6.2 The blood system

Read & 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
 Unidirectional
 Valves
 Oxygenated vs.
Deoxygenated
Blood

 Diastole: the heart muscle is relaxed.

 Systole: the heart muscle is contracting.

 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.
Heartbeat
Gardenrain.com

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.
Decibel-design.com

Read & Consider 6.2.1-6.2.6
• What do you know?
• What questions do you have?

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

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.