Topic 6 & 11: Human Health & physiology



6.2 The blood system


Read & Consider 6.2.6-6.2.12

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What do you know?

What questions do you have?

Label a diagram of the heart and indicate the flow of blood with arrows.

Blood Flow

 Unidirectional  Valves  Oxygenated vs. Deoxygenated Blood

Action of the Heart

Diastole: the heart muscle is relaxed.

Systole: the heart muscle is contracting.

No Brain Required

Myogenic: the heart beat is initiated by the heart muscle itself. It does not require external nerve input.

Sino-atrial node (SA node) – pacemaker

Atrio-ventricular node (AV node)

Myogenic Contraction  SA node – generate an impulse that spread across both atria causing a simultaneous contraction. ≈ 70 bpm  AV node – picks up the SA signal which travels to the apex and contracts the ventricles from the bottom up.


Autonomic Nervous System  Medulla Oblongata  Cardio-acceleratory center – linked to the SA node  increase cardiac output.

 Cardio-inhibitory center – linked to the SA node, AV node and bundle of His  decrease cardiac output.

Epinephrine (adrenaline) A hormone that travels through the transport system to the SA node. Epinephrine increases the rate which the SA node resets, therefore increasing heart rate.


Read & Consider 6.2.1-6.2.6

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What do you know?

What questions do you have?

Arteries & Veins

Capillaries  Capillaries link arteries to vein and in turn help to deliver oxygenated blood to body tissues.

 No muscle  No elastic tissue  No valves  One cell layer thick

Coronary Heart Disease

Works Cited  Delfino, Mona. "Sacred Language of the Human Body - Waking Times « Waking Times." Waking Times. N.p., 14 Jan. 2014. Web. 11 Aug. 2014.

 Kelly, Miles. "HUMAN BLOOD VESSELS ILLUSTRATION." HUMAN BLOOD VESSELS- ILLUSTRATION. Foto-Libra, 27 July 2005. Web. 11 Aug. 2014.

 Walpole, Benda. Biology for the IB Diploma. Second ed. United Kingdom: Cambridge UP, 2014. Print.

 "William Harvey." William Harvey. Library of Congress, n.d. Web. 11 Aug. 2014.