Homeostasis & The Nervous System Flashcards
What is homeostasis?
The ability to maintainn a relatively stabe internal environment.
Examples of negative feedback.
body temperature, blood pressure, glucose regulation.
examples of positive feedback.
childbirth and blood clotting
what is a negative feedback loop?
a negative feedback loop is a system where the output may signal the system to stop changing.
what is a positive feedback loop?
Causes a system to change further in the same direction.
How does negative feedback work?
Any change in a system causes an action that reverses the change.
how is action potential formed?
Action potential is created when ions pass through the neuron membrane.
How is action potential transmitted?
Action potential is transmitted by traveling along the axon where it initiates the neurotransmitters.
list the five stages of the change in membrane potential.
1- Resting membrane potential
2- Threshold
3- Rising phase
4- falling phase
5- Return to Resting potential
what happens in resting membrane potential phase?
This occurs when a neuron is at its rest(-70 mv)
What happens in threshold phase?
Deporalizing stimulus arrive at the membrane making it less negative bringing it closer to threshold.
what happens in rising phase?
The deporalization enters, the voltage gated channels open allowing positive ions to enter the membrane reversing it and bring it to its most positive state.
what happens in the falling phase?
AT the peak of action potential the volatage gated channels close and the pottassium gates open allowing all possitive charged ions to leave returning it to its resting potential.
what happens in the return phase?
The membrane returns to its resting potential and the pottassium gates remain open.
what are neurotransmitters?
Chemical messangers that cross the synaptic gaps between neurons
describe the process of chemical synapse
1- Action potential arrives and presynaptic terminal.
2- Ca2+ open on presynaptic terminal
3- Synaptic vesicles release neurotransmitters
4- neurotransmitters bind to receptores on the postsynaptic neuron
5- Na+ channels open on the postsynaptic neuron.
Central nervous system
Brain - receives and processes
Spinal cord- sends signals to and from the brain.
peripheral nervous system
motor nerurons- automatic ans aomatic
sensory neurons - signals from organs to CNS
Compare autonomic and somatic nervous systems
The somativ nervous system is involved with actions that are done on purpose where the autonomic nervous system controls actions that are involuntary.
six responses for the sympathetic nervous system.
Fast heart rate, decreased bowel movement, constricted blood vessels, pupil dialation, high blood pressure, sweat
describe six responses to parasympathetic nevous system.
slow heart rate, more sliva, more bowel movements, contricted pupils, low blood pressure, slow breathing
What neurons are in the reflex arc
The nerons involved are sensory, interneurons of the spinal cors, and motor neurons connected to the spinal cord
physiology of the reflex arc
sensory neuron sends impulses to the interneuron in the spinal cord
how does the inhibition of the sodium pottassium pump affect the ability of neuron fire?
The neuron would be less excitable because the normal gradient is disrupted even if the neuron does fire the amplitude would be smaller or impaired.
