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Unformatted text preview: ure of the blood being
pumped from the heart. Note: The elasticity also
helps to even out the surges that occur with each
contraction of the heart. This keeps the blood
moving forward in a continuous flow.
(b) Blood pressure is low within the arterioles. 3. 4. (c) Endothelium
(d) Blood (or lumen) The smooth muscle around arteries helps to regulate
blood flow and pressure. By contracting or relaxing
it alters the diameter of the artery and adjusts the
volume of blood as required.
(a) The diameter of the artery increases.
(b) The blood pressure decreases. Biozone International 2009 Photocopying Prohibited Anatomy and Physiology 1. Humoral. Type 1 Diabetes Mellitus (page 102)
1. Veins (page 108) 18
Blood (page 111) Anatomy and Physiology 1. Answers given may provide more detail than required.
(b) Protection against disease:
Blood component: White blood cells
Mode of action: Engulf bacteria, mediate immune
reactions, and allergic and inflammatory
(c) Communication between cells, tissues and organs:
Blood component: Hormones
Mode of action: Specific chemicals which are
carried in the blood to target tissues, where they
interact with specific receptors and bring about an
(d) Oxygen transport:
Blood component: Hemoglobin molecule of
Mode of action: Binds oxygen at the lungs and
releases it at the tissues.
(e) Carbon dioxide transport:
Blood components: Mainly plasma (most carbon
dioxide is carried as bicarbonate in the plasma,
a small amount is dissolved in the plasma). Red
blood cells (a small amount (10-20%) of carbon
dioxide is carried bound to hemoglobin).
Mode of action: Diffuses between tissues,
plasma, and lungs according to concentration
(f) Buffer against pH changes:
Blood components: Hemoglobin molecule of
erythrocytes. Plasma bicarbonate and proteins.
Mode of action: Free hydrogen ions are picked
up and carried by the hemoglobin molecule
(removed from solution). Plasma bicarbonate
can form either carbonic acid by picking up a
hydrogen ion (H...
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This document was uploaded on 01/28/2014.
- Winter '13