ch15 Flashcards
how many unique cell types in humans are there
abt 200
the body begins as…
one cell, a zygote
zygote
fertilized egg
differentiation
a lineage of cells becoming more specialized across generations
occurs over several rounds of stem cell division
stem cells
unspecialized cells that can turn into others
terminally differentiated
final cells cannot become another type
what are the different types of stem cells
embryonic stem cells
adult stem cells
embryonic stem cells
can become about any cell type
adult stem cells
specific cell types reside in different organs
replenish organ when cells die
can only make a certain type of cell
main cell type in the nervous sytem
neurons
sensory neurons
recieve info
motor neurons
send response out
interneurons
relay message from sensory to motor neurons
dendrites
projections that receive signals
axon
long region that message travels along
myelin sheath
coating around axon that speeds up signal
axon terminals
branches that connect to the end of next neurons
synapses
area where neurons connect
neurotransmitters
small molecules that send message to next neuron
about 60 in humans
action potential
signal sent along axon
Na+ and K+
what is the myelin sheath made up of
lipids and proteins
glial cells
support cells that take care of neurons
blood-brain barrier
brain separated from the blood by a barrier of cells
what cell type lines the blood brain barrier vessels
endothelial cells
tightly packed together
function of the blood brain barrier
prevent toxins or pathogens from entering brain
what cell makes up the pineal gland
pinealocytes
what does the pineal gland secrete
melatonin
why is the pineal gland more susceptible to blood-borne pollutants
not protected by BBB
neurogenesis
creation of new neurons
synaptogenesis
formation of new synapses/connection between neurons
neurodegeneration
death of neurons
three layers of the immune system
barrier defenses
innate immune system
adaptive immune system
what are the barrier defenses of the immune system
skin
epithelial cells
endothelial cells
barrier defenses
protect body from internalization of pathogens
innate immune system
cells that offer a GENERAL response to pathogens
adaptive immune system
cells that offer a SPECIFIC response to pathogens
hematopoietic stem cells
produced by bone marrow
differentiates into all other immune cells
granulocytes
first responders that promote inflammation
sense injury/infection and release granules
granules
group of proteins
types of granulocytes
neutrophil
basophil
eosinophil
macrophages
eat and destroy pathogens, damaged cells, or debris
natural killer cells (NK cells)
recognize infected cells and tumors
release cytotoxic molecules to kill cells
perforin function
cytotoxic molecule that pokes holes in membrane of target cell
T cells
offer SPECIALIZED recognition of foreign or damaged cells
have a T Cell Receptor on the surface that recognizes antigens
B cells
produces antibodies that surround and eat target cells
antibodies
proteins that specifically bind to a target antigen
opsonize
surround
where do T cells mature
thymus
what filters blood and stores B cells
spleen
