W 6 : Muscular System

Question 1

List the functions of skeletal muscle

Answer 1

• pull on bones for movement, bone density
• body posture, stabilise joints
• generate heat
• glycemic control
• venous and lymph flow
• protect organs
• some sphincters (voluntary)

Question 2

name the two regulatory proteins that block the myosin heads from binding to the actin filaments within the sarcomere

Answer 2

• troponin
• tropomyosin

Question 3

Cardiac muscle also utilises actin, myosin, troponin and tropomyosin for muscle contraction. Linda’s father suffers from an apparent heart attack and is rushed off to the emergency room of the local hospital. The doctor tells her that he has ordered some blood work and he will be able to determine whether her father has had a heart attack. why would knowing the blood level of cardiac troponin help to determine this?

Answer 3

• cardiac troponin only found in heart
• evidence of myocardial damage

Question 4

Define neuromuscular junction

Answer 4

site of communication between a neuron and a muscle cell (synapse)

Question 5

Describe the function of a neurotransmitter

Question 6

When acetylcholine (Ash) binds to its receptor on the sarcolemma an electrolyte rushes into the sarcoplasm of the muscle cell which initiates the formation of anew action potential. Name this dominant electrolyte

Question 7

The enzyme acetylcholinesterase breaks down the ACh in the receptor to terminate the stimulation of the muscle so that it can relax. However, many insecticides contain toxins that interfere with the action of this enzyme.

George is using an insecticide and is very careless. Because he is not wearing gloves are a mask, he absorbs some of the chemical through his skin and inhales a large amount as well. Lis some signs would you expect to observe in George because of this poisoning

Answer 7

• ACh not removed
• muscle continues to be stimulated, causing persistent contractions (spastic paralysis)

Question 8

An intramuscular injection deceives a medication into a skeletal muscle

Name two anatomical features of skeletal muscle that make it an effective delivery site

Answer 8

a) big = large dose
b) vascular = fast absorption
less sensitive to irritating and viscous medication

Question 9

State why the nose pulls back the syringe plunger (aspirates) before injecting the medication

Answer 9

ensure needle not in vein (intravenous injection)

Question 10

explain the reason for the nurse to wear gloves when administering an intramuscular injection

Answer 10

contamination with body fluid (blood)

Question 11

Discuss the rationale for active and passive limb exercises in a patient

Answer 11

• maintain muscle mass
• leverage on bones maintains bone density
• facilitate venous and lymph flow
• warm patient up

Question 12

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