【PEP】Senior Biology, Selective Compulsory, Volume 1: Stress Response: How Your Body "Senses" and "Acts"

The Body's "Buffer Zone": The Internal Environment

Imagine your cells are delicate creatures living in the deep sea, unable to directly contact the ever-changing external world. Theplasma, interstitial fluid, and lymphextracellular fluids, which make up theinternal environmentserve as their "liquid home." It is through this environment that the body's cells exchange materials with the outside world.

Sensing and Acting: The Logic of the Stress Response

When you suddenly encounter a barking dog, this "intense stimulus" instantly disrupts the body's calm. Your nervous system rapidly shifts from sensing to action. The cerebral cortex registers fear,the sympathetic nervous systemdominates instantly, triggering an accelerated heartbeat, rapid breathing, and the breakdown of liver glycogen into blood sugar for energy. This temporary deviation from resting levels is essentially a defensive "dynamic balance" strategy adopted by the living system—as an open, holistic system—to maintaininternal environment homeostasis.

QUESTION 1

In an experimental setup, if the afferent nerve of the reflex arc is severed and the receptor is stimulated, what phenomenon is observed?

Can move, feels the needle prick

Can move, no feeling from the needle prick

Cannot move, feels the needle prick

Cannot move, no feeling from the needle prick

QUESTION 2

The internal environment refers to the fluid environment in which the body's cells survive. Which of the following components primarily constitute it?

plasma, interstitial fluid, and lymph

Blood, sweat, and digestive juices

Intracellular fluid, plasma, and interstitial fluid

Blood, urine, and extracellular fluid

QUESTION 3

When the body is in a state of stress (such as encountering danger), which part of the autonomic nervous system plays the primary role?

Parasympathetic nervous system, slowing the heart rate

Sympathetic nervous system, enhancing digestive function

Parasympathetic nervous system, constricting the bronchi

Sympathetic nervous system, accelerating heart rate and increasing metabolism

QUESTION 4

Regarding internal environment homeostasis, which of the following statements is incorrect?

Homeostasis is a dynamic balance, not absolute stillness

Homeostasis is achieved through the body's automatic regulation

Any fluctuation in the physicochemical properties of the internal environment indicates illness

Homeostasis is a necessary condition for normal life activities

QUESTION 5

What is the biological significance of shivering in the stress response?

Increase heat production to maintain body temperature balance

Reduce heat dissipation to prevent heat loss

Promote digestion to provide energy

Dilate blood vessels to increase blood flow