Exam 2 Flashcards
Autonomic nervous system
composed of the Sympathetic and the Parasympathetic systems that exerts control over the functions of many visceral organs and tissues in the body.
Sympathetic leads to
increased heart rate, constriction of the arterioles of the skin and intestine, raises the blood pressure, dilation of the pupils, sphincters close, hair stands and sweating occurs.
Parasympathetic leads to
Decrease in heart rate, pupil constriction, increased peristalsis, increased glandular activity, sphincters open, bladder wall is contracted.
Where is parasympathetic ganglia located?
in or near the effector organs
Where is sympathetic ganglia located?
paravertebral chain
sympathetic nervous system
prepares and mobilizes the body in the emergency cases (exercise, fear..)
-acetylcholine
-located w/in cns
parasympathetic nervous system
conserves and stores energy (during sleep)
-cns in brain and spinal cord
-acetylcholine, norepinephrine, epinephrine
Sympathetic (thoraco-lumbar) Origin
cell bodies lie the lateral horn of the T1- L2/3 spinal cord
parasympatheic (cranio-sacral) origin
CN III, CN VII, CNIX and CN X and S1, S2, S3 (pelvic splanchnic nerve)
Preganglionic and postganglionic neurons of sympathetic system release what?
Preganglionic release neurotransmitter ACH and post releases norepinephrine
Preganglionic and postganglionic neurons of Parasymatheic system release what?
Both releases ACH
Peptidergic neurons in the parasympathetic nervous system release what?
peptides such as vasoactive inhibitory peptide and substance P.
Adrenergic neurons release what?
norepinephrine as the neurotransmitter
The postganglionic fiber of parasympathetic is _______ then postganglionic fiber of sympatheitic?
Shorter
Alpha 1 receptors location
vascular smooth muscle, splanchnic regions, the GI tract, bladder sphincters, and the radial muscle of the iris.
Alpha 1 receptors Mechanism of action
G protein alpha stimulator, Phospholipase C, formation of inositol 1,4,5-triphospate (IP3) and increase in intracellular (Ca2+).
Alpha 1 receptors function
Vasoconstriction, contraction
Alpha 2 receptors location
located in presynaptic nerve terminals, platelets. Fat cells, and the walls of the GI tract.
Alpha 2 receptors Mechanism of action
G protein alpha inhibitor, inhibition of adenylate cyclase and decrease in cyclic adenosine monophosphate (CAMP).
Alpha 2 receptors function
produce inhibition (relaxation or dilation)
beta 1 receptors location
sinoatrial (SA) node, atrioventricular (AV) node, and ventricular muscle of the heart.
beta 1 receptors Mechanism of action
activation G protein alpha stimulator, activation of adenylate cyclase and increase in cAMP.
beta 1 receptors function
produce excitation (increased heart rate, increased conduction velocity, increased contractility).
beta 2 receptors location
vascular smooth muscle of skeletal muscle, bronchial smooth muscle, and in the walls of the GI tract and bladder
beta 2 receptors Mechanism of action
activation G protein alpha stimulator, activation of adenylate cyclase and increase in cAMP
beta 2 receptors function
produce relaxation (dilation of vascular smooth muscle, dilation of bronchioles, relaxation of the bladder wall.)
Nicotinic receptor’s location
autonomic ganglia of the sympathetic and parasympathetic nervous systems, at the neuromuscular junction, and in the adrenal medulla
Nicotinic receptor’s Mechanism of action
ACh binds to alpha subunits of the nicotinic Ach receptor, The nicotinic Ach receptors are also ion channels for Na+ and K+
Nicotinic receptor’s function
produce excitation
Muscarinic receptors location
located in the heart, smooth muscle, and glands
Muscarinic receptors Mechanism of action (heart SA node)
inhibition of adenylate cyclase, which leads to opening of K+ channels, slowing of the rate of spontaneous Phase 4 depolarization, and decreased heart rate
Muscarinic receptors Mechanism of action (smooth muscle and glands)
formation of IP3 and increase in intracellular (Ca2+)
Muscarinic receptors function
inhibitory in the heart (decreased heart rate, decreased conduction velocity in AV node).
are excitatory in smooth muscle and glands (increased GI motility, increased secretion).
The medulla is the control center for what?
Vasomotor center, Respiratory center, Swallowing, coughing, and vomiting centers
Pons in the control center for what?
Pneumotaxic center
Midbrain is the control center for what?
Micturition center
Hypothalamus is the control center for what?
Temperature regulation center, Thirst, and food intake regulatory centers
Chronotropic
means it influences heart rate by increasing it
Dromotrophic
decreases heart rate
Effects of ANS eye (pupil)
sympathetic: alpha 2 receptor: dialation;
parasympathetic: constriction
Effects of ANS eye (ciliary muscle)
sympathetic: beta receptors: accommodation;
parasympathetic: contraction
Effects of ANS eye (lacrimal gland)
sympathetic: decreased secretion;
parasympathetic: increased secretion
Effects of ANS heart (coronary arteries)
sympathetic: vasodilation; beta 1 rec: +ve chronotropic (increased heart rate); beta 1 rec: +ve dromotropic (increased contraction of myocardium)
parasympathetic: vasoconstriction; -ve chronotropic; -ve dromotropic
Effects of ANS lung (bronchi muscle)
sympathetic: b2 rec: dilation
parasympathetic: constrictor
Effects of ANS lung (vessels)
sympathetic: constriction
parasympathetic: dilation
Effects of ANS lung (glands)
sympathetic: decreased secretion (good)
parasympathetic: increased secretion (bad)
Effects of ANS GI tract (peristalsis (tonus))
sympathetic: b2 rec: relaxation;
parasympathetic: activation
Effects of ANS GI tract (sphincters)
sympathetic: a1 rec: constriction;
parasympathetic: relaxation
Effects of ANS GI tracts (glands)
sympathetic: decreased secretion;
parasympathetic: increased secretion
Effects of ANS (liver)
sympathetic: b rec: gluconeogenesis;
parasympathetic: glycogenesis
Effects of ANS Gall bladder (sphincters)
sympathetic: b2 rec: relaxation;
parasympathetic: constriction
Effects of ANS Pancreas (Insulin)
sympathetic: a rec: inhibits its secretion; b rec: activates its secretion
Effects of ANS Pancreas (Exocrine)
sympathetic: a rec: inhibits secretion;
parasympathetic: activates secretion
Effects of ANS Adrenal Medulla
sympathetic: activates secretion
Effects of ANS Urinary Bladder (Sphincter M.)
sympathetic: a rec: contraction;
parasympathetic: relaxation
Effects of ANS Urinary bladder (Detrusor M.)
sympathetic: b rec: relaxation;
parasympathetic: contraction
Effects of ANS Uterus (pregnant)
sympathetic: A1 rec: contraction
Effects of ANS Uterus (non-pregnant)
sympathetic: b2: relaxation
Effects of ANS Genitals
sympathetic: ejaculation (emission)
parasympathetic: erection (vasodilation) + ejaculation
Sensory transducer Mechanoreceptors
respond to touch/mechanical stimulus. examples are, Stretch receptors in muscle, joint receptors, Hair cells in auditory and vestibular systems, and Baroreceptors in the carotid sinus
Sensory transducer Photoreceptors example
Rods and cones of the retina
Sensory transducer Chemoreceptors examples
Olfactory receptors, Taste receptors, Osmoreceptors, Carotid body O2 receptors
Sensory transducer Nociceptors are used to sense what?
Extremes of temperature and pain
fiber type A (A-alpha)
large, alpha-motoneurons; conduction velocity: fastest
fiber type A (A-beta)
touch, pressure; CV: medium
fiber type A (A-gamma)
gamma-motoneurons to muscle spindles (intrafusal fibers); CV: medium
fiber type A (A-delta)
touch, pressure, temperature, and pain; CV: medium
fiber type B
preganglionic autonomic fibers
CV: medium
fiber type c
slow pain, postganglionic autonomic fibers
CV: slowest
Sensory Pathway Step 1
sensory receptors (epithelial cells or afferent neurons) are activated by environmental stimuli that converts the stimulus into electrical energy
Sensory Pathway Step 2
First-order neurons (primary afferent neurons) in the dorsal portion of spinal cord receive the signal and send the information to the CNS.
Sensory Pathway Step 3
Second-order neurons in the spinal cord or brain stem receives the information and sends it to the contralateral thalamus
Sensory Pathway Step 4
Third-order neurons in the thalamus sends the encoded sensory information to the cerebral cortex
Sensory Pathway Step 5
Fourth-order neurons in the cerebral cortex received the information which results in a conscious perception of the stimulus.
Dorsal column system is a type of ________ that detects________?
pathway in the somatosensory system; sensations of fine touch, pressure, two-point discrimination, and vibration.
Anterolateral system is a type of ________ that detects________?
pathway in the somatosensory system; sensations of temperature, pain, and light touch.
Thalamus information is arranged how?
Has Information from different parts of the body arranged somatotopically
Damage to right side of thalamus could cause what?
loss of sensation on the controlateral side (left side) of the body.
Damage to left side of thalamus could cause what?
loss of sensation on the controlateral side(right side) of the body.
What is referred pain?
Sites on the skin that are innervated by nerves that arise from the same segment of the spinal cord.
What is an example of referred pain?
when ischemic heart pain is referred to the chest and shoulder.
Taste is a sense called ______ that falls under the category of ______?
Gustation; Chemoreception.
What are the 3 Innervations of Taste?
CN VII ( Chorda tympani branch of facial nerve), CN IX ( Glossopharyngeal nerve), and Vagus nerve branch
What are the 4 types of taste and their receptors?
Salt with NaCl receptors, Sour with three different receptor proteins for acidic compounds, Bitter with G-protein coupled receptors (GPCR’s), Sweet with GPCR’s receptors.
What is Ageusia?
loss of sense of taste when the facial nerve is
Damaged.
What is Hypogeusia and Hypergeusia?
Hypogeusia is decreased taste sensitivity and Hypergeusia is increased taste sensitivity
What causes a sore tongue?
some form of trauma, such as biting your tongue, or eating piping-hot or highly acidic food or drink.
What disorders can cause sore tongue?
diabetes, anemia, some types of vitamin deficiency and certain skin diseases
What is Glossodynia?
a burning sensation on the tongue
What is Benign migratory glossitis (geographic tongue)?
it is an unknown condition where there is irregular and inflamed patches on the tongue surface that often have white borders.
Symptoms of Benign migratory glossitis
swollen, red and sore tongue
Where are olfactory receptors located and what do they do?
they are located in the olfactory epithelium and they are true neurons that conduct action potentials into the CNS
What does CN I (olfactory nerve) do?
carries information from the olfactory receptor cells through the cribriform plate to the olfactory bulb.
The Axons of the olfactory nerves are ______ _____ fibers and are the ________ and ________ nerves in the nervous system
unmyelinated C; smallest and slowest
What can happen with cribriform plate fractures?
Fractures of the cribriform plate sever input to the olfactory bulb and reduce (hyposmia) or eliminate (anosmia) the sense of smell.
What nerve is unaffected by cribriform plate fractures and can detect pain?
CN V ( trigeminal nerve)
What is Anosmia?
Anosmia is the lack of olfaction or a loss of the sense of smell.
What is Phantosmia?
Phantosmia is the phenomenon of smelling odors that aren’t really present.
What is Dysosmia?
When things smell differently than they should.
What are the 3 layers that make up the exterior wall of the eyeball in order from outer to innermost layers?
sclera, choroid, and retina.
What is the outermost layer of the eye and what does it do?
The outer layer of the eye is the sclera, which is a tough white fibrous layer that maintains, protects, and supports the shape of the eye.
What is the cornea and where is it located?
The front of the sclera is transparent and is called the cornea. The cornea refracts light rays and acts like the outer window of the eye.
What is the choroid and its function?
it is the vascular layer of the eye lying between the retina and the sclera that provides oxygen and nourishment to the layers of the retina. It also contains a non-reflective pigment that acts as a light shield and prevents light from scattering.
What is the retina and its location?
its the third or the inner layer of the eye lays over the back two thirds of the choroid coat, which is located in the posterior compartment filled with vitreous humor.
What are photoreceptors?
Within the retina there are cells called rod cells and cone cells also known as photoreceptors.
What part of the eye lacks photoreceptors?
The optic disc also known as “the blind spot”
Whats important about rods in the eyes?
The rod cells are very sensitive to light and do not see color
Whats important about cones in the eyes?
The cone cells are sensitive to different wavelengths of light, and that is how we are able to tell different colors.
What causes people to have deficiencies in their color vison or color blindness?
a lack of cones sensitive to red, blue, or green light
What is the fovea centralis?
Where the cone cells are densely packed. The fovea is a pit that has the highest visual acuity and is responsible for our sharp central vision
There are rods in the fovea centralis true or false?
False there are no rods in there
What are the layers of the retina in order?
Pigment epithelial cell, Receptor cells (rods and cones), Bipolar cells, Horizontal cells, Amacrine cells, and Ganglion cells.
What layer of the retina are output cells and forms the optic nerve with its axons?
Ganglion cells
Steps in photoreception in the Rods Step 1
Light hits the rhodopsin (composed of scotosin and 11-cis retinal) in the rod cell
Steps in photoreception in the Rods Step 2
Because of light hitting rhodopsin the 11-cin retinal turns into all-trans retinal though a precess called photoisomerization
Steps in photoreception in the Rods Step 3
all-trans retinal activates metarhodopsin II
Steps in photoreception in the Rods Step 4
Metarhodopsin II then activates G protein (transducin), which in turn activates a phosphodiesterase.
Steps in photoreception in the Rods Step 5
Phosphodiesterase decrease cGMP in the cell
Steps in photoreception in the Rods Step 6
the decreased cGMP cause the closure of Na+ channels in the rod cell which means there is no depolarization and this causes Hyperpolarization
Steps in photoreception in the Rods Step 7
There is a decreased release of exitatory or inhibitory neurotransmitters by the rod cell because of the hyperpolariation
What happens when the decreased release of neurotransmitter in the rod cells are exitatory?
then the response of the bipolar or horizontal cell
to light is hyperpolarization.
What happens when the decreased release of neurotransmitter in the rod cells are inhibitory?
then the response of the bipolar or horizontal cell
to light is depolarization.
What vitamin is necessary for the regeneration of 11-cis retinal and if dificent causes night blindness?
Vitamin A
What are the primary visual areas in the occipital lobe?
17, 18 and19
Optic pathway
Axons from retinal ganglion cells that form the optic nerves and optic tracts receives the light signal
The optic nerve and optic tract synapse in the lateral geniculate body of the thalamus and ascends to the visual cortex
Pathologic of optic pathways Right side of L & R eye Step 1
Signals that come from right temporal field
Pathologic of optic pathways Right side of L & R eye Step 2
goes to the left nasal portion of retina and it passes through the optic chiasm
Pathologic of optic pathways Right side of L & R eye Step 3
left optic tract
Pathologic of optic pathways Right side of L & R eye Step 4
left thalamus which has the lateral geniculate nucleus
Pathologic of optic pathways Right side of L & R eye Step 5
then it forms a synapse with next group of neurons that travels to the occipital lobe area 17,18,19.
Pathologic of optic pathways Left side of L & R eye Step 1
Signals that come from left temporal field
Pathologic of optic pathways Left side of L & R eye Step 2
goes to the right nasal portion of retina and it passes through the optic chiasm
Pathologic of optic pathways Left side of L & R eye Step 3
right optic tract
Pathologic of optic pathways Left side of L & R eye Step 4
right thalamus which has the lateral geniculate nucleus
Pathologic of optic pathways Left side of L & R eye Step 5
then it forms a synapse with next group of neurons that travels to the occipital lobe area 17,18,19
What happens when the optic nerve is cut?
Cutting the optic nerve causes blindness in the ipsilateral (same side) eye. Thus, cutting the left optic nerve causes blindness in the left eye.
What happens when the lateral part of the left optic nerve is cut?
It affects the nasal field on left eye.
what happens when the optic chiasm is cut?
It affects left temperal field and the right temporal field.
what happens if the left optic tract is cut?
It effects the left nasal field and right temporal field.
what happens if the lower part of left optic tract is cut?
It effects the left nasal field and right temporal field.
What is color blindness?
inability to perceive differences between some or all colors that other people can distinguish.
What are the causes of color blindness?
It is most often of genetic nature, but may also occur because of eye, nerve, or brain damage, or due to exposure to certain chemicals.
What are the causes of night blindness?
Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A). The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light.
Glaucoma is due to the closure of what?
The canal of schlemm
What is Glaucoma?
Intracranial pressure
What does Emmetropia mean?
When light focuses on the retina of the eye. This is normal
What is hyperopia?
When light focuses behind the retina. This is corrected with a convex lens for farsighted people.
What is myopia?
When light focuses in front of the retina. This is corrected with a biconcave lens for nearsighted people.
What is astigmatism?
Its when the curvature of the lens is not uniform and is corrected with a cylindric lens.
What are the 3 divisions of the ear?
The outer ear, middle ear, and the inner ear.
Parts of the outer ear (most external portion)
Auricle, Auditory Canal, and Surface of Ear Drum (typanic membrane).
Parts of middle ear
its air filled and contains the rest of the tympanic membrane, the 3 ear bones ossicles (malleus, incus,stapes) and the opening of the Eustachian tube.
The ____ acts like a bridge between the malleus and stapes
the incus
What is the smallest bone in the human body and what does it to?
The stapes is the smallest named bone in the human body. The stapes transfers the vibrations of the incus to the oval window.
Parts of the inner ear (internal ear)
its fluid-filled and contains the Cochlea, Vestibule, Semi-Circular Canals (vestibular system), the ducts called membranous labyrinth (perilymph and endolymph)
Perilymph
The fluid outside the ducts
Endolymph
The fluid inside the ducts
Where is the location of the organ of Corti?
The organ of Corti is located on the basilar membrane that borders the scala media of the cochlea
What does the organ of Corti contain?
It contains the receptor cells for auditory stimuli.
What tubular canal in the cochlea contains endolymph?
scala media
What tubular canals in the cochlea contains perilymph?
scala vestibuli and scala tympani.
Steps on auditory transduction and pathway Step 1
The sound waves pass through the auditory tube and then it pushes the tympanic membrane
Steps on auditory transduction and pathway Step 2
The tympanic membrane vibrates the 3 ear bones (malleus, incus,stapes)
Steps on auditory transduction and pathway Step 3
The stapes bone that is connected to the oval window moves and causes the oval window to move the perilymph inside the scala vestibule
Steps on auditory transduction and pathway Step 4
Then the vibration continues to the inside of the scala tympani that moves the basilar membrane
Steps on auditory transduction and pathway Step 5
The basilar membrane moves the hair cells in the organ of the Corti
Steps on auditory transduction and pathway Step 6
The hair cell’s cilia bend from the movement and push against the tectorial membrane
Steps on auditory transduction and pathway Step 7
The cilia bending one-way causes hyperpolarization the cilia bending the other way causes depolarization
Steps on auditory transduction and pathway Step 8
The depolarization causes the opening of K+ channels that enters into the hair cells
Steps on auditory transduction and pathway Step 9
K+ causes the release of stimulatory neurotransmitters
Steps on auditory transduction and pathway Step 10
The neurotransmitters stimulate the afferent cochlear nerves which take the info to the dorsal and ventral cochlear nuclei of the medulla
Steps on auditory transduction and pathway Step 11
Medulla sends axons to the lateral lemniscus and the inferior colliculus in the CNS
Steps on auditory transduction and pathway Step 12
the inferior colliculus sends the info to medial geniculate nucleus in the thalamus
Steps on auditory transduction and pathway Step 13
The medial geniculate nucleus sends info to the auditory cortex/area 41 42 and the temporal lobe
Steps on auditory transduction and pathway Step 14
Then we can perceive the sound
Auditory Pathways Step 1
The neurotransmitters stimulate the afferent cochlear nerves which take the info to the dorsal and ventral cochlear nuclei of the medulla
Auditory Pathways Step 2
Medulla sends axons to the lateral lemniscus and the inferior colliculus in the CNS
Auditory Pathways Step 3
the inferior colliculus sends the info to medial geniculate nucleus in the thalamus
Auditory Pathways Step 4
The medial geniculate nucleus sends info to the auditory cortex/area 41 42 and the temporal lobe
Auditory Pathways Step 5
Then we can perceive the sound
What is Otitis media?
inflammation of the middle ear segment. It is usually associated with a buildup of fluid and frequently causes an earache.
What bacteria causes Otitis media?
Streptococcus pneumoniae, Haemophilus influenzae (both are the most common), and the common cold.
Otitis media bacterial infection can lead to?
bacterial meningitis
Steps on how Otis media occurs Step 1
tissues surrounding the Eustachian tube swell and block the tube due to an infection and/or severe congestion.
Steps on how Otis media occurs Step 2
The air present in the middle ear is slowly absorbed into the surrounding tissues.
Steps on how Otis media occurs Step 3
A strong negative pressure creates a vacuum in the middle ear
Steps on how Otis media occurs Step 4
The vacuum reaches a point where fluid from the surrounding tissues accumulates in the middle ear
What is the purpose of the Vestibular system?
To maintain equilibrium
or balance by detecting angular and linear accelerations of the head.
What structure in the vestibular organ detects angular acceleration or rotation?
The semicircular canals ( 1, 7 and 8 on picture)
What does the utricle and the saccule detect?
Linear acceleration
Where are the hair cells located in the vestibular organ?
The
end of each semicircular canal (ampulla).
Vestibular pathways Step 1
After the depolarization of hair cells, the information goes to the vestibule ganglion which synapses with a group of neurons that make up the vestibular nuclei in the brain stem that travel to multiple places in the CNS.
Vestibular pathways Step 2
The first group: of neurons travels to the cerebellum and controls the general movement of the body and balance
Vestibular pathways Step 3a
The second group of neurons travels to the right nucleus in the midbrain.
Then the information travels back to the spinal cord via the rubrospinal tract
Vestibular pathways Step 3b
The rubrospinal tract controls the flexor muscles of the upper and lower limb
Vestibular pathways Step 4
The third group (lateral group and medial group): sends information back to the spinal cord via the vestibulospinal tract
Vestibular pathways Step 4a Lateral
The vestibulospinal tract controls the extensor muscles of the upper and lower limbs
Vestibular pathways Step 4b Medial
The information travels to the nuclei of CN II, IV, and VI that controls the eye movement (that’s why eyes move when the head turns)
Vestibular pathways Step 4c
The next group travels to the reticular nucleus then to the spinal cord via the reticulospinal tract
What is nystagmus?
Abnormal movement of the eye due to damage of some CN’s.
Nystagmus can be?
Congenital, pathologic or physiologic
What does nystagmus cause?
Uncontrolled rapid eye movement in the same direction as head rotation
What is Post-rotatory nystagmus?
Nystagmus that occurs in the opposite direction of the head rotation
What can vertigo be caused by?
It can be caused by hypertension or hypotension, high blood cholesterol or low blood cholesterol, pregnancy, damaged vestibular system, or bacterial infection.
What is vertigo?
a problem in the inner ear balance mechanisms (vestibular system), in the brain, or with the nerve connections between these two organs.
What does vertigo cause?
dizziness
What happens if the person turns the head to the right side? Step 1
Endolymph initially goes to the opposite direction (left)
What happens if the person turns the head to the right side? Step 2
Cupula also goes to the opposite direction (left)
What happens if the person turns the head to the right side? Step 3
Cupula returns to normal position when adaptation is achieved
What happens if the person turns the head to the right side? Step 4
When the head stops rotation, endolymph moves to the same direction of the head turning.
What happens if the person turns the head to the right side? Step 5
Cupula goes to same direction (the direction of head turning) until movement of endolymph stops and cupula returns to normal position.
List the Characteristics of neurons
Conduct electrical impulses along the plasma membrane, Produce nerve impulse, Produce action potential, Longevity: can live and function for a lifetime, Do not divide: fetal neurons lose their ability to undergo mitosis, High metabolic rate: require abundant oxygen and glucose
What are supporting cells for neuron functions?
To provide supportive functions for neurons and to cover nonsynaptic regions of the neurons.
What are the 2 types of supporting cells in the PNS?
Schwann cells & Satellite cell or ganglionic gliocytes
What is the function of satellite cells?
They support neuron cells bodies within the ganglia of the PNS.
What are the four types of supporting cells in the CNS?
Oligodendrocytes, Microglia, astrocytes, Ependymal cells.
True or false Schwann cells form myelin sheaths on axons in the CNS?
False. Oligodendrocytes form them in the CNS and Schwann cell from them in the PNS.
What is the function of Microglia?
Normally they are inactive but when there’s inflammation or degeneration then they activate and migrate through the CNS and phagocytose foreign or degenerated material.
List the functions of astrocytes 1
They form a supportive framework for neurons and in embryos they serve as a scaffolding for migration of immature neurons.
List the functions of astrocytes 2
they cover the synaptic contacts between neurons and thus insulate axon terminals from influencing neighboring unrelated neurons
List the functions of astrocytes 3
They absorb glutamate and GABA thus limiting the influence of these neurotransmitters.
List the functions of astrocytes 4
They absorb excess K+ of extracellular fluid
List the functions of astrocytes 5
Perform phagocytosis of degenerated axon terminals.
List the functions of astrocytes 6
Replacement gliosis: when neurons die due to disease or injury, they proliferate and fill the spaces previously occupied by neurons.
List the functions of astrocytes 7
induce the formation of the blood-brain barrier.
List the functions of astrocytes 8
produce trophic substances for neurons.
What is the function of ependymal cells?
They line the internal environment of ventricles in the brain and the central canal of the spinal cord.
Is Oligodendrocytes surrounded by a basement membrane?
No but Schwann cells in PNS are.
How do Oligodendrocytes respond to injury?
They respond to injury by expanding and vacuolation of their cytoplasm.
What is Gliosis?
hyperplasia and hypertrophy of astrocytes that occur in reaction to CNS injury.
Tumors of Neuroglia account for about ____% of intracranial tumors
50%
What are 2 tumors of astrocytes?
Astrocytomas and glioblastomas
Gliomas
are very invasive tumors and grow large with minimal effect on neighboring neurons
What is Multiple sclerosis (MS)?
When there are damages/demyelination to the myelin sheath of an axon in the CNS.
What disorders does a person with MS have?
Motor and sensory disorder
At what ages does Multiple sclerosis occur?
between ages of 20-40
How can you treat Multiple sclerosis?
Steroids to prevent severe inflammation
What are neurotrophins?
chemicals that promote neuron growth in a developing fetal brain
What are the 4 neurotrophins?
Nerve growth factor (NGF), Brain-derived neurotrophic factor (BDNF), Glial-derived neurotrophic factor (GDNF), and Neurotrophin-3
Why is Neurotrophin-3 important?
it is important in the embryonic development of sensory neurons and sympathetic ganglia.
What is the blood-brain barrior (BBB)?
is the barrier between cerebral capillary blood and the CSF
What can destroy the BBB?
Inflammation, irradiation, and tumors may destroy the blood-brain barrier and permit entry into the brain of substances that are usually excluded
List the functions of the BBB
It maintains a constant environment for neurons in the CNS and protects the brain from endogenous or exogenous toxins.
It prevents the escape of neurotransmitters from their functional sites in the CNS into the general circulation
When CSF is compared to blood it has the same concentrations of what?
Na+, Cl-, HCO3-, and Osmolarity
When CSF is compared to blood it has less concentrations of what?
CSF has less concentrations of K+, Ca2+, Glucose, cholestrol, and Protein.
CSF has more concentrations of _____ and ______ when compared to the blood
Mg2+ and Creatinine
What are the two inhibitory nurotrasmitters?
Glycine and GABA
List the stimulatory neurotransmitters:
ACH, norepinephrine, epinephrine, dopamine, serotonin, enkephalines, substance P and glutamic acid.
Parkinsons can be treated by what?
Neurotransmitters
Can dopamine cross the BBB?
No only L-dopa can
What is Neuropeptide Y and what does it do?
is a 36 amino acid peptide neurotransmitter found in the brain and autonomic nervous system. It augments the vasoconstrictor effects of noradrenergic neurons.
What precesses is Neuropeptide Y involved in?
regulation of energy balance, memory, learning, and appetite.
What is the functions of neurotransmitter nitric oxide?
Vasorelaxation of blood vessels the effects penile erections, Neurotransmission, modulation of the hair cycle
