Skeletal System Flashcards
Skeleton
Cranium (10)
Facial Bones (10)
Holes - Mental
Foramen: holes in skull where nerve tissue pass through
Nasal Cavity (3)
There are sinuses.
Infant Skull
Closes after 18 months
Bone structure
Type of connective tissue composed of calcium phosphate(Ca3 (PO4)2)
- Proximal ephiphysis: have articular cartilage
- Diaphysis: Longest part of the bone shaft
- Distal epiphysis: have articular cartilage
- Epiphseal line/plate: made of articular cartilage when it is growth plate –> hardens when you grow older
- Periosteum: tissue that coats outside live bone, preforated
- Medullary caity (lined by endosteum): where bone marrow exists
- Bone ossifies = hardens
- Hyaline cartilage: covers articular surface of epiphysis; provides smooth surface that reduces friction at joint surfaces
- Epiphyses: ends of long bone, each has a thin layer of compact bone and central area of spongy bone; in adults, red marrow, which forms blood cells, is confined to these cavities in the spongy bone of some flate bone and epiphyses
Compact Bone
solid matrix of organic substances and inorganic salts such as calcium phosphate
- Matured bone is layered → lamellar: concentric layers
- Around vascular canals called haversian canals, which contain blood vessels which give nutrients to the osteon
- Immature bones do not have osteons → just a woven mesh of overlapping collagen fibers → makes kids more flexible
- The older you are, the more lamellar the bone gets
- 80% of bone → compact bone; 20% → spongy
Cancellous Bone/Spongy Bone
- Trabeculae (lattice) of spongy bone
- Spaces are filled with bone marrow
- less dense structure and higher surface area than dense bone
- large irregular spaces containing red bone marrow
Cartilage
(found in ears, vertebrae, between pubic symphysis)
- Made by cells called chondroblasts which form →
- Chondrocytes (the actual cells) which form→
- Collagen and elastin fibers (provide flexibility)
Vertebrae
column of irregular bones
Three sections:
- cervical
- thoracic
- lumbar
Thoracic Cage
- True ribs: go from your back and attach to sternum through costal cartilage
- False ribs: do not connect directly to sternum. Their cartilage connects them to one another and the cartilage connects to the sternum
- Floating ribs: only attach at spinal cord
- Clavicle attaches to sternum at the manubrium
Osteoprogenitor
form bone tissue (make → osteoblasts)
Osteoblasts
majority of your bone (make → osteocytes)
Osteocytes
- Maintain bone tissue (make → osteoclasts)
- embedded in a lacuna within the matrix
- mature bone cell
Osteoclasts
reabsorb bone material for development and repair
Bone Function
- Support/locomotion, structure, mineral storage, calcium storage, blood production
- support and protect soft tissues and organs
- enable movement by providing attachment for muscles
*
Types of bones
- Short - wrist, ankle, patella
- cube shaped and contain mostly spongy bone
- Strength upon impact, compactness, shock absorption
- Long - limbs
- Support, locomotion, levers (weight distribution)
- Flat - skull, shoulder blade, ribs
- Protection, muscle attachment
- Irregular
- vertbrae, hip bones, facial bones
Cervical vertebrae
- the “neck” which contains the first 7 vertebrae
- C-1 + C-2 form atlas and axis (pivot joint in your head that allow you to turn head)
- Process on axis is called dens (it allows rotation)
- C-2 + C-5 are forked for muscle attachment
- smallest and lightest of the vertebrae
- always have openings (foramina) through which the vertebral arteries pass
Thoracic vertebrae
- larger than the cervical vertebrae, with a slightly heart shaped body
- transverse processes articulate with the ribs
- spinous process is long and points sharply downward
Lumbar vertebrae
- contains larger bones to support more weight
- large block-like body and short processes
Bone Fractures
- Compound: breaks through two different tissues (ex: through bone and skin)
- Transverse: crack, clean break, could offset the bone
- Greenstick: not completely cut through, on one side → happens in young bones because the bone hasn’t completely ossified
- Spiral: crack happens at angle and spirals down, twisting
- Comminuted: when the bone breaks into several pieces
- Stress: hairline crack
- Vertebral compression: when vertebrae compress because of weight
Bone Repair Steps
- Reactive Phase
- Inflammatory
- Granulation
- Reparative Phase
- Cartilage callus formation
- Lamellar bone deposition
- Remodeling Phase
Reactive Phase
1
happens immediately in the first 6-8 hours of injury
- Inflammatory - the bone bleeds out, forms a bruise (hematoma), blood cells clot and die if close to injury
- Granulation - fibroblasts that survive replicate and form granules, blood supply to the break is cut off
Reparative Phase
2
4-6 weeks after injury → break is immobilized (by the doctor)
- Cartilage callus formation - cells of periosteum replicate and transform, they develop chondroblasts, chondroblasts make cartilage that connects the two breaks
- Distal cells form osteoblasts which form woven bone and aggregate to form fracture callus
- Lamellar bone deposition - ossification of cartilage callus
- Fracture callus is mineralized
- Mineralized matrix become perforated with microvessels
- Osteoblasts populate the site and lay down trabecular bone-
- Trabecular bone replaces the fracture callus (which was softer)
Remodeling Phase
3
(6-8 weeks) replaces trabecular bone with compact bone
- (3-5 years after injury) Trabecular bone is dissolved and reabsorbed by osteoclasts → where the lamellae reform
- Osteoblasts deposit compact bone in lacuna
Joint
- The point at which two bones meet (location)
- Connected by ligaments or fibrous tissue
- cartilaginous, immobile, and synovial joints
Synovial Joint
- allow free movement in one or more planes
- articulating bone ends are separated by a joint cavity contain lubricating synovial fluid
- mobile and happens at the appendicular skeleton
- Moves without pain
- Any synovial joint has articular cartilage
- least stable and most prone to injury
Immobile Joint
- connected by fibrous tissue
- in some, (skull) the bones are tightly bound by connective tissue fibers and there is no movement
- in the skull - in pieces so you can push the baby out
- skull sutures-fibrous
- vertebra-discs(limited motion)
- hips-limited motion
Describe two reasons why the skull bones are not fused into sutures until around 2 years of age.
A) it has to compensate for the brain growth
B) The baby has to fit through the birth canal
Purpose of domed skull
To protect and enclose the brain
Limb Girdles
- attach limbs to the axial skeleton and allow to mvoe more freely
- allow for free and wide ranging movement of the arms and legs
- shoulder girdle: two scapulae and two clavicles
- hip girdle: two hip bones connected anteriorly at the pubic symphsis and posteriorly by the sacrum
- bowl shaped pelvic girdle protects reproductive organs, bladder, and lower parts of gut
- weight bearing! becuase the bones are large and thick
- pubic sumphysis softens during childbirth to allow pelvis to widen
Difference between male and female pelvis
- female pelvis: wider, shallower, and more flared than the male pelvis
- male pelvis: narrower than in females and more heart shaped
cartilaginous joints
- the bone ends are connected by cartilage
- most allow limited movement although some are immovable
osteoporosis
- age related disorder
- bone mass decreases
- loss of height and increased tendency for bones to fracture
- women at greater risk of developing this disease than men because their skeletons are lighter and their strogen levels fall afer menopause (estrogen provides some protection against bone loss)
- younger omwen with low hormone levels and/or low body weight are also affected
- affects the whole skeleton, but especially spine, hips, and legs
- Lose of density → bone becomes more porous than it should
- Unable to absorb calcium and longer because of age
osteoarthritis
- chronic degenerative disease aggravated by mechanical stress on bone joints
- pain, stiffness, inflammation, and full or partial loss of joint function
- occurs in almost all people over the age of 60 and affects three times as many women as men
- weight bearing joints such as those in the knee, foot, hips, and spine are the most commonly affected
Rheumatoid arthritis vs. Osteoarthritis
- Rheumatoid arthritis is an autoimmune disease that can occur at any age and is not caused by lifestyle, whereas Osteoarthritis typically occurs later in life and is caused by wear and tear.
- They are both forms of arthritis.
- Rheumatoid arthritis is a genetic autoimmune disease and can begin at any point in life, while osteoarthritis is caused by mechanical wear later in life.
- Rheumatic: more bone loss, thickened synovial fluid, swelling because of the immune system attacking the joint
- If you stop using the joint, it’ll still be swollen
- Osteoarthritis: bone spurs - bone thickens
- If you stop using the joint, it’ll be less swollen
articular cartilage
- smooth, slippery, porous, malleable, insensitive, and bloodless
- massaged by movement, permitting absorption of synovial fluid, oxygen, and nutrients
periosteum
- fubrous, cellular, vascular, and highly sensitive support sheath for bone, providing nutrient blood for bone cells and a source of steoprogenitor cells throughout life
medullary cavity
- cavity of diaphysis
- contains marrow: red in young, turnning to yellow in many long bones in maturity
- lined by endosteal tissue
Compound Fracture
Compound: breaks through two different tissues (ex: through bone and skin)
Tranverse Fracture
Transverse: crack, clean break, could offset the bone
Greenstick Fracture
Greenstick: not completely cut through, on one side → happens in young bones because the bone hasn’t completely ossified
Stress Fracture
Stress: hairline crack
Spiral Fracture
Spiral: crack happens at angle and spirals down, twisting
Comminuted Fracture
Comminuted: when the bone breaks into several pieces
Vertebral Compression Fracture
Vertebral compression: when vertebrae compress because of weight
Hip Girdle
Types of Synovial Joints
- Types:Gliding
- shrug, clavicle
- Hinge
- Pivot
- Ellipsoidal/Condyloid
- At wrist and ankle
- lateral, circumduct, elevate, depress
- Saddle
- separates humans from primates
- cortical oppositon
- Ball and socket
- Widest range of motion (ROM)
- Rotation, lateral flexion and extension, abduction, adduction
bursa
fluid filled cavity lined with synovial membrane. acts as a cushion (ex: between tendon and bone, or between bones)
ligaments
- made of connective tissue and hold bones together
- strong and flexible but have a poor blood supply
- torn ligaments are slow to heal because of poor supply and use
lactic acid levels in the blood continue to rise for a time after exercise has stopped. explain why this occurs
The body still needs to make up for the O2 depletion after exercising, so it continues to go though anerobic respiration to make up for this, and aerobic respiration also ends up producing lactic acid
Similarities and differences between rigor mortis and physiological contracture
similar:
- heads of myosin fiber attach to the actin fibers, amking the muscle contract
whats the opposite of similar:
- the reason that the muscle stays contracted during rigor mortis is because the dead body is unable to supply more ATP for the muscle to relax
- physiological contracture: the body is able to supply ATP to reprime the myosin heads and to supply calcium to attach to trypomyosin
osteon
Osteon: contains bone cells called osteocytes
lacunae
inside osteon
Lacunae: tiny spaces in bone → where osteocyte lives → oozes out calcium phosphate to make compact bone, which makes the compact bone harder
haversian canal
Haversian Canal: contains veins, arteries, and nerves supplying the bone tissue –> surrouned by a regular arrandement of osteocytes
An amphibian does not have the ability to rotate its hands, while humans can rotate their hands in many different directions due to……
two lower arm bones allow the carpals to twist over the ends
