
Concept explainers
Which of the following classes of muscle is/are voluntary?
a. skeletal muscle
b. cardiac muscle
c. smooth muscle
d. all of the above

Introduction:
The muscles that are controlled by the external stimulation are called as voluntary muscles. The muscles that are not under voluntary control are called as involuntary muscles.
Answer to Problem 1TYK
Correct answer:
The skeletal muscles fall under the class of voluntary muscles. The skeletal muscles make up the skeletal system of the body. It consists of long, unbranched fibers.
Explanation of Solution
Explanation/Justification for the correct answers:
Option (a) is given as skeletal muscle. The presence of sarcomeres in the muscle cell give them a striated appearance. These muscles can be controlled by the somatic motor neurons and hence, are voluntary in nature. Hence, Option (a) is correct.
Explanation for incorrect answer:
Option (b) is given as cardiac muscle. The muscles that line the walls of the heart and are responsible for pumping blood throughout the body are known as cardiac muscles. The highly branched cardiac muscles are joint end-to-end by the intercalated discs. The electrical signals flow across these intercalated discs and thus coordinate the heartbeats. The cardiac muscles are involuntary in nature as they are not controlled by external stimulation. So, it is incorrect.
Option (c) is given as smooth muscle. Organs like the lungs, blood vessels, reproductive system, urinary bladder, and digestive system are made up of smooth muscles. These muscles show no branching and taper towards the ends. The absence of sarcomeres in the cells give them a smooth appearance. The autonomous motor neurons run across these muscles and hence they are involuntary in nature. So, it is incorrect.
Option (d) is given as all the above. The smooth muscles and the cardiac muscles are involuntary in nature, therefore all of the above cannot be chosen as an option. So, it is incorrect.
Hence, options (b), (c), and (d) are incorrect.
The skeletal muscles are voluntary, whereas the smooth muscles and the cardiac muscles are involuntary in nature.
Want to see more full solutions like this?
Chapter 45 Solutions
Biological Science (6th Edition)
- You intend to insert patched dominant negative DNA into the left half of the neural tube of a chick. 1) Which side of the neural tube would you put the positive electrode to ensure that the DNA ends up on the left side? 2) What would be the internal (within the embryo) control for this experiment? 3) How can you be sure that the electroporation method itself is not impacting the embryo? 4) What would you do to ensure that the electroporation is working? How can you tell?arrow_forwardDescribe a method to document the diffusion path and gradient of Sonic Hedgehog through the chicken embryo. If modifying the protein, what is one thing you have to consider in regards to maintaining the protein’s function?arrow_forwardThe following table is from Kumar et. al. Highly Selective Dopamine D3 Receptor (DR) Antagonists and Partial Agonists Based on Eticlopride and the D3R Crystal Structure: New Leads for Opioid Dependence Treatment. J. Med Chem 2016.arrow_forward
- The following figure is from Caterina et al. The capsaicin receptor: a heat activated ion channel in the pain pathway. Nature, 1997. Black boxes indicate capsaicin, white circles indicate resinferatoxin. You are a chef in a fancy new science-themed restaurant. You have a recipe that calls for 1 teaspoon of resinferatoxin, but you feel uncomfortable serving foods with "toxins" in them. How much capsaicin could you substitute instead?arrow_forwardWhat protein is necessary for packaging acetylcholine into synaptic vesicles?arrow_forward1. Match each vocabulary term to its best descriptor A. affinity B. efficacy C. inert D. mimic E. how drugs move through body F. how drugs bind Kd Bmax Agonist Antagonist Pharmacokinetics Pharmacodynamicsarrow_forward
- 50 mg dose of a drug is given orally to a patient. The bioavailability of the drug is 0.2. What is the volume of distribution of the drug if the plasma concentration is 1 mg/L? Be sure to provide units.arrow_forwardDetermine Kd and Bmax from the following Scatchard plot. Make sure to include units.arrow_forwardChoose a catecholamine neurotransmitter and describe/draw the components of the synapse important for its signaling including synthesis, packaging into vesicles, receptors, transporters/degradative enzymes. Describe 2 drugs that can act on this system.arrow_forward
- The following figure is from Caterina et al. The capsaicin receptor: a heat activated ion channel in the pain pathway. Nature, 1997. Black boxes indicate capsaicin, white circles indicate resinferatoxin. a) Which has a higher potency? b) Which is has a higher efficacy? c) What is the approximate Kd of capsaicin in uM? (you can round to the nearest power of 10)arrow_forwardWhat is the rate-limiting-step for serotonin synthesis?arrow_forwardWhat enzyme is necessary for synthesis of all of the monoamines?arrow_forward
- Comprehensive Medical Assisting: Administrative a...NursingISBN:9781305964792Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy CorreaPublisher:Cengage LearningMedical Terminology for Health Professions, Spira...Health & NutritionISBN:9781305634350Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. SchroederPublisher:Cengage Learning
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College



