Histology/Pathology Flashcards
Is hyperplasia reversible?
Yes
What is hyperplasia?
Increase in cell number - physiologic or pathologic
What is an examples of pathologic condition where hyperplasia and hypertrophy occur at the same time?
Grave disease - thyroid tissue
What cell types are present in the bronchi/bronchiole?
Pseudostratified epithelial cells
Goblet cells
Neuroendocrine cells
Basal Cells
What cell types are present in the alveolar?
Type I and II pneumocytes Alveolar Macrophages Simple squamous endothelial cells Fibroblasts Inflammatory cells
What is atropy?
A decrease in cell size or activity - associated with a reduction in cell metabolism or synthesis of structural proteins. Atropy can also refer to decrease in the size and activity of tissue due to apoptosis
Define involution?
Physiological atropy involving apoptosis eg uterus Post partum, thymus
What is lipofuscin
Pigment left from the autophagosis of cellular components in lysosomes
What stimulates hypertrophy?
Increased demand or hormonal/growth factors
Is hypertrophy always pathologic?
No. Eg Skeletal and cardiac muscle can both undergo physiologic hypertrophy
What is neoplasia?
New growth of cells that is unregulated - eg malignancies. Hyperplasia increases the risk of neoplasia
What are two types of non-dividing cells?
Neurones and cardiac myocytes
How are cells classified in terms of their position on the cell cycle?
Labile - constantly replicating Stable - can re-enter the cell cycle Permanent - can not re-enter the cell cycle
What stimulates hyperplasia?
Growth/hormonal factors
What are some pathologic causes of atropy?
Disuse Denervation Loss of endocrine supply Pressure Inadequate nutrition Loss of blood supply
What is autophagy?
A cell breaks downs some of its own components using lysosomes.
What are some examples of normal hyperplasia?
Replication in endometrium during the reproductive cycle or the replication of epithelial cells during lactation.
What is metaplasia?
Differentiation of one mature adult cell type into another
What is an example of pathological metaplasia?
Pseudostratified columnar epithelium to stratified squamous cells in bronchial airways of the lung in response to smoking
Give an example of physiological metaplasia
Cervical metaplasia: Simple columnar epithelium becomes stratified squamous around the external cervical OS
What is hypertrophy?
Increase in cell size without an increase in cell number. Due to increase synthesis of cell components
What is a terminal bronchiole?
The smallest airway in which gas exchange does not occur
What is the first structure in the conducting airway?
Nasopharynx
What occurs in the nasopharynx?
Tonation and condition of air in th sinuses
Smelling in the olfactory epithelium
Turbinates (warms and moistens) the air
What is the function of the larynx?
Block food from entering the airways
Produce sound as air is forced over it
What cells up the respiratory epithelium of the airways?
Pseudostratified epithelial cells (30%)
Globlet cells (30%)
Basal stem cells (30%)
Brush cells with microvilli (3%)
Serous cells (3%)
Small granuole cells
How long is the trachea? What is it’s diameter?
12cm and 2cm respectively
What are the layers of the trachea?
Mucosa
Submucosa
Adventitia
Why is the trachea constricted during exhalation?
To make sure any dead air in the airways is expelled so as not to be inhaled deeper into the lungs for a second time
Where is the trachea’s cartilage located?
In the adventitia
What makes up the trachea’s mucosal layer?
Respiratory epithelium and lamina propria
What makes up the trachea’s submucosa?
Secretory glands and connective tissue
How many divisions are there of the 2 primary bronchi?
5 - 3 on the right and 2 on the left
How does the cartilage differ in the bronchi cf to the trachea?
It forms plates instead of rings
How does the smooth muscle differ in the bronchi cf to the trachea?
It makes a complete ring around the lumen instead of connecting the C ring cartilage
What does the submucosa of the bronchi contain?
Glands and smooth muscle
What differentiates a bronchiole from a bronchus?
A bronchiole is <2mm and doesn’t have cartilage
How does the cell structure of the bronchioles differ from higher airways?
It loses goblet cells and ciliated epithelials and gains Clara cells
Ciliated cells extend deeper into the bronchioles than do goblet cells, why?
To capture mucus
What keeps bronchioles open?
Radial connective tissue and surfactant
What is the structure of Clara cells?
Columnar to cuboidal with microvilli
What is the function of Clara cells?
Secrete surfactant
Neutralise toxins
What is characteristic of a terminal bronchiole?
It is the last airway where gas exchange does not occur
What is the structure of the respiratory bronchiole epithelium?
Cuboidal to squamous with intermitten alveoli pouches
What is the purpose of alveoli pores?
Allows air to flow between alveoli
What is contained in alveoli walls?
Pore
Capillaries
Lined with squamous cells
What do interalveolar septa contain?
Elastin and reticular fibres to keep alveoli open
What cells make up the majority of the SA of the alveoli?
Type I pneumocytes
What is the function of Type I pneumocytes?
Gas exchange surface
Tight junctions to prevent fluid leaking into alveoli air space
What is the function of type II pneumocytes?
Produce surfactant
Act as stem cells
What are lamellar bodies?
Vessels in type II pneumocytes that contain surfactant
T/F type II pneumocytes can replicate into type I or II pneumocytes
True, required to replace type I pneumocytes
How is the A-C barrier further made thinner?
Fusion of the basal lamina’s of the endothelium and type I pneumocyte
Where do intra-alveolar macrophages go when they are full?
They can travel up the airways or
Stay in interalveolar septum with particles
