Gas Exchange in Humans

Created by

Gerald Kamau

Cards (73)

What is the thorax? 
The upper half of the torso encased by the diaphragm and ribs
What is the trachea?
The breathing tube from the throat to the bronchus which is strengthened by rings of cartilage to prevent collapse under negative pressures when inhaling.
What is the bronchus?
A branch of the trachea that carries air into one lung
What are bronchioles? 
Small tubes that carry air into the alveoli
What are alveoli? 
Tiny air-sacs in the lungs where gas exchange occurs
What is the diaphragm?
A big sheet of muscle separating the thorax from the abdomen
What are ribs? 
Bones that help to support the thorax
What are the intercostal muscles?
The muscles that contract to move the ribs
What are pleural membranes? 
Thin, moist membranes forming an airtight seal between the lungs and the ribs/diaphragm
Describe the process of breathing in
The diaphragm contracts and flattens, increasing the size of the thorax.
The external intercostal muscles between the ribs contract, pulling ribs up and out. The lungs increase in size, so the pressure inside them falls. This causes air to rush in through the nose and mouth via diffusion.
Describe the process of breathing out.
The diaphragm relaxes and returns to its relaxed dome shape, reducing the size of the chest. The external intercostal muscles relax, so that the ribs move in and down. The lungs decrease in size, so the pressure inside increases and air is pushed up through the trachea and out through the mouth or nose, via diffusion.
How are alveoli adapted for gas exchange via diffusion?
Large surface area, thin walls and moist lining
How is our airway kept clean?
They are lined with cells with fine hair like extensions called cilia, which beat and move the mucus (containing bacteria and other tiny particles) to the back of the throat where it is swallowed.
How does cigarette smoke effect cilia?
It irritates the lining of the airway, stimulating more mucus to be produced. The cilia are damaged by chemicals in the smoke and stop moving. The mucus is not moved and accumulates. The smoker coughs to try and get rid of it. Bacteria in the mucus can cause bronchitis.
How does tar effect a smokers health?
Tar accumulates in smokers lung tissue. It contains chemicals called carcinogens which cause mutations leading to uncontrolled cell division and cancer.
What is emphysema? 
When the alveoli are damaged
How does emphysema effect a smoker?
Over time, the inner walls of the alveoli weaken and rupture, creating larger air spaces instead of many small ones, reducing SA. Oxygen has to travel further to diffuse to meet an exchange surface, reducing the oxygen levels in a persons blood. Patients may need to breathe oxygen enriched air through a mask.
Why is carbon monoxide dangerous?
Carbon monoxide binds to the haemoglobin in place of oxygen.
The binding is permanent and so reduces the amount of oxygen carried by red blood cells.
Why does smoking increase a persons risk of a heart attack?
Coronary arteries transport blood to the heart muscle cells which need a constant supply of glucose and oxygen for respiration for contractions. If a clot forms, an area of heart muscle dies as it does not get oxygen and glucose, causing a heart attack.
How does smoking cause coronary heart disease?
Chemicals in the smoke cause cholesterol to be released into the blood. Cholesterol can attach to the lining of blood vessels and cause thickenings and clots, called atheroma.
What is nicotine and what are its effects?
It is a highly addictive drug, which is also a stimulant and a relaxant, changing peoples moods. It speeds up HR which increases BP. It is very difficult to give up.
What are some of the symptoms a smoker might experience?
Insensitivity to smell, coughing, wrinkles, bad breath, yellow teeth, dulled taste buds, gum disease, back pain, reduced fertility in women, urinary incontinence, slower wound healing
Why do multicellular organisms need transport?
To carry oxygen from the lungs to the cells, to carry food from the gut to the cells, to carry carbon dioxide from the cells to the lungs, to carry waste products from the liver to the kidneys.
What is the heart?
A muscular organ that pumps blood all the way round the body and back again.
Which side of the heart pumps deoxygenated blood?
The right side
Which side of the heart pumps oxygenated blood?
The left side
Which blood vessels take blood away from the heart?
Arteries
Which blood vessels take blood back towards the heart?
Veins
Which blood vessels have valves?
Veins
Why do veins have valves?
To prevent blood flowing in the wrong direction
Describe the structure of the atria and their purpose.
Atria have thin walls, they receive blood and have to pump it into the ventricles
Describe the structure and purpose of the left ventricle.
The left ventricle have thick muscular walls, as it must be able to generate enough pressure to pump the blood up and out of the heart
Describe the structure and purpose of the right ventricle.
The wall of the right ventricle is thinner because it only has to pump blood to the lungs
What is heart rate?
A measure of how frequently the heart beats
What is resting heart rate?
The rate at which a heart beats when a person is a rest
What is the average resting heart rate for an adult?
60-80 bpm
What factors effect a persons resting heart rate?
Age, fitness, health/illness
What happens to heart rate during exercise and why?
It increases to supply enough blood and glucose to the working muscles, and remove waste products
Which hormone increases heart rate?
Adrenaline
Where is adrenaline produced?
In the adrenal glands located above the kidneys