CHAPTER 2 BLOOD CIRCULATION AND TRANSPORT

2.1 The Transport System in Human Being

Internal transport system is needed to deliver useful materials to body cells and remove waste materials

Internal transport system Circulatory system Human circulatory system Double circulatory

system Blood must flow through heart twice Pulmonary circulation

Transport blood between heart and lungs Systematic circulation

Transport blood between the heart and all other parts of body

Characteristics of circulatory system• Circulating fluid

Blood Transports useful and waste materials

Pumping device Heart Move through body by muscular contractions of heart

Blood vessels 3 main types of blood vessels: arteries, veins and capillaries

Valves Present in some blood vessels Prevent backflow Ensure blood flows in 1 direction only

Structure of human heart

Bicuspid valve / mitral valve

Septum

From head and body

To head and body

From lungs

From trunk and legs

To lungs

Blood Vessels and Their Functions 3 types of blood vessels:

Arteries Veins Capillaries

Human circulatory system is called a closed system

ComparisonsCharacteristics

Artery Vein Capillary

Cross section

Size of lumen Small Big Small

Thickness of wall

Thick, muscular and elastic walls

thinner, muscular and less elastic

Wall only one cell thick

Valves Absent Present Absent

Blood flow Fast and under very high pressure

Slow and under low pressure

Slow and under high pressure

Characteristics

Artery Vein Capillary

Colour of blood inside

Bright red, contains oxygenated blood (except pulmonary artery)

Dark red, contains deoxygenated blood

Bright red, contains oxygenated blood

Function Carries blood away from heart

Carries blood to heart

• Connects arteries and veins

• Allows exchange of substances between blood and body cells

Path of Blood Flow

Pulmonary artery

Pulmonary vein

Aorta

Vena cava

Maintaining a healthy heart

Factors that increase risk of getting heart disease: Heredity Cholesterol and obesity Lack of exercise Smoking Stress Alcohol

Human Blood

Blood

Plasma Blood Cells Blood Fragments

Red Blood Cells

White Blood Cells

Platelets

Plasma makes up 55% of blood by volume The other 45% consists of red blood cells, white

blood cells and platelets

Plasma

Yellow liquid in blood 90% of plasma is water 10% of plasma include:

Nutrients: glucose, amino acids and vitamins

Proteins: antibodies, hormones, enzymes, albumins and fibrinogen

Inorganic ions: sodium, calcium, chlorides and phosphates

Main functions of plasma: To transport nutrients to tissues To remove waste products from tissues To distribute hormones, enzymes,

antibodies and other proteins To distribute heat energy from liver and

muscles to all other parts of body

Red Blood Cells (erythrocytes)

Biconcave, disc shaped cells without nucleus

Transport oxygen from the lungs to all parts of body

Contain a red pigment called haemoglobin which combines with oxygen molecules to form oxyhaemoglobin

Carry carbon dioxide from body cells to lungs

RBC are produced in bone marrow Lifespan: 120 days When RBC are worn out, they are

destroyed in liver and spleen

White Blood Cells (leucocytes)

WBC are much larger than RBC and they each have a nucleus

Usually irregular in shape, colourless and do not contain haemoglobin

Produced from bone marrow cells Lifespan of WBC depends on type of

WBC. It varies from a few hours to a few months

Play a vital role in body’s defense against diseases Produce antibodies

WBC can squeeze through walls of blood capillaries into the space among the cells to destroy the bacteria

Platelets (thrombocytes) Play an important role in blood clotting

Blood groups

ABO system classifies the human blood into 4 groups called A, B, AB and O.

During blood transfusion, donor’s blood must be compatible with the recipient’s blood

When an incompatible type of blood is transfused, RBC of donated blood will agglutinate and cause fatal blockages in recipient’s blood vessels

O A B AB

O

A

B

AB

Donor’s blood

Reci

pie

nt’

s blo

od

Compatible

Incompatible

Blood group O can safely donate blood, in small quantities, to anyone. People with group O are called universal donors

Blood group AB can safely receive blood from anyone. Group AB people are called universal recipients

Transport system in Plants

Non woody plants depend on the water stored in the cells of the stem for support

Wilting occurs in non woody plants when water loss through aerial parts of plant exceeds water absorption by roots

Cells in plants lose their turgidity (stiffness) and the plant droops

Wilting

Transport Tissues in Plants Transport system in plants is made up of

Xylem tissues Phloem tissues

They are found in roots, stems and leaves

Cross section of root

Cross section of stem

Upper epidermis

Lower epidermis

Cross section of leaf

Xylem tissues

Made up of xylem vessels Form woody tissues of plants and give

support Transport water and dissolved minerals

from roots, up the stems and to the leaves

Phloem tissues Transport food substances from leaves

to the stems and roots Xylem and phloem tissues form vascular

bundles