Stage 2 Biology: Homeostasis Test

SACE ID:

1. Refer to the following diagram, which shows a cross-section of the spinal cord of a mammal: KA2

• J. One interneuron is not functioning.
• K. Neither motor neuron is functioning.
• L. No reflex response is occurring.
• M. One motor neuron is not functioning.

2. Which one of the following combinations correctly compares a feature of the nervous system with a feature of the endocrine system? KA2

• J.
• K.
• L.
• M.

3. The gills of a marine snail close when its skin is touched. Which one of the following combinations correctly identifies the receptor, the direction of transmission, and the effector in this reflex response? KA2

• J.
• K.
• L.
• M.

4. When faced with a sudden and unexpected threat, the human body will often react by releasing adrenaline into the blood. Adrenaline is a KA1

• J. neurotransmitter that increases the speed of nerve impulses.
• K. catalyst that increases the breakdown of glucose.
• L. hormone that increases blood pressure and breathing rate.
• M. protein that is a source of instant energy for muscle cells.

5. In 1877 the American biologist Joel Allen observed that the length of arms, legs, and other appendages of warm-blooded animals affected the rate at which they lost heat to the environment. Allen observed a consistent difference in the limb length of individuals in populations of the same species living in warm climates near the equator, in comparison with those living in cold climates further from the equator. Which one of the following statements is consistent with Allen's observation? IAE3

• J. In cold climates, animals need to conserve as much heat as possible and therefore have longer limbs.
• K. In warm climates, the larger the surface area of the limbs, the faster the animals lose heat to the environment.
• L. In warm climates, animals have longer limbs that increase their surface area and minimise heat loss.
• M. In cold climates, animals have shorter limbs and a larger surface area-to-volume ratio.

6. When a person eats a sugary meal, the pancreas detects an increase in blood glucose. The pancreas secretes the hormone insulin which causes muscle cells to take in glucose from the blood. Which one of the following statements is true? KA2

• J. This is an example of a feedback mechanism because the insulin is transported around the body in the blood.
• K. This is not an example of a feedback mechanism because in people with diabetes, blood sugar is not controlled.
• L. This is an example of negative feedback because the muscle cells will reduce the blood glucose level.
• M. This is not an example of negative feedback because the message is hormonal and does not rely on nervous transmission.

7. Scientists at Washington University have recently discovered that odour receptors are found not only in the nose, but also in the lungs. When odour receptors in the nose detect chemicals such as cigarette smoke, they send a nerve impulse to the brain and the smell of the cigarette smoke is then sensed. Odour receptors in the lungs are called pulmonary neuroendocrine cells (PNECs). When PNECs detect chemicals such as cigarette smoke, they release hormones that cause the airways to constrict. In some people constriction of the airways results in an asthma attack. It is thought that people with asthma may have hypersensitive PNECs. Which one of the following statements is not consistent with this information? IAE3

• J. The airways of people with asthma would be constricted before they sense the smell of cigarette smoke.
• K. Hormones released by PNECs would travel through the bloodstream.
• L. Drugs that block hormone receptors in the airways could be used to treat asthma.
• M. The constricted airways will not return to normal until the smell can no longer be sensed.

8. Refer to the flow diagram below which shows the regulation of Carbon dioxide concentration in the blood to answer the question that follows. KA2

• J. respiratory (intercostal) muscles
• K. respiratory centre in the brain
• L. Increase in the rate and depth of breathing
• M. motor nerve impulses

9. A person detects the smell of hot food in the air as he passes a restaurant. Shortly afterwards he notices that the amount of saliva in his mouth has increased considerably. Which one of the following statements is correct? KA2

• J. The smell of hot food is the sensor and the brain is the effector.
• K. The smell of hot food is the receptor and the nasal mucous membranes are the effectors.
• L. The smell of hot food is the reflex and the central nervous system is the effector.
• M. The smell of hot food is the stimulus and the salivary glands are the effectors.