Blood Vessels Chapter 10 Section 10.1

Arteries and Arterioles blood vessels that carry blood away from the heart Arterioles smaller arteries that carry blood into capillaries

Capillaries Capillaries blood vessels composed of a single layer of cells connect arterioles and venules site of fluid and gas exchange between the blood and the body cells easily destroyed due to their thin structure when they burst bruising occurs

Veins and Venules Veins Venules blood vessels that carry blood toward the heart Venules smaller veins that carry the blood between the capillaries and the veins

Arteries and Veins

Potential Blood Vessel Problems Atherosclerosis A degeneration of blood vessels caused by the accumulation of fat deposits in the inner wall Fat Deposits

Potential Blood Vessel Problems Cont’d Aneurysm a bulge in the weakened wall of a blood vessel, usually an artery can burst and cause severe problems bursting of an aneurysm in the brain can lead to a stroke

Potential Blood Vessel Problems Cont’d Varicose Veins pooling of blood in the veins caused by weakened valves that prevent the back flow of blood against gravity

The Heart Chapter 10 Section 10.2

Introductory Video Http://kidshealth.org/PageManager.jsp?lic=1&article_set=59298&_id=20607

Main Components of the Circulatory System Blood material to be transported Blood Vessels ‘highways’ that transport the blood Heart pumps blood through vessels

The Heart Size: 1 fist Slightly left of the middle of chest Pumps oxygen rich blood to the body Pumps oxygen poor blood to the lungs

The Heart Walls of the heart are made up of CARDIAC MUSCLE. This cardiac muscle contracts rhythmically and involuntarily to pump blood around our body.

Red vs. Blue Red = oxygenated blood Blood just LEAVING lungs, full of oxygen to bring to cells. Blue = deoxygenated blood Blood just about to ENTER the lungs again, full of carbon dioxide ready to be exhaled. NOT ACTUALLY BLUE

2 Circulatory Systems There are essentially two separate circulatory systems within our body. 1. Pulmonary Circulatory System – carries blood to and from the lungs 2. Systemic Circulatory System – carries blood to and from the body

Heart Con’t Our heart has 4 chambers. Atria = top 2 chambers of heart RECEIVE blood from lungs or body Ventricles = bottom 2 chambers PUMP blood to lungs or body Septum = wall in heart that separates the ventricles Thick & muscular

Vena Cavae Large blood vessels that open into the right atrium Superior Vena Cava collects oxygen-poor blood from upper body Inferior Vena Cava collects oxygen-poor blood from lower body

Pulmonary Arteries Arteries that open up into the right ventricle Sends oxygen-poor blood to lungs to be oxygenated ONLY artery in body that contains oxygen-poor blood

Pulmonary Veins Sends oxygen-rich blood from the lungs back to the heart and into the LEFT atrium ONLY veins in body that contain oxygen-rich blood

Aorta Connected to the LEFT ventricle Largest vessel in body Sends oxygen-rich blood to entire body

Heart Valves There are 4 valves that make blood flow in right direction. Atrioventricular Valves 2 of them Separates atria from ventricles Right side: tricuspid (made from 3 flaps) Left side: bicuspid (made from 2 flaps) AKA mitral valve

Heart Valves Semilunar valves Name because of their half moon shape Separates ventricles from blood vessels where they will be eventually pumping blood

Setting the Heart’s Tempo The heart contains specialized muscle called myogenic muscle that contracts without external nerve stimulation. The tempo or beat is set by the sinoatrial (SA) node. The SA node is a small mass of tissue in the right atrium that originates the nerve impulses stimulating a heart beat.

The impulses are sent to a second node, the artioventricular (AV) node. The AV node passes nerve impulses to the ventricles via two large fibres called the Purkinje fibres. Once the nerve impulses reach the ventricles, the ventricles contract and blood is pumped.

Nervous System Input The heart rate can also be influenced by external nerves impulses from the brain in specific situations. The sympathetic nervous system – is a system that prepares your body for stress by increasing your heart rate. Nerve impulses are sent to the SA node The parasympathetic nervous system – is a system that returns the body to normal following a stressful situation by decreasing your heart rate.

Heart Sounds The familiar heart sounds are caused by the closing of the heart valves. The valves are closed when the heart is at rest or relaxating and the atria fill with blood. This time period is known as diastole. The valves are open when the heart is contracting and pushing blood out of the heart. This period is known as systole.

Heart Sounds Cont’d The first beat is the closing of the AV valves. The second beat is the closing of the semilunar valves.

Closure http://www.smm.org/heart/heart/in-out.htm