Circulatory System PDF

# Circulatory System ## Chapter 3.4 The circulatory system provides the **force** and **channels** for distribution of blood which carries food and oxygen to cells and removes wastes. - The circulatory system is organized into 3 primary cycles. - **Coronary system:** within the heart - *...

# Circulatory System ## Chapter 3.4 The circulatory system provides the **force** and **channels** for distribution of blood which carries food and oxygen to cells and removes wastes. - The circulatory system is organized into 3 primary cycles. - **Coronary system:** within the heart - **Pulmonary system:** lungs - **Systemic system:** body ## Circulation ### "The Double Pump" - Blood passes through the heart **twice** each time it completes a circuit. - The right side of the heart receives **deoxygenated** blood from body tissues and pumps it to the **lungs**. - The left side of the heart receives **oxygenated** blood from the lungs and pumps it to all **body tissues**. ## Human Circulatory System - It is a closed system of circulation in which blood is always enclosed in **tubular blood vessels**. - Blood does not come in **direct contact** with body tissue cells. - Body cells must come in close contact with blood to **exchange** materials, therefore, blood vessels are found in almost every part of the body. - The human circulatory system is made up of the **blood vessels**, the **blood**, and the **heart**. ## Blood Vessels ### 1. Arteries - **Thick-walled** tubes composed of elastic muscle tissue. - Can expand in response to pressure changes that result from the pumping action of the heart. - Carries blood **away from the heart**. - Arteries branch off into smaller vessels called **arterioles**. - **Aorta:** principle artery protruding from the heart. ### 2. Veins - **Thin-walled** tubes. - Contains **valves** (think: one-way doors) to prevent backflow of blood due to low pressure in veins. - Carries blood **back to the heart** from **body tissues**. - Small veins are called **venules**. - **Vena Cava:** principle vein going into the heart. ### 3. Capillaries - **Fine network** of tubes surrounding body tissues. - Composed of thin walls only **one cell** layer thick to allow for diffusion of materials quickly across the membrane. - **Oxygen** and **nutrients** move from the capillaries into the **body cells**. - **Carbon Dioxide** and other waste products move from the **body cells** into the capillaries. ## Blood - A 70 kg person has ~ 5L of blood. - Blood is a “**fluid**” tissue (individual cells working together for a common purpose). ### Blood: The Transport Medium #### The importance of blood - Transport of **gases** (oxygen and carbon dioxide) - Transport of **waste** - Transport of **nutrients** - **Fighting disease and infection** - **Blood clotting** ### Red Blood Cells (erythrocytes) - Has a protein called **hemoglobin** (iron-containing molecule) that carries oxygen to cells in the body. - Produced in the **bone marrow** and has a life span of 120 days. - The body can stimulate the growth of red blood cells when there is reduced oxygen in the blood (e.g., high altitudes). - Lacks a **nucleus**. - Most numerous of the blood cells. ### White Blood Cells (leukocytes) - Fights **germs**, and **foreign cells** harmful to the body. - Has a life span from a few days to a few weeks. - Contains a **nucleus**. ### Platelets - Small particles that initiate **blood clotting** when there is a cut in the skin. - The fluid of blood is called **plasma**. It contains **dissolved** substances that are important to maintain body functions. ## Blood Disorders ### Anemia - Insufficient hemoglobin/iron in red blood cells reduces oxygen-carrying capacity. - Results in tiredness and low energy levels. - Iron supplements often help. ### Leukemia - Cancer of the blood. - Characterized by an increased number of white blood cells in circulation. - White blood cells are immature and incapable of fighting disease. ## The Heart - Composed of **cardiac** muscle which beats **involuntarily**. - Beats an average of **72 times/minute**. - **Two sides** of the heart beat in unison. - **Two sides** of the heart separated by a muscular wall called the **septum**. ### Systole: Contraction of the heart muscle. ### Diastole: Relaxation of the heart muscle. ## Structure of the Heart - The septum separates the **Right Pump** and the **Left Pump**. ## Heart Pumps - Chambers - Each pump contains **two** chambers: - an **atrium** - and a **ventricle** - The heart has **four chambers** total. - Blood flows from **atrium** → **ventricle** ## Heart Chambers - **Atrium:** a thin-walled chamber of the heart that receives blood from the veins. - **Ventricle:** a muscular, thick-walled chamber of the heart that delivers blood to the arteries. ## Diseases and Disorders of the Circulatory System ### Coronary Artery Disease - Coronary arteries provide blood to the **heart muscle tissue**. - Arteries can become **partially blocked** with plaque. - Plaque is a build-up of fat, cholesterol, calcium, and other substances found in blood. - Symptoms: tired, dizzy, pain or burning sensation in arms or chest. - **Angiogram** is used to diagnose this disease. ### Heart Attack - Arteries can become **completely blocked** with plaque or with a **blood clot**. - Heart muscle cells no longer receive the **oxygen** and **nutrients** needed to function. - The heart **stops pumping** and the heart tissue starts to **die**. - Symptoms: chest pain or pressure, shortness of breath, nausea, anxiety, sweating, dizziness. - A **blood test** and **electrocardiogram (ECG)** are used to diagnose a heart attack. - Heart attacks are very serious and life-threatening. ## Summary of Heart Structure <br> - **Superior Vena Cava** - **Right Atrium** - **Right Ventricle** - **Inferior Vena Cava** - **Aorta** - **Pulmonary Artery** - **Pulmonary Vein** - **Left Atrium** - **Left Ventricle** - **Septum** *This was extracted from a document or image, so the styling may not follow all markdown rules. The formatting was generated according to the text and positioning of the provided image/document.*