Skeletal Muscle Cells Overview

Study Notes

Skeletal Muscle

Skeletal muscle fibers maintain a constant number throughout life; they do not undergo mitosis due to their structure.
Individual skeletal muscle fibers can increase or decrease in size but not in number.
Skeletal muscle cells are long, multinucleated, and organized into bundles surrounded by connective tissue.
Under light microscopy, skeletal muscle appears striated with peripheral nuclei.

Cardiac Muscle

Cardiac muscle forms the walls of the heart and consists of cardiomyocytes.
Cardiomyocytes are smaller than skeletal muscle fibers and contain a single, centrally located nucleus.
Specialized junctions called intercalated discs connect cardiomyocytes, featuring desmosomes and gap junctions.
Cardiac muscle is under involuntary control and pumps blood throughout the body.

Smooth Muscle

Smooth muscle tissue facilitates involuntary movements in internal organs (digestive, urinary, reproductive systems) as well as airways and arteries.
Smooth muscle cells are football-shaped, possess a single nucleus, and lack visible striations.

Nervous Tissue

Nervous tissue comprises the brain, spinal cord, and peripheral nerves and exhibits excitability.
Two primary types of cells in nervous tissue: neurons (signal transmitters) and glial cells (supportive cells).
Neurons communicate via electrochemical impulses known as action potentials, triggering the release of signaling molecules.

Neuron Structure

Neurons consist of three main parts:
- Cell body: Contains organelles and nucleus.
- Dendrites: Short branches that receive signals from other cells.
- Axon: A long projection that transmits signals to other cells.

Tissue Membranes

Membranes may refer to cell membranes or tissue membranes, which are thin sheets of cells that cover various body structures.
Four types of tissue membranes: mucous, serous, cutaneous, and synovial.

Mucous Membranes

Composed of connective and epithelial tissues, mucous membranes line cavities and passageways that open to the outside environment, such as the digestive and respiratory tracts.

Serous Membranes

Serous membranes line internal cavities that do not open to the exterior, secreting serous fluid for lubrication to reduce friction between organs.

Cutaneous Membrane

The skin is the cutaneous membrane, a stratified squamous epithelium over connective tissue, providing a barrier against environmental factors.

Synovial Membranes

Synovial membranes are connective tissues that line the cavities of movable joints, releasing synovial fluid for lubrication and nourishment of cartilage.

Inflammation

Inflammation is the body's initial response to injury, with acute inflammation resolving over time through healing.
Chronic inflammation can adversely affect homeostasis, with arthritis and tuberculosis as examples.
The suffix "-itis" indicates inflammation of a specific organ or type.

Description

Explore the unique characteristics and structure of skeletal muscle cells, also known as skeletal muscle fibers. This quiz delves into their multinucleated nature, arrangement in bundles, and how they differ from other muscle types. Test your knowledge on the physiology of skeletal muscles.