6.2 The blood system

TOPIC 6 & 11: HUMAN & ANIMAL PHYSIOLOGY

1- THE HEART BEATSRead & Consider 6.2.6-6.2.12

• 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

UnidirectionalValvesOxygenated vs.

Deoxygenated Blood

Action of the Heart

Diastole: the heart muscle is relaxed.

Systole: the heart muscle is contracting.

No Brain RequiredMyogenic: the heart beat is initiated by

the heart muscle itself. It does not require external nerve input.Sino-atrial node (SA node) – pacemakerAtrio-ventricular node (AV node)

Myogenic Contraction

Gardenrain.com

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.

Heartbeat

Autonomic Nervous SystemMedulla 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.

Decibel-design.com

2 - VESSELSRead & Consider 6.2.1-6.2.6

• What do you know?• What questions do you have?

Arteries & Veins

CapillariesCapillaries link

arteries to vein and in turn help to deliver oxygenated blood to body tissues.No muscleNo elastic tissueNo valvesOne cell layer thick

Coronary Heart Disease

Works CitedDelfino, 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.