Gas Exchange, Circulatory System, Drugs, Alcohol, and Smoking

Comprehensive practice flashcards covering respiratory gas exchange, anatomy of the lungs, mechanics of breathing, circulatory structures, blood components, drug classifications, and the health effects of alcohol and tobacco smoke.

What structure protects the lungs from physical damage?

The rib cage protects the delicate lungs so they do not get damaged.

What is the primary function of the lungs in the body?

To carry out gas exchange by supplying oxygen to the cells and taking carbon dioxide from the cells into the lungs to be exhaled.

What is the key difference between breathing and respiration?

Breathing is the movement of $\text{O}_2$ and $\text{CO}_2$ into and out of the lungs (taking in), whereas respiration is the chemical use of oxygen to release energy inside cells (releasing energy).

What anatomical pathway does air follow from the throat down to the gas exchange surfaces in the lungs?

Air travels down the trachea, which splits into two branches called the bronchus, which then branch further into bronchioles, ending at tiny air sacs called alveoli.

Why is the left human lung typically smaller in size than the right lung?

The left lung is smaller to leave anatomical space for the heart to fit in.

How does gas exchange occur between the alveoli and capillaries?

Carbon dioxide diffuses out of the red blood cells across into the alveoli to be exhaled, while oxygen diffuses out of the alveoli into the red blood cells to be carried around the body.

What are four key adaptations of the alveoli that facilitate efficient gas exchange?

Thin walls (providing a short diffusion pathway), large surface areas, moist surfaces, and a good blood supply.

Why is the volume of nitrogen gas inhaled identical to the volume exhaled, even during strenuous exercise?

The human body does not use or require nitrogen, so none is absorbed or produced.

Why does a person exhale more carbon dioxide and less oxygen during physical exercise?

More cellular respiration takes place during exercise, which consumes more oxygen and produces more carbon dioxide as a waste product.

What two body responses occur to deliver more oxygen around the body during exercise?

Breathing rate increases (taking deeper and more frequent breaths) and heart rate increases (to pump blood faster around the body).

What physiological changes take place in the chest cavity during inhalation (breathing in)?

The intercostal muscles contract (pulling the ribcage up and out), the diaphragm contracts (moves down), the volume inside the chest increases, and the pressure decreases, drawing air into the lungs.

What physiological changes take place in the chest cavity during exhalation (breathing out)?

The intercostal muscles relax (pulling the ribcage down and in), the diaphragm relaxes (moves up), chest volume decreases, and chest pressure increases, forcing air out of the lungs.

In this bell jar model of the respiratory system, what do the jar, the balloons, and the bottom rubber sheet represent?

The bell jar represents the chest cavity, the balloons represent the lungs, and the rubber diaphragm/sheet represents the diaphragm muscle.

What are the three main components that make up the human circulatory system?

The heart, blood vessels, and blood.

What is the function of blood plasma, and what is its primary adaptation?

Plasma is the liquid part of the blood that carries other blood components; it is adapted by being a liquid so it can readily flow around the body.

How are red blood cells structurally adapted to perform their function of transporting oxygen?

They have a biconcave disc shape, which gives them a larger surface area for gas diffusion.

What is the function of white blood cells?

They fight off infections and contain specialized enzymes.

What role do platelets play in the blood?

They clot easily to form scabs when the skin is cut, stopping bleeding and preventing infection.

What are three structural and functional features of arteries?

They have thick walls, a narrow lumen, carry blood under high pressure away from the heart, and hold bright-red oxygenated blood (except for the pulmonary artery).

Why do veins contain valves, and how do their walls compare to arteries?

Veins have thinner walls, a wider lumen, and contain valves to prevent the backflow of blood because blood moves at lower pressure.

What are capillaries, and how are their walls adapted for substance exchange?

They form a vast network linking arteries and veins where substances diffuse into cells; their walls are only a single cell thick to minimize the diffusion pathway.

Why does the left side of the heart possess significantly thicker muscle than the right side?

The left side has to pump blood at high pressure around the entire body, whereas the right side only pumps deoxygenated blood to the lungs.

What is the scientific definition of a drug?

Chemical substances that affect the way the body works by altering the chemical reactions taking place inside it.

What differentiates medicinal drugs from recreational drugs?

Medicinal drugs are taken to help people recover from illness or relieve pain (e.g., paracetamol, ibuprofen), while recreational drugs are taken voluntarily for pleasure (e.g., caffeine, nicotine, alcohol, cocaine).

Why does substance abuse frequently result in severe damage to the liver?

The liver is the organ responsible for breaking down and detoxifying drugs and chemicals in the bloodstream.

What are the four main categories of drugs based on their bodily effects?

Depressants (reduce brain activity), Stimulants (increase brain activity), Hallucinogens (cause users to see or hear things that are not real), and Painkillers (reduce pain).

Under UK law, what substances fall under Class A drugs, and what are the penalties for dealing them?

Ecstasy, LSD, heroin, cocaine, crack, magic mushrooms, and amphetamines (if prepared for injection); dealing them carries up to life in prison, an unlimited fine, or both.

What are the legal possession penalties for Class B drugs (e.g., cannabis, amphetamines, Ritalin)?

Up to $5\text{ years}$ in prison, an unlimited fine, or both.

What is drug addiction, and what symptoms commonly accompany withdrawal?

Addiction is dependence where the body requires the drug to feel normal; withdrawal symptoms include headaches, anxiety, and sweating.

What active drug is found in alcoholic drinks, and how does it act on the brain?

Ethanol; it acts as a depressant that is absorbed into the bloodstream, travels to the brain, and slows down bodily reactions.

How much pure alcohol constitutes $1\text{ unit}$ under UK medical guidelines?

$1\text{ unit} = 10\,\text{cm}^3$ of pure alcohol.

What is the maximum recommended alcohol limit per week for men and women?

Neither men nor women should regularly exceed $14\text{ units}$ per week.

What is liver cirrhosis?

Irreversible scarring of the liver caused by long-term heavy alcohol use, which eventually leads to liver failure.

What condition is illustrated by these distinct facial characteristics (including micrognathia, indistinct philtrum, and short palpebral fissures)?

Fetal Alcohol Syndrome (FAS), caused by alcohol crossing the placenta and damaging the developing fetal brain and organs.

What is the recommended safe intake level of alcohol during pregnancy?

There is no known safe amount; doctors advise consuming no alcohol during pregnancy to avoid birth defects, low birth weight, miscarriage, or stillbirth.

Which toxic chemical additives shown in this diagram are inhaled through cigarette smoke?

Substances such as tar, nicotine, carbon monoxide, methane, methanol, butane, acetone, ammonia, cadmium, radon, toluene, hexamine, and hydrogen cyanide.

How does cigarette tar damage the ciliated epithelium in the respiratory tract?

Tar flattens the cilia hairs, preventing them from sweeping mucus and trapped bacteria out of the lungs, significantly increasing the risk of infection.

Why is nicotine both addictive and hazardous to the cardiovascular system?

It triggers dopamine release in the brain causing addiction, while acting as a stimulant that accelerates heart rate and constricts (narrows) blood vessels.

Why is carbon monoxide inhalation particularly harmful to red blood cell function?

Carbon monoxide binds to haemoglobin preferentially over oxygen, drastically reducing the blood's capacity to transport oxygen to body tissues.

What respiratory condition causes the alveolar damage and reduced lung surface area shown in this diagram?

Emphysema, which destroys the alveoli walls, severely reducing the surface area for gas exchange and causing extreme shortness of breath.

What is chronic bronchitis, and how is it caused by smoking?

It is an inflammation of the bronchioles and bronchial lining where cilia are damaged and thick mucus accumulates due to irritation from smoke.

What are carcinogens, and how many are known to exist in tobacco smoke?

Carcinogens are chemicals that damage cellular DNA and mutate genes, causing uncontrolled cell growth and cancer; tobacco smoke contains at least $80$ of them.