Circulatory System

OBJECTIVES:

• Understand the anatomy and functions of the circulatory system

• Know how the circulatory system maintains homeostasis

• Know several diseases of the circulatory system

Circulatory System

I. Overview

A. Functions of the Circulatory System (CS)

1. Internal transport system

2. Delivers O2 and nutrients to cells

3. Removes CO2 and metabolic wastes from cells

4. Interacts with digestive, respiratory and excretory systems to maintain homeostasis

Circulatory System

I. Overview (cont)B. Two Types of circulatory systems

1. Open CSa. Found in smaller and simpler organisms

(e.g. arthropods and mollusks) b. Blood is pumped into open spaces called

sinuses.2. Closed CS

a. Found in larger and more complex organisms (e.g. earthworms and

vertebrates) b. Blood stays in vessels and is pumped in a loop

under pressure.

Circulatory System

I. Overview (cont)C. The human circulatory system is comprised of three

components: the heart, blood vessels and blood

II. The HeartA. Function

1. Pump blood throughout the body

B. Structure

1. The heart is surrounded by a thin protective sac called the pericardium

2. The majority of the heart is muscle called the myocardium

Circulatory System

C. Factors that Affect Heart Rate

1. Blood Pressure - increase in BP will cause an increase in HR

2. Increase in Carbon Dioxide in blood will cause an increase in HR

3. Gender - females have higher HR than males4. Age - the older you get the lower your HR Temperature - as body temperature increases so

does HR

Circulatory System

Circulatory System

III. Blood Vessels (3 Main Types)A. Arteries

1. Thick walled and muscular2. Carry blood AWAY from the heart to tissues

and organs Why are arteries thick-walled and muscular? Do arteries always carry oxygenated blood?

Circulatory System

B. Capillaries

1. Walls are very thin and porous: one-cell thick and very narrow (WHY?)

2. Exchange of materials (Which materials?)

Circulatory SystemC. Veins

1. Thin-walled and muscular2. Carries blood TOWARDS the heart3. Many are located near and between skeletal

muscles (WHY?)4. Large veins contain valves (WHY?)

What happens if we sit or stand too long? Do veins always carry deoxygenated blood?

Circulatory System

IV. Blood A. Human body contains 4-6 liters B. Composed of 45% cells and 55% plasmaC. Blood Plasma

1. 90% water2. 10% is made of:

a. Dissolved gasses (Which two?)b. Saltsc. Enzymes and other proteinsd. nutrientse. Liquid wastesf. Hormones

Circulatory System

D. Types of Blood Cells (3 Types)1. Red Blood Cells (Erythrocytes):

a. Transport oxygen using special iron-containing protein called hemoglobin that binds oxygenb. Disk-shapedc. Produced from cells in red bone marrowd. Have no nucleus and die after ~100 days

Circulatory System

2.2. WhiteWhite Blood Cells (Leucocytes)a. Protect the body against infectionb. Use phagocytosis to engulf pathogens

Circulatory System

3. Platelets (Thrombocytes): a. Stimulate the formation of blood clots b. Platelets come into contact with a damaged blood vessel.c. The platelets rupture releasing clotting factorsd. The platelet factors reacts with factors in the plasma

forming a clot.e. This process occurs with in minutes.

V. Disorders of the blood

A. Anemia (a reduction in bloods ability to carry oxygen)1. Cause by: lack of iron, reduce RBC formation,

excessive bleeding or it can be genetic(Thalassemia)2. Symptoms: lack of energy3. Treatment: dietary adjustments or drugs

B. Leukemia1. Caused by an uncontrollable production of immature

leukocytes.2. Symptoms: Inability to fight off infection3. Treatment: Bone marrow transplants, radiation and

chemotherapyC. Hemophila and Sickle-Cell Anemia

1. Look back at your genetics notes.

VI. Disorders of the Blood Vessels

A. Varicose Veins1. Cause - valves in the veins fail and blood over

stretches the veins2. Symptoms - large protruding veins, painful3. Treatment - surgery or injections to collapse smaller

ones.4. Prevention – exercise, don’t cross legs over knees.

** Hemorrhoids are varicose veins in the rectum.

B. Aneurysm1. Hereditary, artery wall is weakened.2. Symptoms - none!3. Treatment - immediate surgery

VII. Cardiovascular Disease

B. Most common form is Coronary Heart Disease 1. Cause

a. Slow build up of fatty plaque (atherosclerosis) along the walls of the coronary arteries

b. Reduced blood flow to heart leads to a heart attack2. Diagnosis

a. Outward symptoms of a heart attack• pain in chest and left arm• cyanosis of lips• nausea and a cold sweat• dizziness• shortness of breath• denial!!!

A. Kills over 1 million Americans a year!

b. Lab Tests1. Exercise EKG2. Angiogram

a. A small tube is inserted into an artery of pelvis and worked into the aorta

b. Dye is injected into the arteryc. A fluoroscope will show where the dye goesd. Blocked arteries don’t show up

3. Treatmenta. Coronary bypass surgery1. Remove a vein from the leg2. Graft the vein to the aorta and an unblocked portion of

the artery.

VII. Cardiovascular Disease

3. Treatment (cont.)b. Angioplasty

1. A small tube with a balloon at the end is inserted into an artery in the leg.

2. The tube is manipulated into the block artery of the heart.

3. The balloon is inflated.4. The fatty plaque is smashed up against

the artery wall5. Sometimes a stint is placed in the artery to

keep the artery open

C. Stroke (The interruption of blood flow to the brain)

1. Causes

a. Blood clot

b. Atherosclerosis

c. An aneurysm

D. Risk Factors associated with Heart Disease (Check your parents!)

1. age2. gender3. genetics4. diets high in fat (hyperlipidemia)5. high blood pressure6. smoking7. stress8. alcohol9. obesity10. inactivity

E. Designing A Good Aerobic Exercise Program

1. Work at the correct intensity as measured by heart rate

athlete 80-90% of the max. HRnormal 70-80% of the max. HRolder 60-70% of the max. HR

(Maximum HR= 220 — age)

*** e.g. a normal person 40 years of age(220-40) x 70%180 x 0.7 =126.0 beats/min.

2. Work for at least 20 minutes or longer 3. Work at least 3 to 4 times a week4. You can do any form of exercise that allows you to meet the first

three requirements.