BLOOD VESSELS
BLOOD VESSELS
 Arteries take blood away from the heart.
BLOOD VESSELS
 Arteries take blood away from the heart.
 Artery walls are thickened with connective tissue to withstand
blood pressure, yet elastic enough to expand and contract to
even out pressure from each heart beat.
BLOOD VESSELS
 Arteries take blood away from the heart.
 Artery walls are thickened with connective tissue to withstand
blood pressure, yet elastic enough to expand and contract to
even out pressure from each heart beat.
 When arteries lose their elasticity ( eg. Because of poor diet,
or from disease) high blood pressure develops, which puts
strain on the heart, af fects kidneys and can even cause
arteries to burst.
 https://www.youtube.com/watch?v=ByB7cK9iTKA
BLOOD VESSELS
 Arteries divide into smaller vessels called arterioles, which
supply blood to capillaries.
BLOOD VESSELS
 Arteries divide into smaller vessels called arterioles, which
supply blood to capillaries.
 Capillaries are the smallest blood vessels; their walls are only
one cell thick, allowing rapid exchange of materials between
the blood and individual cells.
BLOOD VESSELS
 Arteries divide into smaller vessels called arterioles, which
supply blood to capillaries.
 Capillaries are the smallest blood vessels; their walls are only
one cell thick, allowing rapid exchange of materials between
the blood and individual cells.
 Blood enters capillaries under pressure, forcing fluid and
useful materials out of capillaries to surrounding cells.
BLOOD VESSELS
 Arteries divide into smaller vessels called arterioles, which
supply blood to capillaries.
 Capillaries are the smallest blood vessels; their walls are only
one cell thick, allowing rapid exchange of materials between
the blood and individual cells.
 Blood enters capillaries under pressure, forcing fluid and
useful materials out of capillaries to surrounding cells.
 Fluid containing waste products or cell secretions is drawn
into the venule end of a capillary by osmosis and dif fusion.
 https://www.youtube.com/watch?v=VVJJHw_Ocp4
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
 The lumen (in picture) of a vein is wider than that of an artery
– valves are present in veins.
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
 The lumen (in picture) of a vein is wider than that of an artery
– valves are present in veins.
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
 The lumen (in picture) of a vein is wider than that of an artery
– valves are present in veins.
 Blood moves through veins towards the heart by:
- The squeezing of muscles against the walls of veins
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
 The lumen (in picture) of a vein is wider than that of an artery
– valves are present in veins.
 Blood moves through veins towards the heart by:
- The squeezing of muscles against the walls of veins
- Gravity
- Pressure in the chest cavity during inspiration ‘pulling’ blood
into the heart.
VEINS
 The reduction in the volume of blood fluid, and friction
between blood cells and capillary walls, causes blood
pressure to drop, so that blood flowing through veins is of very
low pressure.
 Veins carry blood back to the heart – they have thinner walls
than arteries.
 The lumen (in picture) of a vein is wider than that of an artery
– valves are present in veins.
 Blood moves through veins towards the heart by:
- The squeezing of muscles against the walls of veins
- Gravity
- Pressure in the chest cavity during inspiration ‘pulling’ blood
into the heart.
- Some (very low) blood pressure helping push blood through
the veins.