Finals: Exam 2 Review Flashcards
Muscle fibers are similar to other cells except are
a. Multinucleate and striated
Includes the single synaptic ending of the motor neuron innervating each muscle fiber and underlying specialization of sarcolemma
a. Neuromuscular junction NMJ
Place on sarcolemma where NMJ occurs
a. Motor end plate
Includes each motor neuron and all fibers it innervates
a. Motor unit
T or f When a motor neuron is activated, all muscle fibers in its motor unit contract
a. True
Fine movement occur when
a. Motor units are small
Gross movement occur when motor units are
a. Large
Since individual motor units fire “ all or none” how do skeletal muscles perform smooth movements
a. Recruitment
_____ are composed of thick and thin filaments that give rise to bands which underlie striations
a. Myofilaments
Muscle contracts because myofibrils get shorter and it Occurs because thin filaments slide over and between thick filaments
a. Sliding filament theory of contraction
After binding myosin undergoes conformational change ____ (thin slide over thick filament) which exerts force on actin
a. Power stroke
Cross bridges are formed by
a. Heads of myosin
Control of cross bridge attachment to actin is via _______ which serves as a switch for muscle contraction and relaxation
a. Troponin-tropomyosin system
Ca2+ levels decrease because it is continuously pumped back into _______ (a calcium reservoir in muscle)
a. Sarcoplasmic reticulum
Release of Ach at NMJ causes
a. Large depolarizing end-plate potentials and Aps in muscle
Ca++ channels in SR are mechanically channels on T tubules an dAPs in T tubules cause release of Ca++ from cisternae via V-gated Ca++ release channels called
a. Electromechanical release
Single rapid contraction and relaxation of muscle fibers
a. Twitch
If 2nd stimulus occurs before muscle relaxes from 1st, the 2nd twitch will be greater
a. Summation
If muscle is stimulated by an increasing frequency of electrical shocks, its tension will increase to a maximum
a. Incomplete tetanus
If frequency is so fast no relaxation occurs, a smooth sustained contraction result
a. Complete tetanus
If muscle is repeatedly stimulated with maximum voltage to produce individual twitches , successive twitches get larger
a. Treppe or staircase effect
Largest part of brain (80 % mass) and is responsible for higher mental functions
a. Cerebrum
Each hemisphere of cerebrum has 5 lobes
a. Frontal
b. parietal
c. temporal
d. occipital
e. insula
Outermost portion of cerebrum with numerous folds and grooves = convolutions
a. Cerebral cortex
An elevated fold is called
a. Gyrus
Frontal lobe is separated from parietal lobe by a deep fissure called
a. Central sulcus
_____ of frontal lobe is involved in motor control
a. Precentral gyrus
_____ of parietal lobe receives sensory info from areas controlled by precentral gyrus
a. Postcentral gyrus
Contains auditory centers; receives sensory info from cochlea and also links and processes auditory and visual info
a. Temporal lobe
Responsible for vision and coordination of eye movement
a. Occipital lobe
Plays role in memory encoding; integrates sensory info with visceral responses; coordinates cardiovascular response to stress
a. Insula
involves complex computer manipulation obtained from x-ray absorption of tissues of different densities; visualizes soft tissues at different depths
a. x-ray computed tomography CT
uses radioisotopes that emit positrons injected into the blood stream; positrons collide with electrons causing the emission of gamma rays that can be detected and indicate the most active areas of the brain; is used to examine brain metabolism & blood flow, drug distribution (allows to see blood flow in brain)
a. Positron-emission tomography PET
protons (H+) can be controlled by magnetic fields and emit detectable radio-wave signals when stimulated; shows brain function
a. Magnetic resonance imaging MRI
Measures electrical activity of cerebral cortex; used to diagnose epilepsy & brain death (least dangerous)
a. Electroencephalogram EEG)
Ability to remember facts and events
a. Declarative memory
Perceptual and motor skills
a. Nondeclarative memory
The consolidation of S-T into L-T memory is the function of the _______ = hippocampus, amygdaloid nucleus, and adjacent areas of cerebral cortex
a. Medial temporal lobe (MTL)
Is critical for acquiring new memories and consolidating short-into long-term memory
a. Hippocampus
Crucial for fear memories
a. Amygdala
Removal of the left MTL impairs the consolidation of
a. Short term verbal memories
Increased sustained excitability of a synapse after initial high frequency stimulation
a. Long term potential LTP
Hippocampus contains neural stem cells that may produce new neurons
a. Neurogenesis
Stress or depression impede learning and cause
a. Hippocampus to shrink
Contains several nuclei of cranial nerves and 2 important respiratory control centers = apneustic and pneumotaxic
a. Pons
2nd larges structure in brain; receives input from proprioceptors; involved in coordinating movements and motor learning
a. Cerebellum
Contains all tract that pass between brain and spinal cord, many nuclei of cranial nerves, and several curual centers for breathing and cardiovascular system
a. Medulla
Complex network of nuclei and fibers spanning medulla, pons, midbrain, and thalamus, and hypothalamus; functions as reticular activating system
a. Reticular formation
Sets level of arousal of cerebral cortex to incoming sensory information
a. Reticular formation
Manages our physiology by regulating cardiac and smooth muscles and glands that are not under voluntary control
a. Autonomic nervous system
Neurons that conduct impulses away from CNS
a. Motor efferent
Have cell bodies in CNS and send axons to skeletal muscle for voluntary control (sensory neuron CNS motor output neurons effector organ)
a. Somatic pathway
(sensory neuron –> CNS –> preganglionic neuron –> postganglionic neuron –> effector organ)
a. Autonomic pathway
Without innervation skeletal muscle is
a. Paralyzed
Smooth muscle and cardiac muscle maintain resting tone in absence of nerve stimulation; becomes move sensitive when ANS input is cut
a. Denervation hypersensitivity
Originate in the spinal cord between thoracic and lumbar levels
a. Preganglionic fibers of sympathetic division
Mediates “fight, flight, and stress” reactions mostly trough the release of norepinephrine from postganglionic fibers and epinephrine from the adrenal medulla
a. Sympathetic division
Originate in the brain and in the sacral levels of the spinal cord
a. Preganglionic fibers of parasympathetic division
Mediates “rest and digest” reactions through the release of Ach from postganglionic fibers
a. Parasympathetic division
Sympathetic division of the ANS is also called _____ because its preganglionic neurons exit spinal cord from t1 to L2
a. Thoracolumbar division
Most sympathetic fibers separate from somatic motor neurons and synapse on postganglionic neurons within a double row of ganglia called
a. Paravertebral ganglia
Paravertebral ganglia Form chain of interconnected ganglia paralleling spinal cord called the
a. Sympathetic chain of ganglia
Myelinated preganglionic sympathetic axons exit the spinal cord in the ventral roots of spinal nerves but diverge within short pathways called
a. White rami communicantes
Axons of postganglionic neurons are unmyelinated and from the _____ as they return to spinal nerves
a. Gray rami communicantes
Divergence and convergence together cause the sympathetic division to mostly act as a unit
a. Mass activation
Outer adrenal glands secrete
a. Steroid hormones
Inner adrenal medulla secretes
a. Mostly 85% epinephrine (adrenaline) and norepinephrine (15%)
_____ appears to be a modified sympathetic ganglion because it has the same embryonic origin as the postganglionic sympathetic neurons
a. Adrenal medulla
Parasympathetic division of the ANS is also called ______ because long preganglionic parasympathetic fibers originate in midbrain, medulla, pons and 2nd – 4th region of spinal column
a. Craniosacral division
Preganglionic parasympathetic fibers synapse on postganglionic parasympathetic fibers in parasympathetic ganglia called _______ located next to or within target organ
a. Terminal ganglia
Cutaneous effectors (sweat glands, blood vessels, arrector pili receive
a. Sympathetic innervation
The _______ carries most parasympathetic fibers and synapse in terminal ganglia spread throughout the body (innervates heart, lungs, esophagus, stomach, pancreas, liver, small intestine and and upper half of the large intestine)
a. long vagus nerve X
parasympathetic postganglionic fibers also release Ach called
a. cholinergic synapses
Most postganglionic sympathetic fibers release norepinephrine (noradrenaline) called
a. Adrenergic synapse
Where postganglionic autonomic neurons enter into their target organs, they have many swellings called varicosities which release NTs along a length of axon that forms unusual synapse called
a. Synapses en passant
Drugs that promote actions of a NT
a. Agonist
- Drugs that inhibit actions of a NT
a. Antagonist
Are stimulated by nicotine and Ach and are always excitatory; located in NMJs and autonomic ganglia
a. Nicotinic receptors
Stimulated by Ach and muscarine and can be excitatory or inhibitory
a. Muscarinic receptors
Some postganglionic neurons Appear to use ATP, VIP and NO and do not use norepinephrine or Ach
a. Nonadrenergic noncholinergic fibers
Cause similar effects such as with salivation
a. Complementary
Produce different effects that work together to cause desired effect…eg reproductive system
a. Cooperative or synergistic
Adrenal medulla, arrector pili muscle, sweat glands, and most blood vessels receive only
a. Sympathetic innervation
Most directly controls activity of ANS by receiving afferent information via CNX (vagus)
a. Medulla oblongata
Has centers for control of cardiovascular, pulmonary, urinary, reproductive, and digestive systems
a. Medulla oblongata
Has centers for control of body temperature, hunger, thirst, the pituitary gland, the cerebral cortex and limbic system (emotions), and can regulate medulla oblongata
a. Hypothalamus
Is responsible for visceral responses that reflect emotional states
a. Limbic system
Transduce (change) environmental information into Aps
a. Sensory receptors
Sense chemical stimuli (taste buds, olfactory receptors)
a. Chemoreceptors
Transduce light (rods and cones)
a. Photoreceptors
Respond to temperature changes (heat and cold)
a. Thermoreceptors
Respond to deformation of their cell membrane (touch, pressure, hair cells of inner ear)
a. Mechanoreceptors
Respond to intense stimuli by signaling pain
a. Nociceptor
Signal positional information of body parts (join receptors, Golgi tendons, muscle spindles)
a. Proprioceptors
Near an epithelial surface (respond to touch, pressure, temperature or pain)
a. Cutaneous receptors
Respond at constant rate as long as stimulus is applied eg pain
a. Tonic receptors
Respond with burst of activity but quickly reduce firing rate to constant stimulation
a. Phasic receptors
Responsible for sensory adaptation (smell and touch)
a. Phasic receptors
In phasic receptors the _______ adapts to a constant stimulus and quickly diminishes in amplitude
a. Generator potential
Cutaneous sensation such as touch, pressure, and heat are mediated by
a. Free and encapsulated nerve endings
Are slow-adapting, expanded free nerve endings that mediate touch
a. Ruffini endings and Merkel’s discs
Encapsulated nerve endings mediate touch, pressure and adapt quickly
a. Meisner’s and Pacinian corpuscles
Minimum distance at which 2 points of touch can be perceived as separate
a. Two-point touch threshold
CNS process that sharpens sensation; sensory neurons at center of stimulation area inhibit more lateral neurons and object are perceived as single touch with well-defined borders
a. Lateral inhibition
Smell olfaction receptors are located in ____ at top of nasal cavity
a. Olfactory epithelium
Receptor cells of olfactory apparatus are bipolar neurons that send axons to
a. Olfactory bulb
Olfactory apparatus Stem cells that produce new receptor cells every 1-2 months
a. Basal cells
Sweet and bitter and Odor molecules bind to receptors and act through
a. G proteins
Provides sense of equilibrium orientation to gravity
a. Vestibular apparatus
Otolith organs consists of
a. Utricle and saccule
Vestibular apparatus consists of
a. Otolith organs and semicircular canals
Utricle and saccule produce info about
a. Linear acceleration
Semicircular canals oriented in 3 planes give sense of
a. Angular (rotational) acceleration
Modified epithelial cells and are receptors for hearing and equilibrium
a. Hair cells
Hair cells contain 20-50 hair like extensions called
a. Stereocilia
1 Longer hair cell extension
a. Kinocilium
Utricle and saccule each have a ___ a patch of specialized epithelium containing hair and support cells
a. Macula
Calcium carbonate crystals that resist change in movements
a. Otoliths
At base of semicircular canals where sensory hair cells are located
a. Crista ampullaris
Hair cell process are embedded in gelatinous membrane ____ with higher density than endolymph
a. Cupula of crista ampullaris
Involuntary oscillations of eyes
a. Vestibular nystagmus
Loss of equilibrium
a. Vertigo
Malleus carries vibration to incus, which goes to stapes and to
a. Oval window
Muscle attached to stapes and provides portion from loud noises
a. Stapedius muscle
Where sound is transduced
a. Organ of corti
Pressure waves moving thru cochlear duct create shearing forces between basilar and _____, moving and bending stereocilia
a. Tectorial membrane
Occurs when transmission of sound waves to oval window is impaired; helped by hearing aids
a. Conduction deafness
Impaired transmission of nerve impulses; helped by cochlear implants
a. Sensorineural deafness
A multilayered epithelium consisting of neurons, pigmented epithelium and photoreceptors (rods and cones)
a. Retina
- Axons of retinal neurons gather at ______ (bind spot) and exit eye in optic disc
a. Optic disc
Part of the external world projected into retina
a. Visual field
Sharpness’ of vision
a. Visual acuity
Ability to distinguish (resolve) 2 closely spaced dots
a. Resolving power
(nearsightedness) image is focused in front of retina because eyeball is too long; object will have to be closer to be seen
a. Myopia
(farsightedness) image is focused behind retina because eyeball too short; object will have to be further away to be seen
a. Hyperopia
Cornea or lens is not symmetrical; light is bent unevenly, causing uneven focus
a. Astigmatism
In dark, photoreceptors release ____ that hyperpolarizes bipolar
a. Inhibitory NT
Light inhibits photoreceptors from releasing _____, thus stimulating bipolars, which excite ganglionic cells, which transit AP to brain
a. Inhibitory NT
T or F cGMP keeps Na+ channels open; light converts cGMP to GMP and Na+ channels close
a. True
Nuclear hormone receptors serve as
a. Transcription factors
Contractile units of skeletal muscle consisting of components between 2 z disc
Sarcomeres
In ______ muscle,
______ blocks binding sites on actin so cross bridge cannot occur; occurs when ca++ levels are low
Relax; tropomyosin
When calcium levels rise, calcium bonds to _____ causing conformational change which moves tropomyosin and exposes binding sites allowing crossbridges and contraction to occur: crossbridges cycles stop when calcium levels decrease
Troponin
Sensitive to horizontal acceleration
Utricle
Sensitive to vertical acceleration
Saccule
Neural stem cells
Ependymal cells
All cells have a negative internal charge and unequal distribution of ions
Resting membrane potential
Result from large anions trapped inside cells
Mp becomes more negative than rmp: inhibitory inhibits nerve impulses
Hyper polarization
Mp returns to RMP
Repolarization.
VG channels are opened by
Depolarization
Mao inhibitors
Antidepressants
Collection of cell bodies outside of cna; located in head neck, abdomen, and parallel to the spinal cord
Autonomic ganglion
Originate in midbrain hindbrain upper thoracic to 4th sacral level of spinal cord
Preganglionic fibers
Some preganglionic neurons that exit the spinal cord below the diaphragm do not synapse in the sympathetic chain of ganglia. Beyond the sympathetic chain these preganglionic fibers form
Sphancnic nerves and synapse in collateral ganglion (preventral ganglia)
