Physiology Respiratory System

Nose/Mouth/Nasal passages

filter our large particles

contains goblet cells create mucous

Pharynx

throat

Larynx

voice box

epiglottis and arytenoids

opening to trachea

epiglottis

covers trachea when swallowing

arytenoids

on either side of larynx, controls movement and tension of vocal cords

Trachea

1. Humidify and filter air

2. conduct air

3. trap particles and moves towards pharynx

Bronchi

large splits, wide airways

bronchioles

narrow airways split off of bronchi

humidify air

filter and trap particles

Alveolus

site of gas exchange

mucociliary escalator

bronchioles to nose

cilia move mucus and trapped particles toward pharynx for swallowing

goblet: mucus

ciliated columnar epithelial cells: cilia

sneeze

irritant receptor

1. Inhale

2. vocal folds close

3. abdominal muscles and diaphragm contract

4. pressure in thoracic cavity and lungs increase

5. vocal folds open

6. air forced out

cough

reflex caused by irritant receptors, inflammatory mediators, mechanical stimulation, dust, bronchospasm

Total lung capacity

total volume of air lungs can hold

100 ml/kg

anatomic dead space

volume of airways not involved in gas exchange

3% of tlc (small animals) and 7% of tlc in horse and cow

tidal volume

air inhaled or exhaled during normal breath cycle

10 ml/kg

10% of tlc

functional residual capacity

total air in alveoli after expiration

50 mls/kg

partial pressures

pressure exerted by individual components in air/fluid

oxygen movement

lungs → blood → tissues

CO2 movement

tissues → blood → lungs

Oxygen-hemoglobin dissociation curve

compares partial pressue of O2 to the oxyhemoglobin %

Left shift on OHG curve

Higher affinity

Lower CO2

Higher pH

Lower temp

Right shift of OHG curve

Lower affinity

Higher CO2

Lower pH

Higher temp

bifurcations

divisions in alveolus, creates sacs that maximize surface area for gas exchange

Capillary

smallest blood vessel/ artery

Capillary bed

network of capillaries that surround alveolar sac, provides blood supply to exchange gases with alveolus

Macrophages

eats foreign particles

antibodies

proteins that bind to specific foreign particles to neutralize

surfactant

fluid, phospholipid complex

reduces surface tension and keeps alveoli from collapsing

medulla oblongata function in breathing

rate and rhythm

pons function in breathing

rate and depth

stretch receptors

lungs stretch limit, sends afferent vagus nerve signal to pons to stop

chemoreceptors

built into blood vessels, measures chemicals in blood