Skeletal system Flashcards
How many bones in an adult human body
206 named bones
How many bones roughly does an infant have?
Approx 300
What are the main roles of the skeletal system?
To provide structural support
Production of RBC in red bone marrow via hemopoieses
Stores minerals e.g., Ca and P
Protects internal organs
What are the 3 types of cartilage?
Hyaline
Elastic
Fibrocartilage
What is the cartilage made up of and it’s properties?
Mostly water, it contains no blood vessels or nerves
Cartilage is very flexible and strong, it can be compressed and then reversed to its original shape. The thickness of the cartilage causes diffusion of nutrients to pass through the matrix to enter cells
What is the perichondrium?
The perichondrium surrounds the cartilage, it is a dense irregular tissue. It acts as a reinforcement and prevents external expansion. It has blood vessels. No perichondrium at synovial joints
Describe elastic cartilage
Contains more elastic fibres than hyaline cartilage
Are involved in repeated bending movements
Found only in external ear and epiglottis
Describe hyaline cartilage
is the most abundant form of cartilage,
involves in structural support and flexibility
Has spherical chondrocytes
Only fibre is collagen fibres
It covers the end of most movable joints (articular cartilage)
Connects the ribs to sternum (costal cartilage) aids in respiring
Supports the nose (nasal cartilages) and the respiratory system (respiratory cartilage)
Contain perichondrium
Describe fibrocartilage
Consist of parallel rows of chondrocytes which alternate with thick collagen fibres
Can be highly compressed and contain great tensile strength
Found in locations associated with stretch and pressure e.g., knees and discs between vertebrae
Acts as shock absorbers
Protects integrity of skeleton
Name the 2 types of growth of cartilage
Appositional growth and interstitial growth
Explain appositional growth
cartilage forming cells surrounding the perichondrium secrete a new matrix against the external face of the existing cartilage tissue
Explain interstitial growth
Interstitial growth: the lacunae bound chondrocytes divide and secrete and new matrix which expands the cartilage from within, stops growing during adolescence when the skeleton stops growing
Describe the similarities and differences between bone and cartilage
Bone and cartilage both are surrounded by the perichondrium, they both use appositional growth, however only cartilage uses interstitial growth. Cartilage has no blood vessels or nerves unlike bones which do. Cartilage has chondrocytes whereas bones contain osteocytes
Cartilage’s matrix is made by chondrocytes whereas bones is made by osteoblasts
Describe the functions of the bones
Support: bones provide framework that supports and cradles organs, e.g., bones for lower limbs support the body trunk when we start, ribcage supports thoracic wall
Protection: fused bones of skull protect the brain, the vertebrae support the spine, ribcage supports vital organs
Anchorage: skeletal muscles that attach to tendons, use bones as levers to move the body and its parts. This allows us to walk and breathe. The design of joints determines the movements
Mineral storage: Bone is used for storage of minerals (calcium and phosphate), these are released into bloodstream in ion form to be distributed. Withdrawals and deposits of minerals from bones goes on continuously
Blood cell formation made in the bone marrow via haemopoiesis, (red marrow)
Triglyceride: fat is stored in the bones, yellow marrow in cavities
Hormone production: osteocalcin is produced in bones which regulates insulin production, glucose homeostasis and energy expenditure
Name the divisions of the skeleton
Appendicular skeleton & axial skeleton
Explain appendicular skeleton
The appendicular skeleton refers to limb bones and the pelvic girdle, these bones are involved in movement and response to our environment
Explain the axial skeleton
The axial skeleton refers to the long bones of the body, e.g., ribs, vertebrae
These bones are involved in protection of our internal organs, anchoring organs in place & support