Human Tissues, Organs and Organ Systems Flashcards
Order these from smallest
to largest: organ, cell,
organism, tissue, organ
system
Cell, tissue, organ, organ
system, organism
What is tissue?
A group of specialised cells with
similar structure performing the
same function
What is an organ?
An aggregation of tissues that
perform a specific function; e.g.
the stomach is an organ made of
muscular tissue to churn the
contents, epithelial tissue to
cover the inside and outside of
the stomach and glandular tissue
to produce digestive enzymes
What is an organ
system?
A collection of organs that
perform a specific function
Name the components of
the digestive system
Salivary glands, oesophagus,
stomach, pancreas, liver, small
intestines, large intestines
What is the function of
saliva?
Lubricate food so it is easier to
swallow.
Contains amylase to start
digesting carbohydrates.
What is the oesophagus?
A 20cm long tube that connects
the mouth to the stomach.
What is the anus?
Opening at the end of the digestive system.
What is the function of
the stomach?
Releases protease. Ensures pH at 2-3 so
protease works at optimum.
What is the function of
the liver?
To produce bile which is then stored in
the gall bladder.
What is the function of
bile?
To emulsify fats – break up large fat
drops into small fat droplets. Bile is
alkaline so it also neutralises stomach
acid
What is the function of
the small intestines?
To absorb soluble foods into the blood
stream; this is where digestion occurs
What is the function of
the pancreas?
Produces carbohydrase, protease,
lipase.
What is the function of
the large intestines?
Absorb water and salts from the
undigested food producing faeces
What are villi?
Finger-like1cell-thick projections of the
lining of the small intestines to increase
the surface area for an increased rate of
diffusion/absorption of nutrients into the
blood stream. One cell thick to shorten
the diffusion distance. Good blood supply
to maintain diffusion gradient.
What is peristalsis?
Walls of the digestive system have rings
of muscles around them which contract
behind the bolus (ball of food) to push it along
What are carbohydrates
broken down into?
Glucose molecules
What are proteins broken
down into?
Polypeptides first which are
further broken down into amino
acids
What are lipids (fats) broken
down into?
Fatty acids and glycerol.
What is a substrate?
The molecule on which an enzyme acts.
What is the active site of an
enzyme?
The region of the enzyme that
binds to the substrate.
What is the lock and key
principle?
Enzymes are specific for each
substrate. The substrate fits
into the active site like a key
fits into a lock to help break
substrate bonds.
What happens to enzymes at
high temperatures/extreme
pH?
They denature. The shape of
the active site is permanently
distorted.
Why don’t enzymes work well
at very low temperatures?
Kinetic energy too low.
How do you test for starch?
Add iodine which will turn blue-
black if starch is present.
How do you test for glucose?
Add 10ml of Benedict’s
solution (blue) to 1ml of
sample. Warm. A red-brick
precipitate will form.
How do you test for proteins?
To 2ml of sample add 2ml of
Biuret solution. If a protein is
present the colour will change
to light lilac purple. If no
protein is present, the colour
will be cloudy blue.
How do you test for fats/lipids?
Half fill a test tube with water. Add 1 drop of sample. Shake the test tube. If a fat is present, an emulsion will form.
What is an artery?
A large blood vessel that carry
oxygenated blood away from
the heart.
