Chapter 7 The Nervous System Flashcards
Name the two divisions of the nervous system
CNS
PNS
What does the CNS stand for and what does it involve
Central nervous system
Brain and spinal cord
What does the PNS stand for and what does it involve
Peripheral nervous system
Cranial and spinal nerves
What controls the skeletal muscles
Somatic nervous system
What controls the smooth/cardiac muscle
Autonomic nervous system
What system is known as rest and digest
Parasympathetic nervous system
What system is known as fight or flight
Sympathetic nervous system
How can a neuron communicate
electrical signals
Chemical messengers = neurotransmitters
What are Glial cells
supporting cells that help neurons to function
What receives information from other neurons
dendrites
Where do action potentials generally occur
in the axons
Where do action potentials specifically occur in myelinated axons
node of ravier
What is the percentage of neurons and glial cells in the CNS
50% neurons
50% glial
Where are glial cells found and give an example
surrounding the axon and dendrites
Schwann cells (PNS)
What do Schwann cells form in the PNS
Myelin around the axon
What causes myelin to form around the CNS axon
Oligodendrocytes
What does the afferent neuron do
Takes information away from tissue and organs to the CNS
Known as sensory
What does the efferent neuron do
Take information away from the CNS to effector cells
Known as motor
What system is a muscle contraction an example of
Somatic
What does a interneuron do
Connects neurons within the CNS
What is a ganglion
Grouping of neuron cell bodies located outside the CNS
What is Ohm’s Law
I = V/R
I = Current V = electrical potential R = resistance
What is current
movement of electrical charge
What is resistance
hindrance of electrical charge movement
What is the unit of electrical potential
Volts (V)
What is the difference between Insulators and Conductors
Insulators = materials with high electrical resistance
Conductors = opposite
What is Potential difference
Difference in charge between 2 points
What is the resting membrane potential of a neuron
- 70 mV
What happens in the sodium potassium pump
3 molecules of Na move out
2 molecules of K move in
What are leak channels
always opened
What are gated channels
only open to certain substances
What happens to the membrane potential in Depolarisation
becomes less negative
From -70 to -55
What happens to the membrane potential in Hyperpolarisation
becomes more negative
Explain the steps of Depolarisation
Neurotransmitter binds to receptor
Causes Na to move into neuron making membrane potential less negative
Once it reaches threshold potential of -55 voltage gated Na channels, Na rushes in.
This causes an all or none sequence and subsequently an action potential occurs
What is repolarisation
the return to resting membrane potential
What is Ion Gating
the opening and closing of membrane ion channels due to charges/permability/polarisation
Explain the steps of Repolarisation
Membrane potential reaches +30 mV Na channels become inactive K voltage gated channels open K exits out Membrane potential becomes more negative
Explain the steps of Hyperpolarisation
Sodium potassium pump moves Na out and K in
Cl- channels open and enter neuron
This causes membrane potential to become more negative than resting
Depolarisation then occurs
What is a refractory period
Period where an action potential cannot occur
What is propagation
the one way travel of a electrical signal due to the refractory period
What is a salatory conduction
action potentials jump from one node of ranvier to another
What is a synapse
junction beween neurons or another cell
What is the difference between Presynaptic and Postsynaptic
Pre is when the neuron sends a message to another neuron
Post is when a neuron receives a message from the Pre
Name the two types of synaptic transmission
Chemical = neurotransmitter Electrical = current flow
Explain how neurotransmitters are released
Action potential reaches terminal
Voltage gated Ca channels open
Ca diffuses in and binds to sensor protein in vesicles containing the neurotransmitter
Exocytosis of vesicle occurs and the release of neurotransmitter
Graded potentials can be…
Excitatory - depolarisation through Na or Ca entry
Inhibitory - hyperpolarisation through Cl entry
Excitation can be referred to as….
EPSP = excitatory postsynaptic potential
Inhibitory can be referred to as….
IPSP = inhibitory postsynaptic potential
Name two neurotransmitters
Acetylcholine
Catecholamines
Name the two types of neurotransmitting receptors
Nicotinic receptors
Muscarinic receptors
What is involved with the Nicotinic receptor
Brain
Autonomic nervous system
Skeletal muscle fibers
What is involved with the Muscarinic receptor
Smooth muscle
cardiac muscle
some glands
Give some example of a Catecholamine
Epinephrine = adrenaline
Characteristics of catecholamines
based on tyrosine
Adrenergic neuron releases catecholamines
Adrenergic receptors
Cause mood, movement and blood pressure regulation
What is Divergence
one neuron synapses with multiple other neurons
What is Convergence
Multiple axons synapse onto a single neuron
What is Spatial summation
When signals from converging presynaptic axons summate onto a postsynaptic neuron
What is temporal summation
When multiple signals from one presynaptic axon summate onto a postsynaptic neuron
