Essentials of Anatomy & Physiology, Chapter 6, Skeletal System

The following are major steps in the process of endochondral ossification:

1. Chondrocytes enlarge and calcify. 2. Blood vessels invade the perichondrium. 3. The perichondrium is converted into periosteum, and the inner layer produces bone. 4. Osteoblasts replace calcified cartilage with spongy bone. 5. Osteoclasts create a marrow cavity.

Pubic angle on the female pelvis

100 degrees

In adults, what percentage of protein and mineral components are removed each year and replaced through remodeling?

18%

Intramembranous ossification is usually complete by _______ years of age, whereas endochondral ossification is usually complete by ________ years of age.

2 years and 25 years

Trabeculae

An irregular network of thin plates of bone and fuse to form spongy bone and Red Bone marrow sits atop trabeculae

Condylar joints

Angular motion in two planes Occur where an oval surface nests with a depression on the other bone Example: is the joint between the radius and the proximal carpal bones

Osteopenia

Inadequate ossification that naturally occurs as part of the aging process

Diarthroses, a freely movable joint

Includes the synovial joints, the articular cartilages, and the joint capsule

Extension, an angular movement

Increases the angle between two bones example is straightening your arm out

Function of calcitriol

Increases the level of calcium in the body by increasing the uptake of calcium in the gut. and Stimulates the absorption of phosphate ions in the digestive tract

Periosteum (Histology)

Intermingles with the fibers of the tendons. and Has two layers: A fibrous outer layer and a cellular inner layer

Two types of embryonic bone formation

Intramembranous ossification and Endochondral ossification

Why doesn't the cartilage become bone in the forth step of endochondral ossification?

New cartilage is formed faster that the osteoblasts can form the new bone.

Are all bones remodeled?

Not every bone is affected. Regional differences occur. For example: Spongy bone of the femur may be replaced 2 to 3 times a year but compact bone remains largely untouched.

Lateral Flextion

Occurs when your vertebral column bends to the side

Cartilage

Often occurs in thin plates and receives nutrients and oxygen by diffusion

Bone is also known as

Osseous Tissue

What is the process where cartilage is replaced by bone?

Ossification

Two types of arthritis

Osteoarthritis and Rheumatoid Arthritis

Responsible for the production of bone matrix.

Osteoblasts

Which cells produce the bone matrix during endochondral ossification?

Osteoblasts

What types of cells are located in the marrow cavity?

Osteoblasts and Ostoclasts

Why does growth of bones finally end?

Osteoblasts outpace the new cartilage formation

Giant bone cells with 50 or more nuclei.

Osteoclasts

Responsible for the breakdown of bone.

Osteoclasts

What cells break down the spongy bone?

Osteoclasts

What occurs during bone remodeling?

Osteoclasts and osteoblasts are still working together even after the epiphyseal plates are closed. Osteons are broken down and rebuild.

What happens during osteoporosis?

Osteoclasts outpace osteoblast activity. The hips, wrists, and vertebrae are more likely to fracture than other bones because of falls and the weight leads to compression of vertebrae

Cells of the bone

Osteocytes

Osteoblasts that have become surrounded by matrix are now

Osteocytes

Central Canal or Haversian Canal

Osteocytes are arranged in concentric layers around the central canal. and Contains one or more blood vessels

Functional unit of compact bone

Osteon or Haversian system

Storage

Valuable mineral reserves of calcium salts. Maintains normal concentrations of calcium and phosphate ions in body fluids. Lipids are stored in yellow marrow for energy reserves.

Important for bone growth and remodeling

Vitamin A

A deficiency of this results in scurvy

Vitamin C

Produced by epidermal cells in response to UV light.

Vitamin D

The kidneys convert this substance into its active form.

Vitamin D

Rickets

Vitamin D deficiancy

How do we get calcitriol?

Vitamin D gets processed in the liver, then goes to the kidney where it gets converted into calcitriol

A deficiency of this results in rickets.

Vitamin D3

Plays a role in the calcification of bone.

Vitamin D3 and Calcitriol

In adults, osteocytes in lacunae maintain the matrix, removing and replacing the surrounding __________.

calcium salts

Tiny, cytoplasmic extensions of osteocytes that form a network throughout bone

canaliculi

The atlas is classified as a ________ vertebra.

cervical

Most common fractured bone

clavicle

The organic component of the matrix, which makes up around one-third of the mass of bone, is dominated by

collagen fibers

organic complex of of bone matrix, 1/3 of mass

collagen fibers

Closed or simple Fracture

completely internal

Articular cartilages

covers the end of long bones because you do not want the bones to contact each other

The bony compartment that supports the brain is called the ________.

cranium

Which of the following types of joints permit angular movement in a single plane (such as occurs between the interphalangeal joints)?

hinge joints

The joints between the phalanges are classified as

hinges

In synovial joint, blood vessels and nerves do not enter

the articular cartilage or the joint cavity

Calcification

the deposit of calcium salts It occurs during ossification

Blood cells are produced in

the marrow of many bones

Ossification

the process of replacing cartilage and other connective tissues with bone.

What is the purpose of osteoclasts breaking down bone matrix?

to regulate calcium phosphate concentrates in body fluids

Spongy bone is made up of a network of bony rods or plates called

trabeculae

Secondary ossification centers are located

in the epiphysis of the bone

What causes osteoporosis?

inactivity and low dietary calcium and is more common in woman and accelerates after menapause due to decline in circulating estrogens

Which maxillary region feature serves as an opening for a major sensory nerve from the face?

infra-orbital foramen

Connects the fibula and tibia

interosseus membrane

Arthritis

is Damage to the articular cartilage and Can be cause by infection, injury, or severe physical stress

Where does ossification occur during intramembranous ossification?

ossification center

What happens during osteopenia?

osteoblast activity slows and osteoclasts activity increases. and woman lose 8 percent of their skeletal mass every decade, men lose 3 percent and Mostly affects epiphyses, vertebrae and jaws and Results in fragile limbs, reduction in height, and loss of teeth.

Immature, active bone cells that produce new bone matrix are termed

osteoblasts

Giant multi-nucleated cells

osteoclasts

Cell surrounded by a hardened matrix and connected via canaliculi

osteocytes

Mature bone cells

osteocytes

The mature bone cells that recycle calcium salts and assist in repair are called __________.

osteocytes

The term for inadequate ossification is ___________.

osteopenia

Cells that undergo mitotic division and differentiate into immature bone cells

osteoprogenitor cells

Immature bone cells

osteoprogenitor cells and osteoblasts

Intramembranous Ossification begins when

osteoprogenitor cells undergo mistosis and differenciate into osteoblasts

Two hormones that work together to elevate calcium levels in the body are ________ and ________.

parathyroid hormone and calcitriol

Glides over anterior surface, between the lateral and medial condyles

patella

Appendicular skeleton

pectorial girdle upper limbs pelvic girdle and lower limbs

In endochondral ossification, the perichondrium that surrounds the hyaline cartilage becomes

periosteum

The connective tissue covering the outer surface of a bone is the

periosteum

The outer layer of bone, composed of dense, irregular, collagenous connective tissue that contains blood vessels and nerves is called

periosteum

Open or compound fracture

projects through skin

In anatomical position, when the palm is moved to face posteriorly, the movement of the wrist and hand is called ________.

pronation

When one crosses his/her arms, which movement is performed by the clavicles?

protraction

The function of synovial fluid is to

provide lubrication

The lumbar curve develops

After birth

Ball-and-socket joints

All combinations of movement - angular, rotational, and circumduction they occur where the end of one bone is a round head that nests within the cup-shaped depression in the other bone they Allow for a wide range of motion Examples are: the hip and shoulder joints.

What is the function of the epiphyseal plates?

Allow for growth to occur lengthwise

Spongy Bone

Also called cancellous bone .... Network of rods or struts. separated by space .... Fills the epiphysis and lines the marrow cavity

Slightly movable joints

Amphiarthroses

Compact bone

Densely packed Forms Diaphysis

Downward movement of the body

Depression

Longest bone in the body

Femur

Skulls of infants and children

Fetal development of skull bones occurs around the developing brain. At birth, the cranial bones are connected with connective tissue called fontanels.

Three types of joints

Fibrous, cartilaginous, and synovial

What is the function of the hyaline cartilage located between the epiphyses and diaphysis?

Responsible for growth in the lengthwise direction

To pull a projected part of the body backward

Retraction

Diaphysis

Shaft of bone Filled with bone marrow (long bone)

Where does bone formation first occur during endochondral ossification?

Shaft surface

Axial skeleton

Skill, thoracic cage, including ribs and sternum and the vertebral column.

Canaliculi

Small channels that run through the matrix. and Connect to the lacunae and blood vessels

Lacunae

Small pockets where bone cells are located

What type of bone is located at the end of long bones?

Spongy Bone

Bone where no osteons are present

Spongy bone

Composed of trabeculae.

Spongy bone

Found where bones are not heavily stressed or where stress arrives from many directions.

Spongy bone

Microscopic spaces are present between the hardened matrix of bone.

Spongy bone

What do osteoblasts form at the primary ossification center?

Spongy bone

When does osteopenia occur?

Starting between the ages of 30 and 40

Five steps of Endochondral Ossification

Step 1 - Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calcifies. Step 2 - Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone Step 3 - Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center. Step 4 - The bone of the shaft thickens, and the cartilage near each epiphyses is replaced by shafts of bone. Step 5 - Blood vessels invade the epiphyses and osteoblasts form a secondary centers of ossification.

Supination

Turning the palm forward

Inversion

Twisting the sole of the foot inward. This is a common way to sprain your ankle

Eversion

Twists the foot outward

Bones encased within the temporal bone that are involved in sound detection are called

auditory ossicles

Embryonic development of bone

begins 6 weeks after fertilization as a cartilaginous formations ..... they are like miniature models of future bones

Which of the following primary functions of the skeletal system applies to the role of bone marrow?

blood cell production

Bones can heal after severe damage, as long as the __________ remains and the cellular components of the periosteum and endosteum survive.

blood supply

Compound fracture

bone projecting through skin

A compound fracture results in

bone projecting through the skin.

Saddle joints

bones fit together like rider in a saddle Angular in two planes, and circumduction They have two bones that each have a concave face on one axis and convex on the other Allowing for circumduction, but not rotation Example is: twiddling your thumbs

a thin fibrous cartilage between the surfaces of some joints, like the knee.

meniscus

Bone matrix hardens after the addition of these

mineral salts

Abduction

moves a limb away from the body example is swinging your arms to the side or separating the fingers

Which cell populations are particularly sensitive to changes in calcium ion concentration?

neurons and muscle cells

Pott's Fracture

occurs at the ankle and affects bones of the leg

The point of the elbow is called the

olecranon

The special movement of the thumb that allows it to grasp an object and hold onto it is called

opposition

Immovable joints

synarthrosis

The term for a functionally immovable joint is

synarthrosis

When does the bony skeleton begin to form?

6 weeks after fertilization

When does the bony skeleton start to form?

6 weeks after fertilization

Osteoprogenitor

A stem cell that can undergo mitotic division and They differentiates into an osteoblast. and are located in the inner cellular layer of the periosteum, the endosteum and lining osteonic canals.

Depression

A structure moves in an inferior direction example is opening your mouth

Elevation

A structure that moves in a superior direction example is closing your mouth

Calcium Reserve

A typical human body contains 2.2 to 4.4 pounds of calcium. Nintey-nine percent is stored in skeleton and Balance calcium in the body and essential for many physiological mechanisms.

Meniscus

Additional padding in synovial joints and acts like shock absorbers and is found in the knee

Movement away from the midline of the body

Abduction

Movement to the midline of the body

Adduction

What covers the ends of the epiphyses?

Articular Cartilage

Bone that allows for "nodding yes"

Atlas

Allows for rotation "shaking your head no"

Axis

Intramembranous Ossification

Bone develops within sheets of connective tissue and Results in the formation of flat bones of the skull including frontal, parietal, occipital, temporal bones also includes the clavicles and the mandible

The inorganic, structural material of bone

Bone matrix

Colles fracture

Break in the distal portion of the radius

What is the process called where deposits of Calcium are laid down?

Calcification

What causes the chondrocytes to die during endochondral ossification?

Calcified matrix slows the diffusion of nutrients

Plays a role in the absorption of calcium and phosphate ions from the intestinal tract.

Calcitriol

Hormones that raise calcium levels in body fluids

Calcitriol and parathyroid

What is calcitriol?

Calcitriol is the hormonally active metabolite of Vitamin D

Bones are largely composed of

Calcium Phosphate - A salt deposited into the matrix and accounts for 2/3 of the bone weight. Remaining 1/3 is collagen fibers.

The most important mineral required for bone growth?

Calcium salts

Synarthrosis or immovable joints

Can be fibrous or cartilaginous examples are Sutures of the skull interlocked with dense connective tissue and Gomphoses, a ligament binding each tooth in the socket and Synchondrosis, a rigid cartilaginous connection. For example between the first pair of ribs and the sternum

Transports nutrients and respiratory gasses from nearby blood vessels to neighboring osteocytes.

Canaliculi

What is the skeleton made of initially

Cartilage

What is the skeleton made of initially?

Cartilage

Haversian canal

Central canal that contains one or more blood cells

Which of the following curves helps a baby hold it's head up?

Cervical Curve

Appositional growth of cartilage

Chondroblasts in the perichondruim lay down new matrix

Endochondral ossification starts with the

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calcifies.

Forms the external layer of all bones; it may be a thin or thick layer.

Compact bone

Important for protection and support of the body and functions to withstand forces applied at either end of a bone

Compact bone

Osteons are the function units of this type of bone.

Compact bone

What type of bone comprises the shaft of a long bone?

Compact bone

Bone

Contains an abundant intercellular matrix, and has widely dispersed cells

Characteristics of compact done

Covers all bone surfaces except for articular surfaces. And Can tolerate a lot of stress applied to either end of a long bone. (Limb bones) And Cannot tolerate moderate stress applied to the side of the shaft.

Secondary curves of the spine

Develop several months after birth and project anteriorly and include the cervical curve, which keeps the head up and the lumbar curve which develops with the ability to stand

What is the shaft of long bones called?

Diaphysis

Freely movable joints

Diarthroses

Why are astronauts concerned about their bones?

Due to the lack of gravity there isn't any stress put on their bones. Degeneration occurs even after a brief period of inactivity. After a few weeks an unstressed leg can lose up to a third of it's bone mass. This is also a concern when people have to use crutches after an injury.

Dorsiflexion

Elevates the sole at the ankle. Example is putting the heel down and toes up

Upward movement of the body

Elevation

What is the lining of the marrow cavity called?

Endosteum, the cellular lining of the medullary cavity.

Epiphysis

Ends of long bone House red bone marrow Covered with articular cartilage

What cells manufacture Vitamin D after UV exposure?

Epidermal cells

What is located between the epiphyses and diaphysis?

Epiphyseal Plate or Growth Plate

What remains of the epiphyseal cartilage in the adult?

Epiphyseal line

What are the ends of long bones called?

Epiphyses

Physiological mechanisms of calcium in the body

Essential for nerves and muscles and an increase in calcium by 30 percent or more causes neurons and muscles to become unresponsive and a decrease in calcium by 35% or more causes neurons and muscles to become excitable and convulsions may occur

Movement of the soles of the feet outward

Eversion

To increase the angle between articulating bones

Extension

Four steps of intramembranous ossification

First, osteoprogenitor cells undergo mistosis and differenciate into osteoblasts ................... Second, Osteoblasts secrete the matrix of bone and become osteocytes when they are fully surrounded by matrix. Then, mineral salts are added. .................... Third, as bone matrix forms it develops trabeculae that fuse together and form spongy bone. .................... Fourth, The periostium forms on the external surface of the bone and Remodeling of some of the spongy bone produces osteons of compact bone. Some of the spongy one remains in the center.

What bones are formed from intramembranous ossification?

Flat bones of the skull, mandible, and clavicles

Movement of hips and shoulders

Flex by moving forward and extend by moving backward

Fontanelles

Flexible soft spots that allow for easier delivery of the head. They disappear by age 4 and skull growth is finished.

Decrease the angle between articulating bones

Flexion

Fat pads

Found in synovial joints and acts as a cushion

Functions of the Axial skeleton

Framework for support and protection of the brain, spinal cord, and organs of the ventral body cavity. and Provides surface area for attachment of muscles that move the head neck and trunk muscles that perform respiration and muscles that stabilize elements of the appendicular skeleton.

How long does bone formation and growth last?

From 6 weeks after fertilization - the embryo is about .5" long at this time. It lasts until the end of adolescence. Some portions of bone do not stop until the age of 25

Types of synovial joint movement

Gliding, angular movements, rotation, and special movements

Hormones required for normal bone growth?

Growth hormone Sex hormone Thyroid hormone and the Calcium balancing hormones

Synovial joint, a freely movable joint

Has a wide range of motion and is usually found at the ends of long bones

A vertical canal that transports blood vessels and nerves into bone

Haversian canal

Blood Cell Production

Hematopoiesis Red blood cells, White blood cells, and platelets are produced in red bone marrow.

skull

Houses brain and sense organs for sight, smell, taste, and balance. Has 22 bones, 8 are cranial, and 14 are facial Skull bones are joined by tight connections called sutures.

What type of cartilage composes the epiphyseal plate?

Hyaline Cartilage

The only bone that does not articulate with another bone.

Hyoid

Define and describe the process of intramembranous ossification.

Intramembranous ossification is the process by which bone develops within sheets or membranes of connective tissue. This process begins when osteoblasts differentiate within embryonic or fetal fibrous connective tissue. This type of ossification normally occurs in the deeper layers of the dermis. The osteoblasts differentiate from connective tissue stem cells after the organic components of the matrix --- secreted by the stem cells-- and become calcified.

Movement of the soles of the feet inward

Inversion

Vitamin D3

Involved in calcium metabolism and Needed to prevent diseases such as Rickets. Rickets is a Vitamin D3 deficiency which softens the bones. Children with rickets have bending of the bones.

Rotational joint movements

Involves turning around the longitudinal axis of the body or limb. Example of this is turning your head from side to side.

Osteoarthritis

Is a degenerative arthritis that results from wear and tear or can be genetic and Affects older people usually 60 years old and up

Syndesmosis, a slightly movable joint

Is a fibrous joint that is connected by a ligament and found between the tibia and fibula

Rheumatoid Arthritis

Is an inflammatory condition Some cases are due to autoimmune attack on the joints

Calcitonin

Is from the thyroid gland lowers calcium levels in body by putting it back into bone.

Symphysis, a slightly movable joint

It is cartilaginous, connected by a fibrocartilage pad and found between the right and left halves of the pelvis also found between adjacent vertebrae

Why is regular exercise important for the bones?

It is the key to maintaining normal bone structure and strength by promoting remodeling. Making bones thicker and stronger.

Ligaments

Join bone to bone

Joint capsule

Joint is surrounded with a fibrous joint capsule The inner surfaces are lined with the synovial membrane and filled with synovial fluid to reduce friction

Open areas that surround osteocytes

Lacunae

Spongy bone

Lamella forms rods or plates called trabeculae. And. Has no osteons. Is Found in the epiphysis of long bones where the stress is handled by joints. Is much lighter than compact bone reducing the amount of work for the muscle.

Concentric layers of calcified matrix

Lamellae

Osteoclasts

Large, multinucleated cells that secrete acid and enzymes to break down the matrix

Endosteum

Lines the marrow cavity in spongy bone

Osteocytes (bone cells) are located where in bone?

Located in the lacunae. and Found between the sheets of matrix called lamellae

Osteoporosis

Loss of bone mass that impairs normal function and can lead to more fractures.

Which of the following curves as the child begins to stand or walk?

Lumbar Curve

Osteon

Made of concentric circles of lamella. And Surrounds a central canal the contains blood vessels.

Why are bones remodeled?

Maintains the integrity of the skeletal system. Bones not regularly stressed become thin and brittle.

Movement

Many bones function as levers that change the magnitude and direction of the forces generated by skeletal muscles.

Protection

Many soft tissues and organs are surrounded by the skeleton. Examples are: The ribs protect the heart and lungs. The skull encloses the brain. The vertebrae shields the spinal cord. The pelvis cradles digestive and reproductive organs.

What is the open area surrounded by diaphysis called?

Marrow Cavity

What do osteoclasts create during endochondral ossification?

Marrow cavity

Bone tissue

Matrix consists of extracellular protein fibers and a ground substance

Osteocyte

Mature bone cells, The main bone cells in bone tissue

Bone matrix hardens after the addition of these.

Mineral Salts

Endochondral Ossification

Most bones are formed this way ............. The cartilage develops first .................. They are formed through ossification of existing hyaline cartilage ..................

Protraction

Move part of the body anteriorly such as grasping your upper lip with your lower teeth. Retraction is the opposite of this.

Adduction

Moves limbs toward the body example is bringing your fingers back together

Circumduction

Moves the limbs in a loop Think sparklers on the forth of July

Opposition

Moving the thumb toward the palm or fingertips to grasp

Lamellae

Narrow sheets of calcified matrix Lacunae are found in Lamellae

How do osteoporosis and osteopenia differ?

Osteoporosis is a condition that produces a reduction in bone mass great enough to compromise normal function. The difference between the "normal" osteopenia or inadequate ossification of aging and the clinical condition of osteoporosis is a matter of degree

Stem cells that have the ability to become osteoblasts or chondroblasts

Osteoprogenitor Cells

Periosteum

Outer covering of bone. and Supports and protects

What roles do the hormones, parathyroid hormone (PTH), calcitonin, and calcitriol, play in maintaining calcium homeostasis?

PTH - from the parathyroid glands and calcitriol -- from the kidneys work together to elevate calcium levels in body fluids. Their actions are opposed by calcitonin, a thyroid gland hormone that depresses calcium levels in body fluids.

Parathyroid hormone

PTH from the parathyroid gland and calcitriol from kidneys work together to elevate calcium levels in body fluids.

PTH is secreted from the ________, whereas calcitonin is secreted from the _________.

PTH is from the parathyroid gland and Calcitonin is from the thyroid gland

What is the function of articular cartilage on the end of long bones?

Pads the surfaces between two bones in the joint.

Hormones that raise calcium in blood

Parathyroid hormone and calcitriol

What covers the outer surface of the diaphysis?

Periosteum, a tough connective tissue sheet that functions to support and protect the bone.

Hinge joints

Permit angular movement in one plane are Like opening and closing a door Examples: joints at the elbow, knee and ankle

Pivot joints

Permit rotation only, in a single plane an Example: is the joint between the atlas and axis Like turning the head or supinating and pronating the palm

Osteoblasts

Produce new bone through ossification and promote deposition of calcium salts into the matrix

What is the function of red marrow?

Production of red and white blood cells

Primary curves of the spine

Project posterior and include the thoracic and sacral curves.

Movement of the mandible or shoulder girdle forward

Protraction

Perforating canal

Provides passageways for blood vessels in the central canal to be linked to other vessels

Vitamin A and Vitamin C

Provides support for osteoblasts and Vitamin C deficiency can cause scurvy. Scurvy is a reduction of osteoblasts that leads to brittle bones.

Support

Provides support to the entire body. Individual bones or groups of bones provide framework for the attachment of soft tissues and organs.

Synovial fluid

Reduces friction in a synovial joint

Four steps of fracture repair

Step 1) Fractures result in broken blood vessels that cause a blood clot called fracture hematoma. The blood clot closes off blood supply and Kills osteocytes and Results in dead bone on either side of the fracture

Four steps of fracture repair

Step 2) Cells of periosteum develop into an external callus and cells of the endosteum collect at the fracture and form an internal callus

Four steps of fracture repair

Step 3) Osteoblasts replace new cartilage with spongy bone

Four steps of fracture repair

Step 4) Spongy bone is replace by compact bone. It will leave a slightly thicker spot at the fracture site.

Growth hormone (GH) is released by the cerebellum in small amounts while sleeping. What does it do?

Stimulates bone and skeletal muscle growth and Binds to chondrocytes and stimulates mitosis

Functions of the Skeletal Sytem

Support Storage Hematopoiesis - Blood cell production Protection Movement

Amphiarthroses or slightly movable joints

Symphysis and Syndesmosis

Appositional growth

The enlargement of bones in diameter, occurs at they grow longer and Periosteum cells develop into osteoblasts and produce more matrix on the outer surface of the bone and Osteoclasts erode the inner surface enlarging the marrow cavity

Bursa

The packet of connective tissue containing synovial fluid. It also acts to reduce friction and absorb shock

Pronation

The palm is facing the front and is then rotated to the back

What causes growth spurts occur during puberty?

The release of sex hormones such as testosterone and estrogen stimulates an increase of osteoblasts activity

Ostolysis

The releasing of material from broken down bone matrix or reabsorbtion

Bone remodeling

The skeleton is recycled and replaced. The turnover rate for bone in young adults is almost one-fifth of the skeleton each year.

Discuss the importance of vitamin D3 in normal calcium metabolism.

Vitamin D3 can be obtained from dietary supplements or manufactured by epidermal cells exposed to UV radiation. After it has been processed in the liver, the kidneys convert a derivative of this vitamin into calcitriol, a hormone that stimulates the absorption of calcium and phosphate ions in the digestive tract.

Synovial movement of gliding

When two opposing surfaces slide past each other and movement in any direction, but it is slight examples are carpals and tarsal bones

Depressions, grooves, and openings

Where blood vessels and nerves pass through the bone.

projections

Where tendons and ligaments attach and where bones articulate. Meaning the joining of two bones.

An immovable joint is known as?

a synarthrosis

Slightly movable joints

amphiarthrosis

The presence of ________ strongly indicates that the long bone is still growing.

an epiphyseal plate

Flexion, an angular movement

decreases the angle between two bones example is bending your arm or bending at the waist

The hormone calcitonin functions to

depress calcium levels in body fluids

Freely movable joints

diarthrosis

The skeletal system is largely under the physiological control of the ____________.

endocrine system

The surface of the medullary cavity of long bones is lined with a connective tissue membrane called

endosteum

The presence of an epiphyseal line indicates

epiphyseal growth has ended

Hyperextension

extension beyond anatomical position such as looking up at the sky also think whiplash

A small, flattened articular surface is a

facet

Movement in the anterior-posterior plane that decreases the angle between articulating bones is which movement?

flexion

The general term for a depression in a bone is

fossa

Which structural feature of the scapula articulates with the humerus?

glenoid cavity or glenoid fossa

Plantar Flexion

is to point the toes common position for ballet dancers

A point where two joints meet

joint

The bones of the limbs are classified as

long bones

Hormone calcitonin functions to

lower calcium levels in body fluids

Considering the bony structure of the palate, a cleft palate is a malformation of which bone?

maxillary

Fibrous cartilage discs that act as shock absorbers in joints are called ________.

menisci

Reposition

returns the thumb form opposition

Which bone acts like a bridge that unites the cranial and facial bones?

sphenoid bone

The vertebral arches contribute structurally to surround and protect the

spinal cord

Skull bones are joined by tight connections called

sutures

Amphiarthrotic joints that are connected by a fibrocartilaginous pad are called __________.

symphyses

The typical vertebra's ________, projecting laterally or dorsolaterally from the pedicles, serves as a site for muscle attachment.

transverse process

Ribs that are connected to the sternum by separate cartilaginous extensions are called ________ ribs.

true

Rickets is a condition marked by a softening and bending of bones that occurs in growing children, as a result of ________ deficiency.

vitamin D3

The most inferior portion of the sternum is called the

xiphoid process