Sunday, March 28, 2021

TYPES OF JOINTS IN THE HUMAN BODY

Joints occur at regions where two bones meet. They are classified as

  • Immovable joints: Also known as fixed joints.  There is relatively no movement between the bones. There is no cartilage between the joints. Examples: Bones of the cranium and facial bones that articulate with the teeth
  • Movable joints: Also known as synovial joints. The bones of this joints are capable of movements. The bones are separated by cartilage called articular cartilage. The movement may be partial or freely moveable.
  • Partially moveable joints: Very limited range of movement.            Example: The joint between the vertebrae; The joints of the cranium; The joints of the hip bones.
  • Freely moveable joints: There are free movements between the articulating bones. The articular surfaces are covered with cartilage. This articular cartilage reduces the friction between the two surfaces of bones making the joint. It is covered by a synovial membrane which forms a closed sac. This sac contains a fluid called synovial fluid. The synovial fluid helps in lubricating the joint to reduce friction. 
Types of freely moveable joints 

Classification is based on the degree of movement that they allow. 

  • Hinge joints: These joints allow the backward and forward movement in only one plane. Examples: Elbow and knee joints
  • Ball and Socket joints: These joints allow movements in multiple planes. Examples: Shoulder and hip joints
  • Pivot joints:  Only rotational movements are possible in these joints. Examples: The joint between the first and second cervical (neck) bones.

 

Thursday, March 25, 2021

DATA ANALYSIS TYPE OF QUESTIONS

 In the given hypothetical reaction: A+BAB, the reactants A and B are consumed while the concentration of product AB increases.  The reaction rate can be determined by measuring how fast the concentration of A or B decreases, or by how fast the concentration of AB increases.  The graph below shows a reaction profile in which the reactants (red) decrease in concentration as the products increase in concentration (blue).


RateWiki (1).jpg

Answer the following questions based on the information above.

1. At what time is the reaction in equilibrium?
    A. 6 s
    B. 10 s
    C. 8 s
    D. 9 s

2. What is the concentration of the product at equilibrium?
    A. 0.3 M
    B. 0.4 M
    C. 0.45 M
    D. 0.5 M

3. During which time interval is the rate of the forward reaction greater than the rate of reverse reaction?
    A. 0-9 s
    B. 9-10 s
    C. 10-15 s
    D. 15-25 s

4. During which time interval is the rate of the reverse reaction greater than the rate of the forward  reaction?
    A. 0-9 s
    B. 9-25 s
    C. 5-9 s
    D. 0-5 s

5. What is the concentration of the product at the beginning of the reaction?
    A. 1.0 M
    B. 0 M
    C. 1.15 M
    D. 0.5 M

6. What is the concentration of the reactants at the beginning of the reaction?
    A. 1.0 M
    B. 0 M
    C. 1.15 M
    D. 0.5 M


ANWSERS
1. D          2. C           3. A         4. B           5. B          6. C

THE ANATOMY OF THE TEETH

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