CARDIOVASCULAR AND

RESPIRATORY SYSTEMS

CIRCULATORY SYSTEM

The circulatory system consists of the heart and blood.
Human life depends on:
The distribution to cells of oxygen, hormones, and nutrients.
The removal of carbon dioxide, and other wastes.
Diagram -- Cardiovascular System

The Heart

The heart is a muscular organ that pumps blood through the body.
The average heart beats 2.5 million times in a typical life span
The typical adult heart:
beats 72 times a minute
pumps about 5.5L per minute
maximum heart rate is 180 to 195 beats per minute with 17.5L of blood racing through it's chambers

Structure

Consists of muscle, nervous and connective tissues
The heart is about the size of a fist and lies within the thoracic cavity (behind the sternum and between the lungs)
The pericardium is a sac like membrane that surrounds the heart and secrets a fluid that reduces friction as the heart beats
Diagram -- Heart structure
The divisions of the heart:
The septum divides the heart lengthwise into two sides
The atria are the two upper chambers of the heart and the ventricles are the two lower chambers.
It has four valves: 2 atrioventricular valves (tricuspid and bicuspid) and 2 semilunar valves (pulmonary and aortic)
Each valve consists of flaps of tissue.
Atrioventricular valves separate the atria from the ventricles and prevent blood from flowing in the wrong chamber
The semilunar valves separate the ventricules from the large vessels through which blood flows out of the heart 
Diagram -- Valve action

Circulation in the Heart

The blood consisting of a high level of carbon dioxide enters the right atrium of the heart.
The atrium pumps it through the tricuspid valve into the right ventricle.
The muscles of the right ventricle contract forcing the blood through the right semilunar valve then through the pulmonary arteries into the lungs.
The now oxygenated blood returns to the heart via the pulmonary veins before entering the left atrium.
The oxygen is pumped into the left ventricle through the bicuspid valve before passing through the semilunar valve and aorta to the rest of the body.

Control of the Heartbeat

The cardiac muscle cells contract in waves.
When the first cell becomes simulated it in turn simulates surrounding cells until the chain is completed contracting all cells.
The wavelike contraction begins in the sinoatrial node, a region of specialized cardiac muscle cells located in the right atrium. It regulates the rate of contraction of the entire heart and generates an electrical charge that stimulates the atria to contract.
Soon after the impulse reaches the atrioventricular node. It delays the impulse for about a millisecond then sends it to the ventricles with an electric charge causing them to contract.
The beat consists of basically two phases, resulting in what we call the heartbeat.
Systole- the ventricles contract and force blood into the arteries
Diastole- the ventricles relax, and the blood flows in from the atria
Diagram -- Regulation of heartbeat

Blood Vessels

Arteries- vessels that carry blood from the heart, aorta is the largest
Arterioles-small artery, capillaries are the smallest in network
Vein- a vessel that carries blood to the heart,
Inferior vena cava- the large vein carrying blood from the lower part of the body.
Superior vena cava- the large vein carrying blood from the upper part of the body.
Venules are the smallest in the network
Diagram -- Blood vessels
Diagram -- Capillaries and tissues

Patterns of Circulation

English scientist William Harvey (1578-1657) showed that the heart and blood vessels formed one continuous, closed system of circulation.
Subsystems:
Pulmonary circulation- between the heart and lungs
System circulation- between the heart and other body tissues
Diagram -- Circulatory system 1
Diagram -- Circulatory system 2

Pulmonary Circulation

The movement of blood between the heart and lungs.
Pulmonary artery- the artery that carries deoxygenated blood from the heart to lungs
Pulmonary veins- the vein that carries oxygenated blood from the heart to lungs

Systemic Circulation

The movement of blood between the heart and all parts of the body except the lungs.
Coronary circulation- the systemic subsystem that supplies blood to the heart.
Coronary artery- a vessel supplying blood to the heart
Renal circulation- a subsystem that involves the movement of blood through the kidneys.
Hepatic portal circulation- moves blood from the digestive tract directly to the liver.

  BLOOD

Blood is the transport medium of the circulatory system.
Its major functions:
To transport nutrients and oxygen to cells throughout the body.
To carry carbon dioxide and nitrogenous wastes away from the cells.
It transfers body heat to the surface of the skin.
It defends the body against disease.

Composition of  Blood

Consists of fifty-five percent (55%) plasma
The other forty-five percent (45%) is made up of blood solids, mostly erythrocytes (red blood corpuscles), white blood cells, and platelet.
Diagram -- Blood- components

Plasma

Sticky fluid which is made up of ninety percent (90%) water.
Contains proteins carrying out specific, important functions.
Fibrinogen helps to form blood clots.
Serum albumin regulates the osmotic pressure between both plasma, blood cells, and tissues.
Serum globulins produce antibodies which help fight disease.
Carries dissolved substances to cells in order to nourish them (Vitamins, Minerals, Amino acids and Glucose).
Carries hormones.
Transports wastes from the cells to the kidneys and lungs to be removed from the body.

Erythrocytes

Erythrocytes are red blood corpuscles (30 trillion).
Vital to the survival of all cells because they transport oxygen.
Contain Hemoglobin
Iron containing protein formed in red bone marrow with erythrocytes.
The molecule that actually transports oxygen and carbon dioxide.
When the corpuscle forms both the nucleus and organelles disintegrate.
Mature erythrocytes are the only membranes containing hemoglobin.
Erythrocytes have a survival period of 120 to 130 days (2 million disintegrate every second).
Remains of membrane are removed by the liver and spleen.
Remaining iron is carried in the blood to the bone marrow where it is used for new cells.

Leukocytes

Leukocytes are white blood cells.
Help defend the body against disease.
Formed in red bone marrow, lymph nodes, and the spleen.
Larger than erythrocytes, but fewer in number.
Irregular shape and a rough outer surface.
Function for many years.
Phagocytes
White cells which engulf invading organisms.
Antibodies
Produced by white blood cells to destroy foreign substances.
When an infection occurs the number of white blood cells increases ten fold.

Platelets

Platelets are also known as thrombocytes.
Not whole cells, but fragments of larger ones with several nuclei which formed in the bone marrow.
Lack a nucleus and survive about seven to eleven days.
Platelets are essential to the formation of blood clots.
Blood clots
 Mass of interwoven fibers and blood cells that prevent excess loss of blood
When blood vessels tear, platelet congregate
Thrombocytes stick together to form a plug
Vessel constricts in order to slow blood flow to the area
Special clotting factors are released to interact with the protein prothrombin to form the enzyme thrombin
Thrombine immediately reacts with the blood protein fibrinogen
Causes fibrinogen to form long sticky threads called fibrin
Fibrin forms a net which traps erythrocytes and then hardens into a scab

Blood Types

Blood carries different chemicals with several functions
Diagram -- Blood types
Diagram -- Rhesus antigen
Antigens
Group of chemicals that simulate the production of antibodies
Three most important antigens are called A, B, and Rh
A, B, O system of blood types is based on A and B antigens
The A, B, O system
Means of classifying blood according to antigens located on the surface of erythrocytes
Erythrocytes may carry A, B, both or neither (alleles)
Called types A, B, AB, and O (phenotypes)
Incompatible blood types such as A and B cause blood to agglutinate or clump and block vessels
Rh Factor
Another type of antigen
Rh- and Rh+ bloods are incompatible, mixing can cause blood to clump and block vessels.
Erythroblastosis fetalis is when the mother is Rh- and the unborn child inherits Rh+ from the father
After the first child the mother develops antibodies to the Rh+ blood that attack the child's blood.
Now anti-Rh antigens are given to the mother after 3 days of birth.
This destroys the Rh antigens before her body makes antibodies

Lymphatic System

 A series of one-way vessels that carries intercellular fluid from tissues to the blood stream.
Lymph- the fluid of the lymphatic system
Diagram -- Lymphatic system

 

  RESPIRATORY SYSTEM

The respiratory system transports gases to and from the circulatory system.
External respiration- exchange of gases between atmosphere and blood.
Internal respiration- exchange of gases between blood and cells.
Cellular respiration- breakdown of glucose in cell.
Diagram -- Respiratory System

Lungs

The lungs are responsible for external respiration.
The right lung has 3 divisions or lobes and it is slightly larger than the left lung which only has two.
The lungs are located in the thoracic cavity and are bound by the rib cage and diaphragm.
Diaphragm- muscle that is at the bottom of the thoracic cavity.
Pleura- lining of cavity, a membrane that secrets mucus to reduce friction.
Diagram -- Respiration- lung structure    
Diagram -- Respiration- respiratory system

Breathing

Inspiration-the process of taking air into the lungs,
Diaphragm muscles contract,
Abdominal muscles relax (providing room for the flattened diaphragm).
Intercostal muscles contract (ribs push out) increasing the volume of the thoracic cavity and decreasing the air pressure inside
Decrease in pressure causes the air to move into the lungs.
Diagram -- Respiration- breathing
Expiration-reverse process

Lung Capacity and Breathing Rate

A lung weighs about 600 g. and can hold 5 to 6 liters of gas, (total lung capacity)
Normally our capacity is 0.5 L but with strenuous exercise we can increase it to 4.5 L
vital lung capacity- maximum amount of air a person can inhale and exhale.
One inhalation and exhalation makes one respiratory cycle
At rest we breath 16 to 24 cycles per min.

Respiration

The steps to respiration:
Respiration begins at the mouth and nose, air filters through the cilia and hairs.
It then goes to be warmed and moistened by mucous membranes.
Moistened and filtered air goes to the pharynx (a tube at the back of the nasal passages) then past the larynx (voice box)
During inhalation the epiglottis is close to the trachea (windpipe).
The trachea branches into two bronchi then smaller tubes called bronchioles and on to the alveoli (tiny air sacs where the exchange of gases takes place).

Gas Exchange

Air moves into the lungs, oxygen is dissolved in the mucus secreted by the alveoli. 
Blood in the capillaries surrounding the alveoli is low in oxygen and contains high levels of carbon dioxide.
Gases move by diffusion.
Oxygen diffuses into the blood and is taken by the plasma and hemoglobin.
Diagram -- Respiration- gas exchange 1 
Hemoglobin transport is one of the most important ways through which oxygen is produced.
Each hemoglobin molecule can carry 4 molecules of oxygen that bind with the central iron atom.
Hemoglobin transports 97% of the oxygen.
Blood reaches the tissues and releases the oxygen that diffuses into surrounding cells.
Diagram -- Respiration- gas exchange 2
Carbon Dioxide transport is completed by:
75% hemoglobin,
67% connected to bicarbonate ions,
8% dissolved in the plasma.
Bicarbonate ions dissolve in plasma and bind to the blood cells.
When the blood reaches the lungs the reverse takes place.
The rate of oxygen use depends on the activity of cells.
Basal metabolic rate- a measure of energy required to maintain bodily functions.
In aerobic respiration carbon dioxide is released, metabolism increases, high levels of carbon dioxide stimulate nerve cells and then stimulate the brain to increase respiration.

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Body Quest
The Virtual Body
Innerbody
St. Mary's Biology - Human Body Service Manual
Leukemia
Heart and Blood vessels
Deaths Due To Circulatory System
Circle of Blood
The Mississippi School for Mathemataics and Science - Circulatory System
How the Body Works-- The Heart
Wadsworth - Circulatory System and Blood
On-Line Biology Book - The Circulatory System (Excellent)
University of Leeds(U.K.) Circulatory System & Blood
Mayo Clinic - Heart
Human Body Atlas - The Arterial System
Mayo Clinic Heart Health Quiz
Human Body Atlas - The Inner Heart
Human Body Atlas - The Heart
Human Body Atlas - The Chest
The Franklin Institute - The Heart: An Online Exploration
The Franklin Institute  - Respiratory System
Mayo Clinic - Lung Conditions
University of Leeds(U.K.) Respiratory System
Mayo Clinic - Circulatory Conditions
Mayo Clinic - Blood Conditions
On-Line Biology Book  THE RESPIRATORY SYSTEM (Excellent)
Wadsworth   - Respiratory System
Lung Cancer Guide
The Mississippi School for Mathemataics and Science - Lymphatic System

Diseases

ANGINA
ANGIOPLASTY, CORONARY
ARRHYTHMIA, PALPITATIONS
BLOOD PRESSURE, HIGH
HEART ATTACK, MYOCARDIAL INFARCTION
VARICOSE AND SPIDER VEINS
BLOOD TRANSFUSION
CANCER, HODGKIN’S DISEASE
CANCER, LEUKEMIA
CANCER, LYMPHOMA, NON-HODGKIN'S
SICKLE CELL DISEASE
THALASSEMIA MINOR & THALASSEMIA MAJOR (COOLEY'S ANEMIA)
ASTHMA
CANCER, LUNG
CYSTIC FIBROSIS
PNEUMONIA
TUBERCULOSIS

  Diagrams modified from Science on File CD