Ch. 4 Lecture
Loose connective tissue
- lots of light coming through - areolar - adipose
Specialized connective tissue types
- Cartilage - blood - bone
Epithelial tissue
- Covers body surfaces - lines body organs, body cavities & ducts - forms glands - arranged in sheets and are densely packed - attach to a BASEMENT MEMBRANE - mitosis occurs frequently - outer edge is called apical(free) surface
Membranes
- Flat sheets of pliable tissue that cover or line a part of the body - consist of an epithelial layer and a connective tissue layer underneath - epithelial membranes: mucous, serous, cutaneous - synovial membranes
Tubular secretory parts (multicellular exocrine gland)
Tubular
Transitional cells
change shape; the apical cells are cuboidal when the tissue is relaxed and squamous when the tissue is stretched
Cuboidal epithelium
cube shaped cells
Fibroblasts
large flat cells that move through connective tissue and secrete fibers and ground substance
Dendrites
- Branchlike parts of a neuron that are specialized to receive information
Mast cells
- Abundant along blood vessels - produce HISTAMINE, which dilates small blood vessels during inflammation and kills bacteria
Neuroglia
- PROTECT and SUPPORT neurons - the little dots surrounding neuron
Cutaneous membrane
- covers the surface of the body - skin is more of dermis than epidermis
simple columnar epithelium
- absorbing - digestive system
Tight junction
- area where the plasma membranes of adjacent cells are fused together - protect underlying tissues from harmful substances by restricting movement of substances - prevents organs from leaking into bloodstream
Stratified squamous epithelium
- areas for protection - skin - lining ESOPHAGUS
Skeletal tissue
- attached to bones - STRIATED - VOLUNTARY (somatic nervous system controls it) - MANY NUCLEI (pushed to the side) - long rectangular shape
Connective tissue
- consists of cells and extracellular matrix - does not have any free surfaces - is highly vascularized and has a nerve supply - exceptions: TENDONS and CARTILAGE
Adherens junction
- created when transmembrane proteins anchor to dense plaque of proteins inside the cells and connect the adjacent cell membranes together - MICROFILAMENTS extend from the plaque into the cytosol of each cell - adhesion belts help resist separation of epithelial tissues
Electrical excitability
- debility to respond to certain stimuli by producing electrical signals, such as action potentials, which travel along the plasma membrane of a neuron or muscle fiber due to presence of specific voltage-gated channels
Nervous tissue
- detects changes - responds w/ nerve impulses (action potentials) that activate muscles and glands
4 types of tissue
- epithelial - connective - muscular - nervous
Adipose
- fat - kinda looks like water - nucleus is on the edge - used to store nutrients - provides protection/warmth around organs
Adipocytes
- fat cells that store fats - found below skin and around organs (HEART, KIDNEY)
Neurons
- have a cell body, dendrites, and axons - carry sensory OR motor information and they cam perform integrative functions - responsible for sending signals - big cell body is called SOMA
Cardiac tissue
- heart, striated, involuntary (automatic nervous system controlled), branched USUALLY ONE TO TWO NUCLEI - gap junctions connect cells (electrical communication rapid) - branching cells fit tightly together at unique junctions called INTERCALATED DISCS (allow for synchronized contraction of the heart) - can start an electrical impulse on its own
Bone
- help support - cells are compact - looks circular - rings
Cell junctions
- holds cells together - found in most epithelial cells and some muscle and nerve cells
Microvillli
- increases surface area - simple columnar - allows to increase absorbtion
Serous membranes
- line cavities that DO NOT open directly to the outside - lungs
Mucous membranes
- lines body cavities that open to the outside - digestive system (inner lining)
Synovial membranes
- lines joints - secretes synovial fluid - lots of connective tissue, less epithelial tissue
Extracellular matrix
- located between spaces between connective tissue cells - composed of FIBERS and GROUND SUBSTANCE
Cartilage
- look kinda like broken. Pills - look like they're in liquid - lots of extracellular matrix
Tendon
- looks wavy
Connective tissue types
- loose - dense - specialized
Connective tissue in MATURE stage
- loose (areolar, adipose, reticular): fibers loosely arranged between cells - dense (regular, irregular, elastic; tendons ligaments, fasciae): contains more, thicker, and more densely packed fibers and fewer cells - cartilage (hyaline, Fibrocartilage, and elastic cartilage): fewer cells, large quantities of extracellular matrix; gel like ground substance - bone (sponges and compact): supports, protects, allows movement by muscles - blood: liquid extracellular matrix
Areolar
- lots of strands/fibers - LOTS of extracellular matrix - kinda looks like wrinkled paper
Reticular fibers
- made of collagen and glycoproteins - provide support in blood vessel walls - from branching networks around various cells (fat, smooth muscle, nerve)
Ground substance
- material between cells and fibers - made of water and organic molecules - supports cells and fibers, binds them together, and provides a medium for exchanging substances between blood and cells
Connective tissue in EMBRYONIC stage
- mesenchyme: forms nearly all types of adult connective tissue - mucous: found in fetal umbilical cord
Two types of nervous tissue cells
- neurons - neuroglia/ glial cells - used to communicate signals through the body
Gap junction
- open communication channel - transmembrane proteins called connexons join together to create tiny tunnels that form gaps between adjacent membranes - allow ions and other small molecules to pass freely from one cell to another - allow electrical impulses to pass rapidly from one cell to another - abundant in types of MUSCLE tissue ( SMOOTH, CARDIAC, NERVOUS)
Connective tissue
- protects & supports body and organs - binds organs together - stores energy reserves as fat
What do the fibers in muscle tissue do?
- provide motion - maintain posture - produce heat
What do fibers in the extracellular matrix do?
- provide strength and support to a tissue - collagen fibers - elastic fibers - reticular fibers
Hemidesmosome
- provides STRONG attachments between cells and other extracellular materials such as basement membrane of epithelial tissues - most abundant in tissues that undergo constant frictional or abrasive forces
Exocrine glands (sweat)
- secrete chemical substances onto surface of a covering/lining epithelium such as the skin surface or luminous the stomach - found in swear, oil, earwax glands, salivary glands, and pancreas - produce substances such as sweat to help lower body temperature, oil, earwax, saliva, or digestive enzymes
Endocrine glands
- secrete hormones directly into the bloodstream - found in pituitary gland, pineal gland, thyroid and parathyroid glands, adrenal gland, pancreas, ovaries, testes, thymus in thoracic cavity - REGULATE many metabolic and physiological activities to maintain homeostasis
simple cuboidal epithelium
- secreting substance - found surrounding/lining something
Apocrine glands
- secretions accumulate at apical surface, then cell pinches off and releases secretions by exocytosis - milk in mammary glands; apocrine sweat glands
Holocrine glands
- secretions accumulate in cytosol, cell matures and ruptures - sebaceous glands of skin
Merocine glands
- secretions released form cell in secretory vesicles by exocytosis - most secretions in body; salivary and pancreas secretions
Desmosome
- similar to adherens junction except that INTERMEDIATE filaments extend into cytosol of each cell - help provide STABILITY to tissues - found ABUNDANTLY in EPIDERMIS of skin and BETWEEN the MUSCLE cells of the HEART
3 types of muscle tissue
- skeletal - cardiac - smooth
Muscular tissue
- specialized for contraction and generation of force - generates heat
Ligaments
- stands - really strong
Elastic fibers
- stretchable but strong fibers made of proteins, elastin and fibrillin - found in SKIN, BLOOD VESSELS, and LUNG TISSUE
Dense connective tissue types
- tendons - ligaments
Axon
- threadlike extension of a neuron that carries nerve impulses away from the cell body - usually the longest/thickest extension
Types of cell junctions
- tight junctions - adherens junctions - desmosome - hemidesmosome - gap junction
Where are tight junctions found?
- tissues lining surface of organs and body cavities such as stomach, intestines, and urinary bladder
Blood
- transports things - only type that has a fluid extracellular matrix
Smooth tissue
- vessels, airways, GI tract - SPINDLE SHAPED (looks like an eye) - NO STRIATION - INVOLUNTARY (automatic nervous system controlled) - 1 NUCLEI - lines internal organs - looks like a picture taken from a potato (fuzzy/blurry)
Eosinphils
- white blood cells that migrate to sites of PARASITIC infection and ALLERGIC reactions
Neutrophils
- white blood cells that migrate to sites of infection that destroy microbes by phagocytosis
Rounded secretory gland (multicellular exocrine gland)
Acinar
Multicellular exocrine glands
Composed of many cells that form a distinctive microscopic or macroscopic organ - sweat (sudoriferous) glands - oil (sebaceous) glands - salivary glands
Branched duct (multicellular exocrine gland)
Compound gland
Epithelial vs connective tissue
Epithelial - avascular (no blood vessels) - usually found on surface of tissue - found ADJACENT to connective tissue - tightly packed together w/ LITTLE extracellular matrix Connective - vascularized - not found on surface of tissue - few scattered cells surrounded w/ LARGE amounts of extracellular matrix
Tissue
Group of cells that function together to carry out specialized activities
pseudostratified epithelium
Multiple layers due to difference in cell height, but are really one layer.
Simple epithelial
One layer of epithelial cells
Goblet cells
Secrete mucus directly onto surface of lining epithelium
Stratified epithelial
Several layers of epithelial
Unbranched duct (multicellular exocrine gland)
Simple gland
Unicellular exocrine glands
Single cells - goblet cells
Why are NEURONS and MUSCLE fibers considered excitable cells
They exhibit electrical excitability
Columnar epithelium
Type of epithelial tissue with cylindrical cells
Gland
a single cell or a mass of epithelial cells adapted for secretion
Plasma cells
develop from B lymphocytes; secrete antibodies that attack and neutralize foreign substances
Macrophages
develop from monocytes and destroy bacteria and cell debris by phagocytosis
squamous epithelium
flat, scale-like cells
Collagen fibers
strong, flexible bundles of the protein collagen, the most abundant protein in your body