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Higher Human Biology

Higher Human Biology. Unit 2 Physiology & Health. KEY AREA 5: Structure and Function of Arteries, Capillaries and Veins. Higher Human Biology. We are going to build on the knowledge and skills that you developed during N5 and will learn about the following Physiology & Health key areas : -

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Higher Human Biology

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  1. Higher Human Biology Unit 2 Physiology & Health KEY AREA 5: Structure and Function of Arteries, Capillaries and Veins

  2. Higher Human Biology We are going to build on the knowledge and skills that you developed during N5 and will learn about the following Physiology & Health key areas : - Key Area 1 – Reproductive Organs Key Area 2 –Hormonal Control of Reproduction Key Area 3 – Biology of Controlling Fertility Key Area 4 – Ante- and Postnatal Screening Key Area 5 – Structure and Function of Arteries, Capillaries and Veins Key Area 6 – Structure and Function of the heart Key Area 7 – Pathology of Cardiovascular Disease (CVD) Key Area 8 – Blood Glucose Levels and Obesity

  3. Physiology & Health KEY AREA 5 – Structure and Function of Arteries, Capillaries and Veins • Structure and function of arteries, capillaries and veins • Exchange of materials between tissue fluid and cells

  4. N5 Revision - Role of Blood Vessels The three types of blood vessel are Arteries, Capillaries & Veins Arteries divide up into capillaries, then capillaries join up to make Veins

  5. N5 Revision - Arteries, Capillaries & Veins Thin walled (only 1 cell thick) Thick muscular wall Valves to stop blood flowing backwards Capillaries • thin walled to allow exchange of gas, food and wastes • Capillaries form networks through organs and tissues and have a large surface area • Oxygen leaves capillaries and enters tissues/cells • Carbon Dioxide leaves tissues/cells and enters capillaries Veins • Veins thin muscular walls and a wide channel and carry blood under low pressure TO the heart • Veins contain valves to prevent blood flowing backwards • Veins carry Carbon Dioxide and Wastes Arteries thick muscular walls a narrow channel carry blood under high pressure AWAY from the heart a pulse indicates that blood is flowing through an artery Arteries carry Oxygen and nutrients

  6. Physiology & Health Learning Intentions KEY AREA 5 – Structure and Function of Arteries, Capillaries and Veins • Structure and function of arteries, capillaries and veins • Exchange of materials between tissue fluid and cells

  7. 5a) Arteries, Capillaries & Veins

  8. 5c) Arteries, Capillaries & Veins Capillary

  9. 5d) Vasoconstriction and Vasodilation • The smooth muscular middle layer of arterioles can contract (vasoconstriction) • e.g. during a football match, arterioles undergo vasodilation at muscles to increase the flow of blood to working muscles • The smooth muscular middle layer of arterioles can relax (vasodilation) to control blood flow • e.g. during a football match, arterioles in the small intestine undergo vasoconstriction to reduce blood flow to these regions

  10. 5e) Exchange of materials – Blood Plasma Blood consists of red blood cells, white blood cells, platelets and plasma Plasma is a watery yellow fluid that contains all the blood cells and glucose, amino acids, carbon dioxide, plasma proteins and ions

  11. 5f) Exchange of materials – Tissue Fluid Blood arriving at the arteriole side of a capillary bed is at a higher pressure than the blood in the capillaries, so blood is forced into these narrow capillaries As blood is forced into the narrow capillaries, it undergoes pressure filtration and much of the plasma is squeezed out through the thin walls. The plasma is now part of the tissue fluid (the fluid surrounding cells) Tissue fluid differs from blood plasma as it contains no protein because the protein molecules are too big to pass through the capillary walls Tissue Fluid

  12. 5g) Exchange of materials – Tissue Fluid continued Tissue fluid supplies cells with glucose, oxygen and other substances Carbon Dioxide and other metabolic wastes diffuse out of the cells and into the tissue fluid to be excreted Most of the tissue fluid returns to the blood in the capillaries at the venule side of the capillary bed Excess tissue fluid is absorbed by thin-walled lymphatic vessels, and the fluid is now called lymph. The lymphatic system returns lymph to the circulatory system (bloodstream)

  13. Physiology & Health Questions KEY AREA 5 – Structure & Function of arteries, capillaries and veins • Testing Your Knowledge 1 Page 163 Q’s 1-4 2. Quick Quiz

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