TOPIC 1.CLASSIFICATION KINGDOM FUNGI
After cells get their requirements
from tissue fluid, not all the fluid flows back into the capillaries, Part of
it flows into lymph vessels. Once in these vessels, the fluid is called lymph.
Lymph is a pale yellow fluid. It has the same components as tissue fluid, but
more fatty substances.
Lymph vessels unite to form larger
vessels called lymph ducts. There are two main lymphatic ducts; the
right lymphatic duct empties into the right subclavian vein while the
left lymphatic duct drains into the left subclavian vein. The two
veins join to form the superior vena cava. In this way, the contents of lymph
enter the blood circulation system
Formation of lymph
Lymphatic ducts form nodule-like
structures called lymph nodes. These nodes are found in the abdomen,
groin, armpits and neck. Lymph nodes are important sites for the production of
white blood cells. They also filter out foreign materials such as bacteria and
dead tissue before they enter the bloodstream.
The flow of lymph depends greatly on
the squeezing of lymph vessels by breathing movements, intestinal movements and
muscular movements. The lymph vessels have valves to prevent back flow of
lymph.
Importance of the lymphatic system
- Lymph nodes produce lymphocytes (white blood cells) which help the body to fight diseases.
- Lacteals enable absorption of fatty acids after digestion.
3.
It provides a way of getting tissue fluid back to the circulatory system.
4. The
spleen destroys worn out red blood cells.
5. The
spleen, the adenoids and the tonsils produce antibodies which help in
fighting disease-causing microorganisms
Disorders and diseases of the
lymphatic system
There are many diseases and
disorders that affect the lymphatic system. Some of these diseases and
disorders are explained below.
Elephantiasis
This is a disease that is caused by
worms (filaria) that block the lymph vessels causing accumulation of lymph
which leads to swelling of the arms or legs
Filaria worms are transmitted by
mosquitoes. Elephantiasis is treated by destroying the parasites. One way of
preventing it is by eliminating breeding areas of mosquitoes, for instance
bushes and stagnant water.
Oedema
This is the swelling of body tissues
due to excessive lymph. It is caused by increased blood pressure in the
capillaries, causing the production of large amounts of lymph that the
lymphatic system cannot transport efficiently, pregnancy, obesity and protein
deficiency.
Oedema can be controlled by taking
measures to reduce blood pressure, pregnant women keeping the feet slightly
raised when sitting or lying down eating a well-balanced diet and taking
measures to reduce body weight, for example by exercising and avoiding eating
excessive amounts of food.
Lymphoma
Lymphoma is the term used to refer
to cancers that affect the lymphatic system. These cancers cause abnormal
growth or functioning of the components of the lymphatic system. The result is
weakened immune response in the body.
Symptoms of lymphoma include swollen
and painful lymph nodes, fatigue, weight loss, night sweats and itching.
Lymphomas are treated using
chemotherapy and radiation therapy. Severe cases may call for bone marrow
transplants
Tonsillitis
This is an infection and swelling of
the tonsils. It is caused by bacteria or viruses that enter the body through the
mouth or sinuses.
Symptoms include red and swollen
tonsils, sore throat, fever or chills, muscle ache and tiredness.
Mild cases of tonsillitis are
treated by having adequate rest and taking plenty of fluids. More severe cases
may require medical treatment; frequent tonsillitis is sometimes solved by
tonsillectomy (surgical removal of the tonsils).
Summary:
- The mammalian heart is responsible for pumping blood to all parts of the body. It has four chambers: two auricles (or atria) and two ventricles.
- Valves in the heart and veins prevent the backflow of blood.
- The flow of blood in the heart is as follows
(a) Deoxygenated blood from the body
enters the right auricle through the vena cava
(b) The right auricle pumps blood to
the right ventricle.
(c) The right ventricle pumps blood
to the lungs through the pulmonary artery.
(d) Oxygenated blood from the lungs
enters the left auricle through the pulmonary vein.
(e) The left auricle pumps blood to
the left ventricle.
(f) The left ventricle pumps blood
to all parts of the body through the aorta.
4.The main blood vessels are
arteries, veins and capillaries.
5. Arteries are muscular vessels
that transport blood away from the heart. Arteries contract and relax, creating
a pulse.
6. Veins
are less muscular than arteries. They transport blood towards the heart.
7. Capillaries are very small
vessels whose walls are one cell thick. They are in direct contact with the
body tissues.
8. Blood is a fluid tissue consisting of plasma, red blood cells, white blood cells and platelets
9. Plasma is the fluid part of blood. It transports dissolved substances, helps to regulate body temperature and pH and acts as a site for the exchange of nutrients and waste products.
8. Blood is a fluid tissue consisting of plasma, red blood cells, white blood cells and platelets
9. Plasma is the fluid part of blood. It transports dissolved substances, helps to regulate body temperature and pH and acts as a site for the exchange of nutrients and waste products.
10. Red blood cells are biconcave in
shape, lack a nucleus and contain haemoglobin. Their function is to transport
oxygen and carbon dioxide.
11. White blood cells are
irregularly shaped. They are important for immunity.
12. Platelets are fragments of
cells. They help in blood clotting.
13. Grouping of human blood is done
according to the ABO system and the Rhesus factor.
14. Blood transfusion is the transfer of blood from a donor to a recipient.
15. Agglutination occurs if transfused blood is incompatible with the recipient’s blood.
16. Blood circulation is the movement of bloodfrom the heart to all parts of the body. Blood circulation in humans involves a double circulation system where there are two cycles:
- Pulmonary cycle (from the heart to the lungs and back).
- Systemic cycle (from the heart to all parts of the body and back)
17. Diseases and disorders of the human circulatory system include high blood pressure, arteriosclerosis, sickle-cell anaemia and leukaemia.
18. Blood pressure is measured by considering the pressure when the ventricles contract (systole) and the pressure when the auricles contract (diastole).
19. Lymph is formed from tissue fluid that does not flow back into the capillaries.
20. Disorders of the lymphatic system include oedema, lymphoma, tonsillitis and elephantiasis.
14. Blood transfusion is the transfer of blood from a donor to a recipient.
15. Agglutination occurs if transfused blood is incompatible with the recipient’s blood.
16. Blood circulation is the movement of bloodfrom the heart to all parts of the body. Blood circulation in humans involves a double circulation system where there are two cycles:
- Pulmonary cycle (from the heart to the lungs and back).
- Systemic cycle (from the heart to all parts of the body and back)
17. Diseases and disorders of the human circulatory system include high blood pressure, arteriosclerosis, sickle-cell anaemia and leukaemia.
18. Blood pressure is measured by considering the pressure when the ventricles contract (systole) and the pressure when the auricles contract (diastole).
19. Lymph is formed from tissue fluid that does not flow back into the capillaries.
20. Disorders of the lymphatic system include oedema, lymphoma, tonsillitis and elephantiasis.
Introduction
The transport system in plants is
not as complex as that of animals. Materials are transported by vascular
bundles made up of xylem and phloem tissues. Xylem tissue transports
water and mineral salts from the soil to all parts of the plant. Phloem tissue
transports manufactured food from the sites of photosynthesis to all parts of
the plant. In between the xylem and phloem is cambium. The cambium
divides to form newxylem and phloem
