organisation Flashcards
What do the human lungs provide an
exchange surface adapted for?
absorbing oxygen – needed for respiration – into the blood from the air transferring
carbon dioxide – produced by respiration – from the blood into the lungs then the air
What is the structure of the respiratory system?
The human respiratory system
is adapted to allow air to pass in and out of the body, and for efficient gas exchange to happen. The lungs are enclosed in the thorax, surrounded and protected by 12 pairs of ribs. The ribs are moved by two sets of
intercostal muscles. There is a muscular
diaphragm below the lungs. The lungs are sealed within two airtight pleural membranes. These wrap around the lungs and line the rib cage. The trachea, or windpipe, branches into two bronchi – one bronchus to each lung. Rings of cartilage in the walls of the trachea help to keep it open as air is drawn in. The bronchi split into smaller branches and then into smaller tubes called bronchioles. Each bronchiole ends in a cluster of microscopic air sacs called alveoli.
How is the human respiratory system adapted?
To allow air to pass in and out of the body, and for efficient gas exchange.
The lungs are enclosed in the (a) surrounded and protected by (b) pairs of ribs.
(a) thorax
(b) 12
What muscles move the ribs?
2 sets of intercostal muscles.
The lungs are sealed within two airtight (a) (b)
(a) pleural
(b) membranes
What do the trachea/ windpipe branch into?
2 bronchi, branching into each lung.
What help to keep the walls of the trachea open as air is drawn in?
Rings of cartilage
bronchi split into smaller branches and then into smaller tubes. what are these called?
bronchioles.
Each bronchiole ends in a cluster of (a) air sacs called (b)
(a)microscopic
(b) alveoli
What is gaseous exchange?
The exchange of gases occurs between the alveoli and blood in the capillaries
that supply the lungs. Capillaries cover 70% of the outside of alveoli, providing a large surface area for gases to diffuse across.
How are the alveoli are adapted to provide a very large surface area for gaseous exchange?
small size - each alveolus is a small sphere about 300 μm in diameter, giving it a larger surface area to volume ratio than larger structures
number - there are around 700 million alveoli – ie 350 million per lung
What is the role of enzymes in metabolism?
Large nutrient molecules are broken down into smaller ones by enzymes in the digestive system, this enables the molecules to be absorbed into the blood across the wall of the small intestine.
What happens if an enzyme is in extreme conditions?
It denatures, stops working, loses shape.
Enzymes bind (a) at key locations in their structure called (b)
(a) substrates
(b) active site
Amylase (made in the (a) breaks down (b) Lipase (made in the (c) ; breaks down (d)) Protease (made in the (e); breaks down (f))
(a) mouth and pancreas
(b) complex carbohydrates
(c) pancreas
(d) fats
(e) pancreas
(f) proteins
What is bile?
made in the liver, stored in the gall bladder and released into the small intestine. It neutralises the acid from the stomach to create a pH suitable for the enzymes of the small intestine and emulsifies fats so they can be more easily digested by lipase enzymes. ph of 8.2
Does temperature increase the rate of fat breakdown by lipase?
Yes, temperature increases the rate of reaction
