Bio 102 Unit 4 Chapter 32

Front 1

circulatory system

Back 1

an organ system that moves substances (in animals) to and from cells, usually via a heart, blood, and blood vessels.

Front 2

two types of circulatory fluids (Invertebrates)

Back 2

Blood and Hemolymph

Front 3

Blood (Invertebrates)

Back 3

is always contained in vessels and is found in a closed circulatory system.

Front 4

Hemolymph (Invertebrates)

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is a mixture of blood and tissue fluids which fills a body cavity and surrounds the internal organs.

Front 5

Open Circulatory System (Invertebrates)

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hemolymph is pumped by heart (in some) into a cavity called a Hemocoel.
In others, a gastrovascular cavity is involved. Some animals with open circulatory systems system are insects, sea stars, hydras and flatworms

Front 6

Closed Circulatory System (Invertebrates)

Back 6

blood is used and does not leave the vessels.
Blood consists of cells and plasma. A heart pimps blood in vessels going out to body tissues and is returned back to heart. Some animals that have this system are annelids, some molluscs such as squid and octopi.

Front 7

Transport in Vertebrates

Back 7

• All vertebrate animals have a closed circulatory system with vessels and a heart.
• The heart is muscular and consists of atria that receive the blood and ventricles that pump the blood through the vessels.
• Three kinds of vessels: Arteries, Veins and Capillaries.

Front 8

Arteries and Veins have three distinct layers

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o Outer layer that consists of fibrous connective tissue, which is rich in elastic and collagen fibers.
o Middle layer that consists of smooth muscle and elastic tissue
o Inner layer called the endothelium, which is similar to squamous epithelium.

Front 9

Arteries

Back 9

have thick walls, and those attached to heart are resilient and strong. They can expand to accommodate the change in blood volume pumped from heart (the pressure).

Front 10

Arterioles

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are small arteries whose diameter can be regulated by the nervous and endocrine systems.

Front 11

capillaries

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which are extremely narrow, microscopic tubes with walls composed of only one thin layer of cells.

Front 12

Venules and veins

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collect blood from the capillary beds and take it back to the heart.

Front 13

Venules

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drain blood from capillaries and then join to form a vein.

Front 14

Veins

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have a much thinner wall than arteries and special valves within them keep blood flowing one direction towards the heart.

Front 15

Comparison of Circulatory Pathways

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• One circuit (single-loop) seen among fish
• Double circuit (double looped) seem among all other vertebrates

Front 16

One circuit (single loop)

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The heart has a single atrium and single ventricle.

Front 17

One circuit (single loop) Advantage

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The pumping action of ventricle sends oxygen poor blood to the gills where it gets oxygenated and thus the systemic capillaries (capillaries of the body) get the oxygen rich blood.

Front 18

One circuit (single loop) Disadvantage

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after leaving gills, the blood is under reduced pressure (sluggish somewhat compared to other systems).

Front 19

Double circuit (double loop)

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Evolutionary changes in other vertebrates has led to this pathway in which there are two circuits of blood flow: the systemic circuit and the pulmonary circuit. Creates a “double
pumping” action.

Front 20

Systemic circuit

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pumps blood to body tissues

Front 21

Pulmonary circuit

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pumps blood to lung tissue

Front 22

Double circuit (double loop) Advantage

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breathing air on land.

Front 23

Amphibians

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Three chambered heart. Consists of two atria and one ventricle. Oxygen rich blood and oxygen poor blood are kept somewhat separate by the fact that oxygen poor blood exits the ventricle before the oxygen rich blood and the main artery out of the heart is divided.

Front 24

Reptiles

Back 24

Most reptiles also have a three chambered heart with ventricle partially divided by a septum.
Mixing of O2 poor blood and O2 rich blood also kept to a minimum. ***Crocodilians are special in that they are reptiles that have heart chambers fully divided by a septum creating four chambers.

Front 25

Birds & Mammals

Back 25

Four chambered heart fully divided by septum which divides the heart into left and right halves with a right and left atrium and a right and left ventricle. Right ventricle pumps blood to lungs, while larger left ventricle pumps blood to body.

Front 26

Birds & Mammals Advantage

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each circuit has adequate blood pressure

Front 27

The Human Cardiovascular System

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Heart is responsible for pumping blood to the arteries and Skeletal muscle is the main force responsible for movement of blood in the veins through the contraction pressure of those muscles.

Front 28

Structure of the Heart

Back 28

• A cone shaped muscle organ about the size of a fist.
• Located between lungs and under sternum (breastbone).
• Apex (pointed end) is tilted towards the left.
• Myocardium is the major portion of the heart. It consists mostly of cardiac muscle tissue.
o Myocardium receives oxygen and nutrients from the coronary arteries not from the blood it pumps.
o Muscle fibers of myocardium are branched and tightly joined to each other by intercalated disks
• Pericardium: a thick membranous sac that secretes a small quantity of lubricating liquid. The heart is contained within this sac.
• Endocardium: a membrane on the inner surface of the heart which is composed of connective tissue and endothelial cells and is continuous with the endothelia of vessels.
• Septum: An inner wall that separates the left from the right sides
• Heart chambers:
o Two upper thin walled atria (sing. Atrium)
o Two lower chambers that are thick walled called ventricles which pump blood away from the heart.
• Valves: The heart has four different valves.
o Two valves lay between the atria and the ventricles are called atrioventricular valves. These valves are supported by thick cords called chordae tendineae
The one on the right is the tricuspid valve and the one on the left is the bicuspid valve (aka the mitral) .
o Two valves are semilunar valves because they look like halfmoons. These two valves are located between the ventricles and their associated vessels. They are the pulmonary semilunar and the aortic semilunar

Front 29

Myocardium

Back 29

is the major portion of the heart. It consists mostly of cardiac muscle tissue.

Front 30

Pericardium

Back 30

a thick membranous sac that secretes a small quantity of lubricating liquid. The heart is contained within this sac.

Front 31

Endocardium

Back 31

a membrane on the inner surface of the heart which is composed of connective tissue and endothelial cells and is continuous with the endothelia of vessels.

Front 32

Septum

Back 32

An inner wall that separates the left from the right sides

Front 33

Heart chambers

Back 33

o Two upper thin walled atria (sing. Atrium)
o Two lower chambers that are thick walled called ventricles which pump blood away from the heart.

Front 34

Valves

Back 34

The heart has four different valves.
o Two valves lay between the atria and the ventricles are called atrioventricular valves. These valves are supported by thick cords called chordae tendineae
The one on the right is the tricuspid valve and the one on the left is the bicuspid valve (aka the mitral) .
o Two valves are semilunar valves because they look like halfmoons. These two valves are located between the ventricles and their associated vessels. They are the pulmonary semilunar and the aortic semilunar

Front 35

Paths of Blood through the Heart

Back 35

Keep in mind that both the artria and then both the ventricles contract at the same time due to intercalated disks. We can follow path of blood as follows:
1. Blood enters the heart by emptying into right atrium. This blood is oxygen poor and is coming from the body by means of the superior and inferior vena cava (the largest veins in the body).
2. Right atrium sends blood through tricuspid valve to the right ventricle
3. Right ventricle sends blood through the pulmonary semilunar valve into the pulmonary trunk to lungs via the two pulmonary arteries
4. Four pulmonary veins carry oxygenated blood from lungs, back to the heart. This blood enters the left atrium
5. The left atrium sends oxygenated blood through the bicuspid valve to the left ventricle
6. The left ventricle pumps blood into the aorta and on to the rest of the body.
Oxygen poor blood never mixes with the oxygen rich blood. Blood must go to lungs before it goes to the other side of hear. Typical of a double circuit pathway. Left ventricle does the heavy pumping and has the thickest walls.

Front 36

The Heartbeat

Back 36

average human heart beats 70 times a minute. Adds up to about 100,000 beats a day over a 70 year life span give us a figure of 2. 5 billion contractions.
Terms to know:
o Systole
o Diastole
o Cardiac cycle
o Cardiac output
o Pulse
 SA node
 AV node
o Pacemaker

Front 37

The Electrocardiogram

Back 37

ECG. A recording of the electrical changes that occur in the myocardium during a cardiac cycle.
Electrical charges can be detected on the surface of the body due to ions contained in the body fluids that conduct electrical charges.
During the ECG procedure, these changes in charges can be detected by electrodes placed on the body surface. The electrodes are connected to the ECG machine by wires. The changes in electrical currents in the body produce “waves” that are conducted to the machine where they are written on paper.
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When the SA node triggers an impulse, the atrial fibers produce an electrical charge called a P wave.
P wave indicates that the atria are about to contract.
QRS complex signals that the ventricles are about to contract and the atria are about to relax
T wave is produced after the ventricles contract and show the ventricles recovering from the previous contraction.

Abnormalities such as ventricular fibrillation (uncoordinated contractions of the heart) can be detected using the ECG. Ventricular fibrillation is the most common cause of cardiac death. A strong shock can sometimes get the heart contracting again at normal pace.

AED (automatic external defibrillators)

Front 38

AED

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automatic external defibrillators

Front 39

ventricular fibrillation

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uncoordinated contractions of the heart

Front 40

The Pulmonary Circuit

Back 40

the path of blood to lungs can be traced as follows:
• Oxygen poor blood from all regions of body, enters the right atrium
• Blood then passes into the right ventricle
• Blood in right ventricle is pumped into the pulmonary trunk
• Pulmonary trunk divides into right and left pulmonary arteries
• Blood is transported to lungs, and through the pulmonary capillaries where carbon dioxide is given off and oxygen is picked up
• Oxygen rich blood is then transported back to the heart by pulmonary venules . These venules merge to form the pulmonary veins.
• Blood then enters the left atrium

The aorta and the vena cavae are the major blood vessels that transport blood away from the heart to the body and from the body back to the heart. In this system the arteries carry the oxygen rich blood and are red and the veins carry the oxygen poor blood and are blue.

Front 41

The Systemic Circuit

Back 41

path of blood can be traced as follows:
• Oxygenated blood enters the left atrium from the pulmonary circuit.
• Blood enters the left ventricle where it is pumped into the aorta and will be sent out to areas of the body by means of select branches of the aorta.
• Blood then goes along the proper branch of the aorta to a particular organ system
• Blood leaving the organ system will be returned back to the heart via veins which empty into the vena cava ( superior or inferior)

Coronary arteries supply oxygen rich blood to the heart muscle itself and thus are very important.
Cardiac veins remove the oxygen poor blood from the heart

Front 42

Cardiac veins

Back 42

remove the oxygen poor blood from the heart

Front 43

Coronary arteries

Back 43

supply oxygen rich blood to the heart muscle itself and thus are very important.

Front 44

The hepatic portal system

Back 44

is a structure in which blood from capillaries travels through veins to reach another set of capillaries without first traveling through the heart. It takes blood from the intestines directly to the liver where the liver can filter out toxins and metabolize nutrients. The hepatic vein empties into the inferior vena cava.

Front 45

Tracing the path of Blood

Back 45

Example: to and from the leg
• Left ventricle-aorta-common iliac artery-femoral artery-lower leg capillaries-femoral vein-common iliac vein-inferior vena cava-right atrium.
• When the arteries and veins involved are servicing the same area, they are often given the name of that area (hence femoral artery and femoral vein)

Front 46

Blood Pressure

Back 46

Pressure created by the contraction of the heart chambers pushing blood into the arteries.
• Systolic pressure results from blood forced into the arteries during the ventricular systole
• Diastolic pressure is the pressure in the arteries during ventricular diastole
• Human blood pressure can be measured with a sphygmomanometer which is a pressure cuff which determines the amount of pressure needed to stop the flow of blood through an artery.


• Venous return is dependent on three factors:
o Skeletal muscles near veins put pressure on the collapsible walls of the veins
o Valves in the veins prevent backward flow of blood
o Variations in pressure in the chest cavity during breathing (respiratory pump ) cause blood to flow from areas of higher pressure to areas of lower pressure with each inhalation

Front 47

sphygmomanometer

Back 47

is a pressure cuff which determines the amount of pressure needed to stop the flow of blood through an artery.

Front 48

Cardiovascular Disease

Back 48

CVD is the leading cause of death in most Western Countries especially since 1900’s.
1. Hypertension:
2. Atherosclerosis:
3. Stroke and Heart Attack:

Front 49

Blood

Back 49

consists of connective tissue with a fluid matrix. The blood of mammals has a number of function:
• Transports gases, nutrients, waste products and hormones throughout the body
• Combats pathogens
• Helps to maintain water balance and pH
• Regulates body temp
• Carries platelets and factors that ensure clotting to prevent blood loss

Front 50

Plasma

Back 50

• Contains many types of molecules including nutrients, wastes, salts and hundreds of
different types of proteins.
• Some proteins are buffers of pH while others are involved in clotting pathways
• Some are antibodies which are involved in the immune system
• Cholesterol is also transported and so is Albumin, the most plentiful blood protein. Albumin is a protein that transports bilirubin, a breakdown product of hemoglobin.

Front 51

Albumin

Back 51

is a protein that transports bilirubin, a breakdown product of hemoglobin.

Front 52

Red Blood Cells

Back 52

(called erythrocytes) these are biconcave cells that transport oxygen by means of a hemoglobin molecule.
a. RBCs are manufactured in the red bone marrow of the skull, the ribs, the ends of long bones (spongy bone), the vertebra
b. The hormone erythropoietin stimulates the production of RBCs. The kidneys secrete this hormone.
c. Hemoglobin molecules contain iron which loosely bonds to Oxygen and then easily gives it up.
d. Anemia is a result of improper RBC number (not enough) or insufficient iron content. Sickle cell anemia is a genetic disorder where the RBCs are the wrong shape and cannot supply enough oxygen
e. Normally, RBCs live 120 days and are then destroyed by the liver and spleen
f. ABO system of blood types
g. Rh system

Front 53

White Blood Cells

Back 53

(called leukocytes) These are the immune system cells.
a. Discussed more in Chapter 33 but we will go over a brief summary of what WBCs do.
b. These cells are larger, have a nucleus , lack hemoglobin, and without staining appear transparent
c. Fewer WBCs. Approx. 5000-11,000 mm3
d. Granular Leukocytes: have granules filled with enzymes and proteins that these cells use to help defend the body against invading microbes and parasites.
i. Neutrophiles
ii. Basophils
iii. Eosinophiles
e. Agranular Leukocytes: Also called mononuclear cells, lack granules
i. Monocytes
ii. Lymphocytes

Front 54

Platelets

Back 54

(called thrombocytes) These are part of the formation of blood clots.
a. Result from the fragmentation of large cells called Megakaryocytes in the red bone marrow
b. Involved in coagulation (clotting)
c. Platelets and injured cells release a protein called prothrombin activator which is a molecule that converts the plasma protein prothrombin into thrombin but Calcuium ions must be present. Thrombin then acts as an enzyme, cutting two small amino acid chains off of a fibrinogen molecule, which is also a protein in the plasma.
These “activated fragments join together to form a long thread of fibrin. Fibrin makes the mesh that covers a wound and traps platelets like a net, and this along with RBCs form the clot. Later, an enzyme called plasmin destroys the fibrin network and restores the fluidity of plasma.

Read over Capillary Exchange. Study Fig. 32.18