UNIT I - BONES AND MUSCLE PHYSIOLOGY
A bone is a rigid organ that constitutes part of the vertebral skeleton. Bones support and protect
the various organs of the body, produce red and white blood cells, store minerals and also enable
mobility as well as support for the body. Bone tissue is a type of dense connective tissue.
TYPES OF BONES
There are 5 types of bones in the human body. These are long bones, short bones, flat bones,
irregular bones and sesmoid bones.
Long Bones
Long bones are some of the longest bones in the body, such as the Femur, Humerus and Tibia
but are also some of the smallest including the Metacarpals, Metatarsals and Phalanges.
The classification of a long bone includes having a body which is longer than it is wide, with
growth plates (epiphysis) at either end, having a hard outer surface of compact bone and a
spongy inner known an cancellous bone containing bone marrow. Both ends of the bone are
covered in hyaline cartilage to help protect the bone and aid shock absorbtion.
2
,Short bones are defined as being approximately as wide as they are long and have a primary
function of providing support and stability with little movement. Examples of short bones are the
Carpals and Tarsals - the wrist and foot bones. They consist of only a thin layer of compact, hard
bone with cancellous bone on the inside along with relatively large amounts of bone marrow.
Flat bones are as they sound, strong, flat plates of bone with the main function of providing
protection to the bodies vital organs and being a base for muscular attachment. The classic
example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium
(skull), os coxae (hip bone) Pelvis and Ribs are also classified as flat bones. Anterior and
posterior surfaces are formed of compact bone to provide strength for protection with the centre
consisiting of cancellous (spongy) bone and varying amounts of bone marrow. In adults, the
highest number of red blood cells are formed in flat bones.
These are bones in the body which do not fall into any other category, due to their non-uniform
shape. Good examples of these are the Vertebrae, Sacrum and Mandible (lower jaw). They
primarily consist of cancellous bone, with a thin outer layer of compact bone.
Sesamoid bones are usually short or irregular bones, embedded in a tendon. The most obvious
example of this is the Patella (knee cap) which sits within the Patella or Quadriceps tendon.
Other sesamoid bones are the Pisiform (smallest of the Carpals) and the two small bones at the
base of the 1st Metatarsal. Sesamoid bones are usually present in a tendon where it passes over a
joint which serves to protect the tendon.
The human skeleton consists of 206 bones and 32 teeth. The human skeleton also includes
ligaments and cartilage. Ligaments are bands of dense and fibrous connective tissue that are key
to the function of joints. Cartilage is more flexible than bone but stiffer than muscle. Cartilage
3
,helps give structure to the larynx and nose. It is also found between the vertebrae and at the ends
of bones like the femur.
4
, The bones provide structure and protection and facilitate motion. Bones articulate to form
structures. The skull protects the brain and gives shape to the face. The thoracic cage surrounds
the heart and lungs. The vertebral column, commonly called the spine, is formed by over 30
small bones. Then there are the limbs (upper and lower) and the girdles that attach the four limbs
to the vertebral column.
Bones of the human skeletal system are categorized by their shape and function into five types.
The femur is an example of a long bone. The frontal bone is a flat bone. The patella, also called
the knee cap, is a sesamoid bone. Carpals (in the hand) and tarsals (in the feet) are examples of
short bones.
5
A bone is a rigid organ that constitutes part of the vertebral skeleton. Bones support and protect
the various organs of the body, produce red and white blood cells, store minerals and also enable
mobility as well as support for the body. Bone tissue is a type of dense connective tissue.
TYPES OF BONES
There are 5 types of bones in the human body. These are long bones, short bones, flat bones,
irregular bones and sesmoid bones.
Long Bones
Long bones are some of the longest bones in the body, such as the Femur, Humerus and Tibia
but are also some of the smallest including the Metacarpals, Metatarsals and Phalanges.
The classification of a long bone includes having a body which is longer than it is wide, with
growth plates (epiphysis) at either end, having a hard outer surface of compact bone and a
spongy inner known an cancellous bone containing bone marrow. Both ends of the bone are
covered in hyaline cartilage to help protect the bone and aid shock absorbtion.
2
,Short bones are defined as being approximately as wide as they are long and have a primary
function of providing support and stability with little movement. Examples of short bones are the
Carpals and Tarsals - the wrist and foot bones. They consist of only a thin layer of compact, hard
bone with cancellous bone on the inside along with relatively large amounts of bone marrow.
Flat bones are as they sound, strong, flat plates of bone with the main function of providing
protection to the bodies vital organs and being a base for muscular attachment. The classic
example of a flat bone is the Scapula (shoulder blade). The Sternum (breast bone), Cranium
(skull), os coxae (hip bone) Pelvis and Ribs are also classified as flat bones. Anterior and
posterior surfaces are formed of compact bone to provide strength for protection with the centre
consisiting of cancellous (spongy) bone and varying amounts of bone marrow. In adults, the
highest number of red blood cells are formed in flat bones.
These are bones in the body which do not fall into any other category, due to their non-uniform
shape. Good examples of these are the Vertebrae, Sacrum and Mandible (lower jaw). They
primarily consist of cancellous bone, with a thin outer layer of compact bone.
Sesamoid bones are usually short or irregular bones, embedded in a tendon. The most obvious
example of this is the Patella (knee cap) which sits within the Patella or Quadriceps tendon.
Other sesamoid bones are the Pisiform (smallest of the Carpals) and the two small bones at the
base of the 1st Metatarsal. Sesamoid bones are usually present in a tendon where it passes over a
joint which serves to protect the tendon.
The human skeleton consists of 206 bones and 32 teeth. The human skeleton also includes
ligaments and cartilage. Ligaments are bands of dense and fibrous connective tissue that are key
to the function of joints. Cartilage is more flexible than bone but stiffer than muscle. Cartilage
3
,helps give structure to the larynx and nose. It is also found between the vertebrae and at the ends
of bones like the femur.
4
, The bones provide structure and protection and facilitate motion. Bones articulate to form
structures. The skull protects the brain and gives shape to the face. The thoracic cage surrounds
the heart and lungs. The vertebral column, commonly called the spine, is formed by over 30
small bones. Then there are the limbs (upper and lower) and the girdles that attach the four limbs
to the vertebral column.
Bones of the human skeletal system are categorized by their shape and function into five types.
The femur is an example of a long bone. The frontal bone is a flat bone. The patella, also called
the knee cap, is a sesamoid bone. Carpals (in the hand) and tarsals (in the feet) are examples of
short bones.
5
