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Movement is an important feature of a living organism. Both the microbes and microbes show a wide range of movements. The movements result in a change in location is called locomotion. At a cellular level, cytoplasm exhibits streaming movements. Movements of cilia, flagella etc bring locomotion. Locomotion is a very important feature of animals. It helps them to go in search of food, shelter, mate etc.
Types of movements:Human body exhibit three types of movements:
- Amoeboid movement: This movement is brought by pseudopodia, eg: macrophage and leucocytes move with the help of pseudopodia and engulf pathogens.
- Ciliary movement: Most of our internal tubular organs are lined by ciliated epithelium. Those which are present in trachea help in removing dust particles. In spinal canal they help in movement of cerebrospinal fluid.
- Muscular movement: The muscular tissue help in movement and locomotion. e.g., eye lids, tongue, limbs, blood within blood vessel and heart etc. This movement requires coordination between muscular, skeletal and nervous activities. Muscles are mesodermal in origin. Based on their structure they are classified as skeletal
HUMAN SKELETAL SYSTEMThe protective and supportive structure of the human body is called the skeletal system. They are of two types based on location:
- Exo-skeleton: – It is a protective and supportive structure present on the surface of the body. e.g., Hair and nails. (In other animals, carapace, shell, scales, shield, fur, hoof, horn, claws etc.)
- Endo-skeleton:- It is present inside the body. It is cartilage, bone or both.
- It provides frame work to the body and provides definite shape.
- It protects vital and delicate organs like the brain, lungs, heart, etc..
- It provides a site for the attachment for the muscles.
- It helps in the movement and locomotion.
- It is a hemopoietic organ(red bone marrow produces corpuscles).
- It stores fat(yellow bone marrow).
- It is a reservoir of mineral salts.
- Axial Skeleton: It is in the median longitudinal axis of the body which includes skull, vertebral column, sternum and ribs. It has 80 bones.
- Appendicular skeleton: It is present on the lateral side of the axial skeleton. It has 126 bones.
JOINTS:Joints are the places of articulation between two or more bones or between bone and cartilage. A joint is also known as articulation. Based on mobility there are 3 types of joints.
- Fixed joints or Immovable joints: These are the joints in which the bones are well joined or well sutured. Hence there is no space between them and they do not move. (It is like two tin or iron sheet welded together) Eg: – Skull bones.
- Slightly movable joints: They are also called cartilaginous joints. Between the bones, there is a very little space filled by cartilage. Such a joint is called symphysis. For eg:- Pubic symphysis, intervertebral disc, etc. It is because of this kind of joint we can bend and rotate our backbone to some extent.
- Freely movable joints or Synovial joints: These kinds of joints allow the movement of articulation. It is free because there is synovial cavity between the bones. This cavity is lined by a synovial fibrous membrane which contains secretory cells and secretes thick jelly-like fluid. The fluid not only acts as a lubricant but also provides nutrients to the joint and helps to maintain the stability of the joints. It reduces friction. There are of various types of synovial joints: a) Ball & socket joint. Eg:- Hip joints, shoulder joints. b) Pivot joint. Eg:- Radio & ulna below the elbow. c) Hinge joint. Eg:- Elbow, knee joints. d) Sliding joint. Eg:- Between carpal bones and between tarsal bones. e) Condyloid joint. Eg:- Metacarpals and phalanges. f) Saddle joint. Eg:- Carpals and metacarpals of thumb.