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.