Resp Lecture 7

Front 1

Cell types in the nasal respiratory epithelium

Back 1

Goblet cells
Basal cells
Brush cells

Front 2

What kind of epithelium in in the nose?

Back 2

Pseudostratified columnar epithelium (the nucleus isn't situated in the baseline so appears stratified, but really only one cell thick)
Each cell has 200-300 motile cilia to help remove the particles

Front 3

Goblet cells

Back 3

•wine glass mucus secreting cells
•No cilia

Front 4

Basal cells

Back 4

•Attached at base of epithelium
•Can differentiate into other epithelial cell types

Front 5

Brush cells

Back 5

•Thick microvilli (NOT cilia)
•Sensory receptors associated with trigeminal nerve

Front 6

Where are the nasal glands located?

Back 6

In the lamina propria

Front 7

What is the purpose of the serous glands in the nose?

Back 7

make a watery fluid secretion to humidify the air and keep the nose moist

Front 8

What is the purpose of the mucus glands in the nose?

Back 8

Make a viscous fluid in the nose to bind and absorb foreign particles

Front 9

How do the olfactory cells work?

Back 9

Sensory cell. They have microvilli that go into the lumen of the nose. They bind odors and once sensed it changes the polarity of the membrane and you get an action potential which generates another action potential, and then the olfactory nerve which will send an afferent signal to the brain.
Animals with a greater sense of smell will have more olfactory cells

Front 10

What are the sustentacular cells?

Back 10

Support cells. They sit next to the olfactory cells and provide physical and metabolic support to the olfactory cells

Front 11

How does the nose clear away smells?

Back 11

The lamina propria has "Bowman's glands" that help clear away the smells

Front 12

What are the cellular and tissue changes as the airways get smaller?

Back 12

• Columnar to cuboidal epithelium
• Goblet cells become less
• Lamina propria decreases in thickness
• Smooth muscle prominent in bronchi, less in respiratory airways, absent in alveoli
• C shaped cartilage rings in trachea become plates in small in smaller bronchi, absent in bronchioles
• Clara (Club) cells evident in bronchioles
• Mucous glands become less common, absent in bronchioles

Front 13

How is the Trachea able to get nutrients and oxygen?

Back 13

The lamina propria has blood vessels

Front 14

What kind of cells are located in the trachea?

Back 14

Pseudostratified columnar epithelium
Goblet cells can secrete mucus into the lumen
Glands in the lamina propria are also capable of secreting mucus

Front 15

What is the purpose of the mucus?

Back 15

Mucus can trap foreign particles, can be cleared via coughing

Front 16

What are the structures in the bronchi?

Back 16

Cartilage plates.

Front 17

What makes up the bronchi?

Back 17

The lamina propria has lots of smooth muscle that spirals, and sensory nerves. There are also blood vessels that come off the aorta for nourishment.
The lumen is lined with columnar epithelium (shorter as the airways get smaller, become more cuboidal). There are also goblet cells that have the ability to release granules into the lumen.
The bronchi also have glands

Front 18

Describe the histology of the bronchioles?

Back 18

1/2mm-1mm diameter. The lamina propria is very small. There are no glands (could interfere with gas exchange; very small airway, any mucus produced will block airway). No cartilage. Smooth muscle control of airway calire (if contracts, can almost close completely.

Front 19

What is the purpose of the elastic fibres in the bronchiole?

Back 19

they help to keep the bronchiole open. When the lung expands on inspiration, the fibres pull the airways open. When it collapses on expiration, prevents complete collapse; keeping the airways open.
Also a bit of smooth muscle that helps prevent the airways from collapsing. However, constricted, they will overpower the elastic fibres

Front 20

What are alveoli attachments?

Back 20

Where the alveoli connect with the airway. In the attachments are elastic fibres all the way around.

Front 21

What is the histology in the respiratory bronchioles?

Back 21

This is the site where some gas exchange occurs. The epithelium is flattened cuboidal, no lamina propria, they receive blood from the capillaries. VERY small amount of smooth muscle, empties into the alveoli where gas exchange occurs.

Front 22

What is the distribution of cells types/tissue in the trachea?

Back 22

Epithelium: Pseudostratified columnar
Goblet cells: +++
Clara cells: Absent
Mucous glands: +++
Cartilage: +++

Front 23

What is the distribution of cells types/tissue in the bronchus?

Back 23

Epithelium:Pseudostratified columnar (starting to become shorter)
Goblet cells: ++
Clara cells: Absent
Mucous glands: ++
Cartilage: ++

Front 24

What is the distribution of cells types/tissue in the Segmental Bronchi?

Back 24

Epithelium:Pseudostratified columnar (becoming shorter)
Goblet cells: +
Clara cells: Absent
Mucous glands: +
Cartilage: +

Front 25

What is the distribution of cells types/tissue in the bronchiole?

Back 25

Epithelium: Columnar/cuboidal
Goblet cells: +
Clara cells: +
Mucous glands: Absent
Cartilage: Absent (elastic fibres and smooth muscle provides support)

Front 26

What is the distribution of cells types/tissue in the respiratory bronchiole?

Back 26

Epithelium: Cuboidal
Goblet cells: Absent
Clara cells: +
Mucous glands: Absent
Cartilage: Absent (elastic fibres and smooth muscle provides support)

Front 27

What are the defense mechanisms of the respiratory system?

Back 27

• Nasal hairs
• *Cough & sneeze reflexes
• Lymphoid organs - tonsils & adenoids
• *Epithelium (lumenal)
• *Mucociliary clearance
• *Specialised small airway defence cells (Club cells)
• Alveolar macrophages

Front 28

How does the columnar epithelium assist in airway defense mechanisms?

Back 28

• boundary to outside world (if this is degraded, allergens and other stuff will interact with the internal environment stimulating immunity)
• interacts with immune cells
• secretes cytokines and mediators on activation• allows dendritic cell processes to sample lumen particles (the particles will go through the lumen to be sampled. If found to be harmful, they will notify the immune system)

Front 29

What is mucociliary clearance?

Back 29

Faster in the larger airways due to faster beating of cilia.
Glands and goblet cells secrete mucous to bind foreign particles. There's a peracilia layer where serous solution is secreted so the cilia can beat. The mucous sits on top. The cilia all beat one way and it pushes the mucous towards the mouth where it is coughed up. CILIA ONLY BEAT IN ONE DIRECTION, TOWARDS THE MOUTH!!

Front 30

What is the problem with mucociliary clearance in cystic fibrosis?

Back 30

There's a faulty iron channel so we no longer have the serous layer, so the mucous just sits on the cilia and bogs them down so they can't beat and the mucous is stuck.

Front 31

What happens to mucociliary clearance in asthma?

Back 31

Mucociliary clearance (MCC) impaired in some diseases eg in asthmait is impaired up to three weeks following allergen challenge(neutrophils: neutrophil elastase involved)
• Can be experimentally measured in sheep by following a radioopaqueTeflon disc up the trachea with a fluoroscope
• Tracheal mucus velocity (a measure of MCC) is 5mm/min in sheep
• Number of drugs devised to increase MCC in diseased states
• Beta-2 agonists increase MCC

Front 32

What are clara cells?

Back 32

Cub cells protect bronchiolar epithelium
• dome shaped cells
• nonciliated, secretory bronchiolar epithelial cells
• function as stem cells for repair in the bronchioles ciliated or nonciliated bronchiolar cells.
• secrete Club cell secretory protein (CCSP, to keep the alveoli open) and a solution similar to the component of the lung surfactant.
• secrtete glycosaminoglycans, proteins such as lysozymes, and conjugation of the secretory portion of IgA antibodies
• Club cells engulf airborne toxins and break them down via their cytochrome P-450 enzymes

Front 33

What is the sneezing reflex?

Back 33

The sneeze reflex is similar to the cough reflex, but it differs in several ways. The source of irritation thatinitiates the sneeze reflex is in the nasal passages instead of in the trachea and bronchi, and theaction potentials are conducted along the trigeminal nerves (CNV) to the medulla, where the reflexstimulus is processed and acted upon through efferent motor pathways. During the sneeze reflex, theuvula and the soft palate are depressed so the air is directed primarily through the nasal passages,although a considerable amount passes through the oral cavity. The rapidly flowing air dislodgesparticulate matter from the nasal passages and propels it a considerable distance from the nose.

Front 34

What are the steps in the sneeze reflex?

Back 34

• Irritant receptors in the nasal airways initiate protective reflex sneezing
• Deep inspiration
• Brief closure of the glottis
• Contraction of respiratory muscles
• Abrupt forced blast of air directed mainly through the nasal passages (Sneeze)

Front 35

What are the steps in the cough reflex?

Back 35

•Irritant receptors in the larynx and trachea (also pharynx (send their signal through the vagus nerve, goes to the cough center of the brain) & bronchi) initiate a protective cough reflex
•Deep inspiration
•Brief closure of the glottis
•Contraction of respiratory muscles (builds up pressure)
•Abrupt forced blast of air directed through the mouth (cough)