Download Physiology Ch 5

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Scapula wikipedia, lookup

Vertebra wikipedia, lookup

Body snatching wikipedia, lookup

Anatomical terminology wikipedia, lookup

Bone wikipedia, lookup

Skull wikipedia, lookup

Chapter 5 The Skeletal System
skeletal system
- consists of:
skelton - composed of 206 bones
2 divisions of the skeleton:
axial skeleton
- longitudinal axis of body
appendicular skeletal - bones of limbs and girdles
functions of the bones:
blood formation
- internal framework
- supports and anchors all soft organs
- bones protect soft body organs
- skeletal muscles attach to bone by tendons and use the bones as levers to
move body
- fat is stored in bone cavities
- bone tissue stores minerals (calcium, phosphorus, etc.)
- calcium ions (Ca2+) needed in blood for the nervous system to
transmit messages, for muscles to contract, and for blood to clot
- hormones control movement of calcium to & from bones
- hematopoiesis (formation of blood cells) occurs in bone marrow cavities
2 types of osseous (bone) tissue:
- dense; looks smooth
- made of needlelike bone pieces; has lots of open space
4 groups of bones (based on shape):
long bones
- longer than they are wide
- shaft with heads at both ends
- made mostly of compact bone
- examples: all bones of limbs (except wrist & ankle bones)
short bones
- generally cube-shaped
- made mostly of spongy bone
- examples: wrist & ankle bones
sesamoid bones
- special type of short bone
- form within tendons
- example:
patella (kneecap)
flat bones
- thin, flat, and usually curved
- composed of spongy bone sandwiched by 2 thin layers of compact bone
- examples: most skull bones, ribs, and sternum (breastbone)
irregular bones
- don’t fit in a preceding group
- examples: vertebrae, hip bones
long bone structure
Sharpey’s fibers
articular cartilage
epiphyseal line
epiphyseal plate
medullary cavity
bone markings
- shaft
- made of compact bone
- fibrous CT membrane which covers the diaphysis
- AKA perforating fibers
- CT fibers that attach periosteum to bone
- ends of long bones
- composed of spongy bone enclosed by a thin layer of compact bone
- covers epiphyses (no periosteum)
- hyaline cartilage
- smooth, slippery surface; decreases friction at joints
- thin line separating epiphysis from diaphysis
- remnant of the epiphyseal plate
- AKA growth plate
- plate of hyaline cartilage in a young growing bone
- lengthwise growth of a long bone occurs here
- by end of puberty, they are replaced by bone leaving epiphyseal lines
- cavity of the shaft
- primarily stores adipose tissue (yellow marrow)
- contains red marrow in infants (blood cells made)
- in adults red marrow is confined to spongy bone cavities
- bumps, holes, and ridges
- reveal where muscles, tendons, and ligaments were attached and where
nerves and blood vessels passed
- 2 types:
- grow out from bone surface
depressions - indentations in the bone
microscopic long bone structure
- bone cells; found in lacunae
- tiny cavities in bone matrix which contain osteocytes
- concentric circles of bone tissue containing lacunae
- surround central canals
central canals
- AKA Haversian canals
- run lengthwise through matrix
- contain blood vessels and nerves
- AKA Haversian system
- consists of central canal and surrounding rings (lamellae)
- tiny canals that radiate outward from central canals to lacunae
- allow bone cells to receive nutrients
perforating canals
- AKA Volkmann’s canals
- run at right angles to the shaft
- allow communication between inside and outside of bone
bone tissue
- very hard (due to calcium salts)
- flexible (due to collagen fibers)
bone formation
embryo skeleton
young child
- mostly hyaline cartilage
- cartilage has been replaced by bone
- hyaline cartilage is “ossified” into bone
- 2 phases:
* hyaline cartilage is covered with a bone matrix by osteoblasts (bone-forming cells)
* cartilage is digested away forming medullary cavity
long bone growth
- controlled by hormones (growth hormone, sex hormone)
- ends during adolescence (epiphyseal plates completely converted to bone)
parathyroid hormone (PTH) - produced by parathyroid glands when blood levels of calcium are low
- activate osteoclasts (bone-destroying cells)
- break down bone matrix and release calcium into blood
stresses of muscle pull and gravity
physically inactive people
- cause bones to become thicker and form projections
to increase their strength
- bones loses mass & atrophy because they are no longer subjected to stress
rickets - disease of children
- bones don’t calcify due to lack of calcium or vitamin D (needed for calcium absorption)
- bones soften and legs become bowed
bone fractures - breaks
- during youth, most result from trauma during sports or car accidents
- more frequent in old age
closed (simple) fracture
open (compound) fracture
common fractures:
- bone breaks cleanly; doesn’t penetrate the skin
- ends of bone penetrate skin
- bone breaks into fragments (common in old age)
- bone is crushed (common in old age)
- broken bone portion is pushed inward (typical in skull fractures)
- ends of broken bones are pushed into each other
- common when trying to break a fall with outstretched arms
- excessive twisting forces cause a ragged break (common in sports)
- incomplete break, like a green twig (common in children)
treatment of a broken bone
- bone is realigned
- doctor uses his hands with closed fractures
- surgery necessary with open fractures
- cast or traction
healing time for a simple fracture
bone healing
hematoma forms
fibrocartilage callus forms
bony callus forms
bone remodeling occurs
axial skeleton - 3 parts:
- 6-8 weeks (longer for larger bones and in the elderly)
- due to broken blood vessels
- contains cartilage and bone matrix and cartilage fibers
- made by CT cells
- closes the gap and “splints” the bone
- made of spongy bone by osteoblasts
- replaces fibrocartilage callus
- bony callus remodeled into a strong permanent patch
vertebral column
bony thorax
skull - cranium encloses and protects brain
- facial bones hold eyes in place and allow facial muscles to produce facial expressions
most bones joined together by sutures (immovable joints)
sinuses - air spaces in bone
- composed of 8 flat bones:
frontal bone
- forms forehead and superior part of each orbit (eye socket)
parietal bones
- paired bones
- form most of superior and lateral walls of cranium
temporal bones
- paired bones
- inferior to parietal bones on each side
- important markings:
external acoustic meatus
- ear canal
styloid process - needlelike just below EAM
- many neck muscles attach here
zygomatic process
- joins cheek bone
mastoid process
- below and behind EAM
- neck muscles attach here
jugular foramen
- where occipital and temporal bones meet
- jugular vein passes through
carotid canal
- anterior to jugular foramen
- carotid artery passes through
occipital bone
- forms floor and back wall of skull
- important markings:
foramen magnum
- large opening at base of occipital bone
- spinal cord passes through
occipital condyles
- rockerlike projections
- rest on first vertebrae
sphenoid bone
- butterfly-shaped
- forms part of cranial floor and eye orbits
- important markings:
sella turcica - depression that holds pituitary gland
optic canals - optic nerve passes from brain to eyes
ethmoid bone
- anterior to sphenoid
- forms roof of nasal cavity and part of orbits
facial bones - 14 bones (12 are paired)
maxillary bones
- form upper jaw and anterior hard palate
- carry the upper teeth
- paranasal sinuses
- drain into nasal passages
- throat infections can spread here causing sinusitis
palantine bones
- form posterior hard palate
- cleft palate
zygomatic bones
- cheekbones
- also form part of orbits
lacrimal bones
- form part of orbits (fingernail size)
- each has a groove for the passage of tears
nasal bones
- form bridge of nose
vomer bone
- forms nasal septum
inferior nasal conchae - part of nasal cavity
- lower jaw
- joins temporal bones on sides of face
- carries the lower teeth
hyoid bone
- “Adam’s apple”
- not really part of skull
- suspended in midneck region
- moveable base for tongue and attachment point for neck muscles that raise
and lower larynx when we swallow or speak
- soft spots in fetal skull
- fibrous membranes not yet turned to bone
- allow skull to be compressed during birth
- also allow for brain growth
vertebral column
- AKA spine
- flexible, curved structure extending from skull to pelvis
- made of 26 irregular bones connected by ligaments
- spinal cord runs through its central cavity
- 24 of them
intervertebral discs - pads of fibrocartilage
- cushion vertebrae and absorb shocks
- herniated disc (slipped disc) - intervertebral disc protrudes
- may cause numbness and excruciating pain
vertebrae structure:
- disklike; bears weight
- arch extending from the body
- spinal cord passes through
transverse processes - lateral projections from arch
spinous process
- projection from posterior part of arch
articular processes
- allow vertebra to form joints with adjacent vertebrae
cervical vertebrae
- 7 of them  C1 – C7 (think: breakfast at 7AM)
- form neck region of spine
atlas (C1)
- holds skull
- no body
axis (C2)
- acts as a pivot for atlas
- has odontoid process (pivot point)
thoracic vertebrae
- 12 of them  T1 – T12 (think: lunch at 12 noon)
lumbar vertebrae
- 5 of them  L1 – L5 (think: dinner at 5 PM)
sacrum - formed by the fusion of 5 vertebrae
- joins with L12 above and the coccyx below
- forms posterior wall of pelvis
- joins with hip bones (sacroiliac joints)
coccyx - formed by the fusion of 3-5 vertebrae
- “tailbone”
bony thorax - made of sternum, ribs, and thoracic vertebrae
- AKA thoracic cage
- breastbone
- forms from the fusion of 3 bones:
- superior
- middle
xiphoid process
- inferior
- bony landmarks:
jugular notch
- concave upper border of manubrium
sternal angle
- manubrium and body meet at a slight angle
xiphisternal joint
- where body & xiphoid process meet
- 12 pairs
- forms wall of bony thorax
- all attach to vertebral column and then curve downward and toward anterior body
true ribs
- first 7 pairs
- attached to sternum by costal cartilages
false ribs
- next 5 pairs
- attached to sternum indirectly by cartilage
floating ribs - last 2 pairs
- not attached to sternum
appendicular skeleton - bones of the shoulder girdle, upper limbs, pelvic girdle, and lower limbs
shoulder girdle (pectoral girdle)
very flexible yet easily dislocated
consists of:
- collarbone
- attaches to manubrium of sternum and scapula
- acts as a brace holding arm away from thorax
- shoulder blade
- loosely held in place by muscles
- glenoid cavity
- shallow socket that receives head of arm
upper limbs
30 bones form each upper limb (arm, forearm, and hand)
- heads fits into glenoid cavity
radius - lateral to ulna (on thumb side) in anatomical position
- connected to ulna by interosseous membrane
ulna - medial to radius in anatomical position
carpals - 8 of them (2 rows of 4)
- form the wrist
metacarpals - 5 of them
- form palm of hand
- heads form knuckles
- 14 of them
- form fingers
- 3 in each finger (proximal, medial, and distal)
- 2 in the thumb (proximal and distal)
pelvic girdle
formed by 2 coxal bones (hip bones)
bears the weight of upper body
each hip bone consists of:
- connects to sacrum posteriorly
- large, flaring bone
- inferior part of hip bone (“sit-down bone”)
- pubic bone
- most anterior part of hip bone
acetabulum - deep socket formed at site where the 3 hip bones join
- head of femur fits here
lower limbs
30 bones form each lower limb
femur - thigh bone
- heaviest, strongest bone in body
- head fits into acetabulum of hip bone
- neck of femur
- frequently fractured in elderly
patella - kneecap
- shinbone
- larger and more medial than fibula
- forms inner bulge of ankle
- connected to fibula by interosseous membrane
fibula - thin bone
- forms outer bulge of ankle
- 7 of them
- form back of foot (tarsus)
- heelbone
- 5 of them
- form sole of feet
- 14 of them
- form toes (3 in each toe, except great toe which has 2)
joints - AKA articulations
- hold bones together
- give skeleton mobility
types of joints (based on function)
synarthroses - immovable joints
amphiarthoses - slightly immovable joints
- freely movable joints
types of joints (based on structure)
fibrous joints
- fibrous tissue separates bones
- immovable
- example:
sutures of the skull - CT fibers bind bones tightly
cartilaginous joints - cartilage separates bones
- most are slightly immovable (some immovable)
- examples: pubic symphysis
- joins pubic bones together
intervertebral joints - fibrocartilage discs join vertebrae
epiphyseal plates
- hyaline cartilage
joints between ribs and sternum
synovial joints
- bones separated by a cavity filled with synovial fluid
- freely movable
synovial joints - all have 4 features:
articular cartilage
fibrous articular capsule
joint cavity
- hyaline cartilage covering bone ends
- sleeve of fibrous CT enclosing joint surfaces
- lined with a synovial membrane
- enclosed by the capsule
- contains synovial fluid for lubrication
- reinforce joint
- flattened sacs lines with a synovial membrane & filled with synovial fluid
- often part of synovial joints
tendon sheaths - long bursa that wraps around a tendon subject to friction
types of synovial joints
plane joint
- short gliding movements
- example:
intercarpal joints of the wrist
hinge joint
- angular movement in 1 plane (back-and-forth)
- examples: elbow joint
ankle joint
joints between phalanges of the fingers
pivot joint
- rounded end of 1 bone fits into a sleeve or ring of bone
- example:
atlas and dens of the axis
condyloid joint
- moving bone moves from side to side and back and forth
- example:
knuckle joints (metacarpophalangeal)
saddle joint
- moving bone moves from side to side and back and forth
- example:
thumb joint ( carpometacarpal)
ball-and-socket joint - spherical head of 1 bone fits into a socket of another bone
- allow movement in many directions
- most freely moving joints
- examples: shoulder
- bones is forced out of its normal position
- process of returning the bone to its proper position
- should only be done by a physician
bursitis - inflammation of bursae or synovial membrane
sprain - ligaments or tendons reinforcing a joint are stretched & damaged
- extremely painful
- heal slowly (poor blood supply)
- 1 out of 7 Americans suffer from it
- over 100 inflammatory or degenerative diseases that damage the joints
- joints are painful, stiff, and swollen
osteoarthritis - most common form of arthritis
- affects the aged
- joint cartilage softens and breaks down over the years
- exposed bone can thicken to form bone spurs which restrict movement
- progresses slowly and is irreversible
- rarely crippling
rheumatoid arthritis
- chronic inflammatory disease
- autoimmune disease
- many joints affected (especially fingers, wrists, ankles, & feet)
- bones ends can become fused and/or deformed
- may be severely crippling
- uric acid accumulates in blood and is deposited as needle-like crystals in the joints
- agonizingly painful
- often affects the great toe
- bone-thinning disease
- bones become fragile
- vertebrae often collapse resulting in a hunched-over posture