, 6.3 DEFENSE AGAINST INFECTIOUS DISEASE (ANTIBIOTIC (Inhibit the growth…
6.3 DEFENSE AGAINST INFECTIOUS DISEASE
Skin and mucous membrane
Tough outermost layer as physical barrier to stop pathogens enter
Sebaceous gland secrete sebum, which maintains skin moisture and lowers skin pH that inhibits growth of bacteria and fungi
Mucous membrane found in nasal passage and airways
trap bacteria and particles then it is expelled or swallowed
Secrete mucus that is sticky solution of glycoprotein
has antiseptic properties by the lysozyme enzyme
clotting prevent cuts from allowing mass blood loss and also avoid pathogen entry
Steps of Blood Clotting
Platelets release clotting factors
Results in the production of thrombin
thrombin turns fibrinogen to fibrin which is insoluble.
insoluble fibrin forms a mesh that traps incoming platelets and blood cells to cover the cut.
scab forms when the gel like clot meets the air
White Blood Cell
Squeeze through the pores of the capillaries to the infection site
Engulf pathogen by endocytosis
Digest them with lysozyme in their cytoplasm
When a wound is infected, large numbers of phagocytes are released, which are called pus
Antigens on the body of the bacteria is detected as foreign
Antibodies are produced specific to the antigen. The antigens stimulate cell division of the lymphocytes.
Antibodies bind to the antigen.
Some make the pathogen recognizable to phagocytes
Some prevent viruses from docking to host cells
Some of the lymphocyte stay as memory cell for future reference. Active immunity.
Inhibit the growth of microorganisms.
They block processes in prokaryotes which are not in eukaryotes
It targets the the bacterial DNA replication, transcription, translation, ribosome function, and cell wall formation.
Antibiotics does not work against viruses, only antivirals work.
Resistance to Antiobiotics
Some bacteria have evolved genes that resist antibiotics.
Due to natural selection
It is an avoidable problem if
Doctors only prescribe antibiotics for serious infections
Patients complete the whole set of antibiotics
Hospital staff maintain high standards of hygiene to prevent cross-infection
Farmers do not use antibiotics to stimulate growth
Pharmaceutical company produce new antibiotics