Exam 3 Review Slides Lectures 9-12 Chapters 5, 6, and 7

Types/Functions of Epithelial Tissue • Types of epithelium • Covering and Lining Epithelium

– External Surfaces, e.g., skin, Internal surfaces

• Glandular Epithelium • Functions of Epithelial Tissue

– Physical protection – Control of permeability • Secretion, Absorption, Filtration – Provide sensation – Provide specialized secretions (glands) 2

Characteristics of Epithelial Tissue • S pecialized contacts with other cells • P olarity (different ends of cell do different things) • A vascularity (no blood supply) • R egeneration (can divide to make new cells) • C ellularity (lots of cells in close contact)

Remember: Epithelial tissues always have a free surface and a basement membrane

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Basal Lamina

Formerly called: Basement membrane Two components: Lamina Lucida - glycoproteins and fine protein filaments - Barrier for passage of substances from underlying tissue into epithelium Lamina = thin layer Lamina Densa - bundles of coarse protein fibers - gives basal lamina its strength Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004

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Classification of Epithelial Tissues

Epithelial tissues are classified according to both their:

• Shape

– Squamous (Thin, flat, irregular in shape) – Cuboidal (Square or cuboidal) – Columnar (Rectangular, tall)

• Type of layering ( stratification )

– Simple (one layer) – Stratified (two or more layers) –

Note that classification of stratified epithelium is based on the shape of the superficial, not deep, layers

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Characteristics of Epithelial Tissue Specialized Contacts

Tight junction – forces substances to go through cells, rather than being able to pass between them Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Gap junction – allow rapid passage of small molecules/ions between cells Desmosome – binds cells together firmly so they stay connected

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NAME OF ET SIMPLE SQUAMOUS SIMPLE CUBOIDAL SIMPLE COLUMNAR PSEUDO STRATIFIED COLUMNAR

Review

DESCRIPTION STRUCTURE

a single layer of flattened cells a single layer of cube shaped cells with large centrally located nuclei a single layer of tall cells with basally located nuclei, goblet cells, & mucrovilli

LOCATION

linings of air sacs, capillaries, lymph vessels, body cavities; covering ventral organs linings of kidney tubules, ducts of glands lining of intestine a single layer of tall cells with scattered nuclei, cilia, & goblet cells lining of trachea, lining of fallopian tube

FUNCTION

diffusion, reduction of friction absorption, secretion protection, absorption, secretion protection, secretion 7

NAME OF ET STRATIFIED SQUAMOUS

Review

DESCRIPTION STRUCTURE LOCATION

many layers of flattened cells

FUNCTION

keratinized = epidermis; non-keratinized = lining of vagina, anus, throat, mouth protection

TRANSITIONAL

several layers of cells that change shape under pressure

GLANDULAR

simple cuboidal lining of urinary bladder and ureters Distensibility (able to stretch) lining the ducts of glands secretion 8

Review of Epithelial Tissues

• Glands are specialized epithelium – Secrete on to a surface ( exocrine ) – Secrete into a duct ( exocrine ) – Secrete into the blood ( endocrine ) • Exocrine glands have several different mechanisms of secretion – Merocrine • Release of product from vesicles by exocytosis – Apocrine • Loss of cytoplasm containing secretion; Apical portion of cytoplasm is shed – Holocrine • Entire cell is packed with secretion and then bursts 9

Membranes

A membrane is a combination of epithelium and connective tissue that covers and protects other structures and tissues. Technically, then, a membrane is an organ .

Serous

•

line body cavities that

• •

lack openings to outside reduce friction inner lining of thorax and

•

abdomen cover organs of thorax

•

and abdomen secrete serous fluid Cutaneous

•

covers body

•

skin Mucous

•

line tubes and organs

•

that open to outside world lining of mouth, nose,

•

throat, digestive tract, etc.

secrete mucus Synovial

•

surround joint cavities

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NAME OF CT MESENCHYME AREOLAR ADIPOSE RETICULAR DENSE REGULAR DENSE IRREGULAR

Review

DESCRIPTION

loose matrix of collagen fibers

LOCATION

Embryo dermis of skin

FUNCTION

gives rise to all other CT’s gel-like matrix with fibroblasts, collagen and elastic fibers closely packed adipocytes with nuclei pushed to one side by fats network of reticular fibers in loose matrix dense matrix of collagen fibers beneath ET (serous membranes around organs & lining cavities) beneath skin, breasts, around kidneys & eyeballs basement membranes, lymphatic organs tendons, ligaments diffusion, cushioning organs insulation, energy store, protection support attachment (high tensile strength) strength in several directions 11

NAME OF CT ELASTIC CT HYALINE CARTILAGE FIBRO CARTILAGE ELASTIC CARTILAGE BONE BLOOD

Review

DESCRIPTION LOCATION FUNCTION

matrix of elastic fibers chondrocytes in lacunae in amorphous matrix less firm than above lung tissue, wall of aorta durability with stretch embryonic. skeleton, costal cart, tip of nose, trachea, larynx intervertebral discs, pubic symphysis support tensile strength, shock absorber above plus elastic fibers external ear, epiglottis concentric circles of calcified matrix Bones red cells, white cells and platelets in liquid plasma in heart and blood vessels shape maintenance plus flexibility support, protection, movement, Ca ++ storage, hematopoiesis transport of nutrients, wastes & gases 12

Connective Tissue (CT) Summary Table Three main components of ALL CT: cell, fibers, ground substance Name of CT

CT Proper Cartilage

Different types of this CT

1) Areolar (Loose) 2) Dense regular 3) Dense irregular 4) Adipose 5) Reticular 6) Elastic 1) Hyaline 2) Fibrocartilage 3) Elastic

Main types of cells present

1) Fibroblasts 2) Fibroblasts 3) Fibroblasts 4) Adipocytes 5) Fibroblasts 6) Fibroblasts

Main types of fibers present

1) Collagen, Elastic 2) Collagen 3) Collagen 4) Reticular 5) Reticular 6) Elastic (All) Chondrocytes 1) Collagen (sparse) 2) Collagen (dense) 3) Elastic

Consistency of matrix

Semi-liquid

Examples of Locations

1) Skin, between muscles 2) Tendons, ligaments 3) Dermis 4) Body fat areas 5) Stroma of liver, spleen 6) Lungs, airways, arteries/heart Semi-solid, gelatinous 1) Ribs, ends of bones 2) Intervertebral disks 3) Pinna of ear, epiglottis Bone Blood Lymph 1) Dense 2) Spongy - - (All) Osteocytes 1) RBCs 2) WBCs 3) Platelets (cell fragments) Lymphocytes Collagen Fibrinogen (soluble) Reticular (in stroma of lymphoid organs) Solid (hydroxyapatite) 1) Outer portions of bone 2) Inner portions of bone Liquid Liquid Blood vessels, heart Lymph vessels

-cyte = fully differentiated; -blast = young, actively synthesizing cell

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Connective Tissue - Major Cell Types

Fibroblasts

•

fixed cell

•

most common cell; always

• • •

in CT proper large, star-shaped produce fibers produce ground substance Macrophages

•

wandering

• • •

phagocytic cell important in defense derived from circulating monocytes

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Connective Tissue Fibers

Collagenous fibers

•

thick

• • • • •

composed of collagen great tensile strength hold structures together abundant in dense CT tendons, ligaments Elastic fibers

•

bundles of microfibrils embedded

• • •

in elastin fibers branch elasticity vocal cords, air passages Reticular fibers

•

very thin collagen ous

• •

fibers highly branched form supportive networks

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glucosamine

The “Ground Substance” of CT

VERY hydrophilic!

Very active in controlling passage of substances through this portion of the matrix and keeping CT hydrated GAGs = glycosaminoglycans (negatively charged polysaccharides); a major molecule in ground substance Figures from: Alberts et al., Essential Cell Biology, Garland Press, 1998

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Tendons and Ligaments

Tendons : Connect muscle to bone Ligaments : Connect bone to bone Aponeuroses : Broad, fibrous sheets; usually attach muscle to muscle (or bone)

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CT Framework of the Body

Fascia connects the organs of the dorsal and ventral cavities with the rest of the body Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Provide : - Strength - Stability - Organ position - Conduits

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Muscle – Overview •

General characteristics

–

Elongated cells with special properties

–

Muscle cells (myocytes) = muscle fibers

–

Contractile (major property of all muscle)

–

Use actin (thin) and myosin (thick) for contraction

•

Three types of muscle tissue

–

Cardiac (involuntary)

–

Skeletal

–

Smooth

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NAME OF MUSCLE TISSUE SKELETAL MUSCLE

Review of Muscle Types

LOCATION DESCRIPTION OF STRUCTURE TYPE OF CONTROL FUNCTION

long, thin fibers with many nuclei and striations Voluntary attached to bones to move bones

SMOOTH MUSCLE

spindle shaped cells with one centrally located nucleus, lacking striations Involuntary walls of visceral hollow organs, irises of eyes, walls of blood vessels heart to move substances through passageways (i.e. food, urine, semen), constrict blood vessels, etc pump blood to lungs and body

CARDIAC MUSCLE

a network of striated cells with one centrally located nucleus attached by intercalated discs - Intercalated disks consist of gap junctions and desmosomes Involuntary 20

Nervous Tissue

• • • • •

found in brain, spinal cord, and peripheral nerves conduction of nerve impulses basic cells are neurons sensory reception neuroglial cells are supporting cells

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Introduction to Inflammation

Restoration of homeostasis after tissue injury or infections involves two processes : 1) inflammation and 2) repair .

Hallmarks of inflammation: Redness, heat, pain, swelling, and loss of function (Inflammation = ‘-itis’)

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Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

Functions of the Integumentary System •

Functions of the integument

–

Protection

(from mechanical/chemical/bacterial damage, UV radiation) –

Temperature regulation (

extreme heat, extreme cold) and

Fluid conservation

–

Excretion

– –

Vitamin D production Sensation

(touch, pressure) 23

Layers of the Epidermis - Overview

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Thick and Thin Skin

Thin (0.07-0.12 mm) (epidermal thickness) Thick (0.8-1.4 mm) (epidermal thickness) Thick skin - palms of hands, soles of feet; five epidermal layers Thin skin - everywhere else; four epidermal layers ( no s. lucidum )

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Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

Cells of the Epidermis

• Epidermis of the skin is classified as a keratinized stratified squamous epithelium • Cells of the epidermis include – Keratinocytes (90%) • Keratin – a tough, fibrous intracellular protein (protection) • Lamellar granules (waterproofing, extracellular) – Melanocytes (8%) • Produce melanin – Langerhans cells ( protection from UV radiation ) (1-2%) • Migrate to skin from bone marrow • Participate in skin’s immune response (dendritic cells) – Merkel cells (< 1%) • Least numerous; specialized epithelial cells • Function in sensation of touch 26

Skin Color

Genetic Factors

•

varying amounts and

•

type of melanin varying size/number of

•

melanin granules albinos lack melanin (but not melanocytes!) Physiological Factors

•

dilation of dermal blood vessels ( erythema )

•

constriction of dermal blood vessels (less pink, pale = pallor )

•

level of oxygenation of blood * normal = pink (fair-skinned) * low = bluish ( cyanosis )

• • •

Environmental Factors sunlight UV light from sunlamps X rays

•

carotene -> Vit A (yellow)

•

jaundice (yellow)

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Skin Color and Melanin

Dark-skinned Fair-skinned Melanocytes produce melanin - tyrosine



melanin - UV radiation up-regulates production of melanin - Caucasian vs. dark-skinned * number vs. activity * layer of epidermis Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004

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Keratin and Vitamin D

• Keratin – Protection – Water resistance • Vitamin D 3

(“sunshine vitamin”)

– After UV irradiation epidermal cells in s. spinosum and s. basale convert a cholesterol-related steroid to Vit D 3 (cholecalciferol) – Vit D 3 –  absorption of calcium and phosphorus by small intestine 29

Dermis

Papillary layer areolar connective tissue (CT) capillaries and sensory neurons - dermal papillae - fingerprints (with epi. ridges) Reticular layer dense, irregular CT - collagen fiber bundles extend upward and downward - also contains elastic fibers and cells of CT proper - accessory organs of integumentary system (from epi.) - cleavage or tension lines - flexure lines Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001

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Subcutaneous Layer

Basal lamina Stabilization of dermis INSULATION - Areolar and adipose tissue - Effect of hormones Reservoir of blood Also called ‘ hypodermis ’. This is the superficial fascia .

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Hair ( pilo )

•

epidermal cells

•

tube-like depression

•

extends into dermis

•

hair root (in dermis)

•

hair shaft (outer 1/3)

•

hair papilla

•

dead epidermal cells

• •

melanin arrector pili muscle Basal lamina (from epidermis) Nerves in root hair plexus A hair in the scalp grows for 2-5 years, about 0.33mm/day

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Hair Follicles

Types of hair : 1. Lanugo – long, blond, fine (fetal, anorexia nervosa) 2. Vellus – short, blond (children) 3. Terminal – course, pigmented (adults) Some hair color Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Hair color

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Sebaceous (Oil) Glands

•

usually associated with hair follicles

•

holocrine glands

•

secrete sebum, a waxy, oily material

•

inhibits growth of bacteria

•

lubricates and protects keratin of hair shaft, and conditions skin

•

absent on palms and soles Sebaceous follicles – not associated with hair. Discharge directly on to skin. On face, back, chest, nipples and male sex organs.

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Sweat Glands

•

also called sudoriferous glands

•

apocrine (merocrine secr.) glands associated with hair follicles thick, odorous secretion

•

eccrine (merocrine secr.) glands - most numerous - palms, soles, forehead, neck, back - directly on to surface - watery secretion - for thermoregulation Sweating with wetness = diaphoresis

•

ceruminous glands

•

mammary glands Specialized (apocrine secretion)

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Nails

(Perionychiu m) Hyponychium Know these terms Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007

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Regulation of Body Temperature

Hyperthermia – Abnormally high body temperature May be caused by - environment (heat, humidity) - illness ( fever [>=37.2

0 C], pyrexia ) - anesthesia (malignant h.) Corrected by loss of heat by radiation, convection, conduction, evaporation Heat exhaustion (prostration) - Fatigue - Dizziness - Headache - Muscle cramps - Nausea - May lead to heat stroke

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Regulation of Body Temperature

Hypothermia – Abnormally low body temperature (at least 2 0 C below normal body temp) May be caused by: - exposure to cold (primary) - illness (secondary) - surgical induction (clinical) Cardiac arrest is likely if temperature falls below 28 o C (82 o F) Corrected by mechanisms to retain body heat (see left)

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Healing of Cuts

Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 1. Bleeding/clotting 2. Scab formation Tissue repair can occur by either: 1) regeneration – 2) fibrosis – healing with tissue that was originally present healing with ‘scar’ tissue (carried out by fibroblasts)

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Healing of Cuts

3. Epidermal cell migration and collagen production 4. Shedding of scab; covering of wound with epithelium Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

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