5.7 Flashcards
In What ads are muscle fibers uniquely adapted for contraction?
Muscle fibers are composed of specialized proteins called actin and myosin, which are arranged into microfilaments. Contraction, or shortening, of the muscle cell occurs when the microfilaments slide over one another like the bars in an old- fashioned slide rule. In this way, the cells change shape and can be made shorter or longer.
List three types of muscle. How do they differ from one another?
Skeletal Muscle:
* Appearance: Striated (banded).
* Control: Voluntary (consciously controlled).
* Function & Location: Moves bones and supports body movement; attached to the skeleton.
Smooth Muscle:
* Appearance: Non-striated, spindle-shaped cells.
* Control: Involuntary (not consciously controlled).
* Function & Location: Found in the walls of internal organs (e.g., intestines, blood vessels) to regulate movement and flow.
Cardiac Muscle:
* Appearance: Striated with branching cells connected by intercalated disks.
* Control: Involuntary with intrinsic pacemaker activity.
* Function & Location: Located only in the heart, generating the rhythmic contractions that pump blood.
What are the two basic cell types that make up neutral tissue?
Two basic types of neural tissue are neurons and supporting neuroglial cells.
What is the most important function of neutral tissue?
The most important function of neural tissue is to receive and transmit electrical and chemical signals throughout the body.
Describe the process of inflammation. What causes the clinical signs of heat, swelling, redness, and tenderness?
- Initial Vasoconstriction: A brief narrowing of small vessels helps control bleeding.
- Vasodilation: Histamine and heparin released from mast cells cause the blood vessels to widen. This increases blood flow, leading to redness and heat.
- Increased Permeability: The dilated capillaries allow plasma (rich inproteins, enzymes, and antibodies) to leak into the tissue, causing swelling.
- Nerve Irritation: The swelling irritates nearby nerve endings, resulting in tenderness or pain
- Clot Formation & Immune Response: Platelets aggregate and form a clot, while white blood cells (like neutrophils and macrophages) migrate to clear debris and pathogens.
What is granulation tissue? Why is it important in the healing process?
- Granulation tissue is a bright pink tissue that forms beneath a scab as part of the healing process. It consists of collagen fibers produced by fibroblasts and is densely packed with new, permeable capillaries that supply nutrients and oxygen. This tissue is important because it supports cell activity for repair, provides a foundation for new tissue growth, and produces substances that inhibit bacterial infection.
When does the healing process begin?
Healing begins with inflammation.
Describe first- and second-intention wound repair
First-Intention Repair:
* Wound edges are closely approximated (e.g., by suturing or bandaging).
* Healing occurs directly with minimal granulation tissue and little scarring.
Second-Intention Repair:
* Wound edges remain separated, so healing relies on granulation tissue formation, contraction, and epithelialization.
* Results in more extensive scarring
