Tissues Flashcards
Blood vessels in tissues
Not all have them
Cartilage, cornea, lens, skins epithelial layer don’t have blood vessels
Tissue definition
Groups of cells similar in structure that work together to perform a or many functions
Four types:
Epithelial (forms boundaries between different environment, secretes, absorbed, more)
Muscle
Connective
Nervous
Epithelial tissue/epithelium
Forms sheets
There is a Apical (free, either facing exterior of facing a cavity, contains microvilli/cilia) surface and a basal surface, which sits on basal lamina
Avascular (no blood vessels)
Regenerate easily (high metabolism)
In skin, ventral body cavities, surface lining of internal organs, innermost lining of ducts, vessels, tubes, glands
Main function: if thick, it’s often for protection
If thin, often for absorption, filtration, excretion and secretion
Also sensory reception’
Basal side always sitting on connective tissues,
Sheets of epithelial cells
Bound by :
Tight junctions
Desmosomes, look like giant Velcro
Basement membrane
Made of collagen, split into basal lamina and reticular fibers (closer to connective tissues)
Reinforces epithelial sheet
Resist stretching and tearing
Defines epithelial boundary
Below it is connective tissue
How do epithelial cells obtain nutrients and get rid of waste
Through diffusion
Classification of epithelium
By the number of cell layers:
Simple: single layer, usually not for protection
Stratified: many layers, protection
By cell shape:
Squamous: flattened
Cuboidal: cube shaped
Columnar: long column like
Simple squamous
lines the heart, air sacs of lungs, capillaries, serous membranes
For transport
Sub categories:
Endothelium: lining blood vessels, lymphatic vessels and heat chambers
Mesothelium: serous membrane in the ventral body cavity
Simple cuboidal
Walls of Kidneys tubules
Glands and ducts
Surface of ovaries
Absorpotion and secretion
Simple columnar
Some contain goblet cells that secret mucus
Some have microvilli of cilia on apicale side
Lines digestive tract
Uterine tubes
Bronchi
Secretion and absorbtion
Pseudostratified columnar
Single layer, because nuclei not lined up, but looks like many layers
All cells rest on basement membrane
Trachea (ciliated)
Vas deferens (non ciliated)
Secretion and absorbtion
Stratified squamous
Squamous at the apical surface, deep layers don’t need to be squamous
Skin
Moist linings (mouth and esophagus)
Protection in areas where friction is common
Part of it is dead keratinized cells, water proof
The more friction (ex palm) then keratinized layer thicker
Stratified cuboidal and columnar
Rare
Typically 2 layers of cuboidal
Ducts of large glands (sweat glads esophageal glands)
Protection
Transitional epithelium
Cell shape depends on amount of stretching
Basal levels cuboidal or columnar
Lining hollow urinary system organs
Becomes flatter as it stretches
Glandular epithelia (glands)
One or more cells that makes and secrets a fluid
Classified by:
Site of product release: endocrine (internally secreting, ex hormones)
Exocrine (externally secreting)
Number of cells forming gland: unicellular (respiratory and intestinal tracts, ex goblet cells which produces mucus) or multicellular (salivary)
Nervous tissue
Main control
Found in brain, spinal cord and nerves
Types:
Neuron: electrically active
Neuroglia: support protect and nourish neuron
Muscle tissue
Contracts to produce movement (voluntary muscle movement, propulsion in the gastro+p-intestinal tract, pumping blood in heart)
3 types of muscle:
Skeletal: muscle that move your bones, conscious control over these. Long cylindrical cells, multinucleate (lines called striations)
Cardiac: muscle of the heart, uninucleate, branched. Darker stained lines called intercalated discs, (when a side contracts, send calcium to the next side so all is synced)
Smooth: found in majority of visceral organs, smooth and pink, will never be exposed to a cavity (no epical side),
Connective tissue
Most abundant tissue
Diverse functions
Composed of:
Cells
Extracellular matrix composed of ground substances (H2O, cell adhesion molecules, proteoglycan) and protein fibers (collagen, elastic)
5 types of connective tissue:
Bone
Cartilage
Dense connective tissue
Loose connective tissue
Blood
Cells of connective tissue:
Blasts: immature, responsible for repair and growth, Mitotic cells
Cytes: mature, less active, responsible for maintenance of health
Extracellular matrix (ecm)
Medium through which solutes diffuse between blood capillaries and cells
Supports cell so can bear weight and tension
Elastic fibers
Collagen fibers
Fibroblast nuclei
Has accessory cells: fat cells, white blood cells, macrophage
Bone
Osseous tissue
Avascular
Collagen
Composed of :
Osteocytes, sitting in lacunae (cavities)
Hard matrix of calcium salts
Lots of Collagen fibers
Function: protect and support body
Bone human skeleton
Axial skeleton
Head & trunk:
• Skull
• Ribcage
• Vertebral column • Hyoid bone
Appendicular skeleton
Appendages:
• Scapula
• Clavicle
• Arms
• Legs
• Pelvic girdle
• Hands
• Feet
Cartilage
Less hard and more flexible than bone
Chondrocyte: major cell type
Collagen, elastic, sometimes fibres
3 types: (ecm is what’s variable between them)
Hyaline cartilage:
Fibrocartilage:
Elastic cartilage
Hyaline cartilage
most abundant,
coats the ends of your long bones so bones don’t grind,
Found in:
trachea
attaches ribs to breastbone (sternum),
end of long bones,
all of fetal skeleton before birth,
epiphyseal plate in long bones (will become thinner as you grow older)
Elastic cartilage
More flexible (ex ears)
Maintains shape while allowing flexibility
Found in epiglottis, external ear
