Histology Flashcards
Explain the 3 layers that make up blood vessels
Tunica intima (squamous epithelial cells) Tunica media (smooth muscle) Tunica adventitia (supportive connective tissue)
What seperates the tunica media from the tunica adventitia
external elastic membrane
What seperates the tunica media from the tunica intima
internal elastic membrane
Explain what elastic arteries are
- large arteries e.g. aorta
- contain sheets of elastic fibres
- provide elastic recoil
Explain the histology of arterioles
- contain 1 or 2 layers of smooth muscle
- almost no tunica adventitia
Explain the histology of capillaries
- endothelial cells and basal lamina
- may contain pericytes
What are pericytes
connective tissue with contractile properties
What are the 3 types of capillaries
- continous (muscle, connective tissue)
- fenestrated (small pores - gut, endocrine glands)
- discountious (large gaps - liver, spleen)
What are the 3 layers of the heart
- endocardium
- myocardium
- epicardium
Where are intercalated disks found and what is their purpose
- found in the contractile cardiac muscle in the myocardium
- allows the spread of electrical activity
Two types of pericardium
- fibrous (fibrocollagenous connective tissue)
- serous (simple squamous epithemlium)
Serous lies in the inner surface of the fibrous pericardium
What lie inbetween the 2 pericardiums?
pericardial cavity
small amount of fluid for lubrication
Explain the histology of the heart valves
- outer endothelial layer with basal lamina
- layer of collagen and elastin fibres
- lamina fibrosa lies on the fibrous skeleton
- chordae tendineae (fibre like)
What would pacemaker cells look like down the microscope
- pale in colour
- smaller than contractile myocytes
What would purkinnje fibres look like down the microscope?
- paler in colour
- larger than cardiac muscle cells
- found in subendocardial layer
What are the 5 main components found in all Eukaryotic Cells?
- an outer membrane
- inner cytosol
- cytoskeleton
- membrane bound organelles
- inclusions
What are inclusions
- other structures within the cytoplasm which may or may not be bound by a membrane
What is the cytosol?
solution of proteins, electrolytes and carbohydrates
it has a fluid/gel-like properties
What is the plasmalemma?
- separates the cytoplasm from the outside environment
What is the plasmalemma composed of?
- amphiphatic phospholipids
- hydrophilic head
- hydrophobic (fatty acid) chains
- may contain integral proteins
What are 2 main differences between inclusions and organelles?
- inclusions are non-living, may or may not be membrane bound
- organelles are living and are membrane bound
What is the job of the rough endoplasmic reticulum?
- protein synthesis
- studded with ribosomes
What is the job of the smooth endoplasmic reticulum?
- cholesterol and lipid synthesis
What are the 3 main classes of filaments in the cytoskeleton? and what are their sizes?
- microfilaments (7um)
- intermediate filaments (>10um)
- microtubules (25um)
Explain microfilaments
- 7um
- composed of protein actin
- assemble and disassemble –> very dynamic
Explain intermediate filaments
- > 10um
- bind intracellular elements together and to the plasmalemma
Explain microtubules
- hollow tubule composed of alpha and beta tubulin
- originate from centrosome
- include stabilising proteins (MAPS)
- they are polar
What are kinesin and dynein?
what way do they move?
They are both ATPases that attach to microtubules
- Kinein moves to cell periphery
- Dynein moves to cell centre (dynein comes home for dinner)
Name given to the gap between the outer and inner nuclear membrane?
- perinuclear cistern
Euchromatin
- DNA that is more dipsersed
- actively undergoing transcription
Heterochromatin
- DNA that is highly condenses
- not undergoing transcription
What is the endoplasmic reticulum (ER) and what are the 2 categories?
- forms a network of interconnecting membrane bound compartments in the cell
- SER
- RER
What is the Golgi complex composed of?
- flattened, membrane bound cisternae
What is the role of the Golgi complex?
- modification and packaging of macromolecules that arrive from SER and RER
What is the Cristae?
- Innerfolds of the mitochondrial membrane
What are intracellular junctions?
- specialised membrane structures which link individual cells together into a functional unit
What are the 3 types of intracellular junctions?
- occluding
- anchoring
- communicating
What do occluding junctions do?
- join cells together to create a diffusion barrier
What do anchoring junctions do?
- provide mechanical strength
What do communicating junctions do?
- allow movement of molecules between cells
What is a junctional complex?
- close association of several types of junctions found in certain epithelial tissues
Another name for occluding junctions?
- Tight junctions
Another name for anchoring junctions?
- desmosomes
Another name for communicating junctions?
- gap junctions
Explain how a tissue sample is made?
- tissue fixed
- thinly sliced
- impregnated with wax
- dehydrated, hot solvent
- cut thinly on microtome
- washed
What is haematoxylin?
- basic dye
- affinity for acidic
- stains purplish/blue
What is eosin?
- acidic dye
- affinity for basic
- stains pink
What are the 4 different types of tissue?
- epithelium
- connective tissue
- muscle tissue
- nervous tissue
What is the role of epithelium?
- cover body surfaces and line hollow organs
- mechanical barriers
- chemical barriers
- glands
What is the role of connective tissue
- in the growth, development and homeostasis of tissues
What is the role of muscle tissue?
- specialized cells to generated force by contraction
What is the role of nervous tissue?
- rapid communication between cells
- made up of neurons and their supporting cells (glia)
True or false
“epithelium is non-vascular”
true
What are the 3 different shapes of epithelium?
- squamous
- cubodial
- columnar
What are the 3 different layers of epithelium called?
- simple
- stratifies
- psuedostratified
What is glandular epithelium?
- produces secretory products, such as oil, sweat, tears and milk
What are exocrine glands?
- secret towards apical end
- ducted glands
What are endocrine glands?
- secret towards basal end
- ductless glands
- to circulatory system (look for cappilaries)
3 different types of connective tissue?
- hard
- soft
- blood and lymph
what does connective tissue consist of?
- extracellular matrix
- cells
3 different types of hard connective tissue?
- hyaline
- elastic
- fibrocartilage
3 different types of muscle tissue?
- smooth
- skeletal
- cardiac
Explain smooth muscle
- involuntary
- central nucleus
- no stritations
- visceral
Explain cardiac muscle
- involuntary
- stritated
- single nucleus
- intercalated discs
Explain skeletal muscle
- voluntary
- cylindrical
- multinucleated
- stritated
Explain what multipolar nerves mean?
- many dentrites
- 1 axon
Explain what psuedounipolar nerves mean?
- same direction
Explain what bipolar nerves mean?
- one dentrite
- one axon
What are the 3 different types of glia?
- oligodenrocytes
- astrocytes
- microglia
Role of microglia?
- provide immune surveillance
Role of oligodendrocytes
- produce myelin in the brain and spinal cord
Role of astrocytes?
- support ion transport
- induce blood brain barrier
What are the 3 main salivary glands?
- parotid
- submandibular
- sublingual
What is the most external tissue on the digestive tract?
- muscularis externa
what is the name of the digestive tract nervous system?
-enteric nervous system
explain the histology of bronchi, bronchioles and alveoli
- bronchi larger in size, hyaline cartilage
- bronchioles, smaller, no cartilage, smooth muscle
- alveoli simple squamous epithelium
what is the liver made up of?
- lobules
What shape is a lobule in the liver?
- hexagonal
What veins/arteries are on the corner of a liver lobule?
- hepatic vein
- heaptic artery
Where is the central vein located in a liver lobule
- centre of hexagon
What is unique about the pancrease glands?
- endocrine and exocrine
what does the pancrease endocrine glands secrete?
- insulin
What does the pancrease exocrine glands secrete?
- digestive juices
What are the three layers of blood vessels
- tunica intima
- tunica media
- tunica adventitia
What is the tunica intima?
- innermost of blood vessel
- composed of squamous epithelium
What is the tunica media?
- composed of smooth muscle
What is the tunica adventitia?
- supporting connective tissue
What are the names of the membranes that seperates tunica intima and tunica media?
- internal elastic membrane
What are elastic arteries?
- larger arteries
- provides elastic recoil
- sheets of elastic tissue replaces smooth muscle
Define vasa vasorum?
- large arteries have their own vascular supply
What are capillaries composed of?
- endothelial cells
- basal lamina
what are the 3 types of capillaries?
- continous
- fenestrated
- discontinuous
What are the histological differences in large veins?
- thick tunica adventitia
- contains smooth muscle
Describe erythrocytes
- no nucleus
- red blood cell
- biconcave
- survive 4 months
- 7um in size
Describe neutrophils
- granules
- multi-lobed nucleus
What would eosinophils look like down a microscope
- bilobed nuclease