1. Epithelial Tissue

2. Connective Tissue

3. Muscle Tissue

4. Nervous Tissue

1. Protection

2. Act as a permeable membrane

3. Secretion

4. Absorbtion

5. Contractility

6. Sensation

The basal lamina is a sheet-like extracellular structure at the base of epithelial tissue. Can be on or multiple layers and can only be seen through an electron microscope.

Its two layers include the lamina dense and lamina lucida

1. Membranes

2. Glands

AKA endothelium

- One layer of flat epithelial cells, loosely held together, that are designed to aid in absorption

- Muliple layers of flat squamous epithelial cells siiting on a basement membrane. Beneficial for protection. Can be keratinized or non-keratinized.

Square shaped epithelial cells one layer deep sitting on a basement membrane.

Ex. Kidney collecting tubules

Multiple layers of cuboidal cells on a basement membrane

Ex. Sweat glands

Appears to be stratafied, but is not.

- Can be cilliated or non-cilliated

When distended cells are squamous and can relax and cells appear cuboidal.

Ex. Bladder

1. Shape

2. Branches

3. Nature of secretion

4. Method of secretion

5. Number of cells

1. Simple Alveolar

2. Simple Tubular

3. Coiled Tubular

1. Tubular

2. Alveolar

3. Tubuloalveolar

1. Uni-cellular (only goblet cell)

2. Multi-cellular

1. Halocrine - Cell disintergrates to release contents

Ex. Sebacceous cell

2. Apocrine - A small amount of cytoplasm is released with secretory capsule

Ex. mammory gland

3. Merocrine - Most common - Secretion is discharged by fusion of the membranes. Only contents is discharged

Ex. Mucous gland

1. Serous

2. Mucous

3. Mixed

1. Occuludens - Very close junction, or closed almost completely

2. Adherens - Has a small space between cells - 20 nm

3. Gap junction - Have a tight junction, but has pores that allow certain substances to cross

1. Resist mechanical forces trying to seperate cells

2. Passage of substances

3. Hold cells together

They are made by the same substances, but

1. The adhesion betweet CT is not as stong

2. CT has less fluids and more fibers

1. Provide and maintain the form of the body

2. Provide a medium for supplying nutrients to the body

3. protection

4. Assist and limit movements

5. Connects and bind the organs and cells that give support to the body

1. Loose areolar

2. Dense (regular and irregular)

3. Elastic

4. Reticular

5. Adipose

An abundant tissue that fills spaces between fibers and muscle sheaths, supprts epithelial cells, and surrounds lymphatic and blood vessels.

- Does not contain a lot of collagen fiber, more cells that take up space

- It is flexible, well vasularized stretchable

Consist of similar substances at loose CT, but has an increased number of collagen fibers and fewer cells

- A far more resistant type of tissue

- Two types - regular and irregular

- Collagen fibers are arranged in bundles without a diffinite orientation, providing resistance in all directions.

Ex. Fascia

1. Superficial

2. Deep

3. Subserous

Fiber are aranged according to a deffinite pattern in reponse to prolonged stress in a certai direction.

- Offer great resistance to tractional forces

Ex. Tendons, ligaments, aponeurosis

The presense of elastic fibers that allows a slight stretch.

Ex. Flavum ligament of the vertebral column

- Occurs infrequently

- Space b/w fibers is occupied by collagen fibers

- Wel-like and acts like a filter especially in the spleen and lymph nodes

- Provides a framework for bone marrow

- Monitors flow of materials through sinus

- Formed from CT, reticular fiebrs and reticular cells

-Fat cells that are scattered though out areolar CT

- They are rich in blood supply and require a large metabolic activity

- usually develope in subcutaneous tissue

-Fully differentiated

1. Shock absorber

2. Energy store

3. Insulator

1. Cartilage

2. Blood

3. Bone

1. Cells  - (chondroblast/cytes) - 10%

2. Collagen type 2 - 20 - 30%

3. others...

1. Hyaline - most abundant

2. Elastic - more pliable

3. Fibro - Resist great stress

1. Avascular - get nutrients by diffusion

2. Low metabolic activity

3. Poor regenration

4. No lymphatics or innervation

- Dense irregular CT

Has a fibrous layer (collagen and fibroblast) and chondrgenic layer (chrondogenic cells and chrondoblast)

- Not on articulating surface

Located where more flexibility is requred becuase the matrix contains an elastic component/fibers

Ex. auditory tube, epiglotis

- Located wehre tough support or tensile strength is needed

- Has smaller chondrocytes arranged in parallel rows b/w bundles of thick collagen fibers

Ex. Vertebrae, SC joint, TMJ

1. Appositional

2. Interstitial

- The formation of cartilage onto the surface of pre-existing cartilage

            - Cells are derived from the Perichondrium

- Results from mitotic division of pre-existing chondrocytes within the cartilage     mass

            - Less important of the two, occurs only in early phases of cartilage formation       

1. Cells

2. Plasma

3. Cell fragments

- Transport O2 and Co2

- Have a clear center becuase they have no nucleus

1. Basophil

2. Lymphocyte

3. Esinophil

4. Neutrophil

5. Monocyte

20-40%

Produces Antibodies

Small

Single, large, eccentric nucleus

Agranular

1-2%

Large graules

Sausage shaped nucleus

Pagacytosis of antigene-antibody complex

Nucleus has 2 connected lobes

50-70%

Phagacytosis

Granular

Multi-lobed nucleus (connected)

2-8%

Largest

Phagocytosis

Large, eccentric, kidney shaped nucleus

Agrannular

<1%

Large S-shaped nuceus

Dense, dark, large granules

Contains histamine and heparin that are involved in allergic rx

Cell frangments

AKA platelets

Important for clogging

250-500 K per cubic mm

1. Protection

2. Support

3. Movement

4. Blood formation

5. Salt store (Ca, Mg, Phosphorus

1. Spongy or cancellous

2. Hard or compact

Consist of a lamalae structure that are arranged determined by blood vessels

1. Long
2. Short
3. Flat – Two plates of hard bone sandwiching spongy bone (diploe)

      - This occurs in the skull, and also the sternum and scapula have flat bones

D. Irregular – various shapes, for example the vertebral disc and fascial muscles

E. Pneumatic – Contains air. Ex. temporal bone

F. Sesamoid – Round or oval and lying within a tendon, Ex. pisiform

G. Accessory – Develop after additional ossification occurs

  1. Cells

2. Intercellular Matrix

1. Osteoblast - bone formation cells located on the surface of bone

2. Osteocytes - Bone cells located within the lacunae

3. Osteoclast - Multi-nucleated, giant cells foudn close to the surface and function in bone reabsorption

A. organic materials

35% of weight

mostly collagenous fibers

b. Inorganic materials

65% of weight

Fibrous CT membrane covering bone, except at the articulations.

- Serves as a supportive structure for blood vessels, nerves, and attachments of tendons and ligaments

1. Outter layer - finrous later

2. Inner layer - Cell rich layer containing osteoblast

Similar to periosteum, but bot as developed.

- Lines the marrow cavities and marrow spaces

1. Intramembraneous

2. Endochondrial

Bone forms on or w/i a membrane by direct mineralization of matrix secreted by osteoblast

- Flat bones and thickening of long bones

- This is how bone originally starts off

Developes w/i cartilage by deposition of bone matrix on pre-existing cartilage matrix

- Primary short and long bones

bone that is formed prior to any remodeling

- no lamallae structure

- Wooven bone AKA

- Forms more rapidly, but not very dynamic

1. Fibroblast

2. Adipose

3. Ground substances

4. Tissue fluid

5. Fibers (collagen, reticular, elastic

•         most abundant (90%)

•          located in dermis, bone, tendon, fascias, fibrocartilage and organ capsules

•          densely packed thick fibrils

•          resists tension, forces and stretch

•         present mainly in hyaline and elastic cartilage

•          thin fibers formed only, loose fiber network

•          resistance to intermittent pressures

•          provides shape and resistance to deformation

•           major component in reticular fibers

•          located in smooth ms, arteries, uterus, liver, spleen, lung, CT of organs, fetal skin.

•          Loose network of thin fibers

•          maintains integrity in structures that can expand

•          therefore, provides structural support and elasticity

•          located in the basal lamina of epithelium, endothelium, kidney

•          does not form fibrils or fibers

•          support and filtration

•           soft, flexible, relatively inelastic and high tensile strength

•         fibers aggregated in parallel and form collagen bundles

•           consist of closely packed thick fibrils with an average diameter of 75 nm

• Makes up the ultrastructure of collagen

•          protein unit that polymerizes to form collagen fibrils

•          280 - 300 nm long

•          1.5 nm width

•          consists of 3 subunits polypeptide chains intertwined into a triple helix (diagram)

•          differences in the chemical structure of these chains cause the different types of collagen

•         fibrils are striated - due to the overlapping arrangement of the subunit tropocollagen (diagram)

•          A collagen fiber of 1 mm diameter can support a mass of at least10 kg before it breaks

1. Parallel (abdominals)

2. Pennate(deltoids)

3. Convergant (biceps)

              - Long excursions                                                     

- Good endurance

            - Not overly strong                                         

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            - Ex. Erector spinae

Fan-shaped

Maximizes contraction

Feather like with good dexterity

            - Short excursions

            - Very strong but tires quickly

            - Increased pennates = increased strength

            - Ex. anterior tib, soleus, deltoid

A collection of sacromeres lines in a series

- A bundle of myofilaments

Conducts the depolarization down the muscle.

            - A tubular system that forms a sheet around each myofibril and is filled with calcium

- Vary from 1-40 nm in length and 10-60 microns in diameter

- Multinucleated

- Sarcolema – Membrane surrounding each fiber

A protein that wraps around the actin

•         Probably acts as inextensible template for thin filament assembly

•         anchors the terminal actin filaments in the myofibril to the membrane

•         important in transmitting tension from the myofibrils to extracellurlar matrix

•         Large protein

•         Abundant: 3% to 4% of myofibrillar protein

•         Extends whole length of thin filament

•         2 nebulin molecules per thin filament

Wraps around the myosin and helps to anchor it to the Z disk

- Has a wrinked structure, acting in an elastic fiber

- Involuntary muscle that is non-striated and has a single nucleus.

- each fiber contracts on its own

- Has intercalted disk to allow the heart to function as one big muscle and contract together

- Involuntary

- non-striated

- Single, centraly located nucleus

- No T-tubules

Poorly developed SR

Visceral - many gap junctions, electrically coupled, sheets of fiber contract

Multiunit - Few gap junctions and contract individually

Keratinocytes = make cells keratinized

Melanoctyes = produce melanin (protect skin from sun)

Langerhans cells = immune response

Merkel cell = basale layer - mechanoreceptor

- Heaviest organ in the body, about 16% of body weight

- .4-4 mm in thickness

Epidermis - stratified squamous keratinized epithelium derived from ectoderm

Dermis – vascular dense irregular collagenous CT w/elastic tissue – mesoderm

Subcutaneous Tissue – loose CT (not really part of skin); superficial fascia layer; adipose and areolar in character

1. Prevents water loss

1. Receptor – communication w/environment (cutaneous nerve receptors)

1. Protection from impact/friction injuries, sun (melanin=pigment in skin)

1. Thermoregulation

1. Highly resistant to abrasion/infection

1. Forms Vitamin D from sunlight

1. Body metabolism/excretion of substances by glands

•         protective barrier to phys, chem. and biological intrusions

•         maintains homeostasis (temp and water)

•         sensory receptor in cutaneous nerves

•         Secretory (produces Vitamin D)

•         Excretory (through sweat glands)

•         Produces melanin to protect from UV rays

•         No vessels

•         Derivatives hair, nails, sebaceous and sweat glands

1. Stratum basale

2. Stratum Spinosum

3. Stratum Granulosum

4. Stratum Lucidum

5. Stratum Corneum

1 layer columnar/cuboidal cells resting on basal lamina at dermal epidermis junction

Lots of desmosomes bind cells together

Lots of cell division (renewed every 15-30 days)

Separates dermis from epidermis

Includes Merkel cells and melanocytes

1. many layers of irregular polyhedral cells
2. Cuboidal, polygonal or flattened cells (squished together bc they’re closer to the surface)
3. Cells bond together by filament filled cytoplasmic spines and desmosomes (give cell prickle-studded appearance)
4. Keeps cells together
5. Protects from abrasions
6. Maintains cohesion among cells/resists abrasion
7. Skin subject to friction needs a thicker layer (ex - soles of feet)

1. -5 layers of flatten polygonal cells w/central nuclei
2. Contain keratohyalin granules w/protein that bind keratin filaments
3. Makes keratin
4. Coats granules in extracellular matrix to make it more waterproof
5. Layers act as barrier to penetration by foreign materials
6. Provides sealing effect in skin

1. clear layer 3-5 layers thick
2. More apparent in thick skin (not all species have it)
3. Translucent, thin, non-nucleated, flattened (dead cells)
4. 1^st layer where cells are dead (we start to lose them)

1. clear, dead, scale-like cells – 15-20 layers
2. Flattened, non-nucleated, keratinized filaments
3. Makes skin impermeable
4. Protects from outside objects getting into body
5. Thicker skin=higher resistance/permeability
6. Cells are continuously shed at surface
7. Most important layer bc it faces the surface

- CT supports epidermis – binds epidermis to subcutaneous tissue

- Variable thickness depending on body location

-  contain sweat glands, hair follicles, nerves, blood and lymph vessels

1. Papilary PD

2. Reticuldar RD

1. loose CT and fibroblasts; binds epidermis to dermis
2. Vascular network that supplies avascular epidermis with nutrients
3. network for thermoregulation (vasculature from dermal papillae)
4. contains free sensory nerve endings/structures in highly sensitive areas called Meissner’s corpuscles
5. consists of dense irregular CT

• thicker cells of irregular CT (>fibers, <cells)
• Loose CT
• Gives skin strength and elasticity
• Houses other epithelial structures like glands and hair follicles

- Not part of skin - superficial fascia and fat (unilocular adipocytes)

- Loose CT attaches skin to subjacent organs/tissues

- Loose flexible attachment (skin can slide over organs)

• long keratinized structure made of specialized keratinocytes
• Don’t grow continuously (cyclic growth)
• Growth affected by androgens, adrenal/thyroid glands hormones
• Grows from follicles

1. plates of keratinized epidermal cells on dorsal surface of each digit
2. Epidermal fold cover root
3. Stratum corneum forms eponychium – cuticle
4. Growth – nail matrix cells divide and move distally and cornify forming proximal nail plate to slide over nail bed

• attaches to glassy membrane/papillary layer of dermis -  contraction causes “goosebumps”
• Hair color produced by melanocytes at root of follicle near dermal papilla
• Melanocytes produce pigment that’s passed to cells of medualla and cortex