physiology quiz (dr. Butcher 1)

what is the mucosa made of in the nasal cavity? where is it underlying?

epithelium and lamina propria, it underlines submucosa, turbinates (trabecular bone scrolls)

turbinates?

what type of cells do the vestibule (rostal), respiratory portion (middle), and olfactory portion (caudally) have?

• vestibule: stratified squamous epithelium that’s continuous with skin

• respiratory portion (middle): ciliated pseudostratified columnar epithelium + goblet cells, olfactory cells; tubuloalveolar glands

• Olfactory portion (caudally): Similar to respiratory portion but increased olfactory cells

what does the larynx/pharynx look like in terms of tissue/cells?

• similar to adjacent cells

• part ciliated psuedostratified columnar and parr stratified squamous, depending on location

• both contain gland and underlying sheets of skeletal muscle

• larynx contains cartilage for support

what is the trachea? structure?

• it is the passage of air from larynx to the lungs

• has C shaped tracheal rings made of hyaline cartilage for structural support

  • dorsally lined by trachealis m (smooth)

• has pseudostrat. columnar epithelium

  • Mucociliary apparatus/escalator

when does the trachea have opened/closed rings?

closed in non mammals (so like reptiles, birds)

• dont have that lined trachealis

open in mammals

Mucocilary apparatus is important why?

for the clearance of dust/dirt and inhaled pathogens from the LRT

bronchi

branch off trachea into mainstem bronchi before lung

how does tissue transition? what cells to what in the lung?

what is the pleura, bronchi? alveoli

lobe vs lobules?

what is this and the definition?

bronchus

• basically same as trachea

• 1. Ciliated pseudostratified columnar           

            epithelium + goblet cells

       2. Bronchial glands

       3. Cartilage

       4. Smooth muscle

       5. Bronchus associated lymphoid tissue

           (BALT)

Bronchiole

Similar to bronchus

• tissue: Ciliated pseudostratified columnar epithelium ( smooth muscle)

• terminal progress of tissue: Ciliated columnar → ciliated cuboidal→ non-ciliated cuboidal

does the bronchiole have cartilage/ glands?

no

what is the alveolus? epithelial there?

• terminal outpouching of bronchioles

• simple squamous epithelium (type 1 pneumocytes)

  • gas exchange

• type II pneumocytes: much fewer; cuboidal, produce surfactant

• thin layer of supporting collagen (alveolar septum)

bird anatomy

• primary bronchi (mesobronchi): analogous to mammalian bronchi: ciliated pseudostrat. columnar

• second bronchi: ciliated columnar

• Tertiary bronchi (parabronchi): fenestrated cuboidal epithelium

• artia (air vesicles) and air capillaries: analogous to aveloi, simple squamous; site of gas exchange

fish structure

Basically similar to alveolar structure for gas exchange but in Direct contact with environment

secondary lamellae

Gas exchange occurs

main function of respiration

provide oxygen to tissues and remove Carbon dioxide

1. pulmonary ventilation: in flow and outflow of air between alveoli and atmosphere

2. diffusion of oxygen and carbon dioxide: between alveoli and blood

3. transport of oxygen and carbon dioxide: in blood and body fluids

4. regulation of ventilation

what does the upper respiratory tract contain? the lower?

• Upper: Nasal cavity, sinuses, nasopharynx, larynx

• lower: Trachea, bronchi, lungs, pleural cavity

what happens in nasal cavity?

• air is warmed, humidified, and partially filtered (air-conditioning function)

• Large particles trapped in mucous (goblet cells, submucosal glands) and coughed up or swallowed (turbulent precipitation)

  • Mucociliary elevator

    • Small particles trapped in mucous

    • Ciliated epithelium (directionally beat toward pharynx)

Nervous and Local Control of Respiratory Tree: what types function

• Parasympathetic nervous system

  • Branches of Vagus nerve

  • Secrete Acetylcholine (Ach)

  • Parasympathetic stimulation increases bronchoconstriction and secretions

• Sympathetic nervous system

  • Mediated by circulating catecholamines (NE, EPI) and B2-adrenergic receptors

  • Sympathetic stimulation causes bronchodilation

• Local secretory factors

  • Chemical, mechanical, humoral

respiratory pathways: types and what do they do

• Conduction

  • Nasal cavity, trachea, bronchi

  • Pseudostratified ciliated columnar cells with goblet and serous cells

  • Cartilage rings and plates keep larger two open, with remaining walls being smooth muscle

• Transitional

  • Primary, secondary, tertiary bronchioles

  • Progressively less ciliation

  • Bronchioles are kept open with pressure and mostly smooth muscle, with pulmonary epithelium at the terminal bronchioles

  • Normal respiratory conditions = low pressure gradient (1-2 cm H2O) or low resistance

• • Gas Exchange

  • Alveolar duct, atrium, alveolar sac, alveolus

what happens without force to keep the lung inflated

• lung collapses bc the lung and the chest walls are not attached

how is lung positioned in the body

• lung floats in thoracic cavity surrounding by pleural fluid

pleural pressure at rest vs during inspiration

• at rest→ slight negative pressure and thus slight suction

• during inspiration → expansion of cavity lowers pleural pressure further

• pressures reversed during expiration

Where does gas exchange occur in the respiratory system

• Nasal Cavity

• Trachea

• Bronchioles

• Alveoli

• Alveoli

Which receptor predominates in neural control of the respiratory system?

• Mucous receptor

• Acetylcholine

• Alpha receptors

• Beta-2 receptors

• Beta-2 receptors

The mucociliary elevator in the bronchi move large particles downward toward alveoli •

True •

False •

Not enough info given

False •

What happens to the lung when the diaphragm contracts?

• Lung expands

• Lung contracts

• Rib cage movement

• Not enough information given

• Lung expands

At rest, pleural pressure is slightly _______, and then _______ with inspiration.

Negative; decreases

• Negative; increases •

Positive; decreases

Positive; increases

• Negative; decreases

variables that affect gas exchange

• the Gas exchange membrane/respiratory exchange membrane ( a thin layer of tissue that separates animal from env. medium)

• O2 movement into the lungs via diffusion/convection

• rate of diffusion (depends on surface area and thickness of membrane)

active ventilation: what is it? pathway? E? how reliable?

creation of currents of air/water flowing to/from gas exchange membrane

• uses E (contracting or beating cilia E)

• pathway across membrane: unidirectional, tidal (bidirectional) or non directional

• considered more reliable and controllable

passive ventilation

environmental air/water directly or indirectly induce flow to/from a GEM

what is compliance?

a measure of the lungs' ability to stretch and expand

• high compliance: lungs expand easily and vise versa

is inspiration work? how does it work

yes, elastin and collagen fibers are interwoven among lung parachyma provide the elastic forces

when u breath in, ur muscles have to generate enough pressure to overcome the forces trying to keep the lungs closed

• need 3x the transpleural pressure ( pressure difference to keep lung expanded) to expand air-filled lungs

• surface tension: in each alveolus, there is a thin layer of fluid, creating surface tension, which tends to make the alveolus shrink/collapse

respiratory muscles have to work against what?

elastic recoil and surface tension

expiration is what

mostly elastic recoil

surfacant

surface active agent in water

• secreted by type 2 alveolar epithelial cells

• it interrupts the attraction between the water molecules (decreases surface tension)

• increased surfactant = decreased surface tension and vise vera

Neonatal Respiratory Distress Syndrome (RDS) in Pre-term animals

premature animals dont have sufficient mature type 2 alveolar cells- dont produce enough surfacant

• Traditional administration through a breathing tube (endotracheal tube) connected to a ventilator

• infasurf: a replacement of surfacant, Calfactant - extract of natural surfactant from calf lungs

• survanta

• CUROSURF

• all types of replacement for surfacant

work of inspiration

• Expansion of lungs against lung and chest elastic forces (compliance or elastic work)

• Overcoming viscosity of the lung and chest wall structures (tissue resistance work)

• Resistance to movement of air into the lungs (airway resistance work)

the 4 pulmonary volumes? what happens when u add them all together?

1. tidal: air inspired or expired

2. inspiratory reserve: extra volume that can be inspired over tidal

3. expiratory reserve: max extra volume expired with forceful expiration after tidal

4. residual: volume remaining after a forceful expiration

added together, lungs can be expanded

correlating the volumes to each other

1. Inspiratory = Tidal + IRV = how much air can be breathed in

2. Functional residual = ERV + residual = how much air is in lungs at the end of expiration

3. Vital capacity = IRV + TV + ERV = max air expelled after max inspiration

4. Total lung = VC + RV = max volume lungs can be expanded

Alterations to pulmonary volumes and capacity depend on what?

• Physical fitness

• Age

• Height

• Sex

• Altitude

Pulmonary function test assessed by?

spirometry: used to monitor airway pressures, flows, and volumes

gas exchange areas

alveoli, alveolar air sac, alveolar ducts, and respiratory brinchioles

dead space

air that never reaches gas exchange areas

rate of alveolar ventilation is important for what?

• its the new air entering alveolar/min

• its a major factor in determining concentrations of oxygen and CO2 int he alveoli

How does oxygen cross a gas-exchange membrane?

Diffusion

Convection

Active transport of ions

diffusion and/or convection

Diffusion

What are force(s) in the alveoli that increase the work of inspiration?

Elastin and collagen stretching

Surface tension

Surfactant

Elastin and collagen stretching and surface tension

Elastin and collagen stretching and surface tension

Tidal volume describes the amount of air inspired or expired at rest •

True

False

Not enough info given

• True

What term(s) describe the max volume lungs can be expanded?

Total lung capacity

Vital capacity

Residual volume

Tidal volume

• Total lung capacity

Air that never reaches gas-exchange areas is termed ______________

Alveolar ventilation

Dead space

Oxygen uptake

Spirometry

Dead space