Types of Tissues (COOKED 4) - PDF

**4.1 Types of Tissues (COOKED 4)** - Connective tissue- binds and supports body parts - Muscular tissue- moves the body and its parts - Nervous tissue-conducts nerve impulses - Epithelial tissue- covers body surfaces; lines body cavities **4.2 Connective Tissue Connects and Support...

**4.1 Types of Tissues (COOKED 4)** - Connective tissue- binds and supports body parts - Muscular tissue- moves the body and its parts - Nervous tissue-conducts nerve impulses - Epithelial tissue- covers body surfaces; lines body cavities **4.2 Connective Tissue Connects and Supports** ***Connective Tissue Components*** - Specialized cells, ground substances, and protein fibers - Ground substance- noncellular material between the cells - Varies in consistency from solid (bone) to fluid (blood) Three types of protein fibers - Collagen fibers- flexible and strong - Reticular fibers- thin, highly branched collagen fibers - Elastic fibers- contain elastin, a protein that stretches and recoils **Fibrous Connective Tissue** - Comes in two main forms: loose and dense - Both contain fibroblasts separated by matrix (ground substance and fibers ***Loose fibrous connective tissue*** - includes areolar connective tissue, reticular connective tissue, and adipose tissue (supports epithelium and many internal organs) ***Dense fibrous connective tissue*** - found in tendons (connect muscles to bones) and ligaments (connect bones to bones) - Contains densely packed collagen fibers ***Adipose tissue (loose)*** - Very little extracellular matrix - Adipocytes- cells filled with liquid fat - Function in energy storage, insulation, and cushioning - Found primarily under the skin and around some organs **Supportive Connective Tissue** - Two major types- cartilage and bone - Functions in structure, shape, protection, and leverage for movement - Cartilage is more flexible than bone because it lacks mineralization of the matrix **Cartilage** - Chondrocytes and chondroblasts- cells that lie in small chambers called lacunae - Matrix is solid but flexible - Lacks a direct blood supply, so heals slowly Three types, distinguished by the type of fiber found in the matrix - Hyaline cartilage- fine collagen fibers (found in the tip of the nose, ends of long bones and the fetal skeleton) - Elastic cartilage- lots of elastic fibers. (found in the outer ear) - Fibrocartilage- strong collagen fibers. (Found in the disks between vertebrae) **Bone** The most rigid connective tissue - Matrix is made of collage and calcium salts - Salts surround protein fibers, which provide elasticity and strength (steel rods in reinforced concrete) - Compact and spongy are types of bone tissue. - Cells called osteoblasts and osteoclasts form the matrix in bone tissue Compact bones make up the shafts of long bones. - Consists of cylindrical structural units called osteons - The central canal contains blood vessels and nerves - Bone cells are in lacunae Spongy bone is inside the end of long bones - Lighter than compact bone, but strong **Fluid Connective Tissue 1** - Two types of fluid connect tissue: blood and lymph ***Blood and lymph*** Cooked 6 covers this Though lymph contains wbcs **4.3 Muscular Tissue Moves the Body** **Muscular Tissue** - Specialized to contract - Cells are called muscle fibers - Skeletal, smooth, and cardiac **Skeletal Muscle** - Attached to the skeleton by tendonds - Contraction moves the skeleton - Voluntarily controlled - Muscle fibers are very long; can run the entire length of the muscle - Have multiple nuclei - Straited, or striped, in appearance **Smooth Muscle** - No striations - Spindle-shaped cells with one nucleus - Involuntarily controlled - Found in the walls of viscera **Cardiac Muscle** - Found only in the walls of the heart - Striated - Involuntarily controlled - Single nucleus - Cells are connected by intercalated disks **4.4 Nervous Tissue Communicates** **Nervous Tissue** - Consists of neurons and neuroglia - Sensory input, integration, and motor output. **Neurons** - Dendrites, a cell body, and an axon - Dendrites carry the information toward the cell body - The cell body contains the nucleus and other organelles - Axon conducts nerve impulses away from the cell body - Some axons are covered in myelin, a fatty substance Nerves- bundles of axons traveling to and from the brain and spinal cord **Neuroglia** - Outnumber neurons 9 to 1 - Take up more than half the volume of the brain - Main function is to support and nourish neurons **4.5 Epithelial Tissue Protects** - Made of tightly packed cells - Lines body cavities, covers body surfaces, and is found in glands - Anchored by a basement membrane on one side and is free on the other side - Named for the number of cell layers and the shape of the cells - Simple vs stratified; squamous, columnar, or cuboidal **Simple epithelia** ***Simple squamous epithelium*** - Single layer of flattened cells - That is, found in the lungs, where it functions in gas exchange ***Simple cuboidal epithelium*** - Single layer of cube-shaped cells ***Simple columnar epithelium*** - Single layer of column-shaped cells ***Pseudostratified columnar epithelium*** - Because of the location of the nuclei, it appears stratified but every cell touches the basement membrane - Often has cilia, which moves mucus across its surface ***Gland*** - One or more cells that make and secrete a product - Two types: exocrine and endocrine - Exocrine glands secrete into ducts - Endocrine glands secrete into blood stream; have no ducts **Stratified Epithelia** - Several layers of cells ***Stratified Squamous epithelia*** - Forms the outer layer of the skin and lines the mouth, esophagus ***Transitional epithelia*** - Cells change shape in response to tension (cuboidal to squamous) - Found lining in the urinary bladder **4.6 Organ Systems, Body Cavities, and Body Membranes** Organs and cavities are lined with membranes, many of which secrete fluid **Anatomical Terms** - Ventral or anterior refers to the front - Dorsal or posterior means toward the back - Superior means toward the head - Inferior means toward the feet Some are relative to other body parts - Something that is medial is closer to the midline of the body - Lateral, away from the midline When referring to an appendage like an arm or a leg - Proximal means closer to the trunk of the body - Distal means away from the trunk **Organ Systems** - Some organs are involved in the function of more than one organ system - For example, the pancreas plays a role in the endocrine and digestive systems - Other structures and glands also contribute to the operation of organ systems **Body Cavities** - Two main cavities: dorsal and ventral ***Ventral cavity (coelom in early development)*** - Contains the thoracic, abdominal, and pelvic cavities - The diaphragm separates the thoracic and abdominal cavities - The thoracic cavity contains the lungs and the heart - The abdominal cavity contains the stomach, liver, spleen, pancreas, gallbladder, and most of the small and large intestines - The pelvic cavity contains the rectum, the urinary bladder, the internal reproductive organs, and the rest of the small and large intestines - Males have an external extension of the abdominal wall called the scrotum, which contains the testes ***Dorsal cavity*** - Contains the cranial cavity and vertebral canal **Body Membranes** - Line cavities and the internal spaces of organs and tubes that open to the outside - Four types: mucous, serous, and synovial membranes and the meninges ***Mucous membranes*** - Line the tubes of the digestive, respiratory, urinary, and reproductive systems - Composed of epithelium overlying loose fibrous connective tissue - Contains goblet cells that secrete mucus ***Serous membranes*** - Line closed cavities (not open to the environment) and cover the surface of the organs contained within - That is, pleurae line the thoracic cavity and cover the lungs - That is, pericardium forms the pericardial sac and covers the heart - That is, double layer of peritoneum, called mesentery, lines the abdominal cavity and covers its organs ***Synovial Membranes*** - Composed only of loose connective tissue - Line freely moveable joints - Secrete synovial fluid for lubrication ***Meninges*** - Composed only of connective tissue - In the dorsal cavity (protects the brain and spinal cord) - Meningitis- inflammation of the meninges **4.7 Integumentary System** - Includes skin and accessory organs such as hair, nails, and glands Functions: - Protects underlying tissue from trauma, pathogen invasion, and water loss - Helps regulate body temp - Contains sensory receptors, such as touch and temp receptors - Makes us aware of our surroundings Contains all 4 tissue types - Skin has two main regions: the epidermis and the dermis - Under the skin there is a subcutaneous layer (hypodermis) - The subcutaneous layer is between the skin and underlying structures, such as muscle or bone **Epidermis** - Thin, outermost layer of the skin - Stratified squamous epithelium - Stem cells that produce new epidermal cells are in the deepest layer - If an injury destroys the stem cells, skin needs to be replaced - Autograft- from another area of the body - Allograft- from another person ***Cells of the Epidermis*** Keratinocytes- in the upper layers of epidermis - Dead and filled with keratin - Forms a waterproof barrier Langerhans cells - A type of white blood cell Melanocytes - Product melanin - Produces skin color and protects from UV light - People have the same number of melanocytes, but the amount of melanin produced varies Other contributors to skin color: carotene and hemoglobin - Epidermal cells produce vitamin D when exposed to UV rays - Vitamin D is important in the regulation of calcium and phosphorus levels in the body **Skin cancer** - Caused by ultraviolet rays from the sun ***Basal cell carcinoma*** - Cancer of epidermal stem cells - Most common type of skin cancer; easily curable ***Melanoma*** - Cancer of melanocytes - Extremely serious **The Dermis** - Thick, inner layer of the skin - Made of dense fibrous connective tissue - Contains collagen and elastic fibers for strength and elasticity - Contains blood vessels, sensory receptors, and glands - Sensory receptors are specialized for touch, pressure, pain, heat, and cold **The Subcutaneous Layer** - Technically not part of the skin - Composed of loose connective tissue and adipose tissue - Stores energy, insulates, and protects **Accessory Organs of the Skin** ***Nails*** - Nails offer a protective covering of the digits (fingers and toes) - Nails grow from the nail root to cover the nail bed - The cuticle covers the nail root - Lunula- white half moon shape at the base ***Hair*** - Hair follicles- epidermal structures that surround the hair itself - Hair shaft- the portion of hair protruding from the skin - The color of hair comes from melanin; as melanocytes age, they produce less pigment and hair turns gray - Arrector pili muscles- attached to the hair follicle - Can contract, which creates goosebumps ***Oil Glands (sebaceous glands)*** - Produce sebum, which softens the hair and skin - Also retards bacterial growth - Acne-inflammation of the sebaceous glands ***Sweat glands (sudoriferous glands)*** - In the dermis, their ducts open onto the skin surface - Help to regulate body temperature **4.8 Homeostasis** - Relatively constant internal environment - Blood glucose, ph, body temp - If conditions vary too much, illness results **The Internal Environment** - Blood and interstitial fluid - Blood delivers oxygen and nutrients to the tissues and carries away co2 and waste - Interstitial fluid surrounds body cells: substances are exchanged through it - Body systems work together to keep these substances within the range or normalcy **Body Systems and Homeostasis** The nervous and endocrine systems coordinate the other organ systems - The nervous system is faster, but the effects of the endocrine system last longer - The Endocrine system secretes hormones-chemical messengers that travel in blood **Negative Feedback** - The primary mechanism used in the body - Two components: a sensor and control center - The output of the system turns down, or off, the production - That is, how a furnace works - Temperature regulation **Positive Feedback** - Brings about a change in the same direction as the original stimulus - Childbirth: the fetus's head pushes against the cervix, which stimulates signals that are sent to the brain - The brain then secretes the hormone oxytocin, which causes stronger contractions - This causes more oxytocin to be released - Childbirth stops the positive feedback - Can be harmful in some situations (fever)