Smoking and what effects it has on you.

So what does a regular cigarette

• tar
• butane
• ammonia
• methanol
• formoladehyde
• cadmium
• radon
• hydrogen Cyanide
• arsenic
• acetone
• nicotine
• carbon monoxide

Carbon monoxide

• carbon monoxide enters the blood and combines with the red blood cells haemoglobin to form carboxyhemoglobin
• reduces the oxygen capacity of RBC
• smokers feel this when they exercise
•  also damages the endothelium of the arteries

Damaged arteries can lead to artherosclerosis

• damage is repaired by the phagocytes
• this encourages the growth of smooth muscle
• this leads to deposition of fatty substances (plaque)
• these deposits develop into atheromas

The build up of Artheroma’s results in tears and restriction of the lumen and the blood flow

This can lead to many conditions such as Thrombosis, coronary heart disease and strokes. These are all types of cardiovascular disease.

thrombosis

• blood flowing past a built up plaque cannot flow smoothly
• this can lead to a blood clot forming, which increases the risk of sticky platelets
• blood clot is a thrombus
• it can block arteries

CHD

when the lumen of the coronary arteries is narrowed by plaque, it can reduce the blood flow to the heart, which can result in:

• Heart attack, where part of the heart muscle dies
• Angina: Severe pain in chest as heart does not receive enough O2
• heart failure: where the heart cannot pump due to blockage of CA

So what factors increase the risk of CHD?

•Age.

•Sex (men under 50 much more likely to die than women).

•Smoking.

•Obesity.

•Hypertension.

•High blood cholesterol.

•Lack of exercise.

•General diet, inc. high salt intake.

•Genetic.

•Diabetes.

•Stress.

Stroke

• Death of brain tissue
• caused by either thrombus blocks an artery leading to the brain
• artery leading to brain burst (haemorrhage)

 

cardiovascular diseases are those diseases that affects the heart and circulatory system.

• Atherosclerosis
• Coronary heart disease (CHD)
• stroke
• arteriosclerosis

This disease is the most common that affects the economically developed countries.

Symptoms of Cardiovascular disease:

High blood pressure and hypertension are usually the first signs, they result from the narrowing of the artery lumen caused by the deposition of atheroma. The narrowing lumen increases the friction between the blood and the artery wall. The heart pumps against this increase friction between the blood and the artery wall. The heart pumps against this increased friction which raises the blood pressure. The atheroma makes the artery wall less elastic. WHich means that they cannot recoil and dilate as easily.

Coronary heart disease (CHD)

A person with CHD may find it more harder to exercise. They may feel out of breath after only a small amount of exertion. This is because of the atherosclerosis in the coronary arteries. The atheroma narrows the lumen of the artery, reducing blood flow to the cardiac muscle. When exercising the heart increases its output. The heart muscle does not receive enough oxygen for aerobic respiration and is put under strain in an effort to pump more blood. As it does not have enough oxygen it cannot pump sufficient blood to the rest of the body.

stroke

The symptoms of stroke are always sudden, it results from part of the brain receiving not enough oxygen

• sudden numbness or weakness of the face, especially on one side of the body
• sudden confusion and difficulty in speaking or understanding
• sudden difficulty in seeing
• sudden trouble in walking
• sudden severe headache, unknown causes

Nicotine mimics the action of transmitter substances between nerves, making the nervous system more sensitive, Nicotine causes adrenaline to be release, this increased Adrenaline can cause:

• increased heart rate
• breathing
• arterioles constrict
• raise blood pressure

Nicotine causes the arterioles to constrict. It can make platelets sticky which can contribute to the formation of clots and thrombus. and also causes the build up of plaque. A clot or thrombus can stop blood flow. Or move in blood until it reaches a narrow artery.

Short term affects that result from TAR

Tar is a combination of chemicals which end up settling on the lining of the airways and the alveoli and NOT in the blood, it is said to be carcinogenic.

• Because it settles on the lining of the airways and the alveoli, it increases the diffusion distance for oxygen entering the blood and for carbon dioxide leaving the blood.
• Results in smooth muscles in the walls of the airways to contract
• the lumen of the airway gets smaller and this restricts the flow of air to the alveoli
• cilia are unable to move the mucus
• tar also stimulates goblet cells to enlarge and secrete more mucus
• mucus collects in airways, pathogens are not removed, so multiply
• bronchioles become blocked and more susceptible to infections

Long term effects of tar

Smokers cough is an attempt to move the bacteria laden mucus that collects on the lungs. A constant cough can lead to the delicate lining of the airways and the alveoli becoming damaged. This lining will eventually be replaced by scar tissue, which is thicker and less flexible. More smooth muscle grows on the bronchioles which reduces the lumen of the airway and the flow of air is permanently restricted.

Due to the build up of the pathogens in the bronchioles, means that the linings of the airways may become inflamed, this will damage the lining of the epithelium in particular. Also this then attracts white bloods cells which attempt to deal with the pathogenic micro-organisms. They have to make their way into the airway from the blood, so therefore they release enzymes which digest part of the linings of the lungs in order to get into the airways. The enzyme used is elastase. This damages the elastic tissue in the alveoli, so they alveoli can no longer contract and expel air as there is a loss of elasticity in the alveolus walls. As we exhale, the alveolus walls do not recoil to push air out. Which increases pressure in the alveoli as air gets trapped. The bronchioles collapse which cause the alveoli to burst and therefore reduce the surface area of the lungs.

Diseases associated with smoking

Emphysema

• loss of elasticity in the alveoli, which causes it to burst
• reduction in surface area, so less surface for gaseous exchange
• shortness of breath which leads to more shallow and rapid breathing
• blood is less well oxygenated which leads to fatigue

Lung cancer

• carcinogenic compounds line the lungs
• these chemicals (mutagens) enter nucleus and cause mutation of DNA which can effect cell division
• Cancer often starts at the entrance of the bronchi and takes 20-30 years to develop and grows for years before it develops

Chronic bronchitis

inflammation of the lining of the airways and damage to the cilia and over production of mucus by goblet cells

• irritation of the lungs
• coughing
• coughing up bacteria-laden mucus that will also contain white blood cells
• can lead to infections

Chronic obstructive pulmonary disease

this is a combination of all the diseases mentioned above

Evolution: Variation

variation is the presence of variety

• variation within a species
• variation between a species

Examples of human variation can include:

• eye colour
• hair colour
• skin colour
• nose shape

There are 2 types of variation within species, it is continuous and discontinuous
variation.

Continuous variation:

• 2 extremes to the variation
• fill range of values between those extremes
• most individuals are close to the mean value
• there are a few individuals at the extreme values
• tends to be quantitative
• controlled by a lot of genes
• strongly influenced by the environment

 

discontinuous variation

• is where the data has 2 or more distinct categories
• it is either one thing or another
• it is not in between and has no intermediate values
• the members of the species can be evenly distributed between the forms
• controlled by a few genes
• unaffected by the environment

 

Variation can be caused by the environment and genetics

we inherit genes. We have alleles for a characteristic, human cells contain approx 25,000 genes, many of these genes will have more than one allele. Environmental factors such as obesity in humans and a persons skin colour,height, direction of growth, amount of growth

 

Business significance of XED, PES, PED and YED

PED

PED is widely used by businesses when pricing their products in the market. It is most common with business where market segmentation is based on time, such as transport and leisure. Train operators for example seek to maximise profits by charging for peak and off peak, where demand will vary.

If Demand is inelastic then train operators can increase the price and their revenue would increase, however if a company such as Sony raised the price of their playstation 3 then demand would fall and revenue would decrease, this is because demand is elastic as there are close substitutes available such as the Xbox 360.

YED

Over time most products tend to become income elastic, this is because the standards are always improving so income tends to increase. Firms with Inferior products would suffer because of this and would aim to make their elasticity positive in order to survive their market.YED can be used by businesses to forcecast future demand

XED

Firms competing in markets with close substitutes would be looking at the XED very carefully. this maybe in order to steal market share, for example by lowering their prices, which would increase their revenue, however increasing prices in a competitive market would be dangerous as it is more likely that revenue would be lost.

Complements also come into consideration, for example if the price of strawberries increased, then the demand for whipped cream would decrease, this can effect businesses that supply both of these products.

PES

PES is always positive. In the short term supply tends to be inelastic as it is difficult to shift the resources into a market, however firms can hold stocks to cope with the sudden change in demand, making it supply elastic, they may hold onto stock in anticipation of a price rise.

An example would be tuna in America, the supply elasticity was 0.2, this meant that supply was not very responsive to a change in demand, hence it was inelelastic. However demand for tuna increased, as the health benefits were made obvious, because it was inelastic, price increased in the US market as a result.

Tissues in the lungs

The trachea, bronchi and bronchioles are airways that allow passage of air into the lungs and out again. To be effective, these airways must meet certain requirements:

• the larger airways must be large enough to allow sufficient air to flow through without obstruction
• they must also divide into smaller airways to reach the alveoli
• the airways must be strong enough to prevent it from collapsing when the air pressure inside is low (which occurs during inhalation)
• they must be flexible to allow movement
• they must also be able to stretch and recoil

The trachea and the Bronchi

These both have a similar structure. They differ only in size. The Bronchi are narrower than the trachea They have relatively thick walls that have several layers of tissue

• much of the wall consists of cartilage
• the cartilage is in the form of incomplete C shaped rings in the trachea, however it is less regular in the bronchi
• on the surface of the cartilage is a layer of glandular tissue, connective tissue, elastic fibres, smooth muscles and blood vessels. It is often called the “loose tissue”
• The inner lining is an epithelium layer that has two types of cell. Most of the cells have cilia. This is called the ciliated epithelium. Among the ciliated cells are goblet cells.

Bronchioles

They are much narrower than the bronchi. The larger Bronchioles may have some cartilage, but smaller ones do not have cartilage. the wall is made mainly of smooth muscle and elastic fibres. The smallest bronchioles have clusters of alveoli at their ends

 

The role of each tissue

Cartilage

• It plays a structural role
• it supports the trachea and the bronchi, this prevents the collapse when the air pressure inside is low during inhalation
• it does not form a complete ring, so there is some flexibility, so you can move your neck without constraining the airways
• It allows the oesophagus to expand during swallowing

Smooth muscle

• it can contract
• when it contracts, it constricts the airways
• when the airway is constricted, the lumen of the airway becomes narrower
• constricting the lumen can restrict the movement of air to and from the alveoli, this is most common in the bronchioles

Elastic fibres

• when the airway contracts, the diameter of the lumen is reduced
• the smooth muscle cannot reverse this effect
• when the airway constricts, it deforms the elastic fibres in the loose tissue
• as the smooth muscle relaxes, the elastic fibres recoil and return to their original shape, this dilates the airway

goblet tissues and glandular tissues

• these secret mucus
• the mucus traps tiny particles from the air, these particles may include pollen and bacteria
• trapping the bacteria so that they can be removed can reduce the risk of infection

 ciliated epithelium

• these consists of ciliated cells, they have numerous tiny, hair like structures projecting from their membrane, they are known as cilia
• Cilia moves in a synchronised pattern to waft mucus up the airway to the back of the throat. Once there the mucus is swallowed and the acidity in the stomach would kill any bacteria.

The lungs as an organ of exchange

The lungs

these are a large pair of inflatable structures lying in the chest cavity. Air can pass through the nose and along the trachea, Bronchi and Bronchioles. Each part of this airway is adapted to its function of allowing the passage of air. Finally the air reaches the surface of the  Alveoli. The walls of the Alveoli are the surface where exchanges of gases take place.

The lungs are protected by ribs. Movement of both the ribs and the diaphragm helps to produce breathing movements known as ventilation

Gaseous exchanges/how the lungs are adapted

Gases pass both ways through the thin walls of the Alveoli. Oxygen passes from the air in the Alveoli to the blood in the capillaries  Carbon dioxide pass from the blood to the air in the Alveoli.

• the large surface area provides more space for molecules to pass through. The individual Alveoli are very small (about 100-300Micrometers across). They are so numerous that the total surface area is larger than our skin. The total surface area of the lung exchange surface is about 70m(squared)
• A barrier permeable to oxygen and carbon dioxide means that plasma membranes that surround the thin cytoplasm form the barrier for exchange. These allow the diffusion of co2 and o2
• The thin barrier to reduce the diffusion distance has a number of adaptations to reduce the distance that gases have to diffuse

1. The alveolus wall is one cell thick
2. the capillary wall is one cell thick
3. both walls consist of squamous cells- this means flattened or very thin cells
4. The capillaries are in close contact with the Alveolus walls
5. The capillaries are so narrow that the blood cells are squeezed against the capillary wall, making them closer to the air in the alveoli, reducing the rate that it flows past in the blood
6. the barrier of diffusion is only 2 flattened cells thick, and is less than 1 micrometer thick.

A thin layer of moisture surround the alveoli. This moisture passes through the cell membranes from the cytoplasm of the alveolus cells. As we breathe out, it evaporates and is lost. The lungs must produce a substance called a surfactant, that reduces the cohesion between the water molecules. Without the surfactant, the alveolus would collapse due to the cohesive forces between the water molecules lining the air sac.

 

Maintaining a diffusion gradient

For diffusion to be rapid, a steep diffusion gradient is needed. This means having a high concentration of molecules on the supply side of the exchange surface, and a low concentration on the demand side.

To maintain the diffusion gradient, a fresh supply of molecules on one side is needed to keep the concentration high, and a way of removing the molecules from the other side is needed to keep the concentration low

This is achieved by the action of the blood transport system and the ventilation movements

The blood brings carbon dioxide from the tissue to the lungs. This ensures that the concentration of carbon dioxide in the blood is higher than in the alveoli air space. It also carries oxygen away from the lungs. This ensures that the concentration of oxygen in the blood is kept lower than the concentration than the air inside the alveoli.

The heart pumps blood along the pulmonary artery to the lungs. In the lungs the artery divides up to form finer and finer vessels. These eventually carry blood in tiny capillaries that are only just big enough for a red blood cell to squeeze through. These capillaries lie over the surface of the alveoli.

The breathing movements of the lungs helps to ventilate the lungs. They replace the used air with fresh air. This brings more oxygen in the lungs and ensures that the concentration of oxygen in the air of the alveoli remains higher than the concentration of oxygen in the blood.

The constant supply of gas to one side of the exchange surface and the removal from the other side ensures that diffusion, and therefore exchange can continue.

 

Inhaling

1. The Diaphragm contracts and moves upwards
2. The rib cage external intercostal muscles contract to move ribs upwards and outwards
3. The volume of the thorax increases
4. The pressure in the lungs falls below atmospheric pressure so air moves in

Exhaling

1. The Diaphragm relaxes and moves upwards
   
2. the ribcage external intercostal muscles relax so that the ribs move down and inwards
3. the volume of the thorax decreases
4. the pressure in the lungs rises above that of atmospheric pressure so air moves out