Exam 2: Rest of integumentary system, skeletal system, joints Flashcards
What is the primary function of keratin and keratohyalin (protein)
provides strength to hair, skin, nails
what are the 2 types of keratin and where are they found
- soft: found in skin (as cornified cells), they desquamate (fall off)
- hard: found in fingernails & hair, do not desquamate
How is skin classified
Based on the structure of the epidermis
What are the 2 kinds of skin
thick skin:
contains all 5 of epidermal strata & stratum corneum has many layers; found in areas of pressure & friction (palms of hands, soles of feet)
thin skin:
has all 5 strata but there are fewer layers of cells in strata; more flexible, hairs only found in thin skin
What is meant by “total skin thickness”
the epidermis and dermis combined (dermis accounts mostly for skin thickness)
What determines skin color
mostly via pigments (like melanin)
What is melanin/how does it determine skin color
melanocytes get phagocytized (engulfed) by keratinocytes - acquisition of melanosomes (vesicles with melanin)
what causes variation in skin color
variation in melanocortin 1 receptors - more melanin=darker skin, less melanin=lighter skin
UV exposure also darkens melanin already present
Temporary changes in skin coloration include
erythema
cyanosis
pale skin
other pigments
define erythema
reddish hue of skin due to increased blood flow; generally happens on face when hot or blushing
define cyanosis
bluish skin due to decreased blood flow (oxygen); occurs when someone is choking
define pale skin
reduced blood flow resulting in pale skin color; occurs when someone is startled or about to faint
What is another pigment that can temporarily change skin coloration
carotene (from carrots) - can turn skin orange if large amount of carrots are consumed in a short amount of time
What is the dermis comprised of
comprised of connective tissue (it is a CT as whole)
made of protein fibers (mostly collagen, but has some reticular & elastic)
fibroblasts and adipocytes
nerve endings and hair follicles
What are the 2 layers of tissue in the dermis
- papillary:
contains dermal papillae (projections that make up fingerprints) and circulation structures (this is why it bleeds if you get a deep enough cut) - Reticular:
made of irregular connective tissue, joins skin with subcutaneous tissue (hypodermis)
What is the hypodermis
also known as the subcutaneous tissue, attaches skin to underlying tissue (like muscle tissue), subcutaneous fat storage (1/2 of body’s fat stored here - this is needed for insulation, padding, energy source)
Where is the sensory system located
dermis
what is the sensory system
nerve endings
what kinds of nerve endings exist in the sensory system and what are their functions
free nerve endings (pain, itch, tickle, temperature)
Merkel discs (light touch)
hair follicle receptors (light touch)
Pacinian corpuscle (deep pressure)
Meissner corpuscle (2 point stimulation
Ruffini end organ (continuous touch/pressure)
What are the types of hair
Lanugo
Terminal hair
Vellus hair
what is lanugo
delicate, soft, non-pigmented hair present on fetuses and newborns
what is terminal hair
coarse, pigmented hair found on scalp, eyelids, and eyebrows
what is vellus hair
fine, non-pigmented body hair found throughout the rest of the body
Structures of hair (draw diagram)
cross-section of hair (draw diagram)
hair shaft, hair follicle, root of hair
Concentric layers of hair:
Cuticle (outer) - has 1 cell layer of hard keratin
cortex - has 1 cell layer of hard keratin
medulla (center) - has 2-3 layers of soft keratin
stages of hair growth
Growth stage:
-period of time where hair actively grows, hair formation by matrix cells within the follicle
-differentiation &keratinization
-addition of cells at the base of the root = growth
-can last several weeks to couple of months
Resting stage:
-no hair growth
-old hair eventually replaced by the new one
*hair does not grow continuously, growth depends on the person and individual hair strand
How does hair color occur
varying concentrations of melanin
Types of melanin:
-eumelanin: brown or black (brunette family of color)
-phaeomelanin: Red (high concentrations) or blonde (less concentration)
how does hair get its texture
based on shape of hair follicle
oval=curly
more round=straight or wavy
what are the nails composed of
stratum corneum (hard keratin)
these cells do not slough off like cornified cells in the epidermis, they grow continuously
glands in skin
Sebaceous glands (exocrine):
-produce sebum (oil) which prevents water loss and bacterial infection, most associated with hair
Sweat glands:
-merocrine sweat glands are responsible for temperature regulation via sweating (evaporative cooling)
-apocrine sweat glands are associated with hair and are active for first time during puberty (pheromone release in evolutionary times), located under armpits
(Others):
Ceruminous glands:
-produce ear wax
Mammary glands:
-milk production
Additional Integument functions
temp regulation:
-sweat production - evaporative cooling
changes in blood flow in response to changes in environment:
-vasodilation; more warm blood flows to skin, results in heat loss (cool off)
-vasoconstriction; less warm blood flows to skin, results in heat retention (get warm)
Vitamin D production process
Vitamin D is hormone, not true vitamin
Production:
-Occurs mostly in stratum Basale (deepest layer of epidermis)
-Skin UV exposure triggers VitD3 production
-D3 released into blood, converted to active form - (stimulates Ca++ & phosphate uptake at intestines and kidneys)
What is common pathology in integumentary system
burns
Degree refers to what of a burn
depth
what combines %BSA & depth of burns
burn severity
Define first-degree burn
only epidermis is affected
some pain, redness, swelling
fairly common
Define second-degree burn
damage to epidermis & dermis
these vary b/c dermis is thick
can be red, tan, or white (if deep)
can scar if deep enough
Define third-degree burn
epidermis and dermis completely destroyed
deeper tissues may be involved (like hypodermis)
sensory structures destroyed (affects ability to feel)
tan or brown color, leathery look
skin grafts often necessary
Define major burn
3rd degree burn covers over 10% BSA OR
2nd degree burn covers over 25% BSA OR
Burns to hands, face, genitals, or anal region
Define moderate burn
3rd degree burn covers 2-10% BSA OR
2nd degree burn covers 15-25% BSA
Define minor burn
3rd degree burn covers less than 2% BSA OR
2nd degree burn covers less than 15% BSA
what are the components of the skeletal system
bones
cartilages: hyaline cartilage, fibrocartilage, elastic cartilage
tendons: connects muscles to bones
ligaments: connects bones to bones
Bone matrix composition
organic portion: collagen fibers (provides flexible strength)
Inorganic portion: hydroxyapatite - CaPO4 crystals (provides weight bearing strength
What are the different bone cells
Osteoblasts - production of matrix
Osteocytes - maintenance of matrix
Osteoclasts - breakdown of matrix
Osteochondral progenitor cells (stem cells)
Define function of osteoblasts
secrete collagen , proteoglycans, hydroxyapatite precursor
cells surround themselves by matrix
mature into osteocytes (trapped in lacunae)
Ossification occurs - formation of bone by osteoblasts
Define function of Osteocytes
maintenance of bone
surrounded by matrix (in lacunae)
projections extend into canaliculi to communicate with other osteocytes
transport of nutrients to each other through
-diffusion via liquid surrounding cell and filling lacunae and canaliculi
-gap junctions between cells
Define function of Osteoclasts
Derived from monocytes (White blood cells)
-multinucleated, arise from fusion of several cells
cause bone breakdown
Define bone breakdown process (draw osteoclast diagram)
-Podosomes form sealed compartment
-osteoclast secretes
H+ (hydrogen ions) - degrades bone matrix (hydroxyapatite) &
enzymes - degrades organic proteins (collagen)
-degraded products reabsorbed at ruffled border (moved through osteoclast, then secreted to enter blood)
Define function of bone stem cells
mesenchymal stem cells: make osteochondral progenitor cells (can differentiate into osteoblasts or chondroblasts - osteoblasts mature to osteocytes)
Hematopoietic stem cells:
produce monocytes (fuse to form osteoclasts)
What is bone remodeling
Removal of old bone material by osteoclasts, formation of new bone matrix by osteoblasts
Constant process
Basic Multicellular Unit (BMU)
-temporary assembly of osteoclasts & osteoblasts
-travel along bone, remove old matrix & replacing with new
*This BMU activity renews entire skeleton every ~10 years
(turns woven (developing) bone to lamellar/lamellae (mature) bone)
Types of bone
Cancellous (spongy) Bone
Compact Bone
Describe cancellous (spongy) bone
lots of open spaces
composed of trabeculae:
-interconnecting rods or plates of bone that create spaces
-spaces filled with marrow (primarily red)
-covered with endosteum (tissue lining inner spaces of bone)
-oriented along stress lines
Describe Compact Bone
(Draw diagram of osteon)
Very dense
Contains osteons:
-central canal (Haversian canal)
*blood vessels
-Concentric Lamellae
*Bone matrix around central canal
-Lacunae & canaliculi
*Osteocytes & fluid
-Blood vessels
*Central Canal - run length wise
*Perforating (Volkmann’s) Canal - run width wise
what are the different bone shapes
long: longer than it is wide
short: Cube-shaped
flat: Plate like
irregular: do not fall into other categories
Long bone structures
Diaphysis:
-shaft of long bone
-mostly compact bone
Epiphyses:
-ends of long bone
-mostly cancellous bone
Epiphyseal plates:
-near epiphyses
-site of bone growth
-becomes epiphyseal line when bone growth stops
Medullary Cavity:
-hollow center in shaft
-contains marrows (red marrow during childhood, converts to yellow as we age)
Periosteum:
-Tissue membrane on outer surface of bone
-Outer layer - Dense irregular CT, continues with tendon
-Inner Layer - Bone Cells
Endosteum:
-lines all internal spaces including spaces in cancellous bone
Flat bone structure
-no diaphyses, epiphyses
-sandwich of cancellous between compact bone
Short & irregular bone structure
compact bone that surrounds cancellous bone center
Describe growth in bone length
Occurs at epiphyseal plates
Formation of new cartilage:
-interstitial growth = growth in length of bone
-appositional growth = growth in diameter of bone
Describe growth in bone length
Occurs at epiphyseal plates
Formation of new cartilage:
-interstitial growth = growth in length of bone
-appositional growth = growth in diameter of bone
Closure of epiphyseal plate (around adult stature):
-ossification at epiphyseal line
*occurs between 12 and 25 years of age
Zones of the epiphyseal plate (Draw long bone and label)
Near Epiphysis:
-Zone of resting cartilage
*very slowly dividing chondrocytes
-Zone of proliferation
*Chondrocytes divide more rapidly - produce columns
-Zone of hypertrophy
*chondrocytes mature and enlarge
-Zone of calcification
*Chondrocytes take on calcium, and are replaced by bone
:Near Diaphysis
Describe ossification centers
Primary ossification center:
-first area of bone to ossify
-usually during fetal development in central portion of bone
Secondary ossification center:
-areas of ossification that appear after primary ossification center
-mostly after birth & adolescence
Describe growth at articular cartilage
slow chondrocyte division, similar to in zone of resting cartilage
No ossification
how does nutrition affect bone growth
Nutrition:
-calcium & protein during development
-Vitamin D - necessary for absorption of calcium from intestines
*Lack/deficiency of VitD reduces hydroxyapatite, which reduces bone strength causing them to be soft = rickets in children, Osteomalacia in adults
-Vitamin C - necessary for collagen synthesis by osteoblasts
*Lack/deficiency of VitC reduces collagen, which reduces flexible strength of bone, causing them to be brittle = scurvy
how do hormones affect bone growth
Growth hormone: pituitary gland
- stimulates interstitial cartilage growth & appositional bone growth
Thyroid hormones: thyroid gland
-allows Growth hormone (GH) & other hormones to have full effect
Sex Steroids: gonads
-testosterone - growth @ puberty
-estradiol - causes closure of epiphyseal plates & cessation of growth
Describe the bone repair process
- Hematoma formation
-localized mass of blood within a confined space
-usually clot forms
-swelling & inflammation - Callus Formation
-connection of broken bones
*internal callus - between broken ends and medullary cavity
*External callus - around ends of fracture
-stabilization of bones via cartilage collar
-applying a cast helps to stabilize - Callus ossification
-replacement of cartilage in external callus by woven, cancellous bone
-ossification of internal callus
-additional bone stabilization - Bone remodeling
-replacement of callus by mineralized bone
-restoration of medullary cavity
Describe calcium homeostasis
-bones = storage site for Ca++
-shift out of homeostasis: too much or too little Ca++ in the blood
-signals whether to release or absorb Ca++ from or into bones
*Activity of osteoblasts & osteoclasts
-Hormonally mediated
*parathyroid hormone (PTH)
*Vitamin D
*Calcitonin
How are joints classified
classes of joints are based on structure
what are the joint classifications
Fibrous
Cartilaginous
Synovial
Describe fibrous joints
-2 bones united by fibrous connective tissue
-very little movement
Examples:
*sutures - seams between bones of skull
*Fontanels - flexible joints of infant skull
*syndesmoses - slightly moveable joint made of ligaments between farther apart bones
*Gomphoses - pegs in sockets (teeth in mandible & maxillae)
Describe Cartilaginous joints
-2 bones united by cartilage
Examples:
*Synchondrosis - bones joined by hyaline cartilage, little or no movement
(between 1st rib & sternum)
*Symphysis - bones joined by fibrocartilage, slightly flexible, some shock absorption
(pubic symphysis, intervertebral discs)
Describe Synovial joints
-2 bones united by fluid-filled capsule
-considerable movement between articulating bones
-hyaline cartilage at articular surfaces of bones
-some synovial joints have meniscus
Describe meniscus
-pad of fibrocartilage
-helps with (synovial) joint stability
(found in knee and wrist)
Describe synovial joint capsule
-holds bones together
*fibrous capsule - outer layer of synovial joint capsule, made of dense regular CT
*Synovial membrane - inner layer of synovial joint capsule, modified CT cells
*Joint cavity in capsule - contains synovial fluid
*Bursa - extension of joint cavity (in some joints), extra cushion
What injury could occur to meniscus
meniscus tears are a common sports injury
Treatment: rest, sometimes surgery if severe
Locations: Knee, wrist
What injury could occur to bursa in synovial joint capsule
Bursitis: inflammation of bursa
-caused by overuse, injury, sometimes infection
Treatment: rest, anti-inflammatory medicines
Common locations: shoulder, elbow, hip
