TISSUES AND ORGANS:
EPITHELIUM:
https://histology.medicine.umich.edu/full-slide-list
Lecture Objectives: Chapter 4 Tissues, Chapter 6 Skin and Membranes:Upon completion of these lectures and chapters, you should be able to:
- Define "extracellular matrix" and state the components of the matrix.
- Discuss how the components of the extracellular matrix may affect the function of a tissue.
- Explain how epithelial tissue is categorized by shape and arrangement of cells.
- List and discuss the major types of connective tissue and the components of each.
- Compare and contrast the three major types of muscle tissue, including their structure, function, and where they are found throughout the human body.
- Describe the structure and function of the nervous tissue.
- List the three structural components of a neuron.
- State the four primary tissue types.
- Identify the four primary tissue types and state their functions.
- Compare and contrast primary tissue structure and function.
- Identify examples of epithelial, connective, muscular, nervous tissue types, and describe their location and function.
- Describe the layers of the epithelium, dermis, and subcutaneous layers and the accessory organs found in the dermis.
- Differentiate the different types of epithelial tissue, including simple, complex, squamous, cuboidal, columnar, stratified, pseudostratified, and ciliated and identify examples of each and where they are located in the body.
- Explain the function of the integumentary system.
- Identify the first, second, third and fourth degree burns.
- Utilize the ABCDE method to identify skin conditions and changes in them that may indicate different types of skin cancers.
- Differentiate the 3 major types of skin cancers and state the most deadly type and how to identify it.
Objectives: Integumentary System
- Describe the structure and Function of the Integumentary System
- Identify the epidermis, dermis, and hypodermis
- Describe the structure and function of the epidermis and accessory structures
- Identify the accessory structures of the skin
Lab: Microscopy Observation of 4 Tissue Types: Muscle, Epithelial, Connective, Nervous Tissue Slides
Tissues are integrated groups of similar cells that perform a specific function, such as secretion, heartbeat, and many others. Two or more tissue types fuse together to form organs. Humans are multicellular organisms whose tissues work together to perform common functions. There are 4 primary types of tissue:
Tissues are then organized into organs like the heart, brain, lungs, liver and kidneys and many more. The skin is actually the largest organ of the body! Take care of your skin because it is hard to replace!
- Epithelial Tissue
- Covers surfaces
- Lines surfaces
- Structure Includes:
- Skin
- Hair
- Glands
- Nails
- Skin
- Functions Include:
- Protection/Barrier/First line of defense
- Absorption
- Secretion
- Excretion
- Filtration
- Sensory reception
- Cells with different shapes, which are close together and held together via several different types of junctions
- Attached, supported and held in place by a basement membrane
- Rely on tissues underneath for blood supply
- Types of Layers:
- Simple
- Stratified
- Pseudostratified
- Transitional
- Cellular Shapes:
- Squamous
- Cuboidal
- Columnar
- Connective Tissue
- Muscular Tissue
- Nervous Tissue
Tissues are then organized into organs like the heart, brain, lungs, liver and kidneys and many more. The skin is actually the largest organ of the body! Take care of your skin because it is hard to replace!
Epithelium: Layers and Cellular Shapes
A. Simple Squamous: simple, single layer, flattened cells with one single central nucleus, not much cytoplasm
- Examples: cheek cells, alveoli of lungs, glomeruli of kidneys, lining of blood vessels, lining of the heart, lining of the serous membranes (body cavities)
- Enables materials to pass through via diffusion for respiration, formation and filtration of urine, absorption of minerals and excretion of wastes, lubrication of membranes for movement and to prevent friction or collapse
- Examples: lining of the kidney tubules, ducts of small glands, surface of the ovaries
- Enables secretion of fluids, oils, waxes, hormones and enables absorption
- Examples: goblet cells that secrete mucus, ciliated cells of the respiratory tract, microvilli cells covering the intestines, non-ciliated type lining the digestive tract and gallbladder, ciliated cells of the fallopian tubes
- Enable absorption, secretion of mucus, enzymes, other substances; movement ("sweeping" motion); microvilli increase surface area for absorption
- Examples: goblet cells, some ciliated cells, some nonciliated, line ducts of large glands, ciliated type line the trachea and most of the upper respiratory tract, line parts of the male urethra
- Enable secretions of mucus and movement due to the "sweeping" of the cilia
- Examples include the keratinized surface cells full of keratin which are dead, basal cells active in mitosis, cells that make and store the pigment melanin, cells of the superficial layers, cells that form the membranes that line the moist areas of the body
- Enable protection of underlying tissues
- Examples include cells that line the ureers and bladder
- Enable stretching of cells to hold urine and allow distension of the urinary organs for urine storage
ENDOTHELIUM:
Endothelium: "Endo" means "inside", so this tissue lines organs, glands, blood vessels and other structures inside the body. The images below are examples of endothelium lining blood vessels in the body.
SKIN: Part of the Integumentary System
Basement Membrane:
CONNECTIVE TISSUES:
Connective tissue is the most abundant of the 4 tissue types. Connective tissues contain cells that are found throughout the extracellular matrix. The matrix is basically protein fibers embedded in a matrix, which may be either liquid, gel-like or solid. Connective tissue serves as an anchor that protects, supports and holds (binds or "glues") other tissues and organs in place. Connective tissues are found in all parts of the body and include the following:
1) Bone (Osseous Tissue)
1) Bone (Osseous Tissue)
- Cells suspended in an extracellular matrix hardened by minerals, including calcium, magnesium and phosphorus
- Blood vessels run through bones for growth and healing and repair
- Hard, calcified matrix
- Collagen fibers
- Osteocytes in lacunae
- Contains red blood cells, white blood cells and platelets
- Functions in immunity, transport, temperature maintenance and blood clotting
- Cells are suspended in a liquid called plasma
- Cells are suspended in a strong and flexible matrix (extracellular matrix)
- Forms the padding at the ends of bones and between the vertebrae (shock absorption)
- In some sea creatures, it serves as a boneless skeleton
- Bones are formed from cartilage
- Elastic cartilage
- Ears
- Tip of nose
- Epiglottis
- Ears
- Hyaline cartilage
- Ends of long bones/joints - auricular
- Costal cartilages at rib ends
- Nose
- Trachea
- Larynx
- Ends of long bones/joints - auricular
- Fibrocartilage
- Intervertebral disks
- Pubic symphysis
- Knee joints
- Intervertebral disks
- The most common type of connective tissue in the body
- Highly elastic
- Matrix consists of loosely woven fibers from the protein collagen
- Holds tissues and organs in place
- Stores energy in the form of globules of fat (adipocytes)
- Provides insulation to regulate body temperature
- Forms padding to support/protect organs
- Gel-like matrix
- All 3 fiber types, but sparse
- Food reserves for fuel/energy
- Found in the breasts
- Gel-like matrix
- All 3 fiber types
- Phagocytes
- White blood cells
- Found in ligaments and tendons that hold bones together
- Forms scar tissue (fibroblasts)
- A few elastin fibers
- Ground Substance
- Glycoproteins
- Large polysaccharides
- Liquid or gel-like
- May be quite hard (bones or cartilage)
- Found in cavities in the matrix called lacunae
- Fibers (support)
- Collagenic (white)
- Elastic (yellow)
- Reticular (fine collagen)
- Network of fibers in a loose, ground substance
- Lymph nodes, bone marrow, spleen
- Network of fibers in a loose, ground substance
MUSCLE TISSUES:
Muscle tissue is specialized for movement and is able to contract (shorten) or extend (lengthen). There are several types of muscle tissue:
a) Skeletal Muscle
a) Skeletal Muscle
- This is the flesh of the body that produces physical movement, facial expressions, motion
- It is under voluntary control (conscious)
- Contractions move bones and limbs and body parts
- Cells are elongated and have multiple nuclei
- The tissue is striated ("striped" appearance)
- Found mostly in the internal organs (digestive tract, uterus in females, urinary tract, blood vessels)
- Striations are absent
- Cells have a single nucleus and are elongated and shaped like spindles
- Under involuntary control
- Only located in the heart
- Contracts to pump blood to the lungs, back to the heart, then to the tissues of the body
- Striated and branching cells with a single nucleus
- Cells interact with each other at specialized junctions referred to as intercalated discs
- Under involuntary control
NERVOUS TISSUE:
Nervous tissue consists mostly of two types of cells:
- Neurons
- Specialized cells that receive stimuli and send out or conduct electrical impulses to all areas of the body
- Communicate
- Nervous system function
- Cell body (dendrite) with dendritic processes to receive stimuli and contains a nucleus and cytoplasm
- Axon: long extension up to 3 feet long, or 1 meter, that sends an impulse over a long distance
- Neuroglia
- Support and protect and insulate neurons