Animal Anatomy notes (The skeletal system)

 Summary from the video below. https://www.youtube.com/watch?v=RyPzxwYFg3s&feature=youtu.be

Bone is the framework that supports and protect the soft tissues of the body and also serves other functions:

 -leverage (for skeletal muscles and tendons)

-storage (minerals like calcium)

- blood cell formation (hematopoiesis in bone marrow)

 

Bone is the second hardest substance in the body the first being the enamel on your teeth.

Bone is composed of cells embedded in a matrix.The matrix is made up of collagen fibers embedded in protein and polysaccharides the bones structure

There's two different types of bones

1) Cancellous bone/Spongy bone 

 

-light and spongy

-has tiny spicules or holes where bone marrow is found 

 

 

 

- Cancellous bone is found in the centre of long bones (eg of long bones: humerus and femur)

 

 

 2) Compact bone

 - Dense and heavy as opposed to the spongy bone 

- Makes up the shaft of long bones  and the outside layer of all bones

 

-Composed of tiny cylinder bones called haversian system (contains blood lymph vessels and nerves and osteocytes are located within these layers). (Osteo means bone and site means cell.)

 

Haversian system consists of multiple layers of compact bone tissue (lamella) that surrounds a central canal. 

 

The Harversian canal ( contain the bone's nerve and blood supplies which run parallel with the bone). 

 

There are perpendicular canals that connect each Haversian canal and those are called Volkmann's canals.

 

Osteocytes live within their own small space in the compact bone and the Haversian canals and they're called lacuna.

 

Very tiny canals run within the compact bone and Harversian canals, called canaliculi. Osteocytes exchange nutrients and waste through these canaliculi channels. Osteocytes reside in canaliculi, osteocytes are bone cells so the formation of bone happens there.

 

 

 

 

Internal anatomy of that compact bone (Micrograph of a section of compact bone)

 

 

 Articular surfaces just means surfaces where there's going to be movement  

Osteocytes can actually revert back to osteoblast if an injury happens and then they can

continue on with ossification and that's how a fracture actually ends up healing. 

 

If there's a patient that's hypocalcemic or low calcium in the blood the body's automatically going to start taking it from the bones. That's why calcium diet is important. 

Osteocytes are the ones that are going to make bone.

 

 

 

 

 

 

 

Chondral means cartilage.

 

 

 

When taking an x-ray of a pregnant mother you're not going to be able to see the bones until the third trimester. Cartilage ossify into bone.

 

The shaft the middle part of the bone is the diaphysis and then each tip of

that long bone is the epiphysis.

 

Head of the femur gonna go into your acetabulum. Epiphyseal plates gonna stay cartilage until that animal has grown up to its fullest potential and then after that those epiphyseal  plates will then ossify, the bone will not grow any longer.

 

 

 

 

 

 

 

 

Bone marrow fill the spaces within the bones and they're found in long bones solely so in in all the other bones you're not gonna find bone marrow it's within the long bones.

 

Red bone marrow and this is a very important type of bone marrow because hematopoietic tissue is where hematopoiesis.

When an animal is born the majority of their bone marrow is gonna be red bone marrow and that's where hematopoiesis happen there's a lot of growth happening and there's a lot of blood production that there's a lot of blood production that needs to happen and thanks to this bone marrow red bone marrow we can now as you get older a lot of this red bone marrow will turn into yellow bone marrow.

 

 

 

  

 

 Coccygeal which it can absolutely vary depending on the length of the tail.

Ribs will attach eventually to the sternum.

Those two sternebrae are actually named so the very bottom one closer to the so the very bottom one closer to theabdominal cavity is called the xiphoid and then the very first one is called the manubrium.

 

 

Humerus which is connected to that scapula.

After that past the elbow we have the radius in the ulna.

You'll find the radius in the ulna and they're kind of side-by-side.

 

 The pelvic limb we started up at the pelvis.

 

The pelvis itself is made up of three bones and the those three bones are on each side of thepelvis so the pelvis is separated in half to right side and a left side so each side has an ilium and ischium andpubis and then come together at the pubic symphysis which is acartilage there that allows for stretching. For example, when giving birth.

The pelvis itself is connected to a femur.

After the femur before you get to the tibia and fibia, you're gonna haveyour knee which is called a stifle. Below the stifle you're gonna have twobones which is the tibia and the fibula.

Fibula that are gonna also be side by side the tibia.

Metatarsal extend from the hawk down to the tips of your phalanges which are the toes.

Example of synovial joints are elbow and knees.