Intro to Anatomy Flashcards
What is a neuron’s resting membrane potential?
-65mv
what is the threshold potential of a neuron?
-55mv
- Na+ channels open at start of axon hillock
- chain reaction down the axon
- inside charge becomes around +40mv
hyperpolarized: relative refractory period (charge?)
- Na+ channels closed (not inactive), K+ channels still open
- membrane is now -75 mv
- once K+ channels close, membrane potential returns to -65
Saltatory conductin
- “jumping” of action potential to speed it up
- Na+ ions push each other through myelinated sections, impulse is only truly propagated through nodes of ranvier
Cranial Nerves Acronym
Oh Oh Oh To Try At Futbol
Victor Goes to Vagus And Hides
Only One Of The Two Athletes Felt Very Good, Victorious, And Healthy
CN Functions Acronym
Some Say Marry Money But My Brother Says Big Brains Matter Most
CN 1
Olfactory (S)
-smell
-test by having patient smell something strong with eyes closed (cinnamon)
CN II
Optic (S)
-vision
CN III
Oculomotor (M)
-movement of eye
-pupil constriction
-lens accommodation (follow finger)
-raises upper eyelid
-elevates and abduct (out), depress and adduct, and just adduct the eye
-drooping eyes? CN III might be the issue
CN IV
Trochlear (M)
-movement of eye
-abduct, depresses and internally rotates eye
-test CN III, IV, and VI by following a finger
CN V
Trigeminal (B)
-3 branches:
-V1: ophthalmic: sensory to upper eyelid, nose, forehead and scalp
-V2: maxillary: sensory to maxilla, nasal cavity, palate and skin of cheeks
-V3: Mandibular:
-Motor: chewing muscles
-sensory: lower lip, lower teeth, chin and temporal region of scalp, anterior 2/3 of tongue
-can you feel me touch your face and bite down?
CN VI
Abducens (M)
-motor of the eye
-abduction (!) of the eye
-if everything else is okay except abduction in test, pinpoint VI
CN VII
Facial (B)
-5 extracranial branches
-temporal
-zygomatic
-buccal
-mandibular
-cervical
-innervate muscles in charge of facial expression (smiling/frowning)
-bels palsy or stroke
(F-five, F-Facial)
CN VIII
Vestibulocochlear nerve (S)
-2 branches:
-vestibular: equilibrium receptors
-cochlear: hearing receptors
CN IX
Glossopharyngeal (B)
-motor: elevates pharynx during swallowing (parasympathetic motor fibers to salivary glands)
-Sensory: taste from posterior 1/3 of tongue
-touch and pain from pharynx (sore throat)
(more next chapter: also plays a role in chemoreceptors in the carotid bodies for respiration and baroreceptors of carotid sinus for BP monitoring)
CN X
Vagus (B)
-Only CN that extends past the neck
-somatic motor innervation to muscles of pharynx and larynx involved in swallowing
-parasympathetic fibers to the heart, lungs and abdominal organs to help regulate heart rate, breathing, and digestion
-swallowing, uvula movement (if uvula is stuck in the right position, think issue is with the left side)
CN XI
Accessory Nerve (M)
-Innervates trapezius and SCM muscles (sternocleidomastoid [large muscle in front of neck])
-shrug test
CN XII
Hypoglossal nerve (M)
-motor: muscles of the tongue
-sensory: proprioceptive info from the tongue (movement, action, location)
-actually superior to CV XI
Quadrants: RUQ
liver, gallbladder, head of pancreas, part of large intestine (transverse), duodenum, adrenal gland (ad to renal aka on top of kidney), kidney, ureter
LUQ
Stomach, large/transverse, spleen, kidney/adrenal/ureter, pancreas
-epigastric: pancreas, stomach
RLQ & LLQ
Reproductive organs (uterus, ovaries), bladder, distal ureters, small intestine
-RLQ: appendix
Anterior and posterior are also known as:
Ventral and dorsal, respectively (dorsal fin)
ipsilateral/contralateral
same side/different sides
Superior/inferior are also known as:
cranial/caudal
abduction vs adduction
abduction: away from the body
adduction: towards the body
palpation vs percussion
palpation: pressing on body surface
percussion: tapping
Why are all cell bodies are found in the CNS (or near it)?
Better protected compared to arms and legs
Why are there no nodes of ranvier in the CNS? (??????????????) was ruzga wrong
No Schwann cells (oligodendrocytes)
-White matter is found in the brain/spinal cord and appears white due to myelin (which is the result of oligodendrocytes)
Polarization is what kind of potential?
Resting
What stops a neurotransmitter from repeatedly firing?
Enzyme might break it down (cholinesterase) or reuptake and reuse
What would you notice about a patient who has damaged myelin?
Slower moving
Are most synapses excitatory or inhibitory?
Excitatory (causes action potential)
What happens at an inhibitory synapse?
neurotransmitter causes the postsynaptic neuron to hyperpolarize
-neuron membrane becomes more positive outside as K+ ions leave or Cl- enter the cell (no impulse)
(essentially keep the neuron below threshold level)
Why are inhibitory synapses important?
For slowing the heart rate
balancing the excitatory impulses transmitted to skeletal muscles
prevents excessive contraction
types of neurotransmitters in PNS // CNS
PNS: Ach, NE, Epi
CNS: Dopamine, GABA, NE/Epi, Glutamate, Serotonin, Substance P
Within the CNS, a bundle of pathway axons is called a BLANK (white matter)? In PNS?
CNS: Tract
PNS: Nerves (ex. spinal nerves/cranial nerves)
Where do neurons exit in different spinal regions?
C1-C7 exit OVER corresponding vertebrae
C8 exits below C7 (no C8 vertebrae)
T1-S5 and coccyx exit below
If you do not know where your limbs are in space and can’t use sensory receptors to send information, could be injury in which root?
Dorsal (afferent/sensory)
what are the optimal spots for reflex testing?
Biceps
Brachioradialis
Triceps
patellar
Achilles
Classification of reflexes
- development
-innate reflex or acquired reflex - response
-somatic (deep or superficial) or autonomic (visceral) - complexity
-monosynaptic (somatic, stretch reflex) or polysynaptic (visceral) - processing site
-Spinal cord reflex
-Cranial reflex
Muscle tone and efferent nerves
If efferent nerve is damaged/severed, the muscle will be flaccid/hypotonic
If efferent nerve is continuously stimulated (no inhibition) the muscle will be hypertonic (spastic)
Polysynaptic reflex example:
Withdrawal reflex (painful stimulus to foot, plantar surface)
-multiple interneurons (stimulatory and inhibitory)
-stimulates the hamstring to contract, inhibits the quadriceps from contracting
Why is prescribing medication to a poor metabolizer dangerous?
Meds can buildup in the body
What general factors might induce or inhibit metabolic enzyme systems, particularly CYP 450
Meds, food, and diet supplements
Phase I of drug metabolism (CYP 450)
CYP 450 enzymes carry out oxidation, hydrolysis, or reduction to convert non-polar, lipid-soluble meds into more polar, water-soluble metabolites (preparing for excretion)
Phase II
Conjugation reactions (joined with another compound, like methyl group, acetyl group, etc.)
creating highly polar, water-soluble metabolites that are trapped in urine and excreted
T or False: Phase I and Phase II can occur together, in either order, or separate (not necessarily both need to occur)
T
CYP 450 inhibition example: Warfarin
CYP 450 inhibitors (ex. grapefruit juice) can block the metabolism of Warfarin and cause buildup in the blood
Since warfarin is an anti-coagulant, this can cause severe bleeding
Clarification about myocyte action potential
When the charge inside the cell reaches about +20, and Phase 1 aka initial depolarization occurs, K+ ions leave the cell while calcium ions rush in. Calcium ions are responsible for initiating and maintaining contraction of the heart, so the K+ ions can be thought of as a counterweight to the Ca2+ ions to maintain a heart beat
