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Chapter 12
The Cardiovascular and Lymphatic
Systems
Mark ManteuffelSt. Louis Community College
Lecture Presentation
The Cardiovascular and Lymphatic Systems
Cardiovascular system Blood vessels Heart Blood pressure
Lymphatic system
The Cardiovascular System: Moving Blood 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 Up the Cardiovascular System
The Cardiovascular System Helps Maintain Favorable Operating Conditions
Blood Circulation Is Essential to Maintain Homeostasis
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 to the Lymphatic System
Lymphatic vessels• Pick up excess extracellular fluid and usable
substances• Return them to the cardiovascular system
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 and Left Halves
The Heart Has Two Halves and Four Chambers 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 Coronary Arteries and Veins
In a “Heartbeat,” the Heart’s Chambers Contract, 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 Travel
Pulmonary & Systemic Circuits
Each Half of the Heart Pumps Blood in a Different Circuit
In the Pulmonary Circuit, Blood Picks Up Oxygen 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 to and 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 a Different Circuit
Systemic and Pulmonary Circulation
http://www.youtube.com/watch?v=0jznS5psypI 0:30
Blood from the Digestive Tract Is 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 Detours to the Liver
Circulatory system
http://www.youtube.com/watch?v=D3ZDJgFDdk0
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 Walls of 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)
http://www.youtube.com/watch?v=tAmLbclSucQ3:01 High Blood Pressure Impacts
A Variety of Factors May Cause Hypertension
Nearly 1 in 3 adult Americans have it.
African Americans are especially at risk.
Learn why hypertension is called the 'silent killer'.
http://www.webmd.com/video/hypertension-silent-killer
3:06
Structure and Functions of Blood Vessels
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 Flows through the Cardiovascular System
Arterioles Are Control Points for Blood Flow
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 Exchanges Substances 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 Brings Blood 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 to Venules
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 Matches Its 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 Cardiovascular Disease
Arteries Can Clog or Weaken: Arteriosclerosis (hardening of the arteries) (1)
Atherosclerosis• Lipids build up in the artery wall• Cholesterol• Trans fats
Atherosclerotic plaque• Narrowing of artery
http://www.youtube.com/watch?v=qRK7-DCDKEA0:39
Plaques and Blood Clots May Clog Arteries
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 Clog Arteries
Heart Damage Can Lead to Heart Attack and 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 Heart Rhythms
Electrocardiogram (ECG)• Recording of the electrical activity of the cardiac
cycle
Arrhythmias: irregular heart rhythms
A Heart-Healthy Lifestyle May Help Prevent 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
Endocarditis• When microbes attack heart valves directly
Borrelia burgdorferi: • may cause heart complications (lyme disease
pathogen)
Strep in green
Infections, Cancer, and Heart Defects (2)
Myocarditis: Heart inflammation; various causes• Bacterial• Alcohol abuse• Drug abuse
The Lymphatic System
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