1. Flexion of the arm occurs when the biceps contracts and the triceps relaxes.

2. The radius is on the thumb side of the lower arm.

3. Antagonistic pairs of muscles produce opposing movement.

4. Functions of the skeleton are to:

• form a framework to support the body;
• serve as a reserve of phosphate and calcium ions;
• produce red blood cells.

5. In primates, the thumb and index finger are opposable, thus enabling the power grip.
In humans, the thumb is longer than in other primates and the index finger is shorter than in other primates.
These factors also enable humans to have the precision grip as used, for example, to peel a banana.

6. Adaptations for bipedal locomotion include having:

• an enlarged calcaneum (heel bone);
• a short broad pelvis;
• wedge-shaped lumbar vertebrae;
• the foramen magnum is at the base of the skull.

7. The contraction of the diaphragm and the intercostal muscles during inspiration cause the pressure in the lungs to decrease.

8. Carbon dioxide (CO₂) leaves the blood stream at the alveoli.

9. The foot is tilted up by the contraction of the anterior tibialis (shin muscle) and relaxation of the gastrocnemius (calf muscle).

10. Muscle tone refers to the constant state of partial muscle contraction.

11. There is a ball and socket joint between the femur and the pelvis.
(There is a ball and socket joint between the head of the femur and the acetabulum.)

12. Know that:

• The gall bladder stores bile which will later emulsify fats.
• The small intestine absorbs small molecules from digested food.
• The liver receives nutrients from the small intestine via the blood.
• The large intestine removes water from the remains of undigestable food.

13. Know that:

• The pancreas releases digestive enzymes (trypsinogen and pancreatic amylase).
• The stomach carries out both mechanical and chemical digestion.
• The stomach releases a digestive enzyme (pepsinogen) and hydrochloric acid (HCl).
• The small intestine breaks down food and absorbs these products of digestion.
• The (cardiac and pyloric) sphincters regulate the passage of food.

14. Observation: the ring-tailed lemur (Lemur catta) has a pronounced snout.
Inference: it relies heavily on its sense of smell compared to other primates.

15. The chimpanzee is a primate, an anthropoid, and a pongid.

16. Pentadactyl means with five digits.

17. Ischial callosities are a unique feature of Old World monkeys.

18. The graph (not available here) shows that:

• The consumption of suger per person in Canada is similar to that of the USA.
• There is some realtionship between sugar consumption and death rate.
• The death rate by coronary heart disease in Japan is approximately one-eighth that of Canada.

19. Primates have nails rather than claws.

20. Diffusion of oxygen is from alveoli to the blood capillaries. Diffusion of carbon dioxide is from the blood capillaries to the alveoli.

21. During breathing, the sternum rises and falls with the thoracic (rib) cage.

22. During inspiration, while the other intercostal muscles relax, the intercostal muscles contract causing the thoracic cage to move upwards and outwards.

23. Inspiration is breathing in.

24. Digestion is best described as the breakdown of large organic molecules into smaller, absorbable molecules.

25. A person’s whole body would not be put inside an iron lung because there would be no difference in the air pressure inside or outside the body,
so the iron lung would not breathe for the patient.

26. Asthma is caused by constriction of smooth muscle in the walls of the bronchioles.

27. Enzymes work best at specific environmental conditions of pH and temperature, e.g. most human enzymes work best at 37°C.

28. If the amount of chemical energy (food) taken in by a person exceeds their needs,
the extra energy is mostly stored in organic compounds of large molecular size,
that is, if energy intake exceeds energy expenditure, then the excess energy is stored as fat.

29. The independent variable is the one controlled and altered by the experimenter. As an example, it could be that milk is (or isn’t) added to the diet.

30. Any conclusion must be supported by all of the results.

Revision

1. A tendon is a tough band of connective tissue that attaches a muscle to a bone.

2. A power grip is a grip whereby the object is grasped between the undersides of the fingers and the palm of the hand, e.g. holding a hammer.

3. A precision grip is a grip whereby the object is gripped between the thumb and finger, e.g. holding a pencil or a needle.

4. An osteocyte is a bone cell.

5. The Haversian system is an interconnecting system of canals in compact bone providing an extensive blood and lymphatic supply throughout the bone.

6. The matrix is the nonliving material in the interstices between the osteocytes.

7. A ligament is a tough band of connective tissue linking bone to bone.

8. A synovial joint is a freely moveable joint with a synovial capsule, synovial membrane and synovial fluid.

9. A complicated fracture is a broken bone which damages another important structure.

10. Antagonistic muscles are pairs of muscles which work together to permit a certain movement. As one muscle of the pair contracts, the other relaxes.

11. The foramen magnum is the opening at the base of the skull through which the spinal cord passes.

12. Red bone marrow is found in the medullary canal (marrow cavity) of bones and is the principal site for the formation of red blood cells.
In particular, found in the cavities of the pelvis, vertebrae and ribs of adults. [90]

13. Compact bone is dense, strong bone tissue found on the surfaces of bones. It is very thick in the diaphysis (shaft) of long bones.

14. Cancellous bone is porous bone containing many blood vessels. It is found in the epiphyses (ends) of long bones.

15. The medullary canal is the canal in the centre of long bones containing the bone marrow.

16. Yellow bone marrow is found in the medullary canal of long bones and is primarily composed of fat and is not capable of blood cell formation.

Revision Questions

1. Sutures (fixed joints, immovable joints) are the joins between the bones of the skull.

2. A bursa serves as a cushion.

3. There are seven vertebrae in the cervix (the cervical region) of the spine.

4. Freely moveable joints (synovial joints) are lubricated by synovial fluid.

5. The axial skeleton consists of the skull, the vertebral column and the rib cage.

6. Osteoporosis results in the gradual reduction in bone formation and is common in older women. It may be caused by dietary factors
(e.g. a lack of calcium ions and a lack of vitamin D), lifestyle factors (e.g. smoking and a lack of physical activity) and hormonal factors
(e.g. a loss of sex hormones in women as they get older).

7. The femur, fibula, tibia and patella are all part of the appendicular skeleton.

8. The wriggly lines on the cranium are immovable joints called sutures.

9. Bursae act as cushions in some joints such as the knee joint.

10. If a person broke his spinal cord at the lower part of the cervical area of the spinal column, he would be paralysed from the neck down.

11. The pair of similar strength bones in the lower arm are the radius and ulna.

12. First aid for a person with a broken arm would be to treat for shock and then put a splint on the broken limb.

13. When running, to extend the front leg, the runner must contract the quadriceps and relax the hamstrings.

14. Humans have an opposable thumb which enables them to touch the ends of every finger with it. This allows the precision grip to be used.

15. Hyaline cartilage covers the articular surfaces of the epiphyses of long bones.

16. In an experiment, the independent variable is the one altered by you, the experimenter.

Revision Questions

1. Bending of the arm towards the elbow is due to contraction of the biceps muscle while the triceps muscle is relaxed.

2. The fingers are the phalanges; the radius is on the thumb side of the lower arm, and the point of the elbow is the end of the ulna.

3. There is a synovial joint (freely moveable) at both ends of the humerus.

4. The elbow and knee are hinge joints; there is a pivot joint between the atlas and axis at the top of the spinal column.

5. The Haversian canal at the centre of the Haversian system contains blood vessels.
The bony matrix contains a large amount of inorganic material such as calcium ions.
Spongy bone does not have Haversian systems.

6. Osteoporosis results in the gradual reduction in bone formation and is common in older women. It may be caused by dietary factors
(e.g. a lack of calcium ions and a lack of vitamin D), lifestyle factors (e.g. smoking and a lack of physical activity) and hormonal factors
(e.g. a loss of sex hormones in women as they get older).

7. The femur, fibula, tibia and patella are all part of the appendicular skeleton.

8. The wriggly lines on the cranium are immovable joints called sutures.

9. Bursae act as cushions in some joints such as the knee joint.

10. If a person broke his spinal cord at the lower part of the cervical area of the spinal column, he would be paralysed from the neck down.

11. The pair of similar strength bones in the lower arm are the radius and ulna.

12. First aid for a person with a broken arm would be to treat for shock and then put a splint on the broken limb.

13. When running, to extend the front leg, the runner must contract the quadriceps and relax the hamstrings.

14. Humans have an opposable thumb which enables them to touch the ends of every finger with it. This allows the precision grip to be used.

15. Hyaline cartilage covers the articular surfaces of the epiphyses of long bones.

16. In an experiment, the independent variable is the one altered by you, the experimenter.

Revision Questions