BIO 131 Exam 2

Decubitus ulcer

Bed sore or pressure sore - form of dry gangrene from continual pressure on skin

Dry gangrene

common complication of diabetes

Wet gangrene

liquefication of internal organs with infection

Gas gangrene

usually from infection of soil bacterium that results in hydrogen bubbles in tissues

Osteogenesis imperfecta (bone brittle disease)

Results from a defect in collagen deposition. Bones break very easy

Rickets

Disease caused by mineral deficiency and resulting in soft, deformed bones

4 Major/Broad Categories of Tissues

Epithelial Tissue

Connective Tissue

Muscle Tissue

Nervous Tissue

Organ

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

Tissue

Group of similar cells and cell products that work together to perform a specific role in an organ

Ground substance

Clear gel or tissue fluid/ extracellular fluid/ intracellular fluid

Ectoderm

Gives rise to epidermis and nervous system (outer)

Endoderm

Gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands, among other things (inner)

Mesoderm

becomes gelatinous tissue called mesenchyme (middle)

Fixative

Prevents decay (formalin)

Histological sections

tissue is sliced into thin sections that are one or two cells thick

Stains

tissue is mounted on slides and artificially colored with histological stain for examination

Longitudinal section (LS or l.s.)

tissue section is cut on it’s long axis

Cross section (c.s. or x.s.) or Transverse section (t.s.)

Tissue cut perpendicular to the long axis of the organ

Oblique section

tissue is cut at an angle between cross and longitudinal sections

Smear

tissue is rubbed across a slide

Spread

membranes and cobwebby tissues are laid out on the slide

Functions of muscular tissue

Exert physical force on other tissues and organs

Creates movement involved in body and limb movement, digestion, waste elimination, breathing, speech, and blood circulation

Important source of body heat

Skeletal muscle

Made of muscle fibers (long thin cells)

Most attach to bone

Multiple nuclei adjacent to plasma membrane

Striated and voluntary

Cardiac muscle

Limited to the heart wall

Cardiomyocytes are short and branched with 1 central nucleus (joined end to end by intercalated discs that provide electrical and mechanical connection)

Striated and involuntary

Smooth muscle

Made of fusiform uninuclear cells lacking striations

Involuntary

Most is visceral muscle (making up parts of walls of hollow organs)

Functions of Connective Tissue

Connecting organs: tendons and ligaments

Support: bone and cartilage

Physical protection: cranium, ribs, sternum

Immune protection: white blood cells attack foreign invaders

Movement: bones provide lever system

Storage: fat, calcium, phosphorus

Heat production: metabolism of brown fat in infants

Transport: blood

Fibroblasts

Produce fibers and ground substance

Macrophages

phagocytize foreign material and immune system when they sense foreign matter

Leukocytes

white blood cells

Mast cells

help with inhibiting clotting and dilating blood vessels

Adipocytes

fat molecules

Collagenous fibers

Collagen is most abundant of the body’s proteins

Tough, flexible, and stretch resistant

Tendons, ligaments, and deep layer of the skin are mostly collagen; less visible in the matrix of cartilage and bone

Reticular Fibers

Thin collagen fibers coated with glycoprotein

Form framework of spleen and lymph nodes

Elastic fibers

Thinner than collagenous fibers, made of protein elastin

Branch and rejoin each other

Allows stretch and recoil

Dense Regular Connective Tissue

Densely packed, parallel collagen fibers

Compresed 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 stress

Locations: deeper layer of skin; capsules around organs

Areolar tissue

Tissue with loosely organized fibers (that run in random directions, found in nearly every part of the body, and the epithelium rests on a layer of areolar tissue) with abundant blood vessels and a lot of empty space

Reticular tissue

Tissue that forms a supportive stroma or framework for lymphatic organs

Connective Tissue Ground Substance Components

Glycosaminoglycans

Proteoglycans

Adhesive glycoproteins

Glycosaminoglycans (GAGs)

Long polysaccharides composed of amino sugars and uronic acid

Regulate water and electrolyte balance of tissues

Ex: chondroitin sulfate (most abundant and helps with stiffness of cartilage), heparin, and hyaluronic acid

Proteoglycans

Gigantic molecules shaped like bottle brushes

Form gravy like colloids that hold tissues together

Adhesive glycoproteins

Protein-carbohydrate complexes

Bind components of a tissue together

What is the dominant cell type in adipose tissue?

Adipocytes

Brown Fat

In fetuses, infants, children, hibernating animals

Color comes from blood vessels and mitochondrial enzymes

Functions as a heat generating tissue

White fat

Main type (only fat in adults)

Specimens resemble chicken wire

Provides thermal insulation

Cushions organs such as eyeballs, kidneys

Contributes to body contours via subcutaneous fat - female breasts and hips

Cartilage

Stiff connective tissue with flexible matrix

Composed of chondroblasts (cells that produce the matrix that will trap them) and chondrocytes (cells that are trapped in lacunae)

Types of cartilage

Hyaline Cartilage, Fibrocartilage, Elastic cartilage

Hyaline cartilage

Clear, glassy appearance because of fineness of collagen fibers

Eases joint movement, holds airways open, moves vocal cords, growth of juvenile long bones

Locations: articular cartilage, costal cartilage, trachea, larynx, fetal skeleton

Fibrocartilage

Cartilage containing large, coarse bundles of collagen fibers

Resists compression and absorbs shock

Locations: pubic symphysis, menisci, and intervertebral discs

Elastic Cartilage

Cartilage containing abundance of elastic fibers

Covered with perichondrium

Provides flexible, elastic support

Locations: external ear and epiglottis

Spongy Bone

Porous appearance

Delicate struts of bone: trabeculae

Covered by compact bone

Locations: heads of long bones and in middle of flat bones such as the sternum

Compact Bone

Denser, calcified tissue with no visible spaces

More complex arrangement

Cells and matric surround vertically oriented blood vessels in long bones

Osteon

Central canal and its surrounding lamellae

Periosteum

Tough fibrous connective tissue covering the whole bone

In bone, blood vessels and nerves travel through

Central canal

Blood

Fluid connective tissue

Plasma

Blood’s ground substance

Formed elements: cells and cell fragments

Erythrocytes: red blood cells (RBSs): transport O2 and CO2

Leukocytes: white blood cells (WBCs): defend against infection and disease

—-Neutrophils, eosinophils, basophils, lymphocytes, monocytes

Platelets: cell fragments involved in clotting

What are the excitable tissues?

Nervous tissue

Muscle tissue

Excitability

Ability to respond to stimuli by changing membrane potential

Membrane potential

Electrical charge difference that occurs across the cell membrane

In nerve cells

Changes in voltage result in rapid transmission of signals to other cells

In muscle cells

Changes in voltage result in contraction, shortening of the cell

Neurosoma (cell body)

Houses nucleus and other organelles

Controls protein synthesis

Dendrites

Multiple short, branched processes

Receive signals from other cells

Transmit messages to the neurosoma

Axon

Sends outgoing signals to other cells

Can be more than a meter long

Each of these is a function of muscular tissue except:

a. body heat

b. exert physical force

c. contract in response to stimuli

d. send signals to the brain

e. none of these

d. send signals to the brain

When a tissue section is cut perpendicular to the long axis of the organ is what type of tissue section?

a. Longitudinal section

b. Oblique section

c. Hyperactive section

d. Cross-section

d. Cross-section

Name a place that hyaline cartilage may be found

Articular cartilage, costal cartilage, trachea, larynx, fetal skeleton

The type of cells that phagocytize foreign material and activate the immune system when they sense foreign matter or antigens are known as

Macrophages

What is the name of the long polysaccharides composed of amino sugars and uronic acids that aids in regulating water and electrolyte balance of tissues?

Glycosaminoglycans (GAGs)

Sheets of closely adhering cells, one or more cells thick are known as what type of tissue? What do they cover?

Epithelia

Covers body surfaces and lines body cavities

Upper surface usually exposed to the environment or an internal space in the body

Constitutes most glands

Basal surface

Cell surface facing the basement membrane

Apical surface

Cell surface that faces away from the basement membrane

Lateral surface

Cell surface between the basal and apical surface, “sidewall”

Goblet cells

Wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia

Simple Squamous

lungs, blood vessels, alveoli, glomeruli, endothelium, serosa

Simple cuboidal

Liver, thyroid, mammary and salivary glands, bronchioles, sweat glands, and kidney tubules

Simple columnar

Lining of GI tract, stomach, uterus, kidney, and uterine tubes

Pseudostratified Epithelium

Respiratory tract and portions of male urethra

Stratified squamous

sweat glands in the skin

Keratinized stratified squamous

epidermis, palms, and soles

Non-keratinized stratified squamous

tongue, oral mucosa, esophagus, and vagina

Cellular Junctions

Allows cells to communicate with each other, resist mechanical stress, and control what moves through the gaps between them

Tight junction

Zipper-like, interlocking linkage between two adjacent cells by transmembrane cell-adhesion proteins. Seals off intercellular space, making it difficult for substance to pass between cells.

Desmosomes

Patch that holds cells together and keeps cells from pulling apart (resists mechanical stress)

Hemidesmosomes

Half a desmosome

Gap junctions

Formed by ring-like connexons that consist of 6 subunits (transmembrane proteins) arranged like segments of an orange around a water-filled pore. Ions, nutrients, and other small solutes pass between cells.

Glands

Secrete substances for use elsewhere in the body or for elimination from the body

Excretion

Waste product

Secretion

Product useful to the body

Exocrine glands

Maintain their contact with the surface of epithelium by way of a duct

Surfaces can be external (ex: sweat, tear glands) or internal (pancreas, salivary glands)

Endocrine glands

Have no ducts; secrete hormones directly into the blood

Ex: thyroid, adrenal, and pituitary glands

Merocrine

Vesicles that release their secretion by exocytosis

Apocrine

Liquid droplet covered by membrane which buds from the cell surface

Holocrine

cells accumulate a product until they disintegrate and a mix of cell fragments and synthesized substances are released

Tissue Growth

increasing the number of cells or size of existing cells

Hyperplasia

growth through cell multiplication

Hypertrophy

enlargement of preexisting cells

muscle growth through exercise

accumulation of body fat

Neoplasia

development of a tumor (neoplasm)

benign or malignant

composed of abnormal, nonfunctional tissue

Tissue development

tissue changing types within certain limits