Connective Tissue, Muscles, Nerve Tissue & Skin

Front 1

Support cells

Back 1

1. Fibroblasts

2. Myofibroblasts

3. Chondroblasts & chondrocytes

- make collagen II in cartilage

- Cartilage covers articular surfaces of bones

4. Osteoblasts & osteocytes

- make type I collagen in bone

5. Adipocytes

- white (unilocular) fat

- Brown (multilocular) fat

Front 2

Fibroblasts

Back 2

1. Principal cells that make collagen

- order collagen fibrils & fibers in ECM attaching it to fibroblast membranes

2. More resistant to injury

3. Crucial in response to injury

Front 3

Myofibroblasts

Back 3

1. Share many features with fibroblasts

2. Contain microfilaments & myosin thick filaments - add intrinsic ability of cell contraction

- critical in tissue reshaping after injury

Front 4

Permanent guest cells

Back 4

1. Macrophages

2. Mast cells

Front 5

Extracellular matrix

Back 5

1. Fibrillar proteins

- Collagen, elastin, fibrillin, fibronectin

2. Proteoglycans - form gel matrix with water

- long unbranched glycosaminoglycans linked to protein core

- GAG - highly (-) charged

3. Glycoproteins form structural proteins

- laminin - component of BM; binds integrins & links the cell membrane to basal lamina via entactin to collagen IV

- entactin

- tenascin

Front 6

Fibrillar proteins

Back 6

1. Derived from soluble precursors of support cells

2. Collagen - most abundant

Front 7

Type I collagen

Back 7

1. Skin, tendon, ligaments, bone, cornea

2. Most of the body's collagen

3. Replaces type III in wound healing

Front 8

Type II collagen

Back 8

Cartilage, intervertebral discs, and vitreous
body of the eye.

Front 9

Type III collagen

Back 9

1. Blood vessels, and reticular fibers in various organs and tissues.
2. Links the basal lamina of cells to underlying ECM in many tissues.
3. Comprises the main supporting fibers in the ECM surrounding the parenchymal cells of lymphoid

4. First to be synthesized in healing wound

Front 10

Type IV collagen

Back 10

Basal membrane

Front 11

Loose irregular connective tissue

Back 11

1. Submucosa

2. Papillary dermis

Front 12

Dense regular connective tissue

Back 12

1. Tendons
2. Bone
3. Cornea

Front 13

Dense irregular connective tissue

Back 13

1. Dermis
2. Capsules of organs

Front 14

Hyaline cartilage

Back 14

1. Forms a template for bone formation during embryogenesis,

2. Comprises articular cartilage on bone surface at synovial joints, cartilage of nose, portions of larynx, & cartilage of trachea & bronchi.

3. Rich in hyaluronic acid, chondroitin sulfate, and keratan sulfate.

4. High water content, and resists compression=> good shock absorber

Front 15

Elastic cartilage

Back 15

1. Contains elastic fibers & collagen II

2. Great flexibility

3. External ear, auditory canal, epiglottis of larynx

Front 16

Fibrocartilage

Back 16

1. Has collagen I & II=> great resistance to stretch (tensile strength)

2. Found in intervertebral disks, menisci, forms attachment of ligaments and tendons to bone.

3. Lacks perichondrium & has less water in ECM, compared to the other types of cartilage.

Front 17

Intramembranous bone formation

Back 17

1. Primitive mesenchyme gives rise directly to bone.

2. Flat bones of the skull during embryogenesis, dense cortical bone on the surface of bones.

3. Mechanism:

- Small collections of condensed mesenchymal cells induced to become osteoblasts.

- Collections grow & fuse into interconnected cords (trabecula) with intervening mesenchyme.

- This forms primary spongy bone, and has randomly arranged collagen fibers in its matrix.

4. Some trabeculae fuse to form dense cortical bone, w/o intervening large spaces filled with mesenchyme.

- Cortex gets remodeled to lamellar bone, forms outer surface of bones & doesn't have cavities for bone marrow & hematopoiesis.

5. Other trabeculae widen & form anastomosing network of trabeculae with intervening spaces

- have bone marrow, as intervening mesenchyme gets populated with hematopoietic cells.

- Trabecular/cancellous bone, comprises interior of most bones, whose outer surface is covered by cortical bone.
6. Flat bones of skull have 2 outer layers of cortical bone with intervening trabecular bone.

Front 18

Endochondral bone formation

Back 18

1. Bone is formed on the template of preexisting
hyaline cartilage formed from chondroblast & chondrocyte differentiation from chondroid progenitor cells derived from mesenchyme.

2. Long bones of extremities, vertebrae & pelvic bones

Front 19

Endochondral ossification

Back 19

Process of laying osteoid on the surface of preexisting cartilage

1. Primary center of ossification - shaft center (diaphysis) of cartilage template where initial ossification starts

- Progressive replacement of inner cartilage with
trabecular bone, which is laid down toward the ends of the bones=> increase in bone length.

2. Other osteoprogenitors at surface periosteum lay down osteoid as a layer on the outer surface of the cartilage template

- this form of intramembranous bone formation will ultimately form outer cortex of long bones.

3. Secondary (late) centers of ossification form

separately through cartilage hypertrophy

- Ingrowth of vessels from outside the cartilage template

- Replacement of cartilage by new trabecular bone and marrow.

- Takes place at ends (epiphyses) of long bones

4. Cartilage persists;

- bone ends forming joints

- interface of epiphysis with diaphysis - epiphyseal growth plate, important for bone elongation

Front 20

Astrocytes

Back 20

1. Most numerous glial cells in the CNS

2. Have large #s of radiating processes.

3. Provide structural support or scaffolding for CNS

4. Have large bundles of intermediate filaments that consist of glial fibrillary acidic protein (GFAP). 5. Uptake systems: remove glutamate and K from the extracellular space.

6. Have foot processes contributing to blood-brain barrier by forming a glial-limiting embrane. 7. Can hypertrophy and proliferate after an injury to the CNS

- fill up extracellular space left by degenerating neurons by forming an astroglial scar.

Front 21

Radial glia

Back 21

1. Precursors of astrocytes

2. Guide neuroblast migration during CNS development

Front 22

Microglia cells

Back 22

1. Smallest glial cells in the CNS.

2. Derived from bone marrow monocytes and enter the CNS after birth.

3. Link between cells of CNS and immune system.

4. Proliferate & migrate to the site of CNS injury & phagocytose neuronal debris after injury.
5. Pericytes - microglia that contribute to blood–brain barrier.

Front 23

Blood-brain barrier

Back 23

1. Consists of

- capillary endothelial cells & their tight junction - most important

- bsal lamina

- astrocytes

- pericytes

2.

Front 24

Layers of epidermis

Back 24

1. Stratum basale:

- proliferative basal layer (stem cells)

- columnar-like cells with keratin (keratinocytes)

- melanocytes (migrating neural crest cells)

2. Stratum spinosum:

- multilaminar layer of cuboidal-like cells

- keratinocytes bound together by #s desmosomal junctions

3. Stratum granulosum - sealing layer

- flat polygonal cells filled with basophilic keratohyalin granules.

- cells have #s membrane-coating granules.

4.Stratum lucidum - additional

- found only in areas of thick stratum corneum

- transiional zone of flat eosinophilic or pale-staining anucleated cells

5. Stratum corneum - superficial

- several layers of flat, inoculated & cornfield (keratinized) cells

Front 25

Eccrine sweat glands

Back 25

1. Size: 0.4 mm

2. Location: everywhere except penis

3. Site of opening: skin surface

4. Discharge: watery, little protein,

- mainly H2O, NaCl,

- urea, NH3, uric acid

5. Innervation:

- Cholinergic

Front 26

Apocrine sweat glands

Back 26

1. Size: 3-5 mm

2. Location: Axillary, areolar, anal

3. Site of opening: hair follicles

4. Discharge: viscous, odor producin

5. Innervation: adrenergic