Chapter 10 – Circulatory System

1. Biology 20 Unit D Chapter 10 – Circulatory System Bill Nye –Heart - https://www.youtube.com/watch?v=bwBM2Pa1LA8 Bill Nye - blood and circ - https://www.youtube.com/watch?v=IloEyuUGIpU Bozeman Science - https://www.youtube.com/watch?v=NJzJKvkWWDc Crash Course – Respiratory and Circulatory https://www.youtube.com/watch?v=9fxm85Fy4sQ

2. Circulation (P310) • This is a TRANSPORT system that allows every cell: • i) uptake of nutrients ( ex. oxygen, glucose) • ii) excretes wastes (ex C02, ammonia) • requires action of: • heart: muscular force to move blood around the body through blood vessels • blood: fluid tissue that carries nutrients, wastes and other molecules • Your circulatory system is composed of 96,000 km of blood vessels!! • Every minute 5 L of blood cycles from the heart to the body and back to the heart.

4. 10.1 Blood Vessels (Pages 312 – 318) i) Arteries • carry blood AWAY from the heart • carry blood with oxygen (red), exception: pulmonary artery • walls are thick, strong, and stretchy • composed of three layers • carry blood at high pressure ii) Arterioles • smaller arteries • Vasoconstriction: • Vasodialation: Major Blood vessels: http://www.nelson.com/ABbio20-30/teacher/protect/media/major_vessels.html

5. iii) Capillaries • smallest vessel in body (single cell layer thick) • branch through tissues • site of fluid and gas exchange ( oxygen, nutrients, carbon dioxide, and wastes) between blood and tissue fluid by diffusion • red blood cells must pass through SINGLE FILE • fragile eg: bruise

6. iv) Veins • carry blood TOWARDS the heart • blood is deoxygenated (blue), exception :pulmonary vein • thin-walled; carry blood under low pressure • contain VALVES which open in one direction only • skeletal muscle contraction aids venous blood flow v) Venules • smaller veins where deoxygenated blood collects from capillaries

7. Summary of blood vessels:

8. Key Terms: • Arteries • Arterioles • Pulse • Autonomic nervous system • Vasoconstriction • Vasodilation • Atherosclerosis • Arteriosclerosis • Aneurysm • Veins • Varicose veins • Venules • Capillaries

9. Tasks to be completed: • Read Pages 310-318 in Textbook • Complete Section 10.1 Questions 1-9 on Page 318 • Complete Fetal Pig Lab Prep Booklet

10. 10.2 – The Heart Pages 319-327

11. Heart Anatomy

14. The Heart… • muscular organ, size of your fist • surrounded by a fluid-filled membrane: pericardium which reduces friction 1. Circulation • PULMONARY CIRCULATION • deoxygenated blood pumped from the right side of the heart to the lungs via the pulmonary arteries • blood picks up oxygen (oxygenated) and travels back to the left side of the heart via the pulmonary veins. • the pulmonary arteries are the only group of arteries that carry deoxygenated blood • the pulmonary veins are the only group of veins that carry oxygenated blood

15. SYSTEMIC CIRCULATION • left side of heart pumps blood to the entire body via the aorta (largest artery) • from the aorta blood is diverted to: a) coronary arteries - serve heart tissue b) upper body arteries c) lower body arteries d) Hepatic/Portal system (digestive) • starts with the intestines and finishes in the liver • two large veins: the superior and inferior vena cava return blood to the right side of the heart

16. 2. Chambers • each side has two hollow (four chambers total), muscular chambers which is separated by a wall called the septum • two thin-walled atria (receives blood) • two thick-walled ventricles (pumps blood out of the heart)

17. 3. Valves • allow blood to flow in one direction only • AV (atrioventricular) valve, separates atria & ventricles • SV (semilunar) valve, separates ventricles and arteries (pulmonary trunk and the aorta) • tiny chords anchor flaps of valves to ventricle walls • Trace the path of blood through the heart starting at the right atrium and finishing with the aorta!

18. Control of the Heartbeat • cardiac muscle is able to initiate its own contraction separate from the central nervous system • SA node (sinoatrial node) initiates and controls the heartbeat, but external stimulation can speed up or slow down the heart. i.e. adrenaline • The SA node is located at the top right side of the right atrium. Electrical impulses are sent through nodal fibers causing the muscle to contract • The electrical impulses are delayed from the top to the bottom of the heart. Why? • When the atria are contracting the ventricles need to be relaxed and vice versa.

21. Electrocardiographs (ECG) • Electrodes are placed on body surface and record electrical impulses • Impulses are displaced on electrocardiogram • Doctors analyze graph for proper heart function

23. Activates sympathetic nerves Signals to S.A Node to increase H.R Stress Activates parasympathetic nerves Signals to S.A Node to decrease H.R Relaxed External Regulation of Heart Rate • The S.A node is regulated externally by the parasympathetic and sympathetic nerves which conduct electrical impulses from the medulla oblongata of the brain

24. 5. Heart (Cardiac) Cycle • the sequence of heart chamber contraction is called the heart cycle • diastole: heart (chamber) relaxation • systole: heart (chamber) contraction 6. Heart Sounds • “lubb-dubb” sound of heart beat • “lubb” caused by closing of both the atrioventricular valves • Heart Sounds Quick time video • “dubb” caused by closing of both the semilunar valves Heart Sounds Quick time video

25. Key Terms for Section 10.2 • Septum • Pulmonary circulatory system • Systemic circulatory system • Atria (atrium) • Ventricles • Atrioventricular (AV) valves • Semilunar valves • Aorta • Coronary arteries • Myogenic muscle • Angioplasty

26. Key Terms Continued… • Sinoatrial (SA) node • Purkinje fibres • Sympathetic nervous system • Parasympathetic nervous system • Systole • Diastole • Stroke • Heart attack • Heart murmur