
- skeletal: stripes, striations, multi-nucleated, voluntary
- smooth: tapered at ends, multi-nucleated, involuntary
- cardiac: striated, branched, involuntary
7
Q
what is nervous tissue
A
- neurons produce and conduct electrochemical impulses throughout body
- glia: support and insults neurons from foreign materials
- myelin sheath: insultes glial cells / axons
8
Q
what is a communicating / gap cell junction
A
- chemical signalling directly between cells
- allow small molecules or ions to pass for intercellular communication, membranes held apart (contrast tight junctions)
- can open / close gates which are important for containing damage
9
Q
what is osteogenesis imperfecta
A
- genetic disorder, inherited as a dominant trait, children suffer from frequent spontaneous fractures
- lack of production of type 1 collagen, used to make bones
- brittle bones, easily broken
10
Q
what is a tissue cell junction
A
- interdependent, bound by ECM, cell to cell physical connection and chemical communication
11
Q
what is a tight / occluding cell junction
A
- connect membranes of adjacent epithelial cells in a sheet
- cell membranes ‘fused’ by protein bands
- form impermeable membrane
- barrier preventing leakage of extracellular contents between a layer of cells (digestive system)
12
Q
what is a anchoring / desmosome cell junction
A
- physical connection, bind adjacent cells together (molecular velcro)
- form an internal tension reducing network or fibres
- common where mechanical stress occurs
- desmosomes, hemidesmosomes and adherens
