Circulatory System Overview

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Questions and Answers

What is the primary function of the circulatory system?

Production of hormones

Transport of nutrients and gases (correct)

Defense against infections

Regulation of body temperature

What types of cells make up the formed elements of blood?

Erythrocytes, platelets, and leukocytes (correct)

Leukocytes, erythrocytes, and macrophages

Neutrophils, erythrocytes, and plasma

Erythrocytes, leukocytes, and plasma cells

Which component of blood is responsible for transporting oxygen?

Platelets

White blood cells

Red blood cells (correct)

Plasma

What percentage of blood plasma is made up of water?

90% (A) Signup and view all the answers

What are the three main proteins found in blood plasma?

Albumin, globulin, and fibrinogen (D) Signup and view all the answers

Which of the following is NOT a function of blood?

Production of energy (C) Signup and view all the answers

What is the characteristic shape of red blood cells?

Biconcave, disc-shaped (B) Signup and view all the answers

What type of muscle comprises the heart?

Cardiac muscle (C) Signup and view all the answers

Which of the following functions is NOT associated with blood?

Hormone synthesis (B) Signup and view all the answers

What is automaticity in the context of the heart?

Ability to contract without external nervous stimulation (B) Signup and view all the answers

What is the primary function of hemoglobin in the blood?

Transport of oxygen and carbon dioxide (D) Signup and view all the answers

Which component is produced in response to low oxygen levels?

Erythropoietin (C) Signup and view all the answers

What happens to red blood cells after their life cycle is over?

They are destroyed in the spleen (D) Signup and view all the answers

What is the normal hematocrit value for men in million cells/mm3?

5 million (B) Signup and view all the answers

Which vitamin is essential for DNA synthesis in red blood cell production?

Vitamin B12 (C) Signup and view all the answers

What percentage range of blood volume do neutrophils comprise?

60 – 70 % (B) Signup and view all the answers

What condition refers to a reduction of hemoglobin or red cell concentration in the blood?

Anemia (B) Signup and view all the answers

Which type of white blood cell plays a role in ending allergic reactions?

Eosinophils (D) Signup and view all the answers

What form is the majority of carbon dioxide transported in the blood?

As HCO3- (bicarbonate) (D) Signup and view all the answers

Which type of white blood cell is most numerous in the body?

Neutrophils (B) Signup and view all the answers

Study Notes

Introduction

The circulatory system is a transport system for the body.
It plays a role in body defenses and the coagulation process.
It also helps regulate body temperature.
The circulatory system is made up of the cardiovascular system:
- Blood: the transport medium
- Blood vessels: arteries, veins, and capillaries
- Heart: circulates blood through the vessels
- The heart is a hollow, muscular organ.
- The heart is made of cardiac muscle.
- The heart's chambers contract simultaneously due to depolarization.
- The heart is capable of automaticity.

Blood

Blood is a type of connective tissue.
Blood is a complex mixture of cells, chemicals, and fluid.
Blood transports substances throughout the body and helps to maintain a stable internal environment.
Blood contains:
- Red blood cells
- White blood cells
- Platelets (formed elements)
- Plasma

Blood Plasma

Blood plasma is the straw-colored, sticky fluid portion of blood.
Plasma is approximately 90% water and contains:
- Ions, including Na and Cl ions
- Nutrients, including sugars, amino acids, lipids, cholesterol, vitamins and trace elements.
- Three main proteins:
  - Albumin (60%)
  - Globulin (35%)
  - Fibrinogen (4%)
- Dissolved Gases, including O2 and CO2
- Waste Products, including other protein wastes such as urea and bilirubin

Formed Elements

Blood cells are formed elements and include:
- Erythrocytes
- Leukocytes
- Platelets

Hematopoiesis

Hematopoiesis is the process of blood cell formation.

Red Blood Cells (RBCs)

Erythrocytes are the most abundant type of blood cell (99%).
RBCS structure:
- Biconcave, anucleate, and 8 m in diameter.
- Components:
  - Hemoglobin
  - Lipids
  - ATP
  - Carbonic anhydrase

Red Blood Cell Function

RBCs transport O2 and CO2.
RBCs transport the majority of CO2 as HCO3-.
RBCs play a role in pH homeostasis.
- Carbonic anhydrase converts CO2 and H2O to HCO3- and H+.
RBCs bend to pass through small capillaries.
RBCs are destroyed in the spleen.
Phagocytic WBC’s clear the debris from RBC destruction.

Hematocrit

Hematocrit is the percentage of red blood cells in blood.
Men have 5 million cells/mm3 of blood.
Women have 4.5 million cells/mm3 of blood.

Regulation of Red Blood Cells

The total number of RBCs remains relatively constant due to a negative feedback mechanism involving erythropoietin.
Erythropoietin is released from the kidneys and liver in response to the detection of low oxygen levels.

Dietary Factors Affecting Red Blood Cell Production

Vitamins B12 and folic acid are needed for DNA synthesis.
Iron is necessary for hemoglobin synthesis.

Red Blood Cell Disease

Anemia is a reduction in hemoglobin or red blood cell concentration in blood.
Polycythemia is an excess of erythrocytes.
- Often caused by cancer, tissue hypoxia, and dehydration.
- However, polycythemia can occur naturally at high elevations.

White Blood Cells

White blood cells are also known as leukocytes.
WBCs function to protect the human body from infection and disease.
- Neutrophils: 60–70% of WBCs: have multilobed nuclei; blue granules; phagocytize and destroy bacteria
- Eosinophils: 2–4% of WBCs: have bilobed nuclei; red or yellow granules containing digestive enzymes; play a role in ending allergic reactions.
- Basophils: have bilobed nuclei; contain histamine and heparin.

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Description

Explore the intricacies of the circulatory system, including its components such as the heart, blood, and blood vessels. Understand how blood functions to transport substances and maintain homeostasis in the body. This quiz covers key concepts from anatomy and physiology related to circulation.