Penn Foster Intro to Biology Proctored Exam
The Lymphatic System
A network of lymph nodes and lymph vessels that circulate through nearly all body tissues and lymphatic
organs, drains excess fluid from tissue all over the body and transports bacteria, immune cells, and other
cellular debris (considered part of the circulatory and immune system)
Lymphatic Capillaries
Present in almost every body tissue but absent in places such as bone marrow and central nervous
system; lead to larger lymph vessels that ultimately dump recovered fluid back into circulatory system at
the base of the neck; filter foreign material (including microorganisms)
Lymphocytes
Help identify and remove microorganisms from the body; white blood cells that recognize various
antigens
Spleen
Largest lymphatic organ; filters blood rather than lymph; has a store of blood cells and replaces damaged
blood cells that pass through it
Communicable Diseases
Diseases that are caused by pathogens; can be transmitted from one person to another
Viruses
Microscopic ones are not alive, can invade host cells to replicate; can cause illnesses ranging in severity
(cold, stomach flu, HIV/AIDS, hepatitis C)
Bacteria
Trillions of beneficial _____ live in the human body which help to digest food/keep people healthy; some
pathogens which disrupt normal functioning (strep throat, meningitis, food poisoning)
Fungi
Yeast, mold, mushrooms all eukaryotes; make harder to treat with meds without affecting human cells
(ringworm, histoplasmosis, yeast infections)
Parasites
Inhabit a host + feed on host/host consumes (plasmodium, tapeworms, ticks)
Pathogens
The Lymphatic System
A network of lymph nodes and lymph vessels that circulate through nearly all body tissues and lymphatic
organs, drains excess fluid from tissue all over the body and transports bacteria, immune cells, and other
cellular debris (considered part of the circulatory and immune system)
Lymphatic Capillaries
Present in almost every body tissue but absent in places such as bone marrow and central nervous
system; lead to larger lymph vessels that ultimately dump recovered fluid back into circulatory system at
the base of the neck; filter foreign material (including microorganisms)
Lymphocytes
Help identify and remove microorganisms from the body; white blood cells that recognize various
antigens
Spleen
Largest lymphatic organ; filters blood rather than lymph; has a store of blood cells and replaces damaged
blood cells that pass through it
Communicable Diseases
Diseases that are caused by pathogens; can be transmitted from one person to another
Viruses
Microscopic ones are not alive, can invade host cells to replicate; can cause illnesses ranging in severity
(cold, stomach flu, HIV/AIDS, hepatitis C)
Bacteria
Trillions of beneficial _____ live in the human body which help to digest food/keep people healthy; some
pathogens which disrupt normal functioning (strep throat, meningitis, food poisoning)
Fungi
Yeast, mold, mushrooms all eukaryotes; make harder to treat with meds without affecting human cells
(ringworm, histoplasmosis, yeast infections)
Parasites
Inhabit a host + feed on host/host consumes (plasmodium, tapeworms, ticks)
Pathogens
