(1) Neuromuscular (NM).doc

JC1 - 2010 M1Neuromuscular

MCQs

The dura in the spinal canal NM1 SLIDE 33 A. extends as far as the coccyx B. lies anterior to the posterior longitudinal ligament C. is a delicate waterproof membrane D. is surrounded by the internal vertebral venous plexus E. is the deepest layer of the meninges ANSWER: D Concerning cerebrospinal fluid (CSF): NM1 SLIDE 37 A. CSF pressure is normally 10 mmHg B. most of the CSF is found in the ventricles C. a normal sample of CSF is pale yellow D. the glucose concentration in a normal sample of CSF is greater than that of plasma E. CSF is formed by diffusion of ions and water across the walls of the cerebral capillaries ANSWER: B Transmission of the nerve impulse: NM2 SLIDE 20 A. excitatory neurotransmitters open sodium channels B. excitatory neurotransmitters hyperpolarize the membrane C. opening of chloride channels results in depolarisation of the nerve cell membrane D. is saltatory in unmyelinated fibres E. conduction velocity is inversely proportional to the diameter of the axon ANSWER :A All of the following statement about voltage-gated sodium channels are true except: NM2 SLIDE 31 A. Channel opening / closing is regulated by membrane potential changes B. Channels are opened at a more negative range of potentials than most calcium channels C. When the membrane is polarized, the voltage gate is closed, and the activation gate is open D. When the membrane is depolarized, the voltage gate opens E. When the membrane depolarizes, the voltage gate closes, resetting the activation gate. ANSWER: E The action potential is associated with: NM2 SLIDE 31 A. a sudden increase in membrane permeability to sodium B. a decrease in membrane permeability to calcium C. an increase in membrane permeability to chloride D. a decrease in membrane permeability to potassium E. no change in membrane permeability to cations ANSWER: A Concerning the nerve impulse: NM2 SLIDE 36 A. excitatory neurotransmitters open potassium channels

B. excitatory neurotransmitters hyperpolarize the membrane C. Nodes of Ranvier contain mainly sodium channels D. glycine is usually an excitatory neurotransmitter E. acidosis increases neuronal excitability ANSWER: C Which ONE of the following is correct regarding transmission of the nerve impulse: NM2 SLIDE 46 A. excitatory neurotransmitters open potassium channels B. excitatory neurotransmitters hyperpolarize the membrane C. nodes of Ranvier contain mainly sodium channels D. glycine is usually an excitatory neurotransmitter E. acidosis increases neuronal excitability ANSWER: C A-50-year old woman presents with abnormal sensory feelings, double vision in the right eye, and muscle weakness in her extremities. Neurological examination was performed and the diagnosis of multiple sclerosis was suspected. Which of the following is the most likely cause for the patient’s symptoms? NM2 SLIDE 48 A. demyelination of motor and sensory nerve fibers B. decreased conduction velocity of action potentials in unmyelinated nerve fibers C. decreased conduction velocity of action potentials along the sarcolemma D. decreased synaptic delay at the neuromuscular junction E. decreased acetylcholine esterase activity at the neuromuscular junction ANSWER: A Which statement is WRONG: NM3 SLIDE 26 A. extracellular sodium (Na+) concentration is higher than the intracellular Na+ concentration. B. intracellular potassium (K+) concentration is higher than the extracellar K+ concentration. C. intracellular chloride (Cl-) concentrations is similar to the extracellular Clconcentration. D. permeability of biological membranes for Na+ and Cl- is lower than the permeability for K+. E. the Na-K-pump consumes ATP to generate stable ion gradients in cells. ANSWER: C The resting membrane potential: NM3 SLIDE 33 A. Is approx. –70 mV in neurons B. Arises because ion concentrations are equal across the membrane C. Is equal to the potassium equilibrium potential D. Is equal to the sodium equilibrium potential E. Is made positive by background sodium current ANSWER: A All living cells develop a potential across their cell membranes. What is the approximate equilibrium potential of Na+ using Nernst equation? NM3 SLIDE 43 A. -90 mV

B. -20 mV C. +70 mV D. -110 mV E. +35 mV ANSWER: C The fascia lata NM4 SLIDE 26 A. is readily distensible B. is attached to the inguinal ligament C. is attached to both malleoli D. is pierced by the femoral artery E. is thickest on the medial side of the thigh ANSWER: B The femoral artery NM5 SLIDE 21 A. is a continuation of the internal iliac artery B. enters the thigh by passing superficial to the inguinal ligament C. is the main arterial supply to the lower limb D. lies lateral to the femoral nerve E. has branches, all of which lie deep to the deep fascia of the thigh ANSWER: C All the following are true of the femoral artery EXCEPT: NM5 SLIDE 23 A. it is palpable below the mid point of the inguinal ligament B. it lies lateral to the femoral vein in the femoral sheath C. it runs in the subsartorial canal D. it gives off the profunda femoris from its medial side E. it supplies the leg ANSWER: D The sciatic nerve: NM6 SLIDE 32 A. has roots L3,4,5, S1,2,3,4 B. has the saphenous nerve as a branch C. exits the greater sciatic foramen above piriformis D. injury may result in foot-drop E. gives the inferior gluteal as a branch ANSWER: D Spina bifida is the most common form of neural tube defect. The neural tube is formed from NM8 SLIDE 5 A. ectoderm B. mesoderm C. endoderm D. the notochord E. neural crest cells ANSWER: A All the following are true of the hip joint EXCEPT: NM9 A. it is synovial B. it is penetrated by the ligament of the head of the femur

C. it is abducted by gluteus maximus D. it is supplied by the femoral nerve E. it is unlikely to dislocate ANSWER: C Capsule of the hip joint is attached to NM9 SLIDE 6 A. the greater trochanter B. the lesser trochanter C. both the greater and lesser trochanters D. the intertrochanteric line E. the intertrochanteric crest ANSWER: D The common peroneal nerve is at risk of injury in fractures of the neck of the fibula. That nerve is a branch of the NM9 SLIDE 33 A. sciatic nerve B. lumbosacral trunk C. femoral nerve D. sural nerve E. obturator nerve ANSWER: A Fatima Al-Attar, a 29-year-old hotel receptionist, has been diagnosed with myasthenia gravis. She first noticed that something was wrong three months ago, when she developed ptosis. Ptosis is NM10 SLIDE 36 A. difficulty in swallowing B. double vision C. shortness of breath D. difficulty in speaking E. drooping of the eyelids ANSWER: E Concerning autonomic neurotransmission: NM12/13 SLIDE 10 A. noradrenaline constricts the pupil B. adrenaline is the neurotransmitter at somatic nerve endings C. acetylcholine stimulates release of catecholamines from the adrenal medulla D. noradrenaline stimulates gastric acid secretion E. adrenaline acts on the bladder to cause micturition ANSWER: C The patient has normal autonomic nervous system function. Normally, in the autonomic nervous system which ONE of the following statements is correct? NM12/13 SLIDE 10 A. noradrenaline constricts the pupil B. adrenaline is the neurotransmitter at somatic nerve endings C. acetylcholine stimulates release of catecholamines from the adrenal medulla D. noradrenaline stimulates gastric acid secretion E. adrenaline acts on the bladder to cause micturition ANSWER: C

The neurotransmitter at the parasympathetic neuroeffector junction is: NM12/13 SLIDE 14 A. acetylcholine B. adrenalin C. dopamine D. noradrenalin E. serotonin ANSWER: A In autonomic ganglia, the neurotransmitter released from the presynaptic nerve terminal is: NM12/13 SLIDE 14 A. noradrenaline B. adrenaline C. acetylcholine D. glycine E. substance P ANSWER: C Stimulation of the sympathetic nervous system results in: NM12/13 SLIDE 33 A. pupillary constriction B. slowing of atrioventricular conduction C. vasoconstriction D. skeletal muscle contraction E. inhibition of renin release ANSWER: C A 19-year-old soccer player injures his knee during a match. He is placed supine on an examination couch with the knee flexed. The doctor who examines him sits on the player’s foot to immobilise it, and finds that he can easily pull the tibia forwards. He concludes from this that the player has most likely injured his NM14 SLIDE 16 A. medial collateral ligament B. lateral collateral ligament C. medial meniscus D. anterior cruciate ligament E. posterior cruciate ligament ANSWER: D The right knee NM14 SLIDE 19 A. has intrasynovial cruciate ligaments B. is locked in extension by popliteus C. is flexed by the soleus muscle D. has a suprapatellar bursa which communicates with the joint cavity E. has its lateral collateral ligament adherent to the lateral meniscus ANSWER: D **The vascular system in a 43-year-old accountant with long-standing diabetes mellitus is being assessed. There are no palpable pulses below his right knee. The dorsalis pedis pulse is normally felt NM15 SLIDE 28 A. medial to the extensor hallucis longus tendon

B. distal to the flexor retinaculum of the ankle C. behind the lateral malleolus D. in the cleft between the first and second toes E. by gently pressing the artery against the lateral cuneiform bone ANSWER: B Intervertebral discs NM17 SLIDE 26 A. are found in all regions of the vertebral column B. have a central part of hyaline cartilage C. may compress the lumbar segments of the spinal cord in a larger posterior herniation D. tend to herniate posterolaterally due to pressure by the ligamenta flava E. frequently herniate anteriorly ANSWER: C Hypertension (high blood pressure) may be treated with: NM19 SLIDE 39 A. beta1 adrenergic receptor antagonism B. beta2 adrenergic receptor agonism C. muscarinic1 receptor antagonism D. muscarinic 2 receptor antagonism E. muscarinic2 receptor agonism ANSWER: A Acetylcholinesterase inhibitors in excess can cause the following adverse effect: NM20 SLIDE 21 A. tachycardia B. excess hair growth C. increased intra-ocular pressure (glaucoma) D. skeletal muscle weakness or paralysis E. high blood pressure ANSWER: D A 35 year old woman presents with skeletal muscle weakness. Neuromuscular transmission is abnormal and a diagnosis of myasthenia gravis is established. Her symptoms are improved by administration of pyridostigmine. The mechanism of action of pyridostigmine is that it: NM20 SLIDE 25 A. increases post-synaptic receptor density B. increases quantal release of acetylcholine C. enhances calcium availability D. is a non-depolarising neuromuscular blocker E. inhibits acetylcholinesterase ANSWER: E A biopsy of the quadriceps muscle of an elite 100 m sprinter shows that the majority of the muscle fibres are type 2b. Compared to type 1 fibres, type 2b fibres are: NM22 SLIDE 19 A. smaller in diameter B. produce less isometric tension C. contain more myoglobin D. contain more mitochondria

E. contain more glycogen ANSWER: E Compared to type II fibres, type I fibres have which ONE of the following: NM22 SLIDE 20 A. shorter sarcomeres B. smaller diameters C. less myoglobin D. less mitochondria E. more myosin ANSWER: B Compared to type II fibres, type I fibres have which ONE of the following: NM22 SLIDE 20 A. shorter sarcomeres B. smaller diameters C. less myoglobin D. less mitochondria E. more myosin ANSWER: B Hypertrophy of type II fibres occurs with: NM22 SLIDE 21 A. peripheral neuropathies B. bed rest C. myasthenia gravis D. weight training E. limb immobilization ANSWER: D Concerning calcium in cardiac muscle, which ONE of the following statements is correct: NM22 SLIDE 32 A. its release from the sarcoplasmic reticulum is by active transport B. it enters the cell during the action potential C. its reuptake into the sarcoplasmic reticulum is by passive diffusion D. it binds to actin E. it binds to myosin ATPase ANSWER: B Tetanic contraction in skeletal muscle is caused by which ONE of the following, choose one answer: NM23 SLIDE 20 A. Decreased preload B. Stretching beyond optimal length C. Increased afterload D. Treppe or staircase phenomenon E. High frequency stimulation ANSWER: E During isometric contractions: NM23 SLIDE 29 A. maximal cross-bridge formation occurs at optimal length B. the contractile element lengthens

C. the series elastic element shortens D. muscle tension is independent of initial fibre length E. the actin filaments shorten ANSWER: A During isometric contractions: NM23 SLIDE 29 A. maximal cross-bridge formation occurs at optimal length B. the contractile element lengthens C. the series elastic element shortens D. muscle tension is independent of initial fibre length E. the actin filaments shorten ANSWER: A Electromyography is a technique which measures: NM24 SLIDE 17 A. electrical activity in heart muscle B. skeletal muscle tension C. electrical activity in skeletal muscle D. skeletal muscle length E. electrical activity in smooth muscle ANSWER: C Obstetricians calculate the duration of a pregnancy A. from the date of the last occurrence of sexual intercourse B. from the first day of the last menstrual period C. by subtracting two weeks from the time elapsed since the start of the last menstrual period D. as 36 weeks E. as 38 weeks ANSWER: B After acute severe blood loss: A. peripheral resistance is the main determinant of central venous pressure B. blood volume is ideally replaced by transfusion of group O rhesus positive blood C. capillary fluid shift contributes to restoration of blood volume D. urine output remains above 1ml/kg/hour E .decreased tissue perfusion results in metabolic alkalosis ANSWER: C One of the tendon reflexes which the doctor tested was the knee jerk response. The knee jerk response: A. is elicited by tapping the patella B. involves contraction of the quadriceps femoris muscle and simultaneous contraction of the hamstrings C. involves stretch of the spindles of the quadriceps femoris muscle D. involves stretch of the spindles of the hamstrings E. was normal in this woman because the knee jerk response does not involve neuromuscular transmission ANSWER: C