Physiology Chapter on Homeostasis Regulation

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Questions and Answers

What role do the liver and pancreas play in the regulation of the extracellular fluid?

Maintaining glucose concentration (correct)

Controlling carbon dioxide concentration

Regulating oxygen concentration

Regulating blood vessel dilation

What physiological response occurs when arterial pressure increases above normal?

Increased sympathetic nervous system activity

Dilation of blood vessels

Inhibition of the vasomotor center

Increased nerve impulses from the baroreceptors (correct)

How does the body respond to elevated arterial pressure through the baroreceptor system?

Increasing carbon dioxide concentration

Sending more impulses to the vasomotor center

Decreasing sympathetic nervous system activity (correct)

Increasing heart rate

Where are baroreceptors located in the body?

In the bifurcation region of the carotid arteries Signup and view all the answers

What role does hemoglobin play in the regulation of oxygen concentration?

Combines with oxygen in the lungs Signup and view all the answers

What is the effect of decreased sympathetic activity on the cardiovascular system?

Dilation of blood vessels Signup and view all the answers

What substance's concentration is specifically regulated by the kidneys?

Ion concentrations such as sodium and potassium Signup and view all the answers

Which part of the brain receives signals from the baroreceptors?

Medulla Signup and view all the answers

What is the normal pH value of venous blood?

7.4 Signup and view all the answers

Which constituent of extracellular fluid has a normal range of 135–145 mmol/L?

Sodium ion Signup and view all the answers

What happens to carbon dioxide concentration in the body when the temperature increases?

It causes a vicious cycle of increasing cellular metabolism Signup and view all the answers

What is the approximate short-term nonlethal limit of glucose concentration in mg/dl?

1500 Signup and view all the answers

What is the body temperature range that is considered normal in degrees Fahrenheit?

98–98.8 Signup and view all the answers

Which ion has a normal value of 1.2 mmol/L in extracellular fluid?

Calcium ion Signup and view all the answers

What is the lethal upper limit for carbon dioxide concentration in mm Hg?

80 Signup and view all the answers

How much can body temperature increase before causing significant issues?

11°F Signup and view all the answers

What is adaptive control primarily characterized as?

Delayed negative feedback Signup and view all the answers

What element is crucial for the maintenance of homeostasis in the body?

Concentration of potassium ions Signup and view all the answers

Which of the following does NOT contribute to physiological variability?

Mechanical efficiency Signup and view all the answers

What primarily determines a person’s physiological state throughout the day?

Daily activities and movement Signup and view all the answers

What is the significance of homeostasis for individual cells?

Each cell relies on homeostasis to function properly. Signup and view all the answers

What happens when one or more functional systems lose their capability?

All cells begin to suffer. Signup and view all the answers

How many cells are approximately organized within the body?

35 to 40 trillion Signup and view all the answers

What role do organs play in the body's physiological processes?

They contribute to the overall maintenance of homeostasis. Signup and view all the answers

Which components primarily make up the cell membrane?

Phospholipids and cholesterol Signup and view all the answers

What is the primary function of glycogen within the cell?

To serve as a rapid energy source Signup and view all the answers

Which structure is involved in synthesizing proteins within the cell?

Ribosomes Signup and view all the answers

Which organelle is responsible for modifying and packaging proteins?

Golgi apparatus Signup and view all the answers

What is the primary role of triglycerides in cells?

To serve as energy reserves Signup and view all the answers

Which of the following organelles is primarily involved in ATP production?

Mitochondrion Signup and view all the answers

Which structure is not directly involved in the cell membrane formation?

Microfilaments Signup and view all the answers

What is the function of lysosomes in the cell?

Digestion of waste materials Signup and view all the answers

What is considered extreme dysfunction in the body?

Causes death Signup and view all the answers

What factors contribute to variability in 'normal' physiological values across individuals?

All of the above Signup and view all the answers

What average body weight does the current American male now exceed?

88 kg Signup and view all the answers

In terms of physiological functions, which statement is generally accurate?

Many discussions focus solely on male physiology. Signup and view all the answers

How have average body weights changed over the past 40 to 50 years in industrialized countries?

Increased substantially Signup and view all the answers

Which of the following physiological functions is often discussed differently in males and females?

Reproductive and hormonal functions Signup and view all the answers

What is a common misconception about physiological discussions regarding the average body?

They typically represent a lean adult male. Signup and view all the answers

Which of the following factors is NOT mentioned as influencing physiological variability?

Cognitive abilities Signup and view all the answers

Study Notes

Carbon Dioxide Concentration Regulation

The respiratory system regulates carbon dioxide concentration in the extracellular fluid.
The lungs expel carbon dioxide from the body, decreasing its concentration.
Increased carbon dioxide concentration triggers an increase in respiration to reduce its level.
Conversely, decreased carbon dioxide concentration results in decreased respiration to increase its level.

Glucose Concentration Regulation

The liver and pancreas control glucose concentration in the extracellular fluid.

Electrolyte Concentration Regulation

The kidneys regulate the concentration of hydrogen, sodium, potassium, phosphate, and other ions in the extracellular fluid.

Arterial Blood Pressure Regulation

The baroreceptor system is a rapid-acting control mechanism for blood pressure.
Baroreceptors located in the carotid arteries and aortic arch sense stretch in the arterial walls.
Increased arterial pressure stretches the baroreceptors, which send signals to the medulla of the brain.
These signals inhibit the vasomotor center in the medulla, leading to decreased sympathetic nervous system activity.
Decreased sympathetic activity causes blood vessel dilation and reduced heart pumping, returning arterial pressure toward normal.

Oxygen Concentration Regulation

Oxygen is crucial for cellular reactions.
Hemoglobin, a molecule in red blood cells, binds to oxygen in the lungs and transports it throughout the body.

Extracellular Fluid Constituents and Values

The extracellular fluid contains vital components, including oxygen, carbon dioxide, sodium, potassium, calcium, chloride, bicarbonate, glucose, and other ions.
These components are meticulously regulated to maintain homeostasis.

Important Constituent Values

Oxygen (venous) - Normal value: 40 mm Hg, Normal range: 25–40 mm Hg.
Carbon dioxide (venous) - Normal value: 45 mm Hg, Normal range: 41–51 mm Hg.
Sodium ion - Normal value: 142 mmol/L, Normal range: 135–145 mmol/L.
Potassium ion - Normal value: 4.2 mmol/L, Normal range: 3.5–5.3 mmol/L.
Calcium ion - Normal value: 1.2 mmol/L, Normal range: 1.0–1.4 mmol/L.
Chloride ion - Normal value: 106 mmol/L, Normal range: 98–108 mmol/L.
Bicarbonate ion - Normal value: 24 mmol/L, Normal range: 22–29 mmol/L.
Glucose - Normal value: 90 mg/dl, Normal range: 70–115 mg/dl.
Body temperature - Normal value: 98.4 °F (37.0°C), Normal range: 98–98.8 °F (37–37.1°C).
Acid–base (venous) - Normal value: 7.4, Normal range: 7.3–7.5.

Homeostasis and Automaticity of the Body

Homeostasis is the maintenance of a stable internal environment crucial for cell survival.
The body functions as a coordinated system of cells and organs working together to maintain homeostasis.
Each organ contributes to the stability of the extracellular fluid, the internal environment.
Cells thrive in a stable internal environment and contribute to its maintenance. This reciprocal interplay provides the body's automaticity.
Dysfunctional systems disrupt homeostasis, leading to sickness or death.

Physiological Variability

Physiological variables can differ significantly among individuals and even within the same individual over time based on numerous factors, including age, sex, genetics, environment, and diet.
Although some variables are tightly regulated, others exhibit significant variability.
The 70-kg young, lean male is often used as a reference for physiological functions, but actual values may vary.
Body weight has significantly increased worldwide, requiring consideration when interpreting data.
While male physiology is often used as a reference, there are notable differences in male and female physiology.

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Description

This quiz explores the regulation of various concentrations in the extracellular fluid, including carbon dioxide, glucose, and electrolytes. Additionally, it covers arterial blood pressure regulation via the baroreceptor system. Test your understanding of these physiological processes and their importance in maintaining homeostasis.