Circulatory System

What do you know? Why is it important for your heart to continue beating even when you’re sleeping? Why is it important for your heart to continue beating even when you’re sleeping? What does your body need? What does your body need? What are some wastes? What are some wastes?

Circulation and Respiration Each breath brings oxygen rich air into your body Each breath brings oxygen rich air into your body Your cells need that oxygen to do work Your cells need that oxygen to do work Your heart delivers oxygen to your cells Your heart delivers oxygen to your cells Working together, your circulatory and respiratory systems supply cells throughout the body with the nutrients and oxygen that they need to stay alive, and get rid of waste that would kill you Working together, your circulatory and respiratory systems supply cells throughout the body with the nutrients and oxygen that they need to stay alive, and get rid of waste that would kill you

Cardiovascular/Circulatory System The circulatory system transports substances including oxygen, nutrients and wastes to and from cells The circulatory system transports substances including oxygen, nutrients and wastes to and from cells

Components of the System The human circulatory system consists of: The human circulatory system consists of: –The heart –Blood vessels –Blood

The Heart Located near the center of your chest Located near the center of your chest A hollow organ about the size of your fist A hollow organ about the size of your fist Made of cardiac muscle tissue Made of cardiac muscle tissue The heart contracts about 72 times a minute The heart contracts about 72 times a minute

The Heart Right side: oxygen-poor to lungs (blue) Right side: oxygen-poor to lungs (blue) Left side: oxygen-rich to body (red) Left side: oxygen-rich to body (red) Atria Atria Ventricles Ventricles Valves Valves heart video heart video heart video heart video

Blood vessels Hollow tubes that carry blood Hollow tubes that carry blood –Arteries –Capillaries –Veins

Arteries Large vessels that carry blood AWAY from the heart to tissues of the body Large vessels that carry blood AWAY from the heart to tissues of the body Usually carry oxygen-rich blood. Usually carry oxygen-rich blood. Arteries have thick walls of tissue, withstand the powerful pressure produced when the heart contracts and pushes blood into the arteries. Arteries have thick walls of tissue, withstand the powerful pressure produced when the heart contracts and pushes blood into the arteries.

Capillaries The smallest of the blood vessels connecting arteries and veins The smallest of the blood vessels connecting arteries and veins Walls are one cell thick allowing for easier diffusion of nutrients and oxygen from capillaries to body cells and wastes and carbon dioxide from body cells to capillaries Walls are one cell thick allowing for easier diffusion of nutrients and oxygen from capillaries to body cells and wastes and carbon dioxide from body cells to capillaries

Veins Return blood to the heart Return blood to the heart Veins have walls of connective tissue and smooth muscle Veins have walls of connective tissue and smooth muscle Large veins contain valves that keep blood flowing towards the heart Large veins contain valves that keep blood flowing towards the heart

Veins vs. Arteries

Types of Circulation Pulmonary circulation = from right side of the heart to lungs where carbon dioxide leaves the blood and oxygen is absorbed Pulmonary circulation = from right side of the heart to lungs where carbon dioxide leaves the blood and oxygen is absorbed Systemic circulation = from left side of the heart to organs Systemic circulation = from left side of the heart to organs

Figure 37-2 The Circulatory System Capillaries of head and arms Capillaries of abdominal organs and legs Inferior vena cava Pulmonary vein Capillaries of right lung Superior vena cava Aorta Pulmonary artery Capillaries of left lung

Coronary Circulation Remember: the heart is an organ and needs nutrients, oxygen and creates wastes. Remember: the heart is an organ and needs nutrients, oxygen and creates wastes. Blood flows to the tissues of the heart too! Blood flows to the tissues of the heart too!

Blood Pressure The heart produces pressure when it contracts. The heart produces pressure when it contracts. The force of blood on the arteries’ walls = blood pressure The force of blood on the arteries’ walls = blood pressure Blood pressure decreases when the heart relaxes, but there must always be some pressure to keep the blood flowing Blood pressure decreases when the heart relaxes, but there must always be some pressure to keep the blood flowing Doctors measure blood pressure with a sphygmomanometer recording two numbers Doctors measure blood pressure with a sphygmomanometer recording two numbers –Systolic pressure = force felt in arteries when ventricles contract –Diastolic pressure = force of blood felt in arteries when ventricles relax Average adult’s blood pressure = 120/80 Average adult’s blood pressure = 120/80

Cardiovascular Problems Heart disease is the leading cause of death in America Heart disease is the leading cause of death in America Atherosclerosis = fatty deposits (plaque) builds up on walls of arteries, obstructing blood flow, Atherosclerosis = fatty deposits (plaque) builds up on walls of arteries, obstructing blood flow, –increasing blood pressure – risk of blood clots –Risk of heart attack

Heart Attack An artery that supplies blood to the heart becomes blocked An artery that supplies blood to the heart becomes blocked

High Blood Pressure Also known as Hypertension Also known as Hypertension Forces heart to work harder, which may weaken or damage the heart muscle and vessels Forces heart to work harder, which may weaken or damage the heart muscle and vessels Can lead to heart disease, heart attack and stroke

Prevention Cardiovascular diseases are easy to prevent: Cardiovascular diseases are easy to prevent: –Exercise – increases respiratory system’s efficiency –Weight control – reduces body fat and stress –Sensible diet – low in saturated fat reduces risk of heart disease –Not smoking – reduces risk of heart disease

Blood Function: to carry oxygen and nutrients to all parts of your body

Plasma Fluid part of blood Fluid part of blood Water, minerals, nutrients, sugars, proteins and other substances. Water, minerals, nutrients, sugars, proteins and other substances.

Red Blood Cells Carry oxygen Carry oxygen Hemoglobin: an oxygen-carrying protein molecule Hemoglobin: an oxygen-carrying protein molecule

Platelets Pieces of larger cells found in bone marrow Pieces of larger cells found in bone marrow Clump together and release chemicals that cause blood to clot Clump together and release chemicals that cause blood to clot

White Blood Cells Cells that fight pathogens Cells that fight pathogens –Some destroy –Others release chemicals that destroy –others kill damaged body cells

Blood and Homeostasis Plays a vital role in carrying almost all substances throughout the body. Plays a vital role in carrying almost all substances throughout the body. Regulates temperature Regulates temperature –Vessels dilate when you are hot, release heat to skin

Blood types A, B, AB or O A, B, AB or O Refers to the type of chemicals you have on the surface of your RBCs Refers to the type of chemicals you have on the surface of your RBCs

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