Tissues Flashcards
What are the 4 types of tissue?
Epithelial
Muscular
Connective
Nervous
What is the epithelium?
The tissue that covers the surfaces of the body and hollow organs, regulates exchange between external and internal environments, and manufactures and excretes substances
What are the five functional types of epithelial tissue?
Exchange Transport Ciliated Protective Secretory
Where are exchange epithelia found?
Lungs and lining of blood vessels
What are the main structural features of exchange epithelia?
Simple squamous - very thin
Pores between cells to permit the passage of molecules
Where are transport epithelia found?
Intestines, kidneys and some exocrine glands
What are the main structural features of transport epithelia?
Simple columnar/cuboidal
Tight junctions between adjacent cells to prevent ‘leakage’ - meaning that molecules (nutrients) must pass from one side of the cell, to the other
Can form structures such as villi, with individual cells having microvilli
Where would you find ciliated epithelia?
Nose
Trachea
Upper airways
Female reproductive tract
What are the main structural features of ciliated epithelia?
Simple columnar/cuboidal
Have cilia on one side of them funnily enough
Where would you find protective epithelia?
Skin and the lining of some cavities such as the mouth
What are the main structural features of protective epithelia?
Stratified squamous
Cells become more flat at the top and are rounder at the bottom
Adjacent cells connected tightly by a many desmosomes
Where would you find secretory epithelia?
Glands
What are the main structural features of secretory epithelia?
Can be single or multicellular
Columnar or polygonal in shape
Structural features depend on type of gland
What is the difference between simple and stratified epithelia?
Simple - single layer of cells
Stratified - multicellular layer
What are the types of simple epithelia?
Squamous
Cuboidal
Columnar
What are the types of stratified epithelia?
Squamous
Cuboidal
Columnar
Transitional
(+ pseudostratified but its kinda half way between simple and stratified)
Where would you find stratified transitional epithelia?
Urinary bladder
What are desmosomes?
Adhering junctions that hold epithelial cells together
Attached to the cell cytoskeleton
What membrane protein is used to make up desmosomes?
Cadherin
What functional type of epithelial tissue has the most desmosomes?
Protective
What are hemi-desmosomes?
Adhering junctions that attach epithelial cells to the basal lamina of the basement membrane
Cell-ECM
What are tight junctions?
Cell-Cell junction that prevents leakage of molecules between joined cells
What functional type of epithelial tissue uses a large amount of tight junctions?
Transport epithelia
What membrane proteins are used to make tight junctions?
Claudin
Occludin
What are gap junctions?
Communicating junctions
Cell-Cell
What membrane protein is used to make up gap junctions?
Connexin
What is the basement membrane?
Layer of extracellular matrix
Made from collagen and laminin filament embedded in proteoglycans
What are the 2 layers of the basement membrane?
Basal lamina & reticular lamina
What are the 2 types of glands, and their basic difference?
Exocrine and endocrine
Exocrine - into tubes to the extracellular environment
Endocrine - into the blood
What do exocrine glands excrete?
Mucous or serous secretions
What are mucous secretions?
Mucous is a thick liquid, rich is proteoglycans and glycoproteins
What are serous secretions?
Watery secretions, such as sweat, tears and digestive enzymes
What are some examples of exocrine glands?
Sweat glands Salivary glands Mammary glands Liver Pancreas Mucous glands in the trachea etc
What are goblet cells?
Single celled mucous producing exocrine glands
What do endocrine glands produce?
Hormones or proteinaceous secretions
What are examples of endocrine glands?
Thyroid gland
Pituitary gland
Pancreas (it is both exocrine and endocrine)
Gonads
What are the potential effects of a disfunctional pituitary gland?
Over production or under production of growth hormone
Over production - pituitary gigantism
Under production - pituitary dwarfism
What are the potential effects of a Chlamydia trachomatus infection?
Damage to exocrine gland in uterine tube
Mucous becomes overly thick
Ovum and sperm can’t move so the sufferer is infertile
What two types of epithelial cells are found in the liver?
Hepatocytes and support epithelial cells
Hepatocytes have multiple functions but act as secretory cells
Support cells line the blood vessels and the bile duct, to protect the liver from the bile
(Theres also stuff on the kidney we need to know but i cant be fucked typing it)
What are myoepithelial cells?
Cells associated with salivary glands that contain contractile proteins
These contract and force out the secretion, which is useful when it is thick and sticky
What are the different types of connective tissue
For each type, state where you’d find it
(unless it’s really obvious)
theres 7
Loose - skin, around blood vessels, under epithelia
Dense irregular - Muscles & nerve sheaths
Dense regular - Tendons & ligaments
Adipose
Cartilage
Bone
Blood
What is the ground substance?
The extracellular matrix of connective tissue
How does the ground substance vary between different types of connective tissue
Can be liquid: in blood etc
Can be gel-like: in loose connective tissue
Can be solid, hard: in bone, for example
What cell type is most abundant in both Loose, dense regular and dense irregular connective tissue?
Fibroblasts - collagen producing cells
Describe the basic structure of loose connective tissue
Collagen and elastin fibres in irregular arrangement
Fibroblasts producing the collagen fibres
Macrophages and other WBC’s
Blood vessels
Adipocytes
How are collagen fibres arranged in Dense regular connective tissue?
Bundles in parallel to each other
