chapter 2 blood circulation & transport
TRANSCRIPT
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