Module 1 - Foundations of the Human Anatomy PDF

# Module 1- Foundations of the Human Anatomy ## Section 1- The Importance of Anatomy - **Anatomy:** the study of structure - In anatomy, the structure of an organism are "cut apart" in order to ascertain their positions, relations, structure, and function. ### Four Areas of Anatomy: 1. **Histolo...

# Module 1- Foundations of the Human Anatomy ## Section 1- The Importance of Anatomy - **Anatomy:** the study of structure - In anatomy, the structure of an organism are "cut apart" in order to ascertain their positions, relations, structure, and function. ### Four Areas of Anatomy: 1. **Histology:** (microscopic features) 2. **Gross anatomy:** (macroscopic features) 3. **Neuroanatomy** 4. **Embryology** **Course focuses on these** ## Unity of Form and Function - The organization of a bodily structure is instrumental as it is the means by which a specific function is carried out. - When form is disturbed, dysfunction may occur. ## Section 02- Organization of the Human Body and Anatomical Nomenclature ### Organization of the Human Body 1. **Chemical Level:** A molecule is a group of atoms bonded together. 2. **Cellular Level:** Cells are the smallest living structure and are formed from atoms and molecules. 3. **Tissue Level:** Tissues are similar cells that perform specialized functions. 4. **Organ Level:** Organs are two or more tissues that work together to perform complex functions. 5. **Organ System Level:** The organ system level consists of related organs that work together to coordinate activities and achieve a common function. 6. **Organismal Level:** All body systems function interdependently in a single living human. The body can also be organized into two main regions: 1. **Axial:** These regions form the main vertical axis of the body, and includes the head, neck, and trunk. 2. **Appendicular:** Includes the limbs or appendages that attach to the axis. ### Organ Systems: 1. **Integumentary:** Makes up our body covering, includes our skin and associated structures such as our hair and nails. 2. **Skeletal:** Includes the bones and joints of the body. 3. **Muscular:** Contains the muscles that work together to provide movement and support. 4. **Nervous:** Includes the brain, spinal cord, and nerves that run through the body. 5. **Endocrine:** Includes glands that produce and secrete hormones. 6. **Digestive:** Starts at the mouth with a long tube and ends at the anus. 7. **Respiratory:** Allows you to breathe and includes the nose, air passageways, and lungs. 8. **Cardiovascular:** Includes blood, blood vessels, and the heart. 9. **Lymphatic:** Includes the lymphatic vessels, cells, and structures that can initiate an immune response. 10. **Urinary:** Includes kidneys, ureters, bladder, and urethra. 11. **Reproductive:** Provides the means for the sexual maturation and procreation of each individual. ### Body Cavities: - The areas protected within membranes that contain and seperate our organs. 1. **Dorsal Body Cavity (at the back):** - Contains the *cranial body cavity* that houses the brain and the *vertebral body cavity* which contains the spinal cord. 2. **Ventral Body Cavity (at the front):** - Contains the *thoracic cavity* which contains everything above the diaphragm and the *abdominal-pelvic cavity* which is everything below the diaphragm. - **The thoracic cavity can be further divided into the superior mediastinum containing the esophagus and trachea (which are protected by the sternum), the pericardial cavity containing the heart, and the left and right pleural cavities containing the lungs.** - The abdominal-pelvic cavity can also be further divided into the abdominal cavity consisting digestive viscera and the pelvic cavity containing the urinary bladder and reproductive organs. ## Characteristics of Proper Anatomical Position: 1. Standing upright. 2. Feet parallel on the floor. 3. Head level and looking forward. 4. Arms at side of body. 5. Palms facing forward and thumbs pointing away from the body. ## Directional Terms: - **Superior:** Above. - **Anterior:** Front. - **Medial:** Towards the middle. - **Proximal:** Near origin location of limb attachment. - **Superficial:** Close to body's surface. - **Parietal:** Indicating component of the body walls (may include muscles, connective tissue, and tissue covering the organs). - **Inferior:** Below. - **Posterior:** Behind. - **Lateral:** Towards the sides. - **Distal:** Away from origin. - **Deep:** Far from body's surface. - **Visceral:** Lines the outer surfaces of organs that are located within cavities. ## Planes and Sections of the Body: - **Sagittal:** A vertical plane that divides the body into left and right parts. - When it passes specifically through the midline it is called the **midsagittal plane**. - **Coronal/Frontal:** A vertical plane that divides the body into anterior and posterior parts. - **Horizontal/Transverse:** Divides body into superior and inferior parts. - **Oblique:** A plane that passes through the body at an angle. - **Longitudinal:** Any plane perpendicular to the horizontal plane (ie. Sagittal and coronal). ## Section 03- Basic Tissue (Epithelium) ### Four Types of Basic Tissue: 1. Epithelial tissue 2. Connective tissue 3. Nervous tissue 4. Muscular tissue ### Epithelium: - A tissue composed of closely apposed (side by side) cells with very little to no intervening intercellular substance. - There are two types: 1. **Covering epithelium:** Cells that cover the external and internal surfaces. 2. **Glandular epithelium:** Cells that produce and secrete product (such as hormones). ### Characteristics of Epithelium: 1. **Cellularity:** Adjacent epithelial cells are joined by specialized junctions. 2. **Polarity:** Epithelial cells have an exposed (apical) surface that faces the exterior of the body or internal space, and a *basal surface* where it is attached to the underlying tissue. 3. **Attachment:** Epithelial cells rest on and are attached to the *basal lamina* (basement membrane) by junctional complexes. They have no direct blood supply, they receive nutrients from the blood vessels in the underlying tissue. 4. **Regeneration:** They are renewed continuously. ### Functions of Epithelium: 1. **Support + Protection:** It covers and lines external and internal surfaces of the body protecting the underlying tissue from injury, pathogens, and dehydration. 2. **Permeability:** Allows substances to be absorbed into the body. 3. **Sensation:** Some epithelial tissue contain specialized cells that are able to detect sensory stimuli. 4. **Secretion:** Some epithelial cells are specialized to secrete substances. ### Classification of Epithilium: 1. **Cell Organization (number of cell layers)** - **Simple:** One cell layer thick - **Stratified:** Two or more cell layers thick - Only the deepest layer is in contact with the basal lamina. 2. **Cell Shape** - **Squamous:** Flat/thin, wide, and somewhat irregular in shape. - **Cuboidal:** About the same size on all sides with the nucleus typically located in the center of the cell. - **Columnar:** Taller than they are wide, nucleus is oval and located in the basal region. Epithelial tissues are named by combining their two classifications: - Cell organization (1st) + cell shape (2nd) ### Simple Epithelium - **Simple squamous:** Consists of a single layer of flattened cells. - Can be found lining blood vessels. - Allow for exchange of materials. - **Simple Cuboidal:** Consists of a single layer of cube cells. - Can be found lining some glands. - **Simple Columnar:** Consists of a single layer of column shaped cells. - Can be found lining the GI tract. - Also allows for rapid secretion + absorption. ### Stratified Epithelium - **Stratified Squamous:** Multiple layers of flat shaped cells. - Basal cells may be more cuboidal in shape. - Makes up the most superficial layer of skin. - Allows the skin to protect the deeper structures. - **Stratified Cuboidal:** Multiple layers of cube shaped cells. - Can be located in some ducts of glands. - Functions include; secretion, protection, and strengthening the walls of ducts of glands. - **Stratified Columnar:** Multiple layers of column shaped cells. - Relatively rare in the human body. - Can be found in the male urethra. - Functions include protection and secretion. ### Other Types of Epithelium: - **Transitional:** Consists of multiple layers of epithelial cells that allows for stretching. - Vary in shape depending on whether the tissue is stretched or relaxed. - These tissues have rounded shaped surface cells when relaxed. - They flatten out when stretched. - In the bladder they change shape as urine accumulates. - **Pseudostratified Ciliated Columnar):** Comprises only a single layer of cells and has its cell nuclei positioned in a manner suggestive of stratified epithelium. - Short cilia on the surface of these cells help in moving mucous. - Found throughout most of the respiratory tract. ## Section 04-Connective Tissue - The most widespread and abundant tissue in the human body, it is also the most diverse in the four types with a wide variety of functions. - Ranges in consistency, from gel-like softness to the hardness of bone. ### Functions of Connective Tissue (Examples): 1. **Support + Protection:** The bones of the skull protect the brain and the kidneys are surrounded by a fat padding that protects it. 2. **Structural Framework for the Body:** Cartilage support body structures such as the trachea/windpipe, ear, and nose. Bones of the skeleton provide the framework for skeletal muscles. 3. **Medium for Exchange:** Blood serves as a medium that carries gases, nutrients, waste, and blood cells to different parts of the body. 4. **Storage + Repair:** Bones store minerals such as calcium, fat serves as a major energy resevoir for the body. 5. **Defense:** Acts as a physical barrier and though wbc + antibody production. ### Components of Connective Tissues: 1. **Cells:** Some CTs have a large diversity of cell types and others the diversity is low. Some cells are fixed (permenant residents in the CT) and others are wandering (transient migrants who have entered the CT from the blood in response to specific stimuli). 2. **Fibres:** Formed by proteins made of long peptide chains, different components and proportions of fibre types lead to diverse functions of various CT types. - **There are 3 types:** - **Collagen Fibres:** Provide tensile strength, the most common fibre type, flexible fibres with high tensile strength, microscopic structure appears similar to rope. - **Elastic Fibres:** Thin and branched, appear wavy/curly, and they have a rubber-like material that is able to stretch. - **Reticular Fibres:** Thin fibres that form a branching interwoven network with no common alignment. 3. **Ground Substance:** Occupies the space between the cells and fibres of connective tissue, has a high water content, is transparent, colourless, and viscous. ### Types of Connective Tissue: **Connective Tissue Proper** 1. **Loose CT:** Has more ground substance with few CT fibres. - Ex: Adipose tissue - a specialized type of loose CT where fat cells account for most of the volume, acts as padding, insulates, and packing/Filler between and Around structures. 2. **Dense CT:** Has less ground substance and more CT fibres. - Ex: Elastic tissue - composed of bundles of thick parallel elastic fibres. Collagen and fibroplasts are found between which some fibres are found, has the ability to stretch and recoil. **Supporting Connective Tissue** 1. **Bone:** Important structural tissue that forms the framework of the body. 2. **Cartilage:** **Specialized (Fluid) Connective Tissue** 1. **Blood:** The fluid within blood vessels and the heart, contains various cells + proteins and performs a number of essential functions within the body. 2. **Lymph:** An interstitial fluid (bathes cells) that is collected into thin-walled lymphatic vessels and transported to the cardiovascular system. ## Histology: - Identifying the microscopic features of tissue. - Helps us classify tissues and identify particular structures we find in one tissue vs another. ### Cartilage: - An important structural component, a firm tissue but is softer and much more flexible than bone. - Found in many areas of the body: - Joints between Moveable bones. - Between the vertebrae in the spine. - Ears and nose. - Bronchial tubes or areas. ### Components of Cartilage: 1. **Cells:** They are primarily chondrocytes, which are located throughout the ground substance in small spaces called lacunae that contain one or more cells. 2. **Fibres:** Include various collagen and elastic fibres scattered throughout. 3. **Ground Substance:** Like a firm gel that makes cartilage solid. - It is avascular so it cannot get them on its own. 4. **Perichondrium:** Dense, irregular CT that envelopes cartilage to provide it nutrients, not all types of cartilage have a perichondrium. ### Types of Cartilage: 1. **Hyaline:** - Wear-resistant tissue designed to bear and distribute weight. - Strong, rubbery, and flexible. - Found on joint surfaces of moveable joints, walls of the nose, trachea, bronchi, and ribs. 2. **Fibrocartilage:** - Tough and inflexible. - Durable and resistant to compression. - Found in intervertebral discs and symphysis pubis 3. **Elastic:** - More flexible than hyaline. - Found in the external ear, Eustachian tube, and epiglottis. ## Bone - Another important structural component of the body. ### Functions of Bone: 1. Support 2. Blood cell production 3. Locomotion 4. Mineral metabolism 5. Protection ### Composition of Bone: 1. **Organic components (1/3):** Cells, fibres, and ground substance. 2. **Inorganic components (2/3):** Minerals and salts. - These are what makes bones rigid. ### Osteons: - The structural unit of bone. - Cylindrical structures, made of concentric rings with a hollow central canal also known as a Haversian canal. - Cellular components of bone are located between concentric rings.