BIO 203 Exam 2 (L7-11)

what does the skeletal system include

bones, cartilage, and ligaments

how does the skeletal system protect internal organs

skull → brain and rib cage → heart and lungs

what are the functions of the skeletal system

protect internal organs, mineral storage, and movement

what minerals does the skeletal system store

calcium and phophate

how does the skeletal system promote movement

bones act as levers and joints act as pivots, the muscles pull on the bones through muscle contraction to create movement at joints

explain compression

squeezing/pushing

explain tension

pulling/stretching

where is hyaline (most common) cartilage found

articular surfaces of joints = articular cartilage, nose, costal cartilage (ribs), trachea & bronchi

where is elastic (most flexible) tissue found

external ear and epiglottis

where is fibrocartilage (strongest) cartilage found

intervertebral discs and menisci of the knee

what is hyaline cartilage best suited for

compression

what is elastic cartilage best suited for

flexible bending

what is fibrocartilage best suited for

compression and tension

structure of hyaline cartilage

fine type II collagen fibers; smooth matrix

structure of elastic cartilage

rich in elastic fibers

structure of fibrocartilage

thick bundles of collagen fibers

function of hyaline cartilage

support and smooth, low-friction surfaces at joints

function of elastic cartilage

flexible support; bends and returns to its original shape

function of fibrocartilage

resists compression and absorbs shock

explain how the structure of hyaline cartilage helps it function

water-rich matrix and proteoglycans help it resist squeezing

explain how the structure of elastic cartilage helps it function

elastic fibers allow it to bend and return to shape

explain how the structure of fibrocartilage helps it function

abundant type I collagen gives strong resistance to pulling/stretching, while its cartilage matrix also handles compression

chondroblasts

produces cartilage matrix and mature into chondrocytes

chondrocytes

maintain the cartilage matrix and occupy small spaces called lacunae

annulus fibrosus

strong outer fibrocartilaginous ring that surrounds the nucleus pulposus

function of annulus fibrosus

resist tension and helps distribute the load

nucleus pulposus

gel-like central core rich in water and proteoglycans (not cartilage)

function of nucleus pulposus

main-structure that absorbs copression/shock

fibrocartilage

they experience substantial compression from body weight and tensile forces as they spread that load across the knee

hyaline cartilage endplates

separate the disc from the adjacent vertebral bodies

function of hyaline cartilage endplates

help support the disk and distribute load

articular (hyaline) cartilage

covers the end of articulating bones, provides a smooth, low-friction surface, and reduces wear during movement

menisci

absorbs shock and distributes forces across the knee joint

meniscus tears

injury to the cartilage between the femur and tibia, which can occur from twisting or turning quickly, often with the foot planted while the knee is bent

what is included in the longitudinal axis (axial skeleton) of the body

skull, vertebral column, thoracic cage

main role of axial skeleton

support and protection

what is included in the appendicular skeleton

pectoral girdles, upper limbs, pelvic girdle, and lower limbs

main role of appendicular skeleton

movement and locomotion

what is the skull made up of

22 bones: 8 cranial and 14 facial

describe the 8 cranial bones

they protect the brain: parietal (2), temporal (2), frontal, occipital, ethmoid, sphenoid

what joins skull bones

sutures

describe the 14 facial bones

provide openings for the respiratory and digestive passages and attachment points for facial muscles

what does the rib cage do

protects the heart and lungs and supports the thorax

what is included in the rib cage

12 pairs of ribs: 7 pairs true ribs, 5 pairs false ribs (last 2 pairs are floating), sternum, thoracic vertebrae (posteriorly)

what does the vertebral column do

houses the spinal chord, supports the head and trunk, protects the spinal chord, and forms the central supporting axis of the body

what is included in upper limbs

bones of the arm, forearm, hand

what is included in lower limbs

bones of the thigh, leg, foot

the pelvic floor

made up of thick skeletal muscles, helps support the visceral contents of the pelvis

kegal exercises

strengthen muscles of the pelvic floor

what does the pelvic girdle do

connects the lower limbs to the axial skeleton and supports body weight

what does each hip bone consist of

ilium, pubis, and ischium

what makes up the pelvic girdle

formed by the two hip (coxal) bones

what does the pectoral girdle include

clavicle and scapula

what does the pectoral girdle do

connects the upper limbs to the axial skeleton

Q angle

the angle that describes the alignment of the hip, patella, and tibia and the direction of quadriceps pull on the knee

traits of the female skeleton

smaller, less robust bones, less prominent brow ridges and muscle markings, smaller, less robust mandible

traits of the male skeleton

larger, more robust bones, more prominent brow ridges and muscle markings, larger, more robust mandible

traits of the female pelvis

wider and shallower, more rounded pelvic inlet, wider subpubic angle, more flared iliac blades

traits of the male pelvis

narrower and deeper, more heart-shaped pelvic inlet, narrower subpubic angle, less flared iliac blades

shape of flat bones

thin, flattened, often slightly curved

function of flat bones

protect internal organs, provide broad surfaces for muscles attachment

example of flat bones

skull and sternum

shape of irregular bones

complex shapes that do not fit other categories

function of irregular bones

provide support and protection, provide multiple sites for muscle attachment

example of irregular bones

vertebra and pelvis

shape of long bones

longer than they are wide; have a shaft and two ends

function of long bones

act as levers for movement, many also help support body weight

example of long bones

femur

shape of sesamoid bones

small, rounded bones embedded within tendons

function of sesamoid bones

reduce friction and stress on tendons, can improve mechanical leverage

examples of sesamoid bones

patella and pisiforme

shape of short bones

roughly cube-shaped

function of short bones

provide stability, allow limited movement, and help distribute forces

examples of short bones

carpus and tarsus

what is the organic component of a bone

osteoid, type 1 collagen fiber, ground substance & matrix proteins

what is the inorganic component of a bone

bone mineral, calcium phosphate, primarily hydroxyapatite crystals

medullary cavity

hollow cavity within the diaphysis, contains mostly yellow bone marrow in adults

compact bone

dense bone forming over the outer wall; thickest in the diaphysis

spongy (trabecular) bone

network of trabeculae found mainly within the epiphyses

what may be found in the spaces between trabeculae

red bone marrow

red bone marrow

site of blood cell production (hematopoiesis)

yellow bone marrow

rich in adipocytes; stores energy as fat

epiphyseal (growth) plate of a long bone

hyaline cartilage where longitudinal bone growth occurs in children and adolescents

epiphyseal line of a long bone

ossified remnant of the growth plate in adults, line represents the epiphyseal plate being closed

epiphyses of a long bone

expanded ends of the bones

diaphysis of a long bone

shaft of the long bone

metaphysis of a long bone

transition region between the diaphysis and each epiphysis

what are the coverings of a long bone

endosteum, periosteum, articular cartilage

endosteum

thin cellular membrane lining the medullary cavity and internal bone surfaces

periosteum

tough connective tissue membrane covering the outer bone surface

articular cartilage

hyaline cartilage covering the joint surfaces of the epiphyses

what are the major cell types of bone

osteoclasts, bone-lining cells, osteoblasts, osteocytes

osteon

made of concentric rings of bone matrix called lamellae, embedded within the bone matrix are osteocytes, sitting in small spaces called lacunae and communicate through tiny channels (canaliculi)

hydroxyapatite

deposited along and between the collagen fibers

collagen fibers

run in different directions in adjacent lamellae, helping bone resist twisting and crack propagation

hydroxyapatite crystals

Ca₁₀(PO₄)₆(OH)₂ calcium-containing mineral crystals (mainly calcium and phophate)

osteon (haversian system)

fundamental structural unit of compact bone

central (haversian) canal

runs through the center of an osteon and contains blood vessels and nerves

osteoclasts

CONSUME bone

• large, multinucleated cells

• responsible for bone resorption

• secretes acids and enzymes that dissolve bone matrix

bone-living cells

• flat, inactive cells covering bone surfaces

• derived from osteoblasts

• help regulate the bone surface and may become active during remodeling