Anatomy and Physiology

Anatomy and physiology

[jennifer-lutz]

The operation of most skeletal muscles involves leverage  – using a lever to move an object. A lever is a rigid bar that moves on a fixed point called the fulcrum, when a force is applied to it.

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Lever Systems: Bone-Muscle Relationships

The operation of most skeletal muscles involves leverage - using a lever to move an object. A lever is a rigid bar that moves on a fixed point called th...

[jennifer-lutz]

A big factor that contributes to muscle force and speed is fascicle arrangement. Other factors such as fiber type, lever systems and load will be discussed in a separate article.

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Muscle Mechanics: Fascicle Arrangement

All skeletal muscle is made up of fascicles (bundles of fiber), but fascicle arrangements vary considerably, resulting in muscles with different shapes a...

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The 206 named bones of the human skeleton are divided into two groups: axial and appendicular.

The axial skeleton forms the long axis of the body and includes the bones of the skull, vertebral column, and rib cage. Generally speaking these bones protect, support, or carry other body parts.

The appendicular skeleton consists of the bones of the upper and lower limbs and the girdles (shoulder bones and hip bones) that attach the limbs to the axial skeleton. Bones of the limbs help us move from place to place (locomotion) and manipulate our environment.

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Function and Classification of Bones

The 206 named bones of the human skeleton are divided into two groups: axial and appendicular. They are further classified by shape. Long, short, flat, i..

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Along with its bones, the skeleton contains resilient cartilages, and although the major focus of this category is skeletal structure and bone tissue, we will briefly discuss the three main skeletal cartilages in this article.

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Skeletal Cartilages

There are three types of skeletal cartilage tissue in the body: hyaline, elastic, and fibrocartilage. The skeletal cartilages include examples from all t...

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Cell junctions: An epithelial cell is shown joined to adjacent cells by three common types of cell junctions.

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Cell Junctions

There are three main types of cell junctions: tight junctions, desmosomes, and gap junctions. Let's take a look at each cell junction individually. Tight...

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The flexible plasma membrane defines the barrier of a cell by separating two of the body’s major fluid compartments – the intracellular fluid within cells and the extracellular fluid (ECF) outside cells. The term cell membrane is commonly used as a synonym for plasma membrane, but in this article we will refer to the cell’s surface as the plasma membrane. The plasma membranes unique permeable structure allows it to play a dynamic role in cellular activities.

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The Plasma Membrane: Structure

The flexible plasma membrane defines the barrier of a cell by separating two of the body's major fluid compartments - the intracellular fluid within cell...

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Cells are the basis of life. Some connect body parts and store nutrients, others fight disease and transport gases. Some cells gather information and control certain body functions, while specialized cells are used for reproduction.

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Cell Theory: The Cellular Basis of Life

Since the late 1800's, cell research has seen astounding gains and provided us with four concepts collectively known as cell theory.

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Covering and lining epithelium- forms the outer layer of the skin; lines open cavities of the digestive and respiratory systems; covers the walls of organs of the closed ventral body cavity.

Glandular epithelium- surrounds glands within the body.

Epithelial Tissue

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Image: Anterior view of the human heart with labels.

Gross Anatomy of the Heart

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Homeostasis: positive/ negative feedback mechanisms