Body Fluids Overview

Questions and Answers

What percentage of water typically constitutes the body fluids in a 70 kg young man?

70%

60% (correct)

50%

80%

Which of the following correctly describes a characteristic role of plasma proteins?

Transporting lipids in the blood (correct)

Facilitating carbohydrate digestion

Regulating blood pH balance

Delivering oxygen to tissues

What is the main principle behind measuring body fluid compartments?

Using osmolarity as a measuring parameter (correct)

Direct sampling of each compartment

Estimation based on total body weight

Adjusting based on age and gender differences

Which type of blood cell is primarily responsible for oxygen transportation?

Red blood cells Signup and view all the answers

How do osmolarity and equilibria act across membranes?

They maintain homeostasis by balancing solute concentrations. Signup and view all the answers

What is a common characteristic of the main types of cells found in blood?

All perform distinct specialized functions. Signup and view all the answers

Which fluid is NOT included as a transcellular fluid?

Blood plasma Signup and view all the answers

What is the correct formula to calculate volume (V) in the dilution method?

V = S/C Signup and view all the answers

Which of the following substances is suitable for measuring plasma volume?

Evans Blue Signup and view all the answers

In measuring total body water (TBW), which substance would be the most appropriate?

3H2O Signup and view all the answers

Which characteristic must a substance possess to be used for measuring extracellular space (ECS)?

It must not enter cells easily. Signup and view all the answers

When adding 20 red molecules in the example provided, what is the resulting total volume if the concentration measured is 2 red per ml?

10 ml Signup and view all the answers

Which of the following is a requirement for a substance used in dilution methods?

It must distribute in the space of interest. Signup and view all the answers

What is an example of a substance used for measuring the extracellular space that fits the required criteria?

24Na Signup and view all the answers

What percentage of total body weight is represented by plasma space?

5% Signup and view all the answers

How many liters of interstitial fluid are present in the extracellular space?

10.5 L Signup and view all the answers

Which body fluid compartment contains the majority of total body water?

Intracellular space (ICS) Signup and view all the answers

What is the estimated total body water (TBW) in liters for an average individual?

42 L Signup and view all the answers

If the blood volume accounts for 8% of body weight, how many liters does it approximately represent in a 70 kg individual?

5.5 L Signup and view all the answers

What is the approximate water content of lean tissue expressed in liters per kilogram?

0.71 L/Kg Signup and view all the answers

Which of the following is NOT one of the main body fluid compartments?

Intravascular fluid Signup and view all the answers

What volume of blood constitutes the plasma space in relation to total blood volume?

3.5 L Signup and view all the answers

What is the approximate total quantity of plasma proteins per litre?

70 g/litre Signup and view all the answers

Which plasma protein is primarily responsible for the transport and buffering of pH?

Albumin Signup and view all the answers

What is the approximate concentration of fibrinogen in plasma?

3 g/litre Signup and view all the answers

Which of the following FUNCTIONS do α, β, and γ globulins primarily serve?

Haemostasis and immune response Signup and view all the answers

What is the osmotic pressure of plasma that influences capillary fluid transport?

25 mmHg Signup and view all the answers

What characterizes the interstitial fluid's protein content compared to plasma?

Lower protein content Signup and view all the answers

Which of the following best describes anaemia?

Low red blood cell count or hemoglobin Signup and view all the answers

Which body fluid compartment does NOT represent a typical measurement in human physiology?

Gastric fluid Signup and view all the answers

What is the primary difference between osmolarity and osmolality?

Osmolarity measures solute concentration per litre of solution. Signup and view all the answers

What is the typical osmolarity of plasma?

290 mosmol/litre Signup and view all the answers

Which of the following statements best describes isotonic solutions?

They have the same tonicity as human plasma. Signup and view all the answers

What factor contributes to crystalloid osmotic pressure?

Small diffusible ions Signup and view all the answers

How does a 1% difference in osmolarity between extracellular and intracellular fluids affect pressure?

It exerts about 50 mmHg pressure across the membrane. Signup and view all the answers

Why must intra- and extracellular osmolarity remain equal?

To prevent cell membrane rupture and maintain cell integrity. Signup and view all the answers

Study Notes

Body Fluids

Total body water (TBW) in a 70 kg young man is approximately 42 L, constituting about 60% of body weight.
Body fluid compartments include intracellular space (ICS), interstitial space, and plasma.
Blood volume represents about 8% of body weight, approximately 5.5 L, with plasma volume at about 3.5 L.
Intracellular space contains around 28 L of water; lean tissue’s water content is approximately 0.71 L/kg.
Other compartments, known as transcellular fluids, include cerebrospinal fluid (CSF), synovial fluid, and amniotic fluid, totaling about 150 mL for CSF.

Measurement of Body Fluid Compartments

The dilution method is used to measure fluid compartments; a known amount of substance is added to an unknown volume, allowing calculation of volume via concentration.
Plasma volume markers include large molecules like Evans Blue and albumin, while extracellular space (ECS) can be measured using substances like 24Na and sucrose.

Osmolarity and Osmotic Pressure

Osmolarity is expressed in osmoles per liter (osmolality in osmoles per kg), with plasma osmolarity averaging around 290 mosmol/L.
A 1% difference in osmolarity between extra- and intracellular fluids could exert significant pressure across the cell membrane, potentially over 50 mmHg.
Isotonic solutions, such as normal saline (0.9% NaCl), have the same tonicity as plasma, critical for maintaining fluid balance.

Plasma Proteins

Plasma protein concentration averages around 70 g/L; major constituents include albumin (48 g/L), which regulates oncotic pressure and transports various substances.
Globulins (α, β, γ) varying between 0.7-13 g/L play roles in haemostasis, immune function, and transport.
Fibrinogen (3 g/L) is essential for blood clotting.

Introduction to Blood Cells

Emphasis on understanding the classification and functions of blood cells, including normal red blood cell (RBC) and white blood cell (WBC) counts, along with hemoglobin (Hb) levels.
"Anaemia" refers to a deficiency in the number or quality of red blood cells or hemoglobin, impacting oxygen transport.

Learning Outcomes

Identifying the body fluid compartments and their volumes in adults.
Explaining the dilution method for measuring fluid compartments and key plasma constituents.
Understanding osmolarity’s role in fluid movement and its physiological implications.
Classifying plasma proteins and their functional importance.

Additional Notes

The textbook for reference includes "Vander's" with optional readings from "Cardiovascular System at a Glance" and other physiology resources.
Understanding haematopoiesis and blood cell development is crucial for full comprehension of blood physiology.

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Description

This quiz covers key concepts about body fluids, including total body water distribution and the various compartments such as intracellular and interstitial spaces. Understand the significance of blood volume and plasma in relation to body weight. Test your knowledge on how these components interact and their importance to overall health.