which muscle is responsible for breathing

HESI A2

Anatomy HESI A2 Practice Test

1. Which muscle is responsible for breathing?

A. Diaphragm
B. Intercostal muscles
C. Rectus abdominis
D. Pectoralis major

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for breathing. It is a large, dome-shaped muscle located at the base of the chest cavity. When it contracts, it flattens, increasing the volume of the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the volume of the chest cavity and causing exhalation. The intercostal muscles, located between the ribs, assist the diaphragm in breathing by expanding and contracting the chest cavity. The rectus abdominis and pectoralis major are not directly involved in the process of breathing.

2. The vena cavae drain blood from the body into the ___________.

A. right atrium
B. right ventricle
C. left atrium
D. left ventricle

Correct answer: A

Rationale: The vena cavae are large veins responsible for returning deoxygenated blood from the body to the heart. They empty into the right atrium of the heart. From the right atrium, the blood is then pumped into the right ventricle before being sent to the pulmonary circulation for oxygenation, making choice A, 'right atrium,' the correct answer. Choices B, C, and D are incorrect because the vena cavae do not empty into the ventricles of the heart; instead, they deliver blood to the atria.

3. How does the circulatory system work with the digestive system?

A. The circulatory system removes undigested solids from the body.
B. The circulatory system filters and collects digested materials.
C. The circulatory system moves absorbed nutrients through the body.
D. The circulatory system releases enzymes that control digestion.

Correct answer: C

Rationale: The circulatory system works with the digestive system by transporting absorbed nutrients through the body. After digestion occurs in the digestive system, nutrients are absorbed into the bloodstream. The circulatory system then carries these nutrients to cells throughout the body where they are used for energy, growth, and repair. This process ensures that the necessary nutrients are delivered to where they are needed in the body. Choices A, B, and D are incorrect because the circulatory system is not responsible for removing undigested solids, filtering and collecting digested materials, or releasing enzymes that control digestion. These functions are primarily carried out by the digestive system.

4. Which fibrous connective tissue attaches muscles to bones?

A. Tendons
B. Ligaments
C. Cartilage
D. Fascia

Correct answer: A

Rationale: Tendons are fibrous connective tissues that attach muscles to bones, allowing the transmission of forces generated by muscles and facilitating movement at joints. Ligaments, on the other hand, connect bones to other bones, providing stability. Cartilage is a firm, flexible connective tissue found in joints and the respiratory tract. Fascia surrounds muscles, groups of muscles, blood vessels, and nerves, offering support and protection. Therefore, the correct answer is tendons as they specifically connect muscles to bones.

5. Which type of blood vessel carries blood away from the heart?

A. Veins
B. Arteries
C. Capillaries
D. Nerves

Correct answer: B

Rationale: Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls to withstand the high pressure generated by the heart's contractions, ensuring efficient transport of blood throughout the body. Veins, on the other hand, carry deoxygenated blood back to the heart, while capillaries facilitate the exchange of nutrients, oxygen, and waste products between the blood and tissues. Nerves are not involved in the transport of blood.