Cuestionario: Homeostasis and Regulation Systems — 10 preguntas

1. In response to a significant decrease in body temperature, which sequence correctly illustrates the homeostasis mechanism involved?

A. Receptors in the muscles detect the cold, signal is sent to the brain, which then causes the body to sweat to cool down.

B. Receptors in the brain detect the cold, signal is sent to the skin, which then releases heat by expanding blood vessels.

C. Receptors in the skin detect the cold, signal is sent to the muscles, which then produce sweat to cool the body.

D. Receptors in the skin detect the cold, signal is sent to the brain, muscles shiver to generate heat.

Answer: (D)

Explicación

The correct sequence involves receptors in the skin detecting the cold, sending signals to the brain (a coordination centre), which then activates effectors such as muscles to shiver and generate heat, thereby counteracting the temperature decrease. The other options incorrectly describe the roles of receptors, effectors, or the responses involved in temperature regulation.

2. What is the hormonal system in the body primarily responsible for?

A. Controlling voluntary movements through nerve signals

B. Providing immediate responses to external stimuli via nerve cells

C. Regulating body functions through the secretion of chemical messengers into the bloodstream

D. Transmitting electrical impulses rapidly to muscles and glands

Answer: (C)

Explicación

The hormonal system, also known as the endocrine system, primarily regulates body functions by secreting hormones—chemical messengers—into the bloodstream, which then travel to target organs to produce effects. This distinguishes it from the nervous system, which uses electrical impulses for rapid responses.

3. Which component of the reflex arc is responsible for transmitting signals between nerve cells?

A. Effector muscle

B. Myelin sheath

C. Receptor cell

D. Synapse

Answer: (D)

Explicación

The synapse is the part of the reflex arc responsible for transmitting signals between nerve cells (neurones). It allows chemical signals to cross the gap between neurones, ensuring the impulse continues its pathway rapidly, which is essential for the quick response in reflex actions.

4. What is a direct consequence of the pancreas secreting insulin when blood glucose levels are high?

A. Blood glucose levels increase

B. Blood glucose levels decrease

C. Blood glucose levels fluctuate unpredictably

D. Blood glucose levels remain unchanged

Answer: (B)

Explicación

When the pancreas secretes insulin, it causes glucose to move from the blood into muscle and liver cells, reducing blood glucose levels. This negative feedback helps maintain normal blood glucose levels.

5. What is the specific role of luteinising hormone (LH) in the female reproductive cycle?

A. It causes the lining of the uterus to thicken

B. It triggers ovulation, the release of an egg from the ovary

C. It inhibits the release of FSH from the pituitary gland

D. It stimulates the maturation of eggs in the ovaries

Answer: (B)

Explicación

LH's primary role in the reproductive cycle is to trigger ovulation, which is the release of an egg from the ovary. This is explicitly stated as the function of LH in the context of reproductive hormones.

6. What is the main role of contraception methods?

A. To prevent fertilization or implantation, thereby avoiding pregnancy

B. To promote ovulation and increase fertility

C. To regulate hormone levels for better reproductive health

D. To enhance the body's natural reproductive cycle

Answer: (A)

Explicación

The primary purpose of contraception methods is to prevent fertilization or implantation, which stops pregnancy from occurring. While some methods may influence hormone levels or reproductive health, their main function is to serve as a barrier or inhibitor against conception.

7. When was the first successful in vitro fertilisation (IVF) birth achieved?

A. 1990

B. 1985

C. 1967

D. 1978

Answer: (D)

Explicación

The first successful IVF birth, of Louise Brown, occurred in 1978, marking a major milestone in fertility treatments. The other years are plausible but incorrect milestones: 1967 predates IVF's success, 1985 and 1990 are after the event but do not correspond to the first successful case.

8. How do dominant and recessive alleles differ in their effect on phenotype expression?

A. Dominant alleles are only inherited from the mother, while recessive alleles are only inherited from the father

B. Dominant alleles are expressed if at least one copy is present, whereas recessive alleles are only expressed if two copies are present

C. Both dominant and recessive alleles are expressed equally regardless of the number of copies

D. Dominant alleles only affect phenotype when present in two copies, while recessive alleles affect phenotype even with one copy

Answer: (B)

Explicación

Dominant alleles are expressed in the phenotype if at least one copy is present, whereas recessive alleles only affect the phenotype if two copies are present (homozygous recessive). This is the fundamental difference in how they influence observable traits.

9. Who proposed the theory of natural selection as a mechanism for evolution?

A. Charles Darwin

B. Gregor Mendel

C. Alfred Russel Wallace

D. Jean-Baptiste Lamarck

Answer: (A)

Explicación

Charles Darwin is credited with proposing the theory of natural selection in his 1859 publication 'On the Origin of Species.' Lamarck suggested inheritance of acquired characteristics, Mendel developed genetics, and Wallace independently conceived a similar idea but Darwin is primarily credited.

10. How can applying pollution control measures benefit biodiversity within ecosystems?

A. Increasing fertilizer use to support plant growth

B. Reducing pollutants to improve habitat quality

C. Removing all human activity from natural areas

D. Introducing new predator species to control pests

Answer: (B)

Explicación

Applying pollution control reduces harmful substances in the environment, which helps maintain healthy habitats and supports diverse species, thereby benefiting biodiversity. Introducing new predators can disrupt existing balances, removing all human activity is often impractical, and increasing fertilizer use can cause nutrient pollution, harming ecosystems.