Exam 1 Flashcards
Fitzpatrick Scale
Sunburns based on skin color (type I: white burns easily, type VI: darkest, doesn’t burn)
Malar rash
Lupus, nose and cheeks
Color variation
same disease, different baseline skin phenotypes (ex. tinea vesicolor)
Flat description
Macule (smaller 0.5-1cm)
Patch (larger, >1cm)
Smooth and raised description
cyst, nodule (>5mm), papule (<1cm), plaque (>1cm)
Fluid-filled description
wheal, vesicle, bullae, pustule
Secondary changes in skin
Crust, Scaly (powdery, greasy, gritty)
Red blanchable
erythema, erthyroderma, telangiectasia
Purpuric description
ecchymosis, petechiae, palpable purpura
Sunken description
atrophy, erosion, ulcer
Necrotic
eschar, gangrene (includes purtification)
Main pathology of epidermis
Dermatitis (poor differentiation)
Papulosquamous (well-demarcated)
Intraepidermal bullous (erosions)
Main pathology of dermal-epidermal junction
Subepidermal bullous
autoimmune disease (lupus)
Pigmentary disorders
Main pathology of the dermis
Cellular infiltrates (lymphocytes, histocytes, granulomas)
blood vessels
hair follicles
others: mast cells, eosinophils, neutrophils
Main pathology of fat
Deeper, panniculitis (poorly demarcated pink nodules)
Ecchmosis
Bruising without indicated pattern (hit it on something, etc)
Acral distrubution
Distal body parts, hands and feet
Dermatomal distribution
Supplied by a single spinal nerve
Intertriginious/flexural
where the skin folds/crevaces
Lymphangitic
appears where lymph is in the body
photo distribution
where the sun hits
Scattered vs. widespread
small areas everywhere vs. covering a large area
Annular:
Full circle, circle is a raised ring with normal skin inside
Arcuate
half circle, blanching, barely indurated, (seen in lupus)
Linear
Straight, thickness/induration, blanching (think scabies or other parasites)
Whorled
Follows Blascho’s lines in a twisted pattern
Reticular/morbilliform
“lace-y” no blanching, non-indurated, (seen in measles)
Serpiginous
Whole pattern is snakey, includes arcuates
Targetoid
circular, lymes disease and erythema multiformae
Planar vs cross sectional imaging
3 dimensions translated into 2 (chest x-ray), vs composite analysis of 2-D slices (CT)
Standard radiography
as though the patient is facing you
Standard in body CT
Axial view
Standard in head CT/MRI
Coronal view
Central NS cells
astrocytes, oligodendrocytes, microglia, ependymal cells
Peripheral NS cells
Schwann cells, satellite cells
neuronal staining
Golgi method
Nissl staining
Fiber stains
Myelin stain
Pseudounipolar neuron
1 process, 1 axon that divides close to the cell body (PNS) into 2 long axons (1 to PNS and 1 to CNS)
Bipolar neuron
2 processes, 1 axon and 1 dendrite, 1 cell body (PNS) (RARE: only in retina of eye, cranial nerve VIII of ear)
Multipolar neuron
multiple processes, 1 axon and >2 dendrites. Dendrite –> cell body –> axon
Nissl Bodies
Groupings of organelles. Not present in axon hillock
Fast axon transport system
ATP used
Anterograde: cell body to synapse (Kinesin), 400mm/day
Retrograde: synapse to cell body (dynein), 20mm/day – toxins and viruses travel this way
Slow axon transport system
Anterograde only, 0.5-3mm/day, mechanism unclear
Gray matter
BRAIN: outer layer, deep regions (nuclei)
SPINAL CORD: inner layer
White matter
BRAIN: inner layer
SPINAL CORD: outer layer
Cerebrum gray matter layers
1: plexiform molecular layer
2-3: small pyramidal layer
4: granular layer
5: large pyramidal layer
6: polymorphic layer
Cerebellum cortex layers
Molecular layer: outer layer (light eosin stain)
Purkinje layer: junction of molecular and granular layers
Granular layer: beneath molecular layer (dark hemotoxylin stain)
Endoneurium – PNS fascicle
Loose connective tissue surrounding each axon fiber (fibroblasts)
Perineurium – PNS fascicle
specialized connective tissue surrounding each nerve fascicle (many axons surrounded by endoneurium in here)
Epineurium – PNS fascicle
dense irregular connective tissue that surrounds a peripheral nerve and fills the spaces between nerve fascicles (surrounds many perineurium)
Microglial cells
Enter CNS parenchyma from vascular system, fxn as phagocytes (have same progenitor as macrophages; granulocyte/monocyte in bone marrow)
Ependymal cells
Line central canal of spinal cord and ventricles of brain. simple cuboidal –> columnar epithelial that is ciliated.
Functions: cilia to help move CSF, transport, secretion
Satellite cells
surround neuron cell body for homeostasis
Types of unmyelinated nerves in the PNS
1.) Mesaxon: parallel membranes of a schwann cell (line from unmyelinated axon through schwann cell to the outside)
2.) Bundle of Remak: unmyelinated fibers held closely together
3.) C fibers: unmyelinated fiber, low conductance velocity
Anterograde nerve injury
degeneration proceeds down toward synapse
Retrograde nerve injury
degeneration proceeds up to cell body
Anterograde (Wallerian) degeneration
CNS: oligoden apoptosis, BBB removal barrier, astrocyte scar
PNS: dedifferentiation of schwann cells, phagocytosis by schwann cells and macrophages
Retrograde degeneration
Signaling to cell body causes upregulation of c-Jun transcription factor –> reorganization of cytoplasm and organelles, Chromatolysis (moving of Nissl bodies and nucleus)
Sensory ganglia
Spinal nerves (dorsal root/posterior root)
Cranial nerve ganglia (CN 5, 7, 8, 9, 10)
Autonomic ganglia
sympathetic
parasympathetic
Peripheral sensory system
– Pseudounipolar cells
– Ganglia
– Peripheral and central processes
- AFFERENT, from PNS–>CNS
Peripheral motor system
– Multipolar cells
– CNS (somatic), CNS and ganglia (visceral)
– Dendrites and axons
– EFFERENT, from CNS–>PNS
Osmium
stains white matter black
Where is the lateral horn present?
T1-L2
Dorsal horn
in all levels of the spinal cord, contains SENSORY interneurons (afferent, PNS–>CNS), cell bodies in dorsal root ganglia
Ventral horn
motor neurons (efferent, CNS–>PNS), innervates voluntary skeletal muscles
Dorsal Rami
Epaxial muscles: “true back” muscles, posture head movements,
Ex. splenius capitis, splenius cervicis, erector spinae, transversospinalis
Ventral Rami
Hypaxial muscles: “extrinsic” muscles, limb movements
Ex. Trapezius, Latissimus dorsi, levator scapulae, rhomboid
(exception: sensory info of trapezius is from ventral rami, motor innervation is from CN 11)
Dermatome
The area under the skin supplied at a single spinal cord level, or on one side, by a single spinal nerve. Horizontal on trunk, longitudinal on extremities
Myotome
The skeletal muscles supplied by a single spinal cord level, or on one side, by a single spinal nerve
Plexus
Branching network of intersecting nerves of blood vessels, all white matter no cell bodies
Autonomic NS innervations
– Cardiac and smooth muscle and glands
– Adrenal medulla functions as a postganglionic sympathetic “neuron”
Parasympathetic preganglionic cell bodies located:
“Cranial outflow”
Cranial nerves 3, 7, 9, 10 (in the cervical area)
S2-S4 (sacral)
Sympathetic preganglionic cell bodies located:
“thoracolumbar outflow”
T1-L2
Lateral horn (IML cell column)
Parasympathetic postganglionic cell bodies located:
CN: ganglia along CN 3, 7, 9 OR embedded in target organs
SACRAL: embedded in target organs
sympathetic postganglionic cell bodies located:
45-49 paravertebral ganglia: found in the sympathetic trunk chain (runs head to coccyx)
5-7 prevertebral ganglia: all in abdomen, paired or not, variable)
Cervical ganglia
1.) superior cervical
2.) Middle cervical
3.) Stellate/inferior cervical
^ inferior and 1sy thoracic paravertebral and merged
Sympathetic pre and post ganglion lengths:
short pre in the CNS, long post in the PNS
Parasympathetic pre and post ganglion lengths:
long pre in the CNS, short post in the PNS
White rami vs grey rami locations
grey is lateral (closer to spinal cord) than white
^ Exception is at T1
Preganglionic sympathetic neuron pathway
lateral horn (T1-L2)–> ventral root–> ventral rami–> white rami
paravertebral vs prevertebral pathways
para: Synapse with same level, superior (cranial), inferior (caudal) ganglia
pre: Synapse with postganglionic neurons in prevertebral ganglia or the adrenal gland
Splanchnic nerves
autonomic nerves that supply the internal organs
Cervical and upper thoracic trunk levels
Symp nerve: cardiopulmonary nerves (heart/lung)
Fiber type: postganglionic from paravertebral ganglia
Lower thoracic trunk level
Symp nerve: thoracic splanchnic (abdominal organs)
Fiber type: preganglionic to prevertebral ganglia
L1-2 trunk level
Symp nerve: Lumbar splanchnic (abdominal organs)
Fiber type: preganglionic to prevertebral ganglia
Sacral
Symp nerve: Sacral splanchnic (pelvic organs)
Fiber type: preganglionic to prevertebral
Mechanical, chemical, thermal, and some nociceptive (pain) information travels via
the vagus nerve to the brainstem
–80% of vagus nerve fibers are sensory nerve processes
–20% are preganglionic parasympathetic
Nociceptive signals from the viscera may travel with:
sympathetic axons to DRG and the spinal cord to join somatosensory pain pathwayd
symp gang–> DRG–> spinal cord–> brain
Categories of autonomic drugs
1.) parasympathomimetics
2.) parasympathetic antagonists
3.) sympathomimetics
4.) sympathetic antagonists
Cholinergic systems
1.) Nicotinic receptors–> N1/Nm –> neuromuscular junction
1.) Nicotinic receptors–> N2/Nn –> Autonomic ganglia, CNS
2.) Muscarinic receptors –> M1, M2, M3, M4
Agonists of autonomic system
Muscarine (M1-4), Nicotine (N1-2)
Antagonists of autonomic system
Atropine (M1-4), Hexamethonium (N2)
Muscarinic receptors
GCPRs 4 steps:
1.) 1 ACh binds receptor, changing configuration
2.) G protein is activated
3.) effector protein is activated
4.) ion channel opens or closes (or some other intracellular protein is affected)
Effector receptor subtypes:
M1: CNS, GI tract, lymphcytes
M2: CNS, heart, smooth muscles (stomach, bladder, airways)
M3: CNS, GI tract, smooth muscle
M4: CNS
M5: CNS, esophageal smooth muscle, lymphocytes, salivary gland
alpha receptors
norepinephrine and epinephrine
beta receptors
epinephrine»_space; norepinephrine
Gs is beta adrenergic and
increased cAMP/ Ca2+ release
Gi is alpha2 adrenergic (mAChR) and
decreases cAMP/ Ca2+ release
alpha2 is unique in that is can also act PREsynaptically to inhibit norepinephrine
Gq is alpha1 adrenergic (mAChR) and
activates PLC-IP3 to increase Ca2+ release
4 actions of norepinephrine
1.) Alpha2 presynaptically to decrease NT release
2.) Alpha1 postsynaptically to increase Ca2+
3.) Beta1 postsynaptically to increase cAMP
4.) Alpha2 postsynaptically to decrease cAMP
Skin blood flow
pressure= flow x resistance
Antagonists of Alpha1 and 2
Prazosin, Yohimbine
Antagonists of Beta 1-3
Beta blockers, “olols”
Apical skin
– sympathetic activity for vasoconstriction
– AVA (glomus body)
– capillary sphincter
– no capacity for dilation, must use sphincter to prohibit flow through capillaries and make it go through AVA
Nonapical skin
– Sympathetic activity for vasoconstriction
– Sympathetic activity for vasodilation (cholinergic, ACh/bradykinin)
– NO AVA !
Vasoconstrictions is
Sympathetic adrenergic
Mech: Release NE from postgang symp nerves –> binding alpha1 and 2 –> smooth muscle contraction –> vasoconstriction –> reduce heat loss
Vasodilation is
Sympathetic cholingergic
Mech 1: release of ACh from postgang symp nerves –> bind M3 in endothelial –> release NO –> smooth muscle relaxation –> vasodilation –> increase heat loss
Mech 2: release of ACh from postgang symp nerves –> bind M3 in sweat glands –> release bradykinin –> vasodilation –> increase heat loss
Raynaud’s Phenomenon
Spasms in skin blood vessels in response to cold, stress, or emotional upset. Mostly in hands, especially apical skin
Pattern:
1.) pallor (less pink) as blood flow stops
2.) Cyanosis (blue) as O2 levels drop in the tissue
3.) Rubor (red) as vessels reopen
Sweat step 1.) Secretion
1.) Na/K ATPase sets up sodium gradient
2.) Na/K/2Cl transporter moves Na out of cell
3.) CLCA move Cl out of cell into lumen of gland
4.) H2O follows via aquaporins
Sweat step 2.) reabsorption of NaCl
1.) Na/K/ ATPase sets up sodium gradient
2.) apical Na absorption via ENaC
3.) Cl absorption via CFTR
4.) H2O CANNOT follow due to tight junctions
^^ this is why sweat is hypotonic
Eccrine sweat (thermal)
Since birth, located everywhere, opening via pores, secretes water and viscous fluid, CHOLINERGIC (M)
Apocrine (emotional)
Since puberty, restricted to the axilla, areolae, and external genitalia, opening near hair follicles, secretes viscous fluid that becomes odored when acted on by bacteria, ADRENERGIC (beta)
Hyperhydrosis
excessive secretion of thermoregulatory sweat. Treatment includes anticholinergic such as atropine (M antagonist), furosemide (blocks NKCC1), or botulinum toxin injection (BOTOX, blocks ACh release)
Bromhidrosis
excessive malodorous (apocrine) sweating. Treatment includes acting on the bacteria, so antibacterial and antiperspirants
Piloerection
Goosbumps, mediated by alpha1 adrenergic receptors
Stimuli includes: cold temperatures, intense emotions, medications
