In: Anatomy and Physiology
.1. In the resting neuron what is true about the K+ gradient?
Inside the neuron, the K+ ions will have a higher concentrations as compared to the outside.Hence making a gradient of potential across the cell membrane(-70 mV).This is by the action of membrane active transport system(Na+-K+ pump) which pumps Na+ out of the cell and K+ into it.
2. A graded potential causes large or small movements of ions?
A graded potentail is the initiial potential gradient that is created in a resting nerve dendrite terminal to make the depolarization of the membrane for the first time.The Neurotransmitter binds to the receptor of Na+ and Ca2+ and cause the opening of these channels.The Na+ and Ca2+ influx occurs to create an increased potential gradient inside the cell to make an action potential .This occurs by opening of numerous channels at a time, making a summation of all to create the action potential.Hence it is a small movevment of ions into the cell.
3. Enzymes actually change?
Enzymes lower the activation energy of reactions.This makes the reaction much faster.The activation energy is the energy required to initiate a reaction.The enzyme lowers the activation energy by binding the substrate to its active site and holding it in a way that reduces the activation energy.
4. An epidural anaesthetic is given?
A. Between spinal cord and dura mater
This space is known as epidural space.It is outside the CSF.This causes a transient loss of sensation in the certain parts of the body
5. Which brain area regulates most homestatic mechanisms?
Hypothalamus controls whole body homeostasis(Balancing of body's internal environment) by multi-endocrinal action and neural control of the organs inside the body.The pituitary control is the key action in the endocrine system.
6. Receptors will receive strong and weak stimuli. How do they respond to the different stimuli?
Stimuli bind to the receptor cell and the dendrites of the cell body recieves it.This will create a graded potential.If the signal is strong, it gives off a high frequency of action potential resulting in detection of a high intensity of the signal.If the signal is weak, ti will have only a lower frequency of action potential resulting in reading of a less intense stimuli.
7. The motor division of the PNS sends signals to?
The motor(EFFERENT) division of PNS send signal away from CNS and stimulate effector (skin,muscle,sense organs etc.) to perform a function or reflex.
8. What is a ganglion and what is its function?
Ganglion is an aggregation of soma of the neurons and glial cells.It act as a relay between the different neurological structures in the body.E.g. between PNS and CNS.,between one neuron and the other.
9. A receptor field stimulates?
The receptor field is a portion of sensory space that can induce a neuronal response upon stimulation.It can stimulte the neuronal response.
10. When a neuron reaches the membrane threshold for an action potential what happens?
When the membrane potential reaches the membrane threashold,the neuron will fire an action potential, since the threashold potential is the minimum potential that is required to elicit an action potential in a neuron.It is -55 mV for a neuron.