Overview of Respiratory system

What is part of the upper respiratory tract?

• Nose

• Nasopharynx

• Pharynx

• Larynx

What is part of the lower respiratory tract?

Trachea

Lungs

Bronchi

alveoli

What are the primary functions of the respiratory tract?

• exchange oxygen and carbon dioxide between blood and the atmosphere

• olfaction - smell and taste

• Voice

What are the secondary functions of the respiratory tract?

• Warming and humidifying incoming air

• Moistening of cell lining

• Keeping lining clean

• keeping airways open during pressure changes

• Keeping alveoli open against surface tension

What is the anatomy of the nasal cavity?

• blood supply

• hairs

What is the anatomy of the sinuses?

• air cavities in the cranial bones

What is the anatomy of the larynx?

• Speech - pitch and volume

• Preventing material reach the lower respiratory tract

• stimulation of larynx by injected matter produces strong cough reflex - vagal receptors

What is the anatomy of the pleura?

• each lung is surrounded by two membranes (pleurae)

• the outer (parietal) pleura

• the inner (visceral) pleura

• space is filled with fluid - surface tension, reduce friction

What is the anatomy of trachea?

• ends where it bifurcates into 2 main bronchi at the level of the sternal angle

• Horseshoe cartilaginous rings

What is the anatomy of the main bronchi?

• left main bronchus - longer than right

• bronchi subdivide into lobar and segmental until terminal bronchioles reached

• bronchi - cartilage

• bronchioles - no cartilage

• terminal bronchiole - supplies acinus

What is the anatomy of alveolus?

• lined - single layer of flat epithelial cells

• type 1 pneumocytes

• type 2 pneumocytes

What is a pulmonary surfucant?

A liquid in the lungs that helps keep the air sacs open and allows for breathing

• secreted by type II pneumocytes

How do surfactants work?

• lowers surface tension - surfactant reduces the surface tension between water molecules in the lungs. This allows the lungs to expand and take in the air.

• prevents collapse - surfactant coats the air sacs in the lungs preventing them from collapsing

• protects from infection - surfactant protects the lungs from inhaled particles and microorganisms

What is laplace’s law?

- the smaller the bubble, the greater the inward pressure trying to collapse the bubble

All of the water molecules in the walls of the bubble are trying to move closer to one another. The net effect is to reduce the surface area of the bubble, reducing the diameter of the bubble and collapsing the overall size of the bubble

What is in the nasal cavity lining?

• hairs

• olfactory mucosa - small area, roof of nasal cavity, pseudostratified epithelium (respiratory epithelium), ciliated, olfactory cells

• respiratory mucosa - cilia, goblet cells, serous and mucous glands, venous plexus

What is clearance?

goblet cells - mucus

What are cilia?

• covered with a thin layer of mucus

• move in coordinated waves - mucociliary escalator

What does pulmonary ventilation refer to?

The movement of air into and out of the lung

What is the function of surfactant in the lungs?

Helps prevent the alveoli from collapsing

What does the dorsal respiratory group do?

Controls the contraction of the diaphragm and external intercostals

What does a rightward shift of the oxygen dissociation curve indicate?

Hemoglobin has a lower affinity for oxygen, promoting oxygen release to tissues.

What causes a rightward shift in the oxygen dissociation curve?

• ↑ CO₂ (Bohr effect)

• ↑ H⁺ (lower pH)

• ↑ Temperature

• ↑ 2,3-BPG (a molecule in red blood cells)

What does a leftward shift of the oxygen dissociation curve indicate?

Hemoglobin has a higher affinity for oxygen, making it hold onto oxygen more tightly.

What causes a leftward shift in the oxygen dissociation curve?

• ↓ CO₂

• ↓ H⁺ (higher pH)

• ↓ Temperature

• ↓ 2,3-BPG