Nervous System Flashcards
What 2 systems help keep the controlled conditions w/in the limits that maintain health and helps to maintain homeostasis
nervous system and endocrine system
what is the nervous system respsonsible for (3)
behaviors, memories, and movements
C. The study of the nervous system is _____________
neurobiology
The branch of medical science that deals with the normal functioning and disorders of the nervous system is called ____________
neurology
The nervous system carries out its coordinating task in three basic steps, what are they
- sensory/afferent function
- integrative function
- motor function
Function of: Uses sensory receptors to monitor changes occurring inside and outside the body, these are called a stimulus, the gathered info is called a sensory input
sensory/afferent function (PNS -> CNS)
function of: processes and interprets the sensory input and makes decisions about what should be done at each moment
integrative function
function of: Dictates a response by activating the effector organs, our muscles or glands, this is the response
motor function (CNS-> PNS)
E. The nervous system has two major anatomical subdivisions… what are they
central nervous system (CNS) and peripheral nervous system (PNS)
what does the CNS consist of?
brain and SC
what are the components of the peripheral nervous system
nerves and ganglions
what are bundles of fibers that act as the body’s electrical signal system, sending messages between the brain and the rest of the body
nerves
what are areas where the cell bodies of neurons are clustered
a ganglion
c. The PNS is functionally divided into ________ and ________ divisions.
sensory and motor
i. The sensory (afferent) division : conducts impulses from receptors to the ______
CNS
which division is responsible for touch, pain, pressure, vibration, temperature, and proprioception
somatic sensory division
what is special about the somatic sensory division
hearing, equilibrium, and vision
what is special about visceral sensory
taste and smell
which division is stretch, pain, temperature, chemical changes, and irritation in viscera (nausea and hunger)
visceral sensory
ii. The motor (efferent) division : conducts impulses from the ______ o the cardiac muscles, smooth muscles, and glands
CNS
which division is motor innervation to skeletal muscles
somatic motor
which division is motor innervation to smooth muscle, cardiac muscle, and glands
visceral motor
what are the 2 sub division of the visceral motor
sympathetic (mobilize system during activity) and parasympathetic (relaxes, rest)
Nerve tissue contains 2 types of cells:
neurons and glial cells
how do neurons conduct electrical signals?
transmit in the form of action potentials (AP)
what is the longevity of a neuron?
extreme longevity, function for a lifetime
Are neurons able to divide?
No
The metabolic rate of neurons is high meaning that they need constant
O and glucose
what are the 3 fundamental physiological properties that enable neurons to communicate with other cells
- excitability
- conductivity
- secretion
T or F: a. Excitability (irritability). All cells are excitable, that is, they respond to stimuli. Neurons have developed this property to the highest degree.
True
Neurons respond to stimuli by producing electrical signals that are conducted to other cells, this shows their
conductivity
When the electrical signal reaches the end of a nerve fiber, the neuron secretes a _____________ that stimulates the next cell.
neurotransmitter
a. Most neurons, or nerve cells, consist of a cell body (soma), and neuron processes that extend from the cell bodies: many dendrites, and usually a single _______
axon
lipofuscin, chromatophilic substances (nissl bodies), and neurofibrils are all part of the ______ _______
cell body
Lipofuscin : a brownish pigment that accumulates in cells over time and is also known as the _______ pigment
aging
Chromatophilic substances (Nissl bodies) : large clusters of rough ER and free ribosomes that stain _______
darkly
iii. Neurofibrils : __________ filaments (run like a network) between chromatophilic substance)
intermediate
_______ neuron cell bodies are located within the CNS, however, some clusters of cell bodies (ganglia) lie along the nerves of the PNS.
Most
The ______ are branched receptive sites, conduct electrical signals toward the cell body
dendrites
the ______ are impulse generators and conductors that transmit nerve impulses AWAY from their cell body
axons
Do most axons branch extensively at their distal end
yes
thick insulating covering that prevent leakage of current and increase the speed of impulse
myelin sheath
iii. Mot neurotransmitters : excite or inhibit the neuron or target organ that are in close contact
motor neurotransmitters
what are known as knobs and are involved in neurotransmitter release
axon terminals
e. The site of functional contact between two neurons or between a neuron and an effector cell is called a _________
synapse
Neurons fall into three functional classes based on the three major aspects of nervous system function
- sensory (afferent) neurons
- interneurons
- motor (efferent) neurons
make up the sensory division of the PNS (PNS -> CNS)
sensory (afferent) neurons
lie in between motor and sensory neurons. They are multipolar neurons that are confined in the CNS
interneurons
carry impulses away from the CNS to effector organs (CNS -> PNS)
Motor (efferent) neurons
what can you use to remember nuerons?
SAME
classification of neurons: have more than two processes
multipolar
classification of neurons: have two processes that extend from opposite sides of the cell body
Bipolar neuron
classification of neurons: have a short, single process that emerges from the cell body like an inverted T
unipolar neurons
are specialized tissue cells that support neurons, attach neurons to blood vessels, produce the myelin sheath around axons, and carry out phagocytosis.
neuroglia
can glia cells divide? How might this be bad?
Cells can divide - rapid mitosis in tumor formation (gliomas).
What are the 4 cell types of CNS
astrocytes, oligodendrocytes, microglia, ependymal
CNS: most abundant CNS neurolglia
astrocytes
CNS: have processes that form myelin shealths around long axons of the CNS
oligodendrocytes
CNS: defensive cells in the CNS
microglia
CNS: line cerebrospinal fluid-filled cavities
ependymal
what are the 2 main types of PNS cells
Schwann and satellite cells
PNS: surround all axons in the PNS and form myelin sheaths around many of these axons
Schwann cells
PNS: protective function for PNS fibers
neurolemma
PNS: formed by schwann cells
Myelin Sheaths in PNS
PNS: myelin sheath gaps allowing impulses to jump
nodes of ranvier
PNS: surround neuron cell bodies w/ ganglia (provide support)
satellite cells
Clusters of cell bodies include:
a. Ganglia : Found in the ____
b. Nuclei : Found in the ______
PNS, CNS
collection of axons in the PNS
Axons
groups of _______ are bound into bundles called nerve fascicles
axons
describe the 3 layers of a nerve (similar to muscle tissue)
- endoneurium. Covering the schawann cells
- Perineurium : wrapping over nerve fascicles
- epineurium : surrounds whole nerve with tough fibrous sheath
White matter is composed of
myelin sheaths
Gray Matter is composed of
neuron cell bodies are clustered
what are 3 ways plasticity is maintained throughout life (nerve)
- sprouting of new dendrites
- synthesis of new proteins
- changes in synaptic contacts with other neurons
Is there a limited ability for regeneration?
Yes
Are repairs possible in the CNS?
No
Under what conditions can the PNS repair damaged dendrites or axons
- Neuron cell body remains intact
- Schwann cells remain active and form a tube
- Scar tissue does not form too rapidly.
A. the _______ ________ serves as an integrating center for spinal reflexes
spinal cord
A _______ is an automatic response to a stimulus
reflex
T or F: Reflexes may be spinal and cranial in location, and somatic, or autonomic in function. and can even include glandular secretion
true
what are learned responses called
conditioned reflexes
T or F: A reflex arc is the simplest type of pathway; pathways are specific neuronal circuits and thus include at least one synapse.
True
T or F: The five functional components of a reflex arc are the receptor, sensory neuron, integrating center neuron, motor neuron, and effector.
True
_________ spinal reflexes include the stretch reflex, tendon reflex, flexor (withdrawal) reflex, and crossed extensor reflex; all exhibit reciprocal innervation
somatic
what is an example of a stretch reflex
Tendon Reflex : neural response when a muscle is tapped, causing the muscle to contract (Ie knee tap)
________ reflex is a protective response that causes a limb to suddenly pull away from a harmful stimulus, such as heat or pain (ie touching the stove)
withdrawal
A reflex action of the toes, normal during infancy but abnormal after 12 to 18 months of age; after locomotion begins, it is indicative of abnormalities in the motor control pathways leading from the cerebral cortex and is widely used as a diagnostic aid in disorders of the central nervous system. It is elicited by a firm stimulus (usually scraping) on the sole of the foot, which results in dorsiflexion of the great toe and fanning of the smaller toes. Normally such a stimulus causes all the toes to bend downward. This is called the
Babinski reflex
