Chap.11 Nervous Flashcards
What are the characteristics of the Nervous System
- Receives information from many sources/senses simultaneously
- Integrates Info by processing, compiling & making sense of this information
- Extremely fast (receives information, integrated it and produce responses within tenths of a second
- Initiate specific responses like muscle contraction, glandular secretion, and conscious control over thoughts, emotions, and movement.
What are the 2 types of cells in the nervous tissue?
Central Nervous System also is known as afferent
Peripheral Nervous System or efferent
What are components of the CNS
brain and spinal cord
What is the function of the CNS
Receives, process, stores and transfers information
What are the components of the PNS
All parts of the NS outside the CNS
Three major anatomical/functional divisions of the brain
Hind-brain, Mid-brain, Fore-brain
The three major parts of the brain stem are the
midbrain, pons, and medulla oblongata
The sequence in a typical reflex arc
receptor, afferent neuron, integration center, efferent neuron, effector
The neuron processes that normally receive incoming stimuli
dendrites
Sally has a brain injury; she knows what she wants to say but canʹt vocalize the words. The part of her brain that deals with the ability to speak are the
Brocaʹs area
Which of the nerves plexuses originates from ventral rami
lumbar
Which one of the following is the correct sequence in connective tissue sheaths, going from outermost to the innermost layer
epineurium, perineurium, endoneurium
Immediately after an action potential is propagated, which one of the following ions rapidly diffuses out of the cell into the tissue fluid
potassium
Which one of the following is the correct sequence of nerves that exit the spinal cord, going from superior to inferior
cervical spinal nerves, thoracic spinal nerves, lumbar spinal nerves, sacral spinal nerves
Control of temperature, endocrine activity, metabolism, and thirst are functions associated with the
hypothalamus
Preparing the body for the ʺfight-or-flightʺ response during threatening situations is the role of the
sympathetic nervous system
The gap between two communicating neurons is termed
synaptic cleft
Which of the following is a traumatic brain injury
cerebral edema
Which of the following effects is characteristic of the parasympathetic nervous system
decreases heart rate
The sympathetic and parasympathetic nervous systems are subdivisions of the
autonomic nervous system
The function of the olfactory nerve concerns
Smell
The ability to respond to a stimulus
irritability
The diffusion of potassium ions out of a neuron causes it to experience
repolarization
A neuron with a cell body located in the CNS whose primary function is connecting other neurons
association neuron
Muscles and glands are
effectors
An action potential
is essential for nerve impulse propagation
Which one of the following best describes the waxy-appearing material called myelin
a mass of white lipid material that insulates the axon of a neuron
Lobe movements: that contains the primary motor area that enables voluntary control of skeletal muscle
frontal lobe
The effects of the sympathetic nervous system are essentially opposite of the
parasympathetic nervous system
In contrast to the somatic nervous system, the autonomic nervous system
has two motor neurons
Which one of the following represents the correct sequence from outermost to innermost layers of the meninges
dura mater, arachnoid mater, pia mater
The subarachnoid space lies directly between the
arachnoid mater and pia mater
Sympathetic nervous system stimulation causes
fight-or-flight response –Increases heart rate and respiration –Raises blood pressure –Dilates pupils –Slows digestion and urine production
Which one of the following describes saltatory conduction
is faster than conduction on an unmyelinated fiber
Loss of muscle coordination results from damage to the
cerebellum
White matters refer to myelinated fibers in the
CNS
Impulse conduction is fastest in neurons that are
myelinated
An action potential is caused by an influx of these ions into the cell
sodium
The gray matter of the spinal cord
surrounds the central canal
Afferent nerves are called __________, and motor nerves are called __________
sensory nerves; efferent nerves
Which of these cells are not a type of neuroglia found in the CNS
Schwann cells
The area of the brain stem that plays a role in consciousness and the awake/sleep cycles is the
reticular activating system (RAS)
Sympathetic division fibers leave the spinal cord in the
thoracolumbar region, and the postganglionic fibers secrete norepinephrine
Which one of the following is the correct sequence of events that follows a threshold potential
2,1,4,3
sodium channels open and sodium ions diffuse inward, the membrane becomes depolarized, potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell, the membrane becomes repolarized
The vital centers for the control of visceral activities such as heart rate, breathing, blood pressure, swallowing, and vomiting are located in the
medulla oblongata
Which one of these effectors is NOT directly controlled by the autonomic nervous system
skeletal muscle
Two divisions of the PNS
Sensory and motor
What are two subunits of the Motor division
Somatic and autonomic divisions
The function of the Sensory division
carry/sends info to the CNS (brain & spinal cord)(input)
A function of the Motor division
carry/moves info away from CNS
Somatic division of the motor division
Voluntary; controlling skeletal muscle
Autonomic division of the motor division
Involuntary; controlling smooth, cardiac, and glands
Within the autonomic, there are two subdivisions, what are they?
Sympathetic (flight or fight)
Parasympathetic ( rest and digest)
Their actions oppose each other; they work antagonistically to accomplish the autonomic or maintenance of homeostasis like breathing, heart rate, etc.
What are Neurons (nerve cells)?
Excitable communication cells of the NS
Specialized single cells for communication. Neuron’s language through conducting electrical impulses (Action Potential) from one part of the body to another.
They are amitotic (Can’t divide). They also are highly metabolic in that they need an abundant amount of oxygen and glucose supply.
What are electrical impulses called
Action potentials
Three Types of Neurons
Sensory, Interneurons, Motor
Sensory neurons
Found in the PNS that receive a stimulus like pressure or light and transfer info about this stimulus to the CNS in the form of action potentials. (Provide input to the CNS)
Interneurons
Transfer info between components of CNS. They receive input from sensory neurons, integrate this info and influence function of other neurons.
Motor neuron
Found in the PNS that carry info away from CNS. They carry NS output in the form of electrical impulses (AP) to all tissues and organs of the body
Three parts of the neuron
Cell body, Dendrites, Axon
Cell Body
(soma or perikaryon): Main body, has the nucleus (DNA), surrounded by most of the cytoplasm called perikaryon which contains mitochondria, other cell organelles
Dendrites
Slender spiky branches/extensions of the cell body receive info from receptors or incoming impulses from other neurons. ***Interneurons & motor have a lot of dendrites that are short & extend many directions from cell boy but the sensory is an exception. It has dendrites that connect directly to the axon.
Axon
long, nerve fiber, slender extension tube of cell membrane contains a small amount of cytoplasm. Specialized to conduct electrical impulses away from the body.
Axons of sensory neuron
originate from dendrites
axons of motor and interneurons neurons
originate from point of union w/ cell body called axon hillock
Functions of Na+/K+ pump
Maintains cell volume
Establishes and maintains resting potential by ongoing active transport of 3 Na+ out of the cell for every 2 K+ into the cell
Resting potential
the measurable difference in voltage across the cell membrane in a resting cell
–70 mV
The concentration of K+ is higher inside the cell and the con of Na+ is higher out. The membrane is more permeable to K+ (+ outside; -inside because of proteins inside the cell which means the cell is polarized
Graded potential
Transient local changes in the resting potential
–May depolarize or hyperpolarize the membrane
Summation
May reach a “trigger point” or threshold, which initiates an action potential
What triggers the opening of the voltage?
Initiated when graded potentials reach a certain threshold (triggering point)
Depolarization
Voltage-sensitive Na+ channels open, Na moves into the axon (this reverses the voltage across the membrane, the interior becomes +)
Repolarization
Na+ channels close, K+ channels open, K+ moves out of the axon (this restores the initial polarity, actually becomes temporarily hyperpolarized)
Reestablishment of the resting potential
K+ channels close, the normal activity of the sodium-potassium pump restores resting potential
All-or-none
–Individual neuron threshold sets extent of stimulus needed
–If threshold is achieved, it triggers
–Once triggered, an action potential is always the same in speed and voltage
Self-propagating
–Continues to propagate itself in the next region of the axon
–Moves like a wave down the axon, with constant speed and amplitude
What protects and protects Neurons?
Neuroglial cells
Make up 80% of NSC (do not transmit action potential)
Two types of glial cells
–Schwann cells
–Oligodendrocytes
Schwann cells
wrap around axons of motor and sensory neurons to form myelin sheath in PNS. These myelin sheaths save the neuron energy and speed up the transmission of impulses, as well as help damaged or severed axons regenerate.
Saltatory conduction
leaping pattern of action potential conduction
Oligodendrocytes
form myelin sheath in CNS
Disorders with degenerating of the myelin sheath
Multiple sclerosis, Amyotrophic lateral sclerosis
Multiple sclerosis
Progressive damage of myelin sheath in brain and spinal. Symptoms include weakness, visual impairments, incontinence.
Amyotrophic lateral sclerosis
Progressive damage of myelin sheath in the motor area of spinal. Symptoms include weakness and wasting of skeletal muscle.
Targets
another neuron, muscle cell, or gland
Synapse
the special junction between axon terminus and target cell
Synaptic transmission
–Process of transmission of an impulse from sending (presynaptic neuron) across the synaptic cleft to receiving (postsynaptic) target
–Involves the release and diffusion of chemical neurotransmitter
Excitatory neurotransmitters
Depolarize the postsynaptic cell, approaching or exceeding the threshold
Inhibitory neurotransmitters
Hyperpolarize the postsynaptic cell
Spinal reflexes
Involuntary responses mediated primarily by spinal cord and spinal nerves, with little brain involvement
Sympathetic division
–Prepares the body for emergencies
–Norepinephrine is the key neurotransmitter
–Produces fight-or-flight response
Parasympathetic division
–Relaxes the body
–Acetylcholine is the key neurotransmitter
Parasympathetic nervous system stimulation causes
lowers heart rate and respiration, increases digestion, permits defecation and urination
Hind-Brain
coordinates basic, automatic, and movement, vital tasks
Mid-brain
coordinates muscle groups, movements, and responses to sight and sound
Fore-brain
receives, integrates sensory input, determines complex behavior (Emotions and conscious thoughts)
Bone
skull and vertebrae
Meninges
protective membranes
–Dura mater, arachnoid, and pia mater
Cerebrospinal fluid
bathes the brain, spinal cord
–Shock absorber
–Produced within the ventricles of the brain
Blood-brain barrier
prevents entry of certain chemicals and pathogens
White matter
–Outer portion of the spinal cord
–Consists of myelinated ascending (sensory) and descending (motor) nerve tracts
Spinal cord
a superhighway for action potentials between the brain and the rest of the body
Gray matter
–Center portion of spinal cord
–Contains cell bodies, dendrites
Hindbrain has three major parts
–Medulla oblongata
–Cerebellum
–Pons
Medulla oblongata
–Connects to a spinal cord
–Controls vital automatic functions of internal organs
- The crossing of motor nerves
Cardiovascular center
regulates heart rate and blood pressure
Respiratory center
adjusts respiration in response to CO2 and O2 levels
Cerebellum
–Coordinates basic body movements
–Stores and replicates sequences of skilled movements
Pons
–Connects higher brain centers and the spinal cord
–Coordinates the flow of information between the cerebellum and higher brain centers
–Aids medulla oblongata in regulating respiration
Reticular formation
group of neurons that extend through medulla oblongata, pons, and midbrain
–Works with cerebellum to control skeletal muscle activity related to posture/balance
–Maintains wakefulness
The fore-brain has 4 parts
Hypothalamus, Thalamus, Limbic system, Cerebrum
Hypothalamus
Helps regulate homeostasis
Thalamus
Receiving, processing, and transfer center
Limbic system
Pathways involved in emotions and memory
Cerebrum
Language, decision making, conscious thought
Structure of the cerebrum
–Right forebrain controls left the side of the body
–Left forebrain controls the right side of the body
which are connected by corpus callosum; allow two hemispheres to share information
Cerebral cortex
gray matter, the outer layer of the cerebrum
Functions of the Cerebral cortex
memory storage, abstract thought, conscious awareness, conscious control of skeletal muscle
The Cerebral cortex is divided into four lobes
Occipital lobe, Temporal lobe, Parietal lob, Frontal lobe
Occipital lobe
processes visual information
Temporal lobe
interprets auditory information, comprehends spoken the/written language
Parietal lob
receives and interprets sensory information from the skin
Frontal lobe
initiates motor activity, responsible for speech, conscious thought
