Exam 3 Review Slides

Lectures 9-12Chapters 5, 6, and 7

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Types/Functions of Epithelial Tissue

• Functions of Epithelial Tissue– Physical protection– Control of permeability

• Secretion, Absorption, Filtration

– Provide sensation– Provide specialized secretions (glands)

• Types of epithelium• Covering and Lining Epithelium

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

• Glandular Epithelium

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Characteristics of Epithelial Tissue

• Specialized contacts with other cells

• Polarity (different ends of cell do different things)

• Avascularity (no blood supply)

• Regeneration (can divide to make new cells)

• Cellularity (lots of cells in close contact)

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

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Basal Lamina

Two components:

Lamina Lucida - glycoproteins and fine protein filaments - Barrier for passage of substances from underlying tissue into epithelium

Lamina Densa - bundles of coarse protein fibers - gives basal lamina its strength

Formerly called: Basement membrane

Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004

Lamina = thin layer

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Classification of Epithelial Tissues

• 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

Epithelial tissues are classified according to both their:

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Characteristics of Epithelial TissueSpecialized Contacts

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

Tight junction – forces substances to go through cells, rather than being able to pass between them

Gap junction – allow rapid passage of small molecules/ions between cells

Desmosome – binds cells together firmly so they stay connected

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Review

NAME OF ET DESCRIPTION STRUCTURE

LOCATION FUNCTION

SIMPLESQUAMOUS

a single layer of flattened cells

linings of air sacs, capillaries, lymph vessels, body cavities; covering ventral organs

diffusion, reduction of friction

SIMPLE CUBOIDAL

a single layer of cube-shaped cells with large centrally located nuclei

linings of kidney tubules, ducts of glands

absorption,secretion

SIMPLE COLUMNAR

a single layer of tall cells with basally located nuclei, goblet cells, & mucrovilli

lining of intestine protection,absorption,secretion

PSEUDO-STRATIFIEDCOLUMNAR

a single layer of tall cells with scattered nuclei, cilia, & goblet cells

lining of trachea,lining of fallopian tube

protection, secretion

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Review

NAME OF ET DESCRIPTION STRUCTURE

LOCATION FUNCTION

STRATIFIEDSQUAMOUS

many layers of flattened cells

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

protection

TRANSITIONAL several layers of cells that change shape under pressure

lining of urinary bladder and ureters

Distensibility (able to stretch)

GLANDULAR simple cuboidal lining the ducts of glands

secretion

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Review of Epithelial Tissues

• 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

• Glands are specialized epithelium

– Secrete on to a surface (exocrine)

– Secrete into a duct (exocrine)

– Secrete into the blood (endocrine)

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Membranes

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

Mucous• line tubes and organs that open to outside world• lining of mouth, nose, throat, digestive tract, etc.• secrete mucus

Cutaneous• covers body• skin

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.

Synovial• surround joint cavities

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ReviewNAME OF CT DESCRIPTION LOCATION FUNCTION

MESENCHYME Embryo gives rise to all other CT’s

AREOLAR gel-like matrix with fibroblasts, collagen and elastic fibers

beneath ET (serous membranes around organs & lining cavities)

diffusion, cushioning organs

ADIPOSE closely packed adipocytes with nuclei pushed to one side by fats

beneath skin, breasts, around kidneys & eyeballs

insulation, energy store, protection

RETICULAR network of reticular fibers in loose matrix

basement membranes,lymphatic organs

support

DENSEREGULAR

dense matrix of collagen fibers

tendons, ligaments attachment (high tensile strength)

DENSEIRREGULAR

loose matrix of collagen fibers

dermis of skin strength in several directions

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ReviewNAME OF CT DESCRIPTION LOCATION FUNCTION

ELASTIC CT matrix of elastic fibers

lung tissue, wall of aorta

durability with stretch

HYALINECARTILAGE

chondrocytes in lacunae in amorphous matrix

embryonic. skeleton, costal cart, tip of nose, trachea, larynx

support

FIBRO-CARTILAGE

less firm than above intervertebral discs, pubic symphysis

tensile strength, shock absorber

ELASTICCARTILAGE

above plus elastic fibers

external ear, epiglottis

shape maintenance plus flexibility

BONE concentric circles of calcified matrix

Bones support, protection, movement, Ca ++ storage, hematopoiesis

BLOOD red cells, white cells and platelets in liquid plasma

in heart and blood vessels

transport of nutrients, wastes & gases

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Name of CT

Different types of this CT

Main types of cells present

Main types of fibers present

Consistency of matrix Examples of Locations

CT Proper1) Areolar (Loose)2) Dense regular3) Dense irregular4) Adipose5) Reticular6) Elastic

1) Fibroblasts2) Fibroblasts3) Fibroblasts4) Adipocytes5) Fibroblasts6) Fibroblasts

1) Collagen, Elastic2) Collagen3) Collagen4) Reticular5) Reticular6) Elastic

Semi-liquid1) Skin, between muscles2) Tendons, ligaments3) Dermis 4) Body fat areas5) Stroma of liver, spleen6) Lungs, airways, arteries/heart

Cartilage 1) Hyaline2) Fibrocartilage3) Elastic

(All) Chondrocytes1) Collagen (sparse)2) Collagen (dense)3) Elastic

Semi-solid, gelatinous

1) Ribs, ends of bones2) Intervertebral disks3) Pinna of ear, epiglottis

Bone 1) Dense2) Spongy

(All) Osteocytes Collagen Solid (hydroxyapatite)

1) Outer portions of bone2) Inner portions of bone

Blood--

1) RBCs2) WBCs3) Platelets (cell fragments)

Fibrinogen (soluble) Liquid Blood vessels, heart

Lymph -- Lymphocytes Reticular (in stroma of lymphoid organs)

Liquid Lymph vessels

Connective Tissue (CT) Summary Table

Three main components of ALL CT: cell, fibers, ground substance

-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 cell• phagocytic• important in defense• derived from circulating monocytes

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Connective Tissue FibersCollagenous 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 collagenous fibers• highly branched• form supportive networks

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The “Ground Substance” of CT

Figures from: Alberts et al., Essential Cell Biology, Garland Press, 1998

VERY hydrophilic!

Very active in controlling passage of substances through this portion of the matrix and keeping CT hydratedGAGs = glycosaminoglycans (negatively charged

polysaccharides); a major molecule in ground substance

glucosamine

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Tendons and Ligaments

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

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CT Framework of the Body

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

Fascia connects the organs of the dorsal and ventral cavities with the rest of the body

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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Review of Muscle TypesNAME OFMUSCLETISSUE

DESCRIPTION OFSTRUCTURE

TYPE OFCONTROL

LOCATION FUNCTION

SKELETALMUSCLE

long, thin fibers with many nuclei and striations

Voluntary attached to bones to move bones

SMOOTHMUSCLE

spindle shaped cells with one centrally located nucleus, lacking striations

Involuntary walls of visceral hollow organs, irises of eyes, walls of blood vessels

to move substances through passageways (i.e. food, urine, semen),

constrict blood vessels, etc

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 heart pump blood to lungs and body

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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

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

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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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)

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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)

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

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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 (protection from UV radiation)

– Langerhans cells (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

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Skin Color

Genetic Factors• varying amounts and type of melanin• varying size/number of melanin granules• albinos lack melanin (but not melanocytes!)

Environmental Factors• sunlight• UV light from sunlamps • X rays

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)

• carotene -> Vit A (yellow)

• jaundice (yellow)

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Skin Color and Melanin

Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004

Melanocytes produce melanin

- tyrosine melanin - UV radiation up-regulates production of melanin - Caucasian vs. dark-skinned * number vs. activity * layer of epidermis

Dark-skinned Fair-skinned

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Keratin and Vitamin D

• Keratin– Protection

– Water resistance

• Vitamin D3 (“sunshine vitamin”)– After UV irradiation epidermal cells in s. spinosum and

s. basale convert a cholesterol-related steroid to Vit D3 (cholecalciferol)

– Vit D3 – absorption of calcium and phosphorus by small intestine

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DermisPapillary 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

- Stabilization of dermis

- Areolar and adipose tissue

- Effect of hormones- Reservoir of blood

Also called ‘hypodermis’. This is the superficial fascia.

- INSULATION

Basal lamina

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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

A hair in the scalp grows for 2-5 years, about 0.33mm/day

Nerves in root hair plexus

(from epidermis)

Basal lamina

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Hair Follicles

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

Some hair color

Types of hair:

1. Lanugo – long, blond, fine (fetal, anorexia nervosa)

2. Vellus – short, blond (children)

3. Terminal – course, pigmented (adults)

Hair color

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Sebaceous (Oil) Glands

• holocrine glands

• absent on palms and soles

• usually associated with hair follicles

• secrete sebum, a waxy, oily material

• inhibits growth of bacteria

• lubricates and protects keratin of hair shaft, and conditions skin 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

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

• ceruminous glands

• mammary glands

• also called sudoriferous glands

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

Specialized (apocrine secretion)

Sweating with wetness = diaphoresis

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Nails

Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007

Know these termsHyponychium

(Perionychium)

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Regulation of Body TemperatureHyperthermia – Abnormally high body temperature

May be caused by - environment (heat, humidity) - illness (fever [>=37.20C], 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 TemperatureHypothermia – Abnormally low body temperature (at least 20C 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 28oC (82oF)

Corrected by mechanisms to retain body heat (see left)

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

Healing of Cuts

Tissue repair can occur by either: 1) regeneration – healing with tissue that was originally present2) fibrosis – healing with ‘scar’ tissue (carried out by fibroblasts)

1. Bleeding/clotting

2. Scab formation

40Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

Healing of Cuts

3. Epidermal cell migration and collagen production

4. Shedding of scab; covering of wound with epithelium