1.2 Tissues Flashcards
What are the 4 basic tissue types?
Nervous
Muscle
Epithelial
Connective
What is connective tissue composed of
Made from cells surrounded by an extracellular matrix. The extracellular matrix is made of ground substance and protein fibres.
How can connective tissue vary in terms of packing
It can be loosely packed (not many cells and lots of ECM) or tightly packed (lots of cells and not much ECM)
What are the 3 types of protein fibre in the ECM of connective tissue
-collagen
-reticular
-elastic
What are the properties of collagen fibres in ECM
-have variable thickness
-usually runs parallel
-makes dense connective tissue
What are the properties of reticular fibres in ECM
-are a type of collagen with dark fibrils
-has a loose network that allows for molecular movement
What are the properties of elastic fibres in ECM
-gives recoil
-layout varies
-is in distensible/contractile organs like lungs
Give 4 functions of connective tissue
-structural support
-medium for exchange
-storage
-defence and repair
Give an example of CT used for structural support
bones, ligaments, cartilage, tendons (all dense regular collagenous)
Give an example of CT used for a medium of exchange
blood or the CT underlying the epithelium
Give an example of CT used for storage
adipose (storing vitamins and fats) or bone (storing calcium and phosphate)
Give an example of CT used for defence and repair
blood (WBCs) or blast cells
What is the difference between fixed and transient connective tissue
Fixed connective tissue stays in place but transient moves areas of the body in response to stimuli
Give some examples of fixed connective tissue
cartilage, tendons, bones, mast cells, pericytes, adipocytes
Give some examples of transient connective tissue
leukocytes, monocytes, phagocytes, neutrophils, lymphocytes
Give the properties of epithelial tissue
-avascular
-highly cellular sheet that covers surfaces
-one nucleus
-come from all 3 germ layers
-have a free apical surface and a basal surface, bot of which are different which makes the cells polar
-cells are bound to each other by junctions
-cells are regenerative
Give 4 functions of epithelial tissue
-protection
-secretion
-absorption
-sensory detection
Give an example of epithelial tissue used for protection
highly layered stratified squamous (often keratinzed) in skin and oesophagus
Give an example of epithelial tissue used for secretion
stratified cuboidal for sweat and salivary glands
Give an example of epithelial tissue used for absorption
in the intestine, simple columnar epithelial has microvilli to increase surface area
Give an example of epithelial tissue used for sensory detection
olfactory epithelium in the nasal cavity is pseudostratified columnar
What is nervous tissue composed of
Neurons (which are the functional unit) and glial cells
What are the 3 types of muscle tissue
smooth, cardiac and skeletal
Give some general properties of muscle tissue
-heavy and darker due to high protein content
-excitable, contractile, elastic and extensible
Which of the 4 tissue types are excitable
Nervous and Muscle
What stimuli can excite nervous and muscle tissue
neurotransmitters, hormones ,drugs, mechanical stimuli and external electrical impulses
Describe the fixation stage in light microscopy
A neutral buffer is used to inactivate some enzymes so to prevent decay and keep the tissue life like
Describe the dehydration and clearing stage in light microscopy
Removing water from the sample so it is easier to handle
Describe the embedding stage in light microscopy
When liquid paraffin is injected into the sample then left to dry out, this hardens the sample
Describe the sectioning stage of light microscopy
The sample is thinly sliced (15-50 micron length) and mounted on the slide
What is hematoxylin and eosin staining
Hematoxylin stains the nucleus purple and eosin stains the cytoplasm pink/red
What is silver staining
Targets proteins and nucleotides, turning them brown/orange
What is masson trichome staining
A series of 3 stains that turns collagen blue/green, muscle fibres red and nuclei black
What is periodic acid schiff staining
Stains polysaccharides red and purple
What is wright and giemsa staining
Used on blood smears, stains RBCs pink/red, WBC nuclei purple and platelets light blue
What is alcian blue staining
Stains acidic mucopolysaccharides (commonly found in in goblet cells, mucins, connective tissue tumours and cartilage) blue
