Histology Flashcards
Trachea Cross Section
Describe how the structures functions relate to the trachea:
C = supports tracheal mucosa preventing it from collapsing during inspiration
L = Same as T, assists with contraction and coughing, only a few stands
T = bands of smooth muscle, join the free ends of the rings posteriorly, contraction reduces trachea diameter assisting with raising intrathoracic pressure when coughing
M = secretes mucous (traps dirt and pathogens) and water molecules
Trachea
Describe how the structures functions relate to the trachea:
E = Barrier to infection from pathogens, dirt and other harmful molecules
LP = Elastic recoil as made of elastin during inspiration and expiration, with blood vessels (highly vascularised) contributes towards warming the air
SM = Warm up and moisten the air passing into the lungs, helps provide support (connective tissue) and elasticity
F = strength and expansion during inhalation and exhalation
Bronchus
Describe how the structures functions relate to the bronchus:
LP – Lamina propria, elastic so gives elasticity during inhalation and exhalation
M – Smooth muscle, helps with airway narrowing and inflammation of the bronchus
S – Submucosa, provides a strong cell population for immunological defences
G – Seromucinous glands, secretion of serous and mucinous cells which help with host defence
C – Cartilage, structural support
What the of epithelium is being shown?
Explain the roles of the following cells that can be found within this epithelium,
Goblet
Basal
Ciliated columnar epithelium
Bronchial respiratory epithelium
Goblet Cells - secrete mucin to create a protective mucous layer
Basal cells - provide an attachment site for ciliated and goblet cells on the basal lamina and help with injury to the epithelium
Ciliated columnar epithelial cell - move microbes and debris up and out of the airways often with the help of mucous
How does the bronchiole differ from the bronchus?
Missing:
submucosa
submucinous glands
cartilage
most goblet cells (terminal and respiratory) replaced by club cells
Different:
Neuroendocrine cells which secrete peptide hormones to help with muscle tone regulation
Distended thin-walled pulmonary artery branch lying alongside it
What are the similarities between the bronchus and bronchioles?
Both have smooth muscle for contraction and control of air flow, both have ciliated epithelium columnar cells and a few goblet cells
Define terminal bronchioles:
Define respiratory bronchioles:
Terminal bronchioles:
Only found in the conducting region of the respiratory tract (no gas exchange occurring) and are the smallest diameter passages.
Respiratory bronchioles:
Branch off the terminal bronchioles, have thinner walls that contain a small number of alveoli. They participate in gas exchange.
Identify the structures in the alveolar histology sample:
T = Terminal bronchioles
AD = Alveolar duct
R = Respiratory bronchioles
A = Alveoli
AS = Alveolar sacs
AR = Alveolar ring (surround ducts contain smooth muscle, collagen, elastic fibres)
What are alveoli?
What is the function of the alveoli?
Minute polygonal (many sides) chambers
Allows gas exchange to occur between the capillaries (blood) and the respiratory system
What do the letters annotating the alveolus diagram stand for?
P1 = type l pneumocytes ( gaseous exchange barrier)
P2 = type ll pneumocytes (produces surfactant to reduce surface tension)
M = alveolar macrophages (immune cells for inhaled pathogens)
E = capillary endothelial cells
C = capillaries
Which cell type produces surfactant?
Where are they located?
Why is surfactant important?
Type ll pneumocytes
Found in the lining epithelium of the alveoli
Produces surfactant to reduce surface tension of the alveolar preventing collapse during expiration
What are the 3 components of the alveolar wall?
Surface epithelium
Supporting tissue (‘skeleton’ of collagen fibrils and elastic fibres)
Blood vessels (capillaries)
Which layers does oxygen diffuse through to reach the lung capillaries?
Alveolar lining epithelium (and surfactant)
Basement membrane
Capillary epithelium
What is the respiratory mucosa composed of?
Epithelium and lamina propria
What are the features of the respiratory epithelium?
What is the main cell type found in the epithelium?
Pseudostratified*, ciliated, columnar
Goblet cells - produce mucous
*one layer of cells that looks like lots of layers
What is important to know about the lamina propria in the respiratory mucous?
Highly vascularised with thin walled veins so helps to warm and humidity blood but if poked with an endoscope with bleed A LOT
Fill in the missing labels:
(1,2,3 - 6,8,9,10,11)
1 - respiratory epithelium
2 - lamina propria
3 - periosteum
6 - artery
8 - capillary net
9 - venous cavernous bodies
10 - vein
11 - nasal glands
What are the two components of the mucosa of the larynx?
The epithelium and the lamina propria
What are the two types of epithelium found in the larynx and where are they located?
Stratified squamous - entrance (epiglottis) and on the folds as they are exposed to the oral cavity
Pseudostatified ciliated - inside the larynx, also contains mucous glands
