Exam IV: Musculoskeletal Diseases

Question 1

Skeletal Muscle

Answer 1

voluntary control and striated

Question 2

Smooth Muscle (most internal organs) but not the heart

Answer 2

involuntary autonomic control and nonstriated

Question 3

cardiac muscle

Answer 3

intrinsic pacemaker - autonomic nervous system and striated

Question 4

The force generated dependant on intracellular _____ and activation of _____ and _____ filaments

Answer 4

calcium
actin and myosin

Question 5

Skeletal Muscle Include:
(voluntary control; striated)

Answer 5

Muscles of the tongue and soft palate
Extrinsic eye muscles
Muscles that move the scalp
All muscles attached to the skeleton
Muscles of pharynx
Muscles of upper 1/3 of esophagus
Lips * Anus* - serve as sphincters

Question 6

Skeletal Muscle - Innervated by myelinated efferent motor nerve fibers to make _____ ____ _____

Answer 6

alpha motor neurons

Question 7

At the muscle, divides into branches and ends on individual muscle cells called “____ _____.”

Answer 7

muscle fibers

Question 8

Motor unit = 1 motor neuron + ____ ____ in it

Answer 8

all fibers

Question 9

When motor nerve fires, all _____ in motor unit contract at the ___ ____.

Answer 9

fibers
same time

Question 10

Acetylcholine (Ach)

increased Ca++ that comes in…. ____________

Answer 10

increased ACh that is released

Question 11

Acetylcholine (Ach)

150-200 _____ _____ (_____) released with each nerve impulse

Answer 11

ACh vesicles (quanta)

Question 12

Acetylcholine (Ach)

Each _____ has 10, 000 molecules of Ach

Answer 12

quantum

Question 13

Acetylcholine (Ach)

Big ____ _____ — lots of ACh and many receptors available

Answer 13

safety margin

Question 14

Aminoglycoside and Polymyxin antibiotics —- _____ ______ ______

Answer 14

inhibit ACh release

Question 15

Lambert Eaton syndrome –

Answer 15

associated with small cell carcinoma of lung; autoimmune derangement in presynaptic Ca++ channels ; decreases Ach release

Question 16

Botulinum toxin (clostridium botulinum) inhibit ACh release causing ____ ____

Answer 16

flaccid muscle

Question 17

Mg++ competes with Ca++ at voltage-gated channel; ____ ____ release

Answer 17

decreases ACh

Question 18

Calcium Channel Blockers block Ca++ conductance mostly through ____ ____ _____ in heart

Answer 18

“slow” (L) channels

Question 19

ACh Receptor—–Post junctional

NMJ - each has estimated 50 million tightly packed _____ _____ sites

Answer 19

nicotinic AChR

Question 20

ACh Receptor—–Post junctional

Located at crests of ____ ____ ____ ____ folds

Answer 20

motor end plate junctional

Question 21

ACh Receptor—–Post junctional

Made in the _____ cells and then pushed to the end plate membrane and ______ face protrudes a bit

Answer 21

muscle
junctional

Question 22

ACh Receptor—–Post junctional

Activation requires ________ ACh binding at each of the alpha subunits

Answer 22

SIMULTANEOUS

Question 23

ACh Receptor—–Post junctional

Once occupied, cation channel will open, increased conductance to + ions (especially Na+) = ________________________

Answer 23

a net depolarizing potential (EPP)

Question 24

ACh Receptor—–Post junctional

If one ACh molecule leaves the subunit the channel _____ and _____ stops and membrane resets or repolarizes

Answer 24

closes
current

Question 25

WAR at alpha subunit-KING OF THE HILL!

Cholinergic agonist (ACh) VS receptor antagonist (NDMR)

Answer 25

transmission vs blockade

Question 26

WAR at alpha subunit-KING OF THE HILL!

All dependent on concentration of ____ and concentration/binding properties of _____

Answer 26

ACh
antagonist

Question 27

Drugs that block the ACh receptor at the NMJ
Curare-like muscle relaxants:

Answer 27

vecuronim
pancuronium
cisatracurium
rocuronium

Question 28

Drugs that inactivate acetylcholinesterase
Muscle relaxant reversal agents (Compete with ACh for a subunit binding sites):

Answer 28

neostigmine
edrophonium
pyridostigmine

ACh not hydrolyzed so it increases quantity of ACh at synapse
Used to reverse muscle relaxants -
*also used to treat myasthenia gravis

Question 29

Cholinergic receptors ______, too

Answer 29

prejunctionally

Question 30

Prejunctional Receptors

Thought that they may _____ neurotransmitter movement and release

Answer 30

enhance

Question 31

Prejunctional Receptors

Antagonist effects at prejunctional area = decrease in release of ____ leading to _____

Answer 31

ACh
FADE

Question 32

Prejunctional Receptors

Fade (with tetany and train of four) may be reflecting the blockade of prejunctional receptors by the _____ and ACh release is not fast enough to keep up with _____ _____

Answer 32

NDMR
rapid stimulation

Question 33

Acetylcholinesterase

Rapidly hydrolyzes ACh to _____ + _____ in the junctional cleft

Answer 33

choline + acetate

Question 34

Acetylcholinesterase

Choline back into prejunctional nerve terminal to make ____ ____

Answer 34

new ACh

Question 35

Acetylcholinesterase

Reversal of NDMR (neostigmine, etc)-
ANTI CHOLINESTERASE-inhibits breakdown of ACh and increases the amount of ACh at the NMJ —->

Answer 35

*Agonist (ACh) >antagonist (NDMR); transmission restored

Question 36

Acetylcholinesterase

Pseudocholinesterasen- also hydrolyzes ACh; metabolizes ____ _____ and _____

Answer 36

ester LA and Succinylcholine

Question 37

Extrajunctional Receptors (EJR)

In utero— _____ _____ _____. Muscle cells have EJRs and are over entire length of muscle cell. (yAChR and alpha7 subunits)

Answer 37

no muscle innervation

Question 38

Extrajunctional Receptors (EJR)

___ ____, nerve-muscle contact fully mature — ACh receptors only in NMJ; EJRs disappear from ______ part of muscle

Answer 38

Age 2
peripheral

Question 39

Extrajunctional Receptors (EJR)

If neural activity ____ or _____ — muscle goes back to fetal like synthesis of yAChR and alpha 7 receptors (stroke, spinal cord transection, burn, direct muscle damage, prolonged immobility)

***Can develop with ____ _____ from “injury”. Can also return to normal

Answer 39

decreased or removed
48 hours

Question 40

Extrajunctional Receptors (EJR)

EJR – resistant to NDMR, _____ _____ required

Answer 40

large doses

Question 41

Extrajunctional Receptors (EJR)

EJR — more sensitive to ACh, _____ causes channel to stay open, Na into cell and K+ out

Answer 41

succinylcholine

Question 42

EJR—more sensitive to ACh, succinylcholinechannel stays open, Na into cell and K+ out

**No Sux (even as low as _____) with these type of patients—dangerous _____
**Hyper-K+ because prolonged ______ and too much ____ out

Answer 42

20mg
hyper-K+
depolarization
K+