1 Neurons and Synapse Flashcards
The two divisions of the nervous system. (Controls movements)
- Central Nervous System
- Peripheral Nervous System
Central Nervous System is what?
The central nervous system (CNS) is made up of the brain and spinal cord.
Peripheral Nervous System is what?
Sends Information to muscles. Nerves branch out from the spinal cord.
These nerves form the communication network between the CNS and the body parts.
The peripheral Nervous System can be divided into the (two)…
- Somatic Nervous System
- Autonomic Nervous System
The Somatic Nervous system is…
The somatic nervous system is a component of the peripheral nervous system associated with the voluntary control of body movements via the use of skeletal muscles (the portion that interacts with the external environment.
Autonomic Nervous System
The autonomic nervous system is a component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal. It contains three anatomically distinct divisions: sympathetic, parasympathetic, and enteric
What are Afferent Nervous
Afferent neurons, also called sensory neurons, are the nerve fibers responsible for bringing sensory information from the outside world into the brain. Sensory information may involve special senses, such as vision, hearing, smell, or taste, as well as the sense of touch, pain, and temperature.
What are Efferent Nerves?
Efferent neurons, also called motor neurons, are the nerve fibers responsible for carrying signals from the brain to the peripheral nervous system in order to initiate an action. In other words, they are the neurons that tell your body to perform an action, such as removing your hand from a hot pan.
Efferent Nerves can be split into…
- Parasympathetic Nervous System
- Sympathetic Nervous ssytem
Parasympathetic nervous systmem…
Your parasympathetic nervous system is a network of nerves that relaxes your body after periods of stress or danger. It also helps run life-sustaining processes, like digestion, during times when you feel safe and relaxed.
Sympathetic nervous system
Your sympathetic nervous system is a network of nerves that helps your body activate its “fight-or-flight” response. This system’s activity increases when you’re stressed, in danger or physically active
How many Cranial nerves are there? And what are they?
- Smell
- Vision
- Eye movement
- Trigeminal (facial sensation, mastication)
- Facial Expression
- Hearing and balance
- Oral sensation, taste, salvation
- Vagus (heart, lungs, digestion)
- Shoulder elevation and head-turning.
- Tongue movement
How many spinal nerves are there? What are its sections?
Cervical, C1-C8.
Thoracic, T1-T12
Lumbar, L1-L5
Sacral, S1-S5
Coccygeal
Cross Section of the Spinal Cord
input (blue)
Output (red)
Divisions of the Adult Human Brain
- Forebrain: Telencephalon, Diencephalon
- Midbrain: Mesencephalon
- Hindbrain: Metencephalon, Myelencephalon
How many layers of the neocortex are there?
6
Major External Features of a Neuron
- Dendrites
- Cell Body
- Cell membrane
- Axon hillock
- Axon
- Myelin
- Nodes of Ranvier (gapes between myelin)
- Synapse
How much is a resting neuron charged too?
-70mV
Ion concentration of resting neuron
Inside,
- K+ = Potassium
- A- = protiens
Outside the neuron
- Na+ = sodium
- Cl = Chloride
Is the outside of a neuron positively or negatively charged?
Positive
What is depolarisation of a neruon?
movement of a cell’s membrane potential to a more positive value (i.e. movement closer to zero from resting membrane potential). When a neuron is depolarized, it is more likely to fire an action potential
Potassium allows for repolarisation.
How can ion channels be opened or closed?
By receptor activation. e.g. signalling molecule or an environmental event (light sound, touch).
EPSP (Excitatory post-synaptic potential)
- (sodium ion flow inward is responsible for generating of an EPSP.
What is an action potential?
Velocity of action potential (0.5-2.0 m/s)
An action potential occurs when a neuron sends information down an axon, away from the cell body. Neuroscientists use other words, such as a “spike” or an “impulse” for the action potential. The action potential is an explosion of electrical activity that is created by a depolarizing current. They are larger in size and shorter lasting.
What is the Hodgkin-Huxley cycle?
Synaptic potential….
Depolarisation of membrane –> Opening of violated- gated Na+ Channels –> Na+ flows into neruon –>
Discovered in a squid.
What does Myelin do?
Speeds up the actional potential propogation. Can get to up to 100m per second.
Multiple Sclerosis is due too?
Demyelination: where they break down can make it so your nervous system cant send action potentials which results in slurred speech
