Problem 10 - Biology Today and Tomorrow with Physiology

Question

_________________ muscle tissue has a striated appearance. a. Skeletal c. Cardiac b. Smooth d. a and c

Step-by-Step Solution

Answer

Option d ('a and c') is correct; both skeletal and cardiac muscle are striated.

Step 1: Identify the Keyword

The keyword in the question is "striated appearance." This refers to the visible stripes or bands within the muscle tissue when viewed under a microscope.

Step 2: Understand the Muscle Types

There are three main types of muscle tissue: skeletal, cardiac, and smooth. It's important to recall that smooth muscle lacks striations, whereas both skeletal and cardiac muscles have a striated appearance.

Step 3: Match the Features to the Options

Given that skeletal and cardiac tissues have striations, we need to identify which option correctly lists these. Option a is skeletal and option c is cardiac.

Step 4: Select the Correct Answer

Since both skeletal and cardiac muscle tissues are striated, the correct choice must include both of these options. Therefore, option d ('a and c') is the appropriate answer.

Key Concepts

Skeletal Muscle

Skeletal muscles are vital for voluntary movements. Whenever we decide to move a part of our body, skeletal muscles spring into action. These muscles work closely with the skeleton to help us with actions like walking, running, and grasping objects. One unique feature of skeletal muscle is their striated appearance. These striations are visible under a microscope and result from the organized arrangement of proteins called actin and myosin.

Skeletal muscles are under conscious control, meaning we can decide when and how to move them. They are attached to bones by tendons and are responsible for executing quick and forceful movements.

• Skeletal muscles are voluntary.
• They have a striated appearance.
• They connect to bones and aid in movement.

Despite their ability to generate strong contractions, skeletal muscles tire easily and need rest after extensive use.

Cardiac Muscle

Cardiac muscles make up the walls of the heart. They have a striated appearance similar to skeletal muscles, but with unique features that differentiate them. One such feature is intercalated discs. These are special connections that allow for rapid signaling between cardiac cells, ensuring that the heart beats in a coordinated manner.

Unlike skeletal muscles, cardiac muscles are not under voluntary control. The autonomic nervous system automatically regulates their function. This ensures our heart continues to pump blood throughout the body without us having to think about it.

• Cardiac muscles are involuntary.
• Striations are present, like in skeletal muscles.
• Contain intercalated discs for synchronized contraction.

The endurance of cardiac muscle is remarkable, tirelessly beating night and day to maintain circulation.

Smooth Muscle

Smooth muscles lack the striations seen in skeletal and cardiac muscles. This means they appear smooth when viewed under a microscope. These muscles can be found in many parts of the body and are responsible for involuntary actions.

Unlike skeletal and cardiac muscles, smooth muscles work in organs such as the stomach, intestines, and blood vessels. They help manage functions like moving food through the digestive tract and regulating blood pressure.

• Smooth muscles are involuntary and non-striated.
• Located within walls of organs and vessels.
• Crucial for life-sustaining functions.

Smooth muscles work slowly and sustain contractions for extended periods, making them essential for the body's ongoing processes without tiring quickly.