Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A & P I > Chapter 6 > Flashcards

Chapter 6 Flashcards

1
Q

Skeletal System

A

Includes:

  • Bones
  • Joints
  • Supporting Tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bones

A

Main Organ

Composed of - More Osseous tissue; Dense Regular, Dense Irregular Collagenous Connective Tissue, and Bone Marrow;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Functions of Bone

A
  1. Protection- Certain bones protect underlying organs; (Skull, Sternum, Ribs)
  2. Mineral Storage & Acid-Base Homeostasis- Storehouse for Calcium, Phosphorus, and Magnesium salts; Minerals present as electrolytes, acids, & bases
  3. Blood Cell Formation- Bone houses [red bone marrow]-> connective tissue involved in formation of blood cells [Hematopoiesis]
  4. Fat Storage- Bone also contains [Yellow Bone Marrow]-> made up of fat cells (adipose); Stores triglycerides; Fatty acids from breakdown of triglycerides can be used as fuel
  5. Movement- Bone serves as sites for attachment of most skeletal muscles; Muscles contract and pull on bones; (Generates Movement)
  6. Support- Skeleton supports weight of the body, providing its framework
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bone Structure:

[5 classes]

A

206 bones in human body

Long bones, Short bones, Flat bones, Irregular bones, & Sesamoid bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Long Bones

A
  • Overall shape, NOT size
  • Longer than wide
  • Includes most bones in Arms & Legs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Short Bones

A
  • Cube shaped
  • Long as they are wide
  • Includes bones of Wrist [Carpals] & Ankle [Tarsals]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Flat Bones

A
  • Thin & Broad

- Includes Ribs, Pelvis, Sternum, & Skull bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Irregular Bones

A
  • Irregular shape, so it doesn’t fit into other classes

- Includes Vertebrae & certain Skull Bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Sesamoid Bones

A
  • (usually) Small, Flat, & Oval shaped
  • Located within Tendons
  • Mechanical advantage of Tendons
  • Muscles have better leverage

Example: Kneecap [Patella]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Long Bone Structure

A
  1. Periosteum: Membrane composed of Dense Irregular Collagenous Connective Tissue; Rich with blood vessels & nerves; Surrounds outer surface of Long Bones
    - Perforating Fibers: Made of Collagen; Anchors Periosteum to underlying bone surface by penetrating deep into Bone Matrix
  2. Diaphysis: Shaft of Long Bone, Each end is Epiphysis; Covered with a thin layer of Hyaline Cartilage [Articular Cartilage], found within joints [Articulations] between bones
    - Hollow Cavity: [Marrow] within Diaphysis, containing Red or Yellow Bone Marrow;
  3. Compact Bone: One of Two bone textures: Hard or Dense Outer Region; Allows bone to resist linear compression & twisting forces; (1st BONE STRUCTURE)
  4. Spongy Bone: [Cancellous] inside Cortical Bone with a Honeycomb framework of bony struts; Allows Long Bone to resist forces from many directions, providing cavity for Bone Marrow (2nd BONE STRUCTURE)
  5. Endosteum: Bony strut of Spongy bone & Inner surfaces covered by thin membrane
  6. Epiphyseal Lines: Separates Proximal & Distal Epiphysis from Diaphysis; Epiphyseal plates [Growth Plates], Lines of Hyaline Cartilage found in bones of children
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Structure of Short, Flat, Irregular, & Sesamoid Bones

A
  • Does Not have Diaphysis, Epiphyses, Medullary Cavities, Epiphyseal Lines, or Epiphyseal plates;
  • Covered by Periosteum, Perforating fibers, Blood vessels, and Nerves
  • Internal Structure: Two outer layers of thin Compact bone with middle layer of Spongy bone [diploe] & associated Bone Marrow
  • Some Flat & Irregular bones of skull contains hollow, air-filled spaces, which reduces bone weight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Blood & Nerve Supply to Bone

A
  • Bones are supplied with blood vessels & sensory nerve fibers
  • Blood supply to Short, Flat, Irregular, and Sesamoid bones is provided by vessels in Periosteum that penetrate bone
  • Long bones get third of their blood supply from Periosteum; Supplies Compact Bone. The remaining 2/3 is supplied by 1-2 [Nutrient Arteries], Enters the bone through a small hole in Diaphysis [Nutrient Foramen]; Nutrient Arteries bypass Compact bone to supply internal structures of bone.
  • Epiphysis receives some blood supply from Nutrient Arteries, but majority comes from small blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Red Bone Marrow

A
  • Loose Connective Tissue that supports blood-forming hematopoietic cells;
  • Amount of Red Marrow decreases with age; In an adult, its located In Pelvis, Proximal Femur & Humerus, Vertebrae, Ribs, Sternum, Clavicles, Scapulae, & some bones of Skull
  • Children need (MORE) Red Marrow to assist in growth & development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Yellow Bone Marrow

A

-Triglycerides, Blood Vessels, & Adipocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Microscopic Structure of Bone Tissue

A

-Bone,[Osseous Tissue] : Primary tissue in the bone; Composed of ECM with scattered cells

-ECM of Bone: Unique
Inorganic Matrix- 65% of bones weight
Organic Matrix- remaining 35%; Consists of collagen fibers and ECM components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Inorganic Matrix

A
  • Calcium salts; Bones store 85% of total calcium salts, as well as Phosphorus
  • [CALCIUM & PHOSPHORUS]* -> salts exist as [Hydroxyapatite Crystal Ca10(PO4)6(OH)2]
  • Crystal structure makes bone (ONE OF THE ) hardest substances in the body; Strong & Resistant
  • Allows bone to be protective and supportive
  • Bicarbonate, Potassium, Magnesium, & Sodium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Organic Matrix

A
  • Consists of protein fibers, Proteoglycans, Glycosaminoglycans, Glycoproteins, and bone specific proteins;
  • Collagen: protein fiber that forms cross-links and helps bones to resist torsion & tensile forces; Collagen Fibers align with Hydroxyapatite Crystals, which enhances hardens of bone
  • Glycosaminoglycans & Proteoglycans create an Osmotic gradient, which draws water into Osteoid and helps tissue to resist compression
  • Glycoproteins in Osteoid, binds different components of Osteoid & Inorganic Matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Bone Cells

A
  • Dynamic Tissue; Always changing as old bone breaks down for materials to build new bone
  • 3 Types: Osteoblasts, Osteocytes, & Osteoclasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Osteoblasts

A
  • Active bone in Periosteum & Endosteum;
  • Osteogenic Cells: Flattened; Disperse into Osteoblasts when stimulated by chemical signals
  • Osteoblasts: Bone building cells; Bone deposition*
  • Bone Deposition: Osteoblasts secrete organic matrix materials; Assists in formation of Inorganic Matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Osteocytes

A
  • Osteoblasts surround themselves with Matrix in Lacunae; In return becomes Osteocytes that no longer synthesize bone matrix
  • No longer metabolically active (EXCEPT) for maintaining bone ECM; Appears to have the ability to recruit Osteoblasts to reinforce bone under tension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Osteoclasts

A

-Responsible for Bone Resorption; Cell secretes hydrogen ions & enzymes
(Break down bone matrix)
-Different overall cell shape than other two-> (Large Multinucleated Cells) Derived from fusion of cells from bone marrow
-Located in shallow depressions on the Internal & External surface of bone
-Hydrogen ions dissolve components of Inorganic Matrix; Enzymes break down Organic Matrix
-Substances from breakdown includes nutrients, minerals, amino acids, & sugars; Absorbed by methods into Osteoclast cytosol
-Substances can be released into blood, might be either reused or excreted from body as waste products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Histology of Bone

A

-Outermost Compact Bone & Inner Spongy Bone tissue;

Structure : *Stress; Tends to strain or deform objects like bone

                 * Compact bone resembles a forest of tight packed trees; Each tree represents a unit, [Osteon]
                  * Ring of each tree is made up of [Lamellae]-> thin layers of bone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Osteon Structure

A
  • Each Osteon contains 4-20 Lamellae arranged in layered structures, [Concentric Lamellae]
  • Lamellar arrangement is stress resistant
  • Collagen fibers of close Lamellae runs in opposite directions; Resist twisting & bending forces

Central Canal : Endosteum-lined hole in center of Osteon; Blood vessels & nerves supply bone

  • Osteocytes in Lacunae: Small cavities between Lamellae, filled with ECF
  • Lacunae is connected by [Canalculi]-> Canals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Overall Compact Bone Structure

A

-Osteons, NOT perminant
-Osteoclasts break down & Osteoblasts rebuild bone matrix, which depends on the bones need or body’s need;
(Leaves Behind) :
Interstitial Lamellae- Fills space between circular osteons, representing remnant of old osteons
Circumferential Lamellae- Outer & Inner layers of Lamellae, Inside Periosteum; Adds strength & is at the boundary with Spongy Bone
Perforating Canals- Comes from blood vessels in Periosteum, traveling perpendicular;* When it travels, it goes into central canals of neighboring Osteons and connecting them together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Structure of Spongy Bone

A
  • Usually not weight bearing like Compact Bone; Less Densely packed
  • Network of struts reinforcing compact bone; Resisting force from different directions
  • Provides protective structure for Bone Marrow tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Structure of Spongy Bone

[Continued]..

A

Trabeculae- struts or ribs of bone; Covered with Endosteum ;

  • Usually not arranged into Osteons
  • Composed of Concentric Lamellae with Osteocytes in Lacunae; Communicate through Canalculi
  • No central or perforating canals supplying blood to Trabeculae; Obtain blood from vessels in bone marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Structure of Spongy Bone

[Continued]..

A

Osteopetrosis- Marble Bone Disease; Defective Osteoclasts
(Do) (Not) properly degrade bone, causing bone mass to increase and become weak & brittle
-Main Forms:
1. Infantile: Inherited and more severe; Openings of skull & marrow cavities fail to enlarge with growth which traps nerves that cause blindness and deafness. Treated with drugs to stimulate Osteoclasts & Red Marrow
2. Adult: Inherited; Develops during adolescence or later
Symptoms- Bone pain, Recurrent fractures, Nerve trapping, & Joint pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Ossification [Osteogenesis]

A
  • Begins in Embryonic period and is a process is Bone Formation; Continues through childhood and most bones are complete by 7
  • First bone formed is Immature Primary bone; Irregular arranged collagen bundles, Ostocytes, & Sparse Inorganic Matrix
  • Primary Bone is broken down (usually) by Osteoclasts and replaced with Mature, Secondary, or Lamellar Bone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

2 Ossification Mechanisms

A
  1. Intramembraneous- Membrane of Embryonic Connective Tissue
  2. Endochondral- Hyaline Cartilage
30
Q

Intramembraneous Ossification

A
  • Forms Flat Bones during fetal development (Skull & Clavicles)
  • Primary Bone: within Mesenchymal Membrane that is composed of Embryonic Connective Tissue; Populated by Mesenchymal Cells
  • Flat Bone: two outer layers of Compact Bone with Inner layer of Spongy Bone
  • Middle layer of Spongy Bone: ossifies before Outer Compact Bone and begins in Primary Ossification Center
  • Early Spongy Bone: formed as Osteoblasts continue to lay new bone down from [Trabeculae]
31
Q

Intramembraneous Ossification

[Continued]…

A

-Smaller Trabeculae merges from larger structures
-Some Mesenchymal Cells disperse and form Periosteum; Some Vascular Tissue in Spongy Bone turns into Bone Marrow
-Spongy Bone is Deep to Periosteum, becoming heavily Calcified; Structure is rearranged to form Immature Compact Bone
-Larger Bones, more than one Primary Ossification Center; Leads pieces of bone that must fuse to one another
Example: [Fontanels]-> Incompletion of Ossification; Skulls of newborn babies

32
Q

Events of Intramembraneous Ossification

A

-Mesenchymal Cells disperse into Osteogenic Cells, then into Osteoblasts at Primary Ossification center

-Osteoblasts secrete Organic Matrix, Calcium Salts, & other Inorganic Matrix components are deposited in Trabeculae [Calcification]->
+Hardens bone (Primary)
+Osteoblasts trapped in Lacunae become Osteocytes

33
Q

Endochondral Ossification

A
  • Bone development, all bones, (EXCEPT) Clavicles
  • Begins in fetal stage for (MOST) bones; Some bones (Wrist & Ankle) Ossify later
  • Many bones complete by 7
34
Q

Endochondral Ossification for Developing Bone

A
  • Hyaline Cartilage Model: Chondrocytes, Collagen & ECM surrounded by Connective Tissue Membrane [Perichondrium] & Immature Cartilage Cells [Chondroblasts]
  • Begins at Primary Ossification Center; Primary bone is (First) Synthesized and then replaced with Secondary Bone
  • Long Bones contain Secondary Ossification Centers
35
Q

Model Forms, Epichondral Ossification forms in Steps:

A
  • Chondroblasts in Vessel-filled Perichondrium disperse (First) into Osteogenic Cells, then into Osteoblasts forming Periosteum
  • Bone begins where Osteoblasts have built Bone Collar on External surface of Bone
  • At the same time, Internal Cartilage begins to Calcify and Chondrocytes die as blood supply connection is severed; Leaving Calcified Cartilage & Tiny Cavities
36
Q

Endochondral Ossification Steps

A
  • Osteoclasts etch opening in Bone Collar for blood vessels & bone cell entry into Primary Ossification Center
  • Osteoblasts replace Calcified Cartilage with early Spongy Bone; Others Enlarge Bone Collar
  • Cavities enlarge & combine; Medullary cavity develops
  • Secondary Ossification Centers develop in Epiphyses
  • Remaining Ossified Cartilage is replaced by Bone
  • Medullary cavity is Enlarged by Osteoclasts; Fills with Bone Marrow
  • Epiphyses is finished Ossifying
37
Q

Endochondral Ossification Steps:

[Continued]…

A
  • Cartilage (ONLY REMAINS) in Epiphyseal plates & on Articular surfaces where the bone interacts with joints, [Articular Cartilage]
  • Articular Cartilage persists into Adulthood; Epiphyseal plates are replaced with Bone (over time) , once growth in length creases
38
Q

Osteoporosis

A

*Most common Bone Disease; Bones become brittle & weak due to Inadequate Inorganic Matrix which increases risk of Fractures

  • Causes: Diets, Female gender, Age, Lack of exercise, Genetics
  • Diagnosis: Bone Density Measurement
  • Prevention: Balanced diet, Weight bearing exercise, & Estrogen replacement
  • Treatment: Drug that inhibits Osteoclasts or stimulate Osteoblasts
39
Q

Growth In Length

A
  • Long Bones lengthen by [Longitudinal Growth]; Involves division of Chondrocytes in Epiphyseal Plate
  • Bone takes place at Epiphyses on the side closest to Diaphyses
40
Q

Epiphyseal Plate

A
  • Composed of Hyaline Cartilage that (DID NOT) Ossify;

- 5 zones of Cells: Reserve Cartilage,Proliferation, Hypertrophy & Maturation, Calcification, & Ossification

41
Q

Zone of Reserve Cartilage

A
  • Closest to Epiphyses;

- Cells that are (NOT) directly involved in bone growth, but (CAN) be recruited for cell division

42
Q

Zone of Proliferation

A

-Actively dividing Chondrocytes in Lacunae

43
Q

Zone of Hypertrophy & Maturation

A
  • Next region closer to Diaphysis;

- Mature Chondrocytes

44
Q

Zone of Calcification

A

-Dead Chondrocytes, some Calcified

45
Q

Zone of Ossification

A
  • Last Region;

- Calcified Chondrocytes & Osteoblasts

46
Q

Zones of Epiphyseal Plates

A
  • Actively involved in Longitudinal Growth (EXCEPT) the Zone of Reserve Cartilage;
  • Chondrocytes divide in the Zone of Proliferation, forcing cells ahead into the next zones (toward Diaphyses)
  • Chondrocytes that reach the Zone of Hypertrophy & Maturation enlarge and stops dividing
47
Q

Longitudinal Growth Process

A
  • Chondrocytes that reach the Zone of Calcification die, due to being far from blood supply while the Matrix Calcifies;
  • Calcified Cartilage is replaced with bone from the Zone of Ossification
  • Osteoblasts invade Calcified Cartilage and lay bone on top
  • (Eventually) Calcified Cartilage & Primary Bone are resorbed by Osteoclasts and completely replaced with Mature Bone
48
Q

Longitudinal Growth Process

[Continued]…

A
  • Continues ONLY if Mitosis still continues in the Zone of Proliferation*
  • Mitotically Plate (slows) around the age of 12-15 while Ossification continues; Epiphyseal Plate shrinks as the Zone is overtaken by Calcification & Ossification Zone
  • Between the age of 18-21, the Zone of Proliferation is completely Ossified; Longitudinal Growth stops and Epiphyseal Plate is closed
  • Epiphyseal line is Calcified remnant of Epiphyseal Plate
49
Q

Bone Growth in Width

A
  • Appositional Growth*
  • Osteoblasts, In between Periosteum & Bone surface, lays new bone
  • Appositional Growth (DOES NOT) result in Immediate formation of Osteons; Instead, new Circumferential Lamellae are formed
50
Q

Appositional Growth

A
  • As new Lamellae are added, older deeper Circumferential Lamellae are removed or reconstructed into Osteons;
  • Bone Growth in Width can continue after bone growth in length ceases, which depends on factors like hormones, diet, and forces to which bone is subjected
51
Q

Achondroplasia

A
  • Common cause of Dwarfism; Gene defect is Inherited from a parent or new mutation
  • Defective Gene produces abnormal growth receptor on Cartilage, which interferes with Hyaline Cartilage Model used in Endochondral Ossification; Also in Articular & Epiphyseal Cartilage
  • Bones form & grow abnormally; Resulting in short limbs, Disproportionally long trunk, and Facial abnormalities
  • Long term includes Joint disorders, Respiratory difficulties, & Spinal Cord compression; Can be managed with medication
52
Q

Factors that play a role in How Much Cell Division occurs & How long the process remains Active in Epiphyseal Plate:

A
  • Main factor is Hormones; Hormones are secreted by Cells of Endocrine Glands
  • Growth Hormone: secreted by Anterior Pituitary Gland; Enhances Protein Synthesis & Cell Division in (ALL) Tissues, Including Bone
53
Q

Longitudinal & Appositional Growth Effect

A
  • Increases cell division rate of Chondrocytes
  • Increases Osteogenic cell activity, Including Zone of Ossification
  • Stimulates Osteoblasts in Periosteum
54
Q

Male Sex Hormone [Testosterone] Effect

A
  • Increases Appositional Growth; Bones in Males become thicker with more Calcium Salt Deposition
  • Increases rate of Mitosis in Epiphyseal Plate, which leads to “Growth Spurts” in teenage years
  • Accelerates closure of Epiphyseal Plate
55
Q

Female Sex Hormone [Estrogen] Effect

A
  • Increases Longitudinal Bone’s Growth rate; Inhibits Osteoclast activity
  • When Estrogen levels spike, “Growth Spurts” occur
  • Accelerates closure of Epiphyseal Plate at a (MUCH FASTER) rate than Testosterone; Leads to average height differences between genders
56
Q

Excess Growth Hormone Produces Two Conditions

A
  • Depends on when it develops *
    1. Childhood-Gigantism: Epiphyseal Plates (HAVE NOT) Closed; Therefore, Individuals grow tall due to excessive Longitudinal & Appositional Bone Growth
  1. Adulthood-Acromegly: Epiphyseal Plates (ARE) Closed; No height increase, but enlargement of Bone, Cartilage, & Soft Tissue
    - Skull, Bones of Face, Hands, Feet, & Tongue [Affected]
    - [Can] cause Heart & Kidney Malfunction
57
Q

Bone Remodeling

A

-Continuous process of Bone Formation & Loss after Length Growth is complete; New Bone is formed, by [Bone Deposition]-> old bone is removed by [Bone Resorption]

58
Q

Reasons for Bone Remodeling & Repair

A
  • Maintenance of Calcium Ion Homeostasis
  • Replacement of Primary Bone with Secondary Bone
  • Bone Repair
  • Replacement of old brittle bone with newer bone
  • Adaptation to tension & stress
59
Q

Bone Remodeling

[Childhood & Healthy Bone]

A
  • In Healthy Bone: the process of formation & loss occurs simultaneously; Bone broken down by Osteoclasts matches the Bone formation by Osteoblasts
  • In Childhood: deposition processes much faster than resorption; Once Epiphyseal Plates close & Longitudinal Growth is complete, deposition & resorption becomes equivalent
60
Q

Bone Deposition

A
  • Carried out by Osteoblasts
  • Found In Periosteum & Endosteum; Making Organic Matrix & Facilitate the formation of Inorganic Matrix
  • Secretes Proteoglycans & Glycoproteins that bind to Calcium Ions
  • Secretes Vesicles that contain Calcium Ions, ATP, & Enzymes; Binds to Collagen Fibers, in which the Calcium Ions Crystalize rupturing vesicle and begins the Calcification process
61
Q

Bone Resorption

A
  • Osteoclasts secrete Hydrogen Ions on the Bone’s ECM
  • Hydroxyapatite crystals in Inorganic Matrix are pH sensitive; Breaks down in acidic environment created by Osteoclasts
  • Calcium ions and other liberated minerals can be used/refused elsewhere in the body
62
Q

Osteoclasts Secreting Enzymes

A
  • Degrade Organic Matrix, Includes Proteoglycans, Glycosaminoglycans, & Glycoproteins
  • Breakdown products of Matrix are taken into Osteoclasts for reuse
63
Q

Bone Resorption in Response to Tension & Stress

A
  • Compression: Squeezing or Pressing together; Occurs when bones are pressed between body’s weight and ground, which stimulates bone deposition
  • Tension: Stretching force; Bone deposition occurs in regions of bone exposed to tension
  • Pressure: Downward continuous force; Bone resorption is stimulated in regions of bone exposed to continuous pressure
64
Q

Additional Factors Influencing Bone Remodeling

A
  • Hormones: Testosterone promotes bone deposition; Estrogen inhibits Osteoclast activity
  • Age: Growth Hormone & sex hormones decline as individuals age; Decreases protein synthesis in bone
  • Calcium Ion Intake: (diet) must be adequate to support bone deposition
  • Vitamin D Intake: (diet) must be adequate to promote Calcium Ion absorption from the Gut and prevent Calcium Ion loss in Urine
  • Vitamin C Intake: (diet) adequate for synthesis of Collagen
  • Vitamin K Intake: (diet) adequate for synthesis of Calcium Ion binding Glycoproteins secreted by Osteoblasts
  • Protein Intake: (diet) adequate for Osteoblasts to synthesize Collagen Fibers in Organic Matrix
65
Q

Calcium Ion Homeostasis

A
  • Bones store (MOST) of Calcium Ions in body
  • Stored Calcium Ions are not only used for bone deposition & remodeling, but is used throughout the body for several critical processes [Muscle Contraction]
  • Negative Feedback loop maintains Calcium Ion in Homeostasis in blood
  • Calcium Ion levels in blood are closely monitored; Both high & low levels can lead to major homeostatic disruptions [Death]
66
Q

Negative Feedback Loop

A

-Stimulus & Receptor: When Calcium Ion levels drop in blood, it is detected by Parathyroid Cells
-Control Center & Effector: Parathyroid cells act as control center; Secrete Parathyroid Hormone, PTH
-Effect/Response: PTH stimulates effects that increase blood calcium ion levels;
Increases Osteoclast activity; breaks down Inorganic Matrix of bone releasing calcium ions from hydroxyapatite crystals
-Increases absorption of Calcium from Gut
-Inhibits Calcium loss in Urine

67
Q

Homeostasis & Negative Feedback

A

-As Calcium Ion levels return to normal in the blood, change is detected by Parathyroid Cells; Secretion of PTH is reduced, closing the feedback loop

68
Q

Calcium Ion Homeostasis

A
  • Increased blood calcium levels trigger different negative feedback loop; First response is drop in PTH secretion by Parathyroid Gland
  • Calcitonin is secreted by Thyroid Gland; Opposite effects as PTH; Leads to bone deposition, pulling Calcium Ions out to manufacture Inorganic Bone Matrix. Most active during Bone Growth & less in adulthood
  • Vitamin D, important for Calcium Ion homeostasis due to absorption of Ions
69
Q

Bone Repair

A
  • Most dramatic Bone injury is [Fracture]-> broken bone

- 2 Types: Simple & Compound

70
Q

Simple Fracture

A

-Skin & Tissue around fracture remains Intact

71
Q

Compound Fracture

A

-Skin & Tissue around the fracture is damaged

72
Q

Healing Process of Fracture

A
  1. Hematoma-(blood clot) that fills in the gap between Bone Fragments:
    - Mass of blood cells & proteins forms due to ruptured blood vessels
    - Bone Cells in surrounding areas die
  2. Fibroblasts & Chondroblasts- (Periosteum) Infiltrate Hematoma and Forms Soft Callus-> mixture of Hyaline Cartilage & Collagenous Connective Tissue; Bridges gap between Fragments
    - Fibroblasts form Dense Irregular Collagenous Connective Tissue
    - Osteogenic Cells become Chondroblasts; Secretes Hyaline Cartilage
  3. Osteoblasts build Bone Callus- (Hard Callus) Collar of Primary Bone made by Osteoblasts in Periosteum; Forms a bridge between Fragments
  4. Bone Callus is Remodeled & Primary Bone is replaced with Secondary Bone- bone regains previous structure & strength after several months

A & P I (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions