DAT Integumentary and Immune Systems Flashcards
integumentary system is made up of
skin, hair, nails, glands, and some nerve
endings.
Thermoregulation skin
helps regulate
body temperature. Blood can be
shunted away from the capillaries of the
skin to reduce heat loss, hairs can be
erected (piloerection) via sympathetic
stimulation to trap insulating air next to
skin.
Protection skin
skin is a physical barrier to
abrasion, bacteria, dehydration, many
chemicals, and UV radiation
Environmental sensory input skin
skin
gathers information about the
environment by sensing temperature,
pressure, pain, and touch
Excretion skin
water and salts are excreted
through the skin, and independent of
sweating, we diffuse water out via
insensible fluid loss
Immunity skin
specialized cells of the
epidermis are components of the
immune system
Blood reservoir skin
- vessels in the dermis
hold up to 10% of the blood in a resting
adult
Vitamin D synthesis skin
UV radiation
activates skin molecules that are
precursors to vitamin D
three main layers of the
skin:
epidermis, dermis, hypodermis
Epidermis
the superficial, avascular
epithelial tissue that relies on the dermis
for oxygen and nutrients. Exposure of the
epidermis to pressure/friction will result
in thickening to form a callus.
Stratum corneum
25-30 dead
layers; filled with keratin and
surrounded by lipids. Lamellar
granules make it water repellent
Stratum lucidum
only in palms,
soles of feet, and finger tips;
consists of 3-5 layers, and appears
clear/dead
Stratum granulosum
3-5 layers of
dying cells; lamellar bodies release
hydrophobic lipids
Stratum spinous
contribute to
strength and flexibility; 8-10 layers
held together by desmosomes
which are keratin involving adhesion
proteins
Stratum basale (germinativum)
deepest layer of skin, contains
Merkel cells and stem cells that
divide to produce keratinocytes; is
attached by the basement
membrane and melanocytes are
found here
Remember the layers of the epidermis
(top to bottom) by using the mnemonic…
“Come, Let’s
Get SunBurnt!”
Keratinocytes -
produce the protein
keratin that helps waterproof the skin.
As these are pushed to the top layer
of skin, they accumulate keratin and
die, losing their organelles along the
way. Keratin is also the most
abundant protein in the epidermis
Melanocytes
- transfer skin pigment
melanin to keratinocytes
Langerhans cells
- interact with
helper T cells of the immune system
Merkel cells
attach to sensory
neurons and function in touch
sensation
Dermis
the second layer of the skin that
consists primarily of connective tissue,
collagen and elastic fibers, and contains
hair follicles, glands, nerves, and blood
vessels.
Papillary region (top 20%) dermis
thin
vascular network within upward
projecting papillae that helps supply
nutrients to epidermis and regulates
temperature. Papillae also contain
Meisner’s corpuscles (sensory touch
receptors) and their upward
projection is what creates fingerprint
ridges
Reticular region
region with dense
connective tissue, collagen, and
elastic fibers; packed with glands,
sweat gland ducts, fat, and hairfollicles; provides strength and
elasticity (stretch marks are dermal
tears)
Hypodermis (subcutaneous)
technically not a part of skin, but it is a
part of the integumentary system;
consists of areolar and adipose tissue,
and functions in fat storage, act as a
heat insulator, and serves as a shock
absorber. The hypodermis also contains
pressure sensing nerve endings and
passages for blood vessels
Sebaceous (oil) glands
glands that
are connected to hair follicles and are
absent in palms and soles. These
glands secrete oil (sebum) that keeps
skin relatively acidic to discourage
microbial growth, and acne is caused
by these glands getting clogged
Sudoriferous (sweat) glands 2 types…
Eccrine (most of body), Apocrine
Eccrine (most of body) sweat gland
regulate
temperature through perspiration
and eliminate urea; open directly
to skin
Apocrine
found in arm pits,
pubic region, and nipples;
secretions are more viscous and
open to hair follicles
Ceruminous (wax) glands
found in
ear canal and produce a wax-like
material that acts as a barrier to
entrance
Mammary (milk) glands
secrete
milk for breastfeeding
Hair
a column of keratinized cells held
tightly together, and stand up via
contraction of smooth muscles (arrector/
erector pili)
Burn degrees
a first degree burn
affects the epithelial layer, a second
degree affects the epithelial and part of
the dermal layers, and a third degree
burn affects both skin layers and
extended into the subcutaneous layer
Albumins plasma protein
transport fatty acids and
steroids, help regulate osmotic
pressure, and the most abundant
relative amounts of leukocytes in the
blood:
erythrocytes > platelets > leukocytes.
Phagocytes
engulf foreign particles,
bacteria, dead or dying cells via
phagocytosis. Macrophages are the
largest phagocytes
Neutrophils
function in destruction
of pathogens in infected tissues; are
drawn to infected/injured areas by
chemicals via the process of
chemotaxis
Monocytes
circulate in blood until
they move into tissues via
diapedesis where they develop into
macrophages, which are
professional antigen-presenting
cells that phagocytize cell debris
and pathogens. Monocytes can also
give rise to dendritic cells.
Dendritic cells
responsible for the
ingestion of pathogens and
stimulate acquired immunity. The
main role of dendritic cells is as an
antigen-presenting cell that
activates T-lymphocytes. Dendritic
cells can also have myeloid (from
monocyte) or lymphoid lineage
Eosinophils
surround and destroy multicellular
parasites.
Lymphocytes
are WBC’s, but are not
part of the non-specific second line of
defense
innate immunity,
generalized protection.
innate immunity includes…
Antimicrobial proteins, skin,Cilia, gastric juice, Symbiotic bacteria
Basophils
- release histamines for
inflammatory response, found
circulating the blood, and are recruited
into tissue when needed. Contain
histamine and heparin
Natural killer cells
other WBCs are
called natural killer cells (NK cells) and
attach abnormal body cells such as
tumors or pathogen-infected tissues
Mast cells
function in allergic response,
inflammatory response (histamine
release), and anaphylaxis. These reside in
tissues
complement system
contains ~30 complement
proteins that circulate the body and assists in
activating the immune response.
Interferons
these are secreted by cells
invaded by viruses/pathogens that
stimulate neighboring cells to produce
proteins to defend against the virus. believed to be regulators of the complement system
Inflammatory Response
series of non-specific events that occur in
response to injury or pathogens.
Histamine
is secreted by mast cells,
which are white blood cells in
connective tissue, and cause
vasodilation
Vasodilation
stimulated by histamine
and increases blood supply to the area,
which causes a subsequent increase in
temperature that stimulates WBCs that
can kill pathogens
Phagocytes
attracted to injury by
chemical gradients of the complement
system, and engulf pathogens and
damaged cells
Complement
help phagocytes engulf
foreign cells, stimulate basophils to
release histamine, and lyse foreign cells
Adaptive immunity
specific third line of
defense that develops after the body has been
attacked. attacks specific antigens not broad sweeps
Major histocompatibility complex
(MHC)
- the mechanism by which the
immune system is able to differentiate
between self and non-self. A foreign
MHC triggers a T cell attack.
Lymphocyte
primary agents of the
immune response. Are leukocytes that
originate in bone marrow and
concentrate in lymphatic tissue such as
the lymph nodes, thymus gland, and
spleen
B cells (produce antibodies)
originate
and mature in the bone marrow, and
are activated in response to antigens.
The plasma membrane of B cells
contain antigen-receptor antibodies,
the soluble form of these receptors are
antibodies (or immunoglobulins).
Antibodies
proteins that are
specific to each antigen, and have 5
classes: IgA, IgD, IgE, IgG, and IgM.
IgG
Gross - gross quantities are
produced, most abundant Ig in serum
and extravascular spaces. Can cross
placenta and are most important in
protecting the fetus
IgA
BreAst milk - found in breast milk and
other bodily secretions (most
abundant Ig in secretions)
IgM
Mono - first antibodies produced
after initial exposure to antigen
IgE
SneEze - related to allergies
IgD
Diminished - very few are produced,
and the function is not well known
Proliferation
when an antigen binds to
a B cell, proliferation (or expansion of the
B cell population) occurs, thus forming
daughter B cells.
Plasma cells
B cells that circulate in
blood and release specific free
antibodies that dispose of antigens
Memory cells
long-lived B cells
that do not release antibodies in
response to immediate antigen
invasion. Instead, they circulate the
body, proliferate, and respond
quickly (via antibody synthesis) to
eliminate subsequent invasion by
the same antigen.
T cells
originate in the bone
marrow but mature in the thymus, and
have antigen receptors yet do not make
antibodies.
Cytotoxic T cells
killer T cells that
recognize and destroy by releasing
perforin protein that punctures cells
(lysis). These can attack many cells
because they do not phagocytize
their victims.
Helper T cells
stimulate activation
of B cells, cytotoxic T cells, and
suppressor T cells. Are also the target
for the virus that causes AIDs (HIV)
Suppressor T cells
play a negative
feedback role in the immune system
Memory T cells
similar in function to
Memory B cells
Natural killer cells
attack virus-
infected cells or abnormal body cells
(tumors). These cells are part of innate
immunity, not specific, and they attack
infected body cells, not the
microorganisms directly
Clonal selection
occurs when an
antigen binds to a B cell, or when a non-
self cell binds to a T cell, and the B or T
cells divide into daughter cells that bear
a “selected” effective antigen receptor.
Responses of Acquired/Adaptive Immune
System
Cell-mediated response, Humoral Response (antibody
mediated response)
Cell-mediated response
effective
against infected cells, uses mostly T
cells and responds to any non-self cells,
including cells invaded by pathogen.
Humoral Response (antibody
mediated response)
responds to
antigens or pathogens that circulate in
lymph or blood (such as bacteria, fungi,
parasites, viruses, or blood toxins).
differences
between B and T cells
B cells can directly bind intact antigens at
their receptor sites, but T cells must have
the antigen presented as fragments from
other cells
Antibiotics
chemicals derived from
bacteria and fungi that are harmful to
other microorganisms
Inactivated vaccine
consist of
an inactivated pathogen that
has been destroyed
Attenuated vaccine
contain
live pathogens but are disabled
in some way to prevent
virulence
Toxoid vaccine
- can be made
from inactivated toxic
compounds that cause illness
rather than the pathogen itself
Passive immunity
occurs when
antibodies are transferred from another
individual
Paracrine System
consists of local
mediators that function in the immediate area
around the cell from which they were released.
These mediators can be proteins, amino acid
derivatives, or fatty acids
Prostaglandins
locally acting
autocrine/paracrine lipid messenger
molecule that has physiological effects
