Blood Functions Overview

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Questions and Answers

What is one of the primary functions of blood related to transportation?

Heat preservation during cold exposure

Distribution of oxygen and carbon dioxide (correct)

Initiation of immune response

Regulation of hormone levels

Which component of blood contributes significantly to the regulation of pH levels?

White blood cells

Bicarbonate ions (HCO3-) (correct)

Proteins in the plasma

Red blood cells

How does blood help in temperature regulation?

By transporting metabolic wastes

Through its high specific heat (correct)

By altering blood pressure

By increasing oxygen delivery

What role do immune cells in the blood play?

They protect against pathogens Signup and view all the answers

What effect does consuming a salty meal have on blood volume?

Raises both extracellular and blood volume Signup and view all the answers

What is the function of oncotic pressure in capillary beds?

Facilitates the exchange of nutrients and gases Signup and view all the answers

What is the primary component of plasma?

Water Signup and view all the answers

Which process in blood helps in clotting during hemorrhage?

Coagulation of plasma proteins Signup and view all the answers

What does the buffy coat in a centrifuged blood sample consist of?

White blood cells and platelets Signup and view all the answers

What determines blood pressure in the circulatory system?

Total blood volume in the circulatory system Signup and view all the answers

What is the main effect of increased body temperature on blood vessels?

Dilates vessels to release heat Signup and view all the answers

What proportion of blood volume is made up of red blood cells?

About 45% Signup and view all the answers

Which solute is the largest component in blood plasma?

Proteins Signup and view all the answers

Which of the following is NOT a formed element of blood?

Plasma Signup and view all the answers

What percentage of total body fluids does blood account for?

8% Signup and view all the answers

Which protein in the blood contributes to osmotic pressure?

Albumin Signup and view all the answers

What percentage of formed elements in blood are red blood cells (RBCs)?

99% Signup and view all the answers

Which type of white blood cells is most abundant in the human body?

Neutrophils Signup and view all the answers

What is the normal range for red blood cell (RBC) count per microliter in males?

4.8 - 5.4 million Signup and view all the answers

What physiological condition is indicated by a decreased blood pH?

Acidosis Signup and view all the answers

What key factor affects variations in blood volume based on body size?

Body surface area Signup and view all the answers

Which system controls the reabsorption or excretion of sodium to regulate blood volume?

Renin-Angiotensin-Aldosterone System (RAAS) Signup and view all the answers

What is the normal platelet count per microliter in blood?

150,000 - 400,000 Signup and view all the answers

How do the kidneys contribute to maintaining blood pressure?

By altering sodium reabsorption Signup and view all the answers

What is the primary physiological role of ADH (Anti-Diuretic Hormone)?

Conserves water during low blood pressure Signup and view all the answers

Which blood sampling method is the most common?

Venipuncture Signup and view all the answers

Why is it important to obtain a blood sample from an artery to measure oxygen saturation?

Arterial oxygen saturation is more accurate Signup and view all the answers

What is the appearance of red blood cells (RBCs) under an electron microscope?

Biconcave disc Signup and view all the answers

What distinguishes interstitial fluid from other components of extracellular fluid (ECF)?

It is continuously renewed by blood Signup and view all the answers

Which of the following correctly describes the structure of red blood cells (RBCs)?

Lacks a nucleus, forming a biconcave shape Signup and view all the answers

Which statement about the differences between venous and arterial blood is true?

The red blood cell count is similar, but gas concentrations differ Signup and view all the answers

What role does plasma play in blood?

It acts as a liquid connective tissue and carries nutrients Signup and view all the answers

Study Notes

Blood Functions

Transport:
- Carries oxygen, carbon dioxide, nutrients, waste products, hormones.
- Wastes are transported to kidneys, liver, and lungs for elimination.
- Blood is part of the extracellular compartment, along with interstitial fluid.
Regulation:
- Maintains pH, temperature, blood pressure, volume, and osmotic pressure.
- pH regulation is mediated by bicarbonate ions (HCO3-), electrolytes, and proteins.
- Temperature regulation is facilitated by blood's high specific heat capacity (due to water content).
- Blood pressure and volume are closely related: increased blood volume leads to increased blood pressure.
- Osmotic pressure is controlled by proteins and electrolytes, influencing fluid movement between compartments.
Protection:
- Clotting prevents excessive bleeding through coagulation.
- Immune cells (WBCs), complement system, and immunoglobulins protect against pathogens.
- Proteins in blood help transport ions, preventing interactions with cells that could alter their structure and function.

Blood Composition

Plasma:
- Mostly water (91.5%).
- Contains solutes: gases, proteins (albumin, fibrinogen, globulins), and electrolytes (mainly NaCl).
- Albumin is the major protein and contributes to blood's osmotic pressure.
Formed Elements:
- Mostly red blood cells (RBCs), constituting 99% of formed elements.
- White blood cells (WBCs) and platelets make up the remaining 1%.
- Normal RBC count: 4.8-5.4 million/µL (higher in males).
- Normal WBC count: 5000-10000/µL.
- Normal platelet count: 150,000-400,000/µL.
- Most abundant WBCs are neutrophils, followed by lymphocytes, monocytes, eosinophils, and basophils. Each type has specific functions.

Blood Physical Characteristics

Mimics water, as water is the solvent of blood.
Temperature: 38°C (slightly higher than oral or rectal temperature).
Viscosity: More viscous than water (sticky).
pH: Slightly alkaline (7.35-7.45), maintained within a narrow range.
Color: Varies from bright red (oxygenated) to dark red (deoxygenated).
Blood volume: 5-6 L in males, 4-5 L in females (varies with body size).

Blood Volume Regulation

Hormonal regulation: RAAS, ANP, ADH.
RAAS (Renin-Angiotensin-Aldosterone System): Controls sodium (Na+) levels, influencing water reabsorption or excretion by kidneys.
ANP (Atrial Natriuretic Peptide): Increases Na+ excretion, reducing blood pressure (acts as a natural antihypertensive).
ADH (Anti-Diuretic Hormone) or Vasopressin: Decreases urine production, conserving water in cases of low blood pressure or dehydration.

Blood Sampling

Different types of blood sampling tubes are available, each suited for specific laboratory tests.
Common procedures:
- Venipuncture: Most common and easiest, obtained from veins.
- Finger stick or heel stick: Used for capillary blood samples.
- Arterial stick: Used for arterial blood samples, essential for accurate oxygen saturation measurements.

Formed Elements Under Microscopes

Light microscope:
- RBCs appear as biconcave discs.
- WBCs appear as large, multi-lobed cells with varying colors (blue to red).
- Platelets appear as small, fragmented cells.
Electron microscope:
- Reveals the biconcave structure of RBCs, which increases surface area and is possible because RBCs lack a nucleus.

Interstitial Fluid

Part of the extracellular fluid (ECF) continuously renewed and modified by blood.
Provides the environment for cells to acquire nutrients and eliminate waste products.

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Description

This quiz explores the essential functions of blood, focusing on its roles in transport, regulation, and protection. Questions cover how blood carries various substances, maintains homeostasis, and protects the body from pathogens. Test your knowledge on the critical functions that blood performs in human physiology.