Chapter 1 Flashcards
What are the two divisions of the PNS?
Somatic Nervos System
Autonomic Nervous System
What are the four principle parts of a neuron?
Soma
Dendrite
Axon
Terminal Buttons
What is the role of a dendrite?
To receive messages/information from terminal buttons of other neurons
What does the Axon do?
Convey messages down the axon from the soma to terminal buttons
What do the Terminal Buttons do?
Forms synapses with other neurons and sends information to that nuron
Describe the key features of a multipolar neuron
1 Axon, Many dendrites
Describe key features of a bipolar
1 Axon, 1 Dendrents
Describe a Unipolar neuron
1 Axon attached to Soma; this divides, one branch receives and one branch sends information
What is contained inside the cytoplasm?
- Nucleus
- Nucleolus
- Ribosomes
- Endoplasmic Reticulum
- Golgi Apparatus
- Lysosomes
- Microtubules + Other Protein Fibers
- Mitochondria
What does the nucleolus manufacture?
Ribosomes
What are ribosomes? And where are they contained?
In the Cytoplasm; Sites for synthesis
What is endoplasmic Reticulum
Storage revisor and a channel for transportation of chemicals through the cytoplasm
What do Mitochondria do? Where are they located
Extracts energy from nutrients, located in cytoplasm
Neurons communicate by means of ______?
Synapses
When an ______ travels own an axon its _______ secrete a chemical
Action Potential; terminal buttons
Action potentials have either a _____ or a _______ effect
Excitatory; Inhibitory
Neurons receive information from the _______ of other axons from other neurons and the terminal buttons of its axon from ______ with other neurons
Terminal Buttons;Synapses
The Supporting cells of the CNS are?
Glia Cells
The supporting cells of the PNS are?
Schwann cells
A Olidodendrocye is found where?
In the CNS
What are the role of Glia?
Supporting Cells; protectors of neurons. Nerve Glue
What are the three types of Glia
Astrocytes
Oligodendrocytes
Mircoglia
Both ____ and ____ are Phagocytes
Astrocytes, Microglia
What does a phagocyte do?
Engulfs and digest phagocytes
Neurons receive most of their _____ from Astrocytes
Nutrients
What do astrocytes do with glucose?
So they brake it down to lactate, then release their into the extracellular fluid
How do Neurons get energy?
- From uptaking lactate and transporting it to Mitochondria
When is Glycogen needed?
When the metabolic rate of nearby neurons is very high
What are the three main roles of Astrocytes
- Provide and support nourishment
- Regulate composition of fluid surrounding the neuron
- Act as a Phagocyte
What is the main role of Oligodendrocytes?
To form mylin around an Axon in the CNS
What are the main roles of microglia?
Phagoctye, protects from invading microorganisms, responsible for inflammation in the case of brain damage
How do Schwann assist when there is damage to a nerve in the PNS?
help digest dead axons and arrange themselves in cylinders to guide axons regrowth
How fast does an axon grow through a Schwann cell cylinder?
3-4mm a day
How do Schwann cells differ from Glial cells?
Mylin is for only one axon, surrounding the entire axon
In damage, Schwann cells guide regrowth but Glial cells only clean up
What is the difference in the regenerating properties of axons in the CNS and PNS?
They have different characteristics of supporting cells, and the chemical compounds differ
What is the node of raniver?
Un-mylinated Segments in the Axon
Some substances can cross the BBB, others can not, this means it is ______?
Selectively Permeable
What cant substances pass easily through the BBB?
Because of endothelial cells fitting tightly together
______ May be responsible to transporting ions from the brain to the blood in the BBB
Astrocytes
What are 4 important functions of the BBB?
- Protects the brain from chemicals/foreign substances
- Protects the brain from hormones and neurotransmitters
- Maintains a constant environment
- Regulates composition of fluid
______ Molecules can NOT cross the BBB
Low Lipid (FAT) Soluable
______ soluble molecules can rapidly cross the BBB
Lipid
What does it mean if an area of the BBB is permeable?
Substances can flow through freely
What is an area in the BBB that is permeable?
The Area Postrema
The electrical charge is called the ________?
Membrane Potential
Cations have a ____ Charge?
Positive
Anions have a ____ Charge?
Negative
The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials is called ______?
Resting Potential
Reduction towards 0 of the membrane potential of a cell from its normal resting potential is called?
A reversal of itself
Depolarization
Hyperpolirzation is when….?
There is an increase in the membrane potential of a cell, relative to the normal resting potential, it overshoots the resting potential
The value of the membrane potential must be reached to produce an action potential, when this happens it is called?
Threshold of Excitation
A very rapid reversal of membrane potential is called _______?
Action Potential
An electrical charge is the result of a balance between two opposing forces
These are ______ & _______
Diffusion; Electrostatic Presusre
The ________ must be reached in order to produce an action potential
Threshold of Excitation
What is electrostatic Pressure?
The force of attraction/repulsions
The myelin Sheth is made of ___% protein, ___% Lipid
80% lipid
20% protein
A molecule that controls chemical reaction, combining two substances or breaking a substance into two parts is called a ______?
enzyme
Movement of molecules from regions of high concentration to regions of low concentration. The process where molecules distribute themselves evenly through the medium which they are dissolved in.The molecules are constantly in motion and rate of movement is proportional to temperature. - this is called ?
Diffusion
What is the Symbol for Potassium Ions
K+
What is the role of the Voltage-Dependent Ion Channel?
An ion channel that opens or closes according to the value of the membrane potential
What is the role of a sensory neuron?
to detect changes in the external or internal environment and sends information about these changes to the central nervous system (CNS).
A neuron that connect circuits of local interneurons in one region of the brain with those in other regions is called a _____ neuron?
Relay
A neuron that forms circuits with nearby neurons and analyse small pieces of information is called _____?
Local Neuron
What are the two modes of growth of axons?
- Elongate
2. Sprouting terminal buttons
Organic Anions (A-) are found in..
ONLY intracellular fluid
Chloride Ions (Cl-) ions are found in both intracellular fluid and extracellular fluid but predominantly in
Extracellular fluid
Sodium Ions (Na+) found in both intracellular and extracellular fluid but predominantly in
Extracellular fluid
____ Is the only Ion with a balanced charge and even if the membrane wasn’t there then it wouldnt move from one side to the other
Cl - Chloride Ions
The membrane is also semi permeable to ___ and ___ , and these two ions are also actively transported
Na+ Sodium and K+ Potassium
The intracelular space is full of ___ & ____ ions
Potassium K+ ions, and organic anions A-
A membranes resting potential is -70mV and when it is resting its voltage dependent sodium and potassium channels are
A) Open
or
B) Closed
Closed
Synapses can occur in three places, there are
- on dendrites
- on the soma
- on other axons