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Diseases of the heart and circulatory system

Khan: heart diseases and heart attacks

http://www.khanacademy.org/video/heart-disease-and-heart- attacks?playlist=Biology

Khan: thrombo-emboli and thromboembolisms

http://www.khanacademy.org/video/thrombo-emboli-and- thromboembolisms?playlist=Biology

Khan: stenosis, ischemia and heart failure

http://www.khanacademy.org/video/stenosis--ischemia-and-heart- failure?playlist=Biology

Cardiovascular diseases

  • Cardiovascular disorders are a major cause of death in modern societies like heart attacks and strokes .
  • Angina is caused when the heart muscle receives an inadequate supply of blood, resulting in very painful cramps in the chest area.

Heart attack

Cardiac muscle cells are provided with oxygenated blood by a system of coronary arteries . During exercise the flow through these arteries is up to five times normal flow. Blocked flow in coronary arteries can result in death of heart muscle, leadingto a heart attack .

Blockage of coronary arteries is usually the result of gradual buildup of lipids and cholesterol in the inner wall of the coronary artery. Occasional chest paincan result during periods of stress or physical exercise. Angina indicates that oxygen needs are greater than the ability to deliver it and that a heart attack may occur in the future. Heart muscle cells that die are notreplaced since heart muscle cells do not divide. Heart disease and coronary artery disease are the leading causes of death.

The figure below shows development of arterial plaque. Images from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ), used with permission.

Hypertension

Hypertension , high blood pressure (the silent killer), occurs when blood pressure is consistently above 140/90. Causes in most cases are unknown, although stress, obesity, high salt intake,and smoking can add to a genetic tendency. Luckily, when diagnosed, the condition is usually treatable with medicines and diet and exercise

Stroke

What Is a Stroke? What Causes a Stroke?

A stroke is a condition where a blood clot or burst artery or blood vessel interrupts blood flow to an area of the brain. A lack of oxygen and glucose (sugar)flowing to the brain leads to the death of brain cells and brain damage, often resulting in an impairment in speech, movement, and memory.

The outcome after a stroke depends on where the stroke occurs and how much of the brain is affected. Smaller strokes may result in small problems, such as weakness in an arm or leg. Larger strokes may lead to paralysis or death. Many stroke patients are left with weakness on one side of the body, difficulty speaking, and bladder problems.

Questions & Answers

important of enocomic
Adu Reply
what is division of labour
Dennis Reply
division of labour can be defined as the separation of task to individuals in any economic system to specialize on it.
Ahmad
what is demand curve
Victoria Reply
demand curve is a downward sloping economic graph that shows the relationship between the price of product and the quantity of the product demanded.
Ahmad
What is demand
Frank Reply
It refers to the quantity of a commodity purchased in the market at a price and at a point of time.
Basanta
refers to amount of commodities a consumer is willing and able to buy at particular price within a period of time
Clifford
It is the ability and willingness a customer buys a product or service at a particular price, place and time while other things remaining constant or the same
kum
In which case is opportunity cost is zero
Francis Reply
where no alternative is available
Bhartendu
who is the father of economic
Omar Reply
Adam Smith
Suraj
ok
Tony
Adam Smith
Francis
Adam smith
Opana
Adam Smith
Basanta
What is monopoly
Mauthoor Reply
it an economic situation where one individual controls the essential commodities or value product for maximum profit
James
monopoly is a market situation in which there is only one producer of a good or service which has no close substitutes
eliano
is where only one person is solely the price taker
Francis
what is Monopoly
Dauda Reply
The word Monopoly is a Latin word. it is the combination of two words-Mono means single and Poly means seller. thus Monopoly means single seller. but this is not the full meaning of Monopoly. Monopoly must produce a product which does not have close substitute in the market.
Basanta
Monopoly is define as a firm in an industry with very high barriers to entry.
Favour
If close substitute is available, Monopoly will be a king without a crown.
Basanta
what does it array
Cbdishakur Reply
what are the differences between monopoly and.oligopoly
Onome Reply
what are the difference between monopoly and oligopoly
Cbdishakur
The deference between Monopoly and Oligopoly: Monopoly means:A single-firm-Industry producing and selling a product having no close business and Oligopoly means:A market structure where a few sellers compete with each other and each controls a significant portion of market .
Basanta
so that the price-output policy one affects the other.
Basanta
what are difference between physical policy and monotory policy
hon
what is economic
Emakpor Reply
what is economic
Cbdishakur
the word economic was derived from the Greek word oikos (a house)and mein(to manage) which in effect meant managing a household with the limited funds available 🙂.
Basanta
good excample about scarsity
hon
An Enquiry into the nature and causes of wealth Nations, this book clearly defined what economic is🙂🙂🙏🙏 thank you...
Basanta
good example about scarcity: money,time, energy, human or natural resources. Scarcity of resources implies that there supply is very much limited in relation to demand.
Basanta
equilibrium is a situation in which economic forces such as demand and supply are balanced and in the absence of external influences,the value of economic variables will not change
Onome Reply
hmnn
Emakpor
marginal cost and marginal revenue is equilibrium .
Kho
yessss
Basanta
what is equilibrium
Rodrice Reply
policy prescriptions for unemployment
Jeslyne Reply
Am working on it
Blacks
Study
Janelle
study
simeon
what are the factors effecting demand sedule
Kalimu Reply
we should talk about more important topics, you can search it on Google n u will find your answer we should try to focus on how we can improve our society using economics
shubham
so good night
hon
Why do people buy more grapes in December than in July?
lungi
because at time know money
Adu
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
why and for what was five kingdom of classification of organisms introduced
SUBHIKSHA Reply
give the ans as fast as possible
SUBHIKSHA
Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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