Week 5: Organization of the Nervous System and Neurophysiology Flashcards
Learning objectives:
- outline major anatomical and functional divisions of the nervous system
-define functional/structural features of a neuron
-outline functional and structural classification of neurons
What does the nervous system generally consist of?
the brain, spinal cord, nerves, ganglia existing as a complex network
What are the nerve impulses in humans called?
action potentials
What can the nervous system be divided into?
anatomically and functionally
What two anatomical divisions is the nervous system divided into
CNS, PNS
What does the PNS consist of?
cranial and spinal nerves, ganglia, nerve endings
What does the CNS consist of?
brain, spinal cord
What are the functional divisons
a) somatic, autonomic, enteric
b) sensory, motor, integrated
What kind of control does the somatic NS control?
Voluntary/conscious control eg. motor pathways and special senses
What kind of control does the ANS and ENS have?
involuntary and unconscious control
ANS eg. cardiovascular & respiratory system
ENS eg. involuntary nervous system of digestive tract, controls digestion & movement of contents
Which nervous systems communicate for motor (efferent) movement
CNS-> PNS effectors
What do PNS effectors include
skeletal, smooth and cardiac muscle and glands
Which nervous systems communicate for sensory (afferent) pathway
PNS (sensory receptors) -> CNS
What is neuroglia (glial cells)
they are non neuronal cells in the nervous system that provide structural and functional support to neurons, retains the ability to divide
What does the structure of a neuron consist of?
cell body (soma), dendrite, nucleus, axon, axon hillock,myelin coat, nodes of ranvier, axon terminals
what does a dendrite do?
they receive neural stimuli from other neurons and are excitatory/inhibitory in nature
what does the soma do?
- houses nucleus and organelles
-metabolic centre which processes and interprets stimuli
what does the axon do?
- cytoplasmic extension
- conducts nerve impulse to axon terminals so message can be relayed to effector cell
what does the axon hillock do?
it is the site of action potential initiation
What does the myelin coat do?
- insulates axon and increased the speed of action potential conduction
-different cell types provide this coating in the CNS vs PNS
What do the nodes of ranvier do
- unmyelinated segments of the axon
- impulse jumps along these down the axon
What do axon terminals do?
- AP triggers release of neurotransmitters at synapse
- To communicate with other cells/neurons
What is a dendrite?
The antennae of a neuron which receives input and information from other neurons/cells
what is a dendritic tree?
all of the dendrites belonging to one neuron
What do the receptors on dendritic membranes do?
Detect neurotransmitters in the synaptic cleft and can bind to them
What does the soma house
Organelles like mitochondria and nucleus
Why is there a lot of mitochondria in the neuron’s soma
neurons are quite lengthy hence to be able to generate enough atp to maintain the neuron
what do microtubules do
act as the main act of transport in the neuron and enable the neuron to change shape as needed
the axon is highly speicialised for?
- action potential conduction
- axoplasmic transport
What is highly specialised to support action potential conduction?
- axon hillock is the tapered part of the soma (AP initiation site)
- axon diameter/size is important to speed up the nerve impulse travelling
What is highly specialised to support axoplasmic transport?
- Specialized proteins walk vesicles up/down the axon to deliver contents
Anterograde =
towards the axon terminal (kinesin proteins)
Retrograde=
towards the soma (Dynein proteins)
What is the axon terminal?
specialised endings that make contact with the effector cells
What is the synapse?
specialised junction between a neuron-neuron and neuron-effector cell
What do axon terminals contain?
mitochondria, synaptic vesicles holding neurotransmitters
what is a synaptic cleft?
the space between pre and post synaptic membrane
outer regions of brain that are darker =
grey matter
inner whiter regions of brain =
white matter
cell bodies exist in grey matter: T or F
T
why is white matter white?
axons have myelin that travel down white matter giving it a white appearance
T or F: Neurons and nerves are the same thing
F
A nerve is a bunch of neurons: T or F
T
What are neuron classifications?
- By shape: Neurite numbers, neurite patterns
- By function
What are multipolar neurons?
- consist of 2+ dendrites surrounding cell body and one main axon
- most common neuron
- eg. motor/efferent neurons, interneurons
What are pseudo-unipolar & Unipolar neurons
- only one axon from cell body
- branches in 2 diff directions
eg. sensory/afferent neurons
