Neurons and Homeostasis Flashcards
Action potential
is a brief electrical signal that travels along a neuron, allowing it to transmit information.
Synaptic Transmission
The process by which neurons communicate with each other at the synapse
Myelination
Speeds up the transmission of electrical signals by allowing the signal to jump between nodes of Ranvier (gaps in the myelin sheaths)
Sensory Neurons
detect stimuli (temp, heat)
Relay Neurons
transmit signals within the CNS
Motor Neurons
Carry signals to effects (muscles or glands)
Receptors
detect changes in internal/external environment
Effectors
carry out the response to bring the internal environment back to its normal state
6 stages of action potential
Resting, stimulus, Threshold, Depolarization, Depolarization, Refractory
Schwann Cells
types of glial cells that surround neurons, keeping them alive and sometimes covering them with a myelin sheath.
Excitatory effect
influx of positive ions (such as Na+) will depolarize the cell, triggering an action potential in the postsynaptic cell membrane
Inhibitory effect:
influx of negative ions will hyperpolarize the cell, preventing an action potential
Summation
Multiple presynaptic neurons form synapses with the same post synaptic cell
synapse
is the junction between two neurons where nerve signals are transmitted chemically using neurotransmitters.
Somatic Nervous System (SNS)
Controls voluntary movements (e.g., moving your arm).
Negative Feedback
A process that counteracts changes in internal conditions to restore balance
Hypothalamus
detects changes in body temperature and activates effectors to correct it
- uses sweat glands, blood vessels, and muscles to regulate it
When body temperature is too high…
vasodilation: blood vessels near the skin widen –> more heat is lost
- sweating, this evaporation cools the skin
- flat body hairs - less insulation
- Reduced metabolism - less heat is produced internally
When body temperature is too low…
Vasoconstriction: Blood vessels narrow, less heat is lost through skin
Shivering: muscles contract generating heat
Goosebumps: Hair erector muscles contract –> traps warm air for insulation
Increases metabolism
Pancreas
Releases hormone to regulate blood glucose levels
Insulin
Secreted by BETA cells in pancreas:
lowers blood glucose by increasing glucose uptake in cells and converting glucose to glycogen in the liver
Glucagon
Secreted by ALPHA cells in pancreas
Increases blood glucose by breaking down glycogen into glucose in the liver
Type 1 Diabetes
Autoimmune destruction of beta cells
no insulin production –> insulin injections
Type 2 Diabetes
Insulin resistance, Cells do not respond to insulin, blood sugar remains high
treatment: diet, exercise, medication
