Anatomy and Physiology I Exam 2 UWEC

Histology

the study of tissues and how they are arranged into organs​

Tissue

a group of similar cells and cell products working together to perform a specific role in an organ

Matrix (extracellular material)

Is composed of:​Fibrous proteins​, Clear gel called ground substance​

Mesoderm

This layer becomes gelatinous tissue called mesenchyme​ in embryo

* Wispy collagen fibers and fibroblasts in gel matrix​
* Gives rise to cartilage, bone, blood, muscle​

Ectoderm

(outer) ​Gives rise to epidermis and nervous system​ in an embryo

Endoderm

In an embryo, gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands, among other things​

Longitudinal Section

Tissue cut on its long axis​

Cross section/transverse section

Tissue cut perpendicular to long axis of organ​

Oblique section

Tissue cut at angle between cross and longitudinal sections

Smear

tissue is rubbed across a slide- ex. blood

Spread

some membranes and cobwebby tissues are laid out on a slide- ex. areolar tissue

Organ

structure with discrete boundaries that is composed of two or more tissue types​

Avascular

Does not have blood vessels, usually nourished by underlying connective tissue​

Epithelia

Sheets of __**closely**__ adhering cells, one or more cells thick. Covers body surfaces and lines body cavities​, constitutes most glands

Epithelial

Functions of ____ Tissue:

Protect deeper tissues from injury and infection​, Produce and release chemical secretions, Excrete wastes​, Absorb chemicals including nutrients​, Sense stimuli​

Basal Surface

surface of epithelial cell facing the basement membrane​

Apical Surface

surface of epithelial cell that faces away from the basement membrane​

Basement membrane

Layer between an epithelium and underlying connective tissue​. Collagen, reticular proteins, glycoproteins, other protein-carbohydrate complexes​

Simple Epithelia

Contain one layer of cells​, Named by shape of cells, All cells touch basement membrane​

Stratified Epithelia

Contain more than one layer​, Named by shape of apical cells​, Some cells rest on top of others and do not touch basement membrane​

Goblet Cells

wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia​

Simple squamous epithelium

Single row of thin cells​, Permits rapid diffusion or transport of substances​, Secretes serous fluid​

Locations: alveoli, glomeruli, endothelium, and serosa​

Simple cuboidal epithelium

Single layer of square or round cells, ​Absorption and secretion, mucus production and movement​

Locations: liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules​

Simple columnar epithelium

Single row of tall, narrow cells​, Oval nuclei in basal half of cell​, Brush border of microvilli, ciliated in some organs, may possess goblet cells​, Absorption and secretion; secretion of mucus

Locations: lining of GI tract, uterus, kidney, and uterine tubes​

Pseudostratified Eplithelium

Looks multilayered, but all cells touch basement membrane, Nuclei at several layers​, Has cilia and goblet cells​, Secretes and propels mucus ​

Locations: respiratory tract and portions of male urethra​

Keratinized stratified squamous​

stratified squamous epithelia on skin surface, **abrasion/friction resistant**

Multiple cell layers; cells become flat and scaly toward surface​ Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms​

Locations: epidermis; palms and soles heavily keratinized​

Nonkeratinized stratified squamous​

stratified squamous epithelia that lacks surface layer of dead cells​, Same as keratinized epithelium without surface layer of dead cells​, Resists abrasion and penetration of pathogens​

Locations: tongue, oral mucosa, esophagus, and vagina​

Stratified cuboidal epithelium

Two or more cell layers; surface cells square or round, Secretes sweat; produces sperm, produces ovarian hormones​

Locations: sweat gland ducts; ovarian follicles and seminiferous tubules

Transitional epithelium (Urothelium)

Multilayered epithelium with surface cells that change from round to flat when stretched​, Allows for filling of urinary tract​

Locations: ureter and bladder​

Cell junctions

connections between two cells, most cells are anchored to each other or their matrix ​

Tight Junction

linkage between two adjacent cells by transmembrane cell-adhesion proteins (velcro), don’t want anything to squeeze in between cells, Seals off intercellular space, making it difficult for substance to pass between cells​

Desmosome

patch that holds cells together (like a clothing snap)​, Keeps cells from pulling apart—resist mechanical stress​, bends instead of breaking

Hemidesmosomes

Anchor basal cells of an epithelium to underlying basement membrane​. Epithelium cannot easily peel away from underlying tissues

Gap (communicating) junction

formed by ring-like connexons​, Connexon consists of six transmembrane proteins arranged like segments of an orange around water-filled pore​, Ions, nutrients, and other small solutes pass between cells​

Located in cardiac and smooth muscle, embryonic tissue, lens and cornea​

Gland

__**cell or organ that secretes**__ substances for use elsewhere in the body or releases them for elimination from the bod

Endocrine glands

have no ducts; secrete hormones directly into blood

Hormones

chemical messengers that stimulate cells elsewhere in the body​

Exocrine gland

maintain their contact with surface of epithelium by way of a duct 

Unicellular gland

Gland found in an epithelium that is predominantly nonsecretory, Can be exocrine or endocrine​

Serous gland

Produce thin, watery secretions​

Mucous gland

Produce glycoprotein, **mucin**, which absorbs water to form mucus​

Mixed glands

Contain both serous and mucous cell types and produce a mixture of the two types of secretions- salivary, lacrimal​

Apocrine secretion

lipid droplet covered by membrane and cytoplasm buds from cell surface​

Merocrine secretion

(used by eccrine glands) uses vesicles that release their secretion by exocytosis. **Lowest Lipid concentration**​

Holocrine secretion

cells accumulate a product until they disintegrate

Cutaneous membrane

(the skin)—largest membrane in the body

Mucous membrane

(__**mucosa**__) lines passages that open to the external environment (example: digestive tract)​

Serous membrane

(serosa) internal membrane​, Double membrane w/ a watery liquid​

Hypertrophy

Enlargement of preexisting cells. Muscle growth through exercise​

Neoplasia

development of a tumor (neoplasm)​

Hyperplasia

growth through cell multiplication​

Metaplasia

Changing from one type of mature tissue to another. Simple cuboidal tissue of vagina before puberty changes to stratified squamous after puberty

Differentiation

development of more specialized form and function by unspecialized tissue​

Stem cells

Undifferentiated cells that are not yet performing any specialized function​. Have potential to differentiate into one or more types of mature functional cells​

Developmental plasticity

ability of a stem cell to give rise to a diversity of mature cell types​

Toti potent

have potential to develop into any type of fully differentiated human cell including accessory organs of pregnancy

Pluripotent

can develop into any type of cell in the embryo (but not accessory organs of pregnancy)​

Multipotent

able to develop into two or more cell lines (example: bone marrow stem cells)​

Adult stem cells

undifferentiated cells found in mature organs​

Induced Pluripotent Stem Cell(IPS Cell)

Start as a multipotent stem cell, reprogrammed to mimic a pluripotent stem cell.​

Regeneration

replacement of dead or damaged cells by the same type of cell as before​

Fibrosis

replacement of damaged cells with scar tissue ​

Atrophy

shrinkage of a tissue through loss in cell size or number​

Necrosis

pathological tissue death due to trauma, toxins, or infections​

Infarction

sudden death of tissue when blood supply is cut off​

Gangrene

tissue necrosis due to insufficient blood supply (usually involves infection)​

Apoptosis

Programmed cell death. Normal death of cells that have completed their function and best serve the body by dying and getting out of the way​

Connective tissue

a diverse, abundant type of tissue in which cells occupy __**less space**__ than matrix​, Supports, connects and protects organs, Highly variable vascularity​

Connecting organs

tendons and ligaments​

Support

bones and cartilage​

Physical protection

cranium, ribs, sternum​

Immune protection

white blood cells attack foreign invaders​

Storage

fat, calcium, phosphorus​

Transport

blood tissue

Movemenet

bones provide lever system​, allowing for ____________

Heat production

metabolism of brown fat in infants​

Fibroblasts

produce fibers and ground substance of matrix​

Macrophages

phagocytize foreign material and activate immune system when they sense foreign matter (antigens)​

Plasma cells

synthesize antibodies (proteins)​

Mast cells

* often found alongside blood vessels​
* Secrete heparin to inhibit clotting​
* Secrete histamine to dilate blood vessels​

Leukocytes

white blood cells​

Adipocytes

store triglycerides (fat molecules)​

Collagenous fibers

* Collagen is most abundant of the body’s proteins—25%​
* Tough, flexible, and stretch-resistant​
* Tendons, ligaments, and deep layer of the skin are mostly collagen

Reticular fibers

* Thin collagen fibers coated with glycoprotein​
* Form framework of spleen and lymph nodes

Elastic fibers

Thinner than collagenous fibers​

Branch and rejoin each other​

Made of protein called elastin​

Allows stretch and recoil​

Glycosaminoglycans (GAGs)

Long polysaccharides composed of amino sugars and uronic acid (disaccharides)​

Regulate water and electrolyte balance of tissues​

Areolar tissue

loosely organized fibers, abundant blood vessels, and a lot of seemingly empty space​, general adhesive

Reticular Tissue

* Mesh of reticular fibers and fibroblasts​
* Forms supportive stroma (framework) for lymphatic organs​

Dense regular connective tissue

Densely packed, parallel collagen fibers​

Compressed fibroblast nuclei ​

Elastic tissue forms wavy sheets in some locations​

Tendons attach muscles to bones and ligaments hold bones together

Dense Irregular Connective Tissue​

Densely packed, randomly arranged, collagen fibers and few visible cells​

Withstands unpredictable stresses​

Locations: deeper layer of skin; capsules around organs​

Adipose tissue

tissue in which adipocytes are the dominant cell type

Fat

______ is the body’s primary energy reservoir​

White fat

* Specimens resemble chicken wire​
* Provides thermal insulation​
* Cushions organs such as eyeballs, kidneys

Brown fat

* Color comes from blood vessels and mitochondrial enzymes​
* Functions as a heat-generating tissue​

Chondroblasts

cartilage cells that produce the matrix that will trap them

Chondrocytes

cartilage cells that are trapped in lacunae (cavities)​

Cartilage

* Stiff connective tissue with flexible matrix​
* Gives shape to ear, tip of nose, and larynx​
* No blood vessels​
* Matrix rich in GAGs and contains collagen fibers

Hyaline cartilage

Cartilage with clear, glassy appearance because of __***fineness***__ of collagen fibers​. Eases joint movement, holds airway open, moves vocal cords, growth of juvenile long bones. Slippery. ​

Elastic cartilage

* Cartilage containing abundance of __**elastic**__ fibers in many different directions ​
* Covered with perichondrium​
* Provides flexible, elastic support​

Perichondrium

sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage (not articular cartilage)​