Anatomy and Phy Exam 2 (chopped edition)

What is the structure and function of Compact Bone?

They’re arranged in osteons in the haversian/central canal;   Contains collagen fibers in different directions, giving strength to the bone to twist; less likely to break

What is the structure and function of Spongy Bone?

They’re poorly arranged in the trabeculae; Consists of the lamellae arranged in a lattice-like network; osteocytes are connected by lamellae

What is the function of osteoblast , where are they derived and whats there function?

the bone-creating cells; created by the osteoprogenitor cells; located in periosteum and endosteum, derived from osteogenic cells

What is the function of osteoclasts, where are they derived and whats there function?

   the bone-destroying cells; derived from osteoblasts and macrophages; located in resorption bays in the surface of bone and collagenase enzyme

What is an osteogenic cell?

an immature stem cell which gives rise to other bone cells

stem cells in bone that can differentiate into osteoblasts and osteocytes

stem cells in bone that can differentiate into osteoblasts and osteocytes

What a osetocytes?

   mature bone cells within lacunae/bony tissue; respond to stress and mechanical stimuli, allowing bone remodeling

How are osteoclast formed and why arew they multinucleated?

-       Osteoclasts are formed via the hematopoietic stem ells from the monocytes/macrophage line; they fuse under the influence of rankL. Theyre multinucleated because the fusion of the cells

What is Intramembranous ossification?

the bones are developing from the fibrous membrane; the mesenchymal cells differentiate in osteoblasts and secret osteoid, which hardens; it begins from the woven bone in immature bone

What is endochondral ossification?

replacing the hyaline cartilage; begins early on in the fetus when the skeleton is cartilage and forms most the skeleton

What affects the bone density?

Parathyroid Horomone & Gluccorticoid Steroid?

How does Parathyroid Hormone affect Bone density?

Increases expression of RANK Ligand (RANKL), which stimulates osteoclast formation and activity — leading to increased bone resorption (breakdown) and decreased bone density.

How does Gluccocortoid Steroid affect Bone density?

Decreases osteoprotegerin (OPG) and increases expression of RANKL on osteoblasts, which enhances osteoclast formation and activity, leading to increased bone resorption and decreased bone density

  What is osteocalcin and its mechanism of action

Osteocalcin is a vitamin K–dependent protein secreted by osteoblasts that binds calcium to the bone matrix and also acts as a hormone regulating metabolism and testosterone production

What is the periosteum and what are the different layers of the periosteum?

white double-layer membrane composed of dense, irregular CT; it contains osteogenic cells covering the surface of the bone; an anchoring point for tendons and ligaments

o   Outer Layer (Outer Fibrous Layer): made of dense, irregular CT, collagen fibers, nerves

What is the endosteum, and what are the different layers of the periosteum?

-       a delicate layer of ct covering the internal bone surface

o   contains the osteogenic cells and can differentiate into different types of bone-creating cells

What connects the periosteum to the bone?

Sharpey’s Fibers

What is meant by diploe?

• is the spongy (cancellous) bone layer found between two layers of compact bone in flat bones — especially in the skull.

What is osteoid, which cells secrete it, and what is it made up of?

Osteoid = unmineralized organic matrix made by osteoblasts, containing collagen + ground substance + proteins, which later becomes calcified with hydroxyapatite to form hardened bone.

 Why is it important for collagen fibers in compact bone to run in different directions in adjacent rings?

ts important for the collagen fibers in compact bone to run in different directions in adjacent rings because it aids in maintaining strength during twisting and bending forces.

1)    What are perforating canals and their function

Perforating canals are passageways that run perpendicular to osteons, connecting blood vessels and nerves from the periosteum to the central canals and marrow cavity, ensuring compact bone stays alive and nourished.

What is red mrrow?

produced blood cells ( red blood cells, white blood cells and platelets; red due to blood cells and mostly found in the bones of children in flat bones and proximal epiphyses;

What is yellow marrow

stores adipocytes (fat cells) for energy; contains adipose tissue and few blood vessels; yellow due to fat and not found in children; found in the mediastinal cavity

What is bone?

: rigid, highly vascular connective tissue that forms the skeletal framework; the cells are osteocytes, which are housed in the lacunae; supports movement, protection, and blood cell production

What is cartilage?

flexible avascular connective tissue typically found in the ears, ribs, and joints; the cells are chondrocytes housed in lacune; firms but flexible; provides flexibility and reduces the friction and acts a cushion

What is Appositional Growth?

the increase in bone thickness

What is Interstitial Growth

• bone longer (at the epiphyseal plate)

• Bone growth in length stops when the epiphyseal plate ossifies into the epiphyseal line (end of puberty).

Stages of Intestital Growth

 

1.    Resting/Reserve Phase (quiescent zone)

a.    Inactive cartilage on the epiphyseal side of the epiphyseal plate

2.    proliferation growth zone: division of the cartilage on the diaphysis side of the epiphyseal plate; rapidly divides, pushing epiphysis away from the diaphysis end (lengthening)

3.    Hypertrophic zone: full of chondrocytes, closest to the diaphysis are enlarged

4.    Classification zone: the cartilage and matrix has been layered and sided after it takes in the calcium, the chondrocytes die and deteriorate

5.    Ossification zone(osteogenic): chondrocytes are dead and capillaries and osteoblast from the diaphysis move into the zone

What are the features of flat bone?

two layers of compact bone with spongy bone in the middle

o   Lightweight but strong structure shielding the internal organs

o   Ribs, scapula, and skull bones

What is the structural unit of spongy bone?

-       made of trabezulcae Irregular lattice plates 3d networks providing strength and structural support; aligned differently to resist tearing from motion

What is structural unit of compact bone?

-       Organized Concentric lamellae in calcified in rings surrounding a haversian/central canal

-       Provides strength and resistance to stress and compression

What stimulates bone growth?

Mechanical Stress, Parathyroid Hormone, Sex Hormoes, Calcitonin, and Growth Hormone

Transverse Fracture

right across the bone (horizontal)

Spiral Fractures:

due to the rotating spiral motion

Communicated Fractures:

multiple fracture lines

Impacted Fracture

one bone impacts into another

Greenstick Fracture:

partial fracture (typical in kids)

Oblique Fracture:

on a angle fracture

Complete Fracture

broken all the way through

Incomplete Fracture

not broken all the way

Nondisplaced Fractures

: bone retains normal positions at the ends

Displaced Fracture

bones at end are out of normal alignment

Open(compound) Fracture

skin is penetrated

Closed Fracture

skin is not penetrated

Pulselessness

no pulse under the break

Paresthesia

numbness of the area

Poikilothermic

change in temperature above or below the break

Pain

t hurts

Pallor

unhealthy/ pain appearance

What are the 6 complications that may occur due to fractures?

-       Pulselessness: no pulse under the break

-       Paresthesia: numbness of the area

-       Paralysis: unable to feel or control movement

-       Poikilothermic: change in temperature above or below the break

-       Pain: it hurts

-       Pallor: unhealthy/ pain appearance

How does Growth Hormone regulate Bone Growth?

Increases bone length and promotes overall skeletal growth.; Secreted by the anterior pituitary gland; stimulates Insulin-like Growth Factor 1 (IGF-1) from the liver. IGF-1 promotes chondrocyte proliferation and bone elongation at the epiphyseal plate.

Thyroid hormone

. T₃ binds to osteoblast receptors, increasing RANKL expression and decreasing osteoprotegerin (OPG) — promoting balanced osteoclast formation for remodeling; Modulates bone metabolism and maintains growth proportionality.

Sex Hormones

regulate both osteoblast and osteoclast activity. Promote osteoblast function and bone deposition. At puberty, they also close the epiphyseal plate; aid in maintaining bone density

Parathyroid Horomone

Released when blood calcium is low. Binds to osteoblasts, increasing RANKL expression and promoting osteoclast formation and activity → releases calcium from bone.;Increases bone resorption and raises blood calcium levels.

Calcitonin

Produced by thyroid C cells. Inhibits osteoclast activity, decreasing bone resorption;

Weakens bones, increases osteoporosis risk, decreases bone formation.

What is Giganntism?

before puberty the secretion of adenomas before the fusion of the epiphyses causes excess growth hormone

What is Acromegaly?

after the fusion of the epiphyses, there is still exaggerated growth at the end of the extremities.

What are three types of dwarfisms?

-       Idiopathic GH Deficiency

-       Pituitary Tumors:

Laron-Type Dwarfism:

What is Idiopathic GH Deficiency?

 causes dwarfism due to the lack of GHRH being released from the thymus; increases the growth hormone to treat

What is  Pituitary Tumors:

the agenesis of the pituitary gland, causing lack of the growth hormone; treatment is to increase the growth hormone

What is Laron-Type Dwarfism?

  dwarfism caused by the missing receptors of the growth hormone; treatment: insulin-like growth receptors

What is a Potts Fracture

break in the lower fibula due to excess stress on the ankle (missing a step)

Colle’s Fracture:

a break in the distal radius in the wrist due to backward displacement of the hand

Smith’s Fracture

landing on the back of the hand (major damage)

Compression

fracture in the vertebrae ( falling off a chair or on the vertebrae)

Depression Fracture:

in the skull a depression, or opening

Time frame of a Fracture?

reduce the fracture to normal alignment and leave it immobile for 6-8 weeks

Steps of Healing a fracture?

1.)  Hematoma: base of where granulation grows

2.)  Inflammation

3.)  New blood Cells are created and invaded by Phagocytic Cells (remove the debris), Mesenchymal cells ( differentiate into chondrocytes producing collagen fibers and creating fibrocartilage), osteoblasts from periosteum and endosteum to create osteoid forming woven bone; the stress of bone remodeling them

What is Paget’s Disease

Abnormal remodeling of the bone, speeding up the process causing a decrease in density and fragility; pelvis femur, lumbar

  What is osteoprotegerin, what cells produce it, and what is its function

-       Osterogprotegerin : A decoy receptor Protein that inhibits bone resorption by binding to RANKL and prevents osteoclasts from forming, producing osteoblast and inhibiting osteoclasts

What is RANK and RANKL

is the protein that binds to the receptor found on cells, such as osteoclasts or osteocytes.; important in bone remodeling and reabsorption

What is RankL

ligand that binds to receptor Rank; secreted by osteoclast and osteocytes; promotes the activity of osteoclast in the cell

What is Rank

receptor that sits on the surface of the cell on osteoclast and precursor cells also increase the osteoclast activity

How do Bones Respone to stress?

With Bone Remodeling via Mechanical Stress and Horomonal changes

How often are bones replaces

 

-        bones are replaced 5-7% once a week

-       Spongy bone 3-4 years and compact every 10 years

How are structural joints connected?

Fibrous Tissue

Synarthrosis

immovable/nearly immovable

   Amphiarthrosis:

slight movable joint

Diarthrosis:

free movable joint in the synovial joins; provides major body moves and forms appendicular skeleton

Fibrous joints:

strong connections between bones connected by the fibrous tissue; synarthrosis& amphiarthrosis

Cartilage joints

connected by cartilage, either hyaline or fibrocartilage, providing strength; joints

Synovial joints:

a.     fluided space allowing the greatest range of motion; uses articulations and not connections.

  Uniaxial:

one direction (elbow, flexion and extension)

Biaxial

two directions (knuckle joint)

Multiaxial

  all directions (greatest range; ball and socket joint)

Categories of movement?

Pivot, HInge, Saddle,Plane/Glidng Joint, Condyloid Joint, Ball and Socket Joint

Pivot Joint:

rotation around the axis

1.    Hinge Joint

allows for flexion and extension

Saddle Joint

the bones are settle into one another (trapezium and metacarpal bone); abduction and abduction; and opposition

Plane/Gliding Joint

allows them to move past each other; non axial joint

Condyloid Joint;

in the wrist; flexion and extension, abduction and adduction

Ball and Socker

1.    allows for the greatest range of motion

Function oif Articular Cartilage

-       The layer of hyaline cartilage that covers the ends of bones in the synovial joints

o   To reduce friction, absorb shock and protect the underlying bone

What are types of fibrous joints?

Sutures, Syndesmosis Joint, and Gomphosis

What is a suture?

 is a example of fibrous joints because it’s an immovable joint

What is syndesmosis joint

 connects the radius to the ulna opr the tibia and the fibia via the interosseous membrane (amphiathrosis)

What is gomphosis

is peg in the socket type of joint suck as the teeth and is immovables

What is a cartilaginous joint

a tough but flexible hyaline or fibrocartilage

Synchondrosis

hyaline cartilage; used in the epiphyseal plate connecting the epiphysis to the diaphysis temporary joint

Symphysis

uses fibrocartilage and is slightly movable and is in the pubic symphysis