BS161: Lecture 3 - Cardiovascular System

What does the Cardiovascular System consist of?

Pump, conducting system, fluid medium

What is the pump in the cardiovascular system?

The heart

What is the conducting system in the cardiovascular system?

Blood vessels

What is the fluid medium in the cardiovascular system?

Blood

What is the Fluid Medium?

Specialised fluid of connective tissue, contains cells suspended in a fluid matrix

What is the role of Blood relating to transport?

Transports materials to and from cells

What kind of materials does Blood transport?

Oxygen and Carbon Dioxide, Nutrients, Hormones, Immune System components, Waste Products

What is the role of Blood relating to pH?

Regulation of pH and ions

What is the role of Blood relating to defense?

Defense against toxins and pathogens

What is the role of Blood relating to body temperature?

Stabilisation of body temperature

What is Plasma?

Fluid consisting of water, dissolved plasma proteins, solutes

What takes up 92% of Plasma?

Water

What is Hemopoiesis?

Process of producing formed elements by myeloid/lymphoid stem cells

What are the 3 General Characteristics of Blood?

• Temperature

• Viscosity

• pH

37C, high viscosity, slightly alkaline

What percentage of human body weight is blood volume?

7%, 5-6 Litres (Males), 4-5 (Females)

How much of blood volume is Plasma?

50-60%

How much of Plasma is water?

Over 90%

Where are Plasma Proteins made?

Liver

What are Albumins in the Blood Plasma?

Transport substances such as fatty acids, thyroid hormones (60%)

What are Globulins in the Blood Plasma?

Antibodies (immunoglobins) made by plasma cells (35%)

What is Fibrinogen in the Blood Plasma?

Molecules that form clots and produce long, insoluble strands of fibrin (4%)

What is Serum?

Liquid part of blood sample, no cells or clotting factors

How does Hemoglobin relate to the colour of blood?

Red pigment that gives blood its colour

What is the role of Hemoglobin?

Binds and transports oxygen and carbon dioxide

What is Hematocrit?

Percentage of blood volume that consists of erythrocytes

What is the Hematocrit in males?

40-54%

What is the Hematocrit in females?

37-47%

What does PCV stand for?

Packed Cell Volume

Describe the structure of Red Blood Cells

Small and highly speciated discs, thin in middle, thicker at edge

What is the lifespan of Red Blood Cells?

120 days

Why do Red Blood Cells have such a short lifespan?

Lack nuclei, mitochondria, ribosomes so no repair

What are the 3 important effects of Red Blood Cell Shape on Function?

High SA:Vol, Discs form stacks (rouleaux), Discs bend and flex

Why is the high Surface Area to Volume Ratio important for Red Blood Cells?

Quickly absorbs and releases oxygen

What is the importance of discs forming stacks for Red Blood Cells?

Smooth flow through narrow vessels

Why is it important for Red Blood Cells that discs bend and flex?

Bend and flex entering small capillaries

How many Globular Subunits does Hemoglobin have?

4

What is the importance of Hb’s Globular Subunits?

Each with 1 heme molecule, each heme contains an Fe ion

How does Hb transport Carbon Dioxide?

Binds to Carbon Dioxide and carries it to lungs, forms carbaminohemoglobin

How much of circulating Red Blood Cells wear out per day?

1%

Where does Hb Conversion and Recycling happen?

Liver, spleen, bone marrow

Describe Hb Conversion and Recycling?

Macrophages monitor RBCs, engulf RBCs before membranes rupture (hemolyze)

How do Bacterial Infections influence neutrophils?

Bacterial infections increase number of neutrophils

Where are myeloid stem cells located?

Bone marrow

Where are lymphoid stem cells located?

Lymph

How is Plasma different to Serum?

Has proteins which clot blood (clotting factors)

What happens to Red Blood Cells after their lifespan?

Engulfed by macrophages

What is the effect of Bilirubin accumulation in liver?

Yellow skin

What is Hemoglobinuria?

Some Hb released from urinary duct, pink urine

What is Hematuria?

Blood in urine

Why is a decrease in Iron an issue?

Needed in Hb

What is the effect of Bile Duct blockage?

Bilirubin remains in liver

What can cause Bile Duct blockage?

Cancer

What is Pernicious Anemia?

Small RBCs, Vitamin B12 deficiency

What do Phagocytes break Hb into?

Components, Globular Proteins to amino acids

What happens to Hb not phagocytised?

Breaks down and the alpha and beta chains are eliminated in urine

Where does Bilirubin come from?

Excreted by liver

What causes Jaundice?

Bilirubin build up

How does Iron Recycling begin?

Iron removed from heme leaving biliverdin

What is the importance of Iron Recycling in transport?

Transport proteins (transferin)

What is the importance of Iron Recycling in storage?

Storage proteins (ferritin & hemosiderin)

What are Hemocytoblasts?

Stem cells in myeloid tissue divide to produce Myeloids and Lymphoids

What is the role of Myeloid Stem Cells?

Become RBCs/WBCs

What is the role of Lymphoid Stem Cells?

Become Lymphocytes

Stages of Red Blood Cell Maturation

Myeloid stem cell, proerythroblast, erythroblasts, reticulocute, mature RBC

What is required to build Red Blood Cells?

Amino acids, iron, vitamin B12/B6, folic acid

What is EPO?

Erythropoiesis Stimulating Hormone

What is the function of EPO?

Secreted when Oxygen in peripheral tissues is low (hypoxia) due to disease/high altitude

How many blood types are there?

8 - A+, A-, B+, B-, AB+, AB-, O+, O-

What are the 2 main antigens in Blood Typing?

Agglutinogen A and B

Describe the structure of White Blood Cells?

No Hb, but have nuclei

What are the functions of White Blood Cells?

Defend vs pathogens, remove toxins and wastes, attack abnormal cells

How much of the blood are WBCs?

Small numbers in blood - 5-10K per microliter

Importance of Myeloid Stem Cells in WBC production?

Produce all WBCs except lymphocytes

What is Lymphoiesis?

Production of lymphocytes by lymphoid stem cells

What are Neutrophils?

• Pale cytoplasm granules w/ lysosomal enzymes and bactericides

• 50-70% of circulating WBCs

What are the roles of Neutrophils?

• Very active, 1st to attack bacteria

• Engulf and digest pathogens

• Degranulation - removing granules from cytoplasm

• Defensin production

• Forms pus

What is the result of producing Defensin?

Releases prostaglandins and leukortrienes

What is Eosinophilis?

2-4% of circulaitng WBCs, attack large parasites and extrete toxic compounds

What toxic compounds do Eosinophilis excrete?

Nitric oxide, cytotoxic enzymes

What are Eosinophilis also known as?

Acidophilis

What is Basophilis?

<1% of circulating WBCs, accumulate in damaged tissue, release histamine and hepanin

What is the effect of histamine release?

Dilates blood vessels

What is the effect of hepanin?

Prevents blood clotting

What are Monocytes?

2-8% of circulating WBCs, large and spherical

How do Monocytes become Macrophages?

Enter peripheral tissues to become macrophages

Role of Monocytes in engulfing?

Engulf large particles and pathogens

Role of Monocytes during injury?

Secrete substances that attract Immune System cells & fibroblasts to injured area

What are Lymphocytes?

20-40% of WBCs, larger than RBCs, migrate in & out blood

Where are Lymphocytes usually?

Connective tissues and lymphoid organs

What is the role of Lymphocytes when there is an increase in Viral Infection?

Lymphocyte production

What are the classes of Lymphocytes?

T cells, B cells, Natural Killer Cells

What are T Cells?

Cell mediated immunity, attack foreign cells directly

What are B Cells?

Humoral immunity, differentiate into plasma cells, synthesise antibodies

What are Natural Killer (NK) Cells?

Detect and destroy abnormal tissue cells

What are Platelets?

Cell fragments involved in human clotting system

How long do Platelets circulate for?

9-12 days

What removes Platelets?

Spleen

Where does Platelet production occur?

Bone Marrow

What is Thrombocytopenia?

Abnormally low platelet count

What is Thrombocytosis?

Abnormally high platelet count