Download Musculoskeletal and digestive system practice ans

Musculoskeletal and digestive
system practice test answers
Question one
(a) Describe the function of cartilage
(Achieve Q)
The cartilage pads the ends of the
bones and provides protection by
shock absorption and provides a
smooth surface to reduce friction.
(b) Explain why skeletal muscles are
under voluntary control (Merit Q)
Those muscles on the Appendicular
skeleton are primarily responsible for
locomotion/movement.
They are generally stronger and
require more energy and therefore
need to be used only when required.
(c) Discuss how muscles, bones, joints,
tendons, and ligaments would work
together to bend and move the know
joint. (Excellence Q)
Describe
: define tendon and ligament
: contraction of hamstring cause leg to
move backwards
: Antagonistic pair (quadriceps and
hamstring)
Explain
: function of antagonistic pair
: function of tendon and ligaments
Discuss
: How movement is generated –
shortening of muscle etc (or a good
example)
Model answer:
The quadriceps and hamstring act as an
antagonist pair (i.e. when the quad
contracts and the hamstring relaxes the limb
straightens). When the hamstring contracts
and the quad relaxes, the lower leg will
move backwards.
The ligament link bones, whereas the
tendons link the muscle to bone across the
joint (the quad is thus connected to the tibia).
Contraction of the muscle thus generate
movement in the next part of the limb.
Question two
(a) Describe one function of bones other
than movement or support. Give an
example. (achieve Q)
- Storage of minerals (calcium and
phosphate)
- Protection of organs (e.g. brain, ribs)
- Production of blood cells in long bones
- Hearing (bones in middle ear)
- Breathing – movement of ribs
(b) Name the fracture most common in
children and explain why. (Merit Q)
Greenstick fracture
Young bones haven’t mineralized
(hardened) fully and therefore are
more flexible/bendy than adult bones.
Young bones tend to only break on one
side or break unevenly. Adults
generally snap the bone all the way
through (more brittle)
(c) Discuss how arthritis can affect the
mobility of a joint (Excellence Q)
Achieve: define arthritis
Merit: result (symptoms)
- Osteoarthritis caused by wear and tear
of cartilage. Results in swelling which
cause pain and immobility
- Rheumatoid arthritis caused by
overproduction of synovial fluid.
Results in stiffness which cause pain
and immobility
Excellence: give an account of how
movement is affected
For the joint to function correctly, the
cartilage should prevent rubbing and
the synovial fluid act as a lubricant
and shock absorber.
Once the joint has too much fluid, the
pressure and swelling prevents the
joint from bending as it should and
causes pain.
Question three
(a) Describe the purpose of the human
digestive system (Achieve Q)
- Breakdown complex organic molecules to
usable smaller/simpler forms
- Gain nutrition from other organisms as we
are heterotrophs/consumers
- As omnivores we need to be able to
process both plant and animal matter to
extract nutrients
(b) Explain why chemical digestion does not
begin in the mouth for all foods. (merit Q)
Achieve: The main enzyme in saliva is
amylase, which breaks starch down into
glucose. Different foods are broken down
in different regions of the gut by different
enzymes.
Merit: Any example
E.g. foods containing fats must wait until
they get to the ileum to be digested
(contain pancreatic juice which emulsifies
fat)
(c) Discuss how digestion of food can be affected
by changes in pH levels in the small intestine
(excellence Q)
Achieve: enzyme function at specific pH ranges
The pH changes by increasing – from acid in the
stomach to alkaline in the small intestine.
Merit: explain how different enzymes catalyses
different reactions, or about optimum pH
Excellence: relate to an example.
For example, bile is secreted in the small
intestines neutralizes acids from the stomach
and enables more enzymes to work
Question four
(a) Draw a simple labeled diagram of a tooth
see page 44 blue book (achieve Q)
Need 3 correct labels for achieve
(b) Explain why an adult human has more than
one type of tooth. (merit Q)
Achieve: The different types of teeth have
different jobs: incisors to cut, canines to
tear, premolars and molars to grind)
Merit: Humans are omnivores and therefore
have a combination of teeth for their diet.
Our teeth are not highly specialized due to
our use of utensils
Question five
(a) Describe the symptoms of bowel cancer
(achieve Q)
Any two of: weight loss, change in bowel
activity, faeces contain blood/mucus, lack
of energy/tiredness/paleness
(b) Explain why diarrhea can sometimes
lead to death (merit Q)
Achieve: Diarrhea is due to too much fibre
in the diet or due to pathogens (harmful
microbes)
Merit: Lack of fibre lead to watery faeces.
Persistent diarrhea can lead to
dehydration and lower GI tract infections.
Food moves too quickly through the gut 
little nutrients absorbed and too much
water is lost (possible bleeding of the
colon wall)
(c) Discuss how normal stomach functions is
affected by ulcers. (excellence Q)
Achieve: excess acid causing the stomach to
digest itself (hole in the mucous layer)
Merit: results in pain, bleeding, lowered food
intake, decreased ability to digest protein
Excellence: effects or good example mentioned
E.g. stomach usually breakdown proteins, when
an ulcer is present, the stomach has a lowered
ability to digest proteins. Bleeding (and pain) in
the stomach due to ulcers can result in nausea
and also lowered food intake.