APK 2100c Exam 2 Nguyen

3 components of skeletal system

bones, joints, and cartilages

what type of tissue is cartilage

connective

hyaline cartilage

"frosted-glassy" looking tissue that consists of a small number of cells and an extracellular matrix with many small collagen fibrils

-relatively firm, strong, relatively flexible

-found in locations that need some hardness for protection and support but also some flexibility for movement

-ends of long bones, at the growth plates within bones, in respiratory structures, costal cartialges

before bones become bones they are

hyaline cartilage

elastic cartilage

similar to hyaline, except it also has elastin fibers

-ability to stretch and recoil

-outer ear and epiglottis

fibrocartilage

-many layers of highly condensed collagen fibers

-consists of rows of round chondrocytes among parallel rows of densely packed collagen fibers

-shock absorption

-menisci of knee and cartilaginous discs between the vertebrae

Perichondrium

layer of dense irregular connective tissue surrounding the cartilage

functions of bones

support, protection, movement, mineral storage, hemopoiesis, metabolism, and energy storage

long bones

longer than they are wide with 2 distinct ends - long due to their shape NOT size... think of phalanges!

- skinny midd with two distinct ends

flat bones

thin and flattened, with a pronounced curvature

-sternum, scapula, cranial bones

-ribs

short bones

roughly cuboidal in shape

-include the talus, carpals, tarsals

sesamoid bones

subclass of short bones, look like sesame seeds

-form inside tendons and ligaments and change the leverage of a joint

-patella

irregular bones

have a different shape that does not fit nicely into any of these three groups

-os coxae

compact bone tissue

consists of many individual units called osteons which consist of a central canal surrounded by several concentric rings called lamellae

-runs around the outside of bones

-much denser and harder than spongy bone tissue

Osteoporosis

A condition in which the body's bones are unhealthy and porous and brittle

diaphysis

long shaft of bone, which exists between the two epiphyses

-wall predominantly made of compact bone tissue

epiphyses

two ends of the bone

-proximal and distal

metaphysis

region where the diaphysis meets the epiphysis - location of the epiphyseal plate and line

epiphyseal plate

hyaline cartilage found in the metaphysis of growing bones

epiphyseal line

remnant of the epiphyseal plate, seen in adult bones

articular cartilage ( in bones )

hyaline cartilage that can be found at the end of articulating bones

-smooth white tissue that covers the ends of bones in joints

-not found at the diaphysis

medullary cavity

hollow cavity that runs down the middle of the diaphysis - filled with yellow bone marrow, which is adipose tissue

nutrient foramina

minute holes in the bone surface that allows blood vessels to penetrate

periosteum

thick membrane found on the outside of bones where it is not covered by articular cartilage - gives bone a whitish outer covering

-2 layers: superficial of dense irregular connective tissue and a deep layer that is osteogenic with osteoblasts and osteoclasts

What does it mean to be osteogenic

creates new bone cells

perforated collagen fibers

aka Sharpey's fibers - collagen fibers that wedge themselves into bone tissue and attach periosteum to the bone - found in greatest abundance on parts of the bone where muscles attach

tendon

piece of dense regular connective tissue whose collagen fibers form a tight link with the perforated fibers of the periosteum, linking muscle to bone

endosteum

thin membrane found on inside of bones - lines trabeculae of spongy bone in the medullary cavity and epiphyses as well as the central canals of osteons

-osteogenic

-highly vascularized

Osteon

aka Haversian system - fundamental functional unit of compact bone

-long, cylindrical structures that consist of a central canal (haversian canal) surrounded by several concentric rings of compact bone tissue called lamellae

osteocytes exist in

lacunae

perforating canals

Volkmann's canals- allow the transfer of blood between the central canals of different osteons - connect osteons to one another and the periosteum

canaliculi

small traverse canals through which the pointy branches of the osteocytes can communicate with one another through gap junctions

-osteocytes are able to engage in metabolic coupling

interstitial lamellae

fill in the gaps between the circular osteons using remains of old osteons

circumferential lamellae

lamellae of compact bone that have a parallel arrangement near the surface of compact bone - form a circumference around all of the osteons - make it such that the outside of the bone is smooth and continuous

spongy bone microscopic anatomy

much less complex - consists of solid trabecular that have no cavities or vessels and covered with endosteum which provides the tissue with nutrients it needs

-blood vessels snake through the pores

osteogenic cells

bones stem cells- readily multiply and divide in order to produce new osteoblasts

osteoblasts

immature bone cells that do not divide - found on the superficial layer of the trabeculae

osteocytes

formerly known as osteoblasts but have become trapped in matrix and matured

osteoclasts

demineralize or dissolve bone tissue - multinucleated and have a "ruffled" border that increases the surface area of the cell

ossification

process by which bone forms

what are the 4 situations in which new bone forms?

-when bone is formed in the embryo

-when the bones grow until a person reaches adulthood

-as the bone is remodeled throughout one's life

-when a bone is fractured and must be repaired

intramembranous ossification

formation of bone from within a membrane of mesenchyme

-mesenchymal cells differentiate into osteoblasts, which secrete osteoid - calcified osteoid is laid down in a network of blood vessels called woven bone and lamellar bone replaces the woven bone

-cranial bones, facial, and clavicle

endochondral ossification

formation of bone from within hyaline cartilage -when hyaline cartilage is turned into osseous tissue

-al bones from base of skull down (except clavicles)

how do bones get longer

1) Cartilage growth on the epiphysis side of the epiphyseal plate

2) Replacement of cartilage by bone on the diaphysis side

How do bones get wider?

Osteoblasts in the periosteum add bone tissue to the circumferential lamellae

Osteoclasts remove bone from the inner diaphyseal wall at about the same rate

bone remodeling

process in which bone is continuously deposited and removed mostly at the endosteal surface

-bone deposition and resorption

what type of bone is replaced more quickly?

spongy every 3-4 whereas compact is 10

red marrow

consists of hemopoetic stem cells that grow into red blood cells, platelets, and white blood cells

joint

the point at which the rigid elements of the skeleton come together

We can classify joints....

structurally and functionally

What are the two structural criteria of joints?

-the presence or absence of a synovial cavity

-the type of connective tissue between the bones

what are the three structural classifications of joints?

-fibrous, cartilaginous, synovial

synarthrotic joints

immovable joints

Amphiarthrotic joints

slightly movable

diarthrotic joints

freely movable

fibrous joints

-held together by dense collagen fibers and do not have synovial cavities

-3 types: sutures, syndesmoses, and gomphoses

sutures

joints held together by dense, short, interconnecting collagen fibers

-found among the interlocking cranial bones that form the skull

-synarthrotic

syndesmoses

joints held together by ligaments, such as the joints that join the fibula and tibia and the interosseus membrane between the radius and ulna

-no synovial cavity nor fluid between the bones

-fiber length determines joint movement- short tight fibers allow little movement

-amphiarthrotic

gomphoses

peg-in-socket articulations - such as tooth held in the socket of the alveolar process by a periodontal ligament

-synarthrotic

cartilaginous joints

held together by cartilage and do not have synovial cavities

-2 types: synchondroses and symphyses

synchondroses

joints held together by hyaline cartilage

-epiphyseal plate in a developing bone is hyaline cartilage that holds together two bones, forming a temporary synchondrosis

-synarthrotic

symphyses

held together by fibrocartilage - found on the midline of the body -joints between the vertebrae and the pubic symphysis

-amphiarthrotic

-shock absorption

synovial joints

held together by ligaments

-have synovial cavities

-diarthrotic

-most joints in the body

synovial capsule

sleeve-like capsule that encloses the synovial cavity

outer fibrous capsule

outermost layer of the synovial capsule- mostly dense irregular CT proper

-continuous with the periosteum of the bone

inner synovial membrane

covers the surface of the bone inside the joint that is not covered by hyaline cartilage

-responsible for secreting the synovial fluid into the synovial capsule - loose CT proper

synovial fluid

viscous fluid that has the goopy consistency of raw egg whites - 2 functions:

-reducing friction

-supplying oxygen and nutrtients

weeping lubrication

pressure on joints squeezes synovial fluid into and out of articular cartilage

-when the articular cartilage is compressed, synovial fluid is squeezed out

articular cartilage ( with joints )

at either end of the epiphyses consisting of hyaline cartilage

-provide smooth surfaces for the ends of the bones to interact with one another (reducing friction) and they also play a role in shock absorption

articular discs

consist of fibrocartilage inside the join cavity itself - present in some synovial joints

-shock absorption

-help the bones "fit" together

What are the three reinforcing ligaments?

intracapsular, extracapsular, and capsular

intracapsular reinforcing ligaments

found inside the joint cavity

-anterior and posterior cruciate ligaments of the knee

extracapsular reinforcing ligament

-outside the capsule

ex. medial collateral and lateral collateral ligaments of the knee

capsular reinforcing ligaments

fused with the dense irregular tissue in the outer membrane of the joint capsule

-portion of the capsule to look thickened

-external ligaments of the hips and glenohumeral of the shoulder joint

nervous innervation in synovial joints

several nerve fibers

-pain and stretch information

vascularization in synovial joints

synovial joints are highly vascularized with a rich blood supply

functional redundancy

multiple nerves and vessels that supply the area

bursa

thins saclike structure that contains a small amount of synovial fluid -allows 2 surfaces to slide across one another

-popeyes elbow

tendon sheaths

tube-like elongated bursae that wrap around tendons like a hot dog bun

-found on tendons that experience friction such as in the hand and carpal region

what are the types of synovial joints

plane/gliding, hinge, pivot, condyloid, saddle, ball and socket

What are the three main types of movement at synovial joints?

gliding, angular, rotational

gliding movement

occurs when flat structures of two bones slide across each other

angular movements

occur when the angle between the articulating bones changes

5 subcategories : flexion, extension, abduction, adduction, circumduction

rotational movements

occur when a bone can be turned around the longitudinal axis

2 types: medial and lateral

planar joints

articular surfaces are flat planes which slide back and forth in a motion called gliding

-surfaces separated by hyaline cartilage

-nonaxial

-intercarpal joints in the hands and intertarsal in the feet

hinge joints

a bone with cylindrical end fits into a trough-shaped surface of another bone, allowing flexion or extension

-uniaxial

hyperextension

extension goes beyond anatomical position

-bend backward and bring your trunk closer to your thighs

femorotibial joint

knee joint - between the femur and tibia- largest and most complex joint - extremely stable, modified hinge joint

-condyles of femur interact with condyles of tibia like tires on a road

femoropatellar joint

joint between inferior end of femur and patella

-allows patella to glide along the femur when the knee bends- hinge joint

lateral and medial menisci

C-shaped cartilages within joint capsule- attach to the condyles of the menisci, stabilizing joint and evening the distribution of the compressive load put on the tibia

posterior cruciate and anterior cruciate ligaments

cross over one another, stabilizing the knee joint, preventing unwanted movements, and locking the knee when you stand

fibular and tibial collateral ligaments

aka lateral collateral ligament and medical collateral ligament

-prevent hyperextension and lateral and medial movement at the knee

What are the 3 broad ligaments that run from the patella to the tibia?

patellar ligament, medial patellar retinaculum, lateral patellar retinaculum

pivot joints

formed when the round end of one bone fits into a ring formed by another bone and an encircling ligament

-uniaxial movement along the vertical axis

-radioulnar joint

-supination and pronation

condyloid joints

knuckle-like joints in which the rounded end of one bone fits into an oval-shaped depression in another bone

-metacarpophalangeal joints

-abduction, adduction, circumduction

saddle joints

made up of two saddle-shaped articular surfaces with convex and concave areas

-biaxial movement

-sternoclavicular joint and the carpometacarpal joint which allows for opposition

sternoclavicular joint

Articulation between the clavicular facet of the manubrium of the sternum and the medial surface of the clavicle

-cavity is divided by an articular disc and the joint is surrounded by 4 ligaments: anterior and posterior sternoclavicular, interclavicular, costoclavicular

-make the sternoclavicular joint very stable

sternoclavicular ligaments

connect the sternum to the clavicle

interclavicular ligaments

connect the 2 clavicles

costoclavicular ligament

connects the costal cartilages of the first rib to the clavicle