Life support

How long can you live without...

• Eating?• Drinking?• Breathing?• Your heart beating?

How long can you live without...

• Eating? ~4 – 6 weeks• Drinking? ~ 3 days• Breathing? ~4 – 5 minutes• Your heart beating? ~about 4 minutes

How can we support life?

How can we support life?

• Drips• Feeding tubes• Oxygen masks• Ventilators

Is switching off life support murder?

Is it humane to continue life if a person is suffering and in pain?

Is it humane to continue someone’s life who has no chance for a reasonable life?

Is it humane to continue life if a person has no way to consent to treatment?

Who decides?

Positives and Negatives

What benefit to the individual or society?

What costs to individual or society?

Martha Mason of Lattimore, North Carolina died on May 4, 2009, after spending 60 of her 72 years in an

iron lung.

Coma Miracle

Premature Baby’s First Few Minutes

Respiratory System

Function

• To exchange gases with the surrounding environment O2 in CO2 out

Control Mechanism• CO2 is a waste product

of the cells

• CO2 makes carbonic acid in the blood (changes pH)

• The medulla oblongata keeps track of pH, controls breathing

Organ Overview

• Mouth, Nose• Epiglottis (stops foood

entering trachea)• Trachea (wind pipe)• Bronchus (branch)• Bronchioles (little branches)• Alveoli

Nose and Mouth

• Humidifies and warms air

Lung Protection

• Mucous –sticky to trap dirt and bacteria

• Cilia (little hairs) to– Filter dirt/bacteria– Remove dirt/bacteria

with their wave action

Epiglottis

• Flap of cartilage• Covers trachea

when eatingto prevent foodfrom entering

Trachea

• A large tube supported from collapse by rings of cartilage.

Bronchi

• two, one going to each lung• similar structure to the

trachea with cartilage rings

Respiration 3D

Alveoli (pl)

• Site of gas exchange• We have ~ 300 million• Surface area equivalent

to a tennis court!• Capillaries surround

each alveolus.

How does it work?

• Lungs are not muscles• Diaphragm is a muscle– Diaphragm contracts– Ribcage expands– Lungs expand– Air rushes in to fill up

empty space

How does it work?

• Exhaling is generally a passive process– Diaphragm relaxes – Lungs compress– Forces out air

• You can also use the muscles around your ribcage to constrict your chest more, expelling more air

Diffusion

• Gases move from high concentration to low concentration.

Diffusion

When good lungs go bad...

Bronchitis – narrowed bronchiolesEmphysema – alveoli walls broken down

Pneumonia

Intubation

Cardiopulmonary Respiration