Biology - Staying Alive
What is the process of aerobic respiration?
The release of energy from food, using oxygen
What is the word equation for aerobic respiration?
glucose + oxygen ----> carbon dioxide + water
What is energy used for?
Movement
Warmth
Growth & Repair
What two chemicals can detect carbon dioxide?
Limewater
Hydrogen Carbonate Indicator
What colour change occurs in limewater?
Clear to Milky/Cloudy
What colour change occurs in Hydrogen Bicarbonate Indicator?
Red/Orange to Yellow
What is the function of the nose?
To warm, filter and moisten the air when it passes through
What is the function of the larynx?
The vocal chords inside make sound when air passes over them
What does the windpipe have around it and what is their function?
Rings of cartilage which keep it open
What does the windpipe divide into?
Two bronchi
What are the hairs around the cells of the windpipe called?
Cilia
What do some cells in the windpipe produce?
Mucus
What happens in the windpipe lining?
Dust and bacteria gets trapped in the mucus. The cilia pushes it to the throat to be swallowed
What does each bronchus branch off into?
Bronchioles
What is at the end of each bronchiole?
Alveoli
What happens in the alveoli?
Gas exchange
How many alveoli are there in each lung?
Millions
What happens when breathing in?
The intercostal muscles contranct and pull the ribs up and out
The diaphragm contracts and moves down
Chest volume increases
Air pressure in chest decreases
Air rushes into lungs
What happens when you breathe out?
Intercostal muscles relax causing ribcage to fall down and in
Diaphragm muscle relaxes and moves up
Volume in chest decreases
Air pressure in chest increases
Air rushes out of lungs
How does gas exchange work?
Deoxygenated blood arrives at lungs
Oxygen diffuses from air in alveolus into blood
CO2 diffuses in opposite direction
Oxygenated blood leaves lungs
Why is gas exchange at alveoli very efficient?
Large surface area
Good blood supply
Walls of alveoli and capillaries very thin
Walls of alveoli are moist
What does double circulation mean?
For every complete circuit of body, blood passes through heart twice
What is the journey of a blood cell through the heart?
vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulnonary vein -> left atrium -> left ventricle -> aorta
Why is the wall of left ventricle thicker than wall of right ventricle?
Left ventrical pushes blood all around body. Right ventricle only pushes blood to lungs
What is the function of valves?
To prevent backflow of blood
Why does your heart not get tired when pumping blood?
The cardiac muscle which constantly contracts
How does the heart get its supply of food and oxygen?
Coronary arteries
What is the function of arteries?
Carry pulses of high pressure blood away from heart
What is the wall structure of an artery?
Thick with lots of muscle and elastic tissue
What is the width of an artery's lumen?
Narrower than a vein
Explain the reason for an artery's structure.
It means that an artery won't burst under high pressure
What is the function of veins?
To return low pressure blood back into heart
What is the structure of a vein?
Thinner than an artery with less muscle and elastic tissue
What is the width of a vein's lumen?
Wider than an artery
Explain the reason for a vein's structure.
It lets low pressure blood pass easily through
What hsppens when blood flows the right direction through a vein?
The valve flaps are pushed against the wall
What happens when blood tries to flow the wrong way through a vein?
The valve flaps close, preventing blood flow
What do arteries split into in an organ?
Capillaries
How thin are capillary walls?
One cell
How narrow is a capillary's lumen?
Blood cells have to travel in single file
How does the narrow wall of a capillary help?
It makes it easy for materials to pass in and out of the blood
How does the narrow lumen of a capillary help?
It slows down blood flow, giving more time for exchange to occur
What is plasma?
The fluid part of blood
What does plasma do?
Transports materials around the body
What is the shape of a red blood cell?
A biconcave disc
What do red blood cells do?
Carry oxygen around the body
What are the two types of white blood cells?
Phagocyte
Lymphocyte
What do white blood cells do?
Protect us against disease
What do phagocytes do specifically?
The eat the bacteria and viruses
What do lymphocytes specifically do?
They produce antibodies to kill the bacteria and viruses
What are platelets?
Tiny fragments of cells
What do platelets do?
Help the blood clot
What are two advantages to blood clotting?
Not losing as much blood
Bacteria and viruses dont enter body
What happens in a normal artery?
Blood flows through easily
Lining is smooth and lumen is open
What happens in a diseased artery?
Cholesterol sinks into cracks
It forms a bulging plaque
Plaque partly blocks lumen of artery
What are some risk factors for heart disease?
Smoking
Fatty diet
Stress
Lack of exercise
Being very overweight