Ch10 or 12 circulatory system
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Ch10 or 12 circulatory system






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Ch10 or 12 circulatory system Ch10 or 12 circulatory system Presentation Transcript

  • Chapter 12 TheCardiovascularand Lymphatic SystemsLecture Presentation Mark ManteuffelSt. Louis Community College
  • The Cardiovascular and LymphaticSystems  Cardiovascular system  Blood vessels  Heart  Blood pressure  Lymphatic system
  • The Cardiovascular System: MovingBlood through the Body The cardiovascular system (or circulatory system) is built to rapidly transport blood to every living cell in the body Consists of the heart and blood vessels The system helps maintain homeostasis by providing rapid internal transport of substances to and from cells
  • The Heart and Blood Vessels Make up the Cardiovascular System Cardiovascular system 1) Heart 2) Blood vessels • Arteries: large diameter • Arterioles: smaller & narrower vessels • Capillaries: even narrower • Capillary beds: slow flowing blood moves through these vast numbers of slender capillaries- substances diffuse into and out of these from cells • Venules: blood flows from capillaries into these small vessels • Veins: from venules to larger veins that return blood to heart
  • The Heart and Blood Vessels Make Upthe Cardiovascular System
  • The Cardiovascular System HelpsMaintain Favorable Operating Conditions
  • Blood Circulation Is Essential to MaintainHomeostasis Major role in homeostasis Blood brings oxygen, nutrients, and hormones to cells Blood removes waste products from cells and excess heat
  • The Cardiovascular System Is Linked tothe Lymphatic System Lymphatic vessels • Pick up excess extracellular fluid and usable substances • Return them to the cardiovascular system • More on this later
  • The Heart: A Double Pump In a lifetime of 70 years, the human heart beats some 2.5 billion times This durable pump is the centerpiece of the cardiovascular system
  • The Heart Is Divided into Right andLeft Halves
  • The Heart Has Two Halves and FourChambers Septum: thick wall divides heart in half Chambers of the heart • 2 Atria • 2 Ventricles Coronary arteries: branch off of the aorta, the major artery carrying oxygenated blood away from the heart
  • The Heart Itself Is Served by CoronaryArteries and Veins
  • In a “Heartbeat,” the Heart’s ChambersContract, Then Relax “Heartbeat”: one cycle of contraction and relaxation of the heart chambers Cardiac cycle • Systole • Diastole • “Lub-dup” Cardiac output • Every 60 seconds ~5 liters/ventricle
  • Blood TravelPulmonary & Systemic Circuits
  • Each Half of the Heart Pumps Blood in aDifferent Circuit
  • In the Pulmonary Circuit, Blood Picks UpOxygen in the Lungs Pulmonary Circuit • Blood from tissue circulates through the lungs for gas exchange • Role of pulmonary arteries and veins
  • Heart  The right side of the heart • Contains blood low in oxygen • Pumps blood through the pulmonary circuit • Transports blood to and from the lungs  The left side of the heart • Contains blood rich in oxygen • Pumps blood through the systemic circuit • Transports blood to and from body tissues
  • In the Systemic Circuit, Blood Travels toand from Tissues Systemic circuit • Oxygenated blood pumped by left side of heart moves through body and returns to left atrium Aorta • Major arteries branch off it
  • Each Half of the Heart Pumps Blood in aDifferent Circuit
  • Systemic and Pulmonary Circulation 0:30
  • Shunted through the Liver for Processing Hepatic portal system: the vessels involved in this detour • Hepatic portal vein: nutrient-laden blood • Hepatic vein: blood leaving the liver’s capillary bed enters the general circulation through this vein • Hepatic artery: the liver receives oxygenated blood via this artery • The liver removes impurities and processes absorbed substances
  • Blood from the Digestive Tract Detoursto the Liver
  • Circulatory system 2:58
  • Blood Pressure Heart contractions generate blood pressure, which changes as blood moves through the cardiovascular system Blood pressure is highest in the aorta Then it drops along the systemic circuit
  • Blood Exerts Pressure against the Wallsof Blood Vessels Blood pressure: fluid pressure that blood exerts against vessel walls Systolic and diastolic pressure: 120/80 • Systolic pressure: The peak pressure in the aorta while the left ventricle contracts and pushes blood into the aorta • Diastolic pressure: The lowest blood pressure in the aorta, when blood is flowing out of it and the heart is relaxed Hypertension • Chronically elevated blood pressure Hypotension • Abnormally low blood pressure
  • Blood Pressure Values (mm of Hg) 3:01 High Blood Pressure Impacts
  • A Variety of Factors May CauseHypertension
  •  Nearly 1 in 3 adult Americans have it. African Americans are especially at risk. Learn why hypertension is called the silent killer. silent-killer 3:06
  • Structure and Functions of BloodVessels As with all body parts, structure is key to the functions of blood vessels All our vessels transport blood, but there are important differences in how different kinds manage blood flow and blood pressure
  • Blood Pressure Changes as Blood Flowsthrough the Cardiovascular System
  • Arterioles Are Control Points for BloodFlow Wall built of smooth muscle rings over elastic tissue • Dilates when smooth muscle relaxes • Constricts when smooth muscle contracts Offer more resistance to blood flow than other vessels do
  • Capillaries: Where Blood ExchangesSubstances with Tissues Blood enters the systemic circulation moving swiftly in the aorta, but this speed has to slow in order for substances to move into and out of the bloodstream
  • Capillaries Are Specialized for Diffusion Thinnest wall of any blood vessel • Single layer of endothelium Site of diffusion of gases, nutrients, and wastes Extensive • 62,000 miles Blood pressure drops slowly as blood flows through them
  • Some of the Substances Pass through“Pores” in Capillary Walls Pores • Filled with water • Passages for substances that can dissolve in water Fluid movement in capillaries • “Bulk flow”: water and solutes forced out of the vessel • Lymph vessels return the fluid to the blood
  • A Vast Network of Capillaries BringsBlood Close to Nearly All Body Cells 40 billion capillaries Every cell is a diffusible distance away from a capillary Blood flow is slowest in the capillaries
  • Blood in Capillaries Flows Onward toVenules Capillaries branch into capillary beds
  • Blood Vessels  Venules • Capillaries merge to form venules, the smallest kind of vein • Venules join to form larger veins  Veins • Carry blood back to the heart • Walls have the same three layers as arteries, but they are thinner; also have larger lumens • Serve as reservoirs for blood volume
  • Venules and Veins Return Blood to the Heart Venules • Function somewhat like capillaries Veins • Large diameters and low-resistance transport of blood back to the heart • Outer layer of connective tissue • Middle layer of smooth muscle and elastic fibers • Inner layer of endothelium • Valves prevent backflow of blood • Varicose veins: overstretched over time due to weak valves
  •  Varicose veins are gnarled, enlarged veins that most commonly affect legs and feet. The reason for this is gravity. Walking upright increases pressure in the veins in the lower part of the body, which can cause varicose veins. In most cases they are harmless, and simply a cosmetic concern. • However, for others it can be very painful and cause severe discomfort. • In some, rare cases, it can lead to more serious problems, such as severe disorders of the circulatory system.
  • The Structure of a Blood Vessel MatchesIts Function
  • Cardiovascular Disease
  • Cardiovascular Disease Major risk factors • Genetics • High levels of blood lipids, e.g., cholesterol and trans fats • Hypertension • Smoking, obesity, and lack of exercise • Age Infection-related inflammation • Can promote the formation of artery-blocking plaques and C-reactive protein • Produced by the liver in response to above; can lead to heart disease Too much homocysteine: an amino acid that is released as certain proteins break down; too much in the blood may cause damage leading to atheroslerosis
  • Major Risk Factors for CardiovascularDisease
  • Arteries Can Clog or Weaken: Arteriosclerosis(hardening of the arteries) (1) Atherosclerosis • Lipids build up in the artery wall • Cholesterol • Trans fats 0:39 Atherosclerotic plaque • Narrowing of artery
  • Plaques and Blood Clots May ClogArteries
  • Arteries Can Clog or Weaken (2) Coronary arteries • Narrow and vulnerable to clogging by plaques • Angina pectoris (mild chest pain) • “Plaque-busting” drugs: statins • Ways to repair coronary blockage • Coronary bypass • Laser angioplasty • Balloon angioplasty • Aneurysm • When a weakened artery wall balloons outward, creating a pouchlike weak spot • Could be fatal if it bursts
  • Plaques and Blood Clots May ClogArteries
  • Heart Damage Can Lead to Heart Attackand Heart Failure Heart attack • Damage or death to cardiac muscle • Warning signs • Risk factors Heart Failure (HF) • Weak heart and ineffective pump • Even walking can become difficult • May require repeated hospitalization
  • Arrhythmias Are Abnormal HeartRhythms Electrocardiogram (ECG) • Recording of the electrical activity of the cardiac cycle Arrhythmias: irregular heart rhythms
  • A Heart-Healthy Lifestyle May HelpPrevent Cardiovascular Disease Benefit of a diet that is moderate in fats Regular exercise Do not smoke
  • Infections, Cancer, and Heart Defects (1) Infections may seriously damage the heart Streptococcus bacteria: Rheumatic fever Strep in green  Endocarditis • When microbes attack heart valves directly Borrelia burgdorferi: • may cause heart complications (lyme disease pathogen)
  • Infections, Cancer, and Heart Defects (2) Myocarditis: Heart inflammation; various causes • Bacterial • Alcohol abuse • Drug abuse
  • The Lymphatic System Next…