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TRANSPORT
ADAPTATIONS FOR CIRCULATION:
PROTOZOA Since protozoa are, for the most part, unicellular, all parts of the organism are in direct contact
with the environment. Most materials enter and leave the cell by diffusion. Some substances that
cannot pass through the cell membrane by diffusion enter and leave the cell by the formation of
vacuoles. Within the cell, material is distributed by diffusion and by cyclosis, the streaming of
cytoplasm.
1.
Protozoans obtain oxygen and get rid of carbon dioxide by _______________________.
2.
Streaming of cytoplasm within the ameba is called _____________________________.
HYDRA Although the hydra is multicellular and has two body layers, all the cells of the organism are
in direct contact with the environment. So there is a direct exchange of respiratory gases
between the cells and the surrounding water. Digestion in hydra begins in the gastrovascular
cavity and is finished in the cells of the endoderm. Nutrients pass from these cells to the
ectoderm cells by diffusion and active transport. Wastes can diffuse directly from the cells
into the environment.
1.
In hydra, how do the cells of the endoderm obtain oxygen and nutrients? How do they get rid
of wastes?
2.
In addition to diffusion, osmosis, and active transport, what other activities of the hydra aid in
transport?
HUMAN TRANSPORT SYSTEM:
BLOOD VESSELS –
Humans have a closed circulatory system consisting of a four-chambered heart and a highly
complex system of vessels, including arteries, veins, and capillaries.
Blood Vessels
TYPE
Arteries
Ca p illa ries
Veins
DESCRIPTION
DIAGRAM
1.
Describe the structures of arteries
2.
Do arteries carry blood toward or away from the heart? Are there any exceptions?
3.
Describe the structure of a capillary wall. How does it compare with the wall of an arteriole?
4.
Describe the exchange of materials that occur through the capillary wall.
5.
From what type of vessel does a capillary receive blood? To what type of vessel does a
capillary transport blood?
6.
Describe the structure of a vein.
7.
Do veins carry blood toward or away from the heart? Are there any exceptions?
THE HEART –
The human heart is a muscular, four chambered organ about the size of a fist. The two upper
chambers – the atria (singular, atrium) – receive blood from the body, while the two lower
chambers – the ventricles – pump blood out to the body by the force of contractions.
*** See transport diagrams handout ***
BLOOD PRESSURE –
The contractions of the muscular ventricles of the heart forces blood into the arteries, producing
blood pressure. Hypertension is a condition in which the blood pressure remains above the
accepted norm.
1.
Why is hypertension considered a potentially dangerous condition?
2.
The instrument used to measure blood pressure is called a ___________________________.
PATHWAYS OF CIRCULATION:
PULMONARY CIRCULATION –
Blood leaving the right ventricle of the heart passes through the pulmonary arteries to the lungs.
Within the capillaries of the lungs the blood gives up carbon dioxide and picks up oxygen,
returning to the left atrium of the heart. This path from the heart to the lungs and back again is the
pulmonary circulation.
*** See transport diagrams handout ***
SYSTEMIC CIRCULATION –
Blood leaving the left ventricle enters the aorta and passes from there to all parts of the body
(except the lungs), eventually returning to the heart. This is systemic circulation.
*** See transport diagrams handout ***
1.
The part of the body not served by the systemic circulation is the __________________.
COMPONENTS OF THE BLOOD:
Blood is a liquid tissue that consists of a fluid portion – the plasma – and solid components – red
blood cells, white blood cells, and platelets. The blood serves as a medium of transport, helps
protect against disease, and is involved in the regulation of body temperature.
PLASMA –
Plasma is a transparent, straw colored liquid. More than 90 percent of plasma is water. Dissolved
proteins make up another 7 percent. Plasma also transports other dissolved substances such as
nutrients, vitamins, hormones, salts, and water.
1.
What are the functions of the blood?
2. What is the function of plasma?
RED BLOOD CELLS –
Red blood cells, or erythrocytes, are disk shaped structures that are thinner in the middle than they
are around the edges. A mature human red blood cell has no nucleus. Erythrocytes are formed in
the red marrow of long bones. The main function of the red blood cells is the transport of oxygen
from the lungs to the cells of the body. To a lesser extent, they also carry carbon dioxide from the
body cells to the lungs. Red blood cells contain the respiratory pigment hemoglobin, which
greatly increases their oxygen-carrying capacity.
1.
What is the function of the red blood cells?
2.
What is hemoglobin, and what function does it serve?
3.
Where are red blood cells formed?
4. How are worn out red blood cells removed from the circulation?
5.
What is anemia?
WHITE BLOOD CELLS –
White blood cells, or leukocytes, are amebalike cells that contain a nucleus, but no pigments.
White blood cells are involved in fighting infections in the body. Several different types of white
blood cells are produced in the marrow of long bones. Lymphocytes are white blood cells that are
produced in the lymph nodes. Various types of white blood cells can pass through the walls of the
capillaries by ameboid movement and migrate to almost any tissue in the body. They fight
infection by engulfing bacteria and other microorganisms by phagocytosis. Lymphocytes also
fight infection by producing antibodies.
1.
Where are white blood cells produced?
2.
What are the functions of WBC?
3.
How do WBC engulf microorganisms?
4.
What happens to the number of WBC in the body during an infection?
PLATELETS –
Platelets are cell fragments that initiate blood clotting. These structures, which generally have no
nucleus, are formed in the marrow of long bones.
1.
What is the function of platelets?
2.
Where in the body are platelets formed?
*** See transport handout ***
BLOOD CLOTTING –
Injured blood vessels release thromboplastin, causing platelets to clump together.
Thromboplastin, with calcium ions in the blood, changes prothrombin (the inactive form of the
enzyme) to thrombin (the active enzyme). The thrombin, in turn, reacts with another blood
protein, fibrinogen, to form fibrin, which is an insoluble protein. Strands of fibrin form a
meshwork over the wound and trap blood cells. The clot dries out, forming the scab.
LYMPHATIC SYSTEM –
Lymph is a fluid that bathes all the cells of the body. It is also called intracellular fluid. Lymph
consists mainly of fluid that escapes from the blood through the walls of the capillaries. It is
similar in composition to the blood plasma. The exchange of materials between the blood and the
tissue cells takes place through the lymph.
Tiny lymphatic capillaries originate in all the tissues of the body. Lymphatic vessels are thin
walled structures that contain valves to prevent backflow. The lymph is moved through the
vessels by muscle contractions and breathing movements. Small lymph vessels merge, forming
larger and larger vessels. Eventually, all lymph passes into either the thoracic duct or the right
lymph duct. These large collecting vessels return the lymph to the circulatory system, where they
enter large veins just below the neck.
At intervals along the lymphatic vessels there are beadlike enlargements called lymph nodes, or
lymph glands. Within these structures white blood cells, some of which are produced in the
lymph nodes, remove bacteria and other foreign particles from lymph.
1.
What are the functions of lymph?
2.
Where does lymph come from?
3.
What may happen to the lymph nodes in the area of an infection in the body?
THE BLOOD AND IMMUNITY:
DEFENSES AGAINST DISEASE –
The body has three levels of defense against disease. The first includes the skin, mucus
membranes of the respiratory tract, and the hydrochloric acid of the stomach, all of which act to
prevent microorganisms from entering the body tissues. The second level of defense involves the
phagocytic white blood cells, which can migrate to the site of infection in the body and engulf the
invading microorganisms. The third level of defense involves the immunological reactions in
which antibodies are produced by the body to neutralize or destroy foreign substances.
1.
What defenses does the body have that resist entry of disease organisms?
IMMUNOLOGICAL REACTIONS –
When foreign substances enter the body tissues, they may act as antigens and stimulate certain
white blood cells to produce antibodies. Antibodies are produced in the thymus gland (in
children), lymph nodes, and spleen. Most substances that act as antigens are proteins. Each
antigen causes the production of a specific antibody, and that antibody will only react with that
particular antigen.
1.
What is an antigen?
2.
What is an antibody?
3.
Where are antibodies produced in the body?
4.
What happens in the antigen-antibody reaction?
5.
Describe the immune response in terms of “self” and “nonself.”
ACTIVE AND PASSIVE IMMUNITY –
Immunity is the body’s resistance to disease. Immunity may be present at birth (inborn)or
acquired during the life of the individual (acquired). There are two types of acquired immunity –
active and passive.
Active immunity results from actually having a disease or getting a vaccination. A vaccination is
an injection of dead or weakened antigens that cause the immune response. In both cases, you are
exposed to the antigen and your lymphocytes make antibodies. The lymphocytes start dividing
and produce special cells called memory cells. These memory cells remember that specific
antigen and live a long time, making low amounts of antibodies. Thus, whenever that antigen
invades your body again, your body attacks it immediately and you don’t get sick again. This
type of immunity is long lasting.
Passive immunity is induced by the injection into the body of antibodies produced by another
organism. This type of immunity lasts only a short time because the body does not physically
make the antibodies, thus it does not make memory cells to remember the antigen for next time.
1.
Give examples of active immunity.
2.
Give examples of passive immunity.
3.
Specify whether each of the situations listed below will lead to active or passive immunity.
a.
A boy has the mumps. ________________________
b.
An infant receives antibodies against measles in its mother’s milk.
_____________________
c.
A woman who has been exposed to hepatitis is given a shot of antibodies from
another person. ___________________
d.
4.
A child gets the polio vaccine. ___________________________
The production of antibodies against normally harmless antigens results in a condition known
as a(n) ____________________________.
BLOOD TYPES –
There are four major types of blood in humans – A, B, AB, and O. Blood type is determined by
the presence or absence of certain antigens on the surface of the red blood cells. Each blood type has
certain antibodies present in the plasma of the blood as well. The antibodies react with the antigens of the
same type causing the blood cells to clump together.
BLOOD TYPES
Blood Type
A
B
AB
O
Antigen on RBC
Antibody in Plasma
BLOOD TRANSFUSIONS OR ORGAN TRANSPLANTS
Blood Type
Can Receive From
Can Be Given To
A
B
AB
O
1.
Which blood type is the universal donor? Which type is the universal recipient?
2.
What happens if a person with type A blood if given a transfusion of type B blood?
Rh FACTOR –
The Rh factors are antigens present on the red blood cells of approximately 85% of the population
of the United States. People whose blood contains these antigens are said to be Rh –positive
(Rh+), while those whose blood lacks them are RH-negative(Rh-).
TRANSPLANTS –
Transplants involve the replacement of a diseased or injured organ or tissue with a healthy part
from another individual. The most serious problems with transplants arise because the body of the
recipient forms antibodies in response to the foreign proteins of the transplanted organ. This
immune reaction results in the rejection of the transplanted organ. Today, to some extent,
rejection may be controlled, by drugs. Transplants between identical twins are generally
successful, because their body proteins are almost identical.
1.
What causes the rejection of many skin grafts and organ transplant?
2. How can rejection of transplants be controlled?