Cardiovascular System Chapter 12

The big idea Why is the cardiovascular system important? The cardiovascular system pumps blood which carries oxygen and removes CO2 from the tissues of the body.

Parts of the System Heart Blood Vessels Blood

Anatomy of the Heart Located in the Thoracic Cavity The heart is a muscle (cardiac muscle) Main Function: Pump Blood The Human heart has four chambers Left Atrium Right Atrium Left Ventricle Right Ventricle

Anatomy of the Heart Atria – receiving chambers of the heart Left receives blood from the lungs Right receives from the body Ventricles – sending chambers of the heart Left sends blood to the body Right sends blood to the lungs Interventricular septum separates the two

Anatomy of the Heart Operation of Blood Valves Atrioventricular (AV) valves – between the Atrium and ventricle Tricuspid valve – right side Bicuspid valve – left side always open until the ventricles contract Contraction pressure forces them to shut

Anatomy of the Heart Semilunar valves – valve leading out of ventricles Normally closed until ventricle contraction opens it https://www.youtube.com/watch?v=JA0Wb3gc4mE

Anatomy of the Heart Major Blood Vessels of the Heart : Vena Cava – carry deoxygenated blood from body to heart enters right atrium Aorta – delivers oxygenated blood from heart to body exits left ventricle

Anatomy of the Heart Pulmonary Veins – delivers oxygenated blood from lungs to heart Enters left atrium Pulmonary Arteries – carries deoxygenated blood from heart to lungs Exits right ventricle

Physiology of the Heart Heart beats 115,200 times a day How does the heart contract (pump)? Bundles of nerve fibers stimulate the muscle to contract The main bundle is the SA node (this is our natural pacemaker) Electrocardiogram (ECG) – measure the electrical activity of heart beats Ineffective valves can cause a heart murmur.

Anatomy of the Blood Vessels Function: transport blood & contents Types of Blood Vessels: Arteries – transport blood away from heart Veins – transport blood to the heart Capillaries – microscopic vessels where gas exchange occurs

Anatomy of the Blood Vessels Size of vessels (large to small) Arteries  arterioles  capillaries Veins  venules  capillaries Major arteries: Aorta, Pulmonary Artery Major Vein: Vena Cava, Pulmonary Vein

Anatomy of the Blood Vessels

Anatomy of the Blood Vessels

Physiology of the Blood Vessels It only takes one minute for a drop of blood to go from the heart to the foot and back to the heart! Blood moves from areas of high pressure to areas of low pressure Blood pressure – is the force of blood against a blood vessel wall

Physiology of the Blood Vessels Factors that affect blood pressure: (pg 236) Amount of blood leaving the heart Peripheral resistance – friction Size of vessels Length of vessels Obese individuals are prone to high bp For one extra pound of fat, 200 miles of blood vessels develop

Evaluating Circulation Heart Beat Stethoscope Pulse Pulse points: pg. 238 Blood Pressure sphygmomanometer

Anatomy of the Blood Composed of 2 basic components Cells (red, white, platelets) = 45% Plasma (water, amino acids, vitamins, hormones, electrolytes, cellular waste) = 55%

Anatomy of the Blood Erythrocytes (red blood cells) – transport oxygen and carbon dioxide Hemoglobin – protein that binds with gases Iron is an important part Oxyhemoglobin – full of O2 (bright red) Deoxyhemoglobin – not carrying O2 (dark red) Shape: concave discs

Anatomy of the Blood About 5 million per cubic millimeter No nucleus…they must be made in the bone marrow Erythropoetin (EPO) – is a hormone that increases RBC production Anemia – condition where there are too few blood cells

Anatomy of the Blood Blood Facts http://www.bloodcenters.org/blood-donation/facts-about-blood-donation/ Heart Labeling Practice http://sciencelearn.org.nz/Contexts/See-through-Body/Sci-Media/Animation/Label-the-heart

Chapter Review Pg. 252 Study Q’s - # 1, 3, 8, 9, 11 Objective Q’s - # 1-4, 9, 12

Sheep Heart Dissection Part 1 – External anatomy of heart https://www.youtube.com/watch?v=iYKhrjfkMwA Part 2 – Internal anatomy of heart https://www.youtube.com/watch?v=HNxSC244Bpo