Tissues Flashcards
Describe epithelial tissue
Rich in cells (tightly bound together) with junctional complexes
Found on surface and lie on a basement membrane
Give functions of epithelia tissues
- Protection
- Absorption
- Diffusion
- Forms glands - secretion
Describe connective tissue/spaces
Few cells which are apart from each other.
Spaces filled with fibres + ground substance + fluid = making the ECM
Function of connective tissue
Connects and supports. ECM defines structural and functional properties
Describe muscle tissue
Elongated thin cells - cytoplasm packed with contractile apparatus.
Types of muscle tissue
Skeletal, smooth, cardiac muscle
Describe nerve tissue and its shape
Angular-shaped neurons, with prominent nucleoli. Surround small support (satellite) cells
Describe the function of nerve tissues
Recieve, generate and transmit electrical signals —> integrate information
How can we classify the different types of epithelium (3)
- shape of surface layer of cells - squamous, cuboidal, columnar
- Number of layers - simple (1 layer), stratified (more than 1)
- Cell surface specialisations - cilia, villi, microvilli, keratin
Give the location and function of simple epithelium
Inside body due to fragile nature: lining of body cavities, blood, lymph vessels, ducts, heart and lungs.
Being thin layer allows for faster: absorption, secretion and filtration
Give the location and function of stratified epithelium
Skin, oesophagus and secretory - glands
Function mostly protective, withstasnding abraision
What is the function and location of pseudostratified columnar epithelium?
Secretion and movement
Found in trachea
Functiona and location of transitional epithelium
Permeability barreir, stretchability
Urinary tract
What are some cell surface specialisations of epithelial cells?
Cilia - respiratory system and the movement of particles
Microvilli - GIT and inc SA for absorption (brush border)
Give the main types/classifications of connective tissue
- Loose CT - areolar, adipose
- Dense CT - dense irregular and dense regular
- Specialised CT - cartilage, bone, blood
Explain Loose (areolar) CT
Aggregation of loosely arrranged fibres and may cells of differing types
Primary location beneath epithelia that cover surfaces or line tubes/cavities
Initial site of defence against bacteria so many trasnsient cell types migrate to loose CT from local blood vessels
Describe Adipose tissue
Specialised Loose CT with abundant fat storing adipocytes
Single large dropled ot lipid pushes nucleus to one side and flattens cytoplasm to a thin rim. Has a rich blood supply.
Function of adipose tissue
Found mostly in CT under skin for insulation and around organs for protection - also to some extent an energy store
Different fat (adipose tissue) colours
White fat - adult
Brown Fat - foetal
Explain dense irregular CT
Thick collagen fibres ruinning in all directions
Can withstand tension exerted in many directions and provides structural strength
Found on dermis of skin, submucosa of digestive tract, fibrous capsules of organs and joints
Explain dense regular CT
Closely packed collagen fibers all running in the same direction and poorly vascularized.
Function: attach muscle to bone/ bone to muscle ad can withstand great tensile stress when a pulling force is applied in one direction
Location: tendons and ligaments
What makes up connective tissue
Cells + ECM
Explain the ECM in detail
- Fibres - collagen, elastic, reticular
- Ground substance (jelly-like) - carb linked to protein (e.g. hyalronic acid - joints)
- Tissue fluid - liquid
3 types of fibres in CT
Collagen, elastic and reticular
What cells are found in CT?
Fixed/resident cells:
* Fibroblasts (synthesise the ECM and collagen)
* Macrophages
* Adipocytes
* Mast cells
* undifferentiated cells
Transient cells:
* WBC (migrate to tissue from bloodsteam in response to damage/infection)
Give the 3 types of muscle tissue
- Skeletal muscle: Striated (highly ordered arrangement of contractile protiens acin and myosin)
- Cardiac muscle: Striated, branched (less highly ordered arrangement of contractile proteins)
- Smooth muscle: Non-striated, smooth (randomly ordered arrangement of contractile proteins
Where can each type of muscle tissue be found?
Skeletal: attaches to skeleton voluntary
Cardiac: found in heart involuntary
Smooth: found in organs involuntary
Regions of the neuron
Cell body (soma), dendrites, axon, terminals
Function of a nerve cell (neuron)
Plasma membrane:
- generation (nerve impulses/action potential)
- Conduction to farthest points of cell
Give an overview of glands
Mostly invaginations from epithelium into underlying CT = secretory epithelial cells. Can be one cell or multicellular
Give examples of unicellular and multicellular glands
Unicellular - goblet cells of trachea
Multicellular - exocrine acini of pancreas, follicles of thyroid gland
Define Exocrine glands
remain in contact with epithelium by ducts, secrete into lumen of tubes
Define endocrine glands
Loose contact with epithelium, ductless, secrete into blood vessels
How are exocrine glands classified
- Number of cells
- shape
- type of secretion
Exocrine glands - number of cells
Unicellular (goblet cells) or multicellular (acini)
Exocrine glands - shape
Simple (tubular and Acinar) or Compound (tubuloacinar)
Exocrine glands - type of secretion
- Mucous secreting glands: secretion rich in proteoglycans, with secretion + water giving mucus. Are pale staining, have peripheral flattened nuclei (e.g. mucous glands of trachea)
- Serous secreting glands: Watery, enzymes, with protien rich secretion. Are dark staining and rounded, with more central nuclei (e.g. exocrine part of pancreas).
3 mechanisma of exocrine secretion
- Merocrine secretion (diffuse): sweat glands
- Apocrine secretion (break off): mammary glands
3.Holocrine secretion (burst): sebaceous glands
What are myoepithelial cells
Have contractile functions and help in expelling secretions from the lumen of gland secretory units (acini)
Define connective tissue
Collective term for support cells and its associated ECM
What is the function of each connective tissue determined by
The types of support cells and the compostion of the ECM
What type of dense CT can form sheets
Dense regular
Goblet cells
type of intestinal mucosal epithelial cell (columnar epithelium), the primary function of goblet cells is to synthesize and secrete mucus
What else can lie in the ECM
Supporting cells, secreting the ground substance which forms the ECM. Specialised cells inc fibroblasts/adipocytes/osteoblasts.
Where are collagen fibres found?
mostly found in** connective tissue** (obviously) such as cartilage, bones, tendons, ligaments, and skin.
Where are elastic fibres found?
various joints, and in the fibrous perichondria of hyaline and fibrous cartilages - also in outer fibrous layer of periosteum
Where are reticular fibres found?
supporting mesh in soft tissues such as liver, bone marrow, and the tissues and organs of the lymphatic system.
Where can nerve cells be found
brain, spinal cord, and autonomic ganglia, and the cells of muscles and glands throughout the body.
Describe function of ECM, Fibres and cellular components of CT
- ECM - proveds scaffolding/attachements for neaby cells and allows communciation between cells
- Fibres - supports, protects, and holds tissues (e.g. bone/muscle/organs) in place
- Cellular - (fibroblasts) synthesise the collagen and ground substance of the extracellular matrix
glycosaminoglycan (GAG)
known as mucopolysaccharides, are negatively-charged polysaccharide compounds. They are composed of repeating disaccharide units that are present in every mammalian tissue.Their functions within the body are widespread and determined by their molecular structure
Histology of Tissues
See sheet
4 main classifications of Connective Tissue
- Loose - areolar, adipose
- Dense Regular
- Dense Irregular
- Specialised - cartilage, bone, blood
