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