AN120: Lesson 3 Flashcards
The 4 Functions of the human skeleton
- Body Support
- Protection
- Motion
- Formation of blood cells (hematopoiesis)
How does the skeleton support the body?
It provides a framework for the human body
What is an example of the skeleton protecting soft structures?
The skull which surrounds the brain
How do bones allow for motion?
Muscles are attached to them and moves them. The bones are what provide leverage for motion.
Where does hematopoieses occur?
In red bone marrow, mainly in flat bones.
What organs do the ribcage and sternum protect?
They protect the thoracic cavity’s viscera as well as the upper abodominal viscera
Define Bone
A hard connective tissue that consists of cells, fibres, and matrix.
What makes bone hard?
Calcification of its ECM
What makes bone have a degree of elasticity?
The organic fibres.
2 Forms of Bone:
with definition
- Compact bone (appears as a solid mass)
- Cancellous bone (spongy appearance)
What are trabeculae?
and their function
Trabeculae are the branching networks that gives cancellous bone resistance against mechanical stresses and strains
Which cell breaks down old bone tissue
Osteoclasts
Which cell forms new bone tissue?
osteoblasts
Important to note
What are bones composed of?
- an exterior cortex
- an interior network, filled with blood vessels and marrow
Define osteoclast
Break down old bone tissue to make room for new, healthier tissue to replace it.
What are the structural levels of bone?
- Cortex
- Medulla
- Marrow
Define osteocytes
Cells responsible for maintaining bone growth and density
What is the outer layer of bone?
Cortex
Define Cortex
Outer layer of bone made up of compact/dense bone tissue and is covered with periosteum.
What is the inner portion of bone?
Medulla
Define Medulla
Inner portion of the bone that consists of cancellous/ spongy bone tissue.
What is unique about the medulla in some bones?
and in which bones
Particularly in long bone, the medulla has a hollow space with no bone tissue.
- It is called the medullary/ marrow cavity.
Define Marrow
Serves as a filler inside of bones
Types of Marrow
- Yellow
- Red
What is yellow bone marrow
It is mostly yellow fat tissue.
What is red bone marrow
The only site in adults for formation of RBCs.
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true dat
T/F
Red bone marrow is the only site for hematopoiesis in children.
False, it is the only site for RBC formation in ADULTS.
from internal to external, label the layers of this bone.
- Medullary cavity
- Endosteum
- Cancellous bone
- Compact bone
- Periosteum
Where is red and yellow bone marrow located in long bone of adults?
red: it is only at the extremities of the bone
yellow: found in the shaft’s medullary cavity
Term for bone formation:
ossification
Types of ossification based on the type of bone
- ossification of membranous bones
- ossification of cartilagenous/ endochondral bones
Mechanism of membranous bone ossification:
- osteoblasts invade membrane
- form a centre of ossifcation
- bone-forming activity spreads out from centre
- full bone is formed
Example of membranous bone ossification is:
the bones of the skull
How do bones of the skull develop and what is the final product?
explain why
After undergoing membranous bone ossification for the cranial bones, small areas of membrance persist between these bones even at birth.
- these regions of membrane between bone allow for bone mobility so that the skull can mold during descent at birth from female genital passages.
How do endochondral bones ossify?
and age its completed
Cartilagenous bones first exist as models made of cartilage (cartilagenous anlagen).
- it starts as a cartilagenous model in the fetus and by 18-20, these bones would have completed their ossification.
What type of ossification do long bones undergo?
Endochondral/ cartilagenous bone ossification.
How old must one be to have completed cartilagenous bone formation?
18 to 20 years old
Which bones undergo endochondral ossification?
All bones of the skeleton below the base of the skull, EXCEPT FOR CLAVICLES (they are membranous ossification)
Define Ossification Centres
They are a growing mass of actual bone within the pre-formed material.
Initial Bone formation:
endochondral ossification
Involves the destruction of pre-forming material and replacement with bony tissue
What are the types of ossification centres in long bone?
- Epiphyseal
- Diaphyseal
What is the diaphysis?
It is the centre of bone formation in the shaft of bones.
What is the epiphysis?
It is the centre of bone formation at the ends of the bone.
What is in between the epiphysis and diaphysis?
A plate of cartilage called the epiphyseal plate.
What is the metaphysis?
It is the part of the diaphysis close to the epiphyseal plate.
Types of bones is determined by…
their construction pattern
What are the types of bones?
with example
- Long (humerus)
- Short (carpal bones)
- Flat (cranial frontal bone)
- Irregular (vertebra)
- Sesamoid (patella in knee)
Where are rough or raised surface markings of bone found?
In the regions of attachment on bone for bands of…
- fascia
- ligaments
- tendons
- aponeuroses
Are these roughenings present at birth?
No, they appear at puberty and become more obvious during adult life.
How does the body make new room for bone?
Fibrous structures attached to bone pull periosteum so new bone deposits underneath.
Condyles and epicondyles are considered…
expanded ends
Define
Condyle
- rounded, knuckle-like articular area
- often in pairs
What are types of surface markings of bone?
- Condyles (medial & lateral femoral condyles)
- Epicondyles (lateral epicondyle of the humerus)
- Crest (iliac crest)
- Facet (superior costal facet on the body of a vertebra)
- Foramen (obturator foramen)
- Fossa (infraspinous fossa of scapula)
- Groove (radial groove of humerus)
- Head (head of humerus)
- Line (soleal line of tibia)
- Malleolus (lateral malleolus of fibula)
- Neck (no ex.)
- Process (spinous process)
- Shaft (no ex.)
- Spine (scapular spine)
- Trochanter (greater trochanter of femur)
- Trochlea (trochlea of humerus)
- Tubercle (greater tubercle of humerus)
- Tuberosity (ischial tuberosity)
Define
Crest
ridge of bone
Define
Epicondyle
eminence superior or adjacent to condyle
Define
Facet
smooth flat area, usually covered with cartilage.
- where bone articulates with another bone
Define
Foramen
passage through bone
Define
Fossa
hollow or depressed area
Define
Groove
elongated depression or furrow
Head
large, round articular end
Line
linear elevation
- sometimes called a ridge
Malleolus
rounded process
Neck
relatively narrow portion adjacent to head
Shaft
the diaphyis (body) of long bone
Spine
thorn-like process
Trochanter
large blunt elevation
Trochlea
spool-like articular process
- or process that acts as a pulley
Tubercle
A small raised eminence
Tuberosity
large round elevation
When is deformity visible in bone fractures?
When the bone fragments have been displaced from one another
What is the degree and direction of deformity affected by?
The pull of the muscles attached to the fragments
What does fracture cause?
hemorrhage of blood between bone ends and into the surrounding soft tissue.
What parts are involved in the repair process of bone fractures?
- blood vessels
- fibroblasts
- osteoblasts
all from the periosteum and endosteum
What are features of the female body?
- Shorter
- More subcutaneous fat in: breasts, buttocks, and thighs
- Wider pelvis than male
- Head hair is finer
- Skin smoother in appearance
- Pubic hair does not extend to umbilicus
What are features of the male body?
- Taller and longer legs
- Bigger and heavier bones
- Larger muscles
- More angular appearance
- Larger larynx and longer vocal cords (deeper voice)
- Heavy body hair and pubic hair extends to region of umbilicus
Up till what age does growth have the same rate?
up to 10 years old
At what age do boys visibly start to grow faster than girls?
At around 12 years old, boys often start to grow faster than girls, so that most males reach a greater adult height than females
What is cartilage?
- form of CT
- gel-like matrix with fibres and cells embedded
What does the gel-like matrix of cartilage do?
give it firmness and resilience
What covers cartilage and where is it found?
The perichondrium; on all cartilage except that of exposed surfaces in joints
What are the 3 types of cartilage?
- hyaline
- fibrocartilage
- elastic cartilage
What is hyaline cartilage?
- has a high proportion of amorphous matrix
- plays important role in length growth of long bones in youth
- has great resistance to wear
- covers articular surfaces of nearly all synovial joints
- defects in hyaline are filled with fibrous tissue
Can hyaline cartilage repair itself?
no, only fibrous tissue in defect
Which cartilage has great resistance to wear?
Hyaline cartilage
How is hyaline cartilage important in length growth of long bones?
the epiphyseal plates are composed of hyaline cartilage
Properties of fibrocartilage?
- many collagen fibres embedded in a small amount of matrix
- found in the discs within joints
- if damaged it slowly repairs in a manner similar to fibrous tissue
- the joint discs however DO NOT repair themselves when damaged
Example of fibrocartilage
the disc in temporomandibular joint
TMJ
Why can’t discs in joints repair themselves?
Have poor blood supply.
What is Elastic cartilage?
- has large numbers of elastic fibres (elastin) in matrix
- flexible
What are examples of elastic cartilage?
- aruicle of the ear
- external auditory meatus
- eustachian tube
- epiglottis
Where is elastic cartilage found?
- found in auricle of the ear
- external auditory meatus
- auditory tube
- epiglottis
Can elastic cartilage repair itself?
No, only with fibrous tissue.
What do hyaline and fibro- cartilage have in common?
They both tend to calcify or even ossify later in life.
Define joints
- site where 2+ bones come together
- may or may not move
How are joints classified?
By the type of tissue that lies between the bones
What are the types of joints?
- Fibrous
- Cartilaginous (primary and secondary)
- Synovial
Define fibrous joints
- articulating surfaces of the bones are joined by fibrous tissue
- very little movement
Examples of fibrous joints
- the sutures of the vault of the skull
- inferior tibiofibular joints
What are primary cartilaginous joints?
(synchondrosis)
- bones united by growing plate of hyaline cartilage
- no movement
Example of 1ry cartilaginous joints (synchondrosis)
- between epiphysis and diaphysis of growing bone
- between 1st rib and manubrium
What are secondary cartilaginous joints?
- united by plate of fibrocartilage
- thin layer of hyaline cartilage at the articular surfaces of the bone
- little movement possible
Example of 2ry cartilaginous joints:
- between the vertebral bodies intervertebral disks
- symphysis pubis
List in order from interior to exterior the parts of synovial joints
- (sometimes) disc/ wedge
- cavity
- synovial fluid (produced by membrane)
- synovial membrane
- (occasionally) fatty pads
- fibrous capsule
- thin layer of hyaline cartilage on bones
What is an example of a synovial joint containing a disc?
Knee joints.
What is the disc in certain synovial joints made of?
fibrocartilage
What is an example of a synovial joint containing fatty pads?
hip and knee joints
Types of synovial joints:
with examples
- Plane (sternoclavicular joints)
- Hinge (elbow, knee, and ankle)
- Pivot (superior radioulnar joints)
- Condyloid (metacarpophalangeal joints aka knuckles)
- Ellipsoid (wrist)
- Saddle (carpometacarpal joint of thumb)
- Ball-and-socket ( shoulder and hip joint)
Which cartilage has amporhous matrix and what does that mean?
Hyaline cartilage; it has randomly arranged and intertwined structures
What limits the degree of movement in a synovial joint?
- shape of the bones participating in the joint
- coming together of adjacent anatomic structures
- presence of fibrous ligaments uniting bone
Where do most ligaments lie?
most are found outside joint capsule
- in knee, some are is within the capsule, like the cruciate ligament
What 3 factors does the stability of joints depend on?
- articular surfaces: their shape, size and arrangement
- ligaments
- tone of muscles around the joint
Example of articular surfaces affecting joint stability:
- the hip’s ball and socket arrangment
- mortise (“plug” in) arrangement of ankle joint
What are examples of joints where the shape of the bones contributes little/ nothing to their stability?
- acromioclavicular joint
- calcaneocuboid joint
- knee joint
Define bursa
- closed sacs/ envelopes of serous membrane
- normally collapsed
- walls are apposed with only a thin film of lubricating fluid
Where is bursa often location?
in locations subject to friction
- they allow one structure to move more freely over another.
Define ligament
and where
Cord/ band of CT uniting two structures
- commonly found in association with joints
Types of ligaments
- Fibrous
- Elastic
What are fibrous ligaments?
- dense bundles of collagen fibres
- unstretchable
- prevent excessive movement in joint
- continued stress for long periods can stretch these fibrous ligaments
What causes flat feet?
the impairment of muscles that support the arch due to 1) weight or 2) fatigue causes the ligament to stretch and hence collapse the arch.
What are elastic ligaments?
- made largely of elastic tissues
- can regain original length after stretching
Example of elastic ligaments
the elastic ligaments of the auditory ossicles play an active part in supporting the joints and assisting in the return of the bones to their original position after movement. (like a little spring)
