Chapter 2 and 3 (nervous system and stress) Flashcards
Central nervous system (CNS)
Structure- Comprised of the brain and spinal cord.
Function- receives sensory information from the peripheral nervous system and sends motor information to the peripheral nervous system.
Neurons
A cell within the nervous system that transmits messages to and from the brain.
100 billion neurons in the brain
Grow 250000 of them a minute
Neural transmission can occur at 400km/h
The longest one can be one metre in length.
The brain
Regulates and guides all other parts of the nervous system
- Vital body functions like breathing, heart rate, and digestion
- Receiving info from the outside world via senses, coordinating an appropriate response.
- Higher-order functions like planning, thinking and learning
- Emotions, personalities, sense of humour
Spinal cord
Cable-like column of nerve fibres that extends from the base of the brain to the lower back and is encased by a series of bones called vertebrae
- Two-way highway
○ SAME
○ Sensory
○ Afferent (towards brain)
○ Motor
○ Efferent (away from brain)
Peripheral Nervous System
Structure- everything outside of the central nervous system including MOG (muscles, organs, glands)
Function- sends sensory info to the central nervous system. Receives motor information from the central nervous system.
Somatic nervous system (soma means body)
Network of neurons in the body that transmit information from receptor sites to the central nervous system, and then carry information to muscles to initiate voluntary movement.
Autonomic nervous system (ANS)
A network of neurons that carry information between the central nervous system, and the organs and glands, to ensure they are regulated without conscious awareness. (respiration…)
Parasympathetic (parachute) Nervous System (PNS)
- Maintains homeostasis (regulates body function)
- Returns body to a state of calm following stress
Sympathetic Nervous System (SNS)
- Prepares body for action to deal with potential threat
- Activates fight-flight-freeze
Neural Process
- sensory (afferent neurons at receptor site feel the sensation
- pass it along afferent pathways through the peripheral nervous system and then central via the spinal cord, toward the brain.
- interneurons in the brain communicate with motor neurons
- motor neurons send a signal via efferent pathways to an effector site- the muscle
Fight-flight-freeze response
Initiated by the sympathetic nervous system and prepares the body to confront a stressful situation to optimise the chance of survival.
- Fight- stay/attack
- Flight- run
- Freeze- go unnoticed
Motor neurons
- Transmit motor information from your body to your brain
- They do this via efferent pathways (efferent means away)
Sensory neurons
- Transmit sensory information from your body to your brain
- They do this via afferent pathways (afferent means towards)
Interneurons
- Transmit information between sensory and motor neurons
- They are the most numerous neurons in the brain
- They are not found in the PNS
Spinal reflex
The body’s ability to respond and react to pain. An automatic response that is initiated by neurons in the spinal cord, independent of the brain.
- When? Pain aid survival
- How? intercepted by interneurons
- Why? Faster reaction.
Dendrite
Receives incoming neural messages
Soma
The body of the neuron, contains the nucleus with the genetic material for the neuron.
Axon
The pathway down which the neural message travels
Myelin sheath
Fatty tissue that encases the axon to aid in the speed of transmission, protects from interference
Axon terminals
Exit pathways for neural messages to make their way to the next neuron
Terminal buttons
Releases a chemical substance known as a neurotransmitter to a receiving neuron for communication purposes; also referred to as synaptic knobs.
Neurotransmission
The process of communication between neurons using electrochemical energy.
1. Neural impulse runs from dendrite to axon terminals
2. Synaptic knobs release a chemical substance
3. This neurotransmitter crosses the synapse (space from one neuron to the next)
4. The neurotransmitter is picked up by the next neuron’s dendrites.
synaptic gap
the space between the presynaptic neuron and the postsynaptic neuron