HP-Chapter 17

What is external respiration

Movement of gasses between the environment and the cells in the body

What are the 4 integrated processes of external respiration

1. Exchange of Air between atmosphere and lungs (Ventilation). Inspiration (inhalation) Expiration (exhalation)

2. Exchange of CO2 and )2 between lungs and the blood

3. Transport of CO2 and O2 in the blood

4. Exchange of gasses between blood and cells

Which cells in the blood are responsible for oxygen delivery?

Erythrocytes

What does the respiratory system refer to?

Structures that are involved in ventilation and gas exchange

What are the three sets of structures that make up the respiratory system?

1. Conducting System (passages of airways that leave from the external environment to lungs

2. Alveoli: Interconnected Sacs associated with pulmonary capillaries (Exchange Surface as O2 moves air to blood and CO2 from blood to air)

3. Thorax: associated with bones and muscles in the chest cavity

What does the upper respiratory system have?

Mouth, Nasal Cavity, Larynx, Pharynx

What does the lower respiratory system have?

Trachea, Branches of Bronchi, and Lungs

What is the thorax surrounded by

Bones of the ribcage and spine and they are associated muscles (Thoracic Cage

What is in the thoracic cage?

Ribs and Spine from top, and diaphragm from the bottom, 2 sets of intercostal muscles as well

What are the muscles in the thoracic cage used for?

Inspiration and Expiration

What is the function of the pericardial sac with respect to heart function?

It lubricates the heart so it can move freely in the chest cavity

What do lungs contain?

Springy Tissue filled with air

What are the lungs surrounded by

Pleural Cavity

How does the pleural cavity lubricate the lungs?

By making a moist slippery surface

What do the upper airways do?

1. Provide a route for air to reach the lungs

2. Condition the air before it reaches the alveoli

What are the 3 things airways do?

1. Warms the air to body temp

2. Increases the humidity of air

3. Filters foreign materials

Where does air filtration happen?

Trachea and bronchi

What do Trachea and bronchi have?

Ciliated epithelium (coated with a watery saline solution)

What is the pathway of the water saline solution

Created with presence of anion channel>allows Cl- ions to flow out> Draws water and Na+ out of the pathway

What is on top of the saline layer?

Mucus layer that traps inhaled particles

What is the mucociliary escalator?

Movement of cilia up to pharynx

What is the pathway of air flow from the larynx?

Larynx>Trachea>Left Pulmonary Bronchus> Bronchiole>Alveoli

What does the presence of smooth muscle on the bronchioles tell you about this part of the respiratory system

It is regulated by the autonomic nervous system

What is the primary function of the alveoli?

Site of exchange for gasses between blood and air

What part of the circulation gives rise to the capillaries between the alveoli?

The pulmonary circulation

What is air made out of?

78% Nitrogen, 21% Oxygen, Rest other things

What is Dalton’s Law

Pair=Pnitrogen+Poxygen

Nitrogen and Oxygen are the partial pressures

How is partial pressure determiend

Relative abundance of the mixture which is also independent of molecular size

For humid gas, how do you calculate the pressure

Pgas=(Patmosphere- Pwater) % gas

What does Air Flow require

Pressure gradient

Air flows from where to where

From an area of high pressure to an area of low pressure

For air needing to flow into the lungs, how should the pressure between the lungs and the atmosphere be

Atmosphere should be more than the lungs

Boyles Law

P1V1=P2V2

What is ventilation

Exchange of air between atmosphere and alveoli

What does a single respiratory cycle have?

Inspiration followed by expiration

What do pulmonary function tests use?

Spirometer

What is a spirometer used for?

Captures air of volume moved from each breath

The respiratory system in the spirometer forms what system?

Closed

For the chart, what corresponds with what?

Inspiration graph up, Expiration Graph down

What is one cycle

One inspiration and one expiration

How should you breathe to get tidal volume?

Quietly

How is tidal volume measured?

Peak-Troph

How do you get expiratory reserve volume?

Exhale as much as possible

What is the inspiratory reserve volume?

Inhale as much as possible

What is the reserve volume?

End of expiratory reserve volume till the end of all volume

What is the vital capacity?

Sum of IRV + Vt + ERV

For Air to flow in the lungs what is to be true?

Pressure should be less in lungs than atmosphere

What happens in the three stages of Air Flow

1. At Rest: Diaphragm is relaxed

2. Inspiration: Thoracic Volume increases

3. Expiration: Diaphragm relaxes, thoracic volume decreases

What is the atmospheric pressure

0 mm Hg

What causes the decrease in pressure during the beginning of a respiratory cycle?

An increase in lung volume

With the pressure change diagram, how are the changes in volume determined?

When pressure decreases, the volume inside the lung also decreases

How are thoracic cavity helping lungs

they move to help them contract and expand

Where is the visceral pleura and parietal pleura

Inner sac of lungs and outer sac of lungs

What is the subatmospheric pressure?

-3 mm Hg

Which way will air flow if you have a punctured lung?

Air will flow into the pleural space

What does a puncture do to the lung?

The fluid breaks

What does most of the work in breathing lead to

Overcoming resistance of lungs and thoracic cage to stretching

What is compliance?

Ability of lungs to stretch when pressure is added

(Force needed to deform a body)

High Compliance means what related to stretching

Means it stretches easier

What is elastance (elastic recoil)

Ability to resist deformation

Body to return to original shape when deformed

What sort of elastance and compliance would a plastic supermarket bag have?

Low elastance

High compliance

What are alveoli coated with

Thin Layer of Saline solution

Why does the saline solution exhibit surface tension

Due to the presence of hydrogen bonds in water (Creates pressure pushing in towards the center)

What is the Law of Laplace?

Pressure in bubble is directly proportional to surface tension of fluid and inversely proportional to radius of bubble

What do cells in the alveoli secrete

Surfactant

What cells in the alveoli secrete surfactant?

Type II alveolar cells (5%)

What does surfactant do?

Breaks up water molecules to decrease surface tension

How does decreasing surface tension affect the pressure in a bubble?

Pressure decreases

What are surfactants made out of?

Proteins and Phospholipids

Where does most airway resistance come from

Trachea and Bronchi (Rigid)

Mucus could also

What is notable about bronchioles during airway resistance?

Collapsible>Level of autonomic control>bronco constriction and can be effected by epinephrine

What is the total pulmonary ventilation

Volume of air moved to and out of lungs

How is total pulmonary ventilation measured?

Ventilation Rate (Breaths per minute) x Tidal Volume

Why does some of the air that enters the respiratory system does not reach the alveoli

Every breath remains in the airways

What is the respiratory cycle?

A cycle of fresh air and stale air

Even though the average tidal volume is 500, how much fresh air do we get

350 mL

What is the more accurate way to get ventilation efficiency?

Alveolar Ventilation

What is the equation for Alveolar Ventilation

AV=Ventilation Rate x (Vt-Vo)

What is needed in the transport between capillary and alveoli?

Ventilation rate match blood flow

How does ventilation rate match blood flow

1. Capillaries in the lungs are collapsible

What are arterioles sensitive to

Oxygen

What are bronchioles more sensitive to

Carbon Dioxide