Unit 8 - Cell Communication (Nervous and Endocrine) Flashcards
What are the 2 hormones in the pancreas and what do they do?
Insulin:Conversion of glucose to glycogen. Glucagon: Conversion of glycogen to glucose.
What is a chemical that can cause schizophrenia?
Dopamine
What is affected by ion concentrations across a membrane?
Electrochemical gradient
Why is homeostasis crucial to the body?
Keeps body condition steady
What neuron sends signals from the brain to muscles?
Motor neuron
When can a neuron not respond to stimuli?
When sodium is volted, causing a refractory period
How does a neurotransmitter work?
Released from a neuron to a postsynaptic cell
What hinders myelin?
Ranvier nodes
How do reflexes carry charges?
They can activate when messages are carried
What comprises myelin?
Schwann cells
How does a neuron communicate with cells?
Synapse
What hormones have a similar dynamic as insulin and glucagon?
Epinephrine and norepinephrine
How else can integration apply to cell ideas?
Integration applies to creating proteins
Why can reflexes be a bad thing?
Can be rooted and can lead to bad habits
How does inhibition reach homeostasis?
Inhibition inhibits actions, calming the body down.
Why is it important to have a resting potential?
Resting potential cools down neurons
How is blood sugar regulated?
Blood sugar levels are regulated in a negative feedback loop, which consists of the hormones insulin and glucagon.
How is blood sugar regulated?
Blood sugar levels are regulated in a negative feedback loop, which consists of the hormones insulin and glucagon.
What is a cholingeric synapse?
A cholingeric synapse is a gap where a neuron that produces acetylcholine sends messages to other neurons or skeletal muscle cells
What are the functions of the cardiovascular system?
The cardiovascular system is an organ system that allows blood to circulate and transport nutrients, hormones, oxygen, and carbon dioxide.
What is the brain and the longitudinal nerve cord a part of?
The central nervous system.
Define transducer and give and example.
A transducer is a device that receives energy from one system and transmits it to another. Glycogen phosphorylase receives information from the cell in the form of metabolic signals.
How are action potentials different from graded potentials?
Action potentials have a constant magnitude and can regenerate in adjacent regions of the membrane. Action potentials can therefore spread along axon, making them well suited for transmitting a signal over long distances.
Describe the two types of acetylcholine receptors: ionotropic and metabotropic.
Ionotropic receptors bind acetylcholine released into the synapse and open ion channels in the receiving cell’s membrane. . Metabotropic receptors function using proteins; after acetylcholine binds a receptor at a cholingeric synapse, another protein, called the second messenger, is activated. The second messenger may cause an ion channel to open, or it can induce changes in the cell itself.
What can be effective in preventing the onset of a viral infection in humans?
Getting vaccinated.
Why do graded potentials decay with distance from their source?
Graded potentials induce a small electrical current that leaks out of the neuron as it flows across the membrane.
What is the significance of ion channels?
Ion channels are pores formed by clusters of specialized proteins that span the membrane. They allow ions to diffuse back and forth across the membrane.
How are neuropeptides typically produced?
Neuropeptides, which serve as neurotransmitters that operate via metabotropic receptors, are typically produced by cleavage of much larger protein precursors.
Describe the chemical synapses.
The majority of synapses are chemical synapses, which involves the release of a chemical neurotransmitter by the presynaptic neuron.
Describe hyperpolarization in a resting neuron.
In a resting neuron, hyperpolarization results from any stimulus that increases the outflow of positive ions or the inflow of negative ions.
Describe depolarization.
A reduction in the magnitude of the membrane potential is called depolarization.
How are sodium channels affected by depolarization?
Voltage-gated ion channels are a class of transmembrane proteins that form ion channels that are activated by changes in electrical membrane potential near the channel. Because the sodium channels are voltage-gated, an increased depolarization causes more sodium channels to open, leading to an even greater flow of current (positive feedback).
Where is dopamine released from?
The hypothalamus inside the brain.
What two forces drive the diffusion of ions across a membrane?
A chemical force(ion’s conc. gradient) and electrical force(effect of the membrane potential)
What remains relatively constant when animals are acheiving homeostasis?
Animals maintain a relatively constant internal environment when the external environment changes significantly.
What is inhibition and what is the difference between competative and noncompetative inhibition?
A common way cells regulate enzyme activity; competative occurs when there is a competative inhibitor copeting with the substrate for the enzymes active site; noncompetative is when a molecule binds to the allosteric site and changes structure of the enzyme and its ability to bind to its substrate.
What releases insulin and what is its affect on the body?
It is secreted by beta cells from the pancreas and lowers blood glucose levels.
What happens during integration?
Circuits of neurons in the brain integrate the input and generate action potetials in motor neurons.
What is a motor nueron?
A nerve cell that transmits signals from the brain or spial cord to muscles or glands.
What is myelin?
A mixture of mostly lipids creating fatty electrical insulation that helps speed up nerve signals
What does dopamine affect?
Dopamine affects learning, sleep, mood and attention.
What group of neurotransmittters does dopamine belong to?
Dopamine, norepinephrine and serotonin are biogenic amines.
How is insulin regulated?
Insulin is regulated by glucose concentration in the blood.
What does the hypothalamus regulate?
It regulates homeostasis and basic survival behaviors.
In what direction do ions diffuse?
Ions diffuse down its electrochemical gradient.
What do myelin sheathes help speed up?
Nerve signals
What is an example of homeostasis relating to insulin and glucagon secretion from the pancreas?
Insulin and glucose have opposing effects that control the concentration of glucose in the blood and keep it in the normal range.
What happens during the refractory period?
a nerve or muscle is unresponsive to further stimulation.
What the resting potential and what is the relation between the sodium and potassium ions?
The resting potential is -70 mV. There are more sodium ions outside the neuron and more potassium ions inside that neuron.
What is the function of Salutatory conduction?
It increases the conduction velocity of action potentials
What is the role of Schwann cells in the nervous system?
It wraps around a nerve fiber to form the myelin sheath.
How does the sense organ respond to the external stimuli?
by conveying impulses to the sensory nervous system
What do the sensory receptors respond to?
to stimuli and transmit data about them to the brain
What role does serotonin play?
helps relay messages from one area of the brain to another
What does a stimulus do for the brain?
evokes a specific functional reaction in an organ or tissue.
How does the synapse allow a pass between the two nerve cells?
through diffusion of a neurotransmitter.
What do g-linked receptors activate and interact with?
activates a G-protein, and interacts with an ion channel or an enzyme in the membrane.
What is one example a transducer can receive energy from one system and transmit it?
Glycogen phosphorylase receives information from the cell or organism in the form of metabolic signals.
How do signal transduction get messages across?
It starts with a message and then it has a target cell
What does the phosphorylation cascade do for the cell?
It’s a phosphate group that carries energy from one chmeical group to the other
Cyclic AMP is a seconday messenger that….
spreads throughout the cell to target protein kinase
How does the ligand work if it can enter the cell?
It binds to the receptor to activate the G-proteins
