Question 1

After spending several days at a high altitude,where oxygen pressure is low,a person will begin to produce more red blood cells,which enhances the ability of blood to carry oxygen to the tissues.What term best describes this type of response?

Accepted Answer

Physiological acclimatization refers to the body's ability to adapt to changes in the environment, such as the increase in red blood cell production to enhance oxygen-carrying capacity at high altitudes. Developmental acclimatization refers to changes that occur during development or growth, such as a person growing taller to adapt to a colder climate. Positive feedback is a type of feedback loop that amplifies a response, which is not applicable in this scenario. Feedforward regulation refers to the body's ability to anticipate and prepare for changes in the environment, which is also not applicable in this scenario. Evolution refers to changes that occur over generations, which does not explain the individual's response to high altitude.

Question 2

How are endocrine glands and hormones involved in homeostatic reflexes?

Accepted Answer

Endocrine glands can serve as integrating centers in homeostatic reflexes, receiving information and coordinating a response by releasing hormones into the bloodstream. Hormones then act as efferent pathways, carrying the message to target tissues to bring about a response that helps maintain homeostasis.

Question 3

An experimental subject is isolated in an underground room with no windows,no clocks,and no contact with the outside world.Researchers monitoring his behavior observe that he eats breakfast a little bit later each day.What term best describes the subject's biological activity?

Accepted Answer

The subject's biological activity is best described as a free-running rhythm, which occurs when natural environmental cues (like light) are absent, causing the body's internal clock to follow its own cycle rather than the 24-hour day.

Question 4

A protein is found in blood that is produced by the pancreas and acts on receptors of cells in the liver.What type of physiological regulator is it most likely to be?

Accepted Answer

The protein is produced by the pancreas and acts on receptors of cells in a different organ (the liver), which suggests that it is a hormone - a signaling molecule that is secreted into the bloodstream and carries a message to distant target cells.

Question 5

The hormone insulin enhances the transport of glucose into body cells.Its secretion is controlled by a negative feedback system between the concentration of glucose in the blood and the cells that secrete insulin.Which of the following statements is most likely to be correct?

Accepted Answer

Insulin secretion is controlled by negative feedback loop between the concentration of glucose in the blood and the cells that secrete insulin. An increase in blood glucose concentration stimulates the secretion of insulin which enhances the transport of glucose into body cells, thus lowering the blood glucose concentration. Conversely, a decrease in blood glucose concentration will reduce insulin secretion, allowing blood glucose concentration to increase. Therefore, option B is correct.

Question 6

Heart rate is increased by the release of epinephrine by the adrenal medulla into the bloodstream.This is an example of

Accepted Answer

Epinephrine release by the adrenal medulla is an example of endocrine control, as it involves the release of a hormone into the bloodstream to exert its effects on target tissues throughout the body.

Question 7

Which equation is most accurate?

Accepted Answer

C) Extracellular fluid volume - interstitial fluid volume = plasma volume. This equation is most accurate because the extracellular fluid consists of two main components: the interstitial fluid (fluid between cells) and the plasma (the liquid part of blood). Therefore, if you subtract the volume of interstitial fluid from the total extracellular fluid volume, you get the plasma volume.

Question 8

Identify the effectors in this homeostatic reflex: Eating a salt-rich meal increases blood volume and pressure,stretching blood vessel walls.Nerve signals sent to the brainstem stimulate changes in hormonal and neural signaling.The heart rate is slowed,blood vessel walls are relaxed,and the kidneys increase urinary salt.The blood pressure returns toward normal.

Accepted Answer

The effectors in this homeostatic reflex are the heart, blood vessels and kidneys. The heart rate is slowed, blood vessel walls are relaxed and the kidneys increase urinary salt to regulate blood volume and pressure in response to the salt-rich meal. The brainstem and hormonal and neural signaling are part of the reflex, but not the effectors.

Question 9

Eating a bag of salty potato chips without increasing sodium excretion would result in what state?

Accepted Answer

Eating a bag of salty potato chips will increase the intake of sodium, which can only be excreted through the kidneys. If sodium excretion doesn't increase, it means that the body is retaining more sodium than it is eliminating, resulting in a positive sodium balance. This can lead to health problems such as high blood pressure, edema, and heart disease.

Question 10

A burn patient ingests 100 grams of protein per day and loses 110 grams of protein per day due to the injury.What is the overall protein state of the patient?

Accepted Answer

The patient is losing more protein than they are ingesting, resulting in a negative protein balance.

Question 11

What is the location of the internal pacemaker that sets biological rhythms?

Accepted Answer

The suprachiasmatic nucleus (SCN) of the brain is the location of the internal pacemaker that sets biological rhythms, also known as the circadian clock. It receives input from photoreceptors in the eye and regulates a variety of physiological processes, including the sleep-wake cycle, hormone secretion, and metabolism.

Question 12

The interstitial fluid refers to

Accepted Answer

Interstitial fluid is the fluid between the cells in tissues and organs. It is derived from the plasma and surrounds the cells, providing them with nutrients and facilitating waste removal. It is distinct from the fluid within the cells (intracellular fluid) and the plasma.

Question 13

Which one of the following is the correct sequence for a regulatory reflex arc?

Accepted Answer

The correct sequence for a regulatory reflex arc is stimulus, receptor, afferent pathway, integrating center, efferent pathway, and effector. Choice C follows this sequence correctly. The stimulus is detected by the receptor, and the sensory information travels through the afferent pathway to the integrating center. The integrating center processes the information and decides on the appropriate response, which is sent through the efferent pathway to the effector, causing a response to the original stimulus.

Question 14

How is autocrine regulation best described?

Accepted Answer

Autocrine regulation occurs when a cell produces and secretes chemical regulators that affect the same cell or cells of the same type in the immediate vicinity. This self-regulation can contribute to important physiological processes such as development, immune responses, and tissue repair.

Question 15

What is a hormone?

Accepted Answer

The definition of a hormone is a chemical regulator secreted from an endocrine gland that travels through the bloodstream to affect target cells. This definition matches option E.

Question 16

Some neurons in the vagus nerve have synaptic connections to sinoatrial cells (pacemaker)in the heart.These neurons secrete acetylcholine,which ultimately results in a decreased heart rate.This is an example of

Accepted Answer

This is an example of neural control, where neurons in the vagus nerve send signals to the heart to decrease heart rate through the secretion of acetylcholine. Endocrine control involves the release of hormones into the bloodstream to regulate body functions, exocrine control involves the secretion of substances outside of the body, hormonal control is another term for endocrine control, and paracrine control involves the release of signaling molecules that act locally on nearby cells.

Question 17

The tall slender body shape that helps to dissipate heat in people native to equatorial regions is an example of

Accepted Answer

The tall slender body shape in people native to equatorial regions is an adaptation, which is a genetic change that helps an organism better survive and reproduce in a specific environment. This adaptation helps to dissipate heat more effectively in hot and humid environments. Acclimatization refers to the physiological adjustment an individual makes within their lifetime to better cope with environmental stress, while set point resetting refers to the body's ability to adjust its internal temperature set point to deal with changing external temperatures. Homeostasis refers to the maintenance of a stable internal environment despite external changes, and phase shift refers to a change in the timing of a biological rhythm.

Question 18

Circadian rhythms are biological rhythms with what main characteristic?

Accepted Answer

Circadian rhythms refer to biological rhythms that repeat approximately every 24 hours, like the daily spikes in hormone secretion. These rhythms are critical for regulating important physiological functions, including sleep-wake cycles, hormone secretion, and metabolism.

Question 19

Which best describes how the total body balance of any chemical substance is determined?

Accepted Answer

The total body balance of a chemical substance is determined by the difference between the amount of substance lost from the body (through excretion, sweating, etc.) and the amount gained by the body (through ingestion, absorption, etc.). This equation is called the mass balance equation and is fundamental in pharmacokinetics and toxicology. The rate of production, secretion, or metabolism of the substance may play a role in determining the total body balance, but ultimately it is the difference between gains and losses that determines it.

Question 20

The internal environment of the body refers to

Accepted Answer

The internal environment of the body refers to the plasma, the interstitial fluid, and the intracellular fluid combined. These three fluids make up the extracellular fluid and the intracellular fluid, which together create the internal environment of the body.

Quiz 1: Homeostasis: A Framework for Human Physiology

After spending several days at a high altitude,where oxygen pressure is low,a person will begin to produce more red blood cells,which enhances the ability of blood to carry oxygen to the tissues.What term best describes this type of response?