11.1 - NS Organization, Reflexes, Neurons Flashcards
Central Nervous System
Spinal cord and brain
What’s the nervous system divided into?
The Central NS and the Peripheral NS
Peripheral Nervous System divides into?
Motor and Sensory
Motor divides into?
Autonomic NS and Somatic NS
Autonomic Nervous System divides into?
Parasympathetic and Sympathetic NS
What do CNS and PNS control?
Sensory input, integration, and motor output
What does the central nervous system do?
It integrates and processes information sent by nerves.
Peripheral Nervous System
Includes nerves that carry sensory info to CNS, and nerves that send info to the CNS then muscles and glands.
Somatic System
Consists of sensory receptors in head and extremities, nerves carry sensory info to the CNS. Controls skeletal muscle movement.
Autonomic System
Involuntary. Controls grandiose secretions and the functioning of the smooth and cardiac muscles.
Sympathetic Nervous System
A network of nerves that helps body deal with stress situations. “Fight-or-flight”
Parasympathetic Nervous System
A network of nerves for non-stress situations. Helps run life sustaining processes, like digestion. “Rest and digest”
Neurons
The basic structural and functional units of the nervous system.
Glial Cells
Support the activity of neutrons. Found in CNS and PNS.
What do glial cells do?
Nourish the neurons, remove the wastes, maintain homeostasis, defend against infections.
Nerves
Individual neutrons are organized into tissues called nerves
What are the functions of the nervous system?
Sensory input, integration, and motor output.
Sensory input
Sensory neurons gather information from the sensory receptors (senses) and transmit these impulses to the CNS.
Integration
Interneurons only found in the CNS. They act as a link between sensory and motor neurons. They process and combine incoming sensory info, and relay outgoing motor info.
Motor Output
Motor neurons transmit info from the CNS to the muscles, glands, and other organs (effectors).
Reflexes
Sudden, involuntary responses to certain stimuli in order to protect oneself.
Reflex Arcs
Simple connections of neurons that explain reflexive behaviours.
Order of Withdrawal Reflex
Stimulus, receptor, sensory neuron, inter neuron, motor neuron, effector, response.
Interneuron
Found in your brain and spinal cord. Only in CNS. Sends messages within the CNS.
- Act as an integration center, combining information.
Sensory neuron
They take in external stimulus and send it to CNS. Found in sensory organs. Found in PNS.
Motor Neuron
Found in CNS. Send impulses/messages away from the CNS to the effectors.
What four common features do neurons share?
Dendrites, a cell body, an axon, and branching ends.
Dendrites
Short branching extensions that receive nerve impulses from many other neurons, and passes it to the cell body.
Cell body (soma)
Contains the nucleus.
Processes input from the dendrites, sends it to the axon.
Axon
Conducts impulses away from the cell body
Myelin Sheath
Fatty insulating layer that encloses the axon.
Functions of the myelin sheath?
It protects myelinated neurons and speeds the rate of nerve impulse transmission.
Schwann Cell
A type of glial cell that forms myelin sheath.
Axon terminal
The end of an axon branches into many fibers. Each terminal has a synaptic knob on it that secretes a neurotransmitter into the synapse.
Nodes of ranvier
Gaps in the myelin sheath
Function of the nodes of ranvier
Allows generation of fast electrical impulses along the axon.
What’s the nervous systems function?
- Coordinates all activities of the body.
- enables the body to respond and adapt to stimuli
Effectors
Muscles, glands, and other organs that respond to impulses from motor neurons.
Sensory receptors
Receive stimuli and form a nerve impulse
Skeletal muscles
Muscles that connect to your bones, voluntary movement.
- sensory neurons are present here
Where are sensory neurons present
Eyes, ears, and skeletal muscles
