The Skeletal System Flashcards
What are the functions of the skeletal system
-To support the body
-To facilitate movement by being attachment points for muscles
-To act as levers for joints which serve as fulcrums
-To protect internal organs from injury
-To serve as a reservoir for a number of important minerals
-To act as a site for fat storage
What is hematopoiesis?
The production of blood cells in the red marrow
How many groups of classes are the 206 bones of the body divided into?
5 groups of classes
What shape are the long bones class of bones?
-Cylindrical
-Longer than they are wide
Where are long bones found in the human body.
-The arms(humerus, ulna,radius)
-The legs(Femur, Tibia, Fibula)
-The fingers(Phalanges, Metacarpals)
-The toes(Phalanges, Metatarsals)
What is the function of long bones?
They act as levers; they move when muscles contract
What is the shape of short bones?
-Cube like in shape
-Equal in length, width, and thickness
Where are short bones found in the human body?
-Tarsals of ankles
-Carpals of wrists
What is the function of short bones?
-They provide stability and support
-They have limited motion
What is the shape of flat bones?
-Thin
-Typically curved
Where are flat bones found in the human body?
-Cranial(Skull)
-Scapulae(Shoulder blades)
-Sternum(breastbone)
-Ribs
What is the function of the flat bones?
-They served as points of attachment for muscles
-They protect internal organs
What is the shape of irregular bones?
They do not have an easily characterized shape
Where are irregular bones found in the human body?
-The vertebrae
-Many facial bones
What is the function of irregular bones?
The vertebrae support the spinal cord and protect it from compressive forces
What is the shape of sesamoid bones?
-Small
-Round
-Sesame seed shaped
Where are sesamoid bones found in the human body?
-They are found in the tendons
What is unique about sesamoid bones in every human?
-they differ in number and placement from person to person
What is the one sesamoid bone found in everyone?
The patella
What is the function of sesamoid bones?
Protect the tendons from wear and tear
What 2 parts make up long bones?
-Epiphysis
-Diaphysis
What is the hollow region of the diaphysis called?
The medullary cavity
What is the medullary cavity filled with?
Yellow Marrow
What are the walls of the diaphysis composed of?
Compact bone
What is the wide section at the end of each bone called?
The epiphysis
What is the epiphysis filled with?
Spongy red bone marrow
Where does each epiphysis meet the diaphysis?
It meets the diaphysis at the metaphysis
What is the metaphysis?
It is a narrow area that contains the epiphyseal plate
What is the epiphyseal plate?
It is a layer of hyaline cartilage in a growing bone
What happens to the epiphyseal plate when the bone stops growing in adulthood?
The epiphyseal hardens and becomes osseus tissue and the epiphyseal plate becomes the epiphyseal line
What is the lining of the medullary cavity called?
The endosteum
What happens in the endosteum?
It is the area where bone growth , repair and remodeling occur
What is the outer surface of the bone covered with?
A fibrous membrane called the periosteum
What does the periosteum contain?
It contains blood vessels, nerves, and lymphatic vessels that nourish the compact bone
Where do tendons and ligaments attach to bones?
The periosteum
What surface does the periosteum cover?
It covers the entire bone outer surface area except where the epiphyses meet other bones to form joints
What are epiphysis covered by?
They are covered by articular cartilage
What is the function of the articular cartilage?
It acts as a shock absorber
What is the anatomy of a flat bone?
-Top layer of compact bone
-Middle layer of diploe (spongy bone)
-Bottom layer of compact bone
What is the purpose of flat bone anatomy?
If the outer layer (top layer of compact bone) of bone fractures, the brain is still protected by the inner(bottom layer of compact bone) layer.
What are bone markings?
The different surface features of bones that vary depending on function and location
What are the three different classes of bone markings?
-Articulations
-Projections
-Holes
What is an articulation class bone marking?
Articulation is where two bone surfaces come together (articulus = joint)
What is the physical description of articulate class bone markings?
Surfaces tend to conform to one another such as one being rounded and the other being cupped
What is a projection type bone marking?
A projection is an area of a bone that projects above the surface of the bone
What are the physical characteristics of projection bones?
These bones are attachments points for tendons and ligaments. Size and shape are indications of the forces exerted through the attachment to the bone.
What is a hole type bone marking?
An opening or groove in a bone that allows blood vessels and nerves to enter the bone.
What are the physical characteristics of hole type bone markings?
Size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.
Which bones in the human are articulate type bone markings?
-Head(prominent rounded surface like head of femur)
-Facet(flat surface where synovial joints connect vertebrae to the spine)
-Condyles(Rounded knobs like femur condyles or occipital condyles)
-Knee Joint
Which types of bones have projection markings?
-protuberance(chin)
-process(transverse process of vertebrae)
-spine(ischial spine)
-tubercle(tubercle of humerus)
-tuberosity(deltoid tuberosity)
-line(temporal lines of the parietal bone)
-crest(iliac crest)
What bones have hole bone markings?
-Fossa(mandibular fossa)
-Fovea(fovea capitis on the head of the femur)
-Sulcus(sigmoid sulcus of the temporal bones)
-Canal(auditory canal)
-Fissure(auricular fissure)
-Foramen(foramen magnum in the occipital bone)
-Meatus(external auditory meatus)
-Sinus(nasal sinus)
What two materials is the skeletal system a reservoir for?
It is a reservoir for calcium and phosphorus
Why are calcium and phosphorus stored in the bones?
The bones play an important role in calcium homeostasis, they maintain the balance of these substances in the body. They bones provide rapid turnover of these substances when needed
What type of blood cells does the red marrow produce?
It produces erythrocytes (red blood cells)
It also produces leukocytes(white blood cells)
What type of cells does yellow marrow produce?
It produces adipocytes(fat cells)
What are osteoblasts?
Osteoblasts are specialized cells responsible for bone formation
What are osteogenic cells?
They are the stem cell precursor to osteoblasts and osteocytes
What are osteoclasts?
Osteoclasts are large cells that breaks down bone tissue
What does the fibrous outer layer of the periosteum composed of?
It is composed of collagen
What is the outer most layer of compact bone?
Circumferential Lamellae
In what direction do circumferential lamellae run in comparison to the bones surface? Why?
They run parallel to the bone’s surface.
They provide additional strength and resistance against twisting forces.
What is the periosteal artery?
It is the blood vessel supplying the periosteum and outer bone layers
What is the periosteal vein?
The periosteal vein drains blood from the outer layers of the bone and the periosteum
What are interstitial lamellae?
They are irregularly shaped bony plates that fill in the spaces between osteons in compact bone.
What are perforating canals/Volkmann’s canals?
They are microscopic channels in the bones that allow blood vessels to enter the bone from the periosteum.
What are perforating canals/Volkmann’s canals?
They are microscopic channels in the bones that allow blood vessels to enter the bone from the periosteum.
What is the central canal/haversian canal?
It is the central channel of an osteon carrying blood vessels and nerves.
What are concentric lamellae?
They are concentric layers of bone surrounding the central canal in an osteon
What is an osteon/haversian system?
It is the primary structural unit of compact bone. It consists of concentric lamellae surrounding a central canal
What are trabeculae?
They are the thin columns and plates of bone that create a spongy structure in cancellous bone.
How many bones make up the facial portion of the skull?
14
What do we call the group of bones that protect organs in the chest?
Thoracic cage
What is another name for the breastbone?
The sternum
What is another name for the breastbone?
The sternum
What is the appendicular skeleton?
The appendicular skeleton refers to the limbs, pelvis and shoulder bones
What is the bone framework that supports the upper limbs?
The pectoral girdle
What does the pectoral girdle consist of?
It consists of the clavicle and the scapula.
What is the function of the pelvic girdle?
The pelvic girdle connects the upper limbs to the axial skeleton and it enables arm movements and provides an attachment point for muscles
What is the name of the long bone between the scapula and sternum?
The clavicle
What is the name for the flat, triangular bone on the back that connects the clavicle and humerus?
It is called the scapula
How far does the upper limb stretch?
It stretches from the shoulder to the hands
How many bones make up the carpals in the wrist?
8 bones
How many bones make up the tarsals in the ankles.
7 bones
How are the bones of the carpals arranged in the wrist?
They are arranged in 2 rows
What is the function of the tarsals in the ankle?
They allow for foot movements and support body weight
How many bones make up the metatarsal bones in the feet?
5 long bones
What is the function of the metatarsal bones on the feet?
-They form the foot’s arch and enable movements like jumping, running. -They provide structural support and flexibility
What is the bone structure that connects the spine to the legs?
The pelvic girdle
What bones make up the pelvic girdle?
-The hip bones
-Sacrum
-Coccyx
What is the function of the pelvic girdle?
-Provides support for internal organs
-Facilitates movement like walking and sitting
What is the brain case?
The brain case is the bony structure that protects the brain
What is the coronal suture?
It is a joint connecting the frontal and parietal bones
What is the shape of the coronal suture?
It is a fibrous, joint that runs horizontally across the skull separating the frontal and parietal regions
What is the smooth area between eyebrows and above the nasal bridge called?
It is called the glabella
What is the bone that forms the forehead and upper eye sockets called ?
It is called the frontal bone
What is the purpose of the frontal bone of the skull?
It protects the brain’s frontal lobes
What is the large bone that forms the roof and sides of the skull?
The parietal bone
What is the opening above the eye for blood vessels and nerves?
The supraorbital foramen
What is the supraorbital margin?
It is a prominent ridge located above the eye socket.
What is the function of the supraorbital margin?
-It offers structural support for the eye -It is an attachment point for several facial muscles
What is the eye socket that holds the eye called?
It is called the orbit
What is the purpose of the eye orbit?
-It provides protection
-it provides optimal position for vision
What is the optical canal?
It is the pathway for the optic nerve from the eye to the brain
What two parts make up the pelvis in the human skeleton?
-The pelvic spine
-The pelvic girdle
What is another name for the pelvic girdle?
Os Coxae
What three bones make up the pelvic girdle?
-Ilium
-Ischium
-Pubis
What two bones make up the pelvic spine?
-The sacrum
-The coccyx
What is endochondral ossification?
The conversion of cartilage models to bone
What do most bones originate as during development?
They originate as hyaline cartilage
What is the purpose of cartilage during the development process of bone?
The cartilage is a miniature model of the bone that will occupy that particular position in the adult skeleton.
What is an articulation or joint?
A place of junction between two or more bones of the skeleton.
What are the three types of articulations(joints)?
-immovable(synarthrosis)
-slightly movable(amphiarthrosis)
-freely movable(diathrosis)
What are the most popular types of joints or articulations in the human body?
Diarthrosis joints
List the numeric distribution of bones in the skull and the total number of each.
-The skull has 28 bones
-8 are cranial bones
-14 are Facial bones
-6 are Auditory ossicles
How many bones does the axial skeleton contain?
80 bones
How many bones does the thoracic cage contain?
25 bones
How many bones does the appendicular skeleton contain? What is their distribution?
-126 bones
-60 upper extremity
-60 lower extremity
-2 pelvic girdle
-4 pectoral girdle
What is the hyoid bone?
It is a U-shaped bone in the neck that supports the tongue.
What are the four curvatures in the human body with regards to bones?
-Cervical curve
-Thoracic curve
-Lumbar curve
-Sacral curve
How many vertebrae make up the spinal column of the human adult?
The human body has 26 vertebrae
What else is a part of the spinal/vertebral column?
Intervertebral disks
What is the atlas?
The atlas is the first cervical vertebrae
What bones does the atlas articulate with?
It articulates with the occipital bone and the axis.
What is the axis?
The second cervical vertebrae
What does the axis articulated with?
The atlas
What does the articulation of the atlas and the axis cause?
This articulation allows the head to be turned(rotated), extended and flexed.
What is the coccyx?
The last bone at the base of the vertebral column
What is the sternum?
The sternum is a bone that forms the anterior portion of the thoracic cage
What bones make up the sternum?
-Manubrium
-Body(gladiolus)
-Xiphoid process
What is the function of the sternum?
It supports the clavicles
What does the sternum articulate with?
It directly articulates with the first 7 pairs of ribs
What are the True Ribs?
The true ribs are the seven pairs of ribs, which attach to the sternum directly by their individual costal cartilage.
What are the False ribs?
Ribs in pairs 8 through 10, which attach to the sternum indirectly.
What are the floating ribs?
The floating ribs are ribs in pairs 11 and 12 which do not attach to the sternum.
What is the pectoral girdle?
The skeletal structure consisting of the two clavicles (collarbones) and the two scapulae
What is the olecranon process?
The olecranon process is a projection on the ulna that forms the bony point of the elbow.
What is the styloid process?
A projection on the temporal bone
What are fibrous joints?
Fibrous joints means that articulating bones are fastened together by a thin layer of dense connective tissue.
What are the possible movements between bones that are attached together with fibrous joints?
None
What are examples of bones joined together with fibrous joints?
-The suture between the bones of the skull
-The joint between the distal ends of the tibia and fibula
What is a cartilaginous joint?
A cartilaginous joint involves bones connecting by hyaline cartilage or fibrocartilage
What type of movement occurs between cartilaginous joints?
Limited movement; like when back is bent or twisted
What are examples of bones joined by cartilaginous joints?
They are joints between the bodies of vertebrae, symphysis pubis.
What is the symphysis pubis?
It is a joint that joins the left and right bones of the pelvis made of fibrocartilaginous disk.
What is a synovial joint?
-A synovial joint involves bones surrounded by a joint capsule of ligaments and synovial membranes.
-The ends of articulating bones are covered by hyaline cartilage and separated by synovial fluid.
What type of movement do synovial joints allow?
Free movement
What is a ball-and-socket synovial joint?
It is a ball shaped head of one bone that articulates with a cup shaped cavity of another bone.
What type of movement does a ball-and-socket shaped synovial joint allow?
-Movements in all planes and rotations
What is an example of a ball-and-socket shaped synovial joint?
Shoulder and hip joints
What is a condyloid synovial joint?
It is an oval shaped condyle of one bone that articulates with elliptical cavity of another.
What type of movement does a condyloid synovial joint allow?
A variety of movements in different planes but no rotation
What are examples of condyloid joints?
Joints between the metacarpals and phalanges
What are Gliding synovial joints?
Gliding synovial joints occur when articulating surfaces are nearly flat or slightly curved.
What type of movements do Gliding synovial joints allow?
Sliding or Twisting
What are examples of Gliding synovial joints in the body?
-Joints between various bones of wrist and ankle,
-Sacroiliac joints
-Joints between ribs 2-7 and sternum
What are hinge synovial joints?
Convex surface of one bone articulates with concave surface of another
What type of movements do hinge synovial allow?
Flexing and extension
What are examples of hinge synovial joints?
-Elbow
-joints of phalanges
What are pivot synovial joints?
The Cylindrical surface of one bone articulates with the ring of bone and ligament.
What type of movements do pivot synovial joints allow?
Rotation around a central axis
What are examples of pivot synovial joints in the body?
The joints between the proximal ends of the radius and ulna
What are saddle synovial joints?
Articulating surfaces that have both concave and convex regions. The surface of one bone fits the complementary surface of another.
What type of movements do saddle synovial joints allow?
A variety of movements
What are examples of saddle synovial joints in the body?
Joints between the carpal and the metacarpal of the thumb
What is the acetabulum?
It is the deep depression on the lateral surface of the hipbone, on which the ball shaped head of the femur articulates
What is the obturator foramen?
The obturator foramen is a large opening on each side of the lower part of the hip bone
What is the malleolus?
It is a rounded bony process on each side of the ankle.
What brain region does the sphenoid bone protect?
The pituitary gland
What bone separates the nasal cavity from the brain?
The ethmoid bone
What bone houses the olfactory foramina for smell?
The ethmoid
What bone houses the olfactory foramina for smell?
The ethmoid
What bone is the bridge of the nose?
The nasal bone
What bones are responsible for forming part of the hard palate at the back of the mouth?
The palatine bones
What is the wall that divides the nasal cavity into two nostrils?
The nasal septum
What is the nasal septum made out of?
It is made out of the:
-vormer
-perpendicular plate of the ethmoid bone
-cartilage
What is the Vomer bone?
It is the flat bone forming the lower part of the nasal septum
What is the maxilla?
It is the upper jaw bone
What is the maxilla?
It is the upper jaw bone
What process of the maxilla houses the upper teeth sockets?
The Alveolar Process
What is the opening in the mandible for nerves and blood vessels?
The mental foramen
What is the superior orbital fissure?
It is the slit between the greater and lesser wings of the sphenoid.
What is the small bone that forms part of the eye socket and houses the nasolacrimal duct (tear duct) called?
The lacrimal bone
What bone is known as the cheek bone?
The zygomatic bone
What is the opening below the eye for blood vessels and nerves?
The infra orbital foramen
What is the primary salt of the bone matrix?
Calcium phosphate
What are Lacunae?
Lacunae are fluid filled pockets between layers of bone matrix that hold osteocytes
What are canaliculi?
They are tiny, fluid filled canals that connect the lacunae and allow osteocytes to communicate and spread nutrients to each other.
What is Ossification?
Ossification Is the process of creating bone either directly from embryonic connective tissue or indirectly using a cartilage model
What are the two types of ossification?
-Intramembranous ossification
-Endochondral ossification
What is intramembranous ossification?
Connective tissue condenses into a soft connective tissue sheet or membrane. Osteoblasts secrete bone matrix into the membrane, directly changing it to bone.
What is the primary ossification center?
The primary ossification center is a center where a hyaline cartilage bone model begins to ossify.
Where does the primary ossification center form in bones?
It forms in the diaphysis of the bone in an area of the periosteum called periosteal collar
Between what ages does bone growth stop in most people?
Between the ages of 18 and 25
What is a process?
A prominent projection on a bone
What is a foramen?
A foramen is an opening through the bone through which blood vessels, nerves or ligaments pass through
What is a trochanter?
A relatively large process
What is a suture?
An interlocking line of union between bones
What is a tubercle?
A small knob like process
What is a tuberosity?
A knob like process usually larger than a tubercle
What is a fossa?
A relatively deep pit or depression
What is an epicondyle?
A projection situated above a condyle
What is a condyle?
A rounded process that usually articulates with another bone
What is a crest?
A narrow, ridge like projection
What are the “soft spots” on an infants skull called?
They are called fontanelles
What is the purpose of fontanelles?
They are soft and moldable to assist with delivery through the birth canal.
What happens to the fontanelles as the babies grow?
The sutures begin to form between the bones
What is the large hole at the base of the skull called?
It is called the foramen magnum
What is the function of the foramen magnum?
It allows the spinal cord to connect to the brain.
What is another name for the external acoustic meatus?
It is called the ear canal
What is another name for the external acoustic meatus?
It is called the ear canal
What is the function of the mastoid process for mastoid process?
It serves as an attachment point for neck muscles that attach to the skull
What is the depression in the sphenoid where the pituitary gland sits called?
It is called the sella turcica
What are the smallest bones in the body?
The auditory ossicles
What are the bones of the auditory ossicles called?
-Malleus
-Incus
-Stapes
Where are the auditory ossicles located?
They are located in the middle ear cavities of the temporal bones
What is unique about the mandible?
It is the only movable bone in the skull
What is the joint that allows movement in the mandible called?
The temporomandibular joint (TMJ)
Where is the temporomandibular joint( TMJ ) found?
It is the articulation between the temporal bone and the mandible it is in front of the acoustic meatus
What is the cervical vertebrae?
The cervical vertebrae are the bones located in the neck. They are the smallest and lightest vertebrae.
How many bones make up the cervical vertebrae?
7
How many bones make up the thoracic vertebrae?
12
What are the thoracic vertebrae?
They are the posterior attachment for the bones of the ribs. The have spinous processes that you can feel when you run your finger down someone’s back
How many bones make up the lumbar vertebrae?
5
What is the lumbar vertebrae?
The lumbar vertebrae are the bones that make up the small of the back. They bear the most weight of all vertebrae.
How many bones make up the sacrum vertebrae?
5
What is the sacrum?
The sacrum is a triangular bone that consists of 5 fused vertebrae
How many bones make up the coccyx?
3 to 5 fused vertebrae.
What is the purpose of the coccyx in humans?
It is nonessential in humans
What are the two types of joints between the phalanges?
The proximal and distal interphalangeal joints (PIP and DIP)
What are the joints that join the proximal phalanges to the metacarpal bones?
Metacarpophalangeal joints
What is the largest tarsal bone in the body?
The calcaneus or heel bone
What are the joints that join the proximal phalanges to the metatarsal bones?
The metatarsalphalangeal joints (MTP)
Why is bone formation known as a replacement process?
It is known as a replacement process because as embryos develop, cartilaginous skeletons are replaced with bone during the ossification process.
What is a bone callus (p. Calli)?
It is a temporary bridge of cartilage and bone that forms across a broken bone to help it heal.
Describe the process of bone healing?
- A hematoma forms
- Internal and external calli form
- Osteoclasts resort dead bone
- Osteoblasts create new bone that replaces cartilage in the calli
- Calli eventually unite, remodeling occurs, and healing is complete.
What is the difference between modeling and remodeling?
Modeling allows bone to grow in diameter and remodeling occurs as bone is resorbed and replaced by new bone.
What is the functions of mechanical stress on bones?
It stimulates the deposition of mineral salts and collagen fibers within bones.
What is a caveat of calcium absorption in the human body?
Calcium cannot be absorbed from the small intestine if vitamin D is lacking.
What two vitamins may have a synergistic relationship when it comes to bone mineralization?
Vitamins K and D
What two elements play a supporting role in bone health?
Magnesium and Fluoride
What substance promotes the production of new osseous tissue and may reduce inflammation.
Omega-3 fatty acids
What is the function of growth hormone in bones?
It increases the length of long bones, enhances mineralization, and improves bone density.
What substance stimulates bone growth and promotes the synthesis of bone matrix?
Thyroxine
What function do the sex hormones play in bone growth?
They promote osteoblastic activity
The production of bone matrix
Which are both responsible for adolescent growth spurt, and promote closure of the epiphyseal plates
What stimulates the digestive tract to absorb calcium and phosphate?
Calcitrol
What hormone stimulates osteoclasts proliferation(rapid reproduction of cells)and resorption of bone osteoclasts?
Parathyroid hormone (PTH)
What are the additional functions of ParaThyroid hormone?
Promoting reabsorption of calcium by kidney tubules and indirectly increasing calcium absorption from the small intestine.
What inhibits osteoclasts activity and stimulates calcium uptake by bones?
Calcitonin
What is the optimal blood calcium level for homeostasis?
10mg/dL (miligrams by deciliter)
What is hypocalcemia?
Calcium Deficiency
What is hypercalcemia?
A condition in which the calcium levels in the blood become too high
What are the effects of hypocalcemia?
Hypocalcemia can result in problems with
-blood coagulation
-muscle contraction
-nerve functioning
-bone strength
What are the effects of hypercalcemia?
Hypercalcemia can result in:
-lethargy
-sluggish reflexes
-constipation
-loss of appetite
-confusion
-coma
Calcium homeostasis is controlled by what hormone, substances and vitamins?
-Parathyroid hormone
-Vitamin D
-Calcitonin
What organ systems control calcium homeostasis?
-Endocrine
-Skeletal
-Digestive
-Urinary
