Introduction to the Nervous System Flashcards
In the nervous system, cells communicate by rapid, specific __________ and _____________ signals.
electrical, chemical
List and define the 3 overlapping functions of the nervous system. Think of an example of each function.
Sensory Input - Information gathered by sensory receptors about internal and external changes
Ex. Eyes
Integration - Processing and interpretation of sensory input
Motor Output - Activation of effector organs (muscles and glands) to produce a response
Ex. Muscles activated to get water
What anatomical structures make up the central nervous system?
Brain and Spinal Cord
Integration and control center
Interprets sensory input and dictates motor output based on reflexes, current conditions, and experience
What anatomical structures male up the peripheral nervous system?
Portions of the nervous system outside of the CNS - the nerves extending from the brain and the spinal cord
Spinal Nerves - to/from the spinal cord
Cranial Nerves - to/from the brain
Ganglia - collections of neuron cell bodies
What are the functions of the CNS?
Interprets sensory input and dictates motor output based on reflexes, current conditions, and experience
What are the functions of the PNS?
Communication lines that link all parts of the body to the CNS
The PNS is divided into the ___________ and ___________ divisions.
Sensory (Afferent), Motor (Efferent)
What is the function of sensory (afferent) division?
Keeps the CNS constantly informed of events going on inside and outside the body
What specific types of fibers make up the sensory division?
Somatic Sensory Fibers - convey impulses from skin, skeletal muscles, and joints to the CNS
(Responsible for voluntary movements)
Visceral Sensory Fibers - convey impulses from visceral organs to the CNS
(Responsible for involuntary movements)
What is the function of motor (efferent) division?
Transmits impulses from the CNS to the effector organs (muscles and glands)
What are the 2 divisions of the motor division of the PNS?
Somatic Nervous System
Autonomic Nervous System
Which of these is responsible for our voluntary movements? Our involuntary movements?
Somatic Nervous System (voluntary)
Autonomic Nervous System (involuntary)
What are the 2 divisions of the involuntary division (autonomic)?
Sympathetic
Parasympathetic
Which division is responsible for “rest and digest”? How about “fight or flight”?
Parasympathetic (“rest and digest”)
Sympathetic (“fight or flight”)
What are the 2 major cell types of the nervous system? What is the function of each cell type?
Neuroglia/Glial Cells - “nerve glue”; small cells that surround and wrap the delicate neurons while completing other important functions
Neurons - excitable nerve cells that respond to stimuli by changing their membrane potential and transmitting electrical signals
Which type do we have more of in terms of quantity?
There’s way more glial cells, about 10 to 50 times
List the 4 main types of neuroglia in the CNS
Astrocytes
Microglial Cells
Ependymal Cells
Oligodendrocytes
Astrocyte -
What is each type shaped like? Where could you find it?
- Shaped like sea anemones
- Cling to neurons, synaptic endings, and capillaries
Microglial Cells -
What is each type shaped like? Where could you find it?
- Small, ovoid
- Migrate towards injured neurons
Ependymal Cells -
What is each type shaped like? Where could you find it?
- Range in shape from squamous to columnar
- Line the central cavities of the brain and the spinal column
Oligodendrocytes -
What is each type shaped like? Where could you find it?
- Branched cells
- Line up along thicker nerve fibers in the CNS and wrap their processes around to form insulating myelin sheaths
Glioblastoma – the most common and aggressive type of primary brain cancer – typically develops in which type of neuroglial cell? In which lobes of the brain?
Astrocytes, frontal or temporal lobes
List the 2 major neuroglial cells in the PNS. What is each of their functions?
Myelin sheaths in the CNS are formed from _______________________.
Oligodendrocytes
Myelin sheaths in the PNS are formed from _______________________.
Schwann Cells
What is the primary function of neurons? List the 3 special characteristics of neurons on slide 15. Think about what these characteristics tell us about the function of neurons.
What are 2 functions of the cell body of a neuron?
metabolic sensor of neuron
synthesize membrane, proteins, chemicals
An arm-like structure that extends from the cell body is called a: ________________.
Dendrites
The CNS contains both ____________ and their _______________
Neuron cell bodies, processes
The PNS contains mostly just __________________
Neuron processes
Define tracts and nerves
Tracts - bundles of neuron processes in the CNS
Nerves - bundles of neuron processes in the PNS
What are the 2 types of processes?
Dendrites and axons
What is the function of dendrites? What is the functional importance of having many of them?
big surface area for receiving signals
Anatomically, where does the axon start?
Axon hillock
Branches of axons are called _________________________. The many branches at the end of axons are called _______________________.
Axon collaterals, terminals
What’s the axolemma? What is its function?
The axolemma is the cell membrane surrounding the axon of a neuron. …..
What is secreted from axon terminals? What is the function of neurotransmitters?
Neurotransmitters are secreted into the extracelluar space
Neurotransmitters can excite or inhibit the neurons, muscles, or glands they contact
- Know that things can be transported along a neuron’s axon. What are the two directions of transport? Be familiar with a couple of things that are transported in each direction – especially think about the clinical connection provided in class!
What is myelin? What is its functional importance? Are dendrites myelinated?
Many nerve fibers – especially those that are long or large in diameter are covered with myelin – a whiteish, protein-lipid substance
- Functions of Myelin:
◦ Protect and electrically insulate the axon
◦ Increase the speed of nerve impulse transmission
Dendrites are not myelinated
Define the outer collar of perinuclear cytoplasm/ neurilemma.
peripheral bulge containing the nucleus and most of cytoplasm of the Schwann cell
Do adjacent Schwann cells touch each other? What do we call the gaps between them?
Nah
The gaps are called Myelin Sheath Shells
In the CNS, regions with dense collections of unmyelinated fibers are ____________ matter.
Grey
Draw out multipolar, bipolar, and unipolar neuron structure. Which of these is the most common?
Most common is multipolar neuron
What structure are sensory neurons? Motor neurons? Interneurons
Sensory Neurons - Unipolar
Motor neurons - Multipolar
Interneuron - Multipolar
