Chapter Overview

8.1 The Circulatory System - Introduction & Anatomy

8.2 The Blood & Blood vessels

8.3 The Hear t & Cardiac Cycle 8.4 Heart Diseases

8.1.1 The need for transport

8.1.2 Double Circulation

8.2.1 Components of the Tissue Fluida) Blood Plasmab) Red Blood Cellsc) White Blood Cellsd) Platelets

8.2.2 Exchange of Substances and The Lymphatic System

8.2.3 Haemoglobin

8.2.4 Rejection and ABO Blood Group

8.2.5 Structure-function of blood vessels

8.4.1 Myocardial infarction

8.4.2 Causes of Heart Diseases

8.3.1. Structure and Function of heart

8.3.2 Heart valves, Systole and Diastole

Transport in Mammals

(a) Explain the need for transport system in mammals(b) State the differences between single and double

circulation, and the advantages(c) Identify the main blood vessels to and from the

heart, lungs, liver and kidney.(d) State the functions of blood(e) List the different ABO blood groups and all possible

combinations for the donor and recipient in blood transfusions.

Objectives

Imagine you are an amoeba… (unicellular organism)

Oxygen

FoodCarbon Dioxide

Water

Waste materials

Cell is able to exchange substances DIRECTLY with the environment.

Diffusion is enough

Transport in Humans

Multi-cellular organism

Is diffusion enough?

Do you know how many cells do we have in our body?

How to transport materials into and out of Mr Bean efficiently?

4

Adapted from http://farm1.static.flickr.com/107/291667041_e1e590124a.jpg?v=0

Who will need a transport system?

Unicellular organism (e.g amoeba)

Adapted from http://www.akalaty.com/akalaty/wp-content/uploads/2007/05/extra-big-fat-cartoon.jpg

Multi-cellular organism

(e.g humans)

Cells are too far from external environment. Organism needs transport system to ensure efficient exchange of substances.

Organism does not need transport system. Cell is able to exchange substances directly with the environment.

The Need for Transport

What makes simple diffusion a reliable mechanism in unicellular organisms?

Here are two important factors:

1. LARGE Surface Area to Volume Ratio

2. Maintaining a Steep Diffusion gradient

The Need for Transport

Multicellular organisms thus cannot depend on simple diffusion because they have:

1. SMALL Surface Area to Volume Ratio

2. DIFFICULTY in maintaining a STEEP Diffusion gradient

How could they solve these problems?

The Need for Transport

1. SMALL Surface Area to Volume Ratio Increase surface area by having an internal system

of channels or chambers.

2. DIFFICULTY in maintaining a STEEP Diffusion gradient A diffusion gradient is difficult to maintain if they are

bathed in static body fluid. Solution: Devise a pump to Actively circulate the body

fluid

Human Circulatory System

Transport system in mammals are subdivided into:

Blood system carrying blood

Lymphatic system carrying lymph

Blood Circulatory System

• What does the circulatory system consist of?

• What is the function of the circulatory system?

•How are the heart and blood vessels connected to allow circulation of blood?

Heart, Blood Vessels, Blood

Circulates blood around the body – Transports useful substances such as oxygen and food to all body cells and transports waste products such as carbon dioxide and urea to the sites of disposal.

Circulatory System

Blood Blood Vessels

Heart

12

3 Parts of the circulatory system• Heart

– The muscular pump, that moves the fluid– Causes your pulse

• Blood vessels– The system of channels and tubes that are

connected to all parts of the body

• Blood– The fluid that has the capacity to carry the

metabolites13

Double Circulation

• For every organ, there will be at least one main artery which brings oxygenated blood from heart to the organ and one main vein which brings deoxygenated blood out of the organ to the heart.

*take note of the main blood vessel

• Closed system

Double Circulation

• Blood passes through the heart twice in 1 complete circuit.

• Double circulation Pulmonary circulation Systemic circulation

Human Circulatory System

•Double circulation 1) Pulmonary circulation (low pressure) – circulation of blood from heart to lungs to heart

2) Systemic circulation (high pressure) – circulation of blood around the body except lungs

•One-way flow of blood

Advantages of Double Circulation

• (Pulmonary Circulation) Lower pressure to lungs, blood flows slower, allows sufficient time for gaseous exchange;

• (Systemic Circulation) Higher pressure to body, ensure efficient transportation of useful materials(e.g oxygen) to rest of body cells and allow cells to maintain a high metabolic rate.

Organisation of Blood Vessels

(a) State the functions of blood• red blood cells – haemoglobin and oxygen transport• plasma – transport of blood cells, ions, soluble food

substances, hormones, carbon dioxide, urea, vitamins, plasma proteins

• white blood cells – phagocytosis, antibody formation and tissue rejection

Objectives

Red Blood Cell

White Blood Cell

Platelets

 ‹

22

Composition of blood

Plasma (Fluid)

55%

Blood cells (corpuscles)

44%

Platelets

1%

Red blood cells White blood cells

Blood- A tissue fluid

Composition of blood

Components of Blood

(2%)

1. Plasma – 55% total volume of blood mostly liquid water (~90%) soluble blood proteins (7%) hormones electrolytes nutrients

2. Cellular Component – 45% total volume of blood White blood cells Platelets Red blood cells

Only red blood cells and plasma transport materials!

Functions of Blood1. Transport

a. Oxygenb. Carbon Dioxide (bicarbonate ions) lungsc. Foodd. Hormonese. Nitrogenous waste product kidneys

2. Protectiona. Production of antibodiesb. Phagocytosis of foreign bodiesc. Clotting of blood (prevent loss of blood)

3. Distribute body heat especially from muscles and liver, to maintain uniform body temperature

Transports substances such as:

1) Plasma proteins

(fibrinogen,prothrombin and antibodies).

2) Dissolved mineral salts occurring as ions

(Na+, +K,Ca2+, Cl-, hydrogencarbonates).

3) Food substances (glucose, amino acids, fats,

vitamins)

4) Excretory products (urea, uric acid,creatinine

and CO2 as hydrogencarbonate ions)

5) Hormones (insulin, glucagon)

6) Blood cells (red and white blood cells)

pale yellow liquid

made up of 90% water and a mixture of dissolved substance

Plasma

FunctionStructure TB Pg 140

Plasma

The amount of soluble proteins, mineral salts and glucose in the blood plasma are kept relatively constant

by the HOMEOSTASIS mechanism (Chapter 12)

TB Pg 140

Components of BloodRed Blood Cells (Erythrocytes)

1. Biconcave, circular, flattened discs

Increase surface area to volume ratio Thinner central area facilitates rapid diffusion of oxygen in and out of the cell.

2. No nucleus, DNA or mitochondria

Allows the RBC to carry more Haemoglobin, thus facilitating the binding and transport of more oxygen molecules.

TB PG 141

Components of Blood

Red Blood Cells (Erythrocytes)

3. Small, Flexible and Elastic To squeeze through narrow blood capillaries more easily

4. Contains haemoglobin (Hb) Allows the reversible binding of oxygen for oxygen transport.

TB PG 141

White blood cell

Defenders of the body:WHITE BLOOD CELL

What are the similarities between a COUNTER-TERRORIST unit and a WBC?

31

White Blood cell

32

• colourless (no haemoglobin)

• larger than red blood cells

• ratio of red blood cells: white blood cells = about 700:1

• irregular in shape

• has nucleus

• can move and change shape (able to squeeze through walls of capillaries)

White Blood Cells (Leucocytes)

Two groups of leucocytes:1. Lymphocytes

Formed in bone marrows and mature in lymph node Typically round with rounded nucleus Relatively small amount of non granular cytoplasm Produces antibodies that fight against pathogens

2. Phagocytes Many types, shapes and sizes Granular with lobed nucleus Ingests foreign bodies by phagocytosis

TB PG 142)

Test Yourself! (page 143)

(a) Red blood cells contain a red pigment and have a circular, biconcave shape.

White blood cells are round in shape. Platelets are small fragments with irregular shapes.

(b)The diameter of the red blood cells is decreased so that they can pass easily through the lumen of capillaries; the red blood cells increase their surface area to speed of absorption or release of oxygen; the bell shape slows down the rate of blood flow, giving more time for gaseous exchange.

(c) The cells of the body constantly require oxygen to provide energy by tissue respiration, whereas the white blood cells are required only at certain times.

Platelets (Thrombocytes)

Platelets (Thrombocytes)

1. Not true cells; cytoplasmic fragments2. Play Critical role in the clotting of blood

(to be discussed later)

Functions of Blood

1. Transporta. Oxygenb. Carbon Dioxidec. Digested Food from blood capillaries

in small intestined. Hormonese. Waste

2. Protectiona. Production of antibodiesb. Phagocytosis of foreign bodiesc. Clotting of blood (prevent loss of blood)

3. Distribute body heat especially from muscles and liver, to maintain uniform body temperature

Carried by plasma

How the Red blood cells transport O2

Functions of Blood

1. Transporta. Oxygen By Haemoglobin in RBC

Haemoglobin• A protein complex that contains 4 iron atoms• Gives blood its red colour• Able to bind to oxygen molecules• In the unbound state, haemoglobin is a

deep purplish red.• When oxygen is bonded, haemoglobin turns

into a bright red oxyhaemoglobin.

Fe

Fe

Fe Fe

Fe

Fe

Fe Fe

Functions of Blood

1. Transporta. Oxygen – The Role of Haemoglobin

Haemoglobin• Unbound state haemoglobin has

HIGH AFFINITY for oxygen.

• Binds to oxygen easily.

• Reversible process. How is it reversible?

Functions of Blood

1. Transporta. Oxygen – The Role of Haemoglobin

Hb(O2)4 (oxyhaemoglobin)

high oxygen concentration (lungs)

low oxygen concentration ( in body

tissues)

Hb + 4O2

(haemoglobin)Purplish red

Bright red

Fe

Fe

Fe Fe

O2

O2

O2

O2

Functions of Blood

As blood passes through oxygen-poor tissues, oxyhaemoglobin releases its oxygen. Oxygen then diffuses in solution into tissue cells.

Body TissuesRed Blood Cell

42

The oxygen shuttle

Adapted from http://www.3dscience.com/img/Products/Images/clip_art/respiratory_alveoli_web.jpg

Adapted fromhttp://www1.bellevuepublicschools.org/curriculum/k6web/fifthgrade/bodysys/alveoli2.jpg

Alveoli in lungsPulmonary artery Pulmonary vein

Deoxygenated blood is brought back to the lungs through pulmonary arteries.Oxygenated blood is brought out of the lungs through pulmonary veins.

Transport function

Adapted from http://www.3dscience.com/img/Products/Images/clip_art/respiratory_alveoli_web.jpg

Adapted fromhttp://www1.bellevuepublicschools.org/curriculum/k6web/fifthgrade/bodysys/alveoli2.jpg

Alveoli in lungsPulmonary artery Pulmonary vein

Oxygen diffuses from the alveoli (higher concentration of oxygen) to blood capillaries (lower concentration of oxygen), down a concentration gradient.

Carbon dioxide diffuses from the blood capillaries (higher concentration of oxygen) to alveoli (lower concentration of oxygen).

O2

O2

O2

O2

O2

O2

Transport function

Adapted from http://www.3dscience.com/img/Products/Images/clip_art/respiratory_alveoli_web.jpg

Adapted fromhttp://www1.bellevuepublicschools.org/curriculum/k6web/fifthgrade/bodysys/alveoli2.jpg

Alveoli in lungsPulmonary artery Pulmonary vein

Oxygen diffuses from the alveoli (higher concentration of oxygen) to blood capillaries (lower concentration of oxygen), down a concentration gradient.

Carbon dioxide diffuses from the blood capillaries (higher concentration of oxygen) to alveoli (lower concentration of oxygen).

CO2

CO2

CO2

CO2

CO2

CO2

Transport function

Carbon Monoxide

=

Carboxyhaemoglobin formation

Carbon Monoxide Poisoning

46

• Haemoglobin combines even more readily with carbon monoxide than with oxygen to form a bright pink compound called carboxyhaemoglobin.

• Unlike oxyhaemoglobin, carboxyhaemoglobin does not readily give up its carbon monoxide, so the haemoglobin becomes useless.

• This is why people can be poisoned by the fumes of gas or car exhausts in a confined space.

Carbon Monoxide Poisoning

47

TB Pg 147

• by placing face masks on the patients and supplying them with air containing a much higher proportion of oxygen than usual.

Carbon Monoxide Poisoning

48

Transport functionHow is a molecule of oxygen being

transported from lungs to the liver cell?

As RBC moves through the capillaries in the lungs, oxygen diffuses from the alveoli (higher concentration) into RBC (lower concentration).

Haemoglobin in RBC binds with oxygen to form oxyhaemoglobin.

Blood transports oxyhaemoglobin to all tissues in the body.

Oxyhaemoglobin releases its oxygen to tissues containing very little oxygen by diffusion.

Rearrange!

1 2

3

4

Thinking time…

• How do humans adapt to living at high altitude?

• What makes their cheeks so red?

• At high altitudes, oxygen is low. to compensate for the low concentration of oxygen body produces more red blood cells

(acclimatisation) rosy cheeks.

• Increasing the proportion of RBC increases haemoglobin content

more oxygen can be transported to tissue cells per unit time.

• For the same reason, long distance runners often train at high altitudes before a big race hence when they run at lower altitudes, body can carry oxygen more efficiently, run longer.

Functions of Blood

1. Transportb. Carbon dioxide

CO2 diffuse into blood plasma

Converted to HCO3- ions and carried in

blood plasma

As blood passes

through lungs…

HCO3- ions converted

back to CO2

Conc. of CO2 higher in plasma than lungs

Diffusion from

plasma to lungs

HCO 3-CO

2

Functions of Blood

1. Transportc. Foodd. Hormonese. Waste

Examples• Glucose• Amino Acids• Vitamins

Chemical messengers that control many metabolic processes.

Examples• Insulin• Glucagon• Adrenalin

Excretory products delivered to the kidneys for removal.

Examples• Urea• Uric Acid• Creatinine

Functions of Blood

1. Transporta. Oxygenb. Carbon Dioxidec. Foodd. Hormonese. Waste

2. Protectiona. Production of antibodiesb. Phagocytosis of foreign bodiesc. Clotting of blood (reduce loss of blood)

3. Distribute body heat especiallly from liver and muscles

2. Protectiona. Production of antibodies

So we have seen how blood transports metabolic substances and the

important role played by haemoglobin….

Next, we shall look at the protective functions of blood.

Protective functionPhagocytosis Antibody productionBlood Clotting/Coagulation

By platelets By phagocytes By lymphocytes

Protective functionBlood Clotting

2) Damaged tissues and blood platelets release thrombokinase (enzyme).

4) In the presence of calcium ions, thrombokinase catalyses conversion of inactive prothrombin to active thrombin (enzyme).

3) Thrombokinase neutralises action of heparin (anti-clotting substance in blood).

5) Thrombin catalyses conversion of soluble fibrinogen to insoluble fibrin threads.6) Insoluble fibrin threads entangle blood cells. A clot and scab is formed. A yellow-ish liquid serum is left behind

1) Platelets adhere to the cut edges. Platelets release chemicals to attract more platelets. Formation of platelet plug prevents external bleeding.

When blood vessels are damaged,

Function of Blood Clotting• Clotting seals wound, preventing excessive loss of

blood• Clotting of blood by platelets prevent further

entry of bacteria/ foreign particles reduce infection by pathogens

What if some microbes get into the wound?

Protective functionPhagocytosis

• Phagocyte engulfs foreign particle.

• Destroy pathogens by phagocytosis and ingest foreign particles like bacteria that gain entry into blood

• Phagocyte flows over to the foreign particle.

Adapted from http://www.cutiegadget.com/pict/pacman-plush.jpg

Protective functionAntibody production

• This stimulate Lymphocyte releases antibodies.• Antibodies can - rupture bacteria - agglutinate bacteria such that they will be easily digested by phagocytes

- neutralise harmful products (e.g toxins) produced by bacteria/foreign particle.

- prevent viruses from attaching to host cells by attaching to them

• Disease causing micro-organisms in blood stream.

• Antibodies are soluble proteins…

• Mostly produced by lymphocytes.

• Capable of recognizing foreign objects…

• Then binds to them…

• Foreign objects with antibodies bounded to them are

destined for destruction by immune system.

Functions of Blood

2. Protectiona. Production of antibodies

Age Vaccine

At birth BCG (for tuberculosis)Hepatitis B - 1st dose

2 month *Hexa (Six-in-One)

4 months ** DTaP/ IPV/ Hib

6 months Hexa (Six-in-One)

12 months Hepatitis B Booster for children of Hepatitis B carrier mothers only

15 months MMR (Measles/Mumps/Rubella)

18 months DTaP/ IPV/ Hib - 1st booster

6 yearsDT 2nd boosterOral Sabin - 2nd booster (oral polio vaccine)

12 yearsDT 3rd boosterOral Sabin - 3rd boosterMMR - 2nd dose

*  Hexa (Six-in-One) includes   Diphtheria/Tetanus/Pertussis (DTaP)   Haemophilus Influenza type B (Hib)   Inactivated Polio (IPV)   Hepatitis B

** Diphtheria/Pertussis/Tetanus (DTaP), Haemophilus Influenzae type B (Hib) & Polio (IPV)

Vaccination: Injection of dead foreign bodies into humans to stimulate lymphocytes into secreting antibodies

Adapted from http://1.bp.blogspot.com/_lm2JI7sGwYI/SZUGTvIT7RI/AAAAAAAAEkQ/14mCG1Y2RX0/s400/vaccination(5).jpg

Amou

nt o

f anti

bodi

es in

blo

od2nd exposure to the

same foreign bodies

1st exposure to foreign bodies

Graph (1st exposure to foreign bodies): Lymphocytes respond to foreign bodies by producing antibodies.

Graph (2nd exposure to foreign bodies): - More antibodies - Response is faster

Protective functionPhagocytosis Antibody productionBlood Clotting

What will happen when tissue or organ transplant occur?

Organ transplant or tissue rejection

In 2002, Ms De Cruz became the first person in Singapore to receive an organ transplant from an unrelated living donor."Taking medication every day has become ordinary...The only thing I'm fearful about is becoming immune to the anti-rejection drugs I'm on and the possibility of renal failure."

Structure Function

Red Blood Cells (Erythrocytes)

• Circular, flattened, biconcave shape

• No nucleus• Contain haemoglobin• Elastic.Able to turn bell

shape

Transport oxygen from lungs to cells around body

Plasma• Pale yellowish liquid• Contains 90% water

Transports substances such as soluble proteins (e.g. fibrinogen, prothrombin, antibodies), dissolved mineral salts (e.g. calcium), food (e.g. glucose, amino acids), excretory products (e.g. urea, carbon dioxide), hormones (e.g. insulin) around body

White Blood Cells

(Leucocytes)

• Irregular in shape• Presence of nucleus• Colourless.

No haemoglobin• Elastic.

Defense body against diseases

Platelets (Thrombocytes)

Membrane-bound fragments of cytoplasm (not true cells)

Blood clotting

Transport function

Protective function

Test Yourself! (page 151)1(a) To produce antibodies against disease-causing

microorganisms.(b) To ingest and destroy foreign particles like bacteria. (c) To carry oxygen to all parts of the body.(d) To bring about blood clotting when tissue is damaged.2 Any organ from another person may be treated as a foreign body by the recipient’s immune system. The recipient’s lymphocytes may respond by producing antibodies to destroy the transplanted organ.3 By matching the tissue of the donor and recipient as closely as possible, e.g. using tissue donated from a relative, or by using immuno-suppressive drugs.4 Blood may be infected with disease-causing microorganisms such as bacteria. The patient’s body produces more white blood cells to combat the bacteria e.g. more phagocytes to ingest bacteria and more lymphocytes to produce antibodies.