Anatomy chapter 3

Fibroblasts

important for secretion of collagen & elastin

Surface epithelium: Arrangement of layers

simple: single layer stratified: several layers pseudostratified: single stretched layer that appears like multiple layers

Nervous tissue

- Neuron and Glial cells are important to nervous tissue - produce internal and external responses through electrical impulses that cause muscular contraction or secretion of glands.

Nomenclature examples: Arrangement of layers and Cell shape

- Simple squamous , Simple cuboidal , Simple columnar - Stratified squamous. stratified cuboidal, stratified columnar - Pseudostratified columnar - Transitional is always stratified.

Surface epithelium

- continuous sheets of one or more layers of cells - forms outer covering of skin and some internal organs - forms inner lining of blood vessels, ducts and body cavities - forms interior of respiratory, digestive, urinary and reproductive systems

Merocrine secretion

- also known eccrine (most common type) Secretion Process: ER > golgi complex > secretory vesicle > secretion

Basal surface

- anchors epithelium to basement membrane through hemidesmosomes

stratified columnar epithelium

- apical layer has cells that are columnar shape Location: 1) lines part of urethra 2) esophageal glands 3) anal mucus membrane 4) conjunctiva of the eye Function: protection and secretion

ciliated pseudostratified columnar epithelium

- appears to have several layers because of stretched nuclei levels. Location: 1) lines airways of most of the upper respiratory tract Function: secretes mucus that traps foreign particles; cilia sweeps away mucus for eventual elimination from the body.

nonciliated pseudostratified columnar epithelium

- appears to have several layers because of stretched nuclei levels. Location: 1) lines epididymis 2) larger ducts of many glands such as parotid gland 3) parts of male urethra Function: absorption and secretion

Muscular tissue

- arranged in a way that help with contraction and generation of force. - leads to movement of body - generates heat that warms up body

Reticular lamina

- closer to connective tissue - made up of collagen secreted by specific cells in connective tissue known as fibroblasts.

Basal lamina

- closer to epithelium - formed by proteins such laminin and collagen secreted by epithelial cells

Fibers and there main function?

- collagen fibers - reticular fibers - elastic fibers function: to support and strengthen the connective tissue

Gap junctions

- connexons join together to create tiny tunnels that form gaps between adjacent membranes. - allow ions and small molecules to freely pass between adjacent cells - allow electrical impulses to pass rapidly from one cell to the other - abundant in cardiac and smooth muscle tissue as well as some nervous tissue.

Stratified squamous eputhelium

- consist of two or more layers Location: 1) keratinized = superficial layer of skin 2) nonkeratinized = lines wet surfaces such as the mouth, esophagus, parts of pharynx, vagina and covers tongue. Function: protection against abrasion, water loss, ultraviolet radiation and foreign invasion. Both types of stratified squamous epithelium form first line of defense against microbes.

Liquid connective tissue

- contains an extracellular matrix that is going to be liquid found in blood and lymph

Epithelial tissue

- covers body surfaces - lining of hollow organs, body cavities and ducts - can form mucus glands

Apocrine secretion

- ex: mammary gland - ER > golgi apparatus > vesicles are released with part of plasma membrane (pinches off).

connective tissue proper

- flexible and viscous ground substance with abundant fibers

Basement membrane

- formed by basal lamina and reticular lamina - Anchors the epithelium to the connective tissue - surface for epithelial cell migration - growth and wound healing - restrict passage of larger molecules - participates in blood filtration in kidneys

Reticular fiber

- formed by collagen but thinner than collagen fibers - glycoprotein coating that holds them together - provide support for blood vessels - form network around cells to support cells in some of the tissues (adipose tissue, nerve fibers, smooth muscle tissues, reticular connective tissue). - spleen & lymph nodes receive support - form bottom layer of basement membrane

Mesenchyme connective tissue

- irregularly shaped mesenchymal cells Location: exclusively in embryo Function: forms almost all other types of connective tissue

Holocrine secretion

- mature cells die and become secretory product - replaced by stem cells ex: found in sebaceous gland of skin

Lateral surfaces

- on each side of the cell - contain the structures that keep cell together (tight junctions, Adherens junctions, desmosomes, gap junctions)

Components of connective tissue: Cells

- originate from mesenchymal cells that can differentiate - Major type of CT cells will end in -blast (bud or sprout) - when they differentiate the suffix turns to -cyte (not much capacity in cell division) but they monitor extra cellular matrix

Connective tissue

- protects and supports the body & and its organs - binds organs together - store energy reserves as fat - provides immunity from disease causing organisms due to different immunological cell types located in tissue.

Hemidesmosomes (half desmisome)

- provides strong attachment between cells and extracellular materials such as the basement membrane of epithelial tissue. - most abundant in tissues that undergo frictional or abrasive forces.

Transitional epithelium (uroepithelium)

- relaxed looks (stratified cuboidal) as it is stretched it seems (stratified squamous) Location: 1) lines urinary bladder and portions of ureters and urethra Function: allows the urinary organs to stretch and hold a variable amount of fluid without rupturing.

Endocrine glands

- secretions called hormones - enter the interstitial fluid and then diffuse directly into blood stream without flowing through a duct. Function: hormones regulate many metabolic and physiological activities to maintain homeostasis Location: PAT (pituitary, adrenal, thyroid) glands

Exocrine glands

- secretory products are released into ducts that empty onto the surface. (ex: skin surface). Function: produce substances such as sweat, oil, earwax, saliva, digestive enzymes. Location: POT ( pancreas, ovaries, testes) MESOES (mucus, enzymes, sweat, oil, earwax, saliva)

Simple squamous epithelium

- singe layer of flat cells Location: 1) endothelium = lines the heart, blood vessels, and lymphatic vessels. 2) Mesothelium: forms epithelial layer of serous membrane - Also found in the air sacs of lungs, glomerular capsule of kidneys, and inner surface of the tympanic membrane (eardrum) Function: Present at sites where the processes of filtration (such as blood filtration in the kidneys), diffusion (such as diffusion of oxygen into blood vessels of lungs), and secretions (in serous membrane) occur.

Nonciliated simple columnar epithelium

- singe layer of nonciliated column like cells with oval nuclei near base of cells Location: 1) Lines the GI tract (stomach to anus) 2) ducts of many glands 3) gallbladder Function: capable of higher level of secretion and absorption than cuboidal cells. secreted mucus serves as lubricant for the linings of the digestive, respiratory, reproductive tract and most of urinary tract.

Ciliated simple columnar epithelium

- single layer of ciliated columnar like cells with oval nuclei near base of cells. Location: 1) lines some bronchioles (small tubes) of respiratory tract 2) uterine fallopian tubes 3) uterus 4) some paranasal sinuses 5) central canal of spinal cord 6) ventricles of the brain Function: mostly a form of transportation 1) foreign particles toward the throat where they can be coughed up, swallowed or spit out. 2) oocytes expelled from ovaries through the uterine tubes into uterine.

Simple cuboidal epithelium

- single layer of cubed shaped cells Location: 1) covers surface of ovary 2) lines anterior surface of capsule of lens of the eye 3) forms the pigmented epithelium at the posterior surface of the retina of the eye 4) lines the kidney tubules and smaller ducts of many glands 5) makes up secretory portion of some glands such as the thyroid gland 6) duct glands such as the pancreas Function: secretion and absorption

Elastic fiber

- smaller in diameter compared to collagen - come together to form a network to support connective tissue - formed by elastin; secreted by fibroblasts - surrounded by glycoprotein called fibrillin - able to stretch 150% of their relaxed length and return to original shape after stretching (elasticity).

Collagen fibers

- strong and resist pulling and stretching force - not stiff - formed by collagen; secreted by fibroblasts - most abundant protein in body

supportive connective tissue

- support soft tissue of the body

Adherens junction

- transmembrane proteins anchored to a dense plaque of proteins inside the cell connect the adjacent cell membranes together. - microfilaments extend from the plaque into the cytosol of the cell. - Adhesion belts help resist the separation of epithelial tissue.

Desmosome

- transmembrane proteins attached to intracellular plaques form connecting bridges between adjacent cells. -Intermediate filaments extend into the cytosol of each cells providing stability to tissues. - abundantly found in epidermis of the skin and between muscle cells of the heart

Stratified cuboidal epithelium

- two or more layers of cells that are cube shaped (fairly rare) Location: 1) ducts of adult sweat glands and esophageal glands 2) male urethra Function: protection and limited secretion and absorption

Tight junctions

- web-like strips of proteins that fuse together adjacent plasma membranes. - protect underlying tissues from harmful substances by restricting the movement of those substances in the spaces between cells. - found in tissue lining the surface of organs and body cavities such as the (stomach, intestine, urinary bladder).

Mucous (mucoid) connective tissue

- widely scattered fibroblasts embedded in a viscous Location: umbilical cord of fetus Function: support

Apical (free) surface

- will not be attached to anything - facing the outside (skin) or can be facing body cavities - in glands it will be facing tubular duct were secretions pass through - can contain specialized structure like (cilia for locomotion or microvilli that increase surface area for absorption)

Classification of connective tissue

1) Embryonic connective tissue 2) mature connective tissue

Four major types of tissues

1) Epithelial tissue 2) Connective tissue 3) Muscular tissue 4) Nervous tissue

Cells that help with immune response

1) Macrophages = originate from monocytes; destroy bacteria by phagocytosis 2) Eosinophils = respond to allergic reactions 3) Neutrophils = most of in the body; destroy smaller microbes by phagocytosis 4) Mast cells = run along blood vessels producing histamine; dilates small blood vessels to circulate more blood. 5) Plasma cells = develop B lymphocytes which give rise to antibodies which are important for destruction of pathogens

Embryonic connective tissues

1) Mesenchyme connective tissue 2) Mucous connective tissue BOTH before birth

Main functions of epithelium

1) Protects 2) Secretes 3) Absorbs 4) Excretes 5) Filtration

Five types of cell junctions

1) Tight junctions 2) Adherens junctions 3) Desmosomes 4) Hemidesmosomes 5) Gap junctions

Mature connective tissue

1) connective tissue proper 2) supporting connective tissue 3) liquid connective tissue

Absorbs how?

Absorbs nutrients from GI tract

Epithelial vs Connective tissue

Epithelial tissue: 1) cells are tightly packed together in continuous sheets and little to no extracellular matrix 2) avascular (no blood vessels) 3) Cells have lateral surfaces (one on each side), apical (free) surface, and basal surface 4) polarity (organelles inside the cell are unevenly distributed) 5) high capacity for cell division Connective tissue: 1) scattered cells with large amounts of extracellular matrix 2) vascular (blood vessels) 3) can not be classified as simple or stratified because cells are spread out

Excretes how?

Excretes substances in urinary tract

Filtration how?

Filtrates what enters the body or organs

Exocrine gland: Functional classification

MAH Merocrine Apocrine Holocrine

Secretes how ?

Secretes mucus, hormones and enzymes

Exocrine gland: Structural classification

Simple = unbranched Compound = branched tubular and acinar (more rounded)

Protects how ?

by covering external surfaces

Components of connective tissue: Extracellular Matrix

consist of: - Protein fibers Ground substance: - may be blood, gelatinous or bone - cells = supports and binds them together - stores water - provides medium for exchange of substances between blood & cells

Adipocytes

fat cells found below the skin or around organs (ex: heart and kidney); form and cover abdominal cavity

Keratin

fibrous intracellular protein that helps protect the skin and underlying tissues from heat, microbes and chemicals.

Microvilli

finger like cytoplasmic projections that increase surface area of plasma membrane

Goblet cells

modified columnar epithelial cells that secrete mucus

Connective tissue

one of the most abundant and widely distributed tissues in the body functions: - supports and strengthens other body tissues - protects and insulates internal organs - blood (fluid connective tissue); serves as the major transport system within the body. - adipose (fat) tissue; primary location of stored energy reserves - main source of immune response

Glandular epithelium

specialized epithelial cells organized to form glands that secrete substances into ducts, onto a surface or into the blood. 1) endocrine glands 2) exocrine glands

Surface epithelium: Cell shape

squamous: flat cuboidal: cube like columnar: rectangular column transitional: located in urinary bladder: starts rounded and turns squamous when bladder is full.