Histology Flashcards
What are organelles?
Membrane bound proteins that are essential for life
What are inclusions?
Proteins that are not membrane bound and non-essential
What are embedded in the cell membrane?
Integral, peripheral and transverse proteins
Cholesterol
What is the difference between euchromatic and heterochromatic nuclei?
Euchromatic - dispersed, actively transcribed
Heterochromatic - condensed, not actively transcribed
What is the other term for tight/occluding junctions?
Zonula occludens
What is the function of tight/occluding junctions?
Barrier that prevents diffusion
What is the function of anchoring junctions?
Anchor epithelial cells to the space they’re meant to be in
What is the function of zonula adherens?
Anchoring junctions that link actin bundles
What is the function of macula adherens?
Desmosomes -link intermediate filaments of adjacent cells
What is the function of communicating/gap junctions?
Selective diffusion
What is an example of where gap junctions are important?
Smooth muscle for excitation spread
What is the main staining called?
Haematoxylin and Eosin
What do H&E stain, and what colour do they stain them?
Haemotoxylin - stains acids purple/blue
Eosin - stains bases pink/red
What are the functions of epithelium?
Barrier
Absorption/secretion
Containment
Locomotion
What are the subclasses of epithelium shape?
Squamous
Cuboidal
Columnar
What are at the subclasses of epithelial organisation?
Simple
Stratified
Pseudostratified
What is the difference between endocrine and exocrine glands?
Endocrine secretes into a vessel
Exocrine secretes into everything else
What are the two types of connective tissue?
Soft and hard
What cells are present in the connective tissue?
Fibroblasts
Adipose
Osteocytes
Chondrocytes
What are the types of soft connective tissue?
Loose
Dense regular
Dense irregular
What does hard connective tissue make up?
Cartilage
Bone
What are the different types of muscle?
Smooth
Skeletal
Cardiac
What is the structure of smooth muscle?
No striation
Involuntary
Vascular
What is the structure of skeletal muscle?
Striated
Voluntary
Multi-nucleated
What is the structure of cardiac muscle?
Striated
Single nucleus
Intercalated discs at cell-cell attachments
What do nerves consist of?
Neurones + glia surrounded by meninges or epineurium
What are glia?
Neuron support cells
What are the different types of nerves, and what are their structures?
Multipolar - many dendrites, one axon
Bipolar - one dendrite, one axon
Pseudo-unipolar -short process gives rise to axon in both directions
What is the order of the layers of blood vessels, from innermost to outermost?
Tunica intima
Tunica media
Tunica adventitia
What type of epithelium makes up the layers of blood vessels?
Intima - simple squamous epithelium
Media - smooth muscle
Adventitia - connective tissue
What separates the layers of blood vessels?
Internal and external elastic membrane
What are elastic arteries?
Larger arteries where a significant amount of smooth muscle has been replaced by elastic fibres
What are the subtypes of capillaries, and examples of when they are used?
Continuous (muscle, nerve lung, skin)
Fenestrated (gut, mucosa, kidney)
Discontinuous/sinusoidal (liver, spleen)
What is the flow of blood in capillaries controlled by?
Pre-capillary sphincters
How does the adventitia and media of veins compare to arteries?
Veins have thicker adventitia and less smooth muscle in media
Do small or large veins have valves?
Small
45% of blood is plasma, true or false?
False - 55%
What is plasma made of?
Water (90%)
Nutrients and salt
Proteins
What are the categories of blood cells?
RBCs
WBCs
Platelets
What is an example of red blood cells?
Erythrocytes
What are the two categories of WBCs?
Granulocytes
Agranulocytes
Which WBCs are granulocytes and which are agranulocytes?
Granulocytes: neutrophils, eosinophils, basophils
Agranulocytes: monocytes and macrophages, lymphocytes
How are platelets produced?
By megakaryocytes in bone marrow
Do platelets have a nucleus?
No
What do neutrophils look like?
Prominent, multi-lobed nuclei
Don’t stain well
Granules
What do eosinophils look like?
Bi-lobed nucleus
Stain pink
Granules
What do basophils look like?
Bi-lobed nucleus, but can be obscured by granules
Stain purple
What do monocytes look like?
Kidney bean nucleus
Stain purple
What do lymphocytes look like>
Large round nucleus
Thin cytoplasm
What is the function of neutrophils and where do they reside?
Circle inactivated until inflammation stimulates entry into tissue
If not circulating - reside in specific portion of bone marrow
Where do eosinophils reside?
Circulate for 8-12 hours then reside in spleen, lymph nodes, GI tract and other tissues
What is the function of eosinophils?
Release granules which induce/maintain inflammation in allergic reactions, asthma and parasitic infection
Which WBC have high affinity IgE receptors?
Basophils
What are monocytes?
Precursors of macrophages
