Anatomy- the human skeleton Flashcards
what are the functions of the human skeleton?
-support
-protect
-locomotion
-mineral reserve
-haematopoiesis
what is bone made of?
functional units called osteons (haversian system)
what is the composition of osteons?
30% organic -type 1 collagen
70% inorganic - calcium and phosphate salt
what are osteoblasts
lay down new bone
what are osteoclasts
break down old bone
what is rickets?
caused by a vid D deficiency, vit d is requited for calcium absorption, bones become overly flexible as they lack mineral content
what is osteogenesis imperfecta?
it is a genetic disorder which affects collagen production, bones become brittle and fracture easily
what are long bones?
-longer than wide
-long shaft
-bones of the limbs eg femur
what are short bones?
-wider than their length
-similar to long bones
-bones of wrist and ankle
what are flat bones?
-thin and flat, usually curved
-eg the skull, sternum, scapula
what are irregular bones?
-dont fit in the other categories
-vertebrae, sacrum, facial bones
what are sesamoid bones?
-small round bones embedded in tendons
-protect tendon and increase movement
what is the function of the type I collagen
allows bending to occur, provides strength
what is the function of the inorganic structure
makes bone sturdy and gives compressive strength
how is collagen laid out?
collagen fibres run in opposite direction so bone can withstand force from opposite directions
what is the function of the long tube like diaphysis?
-strong but has some flexibility
-mostly compact bone
what is the function of the two epiphyses?
-articular surfaces for joints
-mostly spongy bone but compact on surface
what is the function of epiphyseal growth plate?
-seperates diaphysis and epiphyses
-site of growth
-once growth complete, plate ossifies -> epiphyseal line
what is the function of periosteum?
-covers outer surface of the bone
-site of attatchment for tendons
what is the function of endosteum?
lines internal surfaces of cavities with bones
how do bones grow?
bone can only be laid onto a surface, they can’t divide. in order to grow bones need to have the growth plate made up of cartilage as they can grow by apositional growth and interstitial growth. eg cartilage is able to grow from the middle out
what is apositional growth?
the increase in the diameter of bones by addition of bony tissue at the surfaces of bones.
what is interstitial growth?
the process that adds or removes solid mass at locations inside a solid material.
how many bones does the normal body have generally ?
206
how many bones do newborns have?
270
how are bones connected?
joints
what are fibrous joints?
don’t allow movement, found between bones of scull (sutures)
what are cartilaginous joints?
have a layer of cartilage between the two connecting bones
what are synovial joints?
have a gap between two bone surfaces. allow a much greater range of movement (eg numerous )
what is the axial skeleton?
- skull (22)
-vertebral column (33)
-ribs (12 pairs)
-sternum
what is the appendicular skeleton?
-pectoral girdle
-bones of the arms/hands
what is the lower limb?
-pelvic girdle
-bones of the legs/ feet
what is the viscerocranium?
the facial skeleton (14 bones)
what is the neurocranium?
surrounding the brain (8 bones)
what groups make up the vertebral column?
-cervical
-thoracic
-lumbar
-sacrum
-coccyx
cervical
-7 bones
-small relatively mobile
-most susseptible to dislocations
thoracic
- 12 bones
-articulate with ribs
-long processes for muscle attatchment
lumbar
-5 bones
-largest body
susceptible to herniated IVD’s
sacrum
-5 fused bones
-vertebrae fused
-articulates with hip bones
coccyx
-4 fused bones
-tailbone
-can fracture If land on it
what are the girdles
the part of the skeleton that attach the limbs to the body. pectoral girdle and pelvic girdle
pectoral girdle
-clavical (connects to sternum) and scapula (embedded in muscle)
-clavicle is the only bone connecting upper limb to axial skeleton
-facilitates movement
pelvic girdle
-innominates (unnamed)
-illium, ischium, pubis
-provides stability
-transfers weight to limbs
-protects pelvic organs
-diff shape in M&F
what is the structure of the upper limbs?
-arm > humorous
-forearm > radius and ulna
-wrist > carpals (8)
-hand > metacarpals (5), phalanges (14)
what is the structure of the lower limbs?
-thigh > femur
-leg > tibia and fibula
-ankle > tarsals (7)
-foot > metatarsals (5), phalanges (14)
what are condyle/epicondyle bone markings?
rounded parts of bone which form joint surfaces and attach muscles
what are crest/line bone markings?
ridges of bone which form where muscles are attached
what are facet bone markings?
forms a joint surface, a flat surface
what are foramen/notch bone markings?
a notch with a ligament turning it into something
what are fossa bone markings?
a dip in a bone
what are process/protuberance/spine bone markings?
bumps where muscles attach
what are trochanter/tubercle/tuberosity bone markings?
bumps where muscles attach
what do the sternum and ribs do?
surround and protect thoracic organs. they play an important role in respiration and are flexible due to costal cartilages anteriorly
What are osteons?
The functional unit of bone. They each have a central canal for blood vessels and they are formed from circular layers of bone (lamellae) containing trapped bone cells = osteocytes
What are trabeculae?
Help to transfer weight through the bone
What are osteocytes?
Mature osteoblasts that have became trapped in the bone matrix in little caves called lacunae. They are important as they can respond to mechanical strain and can send signals to initiate bone formation or resportion. ( ie they are important for bone homeostasis)
What are osteoprogenitor cells?
Stem cells which differentiate into osteoblasts or osteocytes
What is trabeculae?
A fine lattice work of thin bony plates at the upper and lower ends of the bone
what are the 5 zones within the growth plate?
Resting, zone of proliferation, zone of hypertrophy, zone of calcification and blood vessels and bone cells invade the calcified cartilage and begin to replace the structure with bone
What is the growth plate formed from?
Hyaline cartilage
What is ossification?
The process in which bone is made
What is endrochondrial ossification?
Cartilage model made first and replaced. model is made first in cartilage which is then replaced by bone. eg femur
What is intramembranous ossification?
Bone formed directly in mesenchyme. generally in the bones surrounding the brain
What is primary ossification centre?
First part to form
What is the secondary ossification centre?
Epiphysis
what are fontanelles?
soft spots which allow flexibility and allow rapid growth of brain during first 2 years of life.
what are the joints between the bones of the skull called?
sutures which are fibrous joints the allow very limited movement
what is osteoporosis?
bone removed faster than laid down and bone density is reduced which makes it more susceptible to fracture. more common in post menopausal women as oestrogen promotes osteoblast activity
what is periostitis?
inflammation of the periosteum. excess bone. if caused by infection generally acute. if caused by trauma/stress generally is chronic.
What is the name for the perpendicular branches connecting the blood vessels of adjacent osteons in the bone microstructure?
Volkmanns canals
What is synchondrosis?
Bones connected by hyaline cartilage and permit no movement
What is the dipole?
Where bone marrow is found in flat bones
What feature of long bones do short bones lack?
Medullary cavity
What serves as the buttresses (supports) on bones where large muscles attach ?
Ridges, crests, tubercles
What is needed in the growth plate for new bone growth?
Cartilage
What nerves control constriction or dilation of blood vessels, regulating blood flow through bone marrow?
Vasomotor
How many nerve endings does the bone itself have?
Not many, sparsely populated with nerve endings, periosteum has much more
Is cartilage vascular or a avascular?
Avascular, cells obtain oxygen via diffusion
Which type of connective tissue is predominantly present in a synchondrosis joint?
Hyaline cartilage
Which type of joint is held together by an interosserous membrane ?
Syndesmosis
