Histology Flashcards
What is the inner cytosol?
Solution of proteins, electrolytes and carbohydrates
What is a cytoskeleton made of?
Thin, intermediate filaments and microtubules
Role of the plasmalemma?
Separates plasma from outside environment
Describe the arrangement of the phospholipid bilayer/plasmalemma?
Hydrophilic heads at outer and inner surfaces and hydrophobic tails at centre surrounding protein structure
What is the plasmalemma made up of?
Integral proteins
Embedded cholesterol
Phospholipid bilayer
What can the plasmalemma do?
Exocytose and endocytose material
The plasmalemma is impermeable. True or False?
FALSE
Selectively permeable
Organelles in he cytoplasm?
Mitochondria RER SER Golgi apparatus Lysosomes Nucleus
Role of mitochondria?
Generate ATP
Synthesis of certain lipids and proteins
Role of RER?
Protein synthesis
Role of SER?
Cholesterol and lipid synthesis/ detoxification
Role of golgi apparatus?
Modification and packaging of secretions
Role of lysozomes?
Hydrolytic enzymes of intracellular digestion
Role of nucleus?
Contains genetic code
Width and substance of microfilaments?
7nm
Actin
Width and substance of intermediate filaments?
> 10nm
Composed of proteins
Width and substance of microtubules?
25nm
Composed of tubulin
Where do microtubules originate from?
Centrosome
Which substances attach to microtubules and move along?
Dynein and kinesin
What is on the outer nuclear membrane?
Ribosomes
What is the site of RNA synthesis?
Nucleus= mRNA, tRNA and rRNA
Where is rRNA synthesized?
Nucleolus
Where are ribosomes formed?
In the nucleus
What is the role of ribosomes and its make up for this?
Small subunit which binds RNA and large subunit which catalyses formation of peptide bonds
What happens in RER?
Protein synthesis
Initiation of glycoprotein formation
What happens in SER?
Continues processing of proteins from RER
Site of lipid synthesis
What consists of the Golgi apparatus?
Composed of a group of flattened membrane bound cisternae
What happens in the golgi apparatus?
Transport vesicles arrive at golgi from SER
Modifies & packages macromolecules from SER
What is the membrane in mitochondria folded to form?
Cristae
Types of intracellular junctions?
Occluding/Tight junctions
Anchoring junctions (desmosomes/hemidesmosomes/adherant)
Communicating/Gap junctions
What is role of occluding junctions and their other name?
Tight junctions
- Link cells to form diffusion barrier
- Prevent diffusion
Role of anchoring junctions?
Provide mechanical strength
Adherent junctions role?
Link submembrane actin bundles of adjacent cells
Role of desomsomes?
Link submembrane intermediate filaments of adjacent cells
Hemidesmosomes?
Link submembrane intermediate filaments of cells to extracellular matrix through transmembrane proteins
Role of communicating junctions and their other name?
Allow movement of molecules between cells
Gap junctions
Where are Gap junctions found?
Epithelium, but also in smooth muscle and cardiac muscle
Structure of Communicating junction?
Circular patch studded with pores (produced by connexion proteins)
Process of endocytosis?
Membrane invaginates, fuses and a newly made endocytotic vesicle buds into cell
How is endocytosis mediated?
Receptors
Process of phagocytosis?
Bacteria binds to cell surface
Cell engulfs it to form phagosome
Binds with lysozome containing digestive enzymes
Common stain?
H&E
What is H&E?
Haematoxylin- purple basic dye
Eosin- pink acidic dye
4 basic tissues types?
Epithelium
Connective tissue
Muscle
Nervous tissue
What tissue type forms glands?
Epithelium
What do all types of epithelium have?
Basal lamina
Epithelium is non-vascular. True or False?
TRUE
Is epithelium usually polarised?
YES
Apical and basal sides differ
Functions of epithelium?
Mechanical and chemical barrier Absorption Secretion Containment Locomotion
3 classifications of cell types?
Squamos - flattened
Cuboidal - cube
Columnar -Tall & thin
How many layers in simple epithelium?
- 1 layer
How many layers in pseudostratified epithelium?
Tissue appears to have multiples layers
Stratified epithelium contains 3 or more layers? True or False
FALSE
2 or more
Cell/tissue surface specializations?
Prominent microvilli
Cilia
Keratinised
Where is product secreted in Endocrine glandular epithelium? And how?
Towards basal end of cell
Distributed by vascular system
Ductless glands
Exocrine glandular epithelium distribution of secretion and gland type?
Product secreted towards apical end of cell
Ducted glands
What is the role of connective tissue?
Forms the framework of the body, dynamic role in development, growth and homeostasis of tissues and energy storage (fat)
3 types of connective tissue?
Soft connective tissue
Hard connective tissue
Blood and lymph
Examples of soft connective tissue?
Tendons Ligaments Mesentery Stoma of organs Dermis of skin
What is dense regular soft connective tissue compared to irregular?
Fibres alligned in regular
Fibres run in many directions in irregular
Examples of hard connective tissue?
Bone and cartilage
3 types of cartilage?
Hyaline
Elastic
Fibrocartilage
Examples of hyaline cartilage?
Articular cartilage
Tracheal rings
Costal cartilage
Epiphyseal growth plates
Connective tissue consists of?
Fibres- collagen, reticular and elastic fibres
Ground substance
Tissue fluid
Cells (adipose tissue, fibroblasts, osteocytes, chondrocytes)
What is muscle force?
Movement of actin fibres over myosin fibres?
3 types of muscle?
Cardiac
Smooth
Skeletal
Describe smooth muscle?
Involuntary and non-striated
Describe skeletal muscle?
Voluntary and striated
Multinucleated
(nuclei are elongated and located at the periphery)
Describe cardiac muscle?
Involuntary and striated
Have intercalated discs
Contains multiple intercellular junctions to maintain mechanical integrity
Which muscle types are striated?
Cardiac and skeletal
Which muscle types are involuntary?
Cardiac and smooth
Which muscle types are multinucleated?
Skeletal
What does nervous tissue consist of?
Neurons and their supporting cells (glia)
What is the role of nervous tissue?
Control function and allows for rapid communication between different parts of the body
What is nervous tissue surrounded by?
Connective tissue coat
What Nervous system are meninges found in ?
CNS
Which type of connective tissue is in the PNS?
Epineurium
Types of glia?
Astrocytes
Oligodendrocytes
Microglia
Schwann cells
Role of astrocytes?
Support and ion transport
Role of oligodendrocytes?
Produce myelin
Role of Microglia?
Provide immune surveillance
Role of schwann cells?
Produces myelin and supports axons in the PNS
Salivary glands in the GI tract?
Parotid
Sub-mandibular
Sublingual
The ducts in GI system are striated. True or False?
TRUE
4 major layers from oesophagus to anus?
Mucosa
Sub-mucosa
Muscularis mucosa
Serosa/adventitia
Layers of mucosa in GI tract?
Epithelium- sits on basal lamina
Lamina propria - loose connective tissue
Muscularis mucosae - Thin layer of smooth muscle
Describe the sub-mucosa of GI tract?
Loose connective tissue
How many layers of muscle in the muscularis mucosae?
2 layers (thick) Inner circular and outer is longitudinal
Role of serosa?
Outer layer of connective tissue that either suspends digestive tract or attaches to other organs
Where is non-keratinized stratified squamous epithelium in the body?
Oral cavity
Pharynx
Oesophagus
Anal Canal
What type of mucosa is the mucosa in the anal canal?
Protective mucosa
non-keratinized stratified squamous epithelium
Describe absorptive mucosa and where you would find it?
Simple columnar epithelium with villi and tubular glands
SI
Where would secretory mucosa be found and how does it differ from absorptive?
Found in stomach
DOESN’T have villi
Where would you find protective and absorptive mucosa?
Large intestine
Just tubular glands and simple columnar epithelium
Outer longitudnal muscle of Large intestine, what is special about it?
NOT continuous
Found in 3 muscular strips called teniae coli
What is he Digestive tract nervous tissue?
Enteric nervous system
What is the ENS?
Ganglia between 2 muscle layers that make up muscularis externa
What epithelium lines the trachea?
Respiratory epithelium
Differences between bronhci and bronchioles?
Bronchus= large diameter airways with hyaline cartilage in their wall Bronchioles= Small airways, no cartilage, mainly smooth muscle
What are alveoli lined by?
Simple squamous epithelium
Ratio of cells: plasma in blood?
45% cells and 55% plasma
Lifespan of a red blood cell?
4 months
Types of WBC?
Neutrophils Eosinophils Basophils Monocytes Lymphocytes
Layers of an artery?
Tunica Adventitia - Supporting connective tissue
Tunica Media - Smooth muscle
Tunica Intima - endothelial cells
What is endothelium?
Simple squamous epithelium of blood vessels
Structure of an arterioles?
1 or 2 layers of smooth muscle in tunica media and almost no adventitia
Capillaries consist of?
Endothelial cells, pericytes and a basal lamina
What are pericytes and where are they?
Connective tissue cells + contractile properties
Capillaries
3 types of capillaries?
Fenestrated
Continuous
Sinusoidal
Where are fenestrated capillaries? What do they have?
Gut mucosa, endocrine glads, kidneys
Pores
Where are continuous capillaries?
Muscle, nerve, lung, skin
What is special about sinusoidal capillaries?
Have large gaps
Where are sinusoidal capillaries?
Liver, spleen & bone marrow
What do venules consist of?
Endothelium and pericytes
What differs in large veins compared to small veins?
Large veins have thick tunica adventitia
What is the structure of veins?
Tunica intima
Thin continuous tunica media
Few layers of smooth muscle cells