BIO-GEO CHEMICAL CYCLE OR NUTRIENT CYCLE Bio - Living organism Geo - Rock, Soil, Air, Water Chemical - Material or Nutrients Cycle - Path All the types of material required by ecosystem in addition of energy, are available continuously to system through recycling. Thus there is a constant exchange of materials between the living organism and their abiotic environment through the recyling of materials. This phenomenon is called Bio-geo chemical cycle. Note: Environment factors,e.g soil , moisture, ph, temperature etc, regulate the release of nutrients into the atmosphere. Biochemical cycle The following types of cycle are found in an ecosystem. (i) Gaseous Cycle - C, H, N. O cycles. Reservoir is in the atmosphere (air) or in Hydrosphere(water). Sedimentary cycle - P. S, Ca cycles reservoirs are in earth's crust (lithosphere). Note : In these cycles, the bulk material remains in the inactive reservoir on earth crust like sediment of sea, or water
CARTILAGE
Outer most covering of cartilage is called Perichondrium which is composed of white fibres connective tissue.
Cartilage producing cells are arranged on periphery of cartilage known as Chondrioblast.
These are active cell & divide to f
orm chondriocytes, and synthesize the matrix of cartilage.
Mature cells of cartilage is called Chondriocytes.
They are found in vacuole like space in matrix called Lacuna. In which 1 - 4 Chontrocytes are present.
Chondrioclast are cartilage destroying cells.
Matrix of cartilage is called chondrin composed of chondromucoprotein having Chondrotin-6-sulphate
and mucopolysacchride (Hyaluronic acid)
Matrix of cartilage provides rigidity & elasticity to cartilage. (Matrix solid, Pliable and resists compression)
Blood circulation is absent in the matrix of cartilage but blood supply present in perichondrium.
Type of Cartilage — There are following types of cartilage
1. Hyaline Cartilage.
2. Fibrous Cartilage (a) Elastic cartilage (b) White fibrous cartilage
3. Calcified Cartilage.
1. Hyaline cartilage
It is maximum in human body.
Most of the part of embryonic skeleton is composed of this cartilage. So maximum bones of body are cartilagenous bones because they are developed from cartilage.
Outermost covering perichondirum is present.
Matrix of this cartilage is glass like clear or hyaline matrix because libres are completely absent in the matrix of this cartilage. Only few collagen fibres may be present.
Colour of matrix is bluish & it is translucent/glass like.
eg. (a) Nasal septum.
(b) 'C' shaped rings of trachea and bronchi. (Incomplete in dorsal surface)
(c) Sternal part of ribs (Coastal cartilage)
(d) Larynx
Articular cartilage :- All the junction of two long bones on articular surface. At the end of long
bone perlosteum is absent and Ilyaline cartilage is present known as articular cartilage.
2. Fibrous cartilage
(A) Elastic cartilage
In the matrix of this cartilage yellow fibres form network so it is highly flexible cartilage of body
Colour of matrix is pale yellow
Eg. a. Tip of Nose
b. Ear Pinna (Outer ear joint)
c. Epiglottis
d. Wall of eustachian tube
(B) White fibrous cartilage
Perichondrium is absent (only in WF cartilage) because complete WFCT is converted into cartilage.
In matrix bundle of collagen libres are more in quantity soil is strongest cartilage.
E.g. Pubic symphysis
Pubis bone (half part of pelvic girdle Osinnomineta) are interconnected by pubic symphysis.
Intervertebral disc
A pad of cushion like structure which absorb mechanical shock & jerks and protect vertebral column
Central part of this disc is soft called as Nucleus pulposus,
Slight elongation of body after death or in sleeping posture is due to relaxation of this disc.
3. Calcified cartilage
It is modified hyaline cartilage but due to deposition of calcium salts its matrix becomes hard like bones.
It is hardest cartilage of the body.
Ca salt deposits in the form of Hydroxy apatite Ca¹⁰(PO⁴)⁶(OH)²,
Eg.
Pubis of frog's pelvic girdle.
Supra scapula of pectoral girdle of frog.
Head of femur & humerus in man.
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