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INTRODUCTION AND
TERMINOLOGY
Anatomy_1_Lecture_Notes DEFINITIONS Anatomy is the study of the structure of the body. Often, you may be more interested in functions of the body. Functions include digestion, respiration, circulation, and reproduction. Physiology is the study of the functions of the body. The body is a chemical and physical machine. As such, it is subject to certain laws. These are sometimes called natural laws. Each part of the body is engineered to do a particular job. These jobs are functions. For each job or body function, there is a particular structure engineered to do it. In the laboratory, anatomy is studied by dissection (SECT = cut, DIS = apart). BODY TYPES No two human beings are built exactly alike, but we can group individuals into three major categories. These groups represent basic body shapes. MORPH = body, body form ECTO = all energy is outgoing ENDO = all energy is stored inside MESO = between, in the middle ECTOMORPH = slim individual ENDOMORPH = broad individual MESOMORPH = body type between the two others, “muscular” type Ectomorphs, slim persons, are more susceptible to lung infections. Endomorphs are more susceptible to heart disease. NOTE ON TERMINOLOGY Each profession and each science has its own language. Lawyers have legal terminology. Physicians and other medical professions and occupations have medical terminology, and educators have objectives, domains, and curricula.
To work in a legal field, you should know the meaning of quid pro quo. To work in a medical field, you should know the meanings of terms such as proximal, distal, sagittal, femur, humerus, thorax, and cerebellum. KINDS OF ANATOMICAL STUDIES Microscopic anatomy is the study of structures that cannot be seen with the unaided eye. You need a microscope. Gross anatomy by systems is the study of organ systems, such as the respiratory system or the digestive system. Gross anatomy by regions considers anatomy in terms of regions such as the trunk, upper member, or lower member. Neuroanatomy studies the nervous system. Functional anatomy is the study of relationships between functions and structures. ORGANIZATION OF THE HUMAN BODY The human body is organized into cells, tissues, organs, organ systems, and the total organism. Cells are the smallest living unit of body construction. A tissue is a grouping of like cells working together. Examples are muscle tissue and nervous tissue. An organ is a structure composed of several different tissues performing a particular function. Examples include the lungs and the heart. Organ systems are groups of organs which together perform an overall function. Examples are the respiratory system and the digestive system. The total organism is the individual human being. You are a total organism.
Head and Neck. The brain, eyes, ears, mouth, pharynx, and larynx are found in this region. Members. Each upper member includes a shoulder, arm, forearm, wrist, and hand. Each lower member includes a hip, thigh, leg, ankle, and foot. ANATOMICAL TERMINOLOGY As I mentioned earlier, you must know the language of a particular field to be successful in it. Each field has specific names for specific structures and functions. Unless you know the names and their meanings, you will have trouble saying what you mean. You will have trouble understanding what others are saying. You will not be able to communicate well. What is a scientific term? It is a word that names or gives special information about a structure or process. Some scientific terms have two or three different parts. These parts are known as a PREFIX, a ROOT (or base), and a SUFFIX. An example is the word subcutaneous. SUBCUTANEOUS means below the skin. SUB means below. SUB is the prefix. CUTIS means skin. CUTIS is the root. A second example is the word myocardium. MYOCARDIUM means the muscular wall of the heart. MYO means muscle. MYO is a prefix. CARDIUM means heart. CARDIUM is the root. A third example is the word tonsillitis. TONSIL is the root ITIS is the suffix and means inflammation. So TONSILLITIS means an inflammation of the tonsils THE ANATOMICAL POSITION
The anatomical position is an artificial posture of the human body (see figure 1-2). This position is used as a standard reference throughout the medical profession. We always speak of the parts of the body as if the body were in the anatomical position. This is true regardless of what position the body is actually in. In the anatomical position, the body stands erect, with heels together. Upper members are along the sides, with the palms of the hands facing forward. The head faces forward.
PLANES OF THE BODY
See figures 1-3A through 1-3C for the imaginary planes used to describe the body. Sagittal planes are vertical planes that pass through the body from front to back. The median or midsagittal plane is the vertical plane that divides the body into right and left halves. Horizontal (transverse) planes are parallel to the floor. They are perpendicular to both the sagittal and frontal planes. Frontal (coronal) planes are vertical planes which pass through the body from side to side. They are perpendicular to the sagittal plane.
Figure 1-3, A. The sagittal plane. Figure 1-3, B. The horizontal plane. Figure 1-3 C. The frontal plane. DIRECTIONS Superior means above. Inferior means below.
A cell is the microscopic unit of body organization. The “typical animal cell” is illustrated in figure 1-4. A typical animal cell includes a cell membrane, a nucleus, a nuclear membrane, cytoplasm, ribosomes, endoplasmic reticulum, mitochondria, Golgi apparatus, centrioles, and lysosomes, and I’ll talk a little about each of them. MAJOR COMPONENTS OF A “TYPICAL” ANIMAL CELL Nucleus. The nucleus plays a central role in the cell. Information is stored in the nucleus and distributed to guide the life processes of the cell. This information is in a chemical form called nucleic acids. Two types of structures
found in the nucleus are chromosomes and nucleoli. Chromosomes can be seen clearly only during cell divisions. Chromosomes are composed of both nucleic acid and protein. Chromosomes contain genes. Genes are the basic units of heredity which are passed from parents to their children. Genes guide the activities of each individual cell. Cell Membrane. The cell membrane surrounds and separates the cell from its environment. The cell membrane allows certain materials to pass through it as they enter or leave the cell. Cytoplasm. The semifluid found inside the cell, but outside the nucleus, is called the cytoplasm. Mitochondria (Plural). Mitochondria are the “powerhouses” of the cell. The mitochondria provide the energy wherever it is needed for carrying on the cellular functions. Endoplasmic Reticulum. The endoplasmic reticulum is a network of membranes, cavities, and canals. The endoplasmic reticulum helps in the transfer of materials from one part of the cell to the other. Ribosomes. Ribosomes are “protein factories” in the cell. They are composed mainly of nucleic acids which help make proteins according to instructions provided by the genes. Centrioles. Centrioles help in the process of cell division. Lysosomes. Lysosomes are membrane bound spheres which contain enzymes that can digest intracellular structures or bacteria CELL MULTIPLICATION (MITOSIS) Individual cells have fairly specific life spans. Some types of cells have longer life spans than others. During the processes of growth and repair, new cells are being formed. The usual process of cell multiplication is called mitosis. There are two important factors to consider: · From one cell, we get two new cells. · The genes of the new cells are identical (for all practical purposes) to the genes of the original cell.
- Nervous tissue, neuron, or
- Name four major types of connective tissue (CT)
- Name the characteristic cells of fibrous CT, cartilage CT, and bone CT
- Describe the matrix of fibrous CT, cartilage CT, and fat
DEFINITION
A tissue is a grouping of like cells working together.
TYPES OF TISSUES
There are several major types of tissues. The most common types are epithelial, connective, muscle, and nervous tissues. Later, this lesson will discuss each type.
TISSUES AND ORGANS
- Tissues make up An organ is a structure performing a particular function. An organ is composed of several different tissues. Examples of organs are the lungs and the heart.
- In some cases, a term may be used to describe both a type of tissue and a kind of organ. For example, we speak of bone tissue and of bones. We speak of muscle tissue and of muscles.
DEFINITION OF EPITHELIAL TISSUES
Epithelial tissue is tissue that covers surfaces and lines cavities. Here, it may protect, absorb, and/or secrete. Epithelial tissue covers the outer surface of the body. It lines the intestines, the lungs, and other hollow organs.
TYPES OF EPITHELIAL CELLS (BY SHAPE)
Figure 2-1 illustrates the basic types of epithelial cells by shape. The three basic shapes are squamous (flat), cuboidal (cubes), and columnar (columns).
TYPES OF EPITHELIAL TISSUES
- Layers. In epithelial tissues, the cells are in single or multiple layers. If there is only one layer, the tissue is called a simple If there is more than one layer, the tissue is called a stratified epithelium. See figure 2-2.
- Naming. Epithelial tissues are named by the number of layers and the type of cell in its outermost For example, if there are several layers and if the outermost layer consists of squamous (flat) cells, then the tissue is called a stratified squamous epithelium.
c. Examples of Epithelial Tissues.
A simple squamous epithelium called endothelium lines the heart and blood As serous membranes, simple squamous epithelial tissue lines the cavities of the abdomen (peritoneal lining) and the chest (pleural lining). Serous membranes are membranes which secrete a lubricating Epithelial tissue forms the secretory part of glands and also parts of the various sense
- Functions. According to its location, epithelial tissue has different functions. As the skin, epithelial tissue protects the tissues beneath. In the small intestines, the epithelial tissue In the lungs, epithelial tissue is a
CARTILAGE CONNECTIVE TISSUE
- Cartilage Cells. Cartilage cells are also called Cartilage cells are clustered in microscopic pockets within the cartilage matrix. The cartilage cells produce the material of the matrix.
- Matrix. The matrix produced by the cartilage cells appears homogeneous (the same throughout). The matrix also appears amorphous (shapeless).
c. Types of Cartilage CT.
Hyaline cartilage Hyaline cartilage CT appears homogeneous and clear. HYALINE = clear This type of cartilage helps to cover bone surfaces at joints. Hyaline cartilage is found as incomplete rings which keep the trachea (windpipe) open. Fibrous cartilage Fibrous cartilage CT includes dense masses of fibers (of FCT). It is more rigid than hyaline cartilage. The auricle of the external ear is stiffened with fibrous cartilage. Calcified cartilage Calcified cartilage CT is cartilage that has been stiffened by the addition of calcium salts. This is not the same as bone tissue. An example is the cartilages of the larynx (the voice box) which become calcified with age.
BONE CONNECTIVE TISSUE
- Osteoblasts/Osteoclasts. Osteoblasts are cells that make and repair bone. Osteoclasts are cells which tear down and remove bone. Bone is continually being remodeled as a person lives. Remodeling is in direct response to the stresses placed on the
- Types of Bone Tissues. There are two major types of bone One is compact bone CT, which is dense. The other is cancellous bone CT, which is spongy. Compact bone CT forms the hard outer layers of bones as organs. Cancellous bone CT forms the inner, lighter portion of bones.
FAT CONNECTIVE TISSUE
- Fat Cells. A large fraction of the volume of a fat cell is occupied by a droplet of fat. This droplet has its own membrane, in addition to the outer membrane of the The remaining components of the fat cell, including the nucleus, are found in an outer layer of cytoplasm surrounding the droplet of fat.
- Matrix. Fat connective tissue has a matrix of lipid (oil or fat). There may be yellow fat CT or brown fat CT.
- Functions. Fat CT acts as a packing material among the organs, nerves, and vessels. Fat CT also helps to insulate the body from both heat and cold. Some fat CT serves as a high-energy storage area.
BLOOD “CONNECTIVE TISSUE”
Some experts consider blood to be a type of connective tissue. Blood will be discussed in lesson 9.
DEFINITION OF MUSCLE TISSUES
There are muscle tissues and there are organs called muscles. Muscles are made up of muscle tissues. Muscle tissues and the muscles they make up are specialized to contract. Because of their ability to shorten (contract), muscles are able to produce motion.
TYPES OF MUSCLE TISSUES
See figure 2-3 for the three types of muscle tissue.
- Skeletal Muscle Tissue. The cells (muscle fibers) of skeletal muscle tissue are long and cylindrical and have numerous The arrangement of the cellular contents is very specific and results in a striated appearance when viewed with the microscope. This type of muscle tissue is found mainly in the skeletal muscles.
- Cardiac Muscle Tissue. The cells (muscle fibers) of cardiac muscle tissue are short, branched, contain one nucleus, and are striated. This tissue makes up the myocardium (wall) of the
- Smooth Muscle Tissue. The cells (muscle fibers) of smooth muscle tissue are spindle-shaped, contain one nucleus, and are not Smooth muscle tissue is generally found in the walls of hollow organs such as the organs of the digestive and respiratory systems, the blood vessels, the ureters, urinary bladder, urethra, and reproductive ducts.
DEFINITION OF NERVOUS TISSUE
Nervous tissue is a collection of cells that respond to stimuli and transmit information.
INTEGUMENTARY AND FASCIAL
SYSTEMS
Basic Human Anatomy Lesson 3: The Human Integumentary and Fascial Systems Welcome to Lesson 3 of the Basic Human Anatomy Course. Today, we’ll be studying the Human Integumentary and Fascial Systems. I have 5 goals for you in this lesson:
- Be able to Define the terms a. integumentary system b. integument proper
