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Flashcards in CH.6 Deck (62)
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1
Q

Why are bones organs?

A

because they contain compact bone tissue, connective tissue, bone marrow, blood.

2
Q

Why is the skeletal system a system?

A

because contains bones which contain multiple tissue types, cartilages which contain multiple tissue types (perichondrium), joints are formed from more than one bone and connective tissue types that make them into joints.

3
Q

What is cartilage, what is its matrix made of, and what is the predominant cell type?

A

connective tissue, avascular, extracellular matrix contains fibers and is gel like,the predominant cell type are chondrocytes that sit within lacunae in the extracellular matrix.

4
Q

What is hyaline cartilage made of and what is its function and locations in the body?

A

Mainly collagen fibrils (small reticular fibers, has a glassy look)
Function is to give resiliency and shock absorption
Locations: ends of long bones, embryonic skeleton, costal cartilages, epiphyseal plates, respiratory structures (trachea, nose, bronchial tubes).

5
Q

What is elastic cartilage, function, and locations in the body?

A
Mainly elastic (thin, densely packed, very darkly staining) fibers
Function: elastic, has the ability to recoil or spring back into shape following deformation.
Locations: epiglottis, outter ear.
6
Q

What is fibrocartilage, function, and loactions in the body?

A

shock abosrption, very strong because of the abundance of collagen fibers
locations: intervertebral discs, pubic symphisis, menisci in the knee joint

7
Q

Why are the cartilages of the skeletal system considered organs?

A

because of the perichondrium

8
Q

what is the perichondrium and function?

A

peri= around
made of dense irregular connective tissue proper
typical cartilages of the skeletal system will be surrounded by this CT.
Function: acts like a girdle for the cartilage and provides a little bit more strength and resiliency so when the cartilage is squished it will be able to spring back better.
this is vascular so it also functions in growth and repair.

9
Q

When does cartilage grow and what are the two types of growth?

A

Grows in adolescence

appositional and interstitial growth.

10
Q

What is appositional growth?

A

Found along the outskirts of the cartilage there will be chondroblasts that are in between the cartilage and perichondrium but part of the perichondrium that will secrete matrix and cause growth from the outside.

11
Q

What is interstitial growth?

A

Chondrocytes found deep within the tissue divide and produce new cells and secrete new matrix.
it is a growth from within
this stops in adults but the chondrocytes remain to take care of the tissue but do not not grow any longer.
hence why cartilage in adults has a poor repair or regenerative ability.

12
Q

What are the functions of bones?

A

Support, protection, movement,
mineral storage: bones are made up of collagen fibers that contain minerals that have crystalized on the fibers. can be released into the body if the diet is lacking certain minerals like calcium.
Hemopoesis: red bone marrow helps with the production of red blood cells.
energy storage: bones contain yellow bone marrow in the core which is mainly adipose tissue
metabolism: bones release a hormone that determine how well you metabolize lipids, so it plays a role in how well your cells utilize nutrients for work.

13
Q

What are long bones?

A

have a skinny midportion and very distinct ends
has nothing to do with size
example: phalanges, femur, tibia, fibula, clavicle

14
Q

What are short bones?

A

cube like, as in they are about the same size around the bone.
exmaples: carpal bones, tarsal bones

15
Q

What are sesamoid bones?

A
another class of short bones
tiny bones that develop within a tendon
function: change the direction of pull at a particular joint. 
(patella is the larger of the sesamoid bones)
another example are two tiny bones that are unerneath the ball of your foot and they sit in the tendons that cross the ball of your foot. help with change of direction of pull of your big toe during  plantar flexion and extension.
16
Q

what are irregular bones?

A

Irregular shaped

examples: vertebra oxcoxae

17
Q

What are flat bones

A

Flat

scapula, skull, ribs, sternum

18
Q

What is the metaphysis?

A

junctional area where the diaphysis meets the epiphysis and contains the epiphyseal plate/line

19
Q

What are the regions of a long bone?

A

Diaphysis (shaft)
epiphysis (ends)
Metaphysis

20
Q

What is the epiphysis?

A

The distal/proximal ends of a long bone.
Contains more spongy bone tissue than compact bone tissue
contains articular cartilage (hyaline)

21
Q

What is the diaphysis?

A

The shaft of the bone.
Contains nutrient arteries running alongside the bone against the periosteum where they will cut through this conenctive tissue and dive straight into the bone via a nutrient foramen.
wall is mainly compact bone tissue but there is spongy bone tissue lining the medullary cavity.

22
Q

What is a nutrient foramen?

A

Allows the nutrient arterties to dive into the bone and then send its branches to individual central canals of osteons.

23
Q

What is anchoring the periosteum to the compact bone tissue?

A

Sharpeys fibers, perforating collagen fiber bundles.

24
Q

Where are sharpeys fibers found in abundance?

A

where muscles attach to bones

25
Q

Why do we get bumps on bones?

A

Because at the sites where the tendons of the muscles attach to the bones there is a lot of pulling on the compact tissue and we get a bump because the sharpeys fibers are yanking on the compact tissue causing it to grow to help accomadate for the pulling

26
Q

What is the basic anatomy of short, irregular, and flat bones?

A

They have a continuous layer of compact bone tissue and filling up the entire inside there is spongy bone tissue.

27
Q

What is the periosteum & describe its layers?

A

Attached by sharpey’s fibers
Thick membrane that covers the external compact bone tissue. Does not cover the articular cartilage at the epihyseal regions. goes up to it and stops.
Superficial layer= dense irregular CT proper
Deep layer= osteogenic layer —> contains both osteoblasts and osteoclasts. mainy called this because it has the ability to produce new bone cells but DO NOT forget that is can also break down bone cells in this layer.

28
Q

What is endosteum?

A

connective tissue
lines the internal bone surfaces
-lines the central canals of osteons, covers ALL spongy tissue inside all bones (medullary cavity, epiphysis, and spongy bone tissue inside short, flat, irregular bones.)
Thin membrane that is osteogenic (contains both osteoclasts and blasts)
highly vascular

29
Q

What do bone markings represent?

A

the surface of a bone reflects the stresses applied to specific locations.
examples: projections, joint surfaces, depressions and openings

30
Q

What is another name for an osteon?

A

haversian system

31
Q

What is interstitial lamellae?

A

Not whole rings, just filling up the space between osteons

32
Q

What is the compact tissue unit?

A

the osteon

33
Q

How do arteries and nerves travel in the spongy tissue?

A

around the trabeculae

34
Q

What is another name for Volksman’s canals and what is the function?

A

Perforating canals; allows the central canal of one osteon to have access to the central canal of the adjacent osteon. this allows vessels and nerves to reach further and further into the bone tissue.

35
Q

In what direction to osteons run along bones?

A

Along the long axis of the bone.

36
Q

What are canaliculi (canaliculus single) and their purpose?

A

Small channels between in the lamellae, inside the hardened bone matrix, that allow the processes from osteocytes to go in and make contact with outer osteocytes to send oxygen and nutrients to the outer osteocytes.

37
Q

What type of junctions will you find in canaliculi?

A

Lots of gap junctions for metabolic coupling

38
Q

What is the arrangement of collagen fibers in the lamellae?

A

They are all running parallel with one another in the same lamellae but in different lamellae they are running about 90 degrees from one another.

39
Q

What is the advantage of the arrangment of collagen fibers osteons have?

A

This allows an individual osteon to have an enormous amount of strength and give the bone a lot of strength and resilience against twisting or bending types of forces.

40
Q

How does bone matrix solidify?

A

Collagen fibers act like rebar in construction…
the collagen fibers are laid down and then all of the mineral salts start to crystalize along the length of the collagen fibers causing for an already strong type of fiber to be extra strong with mineral salts crystalized on them. gives the resiliency of bone tissue.

41
Q

What does trabecula (trabeculae plural) mean?

A

little beam

42
Q

How do trabecula receive their nutrients and oxygen?

A

via the vascularized endosteum that contains capillaries

43
Q

What is the difference between a trabecula and an osteon?

A

Trabeculae are completely solid in the inside whereas osteons have central canals.
trabeculae are completely covered in endosteum (osteogenic layer of connective tissue) whereas only the central canal of the osteon is lined with endosteum.

44
Q

What is found in the spaces between trabecula?

A

Red bone marrow

45
Q

Do trabeculae have osteocytes?

A

Yes, within lacunae.

46
Q

What is osteogenesis or ossification?

A

The process by which bone forms

47
Q

What are the four scenaries in which bone forms?

A
  1. formation of bones in embryo
  2. growth of bones in adulthood
  3. remodeling of bones throughout life
  4. repair of fractures (good regenerative capacity)
48
Q

How do bones get longer? 2 steps

A
  1. Cartilage growth on the epiphysis side of the epiphyseal plate
  2. Replacement of cartilage by bone on the diaphysis side
49
Q

What happens to the process of bone lengthening when adolescence comes to an end?

A

The epiphysis stop secreting chondroblasts and the the epiphyseal plates close and all the cartilage is replaced with bone tissue leaving a bony structure called the epiphyseal line.

50
Q

How do bones get wider?

A

Involves getting a larger meduallary cavity but having the same thickness to the diaphysis wall.

  • –Osteoblasts from the periosteum add bone tissue to the circumferential lamellae
  • –Osteoclasts from the inner diaphyseal wall remove bone tissue at about the same rate
51
Q

How often is bone remodeled?

A

Spongy bone- 3-4 years

compact bone- 10 years

52
Q

Why is bone remodeled?

A

response to mechanical stresses
-muscles pulling a certain way, bumping into the things
homeostasis of calcium and phosphate levels in body fluids
-bones store calcium and phosphate so in times when our diet does not bring in enough of those minerals, osteoclasts break up bone tissue releasing calcium ad phosphate.

53
Q

How does bone resorption work?

A

Osteoclasts secrete HCl and lysosomal enzymes.
-HCl dissolves the mineral salts and the enzymes help break down the collagen fibers, the cells themselves (organic material).
-collagen fibers and dead osteocytes are then phagocytosed.
The Calcium ions are then released and enter the interstitial fluid and since this is happening in the osteogenic layers (such as the endosteum and the deep layer of the periosteum) there are lots of capillaries because these areas are highly vascularized, so the calcium ions then enter the blood.

54
Q

Are osteoclasts multinucleate?

A

yes, same as skeletal muscle

55
Q

Why do osteoclasts have ruffled borders?

A

to increase surface area
the more surface area —> the more area the osteoclasts can cover and secrete lysosomal enzymes/HCl onto the bone tissue.

56
Q

When does bone deposition occur?

A

When the bone is injured or there is added demand placed on the bone (like high impact exercises—> causes bones to increase bone mineral density)

57
Q

What is essential in order for new bone tissue to be laid down?

A

Calcium from the diet. osteoblasts may want to respond but it wont if there is not enough calcium

58
Q

When do osteoblasts become osteocytes?

A

When an osteoblast has built itself inside of a lacunae and has completely enveloped itself in its own extracellular matrix and can no longer add bone tissue but now it just upkeeps the tissue around it.

59
Q

How are cracks in stressed bones reduced in the body?

A

mineral salt crystals pack together in a pattern that reduces the risks of cracks in stressed bones.

60
Q

What are the two types of osteogenesis (ossifcation)?

A

Intramembranous and endochondral

61
Q

What is intramembranous ossification?

A
  • Bone forms directly from mesenchyme that is pancaked down and placed in layers that resemble membranes
  • exmaples: most skull bones and the clavicles
62
Q

What is endochondral ossification?

A

-within cartilage ossification-
the bone forms within hyaline cartilage, replacing the cartilage
all bones from base of skull down except for the clavicles are made this way.