o bjective the role of the circulatory system and its key organs. blood is a moving tissue...
TRANSCRIPT
OBJECTIVE The role of the circulatory system and its key organs. Blood is a moving tissue containing blood, cells,
oxygen, carbon dioxide, nutrients, hormones and waste products.
The role of red blood cells and how hemoglobin aids in oxygen transportation.
The anatomy and function of the heart as a four chamber pump.
The role of arteries, veins and capillaries. The heart cycle during systole and diastole. What lifestyle factors contribute to the development of
heart disease. The the sickle cell anemia affects oxygen transport to
cells. How maintaining fitness can lead to a health body. The role of blood cells.
PHYSIOLOGY The function of all of the bodies organs and
systems.
All the bodies organs are required to function within certain parameters. What this achieves is homeostasis.
What is homeostasis?Homeostasis is the state of relative constancy in
the internal environment of the body. Food and water is converted into energy and is used to fuel the body.
Among the most important ways that humans maintain homeostasis is by regulating their own body temperature and PH automatically.
Its role is to transport useful substances like oxygen, amino acids and glucose around the body while removing waste substances like carbon dioxide and urea. This done by the heart circulating blood through the entire body to help maintain helping to maintainhomeostasis.
Both gas exchange and nutrient for waste exchange occur across the walls of the smallest blood vessels- capillaries.
Completely contained within a network of vesselsknown as a closed circulatory system.
What is the Circulatory System? Like any
other organ system the circulatory system is a collection of specialized cells, tissues and organs. Consists of the heart, blood and blood vessels.
This system pumps blood faster and this is why it is suitable for animals with a high metabolic rate. These animals are active and their digestion is fast, so is the process of elimination of waste from the body.
SOME INVERTEBRATES DO NOT HAVE A CIRCULATORY SYSTEM Cnidarians, such as hydras, and flatworms, such as planarians, do not have a
circulatory system In a hydra
The cells are either part of an external layer, or they line the gastrovascular cavity
In either case, each cell is exposed to water and can independently exchange gases and get rid of wastes
In a planarian Trilobed gastrovascular cavity branches throughout the small, flattened
body No cell is very far from one of the three digestive branches, so nutrient
molecules can diffuse from cell to cell
OTHER INVERTEBRATES HAVE AN OPEN OR A CLOSED CIRCULATORY SYSTEM
There are two types of circulatory fluid: Blood - always contained within blood vessels Hemolymph - a mixture of blood and tissue fluid that flows into a
body cavity Open circulatory system - found in arthropods and molluscs
Heart pumps hemolymph via vessels into tissue spaces and eventually hemolymph drains back to the heart
Slow delivery of oxygen and nutrients is sufficient for a sluggish animal (clam)
A grasshopper has colorless blood and doesn’t depend on its open circulatory system to deliver oxygen to its muscles
Tracheae open to outside and take oxygen directly to flight muscles Closed circulatory system - found in annelids (earthworms)
Heart pumps blood, which usually consists of cells and plasma, into a system of blood vessels and valves prevent the backward flow of blood
Blood moves into capillaries, for exchanges with tissue fluid Blood then moves from small veins into the dorsal blood vessel (a
vein) This dorsal blood vessel returns blood to the heart for repumping
ALL VERTEBRATES HAVE A CLOSED CIRCULATORY SYSTEM Two different circulatory pathways in vertebrates
Single-loop: heart only pumps blood to gills Two-circuit: systemic circuit - heart pumps blood to all parts
of the body except for the lungs; the pulmonary circuit - heart pumps blood to the lungs
Fishes - heart has a single atrium and a single ventricle Blood is fully enriched with oxygen when it leaves gills, the
respiratory organ for aquatic organisms Amphibians and Reptiles - single ventricle pumps blood
in the pulmonary circuit to the lungs Also pumps blood in the systemic circuit to the rest of the body Although both O2 -rich and O2 -poor blood enter the single
ventricle, it is kept separate O2 -poor blood is pumped out of the ventricle to the lungs before O2-
rich blood enters and is pumped to the systemic circuit Birds and Mammals
Two atria and two ventricles in the heart and the complete separation of the pulmonary and systemic circuits
Right ventricle pumps blood under pressure to the lungs, and the larger left ventricle pumps blood under pressure to the rest of the body
THE MAMMALIAN CARDIOVASCULAR SYSTEM CONSISTS OF THE HEART AND BLOOD VESSELS
Complete separation of pulmonary and systemic circuits in birds, mammals, and some reptiles
THE HEART An organ that supplies blood carrying oxygen to all
parts of the body.
The heart is located in the chest cavity just behind the breastbone and between the lungs.
The outer wall of the human heart is composed of three layers.
The outer layer is called pericardium .
The middle layer is called the myocardium and is composed of muscle which contracts.
The inner layer is called the endocardium and is in contact with the blood that the heart pumps.
• Cardiac muscle needs a reliable supply of oxygen. The coronary arteries supply blood to the heart itself.
ANATOMY OF THE HEART.* 4 CHAMBERS: LEFT AND RIGHT ATRIUMS.* LEFT AND RIGHT VENTRICLES.* AORTA* PULMONARY ARTERY* PULMONARY VEINS* VENA CAVA.
Aorta
Pulmonary artery
Pulmonary veins
Left atrium
Left ventricle
Right ve n t r i c l e
Right atrium
Vena cava
PHYSIOLOGY OF THE HEART.The right side of the heart pumps deoxygenated
blood to the lungs.
Venous blood from the body enters the right atrium via the vena cava.
The blood flows from the right atrium into the right ventricle. Valves prevent blood from flowing back.
The right ventricle squeezes and pumps the venous blood to the lungs via the pulmonary arteries.
In the lungs, the blood picks up oxygen, and carbon dioxide is removed.
The left side of the heart pumps oxygenated blood from the lungs to the rest of the body.
Oxygen-rich blood from the lungs enters the left atrium of the heart.
Blood is pumped from the left atrium into the left ventricle.
The left ventricle contracts and pumps the oxygen-rich (arterial) blood to the body via the aorta.
http://The circulatory system
Blood passes through the heart twice during a complete circuit-normally 45 seconds.
HEART VALVES
Atrioventricular valves - between the atria and ventricles
Semilunar valves - between the ventricles and their attached vessels
After the blood passes through the right atrioventricular valve, the right ventricle pumps it through the pulmonary semilunar valve into the pulmonary trunk and pulmonary arteries that take it to the lungs Pulmonary veins bring O2-rich blood back to the
left atrium After the blood passes through the left
atrioventricular valve, the left ventricle pumps it through the aortic semilunar valve into the aorta, which takes it to the tissues Heart murmur is often due to leaky atrioventricular
valves, which allow blood to pass back into the atria after they have closed
THE HEARTBEAT IS RHYTHMIC The average human heart contracts, or beats, about
70 times a minute, or 2.5 billion times in a lifetime Each heartbeat, called the cardiac cycle, can be
divided into three phases The atria contract (while the ventricles relax) The ventricles contract (while the atria relax) All chambers rest
Systole refers to contraction of the heart chambers, and the word diastole refers to relaxation of these chambers
When the heart beats, the familiar “lub-dub ” sound is heard as the valves of the heart close Pulse - wave effect that passes down walls of arterial
blood vessels following ventricular systole Rhythmic contraction of heart is due to cardiac
conduction system The SA (sinoatrial) node initiates the heartbeat every
0.85 seconds and is called the cardiac pacemaker An electrocardiogram (ECG) is a recording of the
electrical changes that occur in the heart during a cardiac cycle
ARTERIES The main artery of the heart divides and branches out into
many smaller arteries so that each region of your body has its own system of arteries supplying it with fresh, oxygen-rich blood.
Arteries are tough on the outside and smooth on the inside to allow blood to flow.
When the heart beats, the artery expands as it fills with blood. When the heart relaxes, the artery contracts, exerting a force that is strong enough to push the blood along.
This rhythm between the heart and the artery results in an efficient circulation system.
VEINS Transport blood at a lower pressure,
and are not as strong as arteries.
Layers are thinner, containing less tissue.
It is important that keeps blood moving in the proper direction and not be allowed to flow backward. The valves are like gates that only allow traffic to move in one direction.
Veins receive blood from the capillaries after the exchange of oxygen and carbon dioxide has taken place.
CAPILLARIES
Capillaries are very thin and fragile.
The exchange of oxygen and carbon dioxide takes place through the thin capillary wall.
The red blood cells inside the capillary release their oxygen which passes through the wall and into the surrounding tissue.
The tissue releases its waste products, like carbon dioxide, which passes through the wall and into the red blood cells. This process is called diffusion.
The heart pumps blood in two phases.
In the systolic phase, the ventricles contract, pumping blood into the arteries.
In the diastolic phase, the ventricles relax and blood flows into them from the atria.
What is Blood Pressure?
Blood pressure is the force of blood against the walls of blood vessels specifically the arteries, and is responsible for the movement of blood through the arteries.
BLOOD PRESSURE IS ESSENTIAL TO THE FLOW OF BLOOD IN EACH CIRCUIT Blood pressure accounts for the flow of blood
from the heart to the capillaries As blood flows from the aorta into the various
arteries and arterioles, blood pressure falls Blood pressure in the veins is low and cannot move
blood back to the heart, especially from the limbs Venous return depends upon three factors:
Skeletal muscle contraction, presence of valves in veins, and respiratory movements
HEART RATE AND EXERCISEIF YOU START RUNNING, YOUR BODY DEMANDS EVEN MORE OXYGEN AND THE ELIMINATION OF MORE CARBON DIOXIDE
If you start running, your body demands even more oxygen and the elimination of more carbon dioxide
As the heart beats, it presses the blood against the elastic walls of the arteries.
Each artery expands as blood is forced from the ventricles of the heart.
The artery wall then contracts to “push” the blood onward, further through the body- pulse..
How would the circulatory system respond?- raising the heart rate (how often the pump contracts) - stroke volume (how much blood the heart pumps with each
contraction).- Which increases the cardiac output (the amount of blood pumped from
the left ventricle per minute).
While you are running, blood flow is diverted toward tissues that need it most.
BLOOD VESSEL DETERIORATION RESULTS IN CARDIOVASCULAR DISEASE
In U.S., about 20% of population suffers from hypertension, high blood pressure
Heredity and lifestyle contribute to hypertensionHypertension is often seen in individuals who have atherosclerosis, which occurs when plaque protrudes into the lumen of a vessel and interferes with the flow of bloodPlaque can cause a clot to form on the irregular arterial wall
As long as the clot remains stationary, it is called a thrombus, but when and if it dislodges and moves along with the blood, it is called an embolus A stroke often occurs when a small cranial arteriole bursts or is blocked by an embolusHeart attack - when a coronary artery is completely blocked, a portion of the heart muscle dies due to lack of oxygen
CARDIOVASCULAR DISEASE CAN OFTEN BE PREVENTED
The Don’tsSmoking - When a person smokes, nicotine enters the bloodstream and causes the arterioles to constrict and the blood pressure to riseDrug Abuse - Stimulants, such as cocaine and amphetamines, can cause an irregular heartbeat and lead to heart attacks and strokesWeight Gain - in persons who are more than 20% above the recommended weight more tissues require servicing, and the heart sends the extra blood out under greater pressureThe DosHealthy Diet - Physicians advise people to replace harmful saturated fats and trans fats with healthier ones, such as monounsaturated fats (olive and canola oils) and polyunsaturated fats (corn, safflower, and soybean oils)Cholesterol Profile - Starting at age 20, all adults are advised to have their cholesterol levels tested at least every five yearsExercise - People who exercise are less apt to have cardiovascular disease
BLOODBlood travels through vessels, delivering essential
elements and removing harmful wastes.
* transporting oxygen
* carbon dioxide
* hormones
* vitamins/minerals
* ability to clot
* fight disease
Red blood cells contain a protein chemical called hemoglobin which is bright red in color.
Hemoglobin contains the element Iron, making it an excellent vehicle for transporting oxygen and carbon dioxide.
Whenever a germ or infection enters the body, the white blood cells have a variety of ways by which they can attack.
Some will produce protective antibodies that will overpower the germ. Others will surround and devour the bacteria.
White Blood cells.
* Have a sticky surface allowing them to form clots in order to stop bleeding.
* A clot begins to form when the blood is exposed to air. The platelets then form a mesh-scab.
Platelets
* Plasma is a clear liquid that is 90 percent water, and it is an essential ingredient for human survival.
* Besides water, plasma also contains dissolved salts and minerals like calcium, sodium, magnesium, and potassium.
* Microbe-fighting antibodies travel to the battlefields of disease by hitching a ride in the plasma. Without plasma, the life-giving blood cells would be left floundering without transportation.
ADULT STEM CELLS INCLUDE BLOOD STEM CELLS
A stem cell is a cell that is capable of becoming different types of cells While embryonic stem cells possess the ability to
become virtually any cell type, adult stem cells are not quite as versatile because they can become only certain other types of cell
Adult stem cells have been identified in many tissues, including the liver, skin, muscle, and even within the brain, but the richest source is in the red bone marrow Adult stem cells from bone marrow are used to treat
many white blood cell and immune system disorders, including leukemia, certain blood cancers, and anemia
Like any organ transplant, a bone marrow transplant poses the risk of rejection
HEMATOPOIETIC CELLS (ADULT STEM CELLS IN RED BONE MARROW) PRODUCE CELLS THAT BECOME THE VARIOUS TYPES OF BLOOD CELLS.
CAPILLARY EXCHANGE IS VITAL TO CELLS Capillary exchange occurs between a systemic capillary
and tissue fluid, the fluid between the body’s cells Two forces control movement of fluid through capillary wall
Blood pressure, which tends to cause water to move out of a capillary into the tissue fluid
Osmotic pressure, which tends to cause water to move from the tissue fluid into a capillary
Red blood cells and almost all plasma proteins remain in the capillaries Fluid and other substances that leave a capillary contribute
to the tissue fluid At the venous end of a capillary, blood pressure has
fallen so osmotic pressure is greater than blood pressure, and water tends to move into the capillary Some excess tissue fluid is always collected by the lymphatic
capillaries Tissue fluid contained within lymphatic vessels is called
lymph Lymph is returned to the systemic venous blood when the major
lymphatic vessels enter the subclavian veins in the shoulder region
BLOOD TYPES MUST BE MATCHED FOR TRANSFUSIONS
Presence or absence of type A and type B antigens on red blood cells determines a person’s blood typeIn the ABO system, there are four types of blood: A, B, AB, and O Type O blood has no antigens on the red blood cells
and is sometimes called the universal donor
RH SYSTEM AND ERYTHROBLASTOSIS FETALIS Rh System
Another important antigen in matching blood types is the Rh factor
85% of the U.S. population have this particular antigen on red blood cells and are called Rh-positive
Erythroblastosis Fetalis During pregnancy, if the mother is Rh-negative and
the father is Rh-positive, the child may be Rh-positive
Rh-positive red blood cells may begin leaking across the placenta into the mother’s cardiovascular system, since placental tissues normally break down before and at birth
The mother produces anti-Rh antibodies, which may cross the placenta and destroy the child’s red blood cells during a subsequent pregnancy
CONNECTING THE CONCEPTS
It is possible to relate the type of cardiovascular system to the lifestyle of an animal Some small, aquatic animals have no cardiovascular
system—external water passing in and out of a gastrovascular cavity is sufficient to meet the needs of their cells
Grasshoppers have an open circulatory system, but they utilize tracheae to deliver oxygen directly to their muscles
We traced the evolution of the two-circuit circulatory pathway in vertebrates and saw that a two-circuit pathway allows blood to pass to the lungs and to the tissues under pressure This is particularly useful in birds and mammals, which
maintain a warm body and an active way of life Body fluids make ideal culture media for the growth of
infectious parasites, and these fluids often have ways to ward off an invasion. You already know that white blood cells are involved in these endeavors