INTEGUMENT AND BONE TISSUE Flashcards
Epidermis
-made up of epithelial tissue
-constantly shedding and regenerating
-composed of keratinized stratified squamous epithelium
Keratinized stratified squamous epithelium
4 main cell types:
-Keratinocytes
-Melanocyte
-Merkel cells (tactile cells)
Keratinocytes
-producing keratin
-tough fibrous protein
-provides protection
Melanocytes
-produce melanin
-important for protection from UV
-melanin is a pigment that protects against damage from UV radiation
Merkel cells (tactile cells)
-touch receptor cells
-in stratum basale
-when compressed, send signals to nerves
Stratum basale
-deepest, single layer of cuboidal to low columnar keratinocytes in contact with basement membrane
-cell division occurs here
-also contains melanocytes and tactile cells
-continuous cell division
-produces all other layers
-as cell divides, new cell is pushed toward external surface
Stratum spinosum
-layer of 8-10 keratinocytes and some dendritic cells
-several layers of keratinocytes attached to neighbours by desmosomes
-epidermal dendritic cells present
Stratum granulosum
-3-5 layers of keratinocytes with distinct granules in cytoplasm
-keratinization begins in this layer
-non dividing cells
-filled with granules of keratin
-as keratin is produced causes nucleus and organelles to disintegrate
Stratum lucidum
-only present in thick skin
-fingers tips, palms, soles
-2-3 layers of anucleate, dead keratinocytes
-seen only in thick skin (i.e., palms of hands, soles of feet)
Stratum corneum
-most superficial layer of epidermis
-20-30 layers of dead, flattened, anucleate, keratin-filled keratinocytes
-~20 layers of flat cell remnants
-continuously shed and replaced
Dermis
-dermis has extensive nerve fibers
-sensory nerve fibers
-tactile corpuscles
-detect pressure, vibration and cold
-motor nerve fibers
-control blood flow and gland secretion
-dermal blood flow
-supply nutrients to epidermis and dermis
-important role in body temperature and blood pressure regulation
Papillary region (dermis)
-consists of areolar connective tissue with capillaries, tactile receptors and free nerve endings
-superficial layer of dermis
-composed of areolar connective tissue
-forms dermal papillae
-houses capillaries and tactile receptors
Reticular region (dermis)
-deeper layer of dermis
-composed of dense irregular connective tissue
-surrounds and supports hair follicles
-sebaceous glands and sweat glands, nerves and blood cells
-consists of dense irregular connective tissue with adipose cells, hair follicles, nerves and glands
Subcutaneous
-attaches the skin to underlying tissues and organs
-acts as an energy reserve
-provides thermal insulation
-drugs often injected here
-not considered part of the integument
-deep to dermis
-composed of areolar and adipose connective tissue
Hair
-pilus ( single hair )
-composed of dead, keratinized epidermis cells
-functions:
-protection
-heat retention
-sensory reception
-main components:
-shaft: above the surface of the skin
-root: deep to the skin surface
-bulb: made of epithelial cells, where the hair originates
Nails
-composed of keratinized epidermal cells
-found on the dorsal surfaces of the ends of the fingers and toes
-functions:
-protection
-assist in grasping objects
Sebaceous glands
-connected to hair follicles
-secretes oily substance into hair follicle
Sebum:
-prevents dehydration of hair and skin
-inhibits growth of certain bacteria
-oil glands are stimulated by androgens
Eccrine sweat glands
-occur over most of the body and open directly into the skins surface
-cools the body as sweat evaporates from the skin
-secretes a watery substance
-sweat while exercising ( no order )
-secretes a watery substance that helps to cool the body and eliminates small amounts of waste
Apocrine sweat glands
-located in the skin of the axilla, groin, areolar, and bearded facial regions of adult males
-released during sexual activity
-produce waxy substance
-found in ear canal
-secrete a water substance with proteins and lipids
-susceptible for bacteria growth leading to odor
-emotional or stressful sweating
Know the 4 steps involved in wound healing
- cut blood vessels bleed into the wound
- blood clot (scab) forms
- blood vessels regeneration
- epithelial regeneration
- cut blood vessels bleed into the wound
-brings clotting proteins leukocytes and antibodies
-inflammation
- blood clot (scab) forms
-temporary barrier
-prevents the entry of pathogens
-macrophages and neutrophils clean the wound of cellular debris
-proliferation
- blood vessels regeneration
-also creates granulation tissue
-vascular connective tissue
-macrophages begin to remove clotted blood
-fibroblasts produce new collagen fibres
-remodelling
- epithelial regeneration
-due to cell division at the edge of the wound
-scar tissue
-more thick and tough
-fibrosis
Regeneration
-replacement of damaged cells with cells of the same type
Fibrosis
-replacement of damaged cells with different cells
-produces scar tissue
-composed primarily of collagen fibres produces by fibroblasts
First degree burn
-only involves the epidermis
-mild pain and redness
-no blistering or loss of function
-ex. mild sunburn
Second degree burn
-involves the epidermis and dermis
-redness, blister formation, edema and pain
-some skin functions are lost
-ex. severe sunburn or scalding from hot liquid
Third degree burn
-involves epidermis, dermis and subcutaneous layers
-most functions are lost, and region is numb
Periosteum
-tough sheath of dense, irregular connective tissue on the outside of the bone
Medullary cavity
-space within the diaphysis
-contains fatty yellow bone marrow in adults
Endosteum
-membrane that lines the medullar cavity
Diaphysis
-shaft of the long bone
Epiphysis
-form the distal and proximal ends of a long bone
Metaphysis
-area where the epiphysis and diaphysis join
-width of the bone is changing
Articular cartilage
-thin layer of hyaline cartilage
-covers the epiphysis of long bones
-found where the bone forms an articular (joint) surface
Osteoprogenitor cells
-unspecialized bone stem cells
Osteoblasts
-formed from osteoprogenitor cells
-cuboidal shape
-bone building cells
Osteocytes
-mature bone cells derived from osteoblasts
-lost bone forming ability
-maintain bone matrix
Osteoclasts
-bone breakdown cells
-large, multinuclear
Red bone marrow
-hemopoietic
-blood cell forming
-contains reticular connective tissue, immature blood cells and fat
-in children:
-located in spongey bone of most bones and medullary cavity of long bones
-in adults:
-located in portions of the axial skeleton and proximal epiphyses of humerus and femur
Yellow bone marrow
-product of red bone marrow degeneration in adults
-fatty substance
-may convert back to red bone marrow
-during severe anemia (low erythrocytes)
-facilitates production of additional erythrocytes
Spongy bone
-located within compact bone
-lighter and appears porous
-support and protect red bone marrow
-spongey bone lacks osteons
Trabeculae
-lamellae are arranged in a lattice of thin columns
Compact
-strongest form of bone tissue
-resists stresses by weight and movement
-appears white, smooth and solid
Osteons
-unites of compact bone
-formed from concentric lamellae
Concentric lamellae
-cylindrical rings of lamellae which are rich in collagen
-surround the nutrient canals of osteons
Interstitial lamellae
-found between osteons
-leftover fragments of older osteons
Lacunae
-small spaces between lamellae
-house osteocytes
Canaliculi
-small channels filled with extracellular fluid connecting the lacunae
-allows for contact and communication
Central canal
-location of blood and lymphatic vessels
-within osteons
Perforating canals
-a channel within bone tissue that allows blood vessels and nerves to connect the outer part of the bone with its interior
-run perpendicular to the long axis of the bone and intersect with the central canals of osteons
Ossification
-the process of forming new bone
-steps:
1. initial formation
-ossification
-replace connective tissue with bone
2. growth
3. remodeling
4. repair of fractures
Epiphyseal growth plate
-found in adolescents
-layer of chondrocytes that are proliferating
-adds length and secreting extracellular matrix
-Ca salts
Epiphyseal line
-in adults, the epiphyseal cartilage is no longer present
-elongation of bones has stopped
-epiphyseal line
-replaces the epiphyseal plate
-growing cartilage is replaced by calcified bone
Explain bone matrix formation and resorption
Know bone’s role in Ca2+ homeostasis
Comminuted fracture
bone is splintered into several small pieces between the main points
Complete fracture
bone is broken into two or more pieces
Compound (open)
broken ends of the bone protrude though the skin
Greenstick
partial fracture; one side of bone breaks-the other side is bent
Hairline
fine crack in which sections of bone remain aligned (common in skull)
Impacted
one fragments of bone is firmly driven into the other
Stress
thing fracture due to repeated, stressful impact such as running (these fracture often are difficult to see on x-rays, and a bone scan may be necessary to accurately identify their presence)
Bone repair
1.formations of a fracture hematoma
2.fibrocartilaginous callus forms
3.bony callus forms
4.remodelling occurs
Describe the general functions of bone
Functions:
1.Provides
-structural framework
-point of attachment for tendons and ligaments
-protects internal organs
2.Assist in body movements
-levers for movement
3.Participate in blood cell production
-hemopoiesis
4.Storage of mineral and energy reserves
-triglycerides in adipose cells of yellow bone marrow
-calcium and phosphorous
Explain the structural components of a long bone
-long bones contain yellow and red bone marrow
-produce blood cells
-bone that has a shaft and two ends and is longer than it is wide
-have a thick outside layer of compact bone and an inner medullary cavity containing bone marrow
-Diaphysis:
-shaft of the long bone
-Epiphysis:
-form the distal and proximal ends of the long bone
-Metaphysis:
-area where the epiphysis and diaphysis join
-Periosteum:
-tough sheath of dense, irregular connective tissue on the outside of the bone
-Medullary Cavity:
-space within the diaphysis
-contains fatty yellow bone marrow in adults
-Endosteum:
-membrane that lines the medullar cavity
Compare and contrast the structure and location of the two types of bone
marrow
-Red Bone Marrow:
-contains blood stem cells that can become red blood cells, white blood cells, or platelets
-location in children:
-located in spongey bone of most bones and medullary cavity of long bones
-location in adults:
-located in portions of the axial skeleton and proximal epiphyses of humerus and femur
-Yellow Bone Marrow:
-made mostly of fat and contains stem cells that can become cartilage, fat or bone cells
-location in adults:
-found especially in the medullary cavity of long bones
-located in children:
-located in the hollow cavity of long bones
-typically found at the center surrounded by red bone marrow
Name the four types of bone cells and their functions
-Osteocytes:
-mature bone cells derived from osteoblasts
-lost bone forming ability
-maintain bone function
-Osteoclasts:
-bone breakdown cells
-large, multicellular
-Osteoprogenitor Cells:
-unspecialized bone stem cells
-precursors to the more specialized bone cells
-play a prodigal role in bone repair
-Osteoblasts:
-formed form osteoprogenitor cells
-cuboidal in shape
-bone building cells
