Exam 2 Flashcards
1
Q
Cartilage
A
-very Firm gel
- 3 components: ground substance, fibers, ECM
- varies dependent on the ECM
2
Q
Chondroblast
A
- secretes the ground substance and the fibers
- cells become surrounded by the ECM they produce
- synthetic cell= make cartilaginous matrix
3
Q
Chondrocytes
A
- chondroblasts trapped in the ECM
4
Q
Lacuna(e)
A
- small spaces within the ECM where a cell resides
5
Q
Perichondrium
A
- outer structure made of dense CT
- has cells that look like fibroblasts
- innermost layer of these cells can form chrondroblasts
6
Q
Appositional growth
A
- cartilaginous matrix that gets added on the previous surface of the cartilage
> cartilage gets larger on the outside
7
Q
Interstitial growth
A
- involves cells in the core of cartilage-> cells become active again, divide, and form chondroblasts which form matrix in the core of the cartilage and displaces the older matrix
>growth from the inside
8
Q
Hyaline cartilage
A
- most abundant type of cartilage
- surfaces of long bones that make a joint-> ends of long bones
- found in joints, trachea, nose, etc
- in embryos= cartilaginous precursor to bone
- endochondral ossification
- composition= 70% bound water, 40% dry weight of fibers (Collagen 1), 60% GAGs
9
Q
Endochondral ossification
A
- how cartilage is turned into bone
10
Q
Fibrocartilage
A
- unusual cartilage (no perichondrium b/c not a discrete tissue)
- blend of dense CT and hyaline cartilage cells that produce matrix
-dense CT made of thick bundles of collagen 1 fibers which is made by fibroblasts - GS of sulfates GAGs
- location: spinal column (between vertebrates)
-resists compression and stretching
11
Q
Elastic cartilage
A
-matrix consists of a mix of elastic fibers and collagen type 2
-flexible
- found in external ear, epiglottis (near trachea)
12
Q
Bones
A
- cell +matrix (mineralized by hydroxyapatite which is phosphate and calcium
- 3 classification: long, flat, and irregular
- not homogenous
- light area= more dense
- dark area= less dense
- black= no density
13
Q
Compact (lamellar)
A
- type of bone tissue
- light area (found on the outer surface of the bone)
- dense
14
Q
Cancellous/spongy/trabecular
A
- type of bone tissue
- open, porous network
- honeycomb looking
- in the middle
15
Q
Long bone
A
- shaft is called the diaphysis (has 1 in the middle)
> largely hollow in adults - knobby part at the ends are called the epiphysis (2)
- as we age spongy bone is removed from diaphysis and moves towards the epiphysis
- marrow cavity (medullary cavity)
> yellow marrow=white fat & red marrow=blood forming tissue in spongy bone (hematopoietic)
16
Q
Irregular bones
A
- ex: vertebrate, pelvic bone
- pelvic girdle is a common source of tissue for marrow transplants
17
Q
Flat bone
A
- ex: bones of the craniun
18
Q
Epiphyseal line
A
- narrow lone of bone that spans across each epiphysis inside adult long bones
19
Q
Periosteum
A
- dense fibrous CT
- adhesive to the compact bone by type 1 collagen “sharpey’s fibers”
- becomes a component to the bone matrix that helps muscle attach to bone
20
Q
Organic part of bone
A
- cells + matrix
> the matrix is the critical differing part of bone as tissue cells are negligible - matrix of bone -> osteoid= type 1 collagen + GS
> primary component is fibers- collagen type 1
> 60% of osteoid is Collagen 1, 40% is GS
> GS is a firm gel
21
Q
Inorganic part
A
- calcium and phosphate (hydroxyapatite)
- transforms the osteoid into bone through ossification
- extracellular fluid= keeps ECM wet
> vehicle by which all our cells get nutrients and oxygen and aids in delivery of calcium and phosphate to osteoid
-osteoblasts are cells that make osteoid, initiate the formation of hydroxyapatite, and secrete membrane bound matrix vesicle into the matrix (50nm)
22
Q
Story of bone
A
- Bone formation= begins in utero
- Bone remodeling= maintenance, can happen at the same as formation, and happens for our entire lives
23
Q
Osteoprogenitor cell
A
- produce osteoblasts
- arise from the mesenchyme (CT stem cell)
- found on all surfaces of bone- even inside surfaces
- later stem cell- when stimulated, divides and differentiates into an osteoblast
24
Q
Osteoblast
A
- active cells, making of osteoid
- cytoplasm of these cells is PAS; indicator of carbohydrates and GAGs
25
Q
Osteocytes
A
- mature bone cells that re trapped within the matrix
- live within a lacuna
- were called osteoblasts when they were actively secreting
- have a low activity level but can become activated to perform small repairs; generally used for maintenance
26
Q
Osteoclasts
A
- bone remodeling- break down one
- influenced and stimulated by hormones
27
Q
Embryological origin of bone
A
- Intramembranous bones- aka membrane bones, dermal bones
> bones of the cranium, face, clavicle (flat bones)
> formed from an embryological membrane that was ossified - Endochondral bone
> arise from a cartilaginous precursor- hyaline cartilage transforms to bone
28
Q
Bone growth
A
- grows in length and girth
- lengthwise growth
> growth by turning cartilage into bone- ossifying cartilage (endocrhondral ossification)
> epihpyseal growth plate
29
Q
Skeletal muscle
A
- muscle fiber = muscle cell
- myofiber
- long cylindrical cells that are the same length of the muscle
- muscle cells are long, parallel cylinders having the same orientation as the muscle they are a part of
- cell diameter is variable btwn 10-100 nm
> different kinds of muscle cells have different diameters
30
Q
Skeletal muscle (part 2)
A
- multinucleated cells= syncytium that gets punched out to peripher
- external lamina
> surrounds each cell like a sleeve -> in orange on diagram; covering covering over the cell membrane and is similar to structure of a basement membrane - 2 types of fibers over the external lamina w/periodicity which form the endomysium
> (1) collagen type 1-larger
> (2) reticular fiber (collagen type 3)- smaller
31
Q
Muscle 2
A
- endomysium= muscle specific term
- sarcolemma= refers to cell membrane and its external lamina
> sarcoplasm (cytoplasm of the muscle cell)
> sarcoplasmic reticulum
~ smooth ER, branching yellow and pink parts of the diagram
~ surrounds cylindrical bundles of filamets
32
Q
Muscle 2 (part 2)
A
- myofibril= bundles are the same length of the diagram
> component of myofiber - sarcoplasmic reticulum units
> think about things stacked on a finger that are attached to each other
> upper and lower edges of the SRUs are continuous bonds terminal cisternae - terminal cisternae
> cistern- vessel for holding water
> cavity within SRUs- hollow, membranous organelle
33
Q
Muscle 2 (part 3)
A
- transverse tubules (T-tubules)
> invagination of the cell membrane forms a tubule
> go all the way around the cell surface
> form a branching network that is perpendicular to the cell surface
> dist from one set to another is uniform within a plane
> dist btwn 1 set to another is larger when moving down the surface of the cell
> dist changes are b/c of the different sized sarcoplasmic reticulum unistriad: group of 3 closely arranged structures
34
Q
Nervous tissue
A
- Nervous tissue-> nervous system (NS)
- works in conjunction with the endocrine system(ES) to create the communication network
*Nature of communication - if we have cellular activity in a given location, it ends up causing some appropriate cellular response at another location
- NS: uses electrical messages (action potential) ->nerve cells (responses immediate and short)
- ES: chemical messages (hormone) -> circulatory system (responses delayed and long lasting)
35
Q
Organization of nervous system
A
- Central nervous system (CNS)-> brain and spinal cord
- Peripheral nervous system (PNS)-> ganglia, nerves, and receptors
36
Q
Peripheral nervous system
A
- classified using a variety of criteria
- initial classification: based on function and relationship to CNS
1. carries messages to CNS -> afferent NS (sensory)-homogenous
2. receives messages from CNS -> efferent NS (motor) - heterogenous
37
Q
Efferent NS
A
- Classification based on type of tissue innervated
1. Somatic NS -> innervates skeletal muscle- voluntary (homogenous)
2. Automatic NS -> smooth/cardiac muscle, glands - involuntary (visceral) (heterogenous)
38
Q
Automatic NS
A
- classification based on location and function
1. Sympathetic NS -> location: mid spinal cord, function: stress
2. Parasympathetic NS -> location: upper and lower spinal cord, brain stem; function: resting activities, regular body function
39
Q
Nervous tissue (part 2)
A
- classification bases on function
1. Nerve cells = carry action potential
2. Supporting cells= support nerve cells (glial cells) - NT = nerve cells + glial cells
40
Q
New terms for NT
A
- neuron= nerve cell (we have 10 billion in our bodies)
- fiber = refers to the axon part of a nerve cell
41
Q
Classification of neurons based on location (relative to CNS) and function
A
- Motor neurons (efferent in nature)
> CNS -> effector (structure gives response) - Sensory neuron (afferent in nature)
> carry messages to CNS from the periphery where there is a sensory receptor which generates an AP - Inter neurons (association neurons)
> most abundant, all but 0.1%
> found in CNS
42
Q
Nerve cell communication
A
- neurotransmitters: acetylcholine(Ach) and norepinephrine (NE)
- somatic NS = only has Ach
- automatic NS
> sympathetic = both Ach and NE
> parasympathetic = only Ach
43
Q
Classification of neurons based on # of processes on cell body
A
- Multipolar (most abundant)
> 1 axon and 2 or more dendrites - Bi polar (found in places with special senses)
> 1 axon and 1 Dendrite - Pseudo-unipolar
> 1 axon (with 2 branches) and 0 dendrites
Where to find these?
> motor neurons and inter neurons= multipolar
> sensory neurons= pseudo-unipolar
44
Q
Genesis of Intramembranous bone
A
- Begins 4 weeks post conception- emergence of mesenchyme (CT stem cells)
> these cells migrate to locations in the embryo where the Intramembranous bones will form - 8 weeks after conception- aggregate and form an embryological membrane (sheet of cells roughly in the form of the bone that is forming- mostly flat bones)
45
Q
Genesis of Intramembranous bone (part 2)
A
- Mesenchyme cells begin to divide and differentiate and we get the formation of osteoblasts
> osteoblasts secrete osteoid and spongy/compact bone are eventually formed
> around the same time, blood vessels invade the forming spongy bone tissue and red marrow (diploe) forms within the bones - Mesenchymal cells can also form osteoprogenitor cells, and those osteoprogenitor cells go on to produce osteoblasts
> osteoprogenitor cells line outer and inner surfaces of developing bone and differentiate into osteoblasts which produce osteoid
> appositional growth
46
Q
Genesis of endochondral bone
A
- Mesenchymal cells in the embryo migrate to where Intramembranous and endochondral bones form point where 2 processes diverge
> rather than forming an embryological membrane, the cells form a grouping that is roughly the shape of the long bone it will be - Differentiate into chondroblasts instead of osteoblasts- about 8 weeks after conception
> activate cells that make cartilaginous precursor- tiny cartilage model of a future long bone it will be
47
Q
Genesis of endochondral bone (part 2)
A
- Cartilaginous precursor- 9 weeks after conception
> made specifically of hyaline cartilage
> has a perichondrium
> after precursor is formed, the bone grows in length and girth (appositional and interstitial growth) - Osteoblast formed- happens about 10 weeks after conception
> periosteum instead of perichondrium
> only involves part that will become eventual diaphysis of bone- epiphyses keep their perichondrium
> osteoblasts secrete a layer of osteoid
48
Q
Genesis of endochondral bones (part 3)
A
- Periosteum
> osteoblasts make osteoid which covers diaphysis part of precursor - Bony collar formed
> osteoid convering diaphysis part of precursor
> layer of bone over cartilage causes cells under the bony collar to suffer and swell inside their lacunae b/c they cannot get nutrients through diffusion - Cells under bony collar begin to secrete alkaline phosphate when under stress
>alkaline phosphate-enzyme that initiates formation of hydroxyapatite in bone; turns osteoid into bone
49
Q
Genesis of endochondral bone (part 4)
A
- Calcification
> alkaline phosphate causes calcification of the matrix and makes a barrier to diffusion - Chondrocytes die and disappear
> thin walls of the cartilage matrix are formed (spicules)
> vacant lacunae get larger b/c matrix deteriorates-looks like spongy bone but isn’t b/c its made of cartilage
> main component of bone matrix is collagen type 1 and it stains pink w/ H+E stain; cartilage stains blue - 2 concurrent events
>1. Blood vessels create holes in the bony collar through diaphysis & invades the newly formed cartilaginous matrix
>2. Mesenchymal cells migrate into diaphysis through the same hole that was formed by the blood vessels
50
Q
Genesis of endochondral bone (part 5)
A
- Mesenchyme cells divide and differentiate into osteoprogenitor cells which line cartilaginous surfaces
> osteoprogenitor cells divide and form osteoblasts
> osteoblasts -> osteoid
> mixed spicules: 2 parts
>1. Acidophilic part (pink)- bone
>2. Basophilic part (blue)- cartilage matrix core
> cartilaginous matrix core disappears and osteoblasts fill the space with osteoid - Cartilage -> spongy bone
- Stem cells from blood -> red marrow
> adult: diaphysis have a medullary cavity w/ yellow marrow - Bone resorption- removal of spongy bone in adult
> by osteoclasts: related to monocytes
> mononuclear phagocytic system- macrophages of various types
51
Q
Bone growth
A
- grows in length and girth
- lengthwise growth
> grows by turning cartilage into bone- ossifying cartilage (endochondral ossification)
> epiphyseal growth plate- where the epiphysis meets the diaphysis
52
Q
Epiphyseal growth plate zones
A
- Zone of reserve cartilage
- Zone of proliferation
> cells begin to divide, become synthetically active, and making cartilaginous matrix
> stacked in columns - Zone of hypertrophy
> cells are enlarging&filling the lacunae in which they reside - Zone of degeneration
> cells are secreting alkaline phosphate which causes calcification of the matrix
> holes and gaps created in the matrix - Zone of resorption
> osteoblasts lining the surfaces of enlarging gaps and holes; secreting osteoid
> forming bone from mixed spicules
> blood vessels invade the area
53
Q
Primary and secondary ossification
A
- Primary ossification= formation of spongy bone in the diaphysis due to the bony collar- happens before birth
- secondary ossification= happens at different times b/c we have 2 epiphyses for each long bone
> proximal end of a bone does ossification first (end closer to body)
> distal ends ossify later (end farther from body)
> occurs after birth
> areas of cartilage still exist- articulate surface (cartilage that forms our joints)
54
Q
Bone remodeling
A
- combined process that includes removal and replacement of bone
- main cell in this process= osteoclast
> large, multinucleated cell
> often hidden away in surfaces of bone when inactive
> activity controlled largely by the levels of parathyroid hormone and the secretion of cytokines from osteoblasts - organic part of bone is osteoid (GS) and fibers; inorganic part is hydroxyapatite
55
Q
Bone remodeling (part 2)
A
-osteoclasts have 2 categories of secretion
1. Carbonic acid: removes hydroxyapatite
> dissociates into bicarbonate and hydrogen ions
> H^+ ions are removed from the cell by proton pumps and are pumped out of the cell to the bone surface where the acidity breaks down the hydroxyapatite- once gone, organic part if vulnerable
2. Enzymes: including cathepsin k which attacks fibers; GS attacked by other enzymes
56
Q
Bone remodeling (part 3)
A
- pit/hole created in the bone is called the Howship’s lacunae
> compelling to osteoblasts- don’t want holes so they will line the surface of the Howship’s lacunae and create a layer of osteoid (lamella)
> osteoblasts then come in again and line the first lamella with more osteoid, however in another direction-> repeated over and over again
>small gap in the middle where blood vessels and nerves will be- Haversian canal
> whole structure is an osteon
