Tissues 1&2 Flashcards
Name some primary functions of epithelial tissue
- secretion
- absorption
- protects
- avoids dehydration
What defines the function in epithelial cells?
The cells
Name a secondary function of epithelial tissue
Forms glands
What determines the functions of connective tissue
ECM proteins
Give some examples of connective tissue
- liquid Blood
- solid bone
- Adipose ( fat cells and adipose cells)
What is muscle tissues function?
Causes force to be generated and moves things
Describe the composition of a muscle cell
Long, thin cells with actin, myosin and mitochondria
Name some other functions of muscle tissue
Close down spaces eg bladder
Operates blood pressure
Name the 3 main types of muscle
Smooth, skeletal and cardiac
What does nervous tissue do?
Integrate information around the body allowing emotion, memory etc.
What is grey matter?
Cell bodies of neurons
What is white matter?
Myelin (glial cells)
3 ways epithelial tissue maintains coverage of surfaces
no contact inhibition
cell - cell junctions
cell-ECM junction
Name the 3 cell-cell junctions and a brief summary
- desmosome (strong, intermediate filaments)
- tight junction ( waterproof)
- Gap junction ( allow movement of ions)
Hemidesmosomes
Basement membrane - intermediate filaments
Basement membrane
Basal lamina and apical lamina
Do all epithelium cells sit on a basement membrane?
Yes
What happens when there is a defective basal lamina?
Skin flakes off
What is the function of thick epithelial tissue
Wear and tear eg skin
What Is the function of thin epithelial tissue?
Diffusion eg capillaries
Cilia
Fingerlike projections from apical side
9+2 arrangement
Movement
Microvilli
Increase surface area - short and thin
Supported by actin microfilaments
Why are skin stem cells used in MND patients?
Good regenerative powers to create motor neurons
Simple epithelium tissue
- squamous - pavelike, diffusion
- cuboidal - secretion
- columnar - secretion
Stratified epithelium
- squamous, cuboidal, columnar - salivary gland
- transitional - spherical, protective, urethra
Pseudostratified
Look stratified but not as nuclei at different levels eg trachea
What are glands?
Collection of secretory epithelial cells
Exocrine
Spill out into gut, liver secretes through tubes
Endocrine
Hormones into blood, no tubes
Development of exocrine glands
Proliferation of cells still in contact and invaginate and secretions out of a tube
Development of endocrine glands
Loose contact with the surface and blood vessels grow
Simple exocrine
Tubular - long thin straight watery
acinar - grape, secrete mucous
Compound exocrine
Tubuloacinar - salivary glands
Mucous
Secretion rich in proteoglycans
Proteins with loads of sugar branches to absorb water
Serous glands
Protein rich watery secretions eg exocrine/endocrine pancreas
What does the exocrine pancreas release?
Digestive enzymes - blockage leads to pancreatitis
What does the endocrine pancreas release?
Insulin - packaged in vesicles and released when needed
Myoepithelial cells
Specialised epithelial cells which turn muscle cells that contract to help secretion of mucous
Where are the nuclei in endocrine glands?
In base of cells towards the middle and excretion areas toward blood vessels
What are lipid droplets the precursors for?
Steroid hormones from adrenal glands
Where us all of the epithelial compartment work done by the liver?
Parenchyma on hepatocytes which arranged in rows to maximise blood flow to cells
What do support cells do?
Accumulate and go to digestive system to line bile ducts and blood vessels
What do the kidneys do? epithelial component
Filter urine and is a big exocrine gland
What does the cortex contain?
Nephrons and contains capsules
Medulla of kidney
Made of collecting ducts for absorption and secretion
What is the prox tube?
Kidneys secrete everything then take back in what they need through the prox tube to take from urine =>bladder
What receives toxic urine?
Renal pelvis
What do nephrons do?
Filter blood
Partial absorption
Release urine
5 abnormal functions of epithelial cells
Over proliferation + over secretion
under proliferation + under secretion
Loss of cilia/ ciliary beat ==> smoking
Abnormal functions of pituitary gland
Pituitary - prone to cancers
HGH - dwarfism/gigantism
Abnormal function of uterine tube gland
Mucous gland - chlamydia
Thick mucus and egg cannot move - sterile
Is connective tissue cellular?
No made from cells but not cells that secrete
Fluid, mineral deposits or fibrous proteins
Examples of connective tissue
blood/bone marrow - loose, cartilage
mucous
reticular (collagen)
Adipose tissue - fat
Adipose
Intestine fat in mesentery and found in bone marrow, beneath skin
Contains many small blood vessels and lipid droplets make membrane
ECM components
Fibres ==> insoluble collagen in tendons and skin
ground substance eg dissolved albumin
Tissue fluid
Collagen fibres
30% body weight, rope like and strong
type 1 - tendons
type 3 - reticulin
type 4 - underneath epithelial
Reticulin fibres
Force blood around lymph
Elastic fibres
Won’t stretch but bend around aorta
Protein elastin
Fibroblast ==>?
Collagen
Ground substance
Proteoglycans, glycoproteins and hyaluronic acid
Loose connective tissue - permanent cells
Fibroblasts, undifferentiated mesenchymal cells, adipocyte, mast cells and macrophages
Loose connective tissue - transient cells
RBC + WBC - pierce into connective loose tissue and move to lymph looking for bacteria
Dense regular connective tissue
Tendon
Thick collagen fibroblast
Strength in one direction
Dense irregular connective tissue
Sebaceous gland - skin
Irregular and convoluted
Abnormal function of Blood/bone marrow
Leukaemia
Abnormal function of loose/dense
Weak collagen and skin pulls off
Abnormal function of cartilage
Tear - split collagen
Abnormal function of Bone
Osteoporosis - minerals become thin and bone becomes brittle
