anat2011 histology notes - studentvip
TRANSCRIPT
ANAT2011 Histology Notes
Module 1: How to Speak Histology
• Histology Ultrastrucutre of cells .............................................................................. 2
Module 2: Nervous System
• Epithelial Tissue ..................................................................................................... 7
• Neural Tissue ....................................................................................................... 13
Module 3: Sniff, swallow, speak!
• Histology of Nose, Mouth and Salivary Glands ........................................................ 22
Module 4: Just Breathe
• Histology of Heart and Vessels .............................................................................. 35
Module 5: Who are the Great 8?
• Histology of Respiratory System ............................................................................ 45
Module 6: No Guts, No Glory
• Histology of Upper GIT ......................................................................................... 52
• Histology of Lower GIT .......................................................................................... 64
Module 7: Toilet Break
• Histology of Renal System ...................................................................................... 72
Module 8: Sex and Multiplication
• Histology of Male Reproductive System ................................................................. 86
• Histology of Female Reproductive System .............................................................. 97
Module 9: Muscoskeletal System
• Histology of Smooth Muscle and Connective Tissue .............................................. 111
• Histology of Bone Cartilage and Joints.................................................................. 118
Module 1 Histology Ultrastructure of cells Cytoplasm
• Contains organelles (membrane and non-membrane bound ones), inclusions (small, insoluble particles such as glycogen, lipid droplets) and cytosol (water, salts, organic molecules, soluble proteins)
Plasma membrane
• Lipid bilayer structure • 9nm wide • selectively permeable • contains pumps, channels, receptors • hydrophilic heads face outside and hydrophobic tails face each other on inside
Nucleus
• nucleus of non-dividing cells contain chromatin, and dividing cells have chromosomes • chromatin=DNA + histones (proteins) packaged together, their main function is to
package DNA into a compact form • 2 types of chromatin
o euchromatin-more active, less compact, lighter o heterochromatin-less active, more compact, darker
• Cytoskeleton
• cytoskeleton is the cells internal framework of filaments and tubules • its function is structural support and is important for intracellular movement of
organelles • 2 main components (that we need to know)-microtubules, microfilaments, • microtubules
o function ▪ intracellular transport ▪ maintain cell shape ▪ cilia movement ▪ chromosome arrangement
o they continually form and disassemble o structure
▪ tubulin protein ▪ hollow cylinders ▪ 22nm diameter
▪ 5nm thick walls o things that disrupt them are drugs, reduced temperature and increased
hydrostatic temperature
o o
o • Microfilaments
o Structure ▪ Made up of actin ▪ Flexible ▪ 6nm diameter
o much thinner than microtubules o function
▪ microvilli structure ▪ extension of cell processes ▪ provide support to cells
o Mitochondria
• generate ATP via oxidative phosphorylation, citric acid cycle, ß-oxidation of fatty acids • initiate apoptosis (controlled cell death)
• Rough endoplasmic reticulum (RER)
• function is protein synthesis via transcription and translation thus has many ribosomes present
• often next to golgi apparatus
• o made up of cisterna (flat sheets of membrane) which have ribosomes on them
Smooth ER
• function is lipid and steroid metabolism, synthesis of steroids, detoxification, membrane formation, calcium isolation
• also have cisternae but lack ribosomes • often glycogen surrounding
• Golgi apparatus
• stacked, flattened membrane bound cisternae with small vesicles budding off terminal cisternae
• function is to package and modify proteins from RER, receives proteins via incoming transport vesicles at cis face
• trans face is output of secretory vesicle end
• Lysosomes
• membrane bound • formed from golgi • contain digestive/hydrolytic enzymes such as protease (breaks down proteins) and
lipase (breaks down fat) • components to be digested are in endosome, hydrolytic enzymes are synthesised in RER,
pass to golgi via transport vesicles and then are added to endosomes to form lysosomes • digested material can be re-used by cell • undigested material forms residual body
Module 2 Histology-Epithelial tissue General
• covers inner and outer surfaces of body • cells connected via junctions • no blood vessels • attached to a basement membrane • usually has ability to constantly shed and replace
Types of epithelium
• squamous→ width>height
o ▪ these show stratified squamous epithelium
• cuboidal→ width=height
o • columnar→ height>width
o • pseudostratified (pseudostra)→ appears stratified but all cells rest on basement
membrane
o • transitional→ability to expand and contract
o usually dome shaped cells at apical surface o line urinary organs→bladder and ureter
o Mucosa
• consists of epithelial cells overlying connective tissue (CT) • covers internal surfaces of organs and vessels
Serosa
• consists of mesothelium (simple squamous epithelium) overlying CT • covers outer surfaces of organs and lines body cavities • mesothelium lines major body cavities like lung and heart cavity
Endothelium • simple squamous epithelium that lines blood vessels
• Apical surface specialisations
• microvilli o shortest of specialisations o contain actin filaments o increase surface area for absorption
o • cilia
o made up of microtubule doublets plus dynein protein o arranged in 9+2 pattern known as axoneme
▪ o longest of specialisations o often are motile and are to move substance along in lumen
o
• stereocilia o didn’t mention much, medium sized o basically longer microvilli
Lateral specialisations
• only really seen in electron micrograph • lateral specialisations referred to as terminal bar or junctional complex and run along
lateral surface of epithelial cells but only really towards apical region i.e. don’t run down that deep
• junctional complex always includes zonula occludens and adherens and may include the others but not always
• components of junctional complex (photos below) usually from superior to inferior are: o zonula occludens/tight junction
▪ provides adhesion and allows selective movement of ions and water through intercellular space
▪ • yellow are proteins which have actin filaments attached, these
proteins give it a fuzzy dark appearance in electron microscope • also note that the two cell membranes don’t fuse, they just get
very close o zonula adherens/ adherens junction/ intermediate junction
▪ much stronger adhesion than occludens, but don’t appear as dark in electron microscope
▪ doesn’t allow any substances through ▪ reinforces against mechanical stress
▪ ▪ again plasma membranes of cells don’t fuse and leave an intercellular
space o desmosomes aka macula adherens
▪ like zipper, very hard to rip apart ▪ very similar to adherens ▪ have intermediate filaments coming off protein zipper, can often see
filaments in electron microscope
▪ black region running down centre is protein zipper, proteins are intercollating here
▪ o gap junctions/communicating junctions
▪ 6 specific proteins channels which run through intracellular space and can open or close to allow stuff through
▪ hard to recognise, probably wont be asked to identify
▪
• also have lateral interdigitations
o run all the way down lateral wall and are like puzzles interlocking, offer further adherence to adjacent cells
Basement membrane
• epithelium is anchored to basement membrane • produced by fibroblasts • can influence differentiation, regeneration, shape of epithelial cells • filtration barrier via ionic charge e.g. if epithelial cells were absorbing a substance,
basement membrane can selectively transport it to vessels • allows underlying immune cells to migrate across it towards lumen for immune
response • epithelial cells are attached to basement membrane via hemi desmosomes
o • also compartmentalises underlying CT and overlying epithelial tissue