13 - Neuronal Communication Flashcards
What are the 2 body systems?
Endocrine system and nervous system
Define homeostasis
coordinating the functions of organs in order to maintain a constant internal environment
What detects stimuli?
receptors
Where does a sensory neurone transmit electrical impulses?
from receptor to motor/relay/brain
Where does a motor neurone transmit electrical impulses?
from a relay/sensory to the effector
Where does a relay neurone transmit electrical impulses?
transmits impulses between neurones
Which neurones are myelinated?
motor and sensory
What makes up a myelin sheath?
Schwann cells
What do Schwann cells do?
surround axon by wrapping many times
What are the Nodes of Ranvier?
regular interruptions of myelin sheath at gaps between Schwann cells
Where can receptors be found?
skin, retina, cochlea, tongue, nose
What transduction of energy is occurring?
converting stimuli into an electrical impulse
Pacinian Corpuscles
Where are they found?
deeper in the skin in hands, feet, joints
Pacinian Corpuscles
What does it detect?
Changes in pressure
What type of channels are located in the neurone at the end of the corpuscle?
stretch-mediated sodium ion channels
What is a generator potential?
a graded change in the electrical properties of a receptor cell membrane
Is a generator potential permanent?
No it’s temporary
What causes generator potentials?
A stimulus triggers the opening of sodium ion channels that result in depolarisation of the receptor cell membrane
What is required in the membrane for ions to move across?
channels
What are voltage-gated ion channels?
are utilised for the generation and propagation of the action potentials
What are mechanically gated channels?
vibrations or pressure opens and closes these
What are ligand gated channels?
hormones and neurones modify these channels for normal cell maintenance
What is the axoplasm?
Cytoplasm of the axon
What is the resting potential of nerve impulse in mV?
-70
What is the action potential of a nerve impulse in mV?
+40
