Histology Flashcards
What is a tissue
A group of specialised cells that have a similar function
4 types of tissue
1. Epithelial (epi- covering thelial-layer of cells) 2. Connective 3. Muscular 4. Nervous
What is epithelial tissue
Closesly packed cells arrange in continuous sheets which divide into layers/glands, selective barrier & found in blood vessels, heart, lungs, urinary tract, gastrointestinal tract, skin, eyes, reproductive organs etc
What are the two types of glands
Exocrine - secretes products into ducts eg saliva, milk, sebum, sweat, enzymes
Endocrine- produce hormones which enter interstitial & then diffuse into blood
What is connective tissue
Dermis underneath the skin
Most diverse & abundant tissues in the body, most provide a supportive function (bone & cartilage) others are fluid
Formed of extracellular matrix & widely spaced cells
What is the extracellular matrix
The spaces between cells which determine the functionality of tissue (either fluid, semifluid or calcified) & contains water, hyaluronic acid & chondroitin sulphate
Also contains fibroblasts which produce collagen (strong tissue fibres in bone, ligaments etc) & elastic fibres (strong but stretchy in blood vessel walls, lung tissue etc)
3 types of leukocytes
- Macrophages- engulf foreign cells (phagocytes)
- Lymphocytes- produce antibodies
- Mast cells - release inflammatory chemicals
Functions of connective tissue
Structural framework (bone/cartilage) Transport nutrients & wastes (blood) Protection for vital organs Support & interconnection (tendons/ligaments etc) Insulate (adipose tissue) Store energy Produce blood & lymphatic cells Defense & repair
Four types of membranes in the body
- Cutaneous
- Mucous
- Serous
- Synovial
What is the mucous membrane
Line hollow organs that open to a surfsce of the body eg entire digestive, respiratory & genitourary tracts
In the digestive system, the membrane secretes enzymes needed for digestion & also acts as the site for absorption
What is the serous membrane
Line body cavities that do not open to the exterior
They are double-layered containing inner ‘visceral’ which surrounds organs & outer ‘parietal’ that lines a cavity. Between these layers lies serous fluid which snables an organ to glide freely within the cavity without friction
Three serous membranes in the body
- Pleura - lines thoracic cavity & surrounds lungs
- Pericardium - surrounds the heart
- Peritonium - lines the abdominal cavity & surrounds abdominal & pelvic organs
What is the cutaneous membrane
The skin
What is the synovial membrane
Line cavities of freely movable joints in the body
Contains cells called synoviocytes which secrete synovial fluid. This lubricates & nourishes joint cavities they line
Also surround tendons that could be injured by rubbing against bones eg wrist
