Communication Systems Flashcards
innate immunity
defense immediately upon infection
adaptive immunity
molecular recognition and response
difference between innate and adaptive
Adaptive is acquired and enhanced by previous exposure. Innate is the same no matter previous exposure.
key cell in adaptive immunity
lymphocytes: type of WBC
types of lymphocytes
B cells and T cells
antigen
any substance that elicits response from B or T cells
antigen receptor
protein on B and T cells where they bind to antigens for recognition
antibody
soluble form of antigen receptor secreted by B cells
How do B cells recognize foreign invaders?
B cell receptors bind to the epitope of the antigen on the pathogen
How do T cells recognize foreign invaders?
T cells receptors bind to antigen fragments presented on surface of a protein called MHC molecule
Major characteristics of the immune system:
- diversity of receptors
- self tolerance
- clonal selection
- immunological memory
What is clonal selection?
an encounter with an antigen selects/dictates which lymphocyte to proliferate
humoral response
B cells eliminate pathogens in blood and lymph
cell-mediated response
T cells destroy infected host cells
helper T cells
send signal to initiate antibody production and activate T cells
cytotoxic T cells
eliminate (lyse) infected cells
plasma cell
antibody factories. antibody-secreting effector cells
What are the antibody-mediated mechanisms for antigen disposal
neutralization
opsonization
pore formation
neutralization
block ability to bind to host cells
opsonization
tag for phagocytosis
pore formation
water rushes in, cell swells and lyses
effector cells
take effect immediately against antigen
memory cells
give rise to effector cells if same antigen encountered
primary immune response
production of effector cells on first exposure
secondary immune response
faster and greater response if previous exposure
Which is faster: primary or secondary IR?
secondary
Basic function of immune system and how modes of operation carry it out
limit infection by destruction or inactivation of invaders
basic function of endocrine system
change cell activity
endocrine system
system of communication and regulation through chemical signalling by hormones
What are the two types of cellular response pathways in the endocrine system?
water soluble (polypeptides and amines) and lipid-soluble (steroids, hydrophobic)
signal transduction
series of changes in cellular proteins to convert extracellular chemical signal to intracellular response
Water soluble pathway
- hormone secreted by exocytosis
- binds to cell surface signal receptor
- triggers cascade that synthesizes cAMP, activates protein kinase, and activates an enzyme
what is cAMP also known as?
second messenger
lipid soluble pathway
- hormonediffuses out of cell
- diffuses into target and binds to intracellular receptor
- hormone-receptor complex moves into nucleus and alters transcription
negative feedback
response reduces initial stimulus to prevent excessive activity
positive feedback
response reinforces stimulus and elicits more response
antagonistic hormones
pair of negatively regulated hormone pathways that counterbalance
Explain insulin-glucagon system
control of blood glucose
- when high, insulin triggers uptake from blood to body cells to lower the concentration
- when low, glucagon promotes release of glucose into blood from energy stores to increase the concentration
Explain calcitonin-PTH system
control of Ca2+ in blood
- when high, calcitonin inhibits break down of bone matrix
- when low, PTH stimulates release from bones and absorption into blood
neurons
nerve cells that transfer info in body
nerves
bundles of neurons
cell body of neuron
directs activities
dendrites
receive messages
axons
transmit messages
Synapse
Junction where axonal terminal transmits message to next cell
Synaptic cleft
Gap between presynaptic and postsynaptic cells
Resting potential is
-70 millivolts mV
Impulse sent is called
Action potential, massive change in membrane voltage
Polarization
Potassium K+ pumped I’m through ion channels, sodium Na+ pumped out through ion channels
Forms resting potential
Depolarization
Sodium rushes back in, potential energy now positive. This change pushes the impulse through the neuron to the axonal terminals.
Threshold
When membrane voltage reaches a particular value, action potential occurs
Refractory period
Repolarization, downtime before a second action potential can be released
How is a signal conducted between neurons?
- Action potential arrives and depolarizes
- Voltage-gated channels letting in Ca2+
- Synaptic vesicles fuse with membrane and releases neurotransmitters
- Neurotransmitter binds to ion channels in postsynaptic membrane, to let sodium and potassium through
How does nervous system convey info?
Electrical signals
How do neurons speed up rate of an impulse?
Wider axons in invertebrates
Myelin sheath acts as Insulation to let current spread farther along axon
Information processing
Sensory input
Integration
Motor output
