ANATOMY OF THE EYE

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Your eye is a slightly asymmetrical globe, about an inch in diameter. The front part (what you see in the mirror) includes:
  • Iris: the colored part
  • Cornea: a clear dome over the iris
  • Pupil: the black circular opening in the iris that lets light in
  • Sclera: the white of your eye
  • Conjunctiva: a thin layer of tissue that covers the entire front of your eye, except for the cornea
Just behind the iris and pupil lies the lens, which helps focus light on the back of your eye. Most of the eye is filled with a clear gel called the vitreous. Light projects through your pupil and lens to the back of the eye. The inside lining of the eye is covered by special light-sensing cells that are collectively called the retina. It converts light into electrical impulses. Behind the eye, your optic nerve carries these impulses to the brain. The macula is a small extra-sensitive area in the retina that gives you central vision.

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HUMAN EMBRYOGENESIS (STEP 1-4)

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CENTRAL NERVOUS SYSTEM

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ANATOMY OF THE KNEE

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The knee is one of the largest and most complex joints in the body. The knee joins the thigh bone (femur) to the shin bone (tibia). The smaller bone that runs alongside the tibia (fibula) and the kneecap (patella) are the other bones that make the knee joint. Tendons connect the knee bones to the leg muscles that move the knee joint. Ligaments join the knee bones and provide stability to the knee: The anterior cruciate ligament prevents the femur from sliding backward on the tibia (or the tibia sliding forward on the femur). The posterior cruciate ligament prevents the femur from sliding forward on the tibia (or the tibia from sliding backward on the femur). The medial and lateral collateral ligaments prevent the femur from sliding side to side. Two C-shaped pieces of cartilage called the medial and lateral menisci act as shock absorbers between the femur and tibia. Numerous bursae, or fluid-filled sacs, help the knee move smoothly.
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SKELETAL SYSTEM (TYPES OF BONES AND PARTS)

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The skeletal system includes all of the bones and joints in the body. Each bone is a complex living organ that is made up of many cells, protein fibers, and minerals. The skeleton acts as a scaffold by providing support and protection for the soft tissues that make up the rest of the body. The skeletal system also provides attachment points for muscles to allow movements at the joints. New blood cells are produced by the red bone marrow inside of our bones. Bones act as the body’s warehouse for  calcium, iron, and energy in the form of fat. Finally, the skeleton grows throughout childhood and provides a framework for the rest of the body to grow along with it. Skeletal System Anatomy The skeletal system in an adult body is made up of 206 individual bones. These bones are arranged into two major divisions: the  axial skeleton  and the  appendicular skeleton .   Types of Bones All of the bones of the body can be broken down into five types: long, short, flat, irregular, and
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