EXAM 3 Flashcards
Functions of the Skeleton
Support—limb bones and vertebrae support body; jaw bones support teeth; some bones support viscera
Protection—of brain, spinal cord, heart, lungs, and more
Movement—limb movements, breathing, and other movements depend on bone
Electrolyte balance—calcium and phosphate levels
Acid–base balance—buffers blood against large pH changes by altering phosphate and carbonate salt levels
Blood formation—red bone marrow is the chief producer of blood cells (rbc, wbc, platelets)
Sound Amplification – small bones of the middle ear (ossicles – malleus, incus, stapes)
Bone (osseous tissue)
connective tissue with the matrix hardened by calcium phosphate and other minerals
General Features of Bones
Flat Bone-Thin, curved plates protect soft organs Wider than long
Long Bone- Longer Than Wide
Short Bone- equal length
Irregular Bone- Shapes that do not fit in a categories .
The four principal types of cells in bone tissue include:
- Osteogenic (osteoprogenitor) cells
- osteoblasts
- osteocytes
- osteoclasts
- Spongy Bone
o lighter in density than compact bone
o has an irregular, honeycomb-like appearance
o present during bone development and can be found in the marrow cavities of long bones
o form networks of trabeculae which allow for nutrient diffusion without the use of blood vessels.
- Cartilage
o Hyaline cartilage acts as the articular cartilage in our joints, coverings at the ends of long bones, and support for the tip of the nose and much of the respiratory system.
o Elastic cartilage is present in the external ear and epiglottis, and is similar to hyaline cartilage, but with more elastic fibers in the matrix.
o Fibrocartilage is located in body regions that require strong support and the ability to withstand pressure (specifically in the knee, pubic synthesis, and spine). This type of cartilage obtains its more rigid characteristics from rows of chondrocytes alternating with thick collagen fibers in the matrix.
- Dense Regular Connective Tissue
o Tendons – attach muscle to bone allowing for the muscle to pull on the bone and create movement
o Ligaments – attach bone to bone and prevent excessive movement at a join
o Tendons
attach muscle to bone allowing for the muscle to pull on the bone and create movement
o Ligaments
attach bone to bone and prevent excessive movement at a joint
- Sutural bone
as the bones of the skull begin to grow, they join up together into a joint known as a suture. As these sutures begin to close, there can be an additional bone(s) that can grow in the suture
o Epiphysis
(proximal and distal) this is the ends of the long bone. They are typically enlarged to accommodate the attachment of ligaments and tendons. The end closest to the attachment of the limb is referred to as the proximal end and the one furthest away is known as the distal end. This portion of the bone is mainly made up of spongy bone.
o Articular Cartilage
is found on the epiphysis. It is typically made up of hyaline cartilage and forms the joints of the bone.
o Metaphysis
Sits between the epiphysis and diaphysis. This area contains the epiphyseal GROWTH PLATE, where long bones grow longitudinally. This happens when the hyaline cartilage of the growth plate converts into bone. When bone growth longitudinally ceases, the
growth plates will be replaced with the epiphyseal line.
o Medullary Cavity
this is the empty cavity within the diaphysis of a long bone. In early childhood, it is filled with red bone marrow. The red bone marrow is replaced with yellow bone marrow in adulthood.
o Endosteum
a thin layer of connective tissue lining the medullary cavity.
o Periosteum
dense fibrous connective tissue lining the outside of the diaphysis. The inner layer of the periosteum is the osteogenic layer lined with osteoblasts and allows for bone remodeling and growth. The periosteum is also highly innervated and thus causes pain if damaged.
- Structure of Skin
o Epidermis
o Dermis
o Subcutaneous layer (hypodermis
Accessory Structures
o Sweat glands
o Oil (sebaceous) glands
o Hair
o Nails
Functions of Skin
- Protection- against dehydration and infection (includes acid mantle, keratin, antimicrobial peptides)
- Synthesis of Vitamin D- contributes to bones
- Sensation – skin is largest sense organ: tactile, thermal, pain
- Thermoregulation -regulating body temp in cold and hot environment, sweat and evaporation
- Nonverbal communication- expressive faces, general appearance of skin/hair
Epidermis- comprised of 5 cell types
- Stratified squamous epithelium
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
Papillary Layer
most superficial layer of dermis
Made of areolar tissue
Rich in blood supply
Reticular Layer
Dense irregular tissue, collagen & elastic fibers
Hair follicles, hair roots, nerve endings, cutaneous glands
Produces stretch marks (striae) due to collagen fibers tearing
o Cutaneous Membrane
dermis + epidermis
- Subcutaneous Layer (Hypodermis)
o Consists of loose connective tissue (adipose, areolar)
o Well-vascularized
o Connects skin to fascia beneath it
o Provides insulation, stores fat
o Keratinocytes
90% of epidermal cells
Produce keratin- toughens and protects skin
Produces granules for water- proofing, prevents entry of pathoge
Melanocytes
Produce melanin pigment
Stratum basale
Long slender projections connect with keratinocytes, melanin shuttled there
Form protective shield over nucleus to protect DNA from UV damage once inside keratinocyte.
o Langerhans Cells
AKA dendritic cells or intraepidermal macrophages
Migrate from bone marrow
Stratum spinosum and granulosum
Mount immune response to microbes, easily damaged by UV light
o Merkel (tactile) Cells
Receptors for touch and are connected to a dermal nerve fiber.
Stratum basale
Attached w/ nerve to a “tactile disc”
o Papillary layer
supplies nutrients to epidermis, helps regulate temperature
Reticular layer
full of fibers for strength, elasticity. Also has hair follicles and glands.
Collagen/Elastic Fibers
tensile strength, resist pulling and stretching
o Fibers produces by fibroblast cells, and form matrix of dermis
o Adipocytes – produce fat, connects with hypodermis
- Function and Cells of the Hypodermis
o Called subcutaneous layer or hypodermis
o Contains fat (more than dermis) and areolar tissue.
o Protects and pads underlying tissue, stores energy, provides insulation
o Highly vascularized and absorbs injected drugs quickly
Thermoregulation
Sweat – released from sweat glands in dermis
Insulation – by adipose tissue in hypodermis
Vasodilation/vasocontriction – of blood vessels in dermis
o Hair shaft
– part of hair above skin
o Hair root
portion below the skin
o Hair bulb
ending of the hair root
- Medulla
– loosely arranged cells
- Cortex
more tightly packed keratinized cells, makes up bulk of hair
- Cuticle
many layers of scaly cells, overlapping like house shingles.
Scalp
layer of fat to protect cranium
* Hair protects from heat loss on head, brain supply of blood warm, UB light
Nostrils and Ears, Eyebrows/Eyelashes
protection from foreign particles
* Keeps sweat /debris from eyes, facial expression
Sensory detection, identify species, age, sex, individual differences
o Hair Growth
- Anagen (growth) – 6-8 years, stem cells multiply, hair lengthens. After 40’s, hair spends more time in other stages,
- Catagen(Regression) – Mitosis stops, follicle shrinks, easily pulled out by brushing, lasts 2-3 weeks
- Telogen(rest) – lasts 1-3 months, follicle rests
o Eccrine sweat glands
All over, abundant in palms, soles, forehead
Cool body (function), appear like twisted coil
o Apocrine sweat glands
Respond to stress and sexual stimulation
Found in axilla, groin, anal region
Thicker milky sweat compared to eccrine
More odiferous
o Sebaceous glands
Produce oily sebum
Open up to a hair follicle, prevents skin from being dry and brittle
Ceruminous glands
Apocrine glands in the ear
Produce cerumen (earwax)
Keeps ear canal soft, waterproof, captures bacteria
o Mammary glands
In breasts of females, produce milk in lactating or pregnant women
Modified apocrine glands
o First degree
Include only the epidermis
Redness, slight edema, and pain
Usually healed within days with little scarring
o Second Degree
Involve the epidermis and part of the dermis
Red, tan or white in color. Involves blistering and pain, may scar
2-weeks to month to heal
o Third degree
Full-thickness burns because all of epidermis, all of dermis, and deeper tissues are involved.
Skin only regenerates from the edges of the wound, scarring occurs
Often requires skin grafts
o Fluid Replacement and Infection control
Amount of circulating blood decreases as a result of fluid loss
Burn patient can lose 75% of circulating plasma in a few hours, resulting in circulatory shock or cardiac arrest (main cause of death in burn patients).
Infection control – keeping burn infection -free
Debridement – removing eschar (burned or dead tissue
Basal cell carcinoma
- Most common type
- Appears as shiny, small bump that often enlarges with a “pearly” edge
- Seldom metastasizes
- Originates from the cells in the stratum basale
Squamous cell carcinoma
- Originates in keratinocytes of stratum spinosum
- Can lead to metastasis in lymph nodes if untreated
- Raised, red, scaly appearance with ulcer in the middle
Melanoma
- Originates in melanocytes
- Especially aggressive and can quickly metastasize
- Appears as “spilled ink”
- Uses ABCD rule: A for asymmetry (irregular shape), B for border irregularity (border is wavy not smooth), C for color (often brown or black), D for diameter (greater than 6 mm)
Epiphyseal Plate
o Long bones will continue to grow until early adulthood that gives an adult their height. This growth happens at the growth plates of long bones and resembles endochondral bone growth.
o Consists of hyaline cartilage
o Found in metaphysis of bone
Zone of Reserve Cartilage
this is the area of cartilage furthest from the diaphysis. It contains resting chondrocytes that do not show any signs of transformation.
Zone of Proliferating Cartilage
– as we begin to move closer to the diaphysis the chondrocytes in this zone will begin to multiply and begin to arrange into longitudinal columns of flattened lacunae.
Zone of Hypertrophy
continuing to move closer to the diaphysis the chondrocytes in this zone cease to multiply. The cells begin to enlarge (hypertrophy). The walls of the matrix between the lacunae and the matrix becomes very thin.
Zone of Calcifying Cartilage
– the next layer closest to the diaphysis is the zone of calcifying cartilage. In this zone minerals are being deposited into the matrix. These temporary mineral depositions into bone are occurring between the columns of lacunae.
Zone of Bone Deposition
– in this zone of cartilage closest to the diaphysis the chondrocytes die. The matrix between the columns is converted and blood immediately invades the area. The osteoclasts are removing the temporary bone that was deposited in the zone of calcification. Osteoblasts begin to create the lamella depositing bone. This deposition begins to add bone to the diaphysis extending it in the longitudinal growth. This growth is known as interstitial or lengthwise bone growth.
- Remodeling – process of appositional growth (width or circumference)
As the periosteum stretches due to stress, it triggers the periosteal cells to differentiate into osteoblast cells. The osteoblast cells then begin to secrete collagen fibers and begin to lay down bone extracellular matrix. This allows the osteocytes to begin to be surrounded by the bone matrix creating lacunae and maturing the osteoblasts into osteocytes. As the matrix grows, it begins to form ridges around the periosteal arteries.
The folds eventually fuse together with a tunnel in the center for the periosteal artery. The former periosteum that is now lining the inner canal is now endosteum.
The osteoblasts continue to deposit bone matrix now forming new concentric lamellae. The combination of the new central canal, the new lacunae, and new concentric lamella join to form a new osteon.
As the osteon forms, new osteoblasts continue to deposit bone creating more concentric lamella and continuing to increase the thickness of the bone.
o If the stress is reduced on the bone due to inactivity, bone will reduce the thickness (bone reabsorption):
Activating osteoclasts which will release a protein-digesting lysosomal enzyme and several acids. These chemicals will breakdown bone matrix releasing calcium and other minerals into the bloodstream. This action will reduce the thickness of the bone.
3 steps to bone repair:
Reactive phase, blood forms a hematoma (collection of blood that is outside of blood vessels) at the injury site, allowing for immune cells to clean up the damaged tissue from the area.
Reparative phase begins where a fibrocartilaginous (soft) callus starts to form. This callus will then become calcified and form the bony (hard) callus.
Remodeling -smooth out the edges of the injury site, utilizing osteoclasts to degrade the original fragments of broken bones.
o Paranasal Sinuses
Lighten the skull
Moisten or humidify air you breathe in
Filter the air you inhale
Warm the air as it inters your body
Serve as a resonating chamber for sound
Located in the following bones:
Ethmoid sinus
Frontal sinus
Maxillary sinus
Sphenoid sinus
vertebrae
7- cervical
12- thoracic
5 - lumbar
Ribs
True Ribs= # 1-7
False = # 8-12
Floating Ribs = # 11-12
study of joints
- Arthrology
study of movement
- Kinesiology
Classification of Joints
o Synarthrosis- Allow no movement
o Amphiarthrosis- Allow little movement
o Diarthrosis-Freely moveable
- Structural Classification
o Bony Joints/ Synostosis: Ossified joints where no movement is allowed. Eg the joint between the two frontal bones in skull
o Fibrous joints/ Synarthrosis (fig 9.2): articulating surfaces fit closely bound by collagen fibers. Three subtypes of fibrous joints are
Sutures: Immobile joints found only between the bones of skull.
Gomphoses: Ligaments of collagen fibers form joints between areolar process of mandibular or maxilla and root of teeth called periodontal ligaments.
Syndesmoses: Long collagenous fiber joint between two bones, an example is interosseous membrane found between shafts of radius and ulna
Calcitonin:
Produced by Para follicular cells of parathyroid gland
- Osteoporosis
a bone disorder when bone resorption outpaces bone deposition, and as a result the bone density declines and these become brittle and easy to break.
Spongy bone loss is higher as it is mostly prone to the activity of osteoclasts.
Onset of osteoporosis is dependent on several genetic, age and family health history factors.
Osteoarthritis
a degenerative joint disorder resulting from gradual loss of articular cartilage that provides cushion to the articulation bones at synovial joints.
