Tissues Flashcards
epithelial tissue
covers exposed tissues
lines internal passageways and chambers
produces glandular secretions
layers of cells form linings, membranes and glands
layers
simple= single layer of cells
stratified= multiple layers
shape
squamous- flattened cell/ squashed
cuboidal- cube shaped, found in glands
columnar- long and narrow, longer than they are wide
transitional- cells that can change shape
epithelial cell structure
bottom= basal surface and basement membrane
contain organelles eg nucleus and mitochondria
cells connected by cell junctions
apical surface is open to external world eg lungs
specific adaptations on some cells eg microvilli/ cillia
simple squamous epithelia
eg linings of blood vessels and alveoli
provide smooth surface
reduces friction
help with absorption and secretion- shorter pathway for gases/ nutrients
stratified squamous epithelia
eg skin
lots of layers
provides physical protection against pathogens, abrasion and chemical attack
simple cuboidal epithelium
eg lining of ducts and glands
allows some protection
secretion of products into glands/ ducts and absorption
stratified cuboidal epithelium
lining of some glands eg sweat glands
protection, secretion and absorption
transitional epithelia
eg lining of urinary bladder
able to expand/ enlarge and recoil/shrink depending on contents of bladder
relaxed epithelium = empty bladder
stretched epithelium (shrunk so smaller) = full bladder
simple columnar epithelia
eg lining of stomach and intestine
have microvilli
tall cells so substances can pass through
protection, secretion, absorption
pseudostratified cilliated columnar epithelia
eg lining of nasal cavity, trachea and bronchi
partly layered as all cells are connected to basement membrane
cilliated with hair at the top
mucus producing cells which have cilia to clear/ move mucus
stratified columnar epithelia
eg small areas of the pharynx (mouth)
several layers of cells
provides protection- moves food around
exocrine glands
excrete out of the body eg sweat glands
can be simple or compound
simple- one duct
compound- multiple ducts
glandular secretion- merocrine
cells produce product in golgi appartus
vesicles containing product move up towards cell surface membrane
discharged from cell surface
product is released from exocrine cell by exocytosis
apocrine secretion
product accumalates in apical portion (top of cell) of cytoplasm
this portion of the cell is shed- cytoplasm breaks off, releasing vesicles with product
cells regrow and cytoplasm can be shed again
holocrine secretion
gland cell is destroyed in the process
cell division occurs at the base, cell becomes packed with secretory vesicles, cell increases in size and bursts; releasing the cytoplasmic contents
connective tissue
supports and protects
contains;
cells eg fibroblasts, macrophage, adipocytes
fibres eg collagen, elastic, reticular
ground substance eg blood, lymph, cartilage
develops from mesenchymal stem cells + can differentiate into different types of cell
loose connective tissue
provide padding/ connection between tissues
adipose- deep to the skin eg kidneys, buttocks
adipocytes (fat cells)
provides padding and cushion, insulates and stores energy
reticular- found in liver, kidney, spleen
reticular fibres- 3D branched to connect structures
provides supportive network
dense connective tissue
regular- lots of collagen fibres parallel to each other, creates rope like structure
provides firm attachment, can transfer forces, conducts pull of muscles
eg tendons and ligaments
irregular- collagen fibres in different directions to form a sheet/ layers of protection
provides strength to resist forces from different directions
eg in deep dermis + capsules of visceral organs
elastic- elastic fibres instead of collagen so stretchier than collagen, allows more expansion and contraction
stabilises and cushions shocks
eg elastic ligament
high proportion of protein fibres
connective tissue- cartilage
hyaline cartilage-
provides support with jelly like matrix with pits called lacunae with chondrocytes (cartilage cells)
and reinforced with collagen fibres
quite strong
eg between rib and sternum/ nose
elastic cartilage- elastic fibres instead of collagen
can tolerate distortion without damage, returns to original shape
matrix and lacunae is the same
eg ears
fibrocartilage- fibrous matrix and more collagen fibres
resists compression, prevents bone to bone contact
more strength
eg in joints
tissue membranes
all contain epithelial cells and a layer of connective tissue
mucous membrane-
outer epithelial layer, cells producing mucus
communicates with exterior of the body eg openings to lungs
Serous membrane- fluid on top/ surface which reduces friction, layer of squamous cells
lines body cavities
Cutaneous membrane (skin)- several layers
covers the body surface
Synovial membrane- lines joint cavities
produces synovial fluid
fasciae
superficial- layer underneath skin/ organs
adipose and areolar tissue
deep- tougher and stronger, dense connective tissue, surrounding organs
subserous fascia- connective tissue under serous membranes
maintains integrity of cavity
muscle tissue
Skeletal muscle tissue- fibres are striped/ striated
very large
under voluntary control- controlled via nerve (motor neuron)
Cardiac muscle tissue- smaller cells than skeletal, cells connected by intercalated discs- electrical activity
Involuntary control- controlled by pacemaker cells
Interconnected disks
Smooth muscle tissue- organs/ blood vessels, smaller, no stripes
pacesetter- electrical activity but slower
mostly under hormonal control
neural tissue
neuron cell- cell body, axon, dendrites connect with other neurones
neuroglia- supporting cells
maintain physical structure of tissues,
repair tissue network after injury
perform phagocytosis, provide nutrients to neurons, regulate the composition of intestinal fluid surrounding neurons
