B3 Extra Flashcards
What is the hierachy of tissues in the body
Cells–>tissues—>organs—>organ systems—>organisms
What happens if PH is too high or too low
If PH is too high or too low it interferes with the bonds holding the enzyme together . This changes the shape of the active site of the enzyme and causes it to become denatured
What is usually the best PH for an enzyme to work at
Enzymes usually work best at Ph 7
What PH does the pepsin enzyme work best at
Pepsin (which breaks down protiens in the stomach) works best at PH 2 which means its suited to the acidic conditions of the stomach
Where is bile produced,stored and released into
Bile is produced by the liver, it is stored in the gall bladder and released into the small intestine
What does bile do in the small intestine.
The hydrochloric acid from the stomach makes conditions too acidic for enzymes in the small intestine to work . Bile neutralises the stomach acid in the small intestine and makes the PH perfect for the enzymes to work in
What does the salivary gland do
The salivary gland produces the enzyme amylase
What is the function of the rectum
The rectum is where the feaces are stored before they leave through the anus
What happens in the large intestine
In the large intestine excess water is absorbed from food
What is the function of the gall bladder
The gall bladder is where the bile is stored before it is released into the small intestine
What is the function of the liver
The liver is where bile is produced . Bile neutralises stomach acids and emulsifies fats
What does the pancreas do
The pancreas produces protease,amylase and lipase . It releases these into the small intestine
What does the stomach do
- The stomach pummels the food with its muscular walls
- Stomach produces the protease enzyme ,pepsin
- It produces hydrochloric acid : to kill bacteria,to give the right Ph for protease to work (PH 2)
What does the small intestine do
The small intestine produces protease,amylase and lipase
-It is where digested food is absorbed out of the digestive system into the blood
What is the thorax
The thorax is the top part of the body
Whta are the lungs protected by
The lungs are protected by the ribcage
What surrounds the lungs
Pleural membranes surround the lungs
Where does the air we breathe in go to
The air we breathe in goes to the trachea
What does the trachea split into
The trachea splits into two tubes called the bronchi, one goes to each lung
What do the bronchi split into
The bronchi split into smaller tubes called bronchioles which eventually end at alveoli
What happens in the alveoli
Gas exchange takes place in the alveoli
-Each alveoli is surrounded by a network of blood cappilaries
How does gas exchange take place in the alveoli
The blood in the blood capillaries passing next to the alveoli have just returned to the lungs from the rest of the body so contain lots of carbon dioxide and very little oxygen. Oxygen diffuses out from the alveoli ( where there is a high concentration ) to the blood (low conc) and carbon dioxide diffuses out of the blood into the alveoli to be breathed out
What happens when the red blood cells carrying oxygen reach the body cells
When red blood cells reach body cells oxygen diffuses from the red blood cells (high conc)into the body cells(low conc) . Carbon dioxide simultaneously diffuses from body cells into red blood cells ready to be carried back to the lungs
What do cappilaries do
Cappilaries carry blood very close to every cell in the body so substances can be exchanged
-They supply food and oxygen and take away waste e.g co2 from blood cells
What adaptations do cappilaries have to allow efficient substance exchange
- Cappilaries have permeable walls so substances can diffuse in and out
- Cappliaries have walls one cell thick . This increases the rate of diffusion by decreasing the diffusion pathway distance
How are exchange surfaces adapted in multi cellular organisms to maximise effectiveness
- Exchange surfaces have a thin membrane so there is only a short distance to diffuse
- Exchange surfaces ahge a large surface area for a higher rate of diffusions
- Exchange surfaces in animals have lots of blood vessels to get stuff in and out of the blood quickly
- Gas exhange surfacss in animals are often ventilated too - air moves in and out
How can active transport be used in the gut
Active transport can be used in the gut so that nutrients can be taken from the gut too the blood even if there is a smaller concentration of nutrients in the blood
