Transcript Lecture 4
Glandular Epithelium • Main Function: Secretion • Location: Lie in clusters deep to the covering and lining epithelium Two Types • Endocrine • Exocrine Endocrine • Secrete hormones into the bloodstream Endocrine • Location: pituitary, thyroid, and adrenal glands Exocrine • Secrete products that are released onto the skin surface or into the lumen of a hollow organ. Exocrine • Products secreted: mucus, sweat, oil, earwax, saliva, and digestive enzymes. Exocrine • Most glands are multicellular, but some are single-celled like goblet cells. Exocrine Glands • Merocrine secretion - their products are synthesized on fixed ribosomes (RER), package in the golgi apparatus in secretory vesicles and released via exocytosis. Exocrine Glands Continued • Holocrine secretion - a secretory product accumulates in the cytosol. Once the cell matures it bursts and the cell itself becomes the secretory product. • Example: Sebaceous glands Connective Tissue • Vascular except cartilage and tendons Connective Tissue • Has a nerve supply Connective Tissue • Two major components: 1. Cells 2. Matrix Types of Cells 1. Mesenchymal Cells: Mesodermal embryonic cells that give rise to cells of the connective tissue. Types of Cells 2. Fibroblasts: Immature cells that secrete the matrix in loose and dense connective tissue. Types of Cells 3. Chondroblasts: cells that secrete the matrix in cartilage. Types of Cells • Once the matrix is produced, chondroblasts differentiate into mature cells called chondrocytes. Types of Cells 4. Osteoblasts: Immature cells that secrete the matrix in bone. Types of cells • Once the matrix is produced, osteoblasts differentiate into mature cells called osteocytes. Types of Cells 5. Macrophages: Engulf bacteria and cellular debris by phagocytosis. Types of Cells Found in lungs and spleen Types of Cells 6. Plasma Cells: They secret antibodies. (Antibodies are proteins that attack foreign substances) Types of Cells Found in salivary glands, lymph nodes, red bone marrow, GI tract, and respiratory tract. Types of Cells 7. Mast Cells: Produce histamine. (Histamine dilates small blood vessels when the body undergoes injury or infection) Types of Cells Found in blood vessels Type of Cells 8. Adipocytes: Are fat cells that store triglycerides. Type of Cells Found below skin, around the heart and kidney. Types of Cells 9. White Blood Cells: Not normally found in connective tissue. They Migrate from the blood into connective tissue in cases of infection, parasitic invasion, and allergic responses. Connective Tissue Matrix • Consists of: 1. Ground Substance 2. Fibers Ground Substance • Between cells and fibers Ground Substance • Supports cells and binds them together Ground Substance • Composed of interstitial fluid, cell adhesion proteins, and proteoglycans. Fibers 1. Collagen 2. Elastic 3. Reticular Collagen Strong and resist pulling forces Collagen Occur in bundles parallel to each other Collagen Found in bone, cartilage, tendons, and ligaments Elastic Strong and can be stretched up to 150% of their relaxed length. Elastic Contain the property elasticity. Elastic Found in skin, blood vessel walls, and lung tissue Reticular Fibers Provide support and strength Reticular Fibers • Thinner than collagen fibers and form branching networks Reticular Fibers Form a network around cells in areolar, adipose, and smooth muscle tissue. Reticular Fibers Found in spleen and lymph nodes. Types of Connective Tissue • Mesenchyme • Mucous connective tissue • Areolar connective tissue • Adipose connective tissue • Reticular connective tissue • Dense regular connective tissue • Dense irregular connective tissue Types continued • Elastic Connective Tissue • Hyaline Cartilage • Fibrocartilage • Elastic Cartilage • Bone tissue • Blood tissue • Lymph Mesenchyme • Irregular shaped mesenchymal cells Mesenchyme • Ground substance contains reticular fibers Mesenchyme • Mostly found under skin and along bones of embryo Mesenchyme • Function: Forms all other connective tissue Mucous Connective Tissue • There are widely scattered fibroblasts. Mucous Connective Tissue • Contains collagen fibers in ground substance. Mucous Connective Tissue • Found in umbilical cord of fetus Mucous Connective Tissue • Support Areolar Connective Tissue • Loose Connective Tissue Areolar Connective Tissue • Contains collagen, elastic, and reticular fibers Areolar Connective Tissue • Contains fibroblasts, macrophages, plasma cells, adipocytes, and mast cells Areolar Connective Tissue • Found in subcutaneous layer of the skin, papillary region of dermis of skin, and around nerves, blood vessels, and organs Areolar Connective Tissue • Function: Attaches skin to underlying tissues and organs, strength, elasticity, and support. Adipose Tissue • Loose Connective Tissue Adipose Tissue • Contains adipocytes (store triglycerides) Adipose Tissue • The nucleus and cytoplasm of these cells are in the periphery Adipose Tissue • Found in the subcutaneous layer deep to the skin, around the kidney and heart, yellow bone marrow. Adipose Tissue • Function: Reduces heat loss, supports, protects, and serves as an energy reserve Reticular Connective Tissue • Loose Connective Tissue Reticular Connective Tissue • Contains reticular fibers and reticular cells Reticular Connective Tissue • Found in liver, spleen, lymph nodes, red bone marrow, blood vessels, and muscles Reticular Connective Tissue • Function: Forms the supporting framework of organs, binds smooth muscle tissues together, filters and removes worn-out blood cells in the spleen and microbes in lymph nodes Dense Regular Connective Tissue • Dense Connective Tissue Dense Regular Connective Tissue • Contains collagen fibers arranged in parallel bundles Dense Regular Connective Tissue • Shiny white matrix Dense Regular Connective Tissue • Contains fibroblasts in rows in between parallel bundles Dense Regular Connective Tissue • Found in tendons and ligaments Dense Regular Connective Tissue • Function: Provides attachment between structures Dense Irregular Connective Tissue • Dense Connective Tissue Dense Irregular Connective Tissue • Contains irregularly arranged collagen fibers Dense Irregular Connective Tissue • Few Fibroblasts Dense Irregular Connective Tissue • Found in reticular region of the dermis of skin, periosteum, perichondrium, joint capsules, pericardium, heart valves, and in membrane capsules of kidneys, livers, testes, and lymph nodes Dense Irregular Connective Tissue • Function: strength Elastic Connective Tissue • Dense Connective Tissue Elastic Connective Tissue • Contains elastic fibers Elastic Connective Tissue • Contains fibroblasts in between fibers Elastic Connective Tissue • Found in lung tissue, walls of elastic arteries, trachea, bronchial tubes, and true vocal cords Elastic Connective Tissue • Function: Enables organs to stretch Hyaline Cartilage • Cartilage Hyaline Cartilage • Collagen fibers Hyaline Cartilage • Abundant chondrocytes Hyaline Cartilage • Bluish white shiny ground substance Hyaline Cartilage • Found in ends of long bones, ends of ribs, nose, parts of larynx, trachea, bronchi, and embryonic and fetal skeleton Hyaline Cartilage • Function: Gives a smooth surface for movement in joints, flexibility, and support Fibrocartilage • Cartilage Fibrocartilage • Collagen Fibers Fibrocartilage • Chondrocytes Fibrocartilage • Pubic symphysis, intervertebral discs, menisci of knee, and parts of tendons that insert into cartilage Fibrocartilage • Function: Support and fusion Elastic Cartilage • Cartilage Elastic Cartilage • Elastic Fibers Elastic Cartilage • Chondrocytes Elastic Cartilage • Located in epiglottis, external ear, and auditory tubes Elastic Cartilage • Function: Support and maintains shape Compact Bone • Bone Compact Bone • Contains osteons Compact Bone • Osteocytes Compact Bone • Found in bones of the body Compact Bone • Function: Support, protection, storage, movement Blood • Blood Blood • Blood plasma Blood • Red blood cellls, white blood cells, and platelets Blood • Found in Blood vessels and chambers of heart Blood • Function: RBC’s transport oxygen and carbon dioxide, WBC’s involved in immune system response and allergic reactions, platelets involved in clotting Muscle Tissue • Skeletal • Cardiac • Smooth Skeletal • Striated Skeletal • One nucleus Skeletal • Voluntary control Skeletal • Nucleus located in periphery Skeletal • Found attached to bone by tendons Skeletal • Function: Motion, posture, and heat production Cardiac • Striated Cardiac • Usually contains one nucleus, but some times contains two Cardiac • Involuntary Control Cardiac • Nucleus located in center Cardiac • Fibers Branched Cardiac • Found in Heart wall Cardiac • Pumps blood everywhere Smooth • Nonstriated Smooth • One nucleus Smooth • Involuntary Smooth • Nucleus located in center Smooth • Spindle shaped fibers Smooth • Found in walls of blood vessels, airways to lungs, stomach, intestines, gallbladder, urinary bladder, and uterus Smooth • Function: Motion Nervous Tissue • Neurons: nerve cells • Neurons contain: Cell body Dendrites Axons Nervous • Found in nervous system Nervous • Function: Converts stimuli to nerve impulses, and conducts these nerve impulses to other neurons, muscle fibers, and glands Membranes • Made up of epithelial and connective tissue Membranes • 1. 2. 3. 4. 4 types: Mucous Serous Cutaneous synovial Mucous • Lines the passages of the digestive, respiratory, urinary, and reproductive tracts Mucous • Made up of epithelium with areolar connective tissue beneath Serous • Lines cavities that are not open to the exterior (peritoneal, pleura, and pericardial) Serous • Made up of transudate(fluid that reduces friction), mesothelium, and areolar connective tissue Cutaneous • Skin Cutaneous • Made up of stratified squamous epithelium, areolar connective tissue, and dense irregular connective tissue Synovial • Lines joint cavities Synovial • It consists of epithelium with overlying areolar connective tissue