Flashcards in CNS, PNS And Neurons Deck (36):
Why is the brain connected to the muscles and glands in the body?
So that an organism is able to respond to and act on their current environment.
What are the two major divisions of the nervous system?
The central nervous system and peripheral system nervous system.
What is the central nervous system?
A system that comprises of the brain, and the spinal cord. The spinal cord runs from the base of the brain (brain stem), inside the bones of the spine (vertebrae) to the lower middle section of the spine. It enables the the brain to communicate with the rest of the body by conveying messages from the brain to the PNS, and from the PNS to the brain.
What is the spinal cord responsible for?
As the spinal cord is segmented (divided), the upper section is responsible for communication between the brain and the upper parts of the body, and the lower section responsible for the lower parts of the body such as the legs, toes and feet.
What is the peripheral nervous system?
A system made up of two functions, which is:
- to communicate information from the body's organs, glands and muscles to the CNS, from both the outside world and inside world
- to communicate information form the CNS to the body's organs, Glands and muscles, via motor neurones
The peripheral nervous system has two subdivisions; somatic and autonomic nervous system.
What is the somatic nervous system responsible for?
The somatic nervous system is responsible for the voluntary movement of skeletal muscles. motor neurones (nerves) communicate messages from the CNS to the particular muscles that an organism intends to move at any particular moment.
In the somatic nervous system how does the CNS and PNS work together?
They work together to enable an organism to interact with the environment. For example, when a child pats a dog, the motor neurones are responsible for initiating the movement. These neurons carry information from the child's brain to the muscles in her arms and hand that allow her to move to pat the dog. Sensory neurons (nerves) convey the sensation of the dogs fur - detected by sensory receptors on the skin - to the brain. The info. would be processed as feeling soft.
What are sensory neurons?
A neuron that carries information from the body and from the outside world into the CNS
What are motor neurons?
Neurons that communicate messages from the CNS to the particular muscles that an organism intends to move at any particular moment
What is autonomic nervous system responsible for?
Responsible for the communication of information between the CNS and the body's non-skeletal muscles, as wells as the internal organs and glands that carry out the basic bodily functions necessary for survival, such as digestion and heartbeat.
What does the autonomic nervous system enable for an organism?
Due to it operating without voluntary control or conscious awareness, it enables the organism to have the cognitive resources to pay attention to other matters, such as responding to threats or other survival needs in the external environment.
What areas does the autonomic nervous system control?
It controls the function of internal organs through:
- the skin
- blood vessels
- the heart
- liver, glands, pancreas
What is the autonomic nervous system divided into?
Divided into two branches, the sympathetic nervous system and the parasympathetic nervous system
What is the sympathetic nervous system?
An emergency system that comes active when the organism perceives itself to be in danger or in times of stress. It's particular roles is to ready the body fro actions such as running away, fighting the threat, or remains frozen (freezing). A.K.A the flight, fight or freeze response
What is the parasympathetic nervous system?
Operates in circumstances where it is relatively calm. It's responsible for maintaining automatic day-to-day bodily functions such as digestion, normal heart rate and normal breathing.
this regular bodily functioning is also known as homeostasis.
How does both the parasympathetic and sympathetic nervous systems differentiate?
Both affect the same tissues and organs, but in opposite ways. The parasympathetic nervous system allows us to go about our everyday tasks and keep the body functioning in a state of balance, while the sympathetic nervous system prepares the same organs to deal with threats or stressors.
What are neurons?
They are nerve cells, responsible for communication within the body. They receive info from other neurons, process the info, then communicate it to other neurons. They basically receive, process and transmit information to each other.
They are comprised of dendrites, axons and the soma.
What are dendrites?
They look tree-like, and their function is to receive info from other neurons or sensory receptors via synapses and deliver this to the cell body or soma.
What is the soma?
The soma is the cell body. It's the largest part of the neuron and controls the metabolism and maintenance of the cell.
What is the axon?
A nerve fibre that carries info away from the soma to their ends toward other cells in contact with the neuron. This info is carried as an electrical impulses and referred to as an 'action potential'. The end of each axon has terminal buttons that secrete a neurotransmitter whenever info is sent down the axon in the form of electrical impulses.
What is a neurotransmitter?
Chemicals that help the communication across nerve synapses.
What are glial cells?
Cells that aren't part of the neuron, but help support the neuron. They act as a glue, by holding the neurons together. The four identified functions of glial cells are:
- to surround neurons and hold them in place
- supply nourishment and oxygen to neurons
- to remove dead neurons
- to insulate one neuron from another and increase the speed of transmission of nerve impulses. To this they produce myelin.
What is myelin?
A fatty substance that covers the axon to insulate it from the surrounding fluid and from other neurons. It's produced in the brain and spinal cord by glial cells. Myelinated neurons are faster in conducting messages as they move though the nervous system
What's the process of producing myelin called?
How does myelin appear And discuss role?
As segments about 1 mm long along the axons, with small gaps between segments, known as 'nodes of Ranvier'. At each node, the axon is exposed and assists with the action potential to jump from node to node at an increase conduction of speed.
Survival of an organism is dependant on how quick these messages move through the nervous system.
What are terminal buttons?
Bulb-like structures at the end of the axon which release neurotransmitters
What is between neurons?
What is a synapse?
The junction between neurons where the end of the axon, called terminal buttons of the presynaptic neuron comes into close proximity with the receptor sites on the dendrites of a postsynaptic neuron.
What is a presynaptic neuron?
The neuron before the synapse.
What is the postsynaptic neuron?
The neuron after the synapse.
What is the process of neuron communication?
Synaptic transmission. The neurons will communicate via a chemical process.
The dnedrites will firstly receive information (neurotransmitter) from the synapse, the information is passed in the form of electrical impulses through the soma along the axon, and a neurotransmitter is secreted for the terminal buttons to a synapse shared with dendrites of another neuron.
What is neural pathway?
The pathways that nerve impulses take along the neurons, which allow one part of the nervous system to communicate with another. A neural pathway can carry messages from the body to the brain (afferent pathways), from the brain to the body (efferent pathways) or within the brain itself.
What occurs at the synapse?
An electrical signal reaches the end of the presynaptic neuron, triggering the release of neurotransmitters across the gap, between the two cells. The neurotransmitter binds to a receptor on the dendrites of the postsynaptic neuron, changing the electrical charge and building towards the action potential.
What are the two possible communications between the brain and body?
- from our sense to the brain
- from our brain to our somatic nervous system
What do sensory neurons play an important role in?
In transmitting sensory information from our environment to our brain. Our ability top touch, taste, see, hear and smell all comes from a process beginning with our sensory neurons registering an external stimulus, and then relaying that information to the CNS.