Final exam condensed Flashcards
Simple epithelium
One layer, found in areas like the alveoli that need thin tissue for diffusion
Stratified epithelium
2+ layers, found in areas like the esophagus that need thick tissue to resist mechanical or chemical stress
Where is the body is epithelial tissue found?
Covers/lines organs and body cavities (outer layer of skin, urogenital, digestive, and respiratory systems). Also glandular epithelium that makes up the glands of the body
Basement membrane
The epithelial tissue is attached to the basement membrane, which is made up of fibers rather than cells. This allows nutrients to diffuse to the epithelial tissue, which is avascular.
Connective tissue characteristics (3)
- Cells
- Ground substance
- Fibers
The ground substance and fibers make up the matrix
Covering epithelium is joined by
Tight junctions and desmosomes
Basement membrane layers (2)
- Basal lamina- secreted by the epithelium itself
- Reticular lamina- contains fibers that belong to connective tissue. Bottom layer of the basement membrane, sits closest to connective tissue
Epithelial tissue is the only tissue type that has apical basal polarity. Why is this important?
One free (apical) surface is necessary, as the epithelium covers the body and lines body cavities
Pseudostratified columnar epithelium
“False” stratified cell nuclei lie at different levels- the nuclei are displaced so it looks like there are multiple layers of cells. Only some cells stretch from the apical surface to the basal surface. “Short” cells give rise to “tall” cells (the cells are different sizes). Shorter cells attach to the basement membrane. Located in respiratory tract, male ducts, and ducts of large glands. Responsible for secretion and absorption.
Under a microscope, you see that many cells of an exocrine gland are in metaphase. Is this a merocrine or a holocrine gland?
Holocrine. Holocrine glands release products as a result of cell rupture. Sebaceous glands are an example
Merocrine glands
Product secreted from the acinus via exocytosis, cell remains unchanged. Example- sweat or salivary glands
Apocrine glands
Similar to holocrine, but do not truly rupture. The cells have a small tear in the membrane so the secretion can leave, and the membrane quickly reassembles. Mammary glands could be an example
Functions of connective tissue (5)
- Binding and supporting
- Protecting
- Insulating
- Storing reserve fuel
- Transporting substances within the body
What types of fibers can be found in connective tissue (3)?
- Collagen- resist pulling forces
- Elastic- high density in areas of the body that are subjected to frequent stretching- skin, lungs
- Reticular- high density in areas of the body where connective tissue attaches to another tissue
What type of connective tissue is capable of acting as a fluid reservoir?
Areolar tissue can act as a fluid reservoir because of its web-like nature.
What type of connective tissue is damaged when you lacerate a tendon?
Dense regular connective tissue
When aging cartilage tends to ossify, its cells die. What survival needs are not being met in those cells?
Oxygen and nutrient needs are not being met. The calcified cartilage matrix is too hard to allow for these substances to reach the cell by diffusion.
What type of membrane consists of epithelial and connective tissue, and lines body cavities open to the exterior?
Mucous membranes fit this criteria. It lines any body cavity that leads out of the body and is a wet/moist membrane. Function- absorption/secretion.
What type of membrane lines the thoracic walls and covers the lungs?
The serous membranes (pleurae) line the body cavity and cover the lungs.
What is the difference between the serous and mucus membranes, and the plasma membrane and basement membrane?
Plasma membranes surround cells and are made of phospholipids. The basement membrane is a layer of extracellular material that lies just outside the basal surface of epithelial cells. Serous and mucous membranes are considered organs because they are composed of multiple types of tissues.
The serous membranes are held together by serous fluid, which is mainly water. What property of water makes them stick together?
Water’s high surface tension due to its hydrogen bonds
What are the 3 main steps of tissue repair?
- Inflammation
- Organization
- Permanent repair via regeneration and fibrosis
Why does a deep injury to the skin result in abundant scar tissue?
More severe injuries damage and destroy more tissue, requiring greater replacement with scar tissue.
One patient has brain damage from a stroke, one had a heart attack, and one has a damaged liver (a gland) due to a car accident. Which one will regain full function of the damaged organ through tissue regeneration?
The liver is a gland derived from epithelial tissue. Epithelial tissue regenerates well, but nervous tissue in the brain and cardiac muscle exhibit virtually no functional regeneration.
Types of covering and lining membranes (3)
These are considered simple organs.
- Cutaneous (skin)- composed of keratinized stratified squamous epithelia
- Mucous
- Serous- line closed body cavities
Types of cartilage (3)
- Hyaline- found in trachea, nose, ends of joints
- Elastic- very flexible
- Fibrocartilage- found in areas of the body that need a lot of support/bear a lot of weight
Types of connective tissue
- Connective tissue proper (areolar, adipose, dense regular)
- Cartilage
- Osseous tissue
- Blood
Marfan Syndrome
A genetic disorder that affects the body’s connective tissue. Results from a mutation in the FBN1 gene, which codes the production of fibrillin. This protein contributes to strength and elasticity. Connective tissue loses strength/elasticity. Connective tissue is located throughout the body, so symptoms are widespread- bones, blood vessels, eyes, respiratory system
Simple gland
Unbranched duct- one straight tube into secretory unit
Functions of the skin (6)
- Protection (chemical, physical, biological)
- Temperature regulation
- Sensation- cutaneous receptors
- Metabolic functions (vitamin D absorption and production)
- Reservoir for blood
- Excretory- sweat eliminates waste
Tactile and lamellar corpuscles
Responsible for touch sensations
Hypodermis functions (4)
- Storage- easy to access energy source for the body
- Protection/shock absorption- prevents physical trauma to internal organs
- Insulation- prevents excessive heat loss
- Anchor- holds skin to underlying skeletal muscle tissue- is still flexible
Cellular portion of epidermis (4)
- Keratinocytes- produce keratin (fibrous protein, very tough). Give the epidermis its dry and tough quality.
- Melanocytes
- Dendritic cells
- Tactile cells (Merkel cells)
Keratinocytes are linked by
Linked by desmosomes (with some tight junctions). Tight junctions are important to prevent releasing water to the environment
Where are melanocytes located?
The stratum basale
Dendritic cells (Langerhans cells)
Move to epidermis from bone marrow. Active macrophages- this activates the immune system
Tactile cells (Merkel cells)
Present in epidermal-dermal junction. Associated with nerve endings- sensory receptor function (2 types of touch)- light touch
and vibration
5 layers of the epidermis
- Stratum corneum- dead keratinocytes
- Stratum lucidum- dead cells, relatively transparent, not found in thin skin
- Stratum granulosum- keratinization begins here, has lamellar granules to make the skin waterproof
- Stratum spinosum- contains pre-keratin- thick bundles of filaments that resist tension. Dendritic cells are most abundant here (immune system).
- Stratum basale- single layer of stem cells attached to dermis
All reproduction in the epidermis comes from this layer- melanocytes and keratinocytes are found here.
Papillary dermis
More superficial layer, made of thin areolar connective tissue. Fibers are thin- defensive cells wander freely here. Has projections called dermal papillae. Can have either pain receptors or tactile corpuscles
Increase the surface area of the dermis so the epidermis can be better attached to the dermis. Also, the amount of nutrients and oxygen passed on to the epidermis will increase. Attaches to the epidermis, pulling it in- indents overlying epidermis forms friction ridges (fingerprints)
Reticular dermis
Deep layer, made of dense irregular connective tissue. Forms cleavage lines in the skin. Not visible externally, lines are formed by alternating dense and less dense regions of fibers. This is very important for surgeons. The direction of the cleavage line determines the type of incision. Also forms flexure lines at joints to make the skin more flexible.
3 factors that determine skin color
- Melanin- reddish yellow and brownish black pigment, synthesized by tyrosinase enzyme
- Carotene- yellow orange pigment that can be used for vitamin A synthesis. Accumulates in stratum corneum and adipose tissue
- Hemoglobin- pink/red pigment found in blood cells- influences skin color in fair skinned individuals
Hair functions (2)
- Sensory structures: nerves associated with hair follicle
- Protection- scalp (from the sun), eyes (from dirt/debris), nose (hairs trap dirt and debris and prevent it from entering the lungs)
3 layers of hair
- Medulla- central core composed of large cells and air space. Absent in fine hairs of the body (vellus hairs)
- Cortex- several layers of flattened cells- less air space, cells are tightly packed together
- Cuticle- outermost layer that is most heavily keratinized, cells stacked like roof shingles. Separates individual hairs to prevent mats
3 layers of the hair follicle
- Peripheral sheath- most external layer composed of dermis. Like a follicle wall.
- Glassy membrane- “basement membrane” joining the peripheral sheath to the root sheath
- Root sheath- most internal layer derived from epidermis. Surrounds and protects the growing hair so cells can be added.
Root hair plexus
found at base of hair (hair bulb). Contains nerve endings, detects when the hair bends/moves
Dermal papilla
Provides capillaries to the hair follicle. Need to have blood supply to grow hair
Shape of hair depends on
Hair follicle: round= straight hair, oval= wavy/slightly curly, flattened= very curly
Hair matrix
Composed of rapidly dividing cells from hair bulb- new cells push old cells up and out to become the hair shaft- hair growth. Most growth is cyclical. When hair is in the dormant stage it won’t actually grow/cells won’t divide. The hair could also shed. Not all follicles are in the same stage at the same time
Telogen effluvium
Hair loss for no apparent reason- maybe poor diet or chronic stress
Alopecia universalis
Complete loss of hair on the scalp and the rest of the body. Can take shots that help to stimulate the follicles
Nail root
Underneath the skin, can’t be seen externally, covered by nail matrix- cells divide rapidly
Nail plate
Part that can be seen externally
Free edge of nail
Most terminal portion of the nail not attached to the skin
What part of the nail is responsible for nail growth?
Nail matrix responsible for nail growth- cells are very heavily keratinized, push outward during growth
Eccrine sweat glands
Especially abundant on palms, soles of feet, forehead. Sweat is mostly water and used for body temperature regulation
Apocrine sweat glands
Located in axillary and anogenital areas, function after puberty. Same components as sweat from eccrine, plus fatty substances and proteins. Function is unclear- could be pheromones as they only function after puberty
Sebaceous glands
Secretes sebum (oily substance). Sebum is largely lipid based with cell components. Release to skin is dependent on arrector pili. Empty into hair follicle, released to skin
Sebum functions (3)
- Lubricant for skin/hair
- Slows water loss from epidermal surface
- Kills bacteria
Basal cell carcinoma is a cancer of the
Stratum basale
Squamous cell carcinoma is a cancer of the
Stratum spinosum
Types of burns
- 1st degree- painful, reddened skin, inflammation. No scarring involved in healing
- 2nd degree- pain, redness, fluid filled pouches (blisters). Takes longer to heal than 1st degree burns, no scarring
- 3rd degree- full thickness burns. Treatment usually requires IV fluids, skin grafts, and heavy antibiotic use. When epidermis and dermis are burned away, so are the free nerve endings that sense pain. Most often die from dehydration (constant water loss if you have no skin in most of the body).
Functions of the skeletal system (6)
- Support- holds up the body and cradles organs
- Protection- central nervous system, some visceral organs by ribs
- Attachment point- skeletal muscle attaches to bone via tendons
- Storage- minerals and fat (yellow marrow in the bones of adults)
- Hematopoiesis- formation of blood cells in red bone marrow
- Hormone production- osteocalcin- regulates insulin release, glucose homeostasis, and energy expenditure
Cartilage is surrounded externally by
Perichondrium (tissue sheet). Contains blood vessels. Resists outward expansion of cartilage- prevents it from being too compressed
2 basic components of cartilage
- Chondrocytes
2. Extracellular matrix- has fibers, more viscous
Types of cartilage (3)
- Hyaline- articular cartilage (forming joints), costal cartilage, respiratory cartilage, nasal cartilage
- Elastic- contains more elastic fibers- external ear, epiglottis (like a trap door closing over the trachea when you swallow).
- Fibrocartilage- compressible, great tensile strength- can support a lot of weight without damage. Vertebral discs, knee, pubic symphysis
What type of cartilage is most plentiful in the adult body?
Hyaline cartilage is the most plentiful in the human body. This is found in articular cartilage (forming joints), costal cartilage, respiratory cartilage, and nasal cartilage.
What two body structures contain flexible elastic cartilage?
The epiglottis and external ear cartilages are flexible elastic cartilages
Cartilage grows by interstitial growth. What does this mean?
Interstitial growth is growth from within and is associated with a growth in length. Occurs throughout tissue- cells divide and secrete matrix in pre-existing cartilage
Appositional growth (cartilage)
Laying down new cartilage on old cartilage, associated with a growth in width. Occurs at surface- cells in perichondrium deposit new matrix on top of preexisting cartilage.
What is the functional relationship between skeletal muscles and bones?
Skeletal muscles use bones as levers to move the body
List two types of substances stored in bone and state where each is stored.
The bone matrix stores minerals (calcium and phosphate). This is what gives bone its hardness and makes it slow to degrade/break down. Bone marrow cavities store fat in adults
What are the components of the axial skeleton?
Skull, vertebral column, and rib cage
Contrast the general function of the axial skeleton to that of the appendicular skeleton.
The function of the axial skeleton is to establish the long axis of the body and to protect structures that is encloses. The function of the appendicular skeleton is to move the body to allow us to interact with the environment.
What bone class do the ribs and skull bones fall into?
The ribs and skull bones are flat bones. Long bones are most limb bones (bones that are longer than they are wide), short bones are the carpals and tarsals, irregular bones are the vertebrae and os coxa.
Diaphysis
Bone shaft. Makes up most of the length of the long bone and is the cylinder portion. Composed of compact bone “collar” with internal medullary cavity. Helps with bearing weight loads. The medullary cavity is filled with yellow marrow in adults
Epiphysis
Bone ends covered with hyaline cartilage. Irregularly shaped because these are the locations of articulation (joint formation). Composed of compact bone externally, spongy bone internally
Periosteum
Membrane that covers the bone surface, except at joints. Double layered- outermost layer is fibrous (tougher, helps protect bone, prevents periosteum from tearing when bone bends), inner layer composed of osteoprogenitor cells (these are stem cells- undifferentiated). Very well vascularized and innervated. If a bone is broken badly enough that it breaks the periosteum, the tear will contribute to the pain and bleeding experienced.
Endosteum
Covers internal bone surfaces- trabeculae in spongy bone, canals in compact bone. Also contains osteoprogenitor cells- bone growth must occur on the inside of bone to balance out the growth occurring on the outside
What would happen to a bone if you removed all of the inorganic components? Would it be able to resist compression or tension?
This would remove the mineral salts that make the bone rigid, so it would not be able to resist tension. However, its organic portion, like collagen, would still be present to help it resist tension.
Which cell has a ruffled border and acts to break down bone matrix? Which organelle would be the likely source of enzymes that can digest bone matrix?
The osteoclast, and the lysosome would contain the matrix digesting enzymes.
Organic components of bone
Cells and osteoid. Osteoid is the unmineralized matrix that forms hard bone tissue. There are multiple types of cells responsible for maintaining bone tissue. Sacrificial bonds in or between collagen molecules stretch and break easily when pressure is put on bone without damaging the bone- makes the bone more flexible
Types of bone cells (5)
- Osteoprogenitor
- Osteoblasts
- Osteocytes
- Bone lining cells
- Osteoclasts
Osteoprogenitor (osteogenic) cells
Stem cells- mitotically active cells (constantly reproducing). Can remain as osteogenic cells or differentiate to form osteoblasts
Osteoblasts
Immature bone forming cells (responsible for bone growth). Secrete unmineralized matrix (osteoid) that forms hard bone tissue. Activity of cell depends on shape (cube shaped cells secrete matrix, flattened cells are inactive). Once surrounded by matrix, osteoblasts will mature to form an osteocyte.
Osteocytes
Mature bone cell that monitors and maintains the bone matrix. Respond to mechanical stress and calcium levels. Often have several slender projections- extend through the matrix and make immediate contact with neighboring bone cells (osteoblasts/osteoclasts). This allows these cells to communicate. If the osteocyte is monitoring and decides the matrix is too thin, it will send a message to the osteoblast to stimulate it to create more matrix and vice versa.
Bone lining cells
Maintain a matrix at the bone surface. These cells have a very specific location, unlike the osteocyte.
Osteoclasts
Has a ruffled edge of the cell that contacts bone directly. Maintains, repairs, and remodels bones- breaks down old tissue- don’t want the bone to be too dense. Bone will also need to be remodeled after going through stress so it can continue to withstand stress. Important function in blood calcium homeostasis- osteoclasts will be stimulated to break down bone and get calcium
Inorganic components of bone
Mineral salts- mostly calcium phosphate packed around collagen fibers. This is what gives bone its hardness and makes it slow to degrade/break down. This is why the bones are the last to break down after death.
Bones don’t begin with bone tissue. What do they begin with?
Bones begin as fibrous membranes or hyaline cartilage. Hyaline cartilage is used as a “blueprint” to form ossified bone in bones below the skull. In the skull and clavicles, bone formation begins from a fibrous membrane
When describing endochondral ossification, some say “bone chases cartilage”. What does that mean?
The cartilage model grows, then breaks down and is replaced by bone.
Where is the primary ossification center located in a long bone? Where are the secondary ossification centers located?
The primary ossification center in a long bone is located in the center of the shaft (diaphysis). The secondary ossification centers are in the epiphyses (bone ends). Secondary ossification begins in adolescence- steps are similar to primary ossification, but the spongy bone is retained in bone ends. No medullary cavity is formed.
As a long bone grows in length, what is happening in the hypertrophic zone of the epiphyseal plate?
The chondrocytes are enlarging and their lacunae are breaking down and leaving holes in the cartilage matrix.
Intramembranous ossification steps (4)
- Mesenchymal cells differentiate into osteoblasts- form a primary ossification center (clump of osteoblasts)
- Matrix is secreted by the osteoblasts, then calcified
- Formation of periosteum and immature spongy bone
- Compact bone replaces some spongy bone, red marrow develops
Bone growth zones (4)
Bone growth is accomplished by interstitial growth, occurs at the epiphyseal plate.
- Proliferation
- Hypertrophic
- Calcification
- Ossification
Endochondral ossification steps (5)
- Formation of a bone collar (week 9 in embryonic development)
- Cavity formation in diaphysis center
- Formation of spongy bone (month 3)
- Formation of medullary (marrow) cavity, elongation of diaphysis
- Secondary ossification begins in epiphyses (childhood to adolescence)
Which stimulus is more important in maintaining homeostatic blood calcium levels- PTH or mechanical forces?
Parathyroid hormone maintains blood calcium levels
How do bone growth and remodeling differ?
Bone growth increases bone mass, like during childhood or when a lot of stress is placed on the bone. Bone remodeling follows bone growth to maintain the proper proportions of the bone considering the stresses placed on it.
Despite daily exercise, the bones of astronauts in the International Space Station get thinner and weaker during their time in space. Why does this occur?
The bones get thinner and weaker because they are deprived of the normal loading forces placed on the bones by gravity. Exercise can help to some extent but is not a substitute for gravity.
What are 3 measures that may help to maintain healthy bone density?
Sufficient vitamin D, calcium, and weight bearing exercise
What name is given to “adult rickets”?
Osteomalacia. Osteomalacia only occurs in adults- calcium salts are not deposited to the tissue, so the bone bends really easily and pushes on the nerves, causing pain. This can be reversed with normal calcium intake.
Rickets
Rickets only occurs in children but tends to be more severe as children are still growing. Can result in permanent bone deformities and cause skull deformities (dents), misshapen pelvis due to weight of the body and visceral organs, rib cage can be deformed (problematic, it’s very important for breathing). Caused by insufficient calcium in diet, low vitamin D. Mineral salts are deposited in bone in much lesser amounts- bone is weak/soft
Osteon
Structural unit of compact bone. A single osteon is composed of several layers (lamella) packed closely together- the walls of one lamella with be in contact with the other in a concentric manner. Fibers always run in opposite direction to adjacent lamella. Function- helps the bone to withstand pressure and stress. Allows the bone to bend/twist without breaking.
Canals
Run through the center of each osteon (haversion canal). Central (haversion) canal contains nerves and blood vessels (artery and vein). Perforating canals connect nerve/blood supply of marrow cavity to central canal. Allows the marrow cavity to be supplied with blood and nervous fibers.
Interstitial lamellae
Incomplete lamellae found in between complete osteons. Fill gaps between osteons- osteons are circular and there are no corners, so there will be spaces in between- you don’t want air pockets in bone
Circumferential lamellae
Found just deep to periosteum, complete layer. Extend completely around the circumference of diaphysis (outermost lamellae of compact bone). Resists twisting of long bone, bundle the osteons together
Growth hormone
Controls (increases) activity at the epiphyseal plate- cartilage cells divide faster or divide more, increasing bone length. Hypersecretion results in gigantism, hyposecretion results in dwarfism.
What 3 factors control bone deposition and resorption?
- Parathyroid hormone (PTH) released in response to decreasing Ca+ blood levels
- Calcitonin decreases blood calcium levels
- Mechanical stress- bones are strongest where they are subject to high pressure (Wolff’s Law), or where they are most likely to break
How are joint mobility and stability related?
The more stable a joint is, the less mobile it is
Functional categories of joints (3)
- Synarthroses- not movable
- Amphiarthroses- slightly movable
- Diarthroses- freely movable
Structural categories (3)
- Fibrous- joints composed of collagen fibers of connective tissue
- Cartilaginous- bones joined by cartilage
- Synovial- contain a synovial cavity
Types of fibrous joints (3)
- Gomphoses- joins teeth to the bony alveolar sockets
- Syndesmoses- bones are connected to each other only by ligaments
- Sutures- found only between bones of the skull
Types of cartilaginous joints (2)
- Symphyses- fibrocartilage joins bone- pubic symphysis
2. Synchondroses- bones united with a plate of hyaline cartilage- costal cartilage
Evan is 25 years old. Would you expect to find synchondroses at the ends of his femur?
No. By age 25, his epiphyseal plates have fused and become syntoses.
Nick bent over to pick up a dime. What movement was occurring at his hip joint, at his knees, and between his index finger and thumb?
Nick’s hip joint was flexed, his knees were extended, and his thumb was in opposition to his index finger
Structures associated with synovial joints (6)
- Articular cartilage- hyaline cartilage covering bone ends
- Joint cavity- extremely small space between articulating bones
- Articular capsule- two layered capsule that encloses the joint cavity- forms the walls of the joint cavity.
- Synovial fluid- stored in articular cartilages when the joint isn’t active
- Reinforcing ligaments- bandlike ligaments that join articulating bones.
- Innervation (sensory nerve fibers) and rich vascularization
Bursae
Flattened sacs that contain a small amount of synovial fluid. Found where ligaments, muscles, skin, tendons, and/or bone would rub together. Function- reduce friction between adjacent structures
Tendon sheath
Elongated bursa that wraps completely around a tendon subjected to frequent friction. Found in “crowded” tendon areas (example- tendons in the wrist and ankle). Functions- prevents excessive friction for a particular tendon
Factors that influence joint stability (3)
- Articular surfaces- the better 2 bones fit together, the more stable the joint in general
- Ligaments- generally, the more ligaments that surround the joint, the stronger the joint (unless ligaments are the only supportive structure
- Muscle tone- if the muscles are always slightly contracted, they pull slightly on tendons. This braces the joint
Temporomandibular joint
Modified hinge joint. Articular disc divides the synovial cavity into superior and inferior portions. Superior- allows lateral excursion. Sits closer to the mandibular fossa. This is why you can move your jaw left and right. Inferior- allows elevation/depression. This is why you can move your jaw up and down. Both of these movements occur during chewing.
Glenohumeral joint
Ball and socket joint. Features:
- Reinforcing ligaments are very thin and loose. Coracohumeral ligament and glenohumeral ligaments (3)- wrap around joint to provide stability
- Rotator cuff- muscles and tendons encircle the joint- easily torn by excessive movements, like circumduction
- Glenoid labrum- rim of fibrocartilage around glenoid fossa- provides some stability
Elbow joint
Stability is provided by close fit of the trochlea (on humerus) and trochlear notch (on ulna). This is again based on how the articular surfaces fit together. Articular capsule is thin, loose- allows flexion/extension movement. Ulnar collateral ligament (medial) and radial collateral ligament (lateral) prevent side to side movement
Coxal joint
Ball and socket joint. Reinforced by a deep socket and strong ligaments. Acetabulum of os coxa has acetabular labrum to further deepen the socket. Ligamentum teres- ligament of the head of the femur. This is not found in the glenohumeral joint. Serves as a joint stabilizer and provides blood and nerve supply to the head of the femur
Knee joint
Single joint cavity shared by 3 separate joints- femoropatellar and 2 tibiofemoral joints. Anterior surface of the knee has no it is capsule, is enclosed with ligaments. Important structures are the menisci and ligaments.
Menisci
Forms ridges laterally and medially. Help with absorbing shock.
Only attached to the tibia along the outer margins of the bone, the rest is unattached. Therefore, it can tear or rip away easily. This is a very common sports injury, especially with sudden or lateral movements. Usually needs surgery to fix it
Intracapsular ligaments (cruciate ligaments) of the knee
Secure articulating bones, prevent displacement. Anterior cruciate ligament (ACL) prevents forward sliding of tibia, prevents hyperextension. This is also a very common sports injury caused by sudden changes in direction. The ACL is smaller and thinner and therefore tears more easily, so it’s more of a problem than the PCL. Posterior cruciate ligament (PCL) prevents backward sliding of tibia and forward sliding of femur.
Cartilage tears
Joint cartilage (usually menisci) is overstretched, can snap and break. Compression (pushing together) and shear stress (rubbing against each other) occur simultaneously. This will rip cartilage if it occurs at the same time. Healing (if any) takes time. Thick cartilage will probably have too much damage and not be able to heal through diffusion (cartilage is avascular). Joint is less stable after injury.
Sprains
Ligaments reinforcing joint are damaged. Completely torn ligament- more difficult to repair. Treatments: time/immobilization, sew ends of the ligament together (basically like trying to sew spaghetti together- very difficult), or grafting- taking a piece of tendon and using it to replace the torn ligament.
Why are dislocated joints more likely to dislocate in the future?
This is because the ligaments have been overstretched and will remain overstretched when the joint is put back in place.
Osteoarthritis
Most common form of chronic arthritis- progresses slowly and is irreversible. Poorly aligned and/or overused joints are most likely to exhibit OA- more articular cartilage is destroyed than can be replaced by the body. Exposed bone tissue rubs together, and can form bone spurs- deforms bone ends (excessive growth of bone in strange places), restricts movement at joint because it gets in the way.
Rheumatoid arthritis
Autoimmune chronic inflammatory disorder (immune system is attacking your joints). More women affected than men, typically diagnosed between ages 30-50. Bilateral degenerative condition (occurs in the same joints on both sides)- joints of fingers, wrist, ankles, feet most likely to be affected. Individuals affected have flare ups followed by periods of remission (mostly symptom free). It never goes into a permanent period of remission, however, and flare ups will usually get worse over time.
What can rheumatoid arthritis result in over time?
Accumulation of synovial fluid and formation of a pannus- a pannus is a thickened portion of the synovial membrane- breaks down cartilage tissue over time. Ankylosis can occur- scar tissue forms where the hyaline cartilage tissue once was, fusing bones together
