bfd blood vessels session 3
Post on 03-Jun-2015
942 Views
Preview:
TRANSCRIPT
The Structure and Function of Blood Vessels
Session 3
Lesson Re-cap
Aims
• To describe the structure and function of blood vessels
Objectives
• Learners will be able to explain the role of blood, veins, capillaries, arteries and blood vessels
Blood Contains..• Plasma: a watery liquid which contains
calcium, salts and carbon dioxide.
• Red blood cells: carry oxygen from the lungs to our body cells
• White blood cells: are more plentiful than the red cells. Role is to fight infection and disease
• Platelets: produce clots when blood is damaged
Types of Blood Vessels• Arteries: are thick and elastic in texture.
Carry blood AWAY from the heart.• Veins: these are two layers thick. Carry
blood BACK to the heart.• Capillaries: narrow and thin. Connect
arteries and veins.• Arterioles: smallest vessels in body.
Direct blood from arteries to capillary network.
• Venules: direct blood from capillary network to the veins.
Arteries• Muscle action pushes the blood through
the arteries to relevant stops.• Carry blood AWAY from the heart• Arteries carry bright red blood! The colour
comes from the OXYGEN that it carries.
Veins• Transport blood BACK to the heart from
Upper and Lower sections of body• Receive blood from the capillaries after the
exchange of oxygen and carbon dioxide has taken place
Capillaries• Extremely small vessels • Transport blood from the arteries to the
veins • Responsible for the exchange of oxygen &
carbon dioxide between blood
Arterioles• Are like small arteries • Branch out from arteries and lead to the
capillary bed
Venules• Allows deoxygenated blood to return from
capillaries to veins• Quite simple things, with thinner and less-
developed walls
Blood flow and body temperatureThe circulatory system plays an important role in regulating body temperature.
If the body gets too hot, capillaries near the surface of the skin widen. Blood is diverted to the skin where the heat can easily radiate away. This is called vasodilation.
Water from the blood is excreted as sweat to cool the body.
CapillariesSweat gland
Thermoregulation
Blood flow and body temperature
If the body gets too cold, capillaries near the surface of the skin get narrower. Blood is diverted away from the skin to limit heat loss. This is called vasoconstriction.
Sweating stops.
CapillariesSweat gland
Blood vessels
Summary..
• Types of Blood Vessels????
• Role of Blood Vessels…
Any questions..
top related