Tissue Flashcards
Muscle Tissue
- striated appearance
- produce force = muscle actions (unique to muscle tissue)
- it’s all about the cells; not much intercellular material
Nervous Tissue
- carries and transfers information
- a lot of extracellular material, but it is NOT functional
Neuron
- cell of nervous tissue
Connective Tissue (CT)
- support, anchor, attach, and connect other tissues
- matrix gives CT its functional characteristic
4 Types of CT
1 - Fibrous
2 - Cartilage
3 - Bone
4 - Blood
All contain proteins: 1) collagen 2) elastic 3) reticular
Collagen
- type of CT fiber (Tri-Helical structure)
- well organized, mature fibers
- resist TENSILE forces (very little stretch)
- cannot resist compressive forces
- most abundant protein in the body
Tissues
- group of similar cells and intercellular substance which serve specific function
- intercellular = extracellular = matrix = ground substance
4 Types of Tissue
1 - Epithelial
2 - Muscle
3 - Nervous
4 - Connective
Epithelial Tissue
- lining of internal and external surfaces
- primarily cells (very little matrix)
- protects other tissues
- regulates movement into and out of other tissues
- i.e. lining -> get beat up andd must be replaced frequently.
Elastic Fibers
- develops tension and then returns to original shape (i.e. rubber band)
- made from elastin
- ability to stretch; it will yield
Reticular Fibers
- unorganized, immature collagen fibrils
- small fibers
- produced by FIBROBLAST
Loose Fibrous CT Subclasses
1 - Areolar
2 - Adipose
3 - Reticular
- Loose = not as many fibers
Dense Fibrous CT Subclasses
1 - Regular
2 - Irregular
3 - Elastic
- Dense = more fibers
Loose Fibrous CT
- most abundant CT
- mostly collagen
- filler tissue
- holds vessels and nerves
- poorly organized
- found in subcutaneous areas
(areolar, adipose, reticular)
Areolar Loose Fibrous CT
- gel-like matrix with all 3 fiber types
- wraps and cushions organs.
- cells are fibroblasts and macrophages
- found under epithelium of body
- as lamina propria (serves as the foundation for epithelial cells)
- surrounding capillaries and organs
Adipose Loose Fibrous CT
- cells = adipose cells (able to store large amounts of fat)
- very little intercellular space
- has matrix like areolar but it is very sparse
- fat pushes nuclei of cells to the side
- provides reserve food fuel
- supports and protects organs
- insulation against heat loss
- found under skin, in breasts, around kidneys and abdomen
Reticular Loose Fibrous CT
- found within bone marrow, spleen, and lymph nodes
- similar in appearance to areolar tissue
- network of reticular fibers in a loose ground substance
- fibers form a soft internal skeleton (stroma) to support cells (i.e. capillaries)
Dense Fibrous CT
- primarily collagen in various organized arrangements
regular, irregular, elastic
Regular Dense Fibrous CT
- named because of its ordered arrangement of parallel collagen fibers
- ideal at resisting tensile loads pulling in one direction
- major cell type is the fibroblast
- (i.e. tendons, ligaments, and aponeuroses)
Irregular Dense Fibrous CT
- collagen fibers have less ordered arrangement
- not as strong as REGULAR, but they can withstand loads in numerous directions
- (i.e. fibrous jt capsules, dermis of skin, and periosteum)
Elastic Dense Fibrous CT
- primarily consisting of elastic fibers (from elastin protein)
- (i.e. walls of arteries, trachea, and ligamentum nuchae [extension of supraspinous ligament])
Rank of Fiber Order Arrangement
Tendon > Ligament > Apon > Jt Capsule
(Most order Least order)
- all about the same density
Cartilage
- cells = chrondocytes
- gel matrix = proteoglycans
1 - hyaline cartilage
2 - fibrous cartilage
3 - elastic cartilage
Hyaline Cartilage
- strongest cartilage; best for compressional loading
- covering ends of bones; seen in articulations
- increased amount of gel substance
- ~40% collagen; 60% gel matrix
- (articular cartilage, embryonic precursor to bone, forms synchondroses)
Proteoglycans
- gel matrix in cartilage
- composes glycosaminoglycans (organic component of bone)
- affinity for water (good for cushion of loading)
Fibrous Cartilage
- increased amount of collagen fibers
- compression and tensile loading
- ~70% collagen; 10% elastin; 20% gel matix
- (fibrocartilage pads [i.e. menisci] and symphyses)
Elastic Cartilage
- mostly elastin
- not found in joints
- (epiglottis and outer ears)
Blood
- cells: erythrocytes, leukocytes, and thrombocytes
- platelets = cell remnants
- this “tissue” contains cells, and intercellular fluid matrix (plasma), and fibers (albumin)
- not typical CT because it doesn’t connect or support other tissues
Bone
- cells = osteoblasts, osteocytes, and osteoclasts
- composed of organic and inorganic materials
Organic Bone Components
- 30-35% dry wt
- cells
- collagen fibers (25-30% dry wt)
- glycosaminoglycans = gel substance (5% dry wt)
Inorganic Bone Components
- 65-70% dry wt
- mineral salts
- hydroxyapatite crystals
- Ca10(PO4)6(OH)2
3 Types of Muscle Tissue
1 - Smooth
2 - Skeletal
3 - Cardiac
Mesenchyme
- common embryonic origin for all 4 types of CT
- undifferentiated cells at this point
- essentially like stem cells
- progress into their specific type of cell b/c of chemicals in environment and the mechanical loading they undergo
Organ
- 2 or more tissues working cooperatively to perform a specific function
- (i.e. heart (CV system)
stomach (digestive system)
Organ System
- group of organs and tissues functioning cooperatively to perform specific functions.
5 Competing Functions of Skeletal System
1 - Structure/support 2 - Protection 3 - Movement 4 - Calcium storehouse 5 - Blood cell production
These functions can be in conflict with each other.
Long Bones
- found in UE and LE
Flat Bones
- ribs
- sternum
Short Bones
- carpals and tarsals
Irregular Bones
- pelvis
- hyoid
- scapula
Sesamoid Bone
- patella
Periosteum
- outside covering of bone
- contains periosteal vessels (small, but abundant) for blood supply
- Dense Irregular Fibrous CT
- osteoblasts found just deep to periosteum.
Endosteum
- lining medullary cavity and within pores of trabecular bone
- Dense Irregular Fibrous CT
Compact vs. Spongy Bone Locations
LONG BONES:
- compact found in diaphysis and covering surface of epiphysis - trabecular found in epiphysis
ALL OTHER BONES
- trabeular found throughout bone - compact bone covering surface of entire bone
Nutrient Arteries
- one or two large arteries
- pass through nutrient foramen
Epiphyseal Vessels
- network of vessels interwoven throughout plates/rods of trabecular bone
Osteoblast
- deposition (growth, repair, and remodeling)
- produce organic components of bone (collagen and gel)
- found on surface of bones (deep to periosteum) and within trabecula
Osteoclast
- resorption (unloading, repair, remodeling)
- multinucleated, much bigger than osteoblasts
- chew up all substances of bone, and spit it back out
- Therefore, they do not change the composition of bone, just the amount of bone.
Osteocyte
- mature osteoblast (occurs once osteoblast has produced a matrix and becomes mineralized)
- both produce and resorb bone, but do neither as effectively as osteoblast or osteoclast.
- There job is maintenance, focusing on microdamage.
Ideal Matrix Composition
1 - Type 1 Collagen (25-30%)
2 - GAG [glycosaminoglycans/gel] (5%)
3 - Hydroxyapatite [mineral] (65-70%)
Diet Factors Affecting Bone Composition
Protein And Vitamin C
- need both protein and vitamin C to produce collagen.
- not enough collagen will cause shift to more brittle bones
- great increase in fractures (think pirates & scurvy)
Diet Factors Affecting Bone Composition
Calcium and Vitamin D
- lack of calcium and/or ability to absorb calcium (vitamin D)
- results in decreased mineral content of bones (bones too compliant)
- results in bone softening (rickets/osteomalacia)
Bone Response to New Exercise Program
- after initial increase in activity level, both osteoblasts and osteoclasts get busy
- results in losing bone at first
- over time with continued exercise osteoblasts catch up, resulting in gaining bone and it becomes stronger.
