Human Circulatory System

Which blood is blue?

What is blood?~ 5 liters in adult body~ 54% plasma~ 45% red blood cells (RBCs)~ < 1% white blood cells (WBCs) & platelets

What does blood do?

1. Transport of Gases:• Oxygen O2 is transported from the lungs

to the cells.• CO2 waste is transported from the cells to

the lungs.

2. Transport Nutrients -to cells:• For example, glucose, a sugar monomer used to• produce cell energy=ATP in the mitochondria

3. Waste Removal – closely related to circulatory system• Blood brings waste to the lungs, liver and kidneys to get rid of waste• The kidneys remove liquid waste = Urea which is then excreted in the

urine.

4. Transport hormones – • that help maintain constant internal conditions.

5. Contains white blood cells that fight infection.

• normal red blood cell - carries oxygen

• Platelet - blood clotting• white blood cell – fights infections

Make a quick sketch of these cells and label them.

6. Homeostasis: • Helps stabilize the pH and concentration of the body fluids.• It helps maintain body temperature by transporting heat.

Red blood cells - (erythrocytes)

• O2 > liver signals for RBCs to be produced• RBCs made from stem cells in bone marrow (erythropoiesis)• RBCs are packed with hemoglobin proteins (iron containing protein that binds

to oxygen giving blood its red color)• RBCs lack nucleus and most organelles • Only live about 100-120 days• Disposed of by macrophages (big-eaters)

RBCs are like O2 sponges utilizing 98.5% of available oxygen. They are limited only by their ability to transport O2…not by availability of O2.

Why do erythrocytes torpedo their own nucleus when they are young (and also lack

other organelles)?

RBC video

RBCs take about 20 seconds per lap around the circulatory system!

RBC circle gif link

Arteries, Veins and Capillaries

Arteries – • Thick and muscular to accommodate higher pressure. • Carry blood away from heart.• Smooth walls to reduce resistance• Elasticity allows high pressure• Smaller arteries are called arterioles

Veins – • Thinner-walled than arteries• Lower pressure• One-way valves to prevent backflow• Smaller veins are called venules• Movement of skeletal muscle helps propel blood

What happens if you don’t move enough?

What happens if some of these valves fail?

Capillaries – • Tiny, thin and fragile blood vessels.• Extremely profuse• Capillaries are where fluids, gasses, nutrients, and wastes

are exchanged between the blood and body tissues

Structure and function of the human heart

Some old beliefs about the heart still linger…

72 beats per minute during an average lifespan of 75 years.

72 beats per minute x 60 = 4,320 beats per hour.

4,320 beats per hour x 24 = 103,680 beats per day.

103,680 beats per day x 365 = 37,843,200 beats per year.

37,843,200 beats per year x 75 = 2,838,240,000 beats in an average lifetime

The only “real” time piece?

The two atrioventricular (AV) valves, which are between the atria and the ventricles, are the mitral valve and the tricuspid valve.

The two semilunar (SL) valves, which are in the arteries leaving the heart, are the aortic valve and the pulmonary valve.

About the size of your fistSlightly tilted to the left~72 bpm averageIntrinsic conductionCardiac circulatory system

Why is the right ventricle cavity bigger than the left ventricle ?

Coronary Arteries

The ABO Blood Group System

There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells:

• Group A – only the A antigen on RBCs (B antibody in the plasma)

• Group B – only the B antigen on RBCs (A antibody in the plasma)

• Group AB – both A and B antigens on RBCs (neither A nor B antibody in the plasma)

• Group O –neither A nor B antigens on RBCs (both A and B antibody are in the plasma)

Hemolytic Disease of the Newborn (HDN)

• Rh or ABO incompatibility newborn/mother• Foreign proteins identified - attacked • Immune system causes clumping and lysis of RBCs• More likely with 2nd pregnancy• Med available to avoid problems if Rh- known • Every mother tested

Blood Coagulation

Damage Extrinsic

DamageIntrinsic

• Initiated by tissue factors• Platelets > fibrin > WBCs/RBCs• Blood release stopped

• platelet > fibrin > WBCs/RBCs• Forms thrombus• Released thrombus = embolus

Clots inhibited by blood factors and endothelial secretions

Stroke

• Blockage or rupture of blood vessel in brain.• Hemorrhagic – hypertension, weak vessels• Ischemic - thrombus or embolism• Loss of function, death or paralysis.

Systole – When the ventricles contract

Diastole – when the ventricles are relaxed

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• Most common arrythmia• Tachycardia• May have no symptoms, palpitations, angina, CHF, shortness of breath, edema• Treat with drugs and/or defibrillation

Atrial Fibrillation

• Uncoordinated contraction = quivering• Quickly results in asystole• Often due to ischemic heart disease• Possibly corrected with quick use of electrical defib

Ventricular Fibrillation

video

• Any number of diseases including coronary artery disease, heart-failure and angina.

• Heart Disease = #1 killer in U.S.

Cardiovascular Disease

• Atherosclerosis = Fatty deposits in vessel walls = narrowing• leads to blockage of coronary arteries

• Partially blocked > angina• Full blocked > myocardial infarction• Collateral circulation

Coronary Artery Disease

Coronary Artery Disease

• uncomfortable pressure• Fullness• squeezing pain• pain in shoulders, neck and arms (especially left)

Heart is not working efficiently

Some causes:Arteriosclerosis, hypertension, myocardial infarction, etc.

video

Congestive Heart Failure