Histology Flashcards
What does surface epithelia cover ?
covers or lines surfaces, cavities and tubes
lines the gall bladder
What does apical mean ?
faces the lumen of a tube or the external environment
What does basal mean?
attaches to the basement membrane
At what state are the cells?
Cells usually polarised
What are the functions of epithelial cells ?
Mechanical barrier(skin)
Chemical barrier(lining of stomach
Absorption(lining of intestine)
Secretion(salivary gland
Containment(lining of urinary bladder
Locomotion(oviduct)
Sensation(neuroepithelium: taste buds)
What type of epithelial layers are there ?
Simple
Stratified(+2 layers)
Pseudostratified(multiple layers)
What are microvilli?
finger like projections at the apical end of cells that increase surface area
What are microvilli also called?
Brush border
Cilia is important in…
Movement of water
What do keratin proteins do?
keratin protein on tissue surface, improves strength of the cells
What are goblet cells?
they have nucleus in the bottom and are single cell mucous glands
What do glandular epithelia produce?
they produce secretory products: sweat, hormones, mucous, enzymes etc.
How do endocrine cells secrete their products ?
They secrete the products into the blood and the hormones are distributed by the vascular system
What are endocrine cells also called?
ductless glands
How do exocrine cells secrete their products ?
secrete their products onto a surface through a duct
what are exocrine cells also called?
ducted glands
What types of connective tissue are there ?
Embryonic
soft
hard
special
What are the 3 basic cell shapes found in covering epithelia ?
Squamous(flattened)
Cuboidal(Cube)
Columnar(tall and thin)
What are the 3 main types of layer structure for epithelia
Simple
Stratified
Pseudostratified
How are hormones distributed?
Via the vascular system
What counts as soft connective tissue?
tendons
mesentery
storm of organs
dermis of the skin
What type of soft connective tissues are there?
Loose
Dense
Reticular
Adipose
How can you define loose connective tissue?
loosely packed fibres separated by ground substance
How can you define dense connective tissue?
densely packed bundles of collagen fibres
What is “dense regular” tissue?
fibres aligned (tendon)
What is “dense irregular” tissue?
fibre bundles running in many directions (ligament)
What are the 3 types of cartilage?
hyaline
elastic
fibrocartilage
What is hard connective tissue?
Bone and Cartilage
What are some characteristics from hard connective tissue?
strong
flexible
compressible
semi-rigid tissue
Describe the matrix of HCT?
semi-rigid nature of matrix comes from highly hydrated nature of the ground substance
What do we mean by HCT being avascular?
no venous system directly to the cells, the cells receive their nutrients from diffusion through their matrix
What is the most common type of cartilage?
Hyaline cartilage
What is made of hyaline cartilage?
articular surfaces
tracheal rings
costal cartilage
epiphyseal growth plate
What is made of the outer shell of dense cortical bone?
the shaft(diaphyses)
What can bone be defined as ?
outer shell of cortical bone- dense areas without cavities
What occupies the end of a bone and what is it called?
Epiphyses and it is made out of cancellous and trabecular bones
What do cancellous/trabecular bones have?
numerous interconnecting cavities
What do bones contain?
Osteocytes
What is bone ?
bone is a living tissue that is being penetrated by small canals(aversion canal) where blood vessels and nerves go through
What is bone being penetrated by?
small canals aka aversion canal
What is a small canal called as well?
aversion canal
What goes through the aversion canal?
blood vessels and nerves
What are considered cells?
Osteocytes
Osteoblasts
Osteoclasts
What is considered extracellular matrix?
Organic matrix: collagen and glycoprotein
Inorganic matrix: calcium and minerals
What are osteons?
formations characteristic to mature bone
What are Chondrocytes?
metabolically active cells that synthesise and turn over a large volume of ECM
What does the extracellular matrix consist of ?
fibres: collagen, reticular and elastic fibres
What is the ground substance made of?
it is a gel-like material found between cells in connective tissues
It does not have a specific shape and is made up of large , chain-like sugar molecules called glycosaminoglycans(GAGs)
What do glycosaminoglycans do?
they attach to protein cores to form bigger molecules called proteoglycans
What is the function of the ground substance ?
this substance helps tissues stay hydrated, supports cells and allows nutrients to pass through.
It also acts like a cushion, protecting tissues from pressure or damage.
What is the ground substance also been described as ?
“filler” that keeps tissues flexible, strong and healthy
What do fibroblasts do?
they produce and maintain the ECM
Where can adipose cells be found?
can be found and are scattered in many connective tissues but predominantly in adipose tissue
What are adipose cells?
fat cells
What are osteocytes?
bone cells
What are chondrocytes?
cells of cartilage
What is also considered as connective tissue?
Blood and lymph
What is blood considered as ?
fluid connective tissue
What do connective tissues consist of ?
extracellular matrix and cells
What do muscle cells do?
They generate force by contraction
Where can the contractile fibres be found in muscle tissue ?
can be found in the cytoplasm
Where are the contractile fibres usually found for other cells?
in the cytoskeleton
How does force happen?
it is the movement of actin fibres over myosin fibres
How does the movement of actin fibres over myosin fibres happen?
with the aid of accessory proteins
What 3 types of muscle tissue are there?
Smooth muscle
Cardiac muscle
Skeletal muscle
What is smooth muscle tissue?
involuntary/visceral muscle (muscle works itself)
What are some features of the smooth muscle ?
non-striated(non parallel)
simplest muscle tissue
not under conscious control
fibres are elongated and spindle shaped
How do the cells of a smooth muscle look like?
Non-striated, spindle shaped cell with a cigar-shaped nucleus, that lies in the centre of each fibre
How can smooth muscle tissue appear?
Longitudinal or transverse
What is cardiac tissue muscle ?
involuntary and striated muscle
What are some features of the cardiac muscle?
striated and has a single nucleus at the centre of fibre.
has intercalated discs that contain intracellular junctions for stability
Where can smooth muscle tissue be found?
in organs
What is special about the striations in cardiac muscle?
they are less prominent in comparison to skeletal muscles
What is cardiac mostly involved in?
It forms major part of the walls of the heart chambers and origins of great vessels
Fibres are…
much shorter than striated muscles and form a complex network
Where is the nucleus for cardiac muscle located ?
In the centre of the fibre
What is skeletal muscle tissue?
voluntary, striated multinucleated
What is the special thing about skeletal muscles ?
it has muscles that respond to conscious control
What is the structure of the skeletal muscle cell?
it has a big multinucleate cylindrical cell located at the periphery of cell
What do the fibres of skeletal muscles have?
each fibre has many elongated nuclei
Where are the nuclei in the skeletal muscle located?
located at the periphery of the cell, internal to the sarcolemma
What is nervous tissue?
consists of neurons and their supporting glial cells
What does nervous tissue do?
serves as a control function and allows rapid communication between cells
What are neurons used for?
to conduct impulses
What parts do a neuron have?
a cell body and a cytoplasmic process(dendrite and axon)
What is meant by cytoplasmic process in neuron?
dendrites at one end and axon at the other end
What do Schwann cells do?
produce myelin and support axons
What do oligodendrocytes do?
they produce myelin in brain and spinal cord
What does Microglia do?
provides immune surveillance
What do astrocytes do?
provide support in ion transport and induce blood brain barrier
What types of neurons are there?
Multipolar neuron
Bipolar neuron
Pseudo-unipolar neuron
What features do multipolar neurons have ?
multiple dendrites and one axon
What features do bipolar neurons have?
one dendrite and one axon
What features do pseudo-unipolar neurons have?
one axon and
a peripheral+ short process
What neurons do sensory pathways have?
bipolar and pseudo-unipolar neurons
What are neurons surrounded by?
by connective tissue coat
What are neurons surrounded by in the CNS
meninges
What are neurons surrounded by in the PNS?
Epineurium
What are the 4 basic types of tissues?
Epithelia
Connective
Muscle
Nervous
What are the 3 main salivary glands?
Parotid
Submandibular
Sublingual
What 3 parts is the mucosa made of ?
Epithelium(sits on basal lamina)
Lamina Propria(loose connective tissue)
Muscularis Mucosae(thin layer of smooth muscle)
What are the 4 major layers in the GI tract?
Mucosa
Submucosa
Muscularis
Serosa
What is the submucosa made out of?
loose connective tissue
outer layer of connective tissue
- Serosa: suspends digestive tract
- Adventitia: attaches to other organs
What is the muscular external made out of?
2 thick layers of thick muscle
What 4 different variations of mucosa are there?
Protective mucosa
Absorptive mucosa
Secretory mucosa
Protective and absorptive mucosa
Describe protective mucosa?
non-keratinised stratified squamous epithelium
Where can protective mucosa be found?
Oral cavity
Pharynx
Oesophagus
Anal canal
Describe absorptive mucosa ?
simple columnar epithelium with villi and tubular glands
Where can absorptive mucosa be found ?
small intestine
Describe the secretory mucosa?
simple columnar epithelium with extensive tubular glands
Where can secretory mucosa be found ?
Stomach
Describe Protective and absorptive mucosa?
Simple columnar epithelium with tubular glands
Where can protective and absorptive mucosa be found ?
large intestine
What is the nervous system of the GI tract also called ?
Enteric nervous system(ENS)
What are hepatic lobules?
small divisions of the liver
What vessels are part of the Liver?
bile duct
branch of hepatic artery
portal vein
Central vein
What two types of glands are there in the pancreas?
Exocrine and Endocrine
What does the exocrine gland of pancreas do?
produce digestive juices, proteases and lipases
What does the endocrine of pancreas do?
Has islets of langerhans cells and produces insulin and glucagon
What components are in the respiratory system?
Bronchi
Bronchioles
Alveoli
Upper respiratory tract
Trachea
Bronchial tree
Lungs
What happens at the alveoli?
Site for gas exchange
What are the main constituents in the urinary system?
Renal cortex
Renal medulla
Ureter
What does the medulla consist of?
Loop of henle
Collecting duct
What does the Cortex consist of?
Renal corpuscle
Proximal convoluted tubule(PCT)
Distal Convoluted tubule(DCT)
Nephron(main functional unit)
What does the PCT do?
absorbs fluids
What does the DCT do?
does NOT absorb fluids
What are the 3 main blood vessels?
Arteries
Veins
Capillaries
What are the 3 layers of a blood vessel?
Tunica intima(Endothelium)
Tunica media(smooth muscle)
Tunica externa(Connective tissue)
