human biology (biol 104) talk eight: the respiratory system chapter 10 and drug addiction (not in...

Human Biology (BIOL 104)

Talk Eight:

The Respiratory System

Chapter 10

And Drug Addiction(Not in book)

The Respiratory System• Works in conjunction with the Human

Cardiovascular System:

• For RESPIRATION to occur

• Breathing –air in and out of lungs

• External respiration –exchange of gasses between air and the blood

• Internal respiration – exchange between blood and tissue fluid

• Cellular respiration –production of ATP in cells


• Basic functions of the respiratory system

• Breathing • (Pulmonary Ventilation)

– movement of air in and out of the lungs

• Inhalation (inspiration) – draws gases into the lungs.

• Exhalation (expiration) – forces gases out of the lungs.

Copyright ©The McGraw-Hill Companies; used with permission

The Respiratory System– Gas Conditioning – as gases

pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent.

– The gases in the air are: • warmed to body

temperature• humidified• cleaned of particulate

matter

– Gas Exchange - respiration• Supplies body with

oxygen• Disposes of carbon

dioxide

– Produces Sounds

– Protects respiratory surfaces

– Site for olfactory sensation


The Respiratory System• Two parts:• Upper Respiratory Tract• Nasal Cavities

– Filter, warm and moisten air

• Pharynx– Connection to

surrounding regions• Glottis

– Passage of air into larynx

• Larynx– Sound production

The Respiratory System• Lower Respiratory Tract• Trachea

– Passage of air to Bronchi

• Bronchi– Passage of air to lungs

• Bronchioles– Passage of air to each

alveolus

• Lungs– Gas Exchange

The Larynx• This serves as a passageway

for air between the pharynx and the trachea.

• The larynx houses the vocal cords – Mucosal folds suspended by

elastic filaments stretched across the glottis.• Air moves through

glottis – vibration – sounds

• The trachea is a tube connecting the larynx to the primary bronchi.

The Trachea• Windpipe – connects

larynx to primary bronchi.

• Held open by cartilage

• Goblet cell– Makes mucus

• Mucosa contains layer of pseudostratified ciliated epithelium– Sweep dirt and excess

mucus upwards

Bronchi in the Conducting Zone• Consists of:

– Respiratory muscles – diaphragm and other muscles that promote ventilation

– Respiratory zone – site of external respiration – respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

– Conducting zones• Provides rigid conduits for

air to reach the sites of gas exchange

• Includes nose, nasal cavity, pharynx, trachea

• Air passages undergo 23 orders of branching in the lungs


Bronchi in the Conducting Zone• Bronchial tree - extensively

branching respiratory passageways– Primary bronchi (main

bronchi)• Largest bronchi • Right main bronchi - wider

and shorter than the left

– Secondary (lobar) bronchi • Three on the right • Two on the left

– Tertiary (segmental) bronchi - branch into each lung segment

– Bronchioles - little bronchi, less than 1 mm in diameter

– Terminal bronchioles - less than 0.5 mm in diameter


The Lungs• These lie on either side of the

heart within the thoracic cavity.

• Total cross-sectional area of 50 – 70 meter squared (1 ½ Tennis courts)– Right lung has three lobes

and the left lung has two lobes.• This allows room for

the heart

– Each lobe is divided into lobules, further divided into bronchioles serving many alveoli.


The Lungs

Features of Alveoli• Alveoli cell types

– Type I cells site of gas exchange

– Type II cells - secrete surfactant

– Macrophages

• Surrounded by basal laminae and elastic fibers• Interconnect by way of alveolar pores• Internal surfaces - site for free movement of alveolar macrophages


• Bronchial “tree” and Associated

Pulmonary arteries

• A very complex network of airways and blood vessels in the lungs to support gas exchange.

• There are 300 million alveoli per set of lungs.

• Each one is made up of squamous epithelium and blood capillaries.

• Gas exchange occurs: O2 diffuses across the alveolar wall and enters blood – CO2 goes in other direction.



Alveoli- site of gas exchange• External respiration refers to gas

exchange between air in the alveoli and blood in the pulmonary capillaries.

• Blood entering the pulmonary capillaries has a HIGHER partial pressure of CO2 than atmospheric air.

• CO2 diffuses out of the blood into the lungs.

• Carried in blood plasma as bicarbonate ions (HC03 ions)

• Blood entering the pulmonary capillaries has a LOWER partial pressure of O2 than the avlvoli.

• O2 diffuses into plasma and then red blood cells

• Binds with hemoglobin – forms oxyhemoglobin


Alveoli- site of gas exchange• Internal respiration - gas exchange

between the blood in systemic capillaries and the tissue fluid.

• O2 diffuses out of the blood into the tissue because the partial pressure of O2 in tissue fluid is LOWER than that of blood.

• O2 leaves hemoglobin and enters tissue fluid

• CO2 diffuses into the blood from the tissue because the partial pressure of CO2 in tissue fluid is HIGHER than that of blood

• CO2 combines with H20 – forms carbonic acid. Some binds to hemoglobin – forms carbaminohemoglobin


Pulmonary Ventilation (breathing)

• Inspiration: due to contraction of: – diaphragm– intercostal muscles (both

external & internal, costal nerves)

– Expanding the thorax reduces pressure within the lungs (you don’t “suck in air”…you “vacuum” it)

• Expiration: relaxation of muscles– Recoil of elastic fibers in

tissue– Allows costovertebral joint

to return to original position• As lungs constrict,

surfactant prevents alveolar collapse

Mechanism of Breathing• Respiratory Volumes

– Tidal volume is the amount of air that moves in and out with each breath.

– Vital capacity is the maximum amount of air that can be moved out in a single breath.• Inspiration can be

increased by expanding the chest (inspiratory reserve volume).

– Residual volume is the air remaining in the lungs after deep exhalation.


Breathing at High Altitude

• At sea level, because air is compressible, the weight of all that air above us compresses the air around us, making it denser.

• As you go up a mountain, the air becomes less compressed and is therefore thinner.

• The important effect of this decrease in pressure is this: – in a given volume of air, there

are fewer molecules present. This is really just another way of saying that the pressure is lower (this is called Boyle's law).

This bottle was photographed at 3600m (left) then again at sea level

(right)

Breathing at High Altitude• The percentage of those

molecules that are oxygen is exactly the same: 21%.

• The problem is that there are fewer molecules of everything present, including oxygen.

• So although the percentage of oxygen in the atmosphere is the same, the thinner air means there is less oxygen to breathe.

This bottle was photographed at 3600m (left) then again at sea level

(right)


• The function of the lungs is to expose blood to fresh air, and breathing faster essentially increases the flow of fresh air past the blood.

• This means that whenever an oxygen molecule is taken away by the blood, it is quickly replaced by another one.

• Carbon dioxide (CO2) is constantly produced by the body and the lungs remove it by allowing it to diffuse into the fresh air in the lungs.

• Increasing the flow of fresh air through the lungs, by hyperventilating, increases the rate at which CO2 is lost.


• Because CO2 is an acid gas, losing more of it from the blood leaves the blood relatively alkaline.

• At altitudes up to about 6000m, the kidneys correct the alkalinity of the blood over a few days by removing alkali (in the form of bicarbonate ions, HCO3) from the blood.

• When the blood passing through an area of lung isn’t picking up enough oxygen, the blood vessels carrying that blood tighten, so that less deoxygenated blood can get through the lungs.

• This is called hypoxic pulmonary vasoconstriction. – means that less deoxygenated blood

gets through, so there is more oxygen in the mixture of blood leaving the lungs.

Non-respiratory Air Movements

• Coughing: deep inspiration, closure of the glottis, followed by strong expulsion that forces open the glottis

• • Sneeze: = air exits via nasal cavity rather than oral

cavity

• Yawn: = deep inspiration, pause, sudden expiration

• Laugh: = deep inspiration followed by sudden & rapid expirations

• Crying: is very similar, but glottis remains open the entire time…why you often choke when you cry

• Hiccup: = spastic diaphragm contractions

Drugs and addiction

Important but NOT in book

Drugs and addiction• Drug addiction is a condition

characterized by compulsive drug intake, craving and seeking, despite negative consequences associated with drug use.

• The activity of any drug varies with dose– The amount of the drug

taken over time

• The amount of a drug taken to be toxic or lethal depends upon the chemical structure of the drug– Also body size and other

physiological variables

From Wikimedia Commons, a freely licensed media file repository

How drugs enter the body

• In the US, most drugs are inhaled and quickly enter the blood system and affect the brain.

• However, it is important to remember that the most popular drug in the US is caffeine!

• The second is alcohol!

• It is important to remember what is a drug!


Drugs and addiction

• Although being addicted implies drug dependence, it is possible to be dependent on a drug without being addicted.

• People that take drugs to treat diseases and disorders, which interfere with their ability to function, may experience improvement of their condition.


How drugs enter the body• The way in which a drug

enters the body often affects its resulting concentration in body tissues.

• Example: Cocaine – A product of the coca plant –

grows in the high Andes

• Cocaine exists in many forms that differ in both conc of the drug and its molecular form.

• Coca leaves are chewed by South American Indians– Concentrations absorbed

by the gut are low.



• By contrast:

• When cocaine is purified into a powder and sniffed the rate and concentration of absorption is increased many times.

– Cocaine is sometimes further purified into crack

• Whether cocaine is sniffed or smoked, it is inhaled not as a gas, but as small particles

• For these chemicals to be absorbed they must first adhere to lung tissue.



• Other drugs are injected into the body.

• Can be injected into veins, or under the skin

• Continued uses always leads to infection and amputation of damaged tissue.


How drugs enter the body• Chemicals can be highly

concentrated within a particle

• Thus these particles cause substantial damage to lung tissue

• Sniffing cocaine powder also causes substantial damage to cells in the nasal passage and rot a person nose

• Can also eat away at the roof of the mouth.


Addiction• Addiction has been defined as

– “Compulsive physiological and psychological need for a substance”

• This implies there is both a biological basis and a mental basis for addiction.

• However, as all brain function is biochemically based, the distinction between physiological and psychological addiction is becoming blurred.

Addiction• Ventral tegmental area (VTA)

– Thought to be positive enforcement area (pleasure center).

– Experiments on rats and rhesus monkeys have show that both would rather electrically stimulate this area of the brain than eat – even if near to starvation

• Nucleus accumbens (NA)– joined to the VTA by synaptic

connections

– Interprets the stimulation signal from the VTA

Addiction• Frontal cortex (FC)

– Play a part in impulse control, judgment, language production, working memory, motor function, problem solving, sexual behavior, socialization and spontaneity.

– Assist in planning, coordinating, controlling and executing behavior.

– This is why behavioral changes occur which are hard to break.

Addiction• So these positive

reinforcement areas are affected by drugs

• Amphetamines indirectly stimulate the neurons of the VTA– Used as a treatment for

depression

• Cocaine acts on the brain cells of the VTA that secrete dopamine– Produces euphoria.

Addiction• Opiates, marijuana, caffeine,

and alcohol all produce VTA self-reinforcing effects.

• Drugs of abuse take over the neuronal circuitry involved in motivation and reward, leading to altered engagement of learning processes.

• Because of this, drug-associated cues can trigger cravings as well as unconcious or compulsive drug-seeking behavior, with the sense that voluntary control over drug use is lost.

Addiction• The stages of problematic use could be defined

as Pre-occupation/anticipation, binge/intoxication & withdrawal/negative effect

• As drugs activate neuronal pathways in the brain we effectivly learn to use them, these pathways in the brain not only get 'laid down' stronger and stronger with sucessive use but also activate faster– the quicker the effect or 'high' the stronger

this dysfunctional learning.

Addiction

• Objects, people or places also seem to to be strongly associated with the drug experience, making them 'Triggers' to 'Cravings' – increase the chances of further use.

• Animal studies have shown drug availabilty over and above the actual effects of the substance) are associated with stimuli, exposure to objects associated with use trigger the release of adrenaline (Fight or flight) – this excitation can be perceived as a 'need' to

use.

Addiction• Users in addictive

drugs in the US in 1991

• The top three are widely not considered drugs by most of the population

• All of these three produce addictive behavior.

METH• Methamphetamine or “Meth”, a derivative of

amphetamine is an extremely powerful stimulant that affects the central nervous system.

• Developed in 1919 by Japanese pharmacologist.

• Although its initial uses were for medical purposes, its ability to increase energy and to enable users to function without sleep made it attractive for military purposes during World War II.

METH• Meth has undergone both legal and illegal uses

in the United States. – As early as the 1930s it was used

therapeutically to treat asthma and epileptic seizures

– In the 1950s it was given to housewives to cope with bordem and depression

– During the 1970s meth was a primary appetite suppressant in prescription diet pills.

• The illicit demand for meth resulted in forged prescriptions, theft and a black market.

METH labs• How is Meth Made?

– ephedrine reduction.

• In this process, ephedrine or psuedoephedrine are chemically extract from over the counter cold medicines.

• Red phosphorous (match tips), iodine (table salt), acetone (nail varnish remover), and sulphuric acid (car battery) are all that is required.

METH labs• Lastly, drain cleaner,

camping fuel and paint thinner are used to dry out the drug into a powder.

• Clandestine labs are often simple, crude and consist of common household items.

• Meth can be cooked in basements, old buildings, motel rooms, camping trailers and moving

vehicles.

How to tell if Someone is on or has been using Meth

• Meth affects nerve endings throughout a user's body.

• Many people feel a sensation of small bugs, known as "Meth Mites", moving right under their skin.

• They scratch, pick and dig the spots, trying to relieve the itching.

• The Meth Mites and the scratching result in sores and serious infections. From Wikimedia Commons, a freely

licensed media file repository


• The heated substance, when fully aspirated, swirls through the users' teeth and gums, inevitably leading to sores which never heal -Meth Mouth

• Tooth enamel wears away quickly as entire rows of teeth dissolve to the gum line.

• Collects in the nasal passages which drain in the back of the throat, effectively corroding your entire face. From Wikimedia Commons, a freely

licensed media file repository


• Chronic meth users are typically gaunt, maintain poor hygiene.

• Lose interesting in eating– Digestive system shuts

down due to chemicals used to make meth

• Kidney and liver shut down– Due to all the toxic

chemicals

• Skin scratched off, infections

• Blindness.


Environmental Damage

• Each pound of meth produced leaves behind five-seven pounds of toxic waste.

• Toxic byproduct is often poured down drains or directly into the ground, creating long term hazards.

• Mobile labs and meth lab dump-sites are found threaten our state’s natural resources.

• Clean-up costs range from $5,000 to $50,000..5,000-$50,000

The End!

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