They Lymphatic System & Body Defenses Human Anatomy & Physiology Unit 6.
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Transcript of They Lymphatic System & Body Defenses Human Anatomy & Physiology Unit 6.
They Lymphatic System & They Lymphatic System & Body DefensesBody DefensesHuman Anatomy & PhysiologyUnit 6
Lymphatic VesselsLymphatic VesselsThe function of
lymphatic vessels is to pick up the excess tissue fluid (called lymph = clear water) and return it to the blood stream
These vessels form a one-way system and only flow towards the heart
Lymph capillaries spider web through the body tissues to collected leaked fluid
Lymphatic VesselsLymphatic Vessels Like veins, lymphatic
vessels have valves to prevent the fluid from flowing backwards
While, blood stays relatively free of bacteria, viruses and cancer – they can easily enter the lymphatic vessels
This creates a problem because bacteria, viruses and cancer can then easily travel to other parts of the body
To solve this lymph nodes are throughout the body to “examine” and cleanse (if needed) by the immune system
Lymph NodesLymph Nodes They work along with
the immune system to protect the body
As the lymph is transported to the heart it makes several stops through lymph nodes to be “checked” before it reaches the heart
A collection of lymphocytes are located in lymph nodes to respond if a foreign substance is detected
This is why most of us will get swollen glands during an active infection
Lymph NodesLymph NodesMost lymph nodes are
kidney shaped and less than one inch long
There are two regions of lymph nodes in the body the right lymphatic duct and the thoracic duct
The neck and head drain into the right duct and the rest of the body goes through the thoracic duct (within these regions are thousands of lymph nodes)
Other Lymphoid OrgansOther Lymphoid Organs Spleen – helps to filter
the blood and destroy worn-out red blood cells to they can be reabsorbed by the liver
The thymus gland – functions at peak performance during youth; produces thymosin a hormone to create certain lymphocytes to heighten their protective roles
Tonsils – their job is to trap foreign pathogens before they enter the body
Body DefensesBody DefensesEvery second of
everyday hostile bacteria, viruses and fungi are trying to invade our system
There are two approaches to body defenses: nonspecific and specific defense system
Nonspecific Defense Nonspecific Defense SystemSystemThis system
responds immediately to ALL foreign substances
First line of defense is the skin, mucous membranes and secretions of the skin
The second line is phagocytic cells, antimicrobial proteins and an inflammatory response
Nonspecific Body Nonspecific Body DefensesDefenses
Examples of Surface Membrane Barriers:◦ Skin is a physical
barrier◦ Mucous membranes
line all body cavities to act as a physical barrier
◦ Vaginal secretions of adult females are very acidic
◦ The stomach produces HCl to kill pathogens
◦ Saliva can kill some pathogens
◦ Tiny hairs in the nasal cavity trap inhaled
Nonspecific Body Nonspecific Body DefensesDefenses Examples of Cells and
Chemical Defenses:◦ A fever will help increase
the rate at which defense cells work
◦ Phagocytes will engulf a foreign particle
◦ Natural killer cells will target any foreign particle and attack the cell's membrane (the cell will then shortly disintegrate)
◦ Inflammatory response will trigger redness, heat, swelling and pain The redness and heat is
caused by the increase of blood to the site, the swelling and pain is caused by the body’s attempt to prevent movement and promote healing
Specific Defense SystemSpecific Defense SystemThis is commonly
called the immune system
The most important immune cells are they lymphocytes and macrophages
A proper working immune system will protect the body from bacteria, viruses, transplanted organ or blood and even our own cells that have turned against us
Specific Body DefensesSpecific Body DefensesThe two main
types of immune cells are B-cells and t-cells
Within the B-cell family and T-cell family there are several types and each have their own job◦ Memory B-cells◦ Memory T-cells◦ Helper T-cells◦ Plasma cells◦ Suppressor T-cell
Specific Body DefensesSpecific Body Defenses Active immunity can
occur two ways naturally or artificially through immunizations
The immune system has the ability to “remember” some diseases
Passive immunity occurs when the protection is “borrowed” ◦ For example, a mother
to fetus or through breast milk (the immune system does not “remember” using passive immunity)
Disorders of ImmunityDisorders of ImmunityAllergies
◦ The body fights off a perceived threat that would otherwise be harmless (basically, the immune system overreacts)
◦ Allergies are rarely fatal; however, when the reaction enters the blood stream it circulates rapidly through the body
◦ This is call anaphylactic shock and can be fatal
Disorders of ImmunityDisorders of ImmunityImmunodeficiency
(both congenital and acquired)◦ Basically, there is
little to no immune response
◦ Severe combined immunodeficiency disease (SCID) – congenital
◦ Acquired immune deficiency syndrome (AIDS)
Disorders of ImmunityDisorders of ImmunityAutoimmune
Diseases◦ Multiple sclerosis
(MS)◦ Myasthenia gravis◦ Graves’ disease◦ Type 1 diabetes
mellitus◦ Systemic lupus
erythematosus (commonly called lupus)
◦ Rheumatoid arthritis