human physiology 100 - tissues and membranes

What is epithelial tissue?

- Layers if cells covering exposed surfaces
- lines internal passage ways and chambers
- forms glands
- attached to basal lamina
- no blood supply (a vascular)
- can regenerate

What are tight junctions?

Prevents movement of water and solutes between cells

What are gap junctions?

Allows movement of ions and small molecules between cells

What is a desmosome?

The linking of two cells by cell adhesion molecules (CAMS), proteoglycans and the cytoskeleton.

What is transitional epithelia?

- tolerates repeated cycles of stretching and recoiling to its previous shape without damage

What are endocrine glands?

they release hormones directly into the blood and interstitial fluid, no ducts

What are exocrine glands?

They produce secretions onto epithelial surfaces through ducts

What are the functions of connective tissues?

- connection: binds together, supports and surrounds other tissues
- protection: protects and insulates internal organs
- storage: primary location of stored energy (fat)

What are fibroblasts?

- the most abundant cell type in connective tissue proper
- found in all connective tissue proper
- secrete proteins and hyaluronan (cell cement)

What are fibrocytes?

- 2nd most abundant connective tissue cells
- maintain fibres

What are mesenchymal cells?

- divide when injury occurs producing new daughter cells that can differentiate

What are collagen fibers?

- most common fibres in connective tissue
- long straight, strong and flexible
- eg tendons

What are recticular fibres?

- same protein subuints as collagen fibres
- thin, long and interwoven allowing for strength and flexibility
- interwoven network caller stroma stabilises the surrounding cells of organs

What are elastic fibres?

- comprised of elastin
- allow stretch and return to normal structure

What is ground substance?

- proteoglycans and glycoproteins
- fills spaces between cells and surrounds fibres
- impedes passage of pathogens due to viscosity

What is loose connective tissue and where does it come from?

- the packing materials of the body filling spaces between organs
- cushion and support/stabilise cells in organs and support epithelia
- comes from mesenchyme (embryonic tissue)

What are the three types of loose connective tissue?

areolar, adipose, reticular

What is areolar tissue?

- least specialised loose connective tissue tissue
- open framework, loosely organised
- viscous ground substance and elastic fibres
- holds blood vessels in capillary beds

What is recticular tissue?

- provides support, tough and flexible
- complex, 3D structure/ network
- stroma = supporting fibres
- recticular organs = spleen, liver, lymph nodes, bone marrow

What is dense connective tissue?

- connective tissue proper
- is tightly packed with high numbers of collagen and elastic fibres

What is dense regular connective tissue?

- tightly packed, parallel collagen fibres
- tendons attach muscle to bone
- ligaments connect bone, stabilising organs

What is dense irregular connective tissue?

- interwoven networks of collagen fibres
- strengthens and supports
- is layered in the skin
- perichondrium : around cartilage
- periosteum : around bones

What is elastic tissue?

- made of elastic fibers
- allows tissue to tolerate repeated cycles of expansion

What is fasciae? What are the three types?

- connective tissue layers that support trunk organs connecting them to the rest of the body
1. Deep fasciae
2. Superficial fasciae
3. Sub serous fasciae

What are the types of sqauamous epithelia?

1. Simple squamous epithelia
- diffusion
- mesothelium ( body cavities)
- endothelium ( heart and vessels)
2. Straitified squamous epithelium
- protection
- keratin

What are the types of cuboidal epithelia?

- simple : secretion and absorption
- stratified : sweat ducts and mammary glands

What are the types of columnar epithelia?

- simple : absorption and secretion
- pseudostratified : cilia movement
- stratified : protection

What is fluid connective tissue?

- blood and lymph
- watery matrix of dissolved proteins

What are the four types of membranes?

mucous, serous, cutaneous, synovial

What are the functions of mucous membranes?

- line passageways that have external connections
- in digestive, respiratory, urinary and reproductive tracts
- epithelia surfaces must be moist to reduce friction and facilitate absorption and excretion

What are the functions of serous membranes?

- line cavities not open to the outside
- are thin but strong
- have fluid transudate to reduce friction

What are the three layers of the serous membrane?

1. Pleura
- lines pleural cavities
- covers lungs
2. Peritomeum
- lines peritoneal cavity
- covers abdominal organs
3. Pericardium
- lines pericardial cavity
- covers heart

What are synovial membranes?

- line articulating joint cavities
- produce synovial fluid
- protect the ends of bones
- lack a true epithelium