UNIT 2 Flashcards
What are the functions of the skeleton?
- supporting the soft tissues of our body
- acts as a mineral reservoir for calcium and phosphate
- act as an energy storage
- red blood cell production
- protect our vital organs
- act as a leverage for the movement
Where does our energy storage take place (in bones)?
In the yellow bone marrow
What are the types of connective tissue in our skeletal system?
Dense regular, Adipose tissue, Cartilage, bone, and blood tissue
What is embryonic CT?
All of our connective tissue begins as embryonic connective tissue, better known as mesenchyme.
What is the name of the cells describing dense regular ct?
Fibroblasts: if immature
Fibrocytes: mature
What is the name of the cells in adipose tissue?
Adipocytes
What is the name of the cells in cartilage tissue?
chondroblasts: immature
chondrocytes: mature
What is the name of the cells in bone tissue?
Osteoblast: immature
Osteocyte: mature
What are the general characteristics for cartilage?
- no blood vessels or nerves
- consists primarily of water
- most is surrounded by perichondrium (except fibrocartilage)
- does not continously grow, it stops growing at 18-20
- cartilage has collagen which helps it reduce tension
- Chondroblasts (secrete matrix) and chondrocytes (trapped in lacunae) are the cells
What are the 3 types of cartilage types in our skeletal system?
Hyaline, elastic and fibro
What are the features of hyaline cartilage?
- most abundant
- has fibers
- located at the end of almost all bones, at the growth plate of long bones, and at costal cartilage
What are the features of elastic cartilage?
- many elastic fibers and collagen
- tolerates bending and can recoil
- located in ear and epiglottis
What are the features of fibrocartilage?
- abundant collagen fibers
- can resist twisting and compression
- no perichondrium
- found in intervertebral disc and menisci
What type of bone is at the epiphysis?
Spongy
What type of bone is at the diaphysis?
compact
Every single bone is made up of _______ and ________ bone regions
spongy and compact
What type of cartilage is seen at the epiphysis regions of our bone?
articular cartilage (made of hyaline cartilage)
What is the periosteum?
The membrane surrounding the bone, except near the joint surface (epiphysis)
What features are found in every single bone?
spongy/compact bone, blood vessels, nerves, and lymphatic vessels
What is spongy bone made of?
trabuculae and red bone marrow
How often is spongy bone replaced?
Every 4 years
How does compact bone transmit weight?
Either compression (along medial diaphysis) or through tension (along lateral diaphysis)
Which type of bone forms osteon’s?
Compact bone
How often is compact bone replaced?
every 10 years
What is a unique feature about spongy and compact bone?
They are both made out of the same matrix and can rearrange if the body needs to.
Compact can convert to spongy and spongy can convert to compact
Where can we find osteoblasts/osteocytes in the bone strucutre?
Osteoblasts: are found lining the trabuculae of spongy bone
Osteocytes: reside in the middle of the trabuculae structure (osteoid matrix)
What are the two parts of the osteoid matrix?
Organic: Provides flexibility
Primarily collagen fibers (protein) and resists twisting and tension
Inorganic: This is the part that provides durability and hardness
It is made of calcium and phosphate
What is Ricketts?
This is when we dont have enough calcium and phosphate being stored in our bones. Our bones are ruberry because they have more collagen. This is mainly due to a lack of vitamin D which is supposed to help store calcium
What are the different cells within our bones?
Osteoclasts, osteoprogenitor, osteoblast, osteocytes
What is the role of osteoclast cells?
Their goal is to break down old matrix (osteoid)
When they are active they can break down blood and release calcium and phosphate throughout the blood
What is the role of osteoprogenitor cells?
These will be forming new bone cells
If you break your bone, these cells can become active and can divide/lay down new bone cells
What is the role of osteoblast cells?
They are immature bone cells that secrete the new matrix of the bone
What is the role of osteocyte cells?
These are mature bone cells trapped in lacunae and help give structure (don’t move)
What is canaliculi transfer?
Since osteocytes are trapped in lacunae and surrounded by solid matrix, they cannot move and obtain their nutrients. In this case, we will need canaliculi (channels) to extend from them and allow diffusion of nutrients, gases, etc
What are the 2 ways our bone develop and ossify?
Intramembranous ossification and endochondral ossification
What is intramembranous ossification?
This mainly occurs in the flat bones of the skull and this is when mesenchyme differentiates into osteoblasts. The osteoblasts cluster together, secrete osteoid matrix and develop into osteocytes that will form bone and create trabeculae
What is endochondral ossification?
This mainly occurs in the long bones of our body and in this case, the mesenchyme will differentiate into hyaline cartilage. Over time, the cartilage is replaced by bone . After, there may be hyaline cartilage remaining in the epiphyseal plate which is replaced once you have reached final height
What is appositional growth?
This is when our bones get wider. Osteoclasts will break downthe matrix inside our bone while new born is formed on the outside. our bones will be overall wider but there will still be a hollow center
Why is it important for our bones to be hollow?
Because if they were too heavy, we would not be able to walk
What is interstitial growth?
This is when our bones grow in length. In this process, our bones replace dead cartilage cells and it all occurs on the epiphyseal plate (when growing)
What is the role of the articular cartilage?
keeps bones from grinding to each other
What type of bone marrow is in spongy bone?
Red bone marrow
What is the medulary cavity?
This is the medial region of the inside of bone that holds the yellow bone marrow
What type of bone cell is found in compact bone that provides strnegth?
Osteon
What is at the center of each osteon?
Central canal
What is the area around each central canal called?
Lamellae
What is inside the central canal?
Blood vessels, lymphatic vessels, and nerves
What is the volkmann’s canal?
Unlike the central canal, the volkmann’s canal is the tube in the osteon that travels left and right NOT up and down.
What are the holes around an osteon?
Lacunae, they have osteocytes
What are the branches stemming out of lacunae?
canaliculi
What wraps around the outside of compact bone?
periosteum
What covers the outside of spongy bone
endosteum
What is the difference between concentric lamellae and circumfrential lamellae?
Concentric is the area inside an osteon and circumfrential is the area outside an osteon (around the bone)
Skeletal muscle contracts by __________ contraction.
voluntary
What are some characteristics about muscles?
- Responds to external stimuli
- contracts
- extend without tearing
- Elastic: recoil
Our muscle organ is made of a combination of which cells
Muscle fibers (cells) + connective tissue + epithelial tissue
What is skeletal muscle identified by?
- striations
- cylindrical fibers
- multiple nuclei
- voluntary control
- cannot divide
- fatigue over time
- attached to skeleton and skin
Every muscle organ has…
- one artery, vein, and nerve
- muscle fibers (cells)
- bundles of muscle cells (fascicles)
- connective tissue
- epimysium
- periomysium
- endomysium
Skeletal muscle cells are formed by a fusion of ______
myoblasts: immature muscle cells
skeletal muscles contract when stimulated by ________
neuron signal
A skeletal muscle cell is known as a
muscle fiber
What is the epimysium?
The layer surrounding the entire muscle organ
What is the perimysium?
The layer surrounding a fascicle.
What is the structure of a muscle organ?
Muscle organ is made by fasiciles. Each fasicle contains muscle fibers. Each muscle fiber contains myofibrils. Each myofibril contains sarcomeres
What is the endomysium?
The endomysium is the layer surround the muscle fiber
