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IB DP Biology: HL复习笔记6.3.1 Skin
Category:
IB课程
,
教材笔记
,
福利干货
Date: 2022年7月26日 下午3:40
Skin
The
skin and mucous
membranes form a
primary defence
against pathogens that cause infectious disease
Skin
is the largest organ of the body and is covered in
microorganisms
that usually cause no issues, as they can't enter the body. Skin provides:
A
tough physical barrier
that prevents entry of
pathogens
into our bodies
Cuts in the skin are sealed by formation of
blood clots
to prevent entry of pathogens
Chemical protection
through the production of
sebum
from the sebaceous glands of the hair follicles
Sebum is a chemical responsible for maintaining a
low skin pH
which inhibits the growth of microorganisms
Mucous membranes
are found lining vulnerable areas which may be a route for pathogens into the body
This includes the
airways
, areas around the
reproductive organs
(foreskin and vagina) and the
digestive system
The membranes contain goblet cells which produce mucus containing
glycoproteins
Microorganisms and particles become
trapped
by the mucus and are then either
swallowed
(into the stomach) or
expelled
, therefore preventing infection
Mucus also contains
lysozyme enzymes
which have
antibacterial
properties, providing more protection from invading microorganisms
转载自savemyexams
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Next post: IB DP Biology: HL复习笔记6.3.2 Blood Clotting
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