Anatomy Exam 2

What are the functions of cartilage and bone (movements)

1. aBDuction

2. aDDuction

3. rotation

4. lateral rotation

5. medial rotation

6. flexion

7. circumduction

8. extension

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Cartilage and bone are a type of _______ tissue “________” type

connective

supportive

For cartilage and bone the tissue is _________

stiff/not compliant

Fibroblast like cells in terms of secretion of matrix include:

1. collagens

2. water binding GAG and proteoglycans (for cartilage matrix)

3. Calcium phosphate binding proteins (for bone matrix)

Cartilage and bone are unique (mostly) to ___________

chordate animals (allows chordates to migrate onto land)

What are the 7 functions of cartilage?

1. Template for axial and appendicular skeleton during embryonic development

2. growth of axial and appendicular skeleton during post-natal development

3. smooth articular surfaces for joints

4. shock absorber/cushion at joints

5. somewhat pliable junctions between some bones

6. support for tubes in the respiratory system

7. ear, nose, and epiglottis shape

What are the 7 bone functions?

1. protection of CNS and pleural cavity organs

2. support of the body and soft organs

3. levers for skeletal muscle action

4. site of blood cell formation in red bone marrow

5. triglyceride storage in yellow bone marrow

6. reserve of dietary (Ca2+, PO4, K+, Mg2+, F-, and some micro-minerals) and mineral homeostasis

7. Endocrine organs

   -secretion of osteoblasts

   -osteocalcin > glucose homeostasis, male fertility, exercise capacity

   -Phosphatonin (FGF23) > phosphate homeostasis

For cartilage and bone embryogenesis, the first to develop is the ____________ which provides __________

notochord derived from the mesoderm

structural support/protection for developing nerve tube

In cartilage and bone embryogenesis what is derived from the mesoderm and neural crest cells

1. Mesenchymal cells > progenitor > blasts > cytes

   -chondroblasts and osteoblasts

2. Condensation of mesenchymal cells differentiate to chondroblast then produce matrix

   -chondrogenesis

3. Neural crest cells differentiate into connective tissue cells of the head

For cartilage and bone embryogenesis axial and appendicular skeleton develop mostly from ______

somites

Somites differentiate into three regions (outer to inner) what are they?

1. dermotome > skin

2. Myotome > skeletal muscles

3. Sclerotome > cartilage and bone

The spine develops _____ to the ________. What does this include?

dorsal

notochord sclertome

Early notochord functions as a hydrostatic skeleton (develop turgor pressure like plants)

Notochord develops into intervertebral discs

Vertebra

Limbs develop as a cluster of cells giving a _________. This includes….

cartilaginous limb bud

joints form later (segmentation)

Skeletal muscle progenitors migrate into _______ and begin _______

limb bud

myogenesis

Fibroblast migrate in as well forming ______ and eventually ___________

tendons

separate anatomical muscles

Synergistic interactions between ____________ form functional appendage

cartilage, bone, tendons, and muscle

Long bone develops mostly from a _________. This all includes: ____________

cartilage template

1. endochondral bone formation

2. starts in the center of the long bone and works towards the ends

3. continues through embryonic, fetal, and post-natal growth

4. mostly stops at puberty

5. ends of long bone remain as cartilage (forms articular cartilage)

Flat bones develop mostly ____________. This all includes: ___________

de-novo from a cluster of cells

1. intramembranous bone formation

2. islands of bone fuse together to form a plate of bone

3. Plates may be joined by cartilage

4. eventually fuse to form contiguous “flat” bone

List the components of fibroblasts

1. line the outermost surface of cartilage and bone and produce dense regular connective tissue capsule

2. cartilage = perichondrium

3. bone = periosteum

4. may be multiple layers of cells

Cartilage and bone cells develop from ___________ cells. This means they can ___________

osteochondroprogenitor

differentiate into cartilage cells or bone cells (cartilage cells can trans-differentiate into bone cells)

The major cell type on the surface of the matrix are _______. List the components of this.

blasts

cartilage = chondroblasts (mostly flat squamous cell)

bone = osteoblasts (squamous to columnar cell depending on activity) the more columnar they are, the more active they are. They are epithelial-like, with a simple layer of polarized cells that secretes components on the bone side.

Linked by tight and adhesive junctions

communicate via gap junctions

The major cell type within the matrix are called _________. List the components of this.

cytes

1. location within the matrix (space occupied by cell) called lacunae

2. Cartilage = chondrocytes (round/cuboidal cell & can be active in secretion during growth)

3. Bone = osteocytes (almond-shaped cells, not active in secretion, and involved in maintenance/sensing/signaling in the bone)

Chondroblasts and chondrocyte matrix give a _________ pliable matrix. List the components of this.

gelatinous like

1. Fibers (college based made of collagen herterofibrils with various levels of aggregation and orientation, mostly collagen type II as fiber former)

   -Elastin

2. Ground substance (filler)

   -GAGs —> hyaluronan, chondroitin sulfate and keratan sulfate

   -Proteoglycan core proteins —> aggrecan and many others

   -multi adhesive glycoproteins link matrix components and cells together

3. Tissue fluid binds to GAGs/SO4- and COO-

4. Cartilage matrix 60-80% (wt/wt) water are moderately tightly bound and calcium phosphate crystallization is not highly favored

Osteoblasts secrete matrix products to make ________. List the components of this.

bone

1. fibers (collagen-based and can become organized into layers called orthogonal)

2. Filler

   -GAGs —> no hyalouronan but chondroitin sulfate and karatan sulfate

   -Proteoglycan core proteins —> decorin

   -Multiadhesive glycoproteins —> sialoproteins (osteopontin), osteonectin, and osteocalcin involved in calcification

3. Calcium-binding protein function

   -sialoprotein is the most abundance non-collagen protein of bone, are highly acidic protein rich (22%) in glutamic acid residues and binds to and nucleates hydroxyapatite crystal formation.

   -binds calcium and modulates calcification

   -bone Gla protein/osteocalcin (Gla= gamma-carboxyglytamic acid amino acid that binds calcium) Inhibits/regulates crystal formation but does not induce it. Decarboxylated and released upon bone remolding and used as a biomarker. Appears to have endocrine function on several organs

4. Mineral- mostly hydroxyapatite (HAP)

5. Bone matrix is 70-80% mineral

Cells that degrade bone are called ________. List the components of this.

clasts

1. osteoclasts

2. monocyte derived

3. multinucleate large cell with eosinophilic cytoplasm

4. polarized cell which seals off zone of bone by cell-substrate adhesions (sealing zones). They have ruffled membranes on bone side to increase surface area. Secretes acid and proteases into sealed chamber to degrade bone. Depression caused by degradation called Howship’s lacunae

5. Allows for remodeling bone to form mature (lamellar) bone

Cartilage tissue is contained within a ___________ capsule. List the components of this.

connective tissue

1. Cartilage —> perichondrium

2. articular joints —> joint capsule and synovial fluid

Within cartilage tissue, there are visco-elastic mechanical properties. List the components of this.

1. deformed via mechanical stress (visco)

2. returns to original shape upon removal of stress (elastic)

3. Mechanical properties result from matrix properties

4. Fibril/fiber organization dependent upon type of cartilage and location within a type

5. GAG and proteoglycans binding water (hydration)

Within cartilage tissue, there is something called avascular and aneural. List the components of this.

1. nutrition by diffusion from surrounding tissues > mostly glycolytic (anaerobic) metabolism

2. activity stimulates diffusion > stress favors liquid movement

3. repair limited to nonexistent in the adult —> limited exposure to growth factors and nutrients

4. pain via damage sensed by nerves in bone or joints not within cartilage

Within cartilage tissue there are three different types based upon matrix fibril/fiber types and organization. What are they and what are there components.

1. Hyaline

   -”classic cartilage” or main type

   -mostly collagen type II heterofibrils

   -Template for long bones and ends of mature bones

   -support for respiratory tubes (trachea & bronchi)

2. Elastic cartilage

   -contains elastin fibers in addition to collagen type II heterofibrils

   -enrichment in elastin allows for more “elastic” than visco-elastic mechanical properties

   -found in the epiglottis, external ear, ear canal, and eustachian tube

3. Fibrocartilage

   -contains collagen type I and II heterofibils

   -collagen type I forms visible fibers in the matrix

   -chondrocytes lined up in rows between collagen fibers

   -more fibrous than amorphous matrix

   -hyaline cartilage like matrix deposited between the collagen type I fibers

   -found where both resistance to shear and compression is required (shock absorber properties)

   -anatomical locations are articular/joints discs of the intervertebral, temporomandibular, sternoclavicular, and knee joint

What are the components of hyaline cartilage growth

1. chondroblasts produce matrix and encase themselves within it

   -form lacunae (spaces)

   -cell called chondrocyte when encased

2. chondroctes can divide within their lacunae

   -cells within the same lacunae are called isoenous groups

3. growth of cartilage island can be appositional or interstitial

   -apposition growth on the surface and interstitial within (long bone growth mostly mediated by interstitial growth)

4. Growth occurs mostly by adding more matrix than cells

5. Growth regulated by hormones and stimulated by mechanical activity

   -growth hormone —> insulin-like growth factor stimulates growth

   -androgens stimulate growth

   -corticosteroids inhibit growth

6. becomes calcified with increasing age

Bone tissue is contained within a fibrous collagen capsule called ________

periosteum

bone tissue is vascularized and innervated. This means __________

the matrix itself is sealed off from blood via surface osteoblasts (form tight junctions to form sealed environment)

Bone tissue have still mechanical properties, this means:

they are very small strain relative to stress (microstrain levels upon large stress)

In bone tissue matrix components favor calcium-phosphate crystal formation making it still. What does this include

Hydroxyapatite (HAP) the more HAP the more brittle

In bone tissue collagen fibers are organized in mature bone to add additional strength. What does this include

orthogonal (plywood like) layers

decorin-mediated spacing of fibr

Classification of bone tissue is based upon ______________

macroscopic shape, density, and maturity

List the components of classifying the shape of bone tissue

1. long

   -many appendicular bones

   -structures include epiphysis (epiphyseal line/plate), metaphysis, and diaphysis (cortical bone, medullary (marrow) cavity)

2. Short

   -cube shaped bone in the ankle and wrist

   -sesamoid bones within tendons (patellar bone)

3. flat

   -mostly axial bones

   -cranial bones, scapula, sternum, and ribs

4. irregular

   -many axial bones

   -vertebra, os coxa, some cranial bones

List the components of classifying density of bone tissue

1. compact

   -walls of long bones, plates of flat bones

   -contains blood vessels and nerve

2. spongy/cancellous/trabecular

   -spicules of bone that interconnect

   -medullary compartment of many bones

   -adds support/strength

   -surrounded by connective tissue cells (blood or fat cells)

List the components of classifying maturity of bone tissue

1. newly formed bone has unorganized collagen fiber orientation called immature bone

2. remodeled bone has collagen fibers organized in layers called mature bone

3. immature = woven & mature = lamellar

What are the two main groups of skeletal bones and what do they include

1. Axial —> skull, vertebrae, ribs, and sternum

2. appendicular —> limbs and girdles

Bones have markings/landmarks for function, list the components

1. opening for vessels and nerve —> foramen

2. depression or groove for organ or vessels and nerve —> fossa

3. elevation or bump for tendinous or ligament attachment

   -large —> trochanter

   -intermediate —> tuberosity

   -small —> tubercle

4. edge of a flat bone —> margin

5. enlargement at the end of a large bone covered with cartilage at a joint —> head

6. flat smooth surface at a plane type joint —> facet

Articulations (joints) are defined as ___________. What are the components of this?

the junction between two or more bones

1. named bones formed during embryogenesis (ox coxa- hip bone forms three bone islands fused together

2. joint may be calcified or highly mobile

What are the functions of articulations (joints)

1. allow for mobility between bones

2. links bones in the skeleton

3. allows for growth of skull bones (chambers) and other flat bones

Joints can form between long, short, flat, or irregular bones during _____________.

embryonic development (skeletogenesis)

Long bones form from a ___________ > cartilage template. List the components of this

mesenchymal cluster of cells

1. starts as a complete appendage of mesenchyme then segments at future joints (example of upper appendage development)

Flat bones grow and meet at _______ then joined by cartilage and eventually _________. Example of cranium sutures

junctions

calcifies

There are two general types of joint classifications with relationships between the two. What are they?

Functional —> amount and type of movement allowed.

Structural —> connective tissue type that joins the bone and presence or absence of space between bones

List the components of functional joint types

1. synarthroses —> immovable joint as in between cranial bones

2. amphiarthroses —> slightly moveable as in pubic symphysis between pelvic bones

3. Diarthroses —> highly moveable joint as in the hip joint

List the fibrous components of structural joint types

1. Fibrous —> joined by dense fibrous connective tissue and lack a joint cavity

   -most are synarthrosis

   -fibrous further grouped based upon the length of connective tissue fibers

   -sutures —> short fibers connect the bones, eventually calcify, giving synostoses

   -syndesmoses —> broad sheet of longer fibers forming interosseous membranes > join bones of the distal appendicular skeleton (forearm and leg)

   -Gomphoses —> short fibers that link teeth into their socket in the jaw bones (periodontal ligament)

Lis the cartilaginous components of structural joint types

1. Cartilaginous (synchondroses) —> joined by cartilage (hyaline or fibrocartilage) and lack joint cavity

   -most are amphiathroses

   -cartilaginous further grouped based upon the type of cartilage

   -synchondroses —> joined by hyaline cartilage that may become calcified (epiphyseal plate and costal cartilage)

   -symphyses —> fibrocartilage joins the bone, mostly uncalcified (intervertebral joint, pubic symphysis)

List the components of synovial joints

Bones separated by a cavity that is fluid-filled, and highly moveable. ALL are diarthrotic

What are the components and features of synovial joints

1. articular cartilage —> lines the ends of the bones

   -compressible/compliant, so functions as a shock absorber

   -action at the joint stimulates maintenance of the cartilage

2. a joint cavity —> space between bones filled with a viscous fluid

3. joint capsule —> made of two layers and encloses the joint cavity

   -outer layer made of dense irregular connective tissue for strength

   -inner layer that forms a secretory membrane via synoviocytes (secrete synovial fluid)

4. synovial fluid —> lubricating fluid within the joint cavity

   -plasma ultrafiltrate enriched in hyaluronan and lubricin that lubricates the articular cartilage

   -contains phagocytic cells to remove foreign material and bacteria

5. ligaments —> dense regular connective tissue that re-enforces the joint capsule and joint

   -three locations- capsular, extracapsular, intracapsular (within the joint, cruciate ligaments of the knee and ligamentum teres of the hip)

6. nerves and blood vessels —> sensory receptors and nourish the joint

   -articular cartilage is avascular and aneural so fed via diffusion and pain via receptors in the capsule

Other synovial joint structures for lubrication and cushioning of the joint and tendons that cross over the joint include what?

1) Fat pads > cushioning between the fibrous layers and synovial membrane or bone

2)Articular discs (menisci) > fibrocartilage that separates the articular surface for stabilizing the joint structure > knee joint

3) Bursa > sacs lined internally by synoviocytes that contains synovial fluid that reduces friction

-Located where ligaments, muscles, skin, tendons, or bones rub together

4) Tendon sheath > like bursa but wraps around a tendon  

Factors that stabilize the joint:

1) Joint capsule and anatomy > lowest contribution

2) Ligaments > intermediate contribution

3) Muscle tone > most contribution with agonist and antagonist being active simultaneously

-MUSCULOSKELETAL system as an organ system

Major synovial joints are:

1) Temporomandibular

2) Shoulder (glenohumeral)

3) Elbow

4) Hip

5) Knee

6) Wrist

7) Ankle

8)Digits

Movements allowed by synovial joints include

1) Movement involves shortening of the muscle that crosses over the joint

-Two main points of attachment of the muscle tendon to bone

-Origin > bone that does not move

-Insertion > bone that does move

-Mostly changes the angle of the joint (increase or decrease)

2) Movement of structures occurs in three anatomical planes

-Transverse > rotations

-Frontal/coronal > abduction, adduction

-Sagittal > flexion and extension 

Types of axial (at a stationary point) movements at a joint include

1) Non-axial  

-Planar joints that allow gliding movement 

-Wrist and ankle bone joints

2) Uni-axial 

-Hinge or pivot joints that allow movement in one plane

-Elbow, knee, forearm, leg

3) Bi-axial 

-Condylar and saddle joints that allow movement in two planes 

-Digits

4) Multi-axial 

-Ball and socket joints that allow movement in all three planes

-Should and hip

What are the three types of general movements about a join

1) Angular

-Movement that increases of decreases the angle between the bones at a uni-axial, bi-axial, or multiaxial joint in one anatomical plane 

-Flexion or extension in the sagittal plane

-Flexion decreases the angle

-Extension increases the angle

-Adduction or abduction in the frontal plane

-Adduction decreases the angle

-Abduction increases the angle

-Circumduction in both planes

-Flexion, extension, adduction, and abduction giving movement of the limb in a cone in space 

2) Rotational

-Turing movement along the long axis (inferior/superior) at uni-axial and multi-axial joints

-Medial rotation towards the midline 

-Lateral rotation away from the midline

3) Gliding

-Movement between flat bone surfaces at a non-axial joint

-Intercarpal (wrist), intertarsal (ankle), and intervertebral joints

clinical correlates can be divided into acute and chronic conditions, what does each result from

1. acute results from excessive mechanical strain/stress on joints that will repair itself

2. chronic results from genetics and environmental/repeated stress/strain on joint that will NOT repair itself

List the components of acute damage

1) Sprains > hyperextension or excessive strain on ligaments

-Slow to repair, can use surgery or cadaver tissue as source of ligament

2) Dislocations > articular surfaces forced out of alignment by excessive strain on joint

-Repair by re-alignment (reduction)

-Cartilage tears > damage (fissures, de-lamination, or fragmentation) of articular cartilage

-May or may not repair naturally because of poor regenerative capacity of hyaline cartilage

What are the most disabling categories of disorders

1) Disorders of the back

-Chronic back pain

2) Osteoarthritis

-Wrist and hand

-Hip

-Knee

3) Other arthropathies

-Rheumatoid arthritis

-Psoriatic arthritis

Name the features of osteoarthritis

1. Pain and degeneration at appendicular synovial joints

2. Loss/thinning of cartilage at the epiphyses of joint bones 

3. Joints most affected:

   -Manus digits

   -Carpals and metacarpals

   -Wrist

   -Knees

   -Hips

4. In late stages, causes dysmorphia of appendage at the joint via osteophytes (bone growth in and around joint cavity)

5. Usually asymmetrical (R or L side joint)

List the causes of osteoarthritis

1. Age (usually > 50yo)

2. Obesity

3. Repeated abuse of joint

4. Injury to joint

5. Genetic defects in cartilage development and maintenance

List the features of rheumatoid arthritis

1. Pain and degeneration at appendicular synovial joints associated/caused by inflammation

   -An autoimmune disease

2. Damage to articular cartilage at the joints similar to osteoarthritis

3. Joints most affected similar to osteoarthritis but symmetrical

4. May also have other autoimmune diseases such as Lupus

List the causes of rheumatoid arthritis

1. Smoking

2. Age (usually > 30 yo)

3. Genetics

   -Biological sex and other genes

In skeletogenesis formation of the skeleton is from ___________, which includes __________

mostly mesoderm derived cells

cartilage, bone, and joint formation

Undifferentiated cells of the mesoderm and neural crest differentiate into _________. This includes what?

skeleton-producing cells

1) Para-axial mesoderm > mostly the axial skeleton

2) Intermediate mesoderm > mostly appendicular skeleton and some craniofacial

3)Neural crest > craniofacial and neck skeleton

Skeletogenic (chondrogenic and osteogenic) cells proliferate at future sites of the skeleton then differentiate and ____________. This includes

secree m

Name the components of skeletal ontogeny (developmental sequence)

1) Primary skeleton forms the skeletal template for subsequent growth

-Axial

-Appendicular

2) Flat bones

3) Secondary (re-modeled cartilage template) growth continues into early adulthood

-Conversion of cartilage to bone

4) Growth of flat bones to accommodate increase in brain size

5) Bone remodeling occurs through-out life to accommodate repair and response to the environment (mechanical and nutritional) 

List the components of De-novo bone formation

1)  Occurs between two “membranes” of undifferentiated mesoderm

2) Does not use/need template

3) Cells between membrane differentiate into groups of osteoblasts and secrete matrix

4) Matrix spontaneously calcifies in and around cells to form islands (spicule/trabecula) of bone

-Cells become trapped within > osteocytes

-Cells on surface > osteoblasts

5) Islands grow and fuse eventually forming two flat surfaces with spongy/trabecular bone in between

6)Used to form many of the cranial bones and the bone collar of long bones

Endochondral ossification has a conversation of cartilage matrix and cells into _________. What are the components of this

bone matrix and cells

1. except at the ends of bones forming cartilaginous and synovial joints

2. forms most of the bones of the body (ALL appendicular skeleton and MOST of the axial skeleton)

What does endochondral ossification involve

complex signaling pathways that regulate poliferation (number of cell), differentiation (being secreting matrix) and growth then invasion/differentiation of bone forming cells to convert template to bone.

Endochondral ossification involces signaling pathways that regulate proloferation differentiation, what does this include?

1) Begins as mesenchymal (mesoderm) compaction at future bone then cells differentiate and begin secreting matrix making the cartilage template

2) Formation of bone collar at diaphysis midpoint of template

-Transformation of perichondrial or undifferentiated cells into osteoblasts

-Intramembranous bone formation on the surface of the cartilage

-Develops into compact bone

3) Hypertrophy of diaphysis medullary chondrocytes

4) Calcification of matrix around hypertrophied chondrocytes

5) Death or re-differentiation of chondrocytes in calcified cartilage 

6) Osteoclasts perforate bone collar followed by invasion of vasculature and osteoprogenitor cells at center of diaphysis

7) Ossification of calcified cartilage template

8)Formation of marrow cavity

In endochondral ossification involves growth in length involves calcification front chasing growing cartilage at the ends (epiphyseal growth plate) giving different zones of developing supportive connective tissue. What does this involve?

1) Resting or reserve cartilage

-Small cells, generally 1/lacunae

2) Proliferation

-Smallish cells, many cells/lacunae, aligned along the long axis of bone

3) Hypertrophy

-Large cells, many cells/lacunae, aligned along the long axis of bone 

4) Calcification

-Chondrocytes secrete matrix vesicles

-HAP crystalizes in matrix to form spicules

-Chondrocytes lost via apoptosis, autophagy, or transdifferentiate into osteoblast

5) Ossification

-Osteoblasts form immature bone on calcified cartilage

secondary ossification center forms in the ________________

proximal epiphysis and recapitulates the zone

long bone growth stops when ________________

epiphyseal plate cartilage growth terminates (epiphyseal plate closure)

Bone growth and homeostasis involves complex ________ signaling during embryonic development

morphogen

in bone growth and homeostasis, post-natal growth involves hormones that regulate ___________ levels and stimulate or inhibit primarily hyaline cartilage growth

calcium and phosphorous

In bone growth and homeostasis regulation of blood calcium and phosphorous include

Calcium homeostasis involves hormones that target intestinal absorption, kidney excretion and bone

1. Parathyroid hormone > increases blood calcium by removing it from bone, increasing intestinal absorption, and decreasing kidney excretion (directly or indirectly)

2. Calcitriol (active form of vitamin D) > increases blood calcium by removing it from bone, increasing intestinal absorption, and decreasing kidney excretion

-PTH and calcitriol work together for their effects on blood calcium

3. Calcitonin > “tones” down blood calcium by directing it into bone, decreasing absorption, and increasing excretion although its function in humans is unclear

Phosphorous homeostasis involves calcitriol and phosphatonin (FGF23)

1. Calcitriol > increases blood phosphate via increasing release from bone and intestinal absorption

2.  Phosphatonin (via bone) > decreases blood phosphate by increasing phosphate excretion and decreasing calcitriol synthesis

Blood calcium and to some extent phosphorous are tightly regulated

1. Calcium 8.5 – 10.2 mg/dL

2. Phosphorous 2.8 – 4.5 mg/dL

3. Excess of blood calcium and phosphorous can result in “ectopic ossification” of tissue

Hyaline cartilage growth is regulated by several hormones, name the components.

1) Growth hormone/insulin-like growth factor > stimulates growth

2) Estrogen and testosterone > stimulates growth at low levels then favors epiphysial plate closure at puberty

3) Thyroid hormone > required for other hormones to stimulate growth

4) Cortisol > inhibits bone growth/maintenance in excess 

Bone is dynamically remodeled upon changes in blood calcium, mechanical stress/strain and micro fractures. What are the components?

1) Low blood calcium (dietary or otherwise) results in bone loss mediated by hormones

-Will rebuild if blood calcium levels returned to normal

2) Mechanical stress/strain from gravity and/or muscle activity affects bone remodeling

-Increase stress/strain > increase bone thickness/growth

-Bone markings associated with origins and insertions

-Decrease stress/strain > decrease bone thickness/growth

-Major issue for space flight

-Orthodontic devises result in remodeling of the tooth socket (not the tooth)

3) Microscopic breaks (stress fractures) in bone are repaired to prevent catastrophic bone fracture 

Bone remodeling and repair involves coordinated activity of osteoclasts followed by osteoblasts and osteocytes. List the components

1) Osteoclast bore a hole/cylinder through the bone at the “cutting zone”

2) Osteoblast follow the osteoclast and fill in with new bone matrix – layer upon layer

3) Some osteoblasts get trapped and form osteocytes

4) End result is a new osteon (concentric circles of bone matrix) 

5) Continual process to repair/remodel bone during your lifetime

growth of flat bones of the the skull involves ____________

removing deep bone and adding superficial bone

List the components of a fracture repair

1) Recapitulates (somewhat) intramembranous and endochondral bone formation

2) Can be divided into different phases and sub-phases

3) Reactive phase

-Rupture of blood vessels > blood clot > homatoma

-Stimulate fibroblast proliferation and secretion of matrix material

-Soft granulation tissue (dense irregular connective tissue)

4) Reparative phase

-Periosteal cells stimulate to proliferate and differentiate at wound site

-Chondroblasts > hyaline cartilage

-Fibroblast > collagen fibers

• Both give fibro-cartilage like matrix called a soft callus

-Endochondral ossification begins to harden the callus

-Angiogenesis into the callus brings in osteoblast and osteoclast

-Osteoblast > calcification/woven trabecular bone 

• Further hardens callus

-Osteoclasts remodel woven bone into lamellar bone

-Surface bone remodeled from trabecular to compact bone 

What are the functions of nervous system

1. The communication and processing hub of the body

   -Communication is via electrical action potentials (frequency of) allowing for rapid response > millisecond time scale or less

2. Senses the environment through receptors mostly in the peripheral nervous system and send to central nervous

   -Sensory afferent signals > to processing centers

   -Internal environment > enteroreceptors

   -External environment > exteroreceptors

3. Interprets sensory information in the central nervous system

   -Signal type

   -Signal strength (frequency)

   -Signal meaning

   -What to do about the signal > motor response

4. Sends out motor response to act upon the sensory information

   -Motor efferent

   -Action in response to sensory information and interpretation

5. Stores information > memory

6. Thinks > problem-solving!!!!

7. Develops emotional state and sense of being

List the components of development in the nervous system

1. Forms via invagination of ectoderm along the anterior – posterior axis just above the notochord

   -Cells form neuroectodermal plate

   -Plate of cells invaginates to form the nerve groove

   -Nerve groove folds into a tube and migrates below the ectoderm

   -Develops into the central nervous system and becomes encased within bone

   -Brain and spinal cord

2. Nerve fibers (axons) migrate out of the central nervous system and form synapses with sensory receptors and motors

3. Some nerve-like cells migrate from the nerve plate to the far reaches of the body and cells/structures involved in the peripheral nervous system

   -Neural crest cells > form some sensory structures, glial cells, and ganglia

   -Also develop into mesenchymal cells mostly in the head

4. Nerve cell division continues until about 20 yo then stops

   -Cells enter Go of the cell cycle and are not replaced

   -Somewhat resistant to cell death

   -Oldest cell in the body and accumulates debri affecting function > “Senior Moments”

   -Most last your lifetime so treat them nicely

The central nervous system (CNS) is encased/protected by bone. What does this entail

1. Within the dorsal body cavity

2. Mostly nerve tissue with a bit of vasculature and connective tissue

3. Specialized circulatory system for nutrition > cerebral spinal fluid is produced and flows through channels in the CNS

The peripheral nervous (PNS) is encased within connective tissue proper, what does this entail

1. Once nerve leaves the CNS it is peripheral nerve 

2. It is found in all cavities and regions of the body except the dorsal cavity

3. Includes connective tissue and vasculature within the peripheral nerve

4. Organized as fibers macroscopically

5. Contains the processes (axons) of many cells

What do sensory divisions entail

1. Carries sensory information to the central nervous system for processing and interpretation

2. Afferents

What do motor divisions entail

1. Carries information to muscles (all types) and glands for action

2. Efferents

3. Muscles > shortening

4. Glands > secretion

What does the somatic division entail?

1. From somite > clusters of cells along the developing nerve tube that give rise to the musculoskeletal system and skin

2. Under conscious control via the central nervous system

3. Includes sensory nerves in skin and musculoskeletal system

4. Includes motor nerves in skin and musculoskeletal system

5. Skeletal muscles > move

6. Sweat glands > secrete

What does the autonomic division entail?

1. You do not have to “think” about it, occurs automatically

2. Sensory processing and control mainly by the hypothalamus and brain stem of CNS

3. Controls organs within the oral and abdominopelvic cavities - visceral organs

4. Includes sensory nerves in cardiovascular system and organs

5. Includes motor nerves to cardiac and smooth muscle and endocrine/exocrine glands

the nervous system functions as a _____________ much like a homeostatic system

control system

what does the patellar tendon stretch response entail

1. Stimulus > stretch tendon

2. Receptor > muscle spindles (proprioreceptors) detect change in muscle length

3. Integration in the spinal cord (CNS) of muscle is too long and need to shorten

4. Effector > rectus femoris activated to shorten back to original length

5. Response > return to desired length

Neurons and glia (neuroglia) neuroglia are the main cell types present within the nervous system. What does this entail?

1) Some stroma via fibroblast but much lower than most other organ systems

2) Neurons are the electrically active cells (action potential)

3) Neuroglia/glia are support cells involved in protection, myelination, and nutrition of neurons

Neurons are cells with long processes and three parts, what are they?

1) Dendritic process > carries information to the cell body

-One or more per cell body

2) Cell body > interprets information from dendrites (membrane voltage) and sends out information if stimulus is sufficient

-Large, round, and large euchromatic nucleus with prominent nucleolus

3) Axon process > carries information to the target tissue (another nerve or a motor)

-One per cell body but can branch near its end

Neuron types are classed by structure and function, what are they.

1) Multipolar > more than two processes per cell

-Two or more dendrites and one axon

-Can receive information from numerous nerves via its dendrites

-Inhibitory signals from other neurons

-Function as motor neurons and interneurons

-Interneurons connect sensory > processing > motor neurons in the CNS

-Most neurons in the system are multipolar 

2) Bipolar > two processes

-One dendrite and one axon

-Function as sensory nerves in the retina (eye), nose (smell), vestibulocholear system (hearing and balance), and tongue (taste)

3) Unipolar > one process

-Process functions as a dendrite at one end and an axon at the other (fused dendrite and axon)

-Function as the major sensory neuron other than special senses given for bipolar neurons

-Pain, tactile, pressure, and chemical receptors