Exam 1 Flashcards
The Skeleton is composed ofliving organs that function to……..
- support and protect
- work with skeletal muscles to producemovement
- produce formed elements of blood(hematopoiesis)
- store nutrients, esp. mineral salts
Bone Classification by Shape
What tissue makes up articular cartilage?
connective tissue
Describe the functions of the periosteum.
The periosteum is a connective tissue that supports bone health and development. The thin tissue has two layers that function in different ways. The outer layer, known as the fibrous periosteum, allows for attachment of muscle tissue to the bone and provides pathways for blood and lymphatic tissues.
Bone Tissue is composed of different cell types in two different arrangements
What is osteoid?
the unmineralized organic component of bone.
Differentiate between the
organic and inorganic
components of the bony matrix (structure and function)
Bone is composed of both organic and inorganic components. Inorganic components include calcium hydroxyapatite and osteocalcium phosphate. Organic components include collagen, proteoglycans, matrix proteins, cytokines and growth factors
The cells of bone tissue come from different types of mesoderm
Osteon
= lamellae (rings) of mineralized matrix
– calcium & phosphate—give it its hardness (________________)
– interwoven collagen fibers (and other proteins) provide strengthand flexibility (______________)
Osteocytes
Osteocytes in spaces (lacunae) in between lamellae
Canaliculi
Canaliculi (tiny canals) connect cell to cell
– Central canal contains blood vessels, nerves & a lymphatic vessel
__________ and _________ is found in most bones
Compact and Spongy Bone Tissue is found in most bones
Which region of the skeleton is the bone at left from?
skull
What type of bone marrow is found within the spaces of spongy bone?
Which cells lay down fresh bone matrix?
Which cells “recycle” bone matrix?
Where are cells located in bone tissue?
osteogenesis
Animal growth and development is characterized by cell movement, e.g. osteogenesis
• Osteoblasts secrete proteins, including more collagen fibers for the matrix
– Gives bone tissue its strength and flexibility
– Osteoblasts become osteocytes as they age
Osteogenesis follows this basic pattern of development:
Osteogenesis follows this basic pattern of development:
- mesoderm layer of cells is created in the embryo
- some mesoderm cells migrate (becoming mesenchyme)
- some mesenchyme cells specialize into osteoblasts
- osteoblasts secrete matrix (becoming osteocytes)
- e.g. pouring reinforced concrete – casting the negative space
How is bone tissue formed in
these 2 arrangements?
(Compact & Spongy)
OSTEOGENESIS
Common to both types of bone formation:
a) A connective tissue pattern (model) is formed, which is subsequently ossified by osteoblasts.
b) Osteoblasts develop from mesenchyme and produce a matrix,becoming osteocytes trapped in lacunae of the matrix:
1) organic = “osteoid”
2) inorganic = “calcium hydroxyapatitie”
c) A thin layer of compact bone surrounds areas of spongy bone.
Osteogenesis - 10 week fetus
Connective tissue that remains on the surface of the developing bone becomes the _________.
Connective tissue that remains on the surface of the developing bone becomes the periosteum
Ossification of membranes begins at the center of each model….
Osteoblasts on inside of periosteal membranes form 2 thin layers of
compact bone over the spongy bone.
Osteogenesis - 16 week fetus
Endochondral Ossification
How is it possible that blood vessels can invade the cartilage pattern if cartilage is avascular?
Describe the difference between perichondrium and periosteum.
Differentiate between the primary ossification center
and secondary ossification centers.
From which embryonic germ layer are the tissues of bone derived?
Which bone tissue organization do you think is stronger (and why): spongy bone or compact bone?
PROCESS OF OSSIFICATION
Which joint is shown in the x-ray at right?
Indicate the direction(s) of ossification in the x-ray.
What factors influence the normal growth and maintenance of bone?
Bone Growth in Width:
Does this kind of appositional growth occur in flat bones? Explain…
Other factors necessary for normal ossification:
Calcium
1000mg adult RDA; 1200mg for adults over 50; 1300mg for pregnant andnursing women up to age 18, 1000mg for pregnant and nursing women19-50 years
Other factors necessary for normal ossification:
- Calcium: 1000mg adult RDA; 1200mg for adults over 50; 1300mg for pregnant and nursing women up to age 18, 1000mg for pregnant and nursing women 19-50 years
- Vitamin C: to produce collagen in the manufacture of osteoid
- Vitamin D: for the absorption of calcium in the small intestine (phosphate follows by electrostatic attraction)
- Vitamin A: for bone reabsorption and normal ossification
- Collagen fibers: stimulate the mineralization of bony matrix
- Pyrophosphotase: may prevent mineralization of collagen fibers found elsewhere in the body
- Osteoblastic hormones: thyrocalcitonin, somatotropin (GH), testosterone, andestrogen
- Osteoclastic hormones: parathormone (PTH), thyroxine, corticosteroids
- Load-bearing exercise: mechanism . . . ?
1 cup of milk (1%, 2% or whole) has about 300 mg
Calcium: 1 cup low fat plain yogurt has about 415 mg Calcium
General Functions of the Skin
Regulation of body temperature
Protection as a physical barrier
Sensory receptors•Excretion and absorption
–small amounts salt, CO2, ammonia and urea are excreted
Involved in the synthesis of vitamin D
Regulation of body temperature
–Describe the homeostatic mechanisms
Protection as a physical barrier
–Most importantly, what chemical does the skin keep in?
–What materials do not pass through intact skin?
–What materials may pass through intact skin? Why?
Overview of Epidermis
- Stratified squamousepithelium
- Contains no bloodvessels
- several strata (layers) ofcells
What is the origin of theupper layers ofepidermal cells?
Why is the structure andfunction of epidermalcells different in thedifferent strata?
Dermis
Connective tissue layer composed of collagen & elastic
fibers, fibroblasts, macrophages & adipocytes
• Contains hair follicles, glands, nerves & blood vessels• Major regions of dermis
–papillary region–reticular region
Describe the location of the following injections:
subcutaneous (SQ),
hypo-dermic, i
ntradermal (ID),
andintramuscular (IM).
Differentiate between calluses andpressure (decubitus) ulcers.
How are sweatglands and ceruminous glands similar?
What is sebum?
What is the relationship between hair, nails and the epidermis?
Photodamage
- Ultraviolet light (UVA andUVB) both damage the skin
- Acute overexposure causessunburn
- DNA damage in epidermalcells can lead to skin cancer
- UVA produces oxygen freeradicals that damage collagenand elastic fibers and lead towrinkling of the skin
1 in _ people will develop skin cancer in their lifetime
1 in 5 people will develop skin cancer in their lifetime
In the past 30 years, more people have died from ____ cancer than all other cancers combined
In the past 30 years, more people have died from skin cancer than all other cancers combined
Common forms of skin cancer:
Common forms of skin cancer:
- basal cell carcinoma (rarely metastasize)
- squamous cell carcinoma (may metastasize)• often develops from Actinic Keratosis
- malignant melanomas (metastasize rapidly)
What kind of molecules may make up these intercellular junctions?
Differentiate between primary tissues and
embryonic germ
layers.
Tight Junctions
This type of intercellularjunction is common intransport epithelia.
Why do you think tight junctions arelocated nearer the luminal cellborder rather than the basolateralborder
Describe the structure and functionof the apical cell border for thesecells that line the intestine.
• Where are transport epithelia
Gap Junctions
What kinds of materials maypass between cells throughgap junctions?
In which tissues are gapjunctions common?
Desmosomes
Give at least two examples oftissues containing desmosomes.
- Where else would you expect tofind keratin, and for whatpurpose?
- What analogy would you use todescribe the structure of adesmosome?
- What function does this structuralfeature provide for the tissue?
Epithelial Tissue – General Features
Epithelial Tissue – General Features
Epithelial Tissue – General Features
• Cover surfaces, line cavities and form glands
– Name one multicellular gland formed by epithelial tissue.– Differentiate between endocrine, exocrine and heterocrine glands.
• Attached to underlying connective tissue by a basementmembrane
• Avascular—without blood vessels– nutrients diffuse in from blood vessels in underlying
connective tissue
– What does this mean for especially thick epithelia?
• Good nerve supply• Rapid cell division; responsive to environmental stresses• Named according to the shape and arrangement of cells
– List the general functions of epithelial tissues
Connective Tissues
Cells rarely touch due to usually large amount ofintercellular material (extracellular matrix)
• Matrix (fibers & ground substance) secreted by cells
– Consistency varies: liquid, gel, or solid
• Function is to support, connect, protect and insulate• Good nerve & blood supply except cartilage & tendons
Collagen
Elastin
• Collagen (25% of protein in your body)
– tough, resistant to pull, yet pliable
- Elastin (lungs, blood vessels, ear cartilage)
- Reticular (spleen and lymph nodes)
– thin, branched fibers that form frameworkwithin organs
– formed from protein collagen
• smaller diameter fibers formed from proteinelastin surrounded by glycoprotein (fibrillin)• can stretch up to 150% of relaxed length andreturn to original shape
Embryonic Connective Tissue:
Mesenchyme
Irregularly shaped cells
• In semi-fluid ground substance with reticularfibers
• Gives rise to all other types of connective tissue
Types of membranes
– mucous membrane
– serous membrane
– synovial membrane
– cutaneous membrane (skin)
Serous Membranes
Synovial Membranes
The Cutaneous Membrane
